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Acute reversible lens opacity: Caused by drugs, cold, anoxia, asphyxia, stress, death and dehydration
Exptl Eye Res. (1970) 1 0 , 1 9 - 3 0
Acute Reversible Lens Opacity: Caused by Drugs, Cold, Anoxia, Asphyxia, Stress, Death and Dehydration F . T. F R A U N F E L D E I ~ ~ N D 1=[. IL BUI~NS
Depa~,tme,nt of Oplsthaln~ology, University[ of Oregon Med iex~l School,. Port,land, Ore. 9720~, ',U.S.A, and,
D iv'i.~ion of Ophthnlmology, U~,ive,rsi~,y of Arkansas Aledical School, Little Rock, A r k . 72201, U.S.A. (Received 26 Noven~ber 19~9, Boston) Acq~te experimental lens opacities reported to be caused by narcotics, phenoghi~zines, ¢::pi:~ephrine, anoxia, and certain types of lens opacities induced by death, asphyxia, cold or s t r c ~ are prevented by closure of the animal's eyelids. An unawareness of the imporLance of eyelid position has ted to confimion cJoncerning the pathogenesis of m a n y of these lens changes, l~ost o£ these experimental c~taract~ e~n be classified into a si:aglo gro~p ~vith commo~x chaxaot6ris$ics, for which we propose the term "~eut~ reversible lens opacity". The opacity is a reversible loss of tr~rmpare~ey of $he superficial anterior leas cortex which is prevented by closure of the eyelids. This type of ¢attrract m a y be produced by mechanical methods or agents which interfere w i t h lid closure or depress the blir~k reflex. The lens op~cit,y m a y regress eve:~ tho~gh the initiating stimulus is maintained. Although dehydration of the aqueous h u m o r and lens is the most i m p o r t a n t factor in development of the lens tra~mp~rency change, there ave other factors which also play ~ role. l. Introduction
I n 192S a c u t e r e v e r , s i b l e loss o f l e n s t r a n s p a r e n c y in l i v e or d e a d r a t s w a s r e p o r t e d b y hold;.ng o p e n t h e e y e l i d s m a n u a l l y . N o c a t a r a c t s d e v e l o p e d if t h e a n_imaFs e y e l i d s w e r e cto..qed ( G o l d n s ~ m n ,~nd :R.~tbinowi~z, 1928). W e f o u n d t l m ~ r n a u y p r e v i o u s l y r e p o r t e d acute, e x p e r i m e n t a l c a t a r a c t s p r o d u c e d b y v a . r i o u s d r u g s could[ b e p r e v e n t e d by simply closing the animal's eyelids, and the concept of "a.c~te reversible lens o p a c i t y " w a s i r t t r o d u c e d %0 d e s c r i b e t h i s p h e n o m e n o n ( F r a u n f e l d e r an(] :Burns, 1966). Tim p~Lrpose o f thSs p a p e r is to d e f i n e a n d r e c l a s s i f y m a n y p r e v i o u s l y d e s c r i b e d e x p e r h u e n t a l l e n s c,A a n g e s i n t o o n e g r o u p , t o d e s c r i b e t h e e f f e c t of e n v i r o n m e l l t , al c h a n g e s on t M s t y p e l e n s c h a n g e , a n d t o d e f i n e m o r e d e ~ r l y t h e i n v i c e c o l d c a t a r a c t , 2. M a t e r i a l s a n d M e t h o d s
S i x - h u n d r e d $wisa-%Vebster, D B - F 1 h y b r i d or C-57 tnice, w e i g h i n g 15-:50 g, 1500 S y r i a n G o l d e n h a m s t e r s , w e i g h i n g 4 0 - 6 5 g, a n d 300 L o n g E v ~ n s or S p r a g u e - D a w l e y r a t s , w e i g h i n g 100-65 g, a n d 300 L o n g E v a n s or S p r a g u e - D ~ w l e y r~ts, xveigbAng 1 0 0 - 2 7 5 g, of e i t h e r sex, w~re u s e d o n l y o n c e i n a.n e x p e r i m e n t . T a b l e I lists d r u g s or m e t h o d s ~ l s e d to p r o d u c e t h e '~aeute r e v e r s i b l e lens o p a c i t y " . T h e d r u g d o s a g e s ~'ere t h e s a m e as g i v e n b y t~he o r l g i n a l stir, her. zNarcotics were a d m i n i s t e r e d s u b c u t a n e o u s l y while all o t h e r clrugs w e r e g i v e n irltrapcritoneal].3 .~. E n v i r o n m e n t a l ~%udie~ w e r e d o n e in ~ 47-1 c h a m b e r w i t h s u s p e n d e d a n i m a l r~elKs. T h i s was d e s i g n e d e s p e c i a l l y t0 c o n t r o l t e m p e r a t u r e , h u m i d i t y , a t m o s p h e r i c pressuxe a n d gas eoncent~rations a n d Was c o n s t r u c t e d b y R e s e a r c h I n s t r u m e n t Service, U n i v e r s i t y o f Oregon Medig~l School, :Por$land, Oregon. T h e ~niraal's eyeIids w e r e t a p e d o p e n or s h u t w i t h maslcLug %ape, O b s e r v a t i o n s w e r e earzied o u t for 120 r a i n a n d r e s u l t s t a b u l a t e d o n l y 19
20
F. T. F R A U N F E L D ] ~ I ¢
A N D R, P, B U R I ~ S
if t h e a n i m a l ~emained alive for a m i n i m u m of 90 rain. l~oreality rates were as h i g h as one-third a t extremes of temperature. Animals' eyes were e x a m i n e d before the experim e n t a n d a t 15-mL,~ intervals with a Haag-Streib biomleroscope requiring a 20-see removal from the e n v i r o n m e n t a l chamber. Cataracts were graded from 1 to 4 + (Fraunfelder a n d Burns, 1962, 19661. I n p o s t m o r t e m cxperiraents, a n i m a l s were killed b y cervical fracture i m m e d i a t e l y prior to use. A s p h y x i a experiments were done in a 3-1 desicc~tor j a r (]~iozzl, 1935; A m a n t e a , 19341 w i t h observation periods from 1 to 4 hr. Anoxia (Bellows and l~elson, 1944; Morone and Cieroni, 1950; Ca.ceia, Debarnot, Munilla and Russi, 19591 was produced b y placing rats in a 1-1 steel chamber and w i t h a v a c u u m p u m p s t i m u l a t i n g pressures of 30,000 to 40,000 f t T,,..Bl.,;s I
Methods of drugs which cause "acute reversible lens opacities" . . . .
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Anoxi~ (Bellows and Nelson, ]944; Mo~o:~o ~tncl Citroni, 1950: Caceia ct ttl., 1959) Asphyxia (]3iozzi, 1935: AmanteeL, 1934) Chloral h y d r a t e 4-0-60 mg/100 g. Cold (Trovor-Roper, 1957) ChloL~promazine ~ICI--Acutc Type (Smith, (_~avitb mtd t ~ a r m i n , 1!)(iG) :Death (Ooldmann ~ncl Rabinowitz, 19281 Dehydration (Goldmann anti ]gabinowitz, ] 928) Epinephrino and ergv.mine acid phosplmie (Turn Suden and ~,Vytnnn, 19401 70% :Ethyl alcohol 1 nil/100 g Isoproterenol :~IC! (Smith, Oavitt, and Kat~latm, 1963) Za~.x'artercnoi (Smibh et, el., 1963) .l~,,vorphanol (Smith ct el., 19631 /~Ianually hotding o pcrt eyelids (Goldmann and Rabinowit.z, ] 92S) Mepcridino RCI (Weirmt,vclr, Stewart and ]3ut~tcrworth, 1958) Mothadone ]['ICi (D/einstoc~ eb al.. 1958) Mocphine su|tkte (~Vcinstook et al., 1958) I?araldchyde 10 mg]100 .-. _~ Pentobarbi~al (l~raamfelder and Burns. I962) Triflupromazine !:[CI 15 rug/100 g. Stress (Soiye, 1,937)
above sea level. Animals were held a£ this le~'el from 30.-45 rain. l~z bot;h -moxit,. and a s p h y ~ a experiments 1~/o a~ropine sulfate eye drops were given 24 hr before the experiment, and prior to lolacing the anim~d in t h e cIm:mi)cr one eye was ta~cd shut. The fr.ont legs were hobbled w i t h tape so t h a t the a n i m a l c,)uld n o t remove the t.~Lpe from its lids. 8bress experiments were repeated as described £re~:iously (Selye, 19371 using adrenalin, morphine sulfi~_.te, f o r m a l d e h y d e and cold. Anterior chamber t e m p e r a t u r e measvxements were performed with 2000 ~2 resistance (+20~/a) glass-coated, bead-calibrated thermistors (Fcnwal :Electronics Company, )'ra~ai~gham, Mass.) a n d reotal temperatures were measured w i t h calibrated thermocouples (¥eUow Springs I n s t r u m e n t Company, Ino., Yellow Springs, Ohio.). 0 s m o l a r i t y of aqueous humor was tier'ermined in a nanoliter osmometer (Advance I~strunaen¢~, Inc., N e w t o n Highlands, Mass.) 3. Results
Definition a~d d~c~-i.~t~on of. the "acute reversible le~s opacity'" (1) E a c h m e t h o d u s e d t o p r o d u c e tJais c a t a r a c t i n t e r f e r e s w i t h n o r m a l lid m o v e m e n t ; (2) T h e c~$ara~t is of r a p i d onset, u s u a l l y s t a r t i n g w i t h i n a n h o u r ; (3) T h e c a t a r a c b is a superficial a n t e r i o r s u b c a p s u ] a r ]ens opacity" w h i c h b e g i n s a t ¢he a n t e r i o r lens sut~tres a n d s p r e a d s p e r i p h e r a l l y to i n v o l v e t h e e n t i r e superficial
AOU~DE REVERSIBLE
LENS
OI'AOITY
21
anterior cortical layer. I n addition certain drug,~ (morphine a n d epinephrine) m a y cause crescent-shaped opacities s t a r t i n g in the lower anterior portion of the lens early or Iate in the course of the cataract, whetlmr tim a n i m a l is prone or.supine; (4) W i t h all of the methods listed (except a t temperatm-es below 8°0) even t h o u g h the initiating stimulus is continued, these c a t a r a c t s wiU s t a r t to clear within a few tmurs, and all will completely clear ~fter the initiating stimulus is stopped; (5) D e v e l o p m e n t of the c a t a r a c t is prevented b y closure of the animal's eyelids. This t y p e of lens change was produced in mice, hamsters, rats, guinea l)igs~ rabbits and cats, p r i m a r i l y in v e r y young animMa of t]l(- larger species. The r a t e of onset, progression, and clearing of t.hcsc c a t a r a c t s v~ries with the m e t h o d of induction, species of anilual, and enviromnent. I n general, for smaller animals a t room temperat a r e ,~nd h u m i d i t y , the c a t a r a c t s s t a r t e d within 20 rain, reached a peak between 40 and 90 rain, and began to clear in 60-t- rain. The onset of the opacities occurs rapidly in young animals, sma.ll species, x d t h low t e m p e r a t u r e , low humidity, deep anesthesia., or with death. A t room t e m p e r a t u r e , in dead animMs the rect~I temperature decreased as much as 15°C, while in live animals, depending on the drug, temperature fell a, m ~ x i m u m of 10°C in a 2-hr observation period. There was no correlation between ~he m a x i m u m lens opacity and the tow point of rectal temperatuxe. The denser cataracts took longer to clear, although closure of the lids enhanced clearing. The usual mode of clearing was from the obnter peripherally, b u t occasionaIly randmn eccentric areas became t r m l s p a r e n t first. Direct pressure on the lens t h r o u g h the intn.ct cornea immediately clea~ed t h e c a t a r a c t in the area of contact. Keepil~g the eyelids open produced lens opacities, b u t proptosis of the globe or ocular manipulation necessary to shut the eye did n o t seem to influence lens opacification. Irrigatii~g the eye to w~sh a w a y the tear film and possibly enhance evaporation did not increase the frequency or degree of cataracts in hamsters. In live animMs, with t h e eyelids open a t high humidity, the corneal.lustcr, d e p t h of the anterior chamber and firmness of the eye were comparable to eyes mtder closed lids. Undez d e h y d r a t i n g conditions, however, t h e cornea developed exposure k e r a t o p a t h y , the depi;h of the a n ~ r i o r c h a m b e r was m a r k e d l y decreased, a n d the globe was s o f t . . ~ t low t e m p e r a t u r e , the depth of the a.uterior chamber generally varied w i t h the degree of cataract, the denser the c a t a r a c t the shallower t]m anterior chamber. H a m s t e r s dchydrat, ed b y intrapeNton.eal injections of 300/o urea and invert sugar, 60~/o aqueous m~a, 50~o aqueous mannitol, 4: ~ sucrose or saturaeed sodimn chloride solution developed bi6mica-oscopically different osmotic cataracts, evitieni; over the whole cortex, posteriB?ly as well as anteriorly, oce ,urring in equal degree under closed or opened eyelids.
Methods which caused or prevented the "acute ~'eversi5~ I~r~s opacity'" The c a t a r a c t was produced a t room t e m p e r a t u r e antl h u m i d i t y b y : (1) Drugs. AJl the agents in Table I cause lens opacities which fit the acute reversible lens opacity classification. I n addition to 1)reviously described agents, t h e injection of chloral hydrate, ethyl alcohol, p a r a l d e h y a e , a n d triflupromazine also caused t]ie~se changes. None in the closed eye series developed cataracts, either in Iive or in dead, over doscA animals. Some .drugs caused the animals to become stuporous, ~ d t k total l a c k of lid control, while with~ other agents the animals were active, b u t with markocl}y dimlmshed blink rates.. (2~ Mechanica~ Tvevention of lid clo~u~'e. Animals placed in ~ v e n t i l a t e d hblder with the eyelids t a p e d open developed cataracts. (3) Death..~mimals killed
22
F. T. F R A U N F E L D E R AND i%. P. BU1%NS
either b y cervical f r a c t u r e or drug overdosage developed lens opacities rapidiy if the eyelids were k e p t open. These clear if the dead animal's eyelids are closed. (4.) Er,dsio~, of ~he eyelids. In p r e - t e r m i n a l experiments, removal of the eyelids u n d e r local anesthesia caused cataracts. These c a t a r a c t s could be p r e v e n t e d b y placing over t h e open eye grease-sealed 0-5-ml glass cups, an air t i g h t layer of petroleum grease, vertical tubes containing isotonic solutions of salts or sugars, or specially fit plastic c o n t a c t lens which covered t h e entire cornea.
l~;n,d~,onznenld chamber Humidity a~wZtemperature. Since G o l d m a n n p o s t u l a t e d t h a t this type of c a t a r a c t in live or in d e a d animals was due to d e h y d r a t i o n , t h e effect of high or low h m n i d i t y on certain experimental cat0~ractsat r o o m temperatlu'e was studied in +~heenvironme~ital c h a m b e r (Table II). The percentage of eyes developing c a t a r a c t in high or low h u m i d i t y was compared for each m e t h o d of c a t a r a c t p r o d u c t i o n b y the X~ test. There w a s a statistically siomfificant increased frequency ( P = 0.1) of lens opacity in low h u m i d i t y as compared to high h u m i d i t y in ~,mimMs treated with m o r p h i n e SO~, pentobai'bitalethanol mixture, epinephrine with ergamine acid phosphate, and in animals immobilized w i t h o u t anesthesia. There were no significant difl'crel~ces in fl'equency of c a t a r a c t s produced b y low or high h u m i d i t y environme~~t with clflorpromazh~e, or death, while differences f o u n d with triflupromazine and epinephrine were ~ot signific a n t at t h e 5°/o level. All animals were stuporous except those given morphine ~: i h t e or levorphanof. These animals were active b u t had a diminished blink rate. None of the animals with lids t a p e d closed developed tens opacities. Some of t h e active animals were able to r u b t h e t a p e off between examinations, and these eyes were n o t included in t h e c e n t r e ! series. The combined effects of t e m p e r a t u r e and h u m i d i t y were studied on pe~toba.rbitalethanol anesthetized live hamsters (Table I l I ) and ha.m.~ters kil}ed b y cervica,I £raetlrre with open or closed lids (Tahle IV). :Decreasing t h e t e m p e r a t u r e increased t h e frequency and severity of c a t a r a c t s in all animals except the dead h a m s t e r s ma.intained a.t tow h u m i d i t y , where t e m p e r a t u r e changes had insigaificant effects, p~obably because t h e lenses were a l r e a d y opaque f r o m t h e blfluc~p . ~f low h u m i d i t y alone. Increasing the h u m i d i t y demreased the fl'equency a n d d e g r e e , , dlese c a t a r a c t s unless t h e temperatm:e w a s below 12°C. A t t e m p e r a t u r e s below 4°C, in animals k e p t w. h the eyelids open, in addition to t h e superficial tens changes, deep cortical a n d nuclear opacities were seen. I n the open eye "series t h e deep changes were covered b y t h e dense "acuf, e reversible lens o p a c i t y " t y p e change b u t these paxanuelea~ a n d nuclear opacities wer.e verified b y dissection. I n animals below 4°C, w i t h eyelids closed, only a n occasional early s,JperficiaI cortical o p a c i t y w a s seen while lid position h a d no appa.rent effect on t h e deep nuclear a n d parannclea~ opacities. Therefore, the superficial cortical opacity differs in location fix)m t h e deeper cold c a t a r a c t , altholNh cold increases f r e q u e n c y a n d seve~i W of the " a c u t e reversible tens opacity'" type change. Closure of t h e eyelids m a r k e d l y impeded t h e fomnation of t h e " a c u t e reversible lens o p a c i t y " tyR3e changes, nob t h e cold cataract, and b h m t pressure on the lens through the intact corneal clears this type lens changes, b u t n o t t h e cold catarac~ (Table V). Otherfacoyrs. The " a c u t e reversible lens o p a c i t y " develops in complete d a r k n e s s
Mice
Levorphauol (2.8 rag/100 g) Chlor~romt~zine H01 (10-!5 rag/100 g) Morphine sulfate (20q00 rag/100 g) Immohiliza'~ion without, anesthesia Trifluprom~zine HC[ (15 rag/100 g) Epinopkrino (0.5--1.0 mgll00 g) Pcnt~barbit~d-ettumol mixture (1 .rrd]lO0g) Epinepltrine (0'2-1-0 rag/100 g) and ergamine acid phosphate (20-100 rag/100 g)
%
High Low
11[igh Low High Low ttigh Low High Low High Low High Low High Low High Low 20 24
20 20 GO 65 33 44 70 28 20 26 20 21 24 22 42 20 1 14
20 20 50 56 14 19 30 23 9 22 4 9 9 14 13 ]9 5 5g
100 100 83 86 42 43 43 $2 "45 85 20 43 :18 64 31 95 0.1 1.6
2.4 3.5 1"7 2.2 0'6 1.0 0-7 2.1 0.5 2"7 0.3 1.2 0.4 1-8 0.3 2.2
10 1,i
44 20
21 30 28
24 44 24 28 20 26 20
20 33 28
20
0 0
0 0 0
0 0
0 0 0 0
0 0 0 0 0 0 0 0 0
0
0 0 0 0 0 0 '0 o 0 0
0 0
Av.* opacity
0
0 0
No. of eyes of eyes 12clative No. of developing with Max, No, ~o, of humidity of eycz cataracts cataract,o, opaeit,y of eyes cataracts
Eyolkls closed
High huraidity 9 5 - %. Low humidity below 15%. Temperature 23-26°C, * The mazimum ayerago opacity for each group is the smrl of the dense~ grade of tens ol)aeiLy in each a~fima], divided hy the total number of eye~.
Rats
Hamsters
Mice
Mice
Hamsters
Mice
Mice
Hamstcrs
A,fiiaml
Deattl
:Method of eat~raet production
'eversibte tens opacities"
Eyelids open
Effect of high a. ut low hum.idity on "acute
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Tempera.tu,'o
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0-4°0
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Random
t~ol~tive humidi~y
.
35--60°(] 23-26~C 8-t2'C
.
Low (balow 15%)
.
35-40<'C .,,-~'s~ q~oo,~ 8-12~0
::
High (95+%)
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Eyelids open
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20
]2 19 -0
,i i~ 31
IO0
130 95 ~0o
6 31 91
3'3
l.f~ 2.2 3.4
0.1 0.3 3"5
24
20 44 ~0
25 20 28
of eyes of eyes Mt~x, developblg witch av. h'o, of cataracts cataracts opaeit,y eyes
.
* Par~muotc~r and ~luclear opaeitlca
26
.90 20 20
65 42 34
No, of eyes
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%
Eyelids etched
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0 0 1
0 0 5
83
0 0 5
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1-8'
0 0 0.I
0 0 0"3
of eyes of eye~ Max. developing with av. cataracts oataract~ opacity
_ _
Bffects of humidity and te.',,?crat.re on "acute reversible lens o~aci~ies in a~,e,'theti~d hamsters _
Random
(bolow15%)
Low
(95+%)
}_Iigh
P~lative humidii>y
20
22 20 22
3~-40¢C 23-26°C 8-12¢C 0-4°C
22 20 22
20
22 20 20
I0 20 22
I00
190 I00 91
46 i00 i00
4.0
3"~ 3"5 3.4
0-5 2.4 4.0
Parannele~rand nuclearopacities.
N~,of eyes
35-40~0 2336°0 8-12~0
Temperature
20
20 20 20
20 20 20
0 0 IO I00
20
0 0 IO 0 0 ~
0 0 2
3,6*
0 0 O-I
0 0 0.I
Eyelids open •ydid8 dosed No, % No. % of eyes of eyes M,~:, of eyes of ~yes ~lax. d~velopi~g with av. ~o. of developing wi~b~ a~. cataracts cataracts opacity eyes cataracts eataraeVz opacif,y
Effects of hv.m~4ity and to.~pc'rature on, "acute .reversible &:nsopacities" in deag l~a.msters
'/'asL~ IV
26
F . T. F R . A U N F E L D E R
AND
II. :P. t ~ U I t N 8
and is unaffected by daily barometric laboratory changes: Lens opacities develop equally in hamsters anesthetized or ki|led by cervical fracture when exposed to atmospheres of air, 100% 0~, I 0 0 % CO 2, 100% N~, or 90% 0 ~ - - 1 0 % COz, T A 13LF. V
Differences in "acute reversible le~s opacities" and cold eataract~ in hamsters "Acu¢~ ro~er~ibie lena opacities" Location o f cat, ar~,ct
Anterior subcapsular
"Cold" cataract Deep cortical or
nuclear Influence of ton~perature
Increases with low t e m p e r a t,m'e
l l a r e l y occurs a b o v e 5"C
Lid closure
Prevent~ opacity
N o effect
Cataract, c|eara in jnitia~ing c ~ v i r o n m e n t
Yes
No
Pressure on lens through intact, eorne~
Clears o p a c i t y ilx aFe~
No effceL
Of pr~s!ittll'O
Refractile bodies Small brownish refractile bodies wlfich a p p e a r biomicroscopically as changes in the lens c~psuIe shagreen were seen in anesthetized h a m s t e r s at 4-12¢C a n d in dead animals below 4°C. With dead h a m s t e r s k e p t at ,'oom t e m p e r a t u r e and high humidit,;,. 54°,/0 of eyes in an environment of 90~/o O o - 10~/o C0e a n d 9 % of eyes in 100% 0., showed these refraetite lens changes, which were not seen in CO., or N 2 atmospheres. The refractile bodies were more frequent in live animals and in the closed eyelid series. Histology a.~d osmolarity No histologic abnornaalJ~" was noted in cataractous lenses of eyes removed during various stages of cataract development, fixed in C~rnoy's solution or 10% form~din, and stained with periodic acid-Schiff, hemutox3rlin-eosin, or triohro me stai ns. EIectron microscopic and biochemical studies will be reported elsewlaerc. Comparison of anterior chamber aqueous osmolarity in hamsters with one eye open, the other eye closed, are shown in Table VI. I n live animals u n d e r room conditions no difference was found with 1 to 2 + lens changes. Wit.h 3 or 4 + lens changes a statisticMly significant increase in aqueous osmolari~y was found in the open c a t a r a c t o u s eye. This was especially true in eyes pre-treated with 10% phenylephrine which causes increased drying effects. I n dead animals regardless of the degree of lens chat~g~ there was an increase in aqueous osmolarity in the e.~posed eye even a t 95~o relative humidity. Comparison of normal right and left eyes showed no significant differences in aqueous osmolarity. Anoxia, asphyxia a.nd stress "~Vhen anoxia was induced in r a t s h d closure in iive auimals totally prevented lens changes (Table VII). Lens opacity developed in only one of 34 eyes in dead animals.
Normal cmltrols Rigk~ eye eompar~ lef~
/geml Cervical fracture
23-26°C 30-80%
23-26°C 95%
5
16 11 5
6
Wit,h I0% phenylephrhao eTe drops at s~ar£ of e.xperitrtci~'~
5 5 6
5
23-26°C 30-40% 6
0
369
383 455 453
620
467
372 442 467
Miiliesmoles ~
Right eye
0 1 "t2 to 3 +
4+
4+
1 ~o 2 + 3+ 4-]-
~No, Degree altinlEtls ea.tarac~
With 1% atropt~lc eye drops ~4 '~ hr earlier
A~ive Pontobarh{tal ETOH mixburc wit.hou~eye drng.~
hiebhod
Temperature and relst.ive humidi~,y
Right eye open
0
0 0 0
0
0
0 0 0
346 379 342
392
366
323 399 397
moles "~o
Miliios-
365
Left eye
c~tarae~
Degree
L~ft, eye dozeA
A,n,terior chamber aqueous osmolari y--hamsters
+4
+ 37 + 74 -I-63
+230
+101
+{-18 +47 +69
Differeaees
0-4
0.001 0.001
0.00I
0-001
0.4 O.O01 0-901
Prob. ~biLi~y
28
IV. "£. F R A U N F E L I ) l g I ~
AND
1%. 1~. : B U R N S
This possibility could h a v e been due to incomplete lid closure. Closure of the eyelids did n o t totally p r e v e n t c a t a r a c t f o r m a t i o n u n d e r asphy-xic conditions. F o u r early at.age c a t a r a c t s were fotmd in 26 eyes in the live animals, and i1 of 21 eyes in dead :I?a~5= V I I
Effect, of lid position on cr~taracts induced by anoxia amd asp/~yxia Live rats Eyelids open No. of eyes
No. of cataracts
])ead rags
Eyelids closed No, of eyes
No. of eatar,~ets
Eyelids open No. of eyes
Eyelids closed
No. of cataracts
No, of eyes
No. of cataraet.s
Anoxia
IS
9
12
0
32
27
34
1
A s p h 5 .-xir~
26
20
26
4
21
15
21
I1
animals u n d e r closed lids. The live mfimMs wh.;ch developed lens changes under closed lids were in p r e - t e n n i n a l asphyxic state. No c a t a r a c t s were found under closed Iids in a n i m a l s subjected to stress, exceptfor 1 + lens changes in 10~'o of animals k e p t ag low t e m p e r a t u r e for over -48 hr. 4. D i s c u s s i o n
The m a j o r stimulus for the " a c u t e reversible lens o p a c i t y " type changes appears to be mediated through the cornea, since lid. elosm'e, a corneal cont'~ct lens. or a.:: airt i g h t cuI) over the open eye prevents d e v e l o p m e n t of c a t a r a c t s w i t h a n y method used. Since the initial cal.aract is limited to tire pupillury area., ghi:.~ also suggests trans-corneal factors att~cthlg the a~terior c h a m b e r aqueous h u m o r and, in turn, the lens. Since ion exchange occurred only in t h e sm'face of t.he lens, equilibrium being a t t a i n e d r a p i d l y ~ i t h the suxrounding aqueous (PMm, 1948), t.he loss of lens transp a r e n c y was anterior subcapsular. E v a p o r a t i o n of w a t e r t h r o u g h the cornea, concentrating the aqueous, in turn affecting t h e lens has been suggested as the cause of d e h y d r a t i o n and a.eute pos~ m o r t e m c a t a r a c t s (Goldmamt a n d l%abinowitz, 1928). Our results eonf~rm evaporation as t h e p r l m a r y cause of m a n y of the~e c a t a r a c t s since Ligh humidi W p r e v e n t e d or m a r k e d l y irdfibited lens opacities a t room t e m p e r a t u r e Mong w i t h the increased osmolarity of t;he aqueous. However, other factors m a y be operative since high h u m i d i t y did n o t significantly p r e v e n t the lens opacities due to tevorphanol, c h l o f promazine, low t e m p e r a t u r e a n d c a t a r a c t s developh~g i m m e d i a t e l y a f t e r death, although lid closure did. Significant lens changes were found in post morcem experiments ag 90 n- )/o reb~tive h u m i d i t y a t all t e m p e r a t u r e levels where e v a p o r a t i o n shotdd not be a m a j o r factor. I n c r e a s e d aqueous osmola~ity was f o u n d in t h e open eye even if no c a t a r a c t deveIoped. ~,Vhy this should occur is unknown. A p a r t i a l explanation for lens changes in dead animals is t h e decreased metabolic r a t e secondary to 10-15°0 drop in boyd ~emperar a r e since decreasing t h e a m b i e n t t e m p e r a t u r e increases t h e incidence a n d degree of cat~rao~sregardless of h u m i d i t y i~ live or d e a d animMs (Tables I I I a n d IV). Therefore,
ACUTE I~EVEI~SIBLE LENS O P A C I T Y
29
t h e r e are intErrElationships o f v a r i o u s factors, especially tempero~ture ~nd h u m i d i t y , affecting t h e lens t r a n s p a r e n c y . Since nourislm~ent of t h e lens i.~ t o t a l l y d e p e n d e n t orl t h e aqueous, a n y m e t h o d w h i c h decreases a q u e o u s p r o d u c t i o n , e.g. general a n e s t h e s i a , cold, s y m p a t h o m i m e t i c agents, v a s o c o n s t r i c t i o n or shook, m a y p o t e n t i a t e a tra ns-coroeal ( t e h y d r a t i u g stimulus. Topical p h e n y t e p h r i n e m a r k e d l y e n h a n c e s t h e s e c a t a r a c t s a n d also causes bhc d r i e s t ,~nterior segment, shallowest, a n t e r i o r c h a m b e r s a n d t h e g r e a t e s t aqueous c o n c e n t r a t i o n . T h i s s u p p o r t s t h e i m p o r t a n c e ok" a q u e o u s h u m o r p r o d u c t i o n in this t y p e of lens opacit.y (~Vcins~ock a n d S t e w a r t , 1961:,. I n v i c e cold cataract, s a p p e a r to be o£ t w o typed, Vhe " a c u t e reversible lens o p a e i t y " a n d t h e p a r a n u c t c a r a n d nuclEa~ " c o l d " c a t a r a c t : ~ l t h o u g h t h e effect of lid position ou " e o ( d " c a t a r a c t s h a d r e c e n t l y been recognizcd. (Klass a n d B u r n s , 1964), CItE diffe, rchrist, ion of two d i s t i n c t t y p e s was n o t noted. The t r u e cold c a t a r a c t m a y bc due to p r e c i p i t a t i o n of g ~ m m a c r y s t a l l i n (Zigntan a n d L e r m a u , 1965). P r e s e n t d a t a indicates anoxia, c a t a r a c t s fit in t h e " a c u t e reversible lens o p a c i t y " classification, while results w i t h a s p h y x i a are less clear cut. Stress generate(1 c a t a r a c t s also can be p l a c e d in the s a m e group, except ia t h e long t e r m h y p o t h e r m i a e x p e r i m e n t s . Brownish, refractile bodies o£ t h e lens h a v e been n o t e d also by T r o v e r - R o p e r , who fcl~ these were p i g m e n t g r a n u l e s ( T r o v e r - R o p e r , 1957), b u t tl~eir t r a n s i e n t n a t u r e a n d t h e i r biomic~-oscopie appe~rances m a k e tlxis seem u n l i k e l y . T r a n s i e n t lens c h a n g e s have r e c e n t l y been described in p r e m a t u r e irffants ( M c C o r m ick 1968). These are posterior s u b c a p s u l a r a n d p e r s i s t from 10 to 1S d a y s a n d seem to h a v e n o correlatio~t to the ions cha~ges described herE. G o l d m a n n , who first described ~he effect of lid positio~ on curt, s i n lens changes, st,~tccl, " I f incorrect decisions in cataract, research are avoided, t~he purpose of this p a p e r is s e r v e d " . This s t a t e m e n t is as true t o d a y as it was w h e n m a d e a h n o s t o n e - h a t / c e n t u r y ago, ACI(NO~V L1£ D G ~ I E N T S The assistance of Mrs L. Willenberg and Miss R,. Warren a n d the advice from Dr Calvin H a n n a is gratefully acknowledged. This work was supported in part by U.S. Public H e a l t h Training G r a n t NB-5042-10, NB-10041-432 ant] Service G r a n t NB0-4770-03 from the National I n s t i t u t e of Neurological Diseases and Blindness, U.S. Public tIea lth Service. REFERENCES
Amante~,, G. (1934:). Atti Accad. Naz. ~ : ~ e l Rer~l. Clause ,~c.i. Fis. :][at. Nat. 20, 220. Bellows, J. and Nelson, ]D. (1944). Arch. Ophthalmol. (Chicago) 31,250. Biozzi, (3. (1935). Arch. Ophthab~ol. (Berlin) 133, 423. Caceia, A. IL., Debarnot,, )~. 0., hhmilla, L. G. and Russi, I. T. (1959). Semana '.lied. (Buenos Aires) 115, 751. Fraunfeider, F. T. and Burns, R. P. (1962). Prec. See. Eccp. Biol. ~fed. 110, 72. Fratmfelder, F. T. and ]3ttr~s, R. P. (1966). Arch. Ophlhatnwl. (Ohicago) 76, 599. Goldmann, H. and I~abino~,qtz, G. (1928). Kl.in. 2tgonat~bl. Auqenheitk. 81,771. Klass, A. 5[. and Burns, ~. ~.. (1964). Exptl Eye Jr~e~. 3, 213. ~IeCorraiok, A. Q. (1968). Can. d. Ophthal.mol, 3, 202. ~[orone, G. ~nd Citron.i, ~I. (k950)..Riv. ,lIexl. Aeror~, Spaz. 13, 655. Palm, E. (1948). Acts O?7~thatmol. 26 (Suppl. 32), t, 8elye, H. (1937). Endoc, rino~ogy 219 169. Smith, A. A., Gayltt, ft. and K~plan, !~[. (1963). Retort Advart. Biol. Psychiat. 6~ 208. Smith A. A., Ggvitt, g. and Karmin, ,~. (1966). Arch. Ophthalmol. (Ohicaffo) 75;~ 99.
3O
F. T. F R A U N F E L D E R 2~ND R. P. BURNS
Trevor-Roper, P', D. (1957). Tra~.~. Ophthal.mol. ,~oc. U.K. 77, 401. Turn Suden, C. and Wyl.nau, L. C. (1940). Endocri~mlogy 17, 628. Weinstock, M., Stewart, H. C. and Butterworth, K. 1%. (1958). Nalure 182, 1519. Weinstock, M. and Stewart, H. C. (1961). Brit. J. Optt~kalmoI. 45~ 408. Zigmc~n, S. and Lerman, S. (1965). Ea':ptl ,Eye Res. 4~ 24.
Acute Reversible Lens Opacity: Caused by Drugs, Cold, Anoxia, Asphyxia, Stress, Death and Dehydration F . T. F R A U N F E L D E I ~ ~ N D 1=[. IL BUI~NS
Depa~,tme,nt of Oplsthaln~ology, University[ of Oregon Med iex~l School,. Port,land, Ore. 9720~, ',U.S.A, and,
D iv'i.~ion of Ophthnlmology, U~,ive,rsi~,y of Arkansas Aledical School, Little Rock, A r k . 72201, U.S.A. (Received 26 Noven~ber 19~9, Boston) Acq~te experimental lens opacities reported to be caused by narcotics, phenoghi~zines, ¢::pi:~ephrine, anoxia, and certain types of lens opacities induced by death, asphyxia, cold or s t r c ~ are prevented by closure of the animal's eyelids. An unawareness of the imporLance of eyelid position has ted to confimion cJoncerning the pathogenesis of m a n y of these lens changes, l~ost o£ these experimental c~taract~ e~n be classified into a si:aglo gro~p ~vith commo~x chaxaot6ris$ics, for which we propose the term "~eut~ reversible lens opacity". The opacity is a reversible loss of tr~rmpare~ey of $he superficial anterior leas cortex which is prevented by closure of the eyelids. This type of ¢attrract m a y be produced by mechanical methods or agents which interfere w i t h lid closure or depress the blir~k reflex. The lens op~cit,y m a y regress eve:~ tho~gh the initiating stimulus is maintained. Although dehydration of the aqueous h u m o r and lens is the most i m p o r t a n t factor in development of the lens tra~mp~rency change, there ave other factors which also play ~ role. l. Introduction
I n 192S a c u t e r e v e r , s i b l e loss o f l e n s t r a n s p a r e n c y in l i v e or d e a d r a t s w a s r e p o r t e d b y hold;.ng o p e n t h e e y e l i d s m a n u a l l y . N o c a t a r a c t s d e v e l o p e d if t h e a n_imaFs e y e l i d s w e r e cto..qed ( G o l d n s ~ m n ,~nd :R.~tbinowi~z, 1928). W e f o u n d t l m ~ r n a u y p r e v i o u s l y r e p o r t e d acute, e x p e r i m e n t a l c a t a r a c t s p r o d u c e d b y v a . r i o u s d r u g s could[ b e p r e v e n t e d by simply closing the animal's eyelids, and the concept of "a.c~te reversible lens o p a c i t y " w a s i r t t r o d u c e d %0 d e s c r i b e t h i s p h e n o m e n o n ( F r a u n f e l d e r an(] :Burns, 1966). Tim p~Lrpose o f thSs p a p e r is to d e f i n e a n d r e c l a s s i f y m a n y p r e v i o u s l y d e s c r i b e d e x p e r h u e n t a l l e n s c,A a n g e s i n t o o n e g r o u p , t o d e s c r i b e t h e e f f e c t of e n v i r o n m e l l t , al c h a n g e s on t M s t y p e l e n s c h a n g e , a n d t o d e f i n e m o r e d e ~ r l y t h e i n v i c e c o l d c a t a r a c t , 2. M a t e r i a l s a n d M e t h o d s
S i x - h u n d r e d $wisa-%Vebster, D B - F 1 h y b r i d or C-57 tnice, w e i g h i n g 15-:50 g, 1500 S y r i a n G o l d e n h a m s t e r s , w e i g h i n g 4 0 - 6 5 g, a n d 300 L o n g E v ~ n s or S p r a g u e - D a w l e y r a t s , w e i g h i n g 100-65 g, a n d 300 L o n g E v a n s or S p r a g u e - D ~ w l e y r~ts, xveigbAng 1 0 0 - 2 7 5 g, of e i t h e r sex, w~re u s e d o n l y o n c e i n a.n e x p e r i m e n t . T a b l e I lists d r u g s or m e t h o d s ~ l s e d to p r o d u c e t h e '~aeute r e v e r s i b l e lens o p a c i t y " . T h e d r u g d o s a g e s ~'ere t h e s a m e as g i v e n b y t~he o r l g i n a l stir, her. zNarcotics were a d m i n i s t e r e d s u b c u t a n e o u s l y while all o t h e r clrugs w e r e g i v e n irltrapcritoneal].3 .~. E n v i r o n m e n t a l ~%udie~ w e r e d o n e in ~ 47-1 c h a m b e r w i t h s u s p e n d e d a n i m a l r~elKs. T h i s was d e s i g n e d e s p e c i a l l y t0 c o n t r o l t e m p e r a t u r e , h u m i d i t y , a t m o s p h e r i c pressuxe a n d gas eoncent~rations a n d Was c o n s t r u c t e d b y R e s e a r c h I n s t r u m e n t Service, U n i v e r s i t y o f Oregon Medig~l School, :Por$land, Oregon. T h e ~niraal's eyeIids w e r e t a p e d o p e n or s h u t w i t h maslcLug %ape, O b s e r v a t i o n s w e r e earzied o u t for 120 r a i n a n d r e s u l t s t a b u l a t e d o n l y 19
20
F. T. F R A U N F E L D ] ~ I ¢
A N D R, P, B U R I ~ S
if t h e a n i m a l ~emained alive for a m i n i m u m of 90 rain. l~oreality rates were as h i g h as one-third a t extremes of temperature. Animals' eyes were e x a m i n e d before the experim e n t a n d a t 15-mL,~ intervals with a Haag-Streib biomleroscope requiring a 20-see removal from the e n v i r o n m e n t a l chamber. Cataracts were graded from 1 to 4 + (Fraunfelder a n d Burns, 1962, 19661. I n p o s t m o r t e m cxperiraents, a n i m a l s were killed b y cervical fracture i m m e d i a t e l y prior to use. A s p h y x i a experiments were done in a 3-1 desicc~tor j a r (]~iozzl, 1935; A m a n t e a , 19341 w i t h observation periods from 1 to 4 hr. Anoxia (Bellows and l~elson, 1944; Morone and Cieroni, 1950; Ca.ceia, Debarnot, Munilla and Russi, 19591 was produced b y placing rats in a 1-1 steel chamber and w i t h a v a c u u m p u m p s t i m u l a t i n g pressures of 30,000 to 40,000 f t T,,..Bl.,;s I
Methods of drugs which cause "acute reversible lens opacities" . . . .
~
I
L
~
I
l
l
- -
__
.
::
:
:
--
:
I
]
Anoxi~ (Bellows and Nelson, ]944; Mo~o:~o ~tncl Citroni, 1950: Caceia ct ttl., 1959) Asphyxia (]3iozzi, 1935: AmanteeL, 1934) Chloral h y d r a t e 4-0-60 mg/100 g. Cold (Trovor-Roper, 1957) ChloL~promazine ~ICI--Acutc Type (Smith, (_~avitb mtd t ~ a r m i n , 1!)(iG) :Death (Ooldmann ~ncl Rabinowitz, 19281 Dehydration (Goldmann anti ]gabinowitz, ] 928) Epinephrino and ergv.mine acid phosplmie (Turn Suden and ~,Vytnnn, 19401 70% :Ethyl alcohol 1 nil/100 g Isoproterenol :~IC! (Smith, Oavitt, and Kat~latm, 1963) Za~.x'artercnoi (Smibh et, el., 1963) .l~,,vorphanol (Smith ct el., 19631 /~Ianually hotding o pcrt eyelids (Goldmann and Rabinowit.z, ] 92S) Mepcridino RCI (Weirmt,vclr, Stewart and ]3ut~tcrworth, 1958) Mothadone ]['ICi (D/einstoc~ eb al.. 1958) Mocphine su|tkte (~Vcinstook et al., 1958) I?araldchyde 10 mg]100 .-. _~ Pentobarbi~al (l~raamfelder and Burns. I962) Triflupromazine !:[CI 15 rug/100 g. Stress (Soiye, 1,937)
above sea level. Animals were held a£ this le~'el from 30.-45 rain. l~z bot;h -moxit,. and a s p h y ~ a experiments 1~/o a~ropine sulfate eye drops were given 24 hr before the experiment, and prior to lolacing the anim~d in t h e cIm:mi)cr one eye was ta~cd shut. The fr.ont legs were hobbled w i t h tape so t h a t the a n i m a l c,)uld n o t remove the t.~Lpe from its lids. 8bress experiments were repeated as described £re~:iously (Selye, 19371 using adrenalin, morphine sulfi~_.te, f o r m a l d e h y d e and cold. Anterior chamber t e m p e r a t u r e measvxements were performed with 2000 ~2 resistance (+20~/a) glass-coated, bead-calibrated thermistors (Fcnwal :Electronics Company, )'ra~ai~gham, Mass.) a n d reotal temperatures were measured w i t h calibrated thermocouples (¥eUow Springs I n s t r u m e n t Company, Ino., Yellow Springs, Ohio.). 0 s m o l a r i t y of aqueous humor was tier'ermined in a nanoliter osmometer (Advance I~strunaen¢~, Inc., N e w t o n Highlands, Mass.) 3. Results
Definition a~d d~c~-i.~t~on of. the "acute reversible le~s opacity'" (1) E a c h m e t h o d u s e d t o p r o d u c e tJais c a t a r a c t i n t e r f e r e s w i t h n o r m a l lid m o v e m e n t ; (2) T h e c~$ara~t is of r a p i d onset, u s u a l l y s t a r t i n g w i t h i n a n h o u r ; (3) T h e c a t a r a c b is a superficial a n t e r i o r s u b c a p s u ] a r ]ens opacity" w h i c h b e g i n s a t ¢he a n t e r i o r lens sut~tres a n d s p r e a d s p e r i p h e r a l l y to i n v o l v e t h e e n t i r e superficial
AOU~DE REVERSIBLE
LENS
OI'AOITY
21
anterior cortical layer. I n addition certain drug,~ (morphine a n d epinephrine) m a y cause crescent-shaped opacities s t a r t i n g in the lower anterior portion of the lens early or Iate in the course of the cataract, whetlmr tim a n i m a l is prone or.supine; (4) W i t h all of the methods listed (except a t temperatm-es below 8°0) even t h o u g h the initiating stimulus is continued, these c a t a r a c t s wiU s t a r t to clear within a few tmurs, and all will completely clear ~fter the initiating stimulus is stopped; (5) D e v e l o p m e n t of the c a t a r a c t is prevented b y closure of the animal's eyelids. This t y p e of lens change was produced in mice, hamsters, rats, guinea l)igs~ rabbits and cats, p r i m a r i l y in v e r y young animMa of t]l(- larger species. The r a t e of onset, progression, and clearing of t.hcsc c a t a r a c t s v~ries with the m e t h o d of induction, species of anilual, and enviromnent. I n general, for smaller animals a t room temperat a r e ,~nd h u m i d i t y , the c a t a r a c t s s t a r t e d within 20 rain, reached a peak between 40 and 90 rain, and began to clear in 60-t- rain. The onset of the opacities occurs rapidly in young animals, sma.ll species, x d t h low t e m p e r a t u r e , low humidity, deep anesthesia., or with death. A t room t e m p e r a t u r e , in dead animMs the rect~I temperature decreased as much as 15°C, while in live animals, depending on the drug, temperature fell a, m ~ x i m u m of 10°C in a 2-hr observation period. There was no correlation between ~he m a x i m u m lens opacity and the tow point of rectal temperatuxe. The denser cataracts took longer to clear, although closure of the lids enhanced clearing. The usual mode of clearing was from the obnter peripherally, b u t occasionaIly randmn eccentric areas became t r m l s p a r e n t first. Direct pressure on the lens t h r o u g h the intn.ct cornea immediately clea~ed t h e c a t a r a c t in the area of contact. Keepil~g the eyelids open produced lens opacities, b u t proptosis of the globe or ocular manipulation necessary to shut the eye did n o t seem to influence lens opacification. Irrigatii~g the eye to w~sh a w a y the tear film and possibly enhance evaporation did not increase the frequency or degree of cataracts in hamsters. In live animMs, with t h e eyelids open a t high humidity, the corneal.lustcr, d e p t h of the anterior chamber and firmness of the eye were comparable to eyes mtder closed lids. Undez d e h y d r a t i n g conditions, however, t h e cornea developed exposure k e r a t o p a t h y , the depi;h of the a n ~ r i o r c h a m b e r was m a r k e d l y decreased, a n d the globe was s o f t . . ~ t low t e m p e r a t u r e , the depth of the a.uterior chamber generally varied w i t h the degree of cataract, the denser the c a t a r a c t the shallower t]m anterior chamber. H a m s t e r s dchydrat, ed b y intrapeNton.eal injections of 300/o urea and invert sugar, 60~/o aqueous m~a, 50~o aqueous mannitol, 4: ~ sucrose or saturaeed sodimn chloride solution developed bi6mica-oscopically different osmotic cataracts, evitieni; over the whole cortex, posteriB?ly as well as anteriorly, oce ,urring in equal degree under closed or opened eyelids.
Methods which caused or prevented the "acute ~'eversi5~ I~r~s opacity'" The c a t a r a c t was produced a t room t e m p e r a t u r e antl h u m i d i t y b y : (1) Drugs. AJl the agents in Table I cause lens opacities which fit the acute reversible lens opacity classification. I n addition to 1)reviously described agents, t h e injection of chloral hydrate, ethyl alcohol, p a r a l d e h y a e , a n d triflupromazine also caused t]ie~se changes. None in the closed eye series developed cataracts, either in Iive or in dead, over doscA animals. Some .drugs caused the animals to become stuporous, ~ d t k total l a c k of lid control, while with~ other agents the animals were active, b u t with markocl}y dimlmshed blink rates.. (2~ Mechanica~ Tvevention of lid clo~u~'e. Animals placed in ~ v e n t i l a t e d hblder with the eyelids t a p e d open developed cataracts. (3) Death..~mimals killed
22
F. T. F R A U N F E L D E R AND i%. P. BU1%NS
either b y cervical f r a c t u r e or drug overdosage developed lens opacities rapidiy if the eyelids were k e p t open. These clear if the dead animal's eyelids are closed. (4.) Er,dsio~, of ~he eyelids. In p r e - t e r m i n a l experiments, removal of the eyelids u n d e r local anesthesia caused cataracts. These c a t a r a c t s could be p r e v e n t e d b y placing over t h e open eye grease-sealed 0-5-ml glass cups, an air t i g h t layer of petroleum grease, vertical tubes containing isotonic solutions of salts or sugars, or specially fit plastic c o n t a c t lens which covered t h e entire cornea.
l~;n,d~,onznenld chamber Humidity a~wZtemperature. Since G o l d m a n n p o s t u l a t e d t h a t this type of c a t a r a c t in live or in d e a d animals was due to d e h y d r a t i o n , t h e effect of high or low h m n i d i t y on certain experimental cat0~ractsat r o o m temperatlu'e was studied in +~heenvironme~ital c h a m b e r (Table II). The percentage of eyes developing c a t a r a c t in high or low h u m i d i t y was compared for each m e t h o d of c a t a r a c t p r o d u c t i o n b y the X~ test. There w a s a statistically siomfificant increased frequency ( P = 0.1) of lens opacity in low h u m i d i t y as compared to high h u m i d i t y in ~,mimMs treated with m o r p h i n e SO~, pentobai'bitalethanol mixture, epinephrine with ergamine acid phosphate, and in animals immobilized w i t h o u t anesthesia. There were no significant difl'crel~ces in fl'equency of c a t a r a c t s produced b y low or high h u m i d i t y environme~~t with clflorpromazh~e, or death, while differences f o u n d with triflupromazine and epinephrine were ~ot signific a n t at t h e 5°/o level. All animals were stuporous except those given morphine ~: i h t e or levorphanof. These animals were active b u t had a diminished blink rate. None of the animals with lids t a p e d closed developed tens opacities. Some of t h e active animals were able to r u b t h e t a p e off between examinations, and these eyes were n o t included in t h e c e n t r e ! series. The combined effects of t e m p e r a t u r e and h u m i d i t y were studied on pe~toba.rbitalethanol anesthetized live hamsters (Table I l I ) and ha.m.~ters kil}ed b y cervica,I £raetlrre with open or closed lids (Tahle IV). :Decreasing t h e t e m p e r a t u r e increased t h e frequency and severity of c a t a r a c t s in all animals except the dead h a m s t e r s ma.intained a.t tow h u m i d i t y , where t e m p e r a t u r e changes had insigaificant effects, p~obably because t h e lenses were a l r e a d y opaque f r o m t h e blfluc~p . ~f low h u m i d i t y alone. Increasing the h u m i d i t y demreased the fl'equency a n d d e g r e e , , dlese c a t a r a c t s unless t h e temperatm:e w a s below 12°C. A t t e m p e r a t u r e s below 4°C, in animals k e p t w. h the eyelids open, in addition to t h e superficial tens changes, deep cortical a n d nuclear opacities were seen. I n the open eye "series t h e deep changes were covered b y t h e dense "acuf, e reversible lens o p a c i t y " t y p e change b u t these paxanuelea~ a n d nuclear opacities wer.e verified b y dissection. I n animals below 4°C, w i t h eyelids closed, only a n occasional early s,JperficiaI cortical o p a c i t y w a s seen while lid position h a d no appa.rent effect on t h e deep nuclear a n d parannclea~ opacities. Therefore, the superficial cortical opacity differs in location fix)m t h e deeper cold c a t a r a c t , altholNh cold increases f r e q u e n c y a n d seve~i W of the " a c u t e reversible tens opacity'" type change. Closure of t h e eyelids m a r k e d l y impeded t h e fomnation of t h e " a c u t e reversible lens o p a c i t y " tyR3e changes, nob t h e cold cataract, and b h m t pressure on the lens through the intact corneal clears this type lens changes, b u t n o t t h e cold catarac~ (Table V). Otherfacoyrs. The " a c u t e reversible lens o p a c i t y " develops in complete d a r k n e s s
Mice
Levorphauol (2.8 rag/100 g) Chlor~romt~zine H01 (10-!5 rag/100 g) Morphine sulfate (20q00 rag/100 g) Immohiliza'~ion without, anesthesia Trifluprom~zine HC[ (15 rag/100 g) Epinopkrino (0.5--1.0 mgll00 g) Pcnt~barbit~d-ettumol mixture (1 .rrd]lO0g) Epinepltrine (0'2-1-0 rag/100 g) and ergamine acid phosphate (20-100 rag/100 g)
%
High Low
11[igh Low High Low ttigh Low High Low High Low High Low High Low High Low 20 24
20 20 GO 65 33 44 70 28 20 26 20 21 24 22 42 20 1 14
20 20 50 56 14 19 30 23 9 22 4 9 9 14 13 ]9 5 5g
100 100 83 86 42 43 43 $2 "45 85 20 43 :18 64 31 95 0.1 1.6
2.4 3.5 1"7 2.2 0'6 1.0 0-7 2.1 0.5 2"7 0.3 1.2 0.4 1-8 0.3 2.2
10 1,i
44 20
21 30 28
24 44 24 28 20 26 20
20 33 28
20
0 0
0 0 0
0 0
0 0 0 0
0 0 0 0 0 0 0 0 0
0
0 0 0 0 0 0 '0 o 0 0
0 0
Av.* opacity
0
0 0
No. of eyes of eyes 12clative No. of developing with Max, No, ~o, of humidity of eycz cataracts cataract,o, opaeit,y of eyes cataracts
Eyolkls closed
High huraidity 9 5 - %. Low humidity below 15%. Temperature 23-26°C, * The mazimum ayerago opacity for each group is the smrl of the dense~ grade of tens ol)aeiLy in each a~fima], divided hy the total number of eye~.
Rats
Hamsters
Mice
Mice
Hamsters
Mice
Mice
Hamstcrs
A,fiiaml
Deattl
:Method of eat~raet production
'eversibte tens opacities"
Eyelids open
Effect of high a. ut low hum.idity on "acute
T.u3r,~: [I
t~
....
.
.
.
-
_ _ ,
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Tempera.tu,'o
.
0-4°0
.
Random
t~ol~tive humidi~y
.
35--60°(] 23-26~C 8-t2'C
.
Low (balow 15%)
.
35-40<'C .,,-~'s~ q~oo,~ 8-12~0
::
High (95+%)
...-.
.
.
.
.
-
~
..
.
.
.
.
.
.
.
.
,
.
.
.
.
,
%
Eyelids open
.
~o,
.
•
.
.
.
.
.
.
.
.
__
_'.._
20
]2 19 -0
,i i~ 31
IO0
130 95 ~0o
6 31 91
3'3
l.f~ 2.2 3.4
0.1 0.3 3"5
24
20 44 ~0
25 20 28
of eyes of eyes Mt~x, developblg witch av. h'o, of cataracts cataracts opaeit,y eyes
.
* Par~muotc~r and ~luclear opaeitlca
26
.90 20 20
65 42 34
No, of eyes
~
.
• _ _ _
i i m | l
.
.
.
.
~o.
.
%
Eyelids etched
i
.
.
.
.
.
.
.
In
_'20
0 0 1
0 0 5
83
0 0 5
0 0 18
1-8'
0 0 0.I
0 0 0"3
of eyes of eye~ Max. developing with av. cataracts oataract~ opacity
_ _
Bffects of humidity and te.',,?crat.re on "acute reversible lens o~aci~ies in a~,e,'theti~d hamsters _
Random
(bolow15%)
Low
(95+%)
}_Iigh
P~lative humidii>y
20
22 20 22
3~-40¢C 23-26°C 8-12¢C 0-4°C
22 20 22
20
22 20 20
I0 20 22
I00
190 I00 91
46 i00 i00
4.0
3"~ 3"5 3.4
0-5 2.4 4.0
Parannele~rand nuclearopacities.
N~,of eyes
35-40~0 2336°0 8-12~0
Temperature
20
20 20 20
20 20 20
0 0 IO I00
20
0 0 IO 0 0 ~
0 0 2
3,6*
0 0 O-I
0 0 0.I
Eyelids open •ydid8 dosed No, % No. % of eyes of eyes M,~:, of eyes of ~yes ~lax. d~velopi~g with av. ~o. of developing wi~b~ a~. cataracts cataracts opacity eyes cataracts eataraeVz opacif,y
Effects of hv.m~4ity and to.~pc'rature on, "acute .reversible &:nsopacities" in deag l~a.msters
'/'asL~ IV
26
F . T. F R . A U N F E L D E R
AND
II. :P. t ~ U I t N 8
and is unaffected by daily barometric laboratory changes: Lens opacities develop equally in hamsters anesthetized or ki|led by cervical fracture when exposed to atmospheres of air, 100% 0~, I 0 0 % CO 2, 100% N~, or 90% 0 ~ - - 1 0 % COz, T A 13LF. V
Differences in "acute reversible le~s opacities" and cold eataract~ in hamsters "Acu¢~ ro~er~ibie lena opacities" Location o f cat, ar~,ct
Anterior subcapsular
"Cold" cataract Deep cortical or
nuclear Influence of ton~perature
Increases with low t e m p e r a t,m'e
l l a r e l y occurs a b o v e 5"C
Lid closure
Prevent~ opacity
N o effect
Cataract, c|eara in jnitia~ing c ~ v i r o n m e n t
Yes
No
Pressure on lens through intact, eorne~
Clears o p a c i t y ilx aFe~
No effceL
Of pr~s!ittll'O
Refractile bodies Small brownish refractile bodies wlfich a p p e a r biomicroscopically as changes in the lens c~psuIe shagreen were seen in anesthetized h a m s t e r s at 4-12¢C a n d in dead animals below 4°C. With dead h a m s t e r s k e p t at ,'oom t e m p e r a t u r e and high humidit,;,. 54°,/0 of eyes in an environment of 90~/o O o - 10~/o C0e a n d 9 % of eyes in 100% 0., showed these refraetite lens changes, which were not seen in CO., or N 2 atmospheres. The refractile bodies were more frequent in live animals and in the closed eyelid series. Histology a.~d osmolarity No histologic abnornaalJ~" was noted in cataractous lenses of eyes removed during various stages of cataract development, fixed in C~rnoy's solution or 10% form~din, and stained with periodic acid-Schiff, hemutox3rlin-eosin, or triohro me stai ns. EIectron microscopic and biochemical studies will be reported elsewlaerc. Comparison of anterior chamber aqueous osmolarity in hamsters with one eye open, the other eye closed, are shown in Table VI. I n live animals u n d e r room conditions no difference was found with 1 to 2 + lens changes. Wit.h 3 or 4 + lens changes a statisticMly significant increase in aqueous osmolari~y was found in the open c a t a r a c t o u s eye. This was especially true in eyes pre-treated with 10% phenylephrine which causes increased drying effects. I n dead animals regardless of the degree of lens chat~g~ there was an increase in aqueous osmolarity in the e.~posed eye even a t 95~o relative humidity. Comparison of normal right and left eyes showed no significant differences in aqueous osmolarity. Anoxia, asphyxia a.nd stress "~Vhen anoxia was induced in r a t s h d closure in iive auimals totally prevented lens changes (Table VII). Lens opacity developed in only one of 34 eyes in dead animals.
Normal cmltrols Rigk~ eye eompar~ lef~
/geml Cervical fracture
23-26°C 30-80%
23-26°C 95%
5
16 11 5
6
Wit,h I0% phenylephrhao eTe drops at s~ar£ of e.xperitrtci~'~
5 5 6
5
23-26°C 30-40% 6
0
369
383 455 453
620
467
372 442 467
Miiliesmoles ~
Right eye
0 1 "t2 to 3 +
4+
4+
1 ~o 2 + 3+ 4-]-
~No, Degree altinlEtls ea.tarac~
With 1% atropt~lc eye drops ~4 '~ hr earlier
A~ive Pontobarh{tal ETOH mixburc wit.hou~eye drng.~
hiebhod
Temperature and relst.ive humidi~,y
Right eye open
0
0 0 0
0
0
0 0 0
346 379 342
392
366
323 399 397
moles "~o
Miliios-
365
Left eye
c~tarae~
Degree
L~ft, eye dozeA
A,n,terior chamber aqueous osmolari y--hamsters
+4
+ 37 + 74 -I-63
+230
+101
+{-18 +47 +69
Differeaees
0-4
0.001 0.001
0.00I
0-001
0.4 O.O01 0-901
Prob. ~biLi~y
28
IV. "£. F R A U N F E L I ) l g I ~
AND
1%. 1~. : B U R N S
This possibility could h a v e been due to incomplete lid closure. Closure of the eyelids did n o t totally p r e v e n t c a t a r a c t f o r m a t i o n u n d e r asphy-xic conditions. F o u r early at.age c a t a r a c t s were fotmd in 26 eyes in the live animals, and i1 of 21 eyes in dead :I?a~5= V I I
Effect, of lid position on cr~taracts induced by anoxia amd asp/~yxia Live rats Eyelids open No. of eyes
No. of cataracts
])ead rags
Eyelids closed No, of eyes
No. of eatar,~ets
Eyelids open No. of eyes
Eyelids closed
No. of cataracts
No, of eyes
No. of cataraet.s
Anoxia
IS
9
12
0
32
27
34
1
A s p h 5 .-xir~
26
20
26
4
21
15
21
I1
animals u n d e r closed lids. The live mfimMs wh.;ch developed lens changes under closed lids were in p r e - t e n n i n a l asphyxic state. No c a t a r a c t s were found under closed Iids in a n i m a l s subjected to stress, exceptfor 1 + lens changes in 10~'o of animals k e p t ag low t e m p e r a t u r e for over -48 hr. 4. D i s c u s s i o n
The m a j o r stimulus for the " a c u t e reversible lens o p a c i t y " type changes appears to be mediated through the cornea, since lid. elosm'e, a corneal cont'~ct lens. or a.:: airt i g h t cuI) over the open eye prevents d e v e l o p m e n t of c a t a r a c t s w i t h a n y method used. Since the initial cal.aract is limited to tire pupillury area., ghi:.~ also suggests trans-corneal factors att~cthlg the a~terior c h a m b e r aqueous h u m o r and, in turn, the lens. Since ion exchange occurred only in t h e sm'face of t.he lens, equilibrium being a t t a i n e d r a p i d l y ~ i t h the suxrounding aqueous (PMm, 1948), t.he loss of lens transp a r e n c y was anterior subcapsular. E v a p o r a t i o n of w a t e r t h r o u g h the cornea, concentrating the aqueous, in turn affecting t h e lens has been suggested as the cause of d e h y d r a t i o n and a.eute pos~ m o r t e m c a t a r a c t s (Goldmamt a n d l%abinowitz, 1928). Our results eonf~rm evaporation as t h e p r l m a r y cause of m a n y of the~e c a t a r a c t s since Ligh humidi W p r e v e n t e d or m a r k e d l y irdfibited lens opacities a t room t e m p e r a t u r e Mong w i t h the increased osmolarity of t;he aqueous. However, other factors m a y be operative since high h u m i d i t y did n o t significantly p r e v e n t the lens opacities due to tevorphanol, c h l o f promazine, low t e m p e r a t u r e a n d c a t a r a c t s developh~g i m m e d i a t e l y a f t e r death, although lid closure did. Significant lens changes were found in post morcem experiments ag 90 n- )/o reb~tive h u m i d i t y a t all t e m p e r a t u r e levels where e v a p o r a t i o n shotdd not be a m a j o r factor. I n c r e a s e d aqueous osmola~ity was f o u n d in t h e open eye even if no c a t a r a c t deveIoped. ~,Vhy this should occur is unknown. A p a r t i a l explanation for lens changes in dead animals is t h e decreased metabolic r a t e secondary to 10-15°0 drop in boyd ~emperar a r e since decreasing t h e a m b i e n t t e m p e r a t u r e increases t h e incidence a n d degree of cat~rao~sregardless of h u m i d i t y i~ live or d e a d animMs (Tables I I I a n d IV). Therefore,
ACUTE I~EVEI~SIBLE LENS O P A C I T Y
29
t h e r e are intErrElationships o f v a r i o u s factors, especially tempero~ture ~nd h u m i d i t y , affecting t h e lens t r a n s p a r e n c y . Since nourislm~ent of t h e lens i.~ t o t a l l y d e p e n d e n t orl t h e aqueous, a n y m e t h o d w h i c h decreases a q u e o u s p r o d u c t i o n , e.g. general a n e s t h e s i a , cold, s y m p a t h o m i m e t i c agents, v a s o c o n s t r i c t i o n or shook, m a y p o t e n t i a t e a tra ns-coroeal ( t e h y d r a t i u g stimulus. Topical p h e n y t e p h r i n e m a r k e d l y e n h a n c e s t h e s e c a t a r a c t s a n d also causes bhc d r i e s t ,~nterior segment, shallowest, a n t e r i o r c h a m b e r s a n d t h e g r e a t e s t aqueous c o n c e n t r a t i o n . T h i s s u p p o r t s t h e i m p o r t a n c e ok" a q u e o u s h u m o r p r o d u c t i o n in this t y p e of lens opacit.y (~Vcins~ock a n d S t e w a r t , 1961:,. I n v i c e cold cataract, s a p p e a r to be o£ t w o typed, Vhe " a c u t e reversible lens o p a e i t y " a n d t h e p a r a n u c t c a r a n d nuclEa~ " c o l d " c a t a r a c t : ~ l t h o u g h t h e effect of lid position ou " e o ( d " c a t a r a c t s h a d r e c e n t l y been recognizcd. (Klass a n d B u r n s , 1964), CItE diffe, rchrist, ion of two d i s t i n c t t y p e s was n o t noted. The t r u e cold c a t a r a c t m a y bc due to p r e c i p i t a t i o n of g ~ m m a c r y s t a l l i n (Zigntan a n d L e r m a u , 1965). P r e s e n t d a t a indicates anoxia, c a t a r a c t s fit in t h e " a c u t e reversible lens o p a c i t y " classification, while results w i t h a s p h y x i a are less clear cut. Stress generate(1 c a t a r a c t s also can be p l a c e d in the s a m e group, except ia t h e long t e r m h y p o t h e r m i a e x p e r i m e n t s . Brownish, refractile bodies o£ t h e lens h a v e been n o t e d also by T r o v e r - R o p e r , who fcl~ these were p i g m e n t g r a n u l e s ( T r o v e r - R o p e r , 1957), b u t tl~eir t r a n s i e n t n a t u r e a n d t h e i r biomic~-oscopie appe~rances m a k e tlxis seem u n l i k e l y . T r a n s i e n t lens c h a n g e s have r e c e n t l y been described in p r e m a t u r e irffants ( M c C o r m ick 1968). These are posterior s u b c a p s u l a r a n d p e r s i s t from 10 to 1S d a y s a n d seem to h a v e n o correlatio~t to the ions cha~ges described herE. G o l d m a n n , who first described ~he effect of lid positio~ on curt, s i n lens changes, st,~tccl, " I f incorrect decisions in cataract, research are avoided, t~he purpose of this p a p e r is s e r v e d " . This s t a t e m e n t is as true t o d a y as it was w h e n m a d e a h n o s t o n e - h a t / c e n t u r y ago, ACI(NO~V L1£ D G ~ I E N T S The assistance of Mrs L. Willenberg and Miss R,. Warren a n d the advice from Dr Calvin H a n n a is gratefully acknowledged. This work was supported in part by U.S. Public H e a l t h Training G r a n t NB-5042-10, NB-10041-432 ant] Service G r a n t NB0-4770-03 from the National I n s t i t u t e of Neurological Diseases and Blindness, U.S. Public tIea lth Service. REFERENCES
Amante~,, G. (1934:). Atti Accad. Naz. ~ : ~ e l Rer~l. Clause ,~c.i. Fis. :][at. Nat. 20, 220. Bellows, J. and Nelson, ]D. (1944). Arch. Ophthalmol. (Chicago) 31,250. Biozzi, (3. (1935). Arch. Ophthab~ol. (Berlin) 133, 423. Caceia, A. IL., Debarnot,, )~. 0., hhmilla, L. G. and Russi, I. T. (1959). Semana '.lied. (Buenos Aires) 115, 751. Fraunfeider, F. T. and Burns, R. P. (1962). Prec. See. Eccp. Biol. ~fed. 110, 72. Fratmfelder, F. T. and ]3ttr~s, R. P. (1966). Arch. Ophlhatnwl. (Ohicago) 76, 599. Goldmann, H. and I~abino~,qtz, G. (1928). Kl.in. 2tgonat~bl. Auqenheitk. 81,771. Klass, A. 5[. and Burns, ~. ~.. (1964). Exptl Eye Jr~e~. 3, 213. ~IeCorraiok, A. Q. (1968). Can. d. Ophthal.mol, 3, 202. ~[orone, G. ~nd Citron.i, ~I. (k950)..Riv. ,lIexl. Aeror~, Spaz. 13, 655. Palm, E. (1948). Acts O?7~thatmol. 26 (Suppl. 32), t, 8elye, H. (1937). Endoc, rino~ogy 219 169. Smith, A. A., Gayltt, ft. and K~plan, !~[. (1963). Retort Advart. Biol. Psychiat. 6~ 208. Smith A. A., Ggvitt, g. and Karmin, ,~. (1966). Arch. Ophthalmol. (Ohicaffo) 75;~ 99.
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F. T. F R A U N F E L D E R 2~ND R. P. BURNS
Trevor-Roper, P', D. (1957). Tra~.~. Ophthal.mol. ,~oc. U.K. 77, 401. Turn Suden, C. and Wyl.nau, L. C. (1940). Endocri~mlogy 17, 628. Weinstock, M., Stewart, H. C. and Butterworth, K. 1%. (1958). Nalure 182, 1519. Weinstock, M. and Stewart, H. C. (1961). Brit. J. Optt~kalmoI. 45~ 408. Zigmc~n, S. and Lerman, S. (1965). Ea':ptl ,Eye Res. 4~ 24.