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Light Transmission by Colored Spectacle Lenses in the Visible Spectrum
LIGHT TRANSMISSION areas. Microscopic section shows tumor to consist of myomatous tissue, and connective tissue which in some areas shows cartilaginous metaplasia. These connective tissue structures sur round glandular structures. Some of the glands show simple cuboidal epi
973
thelial hyperplasia. No mitotic nuclei are evident. In some areas there is lymphatic infiltration. Diagnosis—mixed tumor of lacrymal gland (teratoma). 121 East Sixtieth street
LIGHT TRANSMISSION BY COLORED SPECTACLE LENSES IN T H E VISIBLE SPECTRUM LAURANCE D. REDWAY, NEW YORK
M.D.
Tables are provided by means of which the relative value of different kinds of tinted spectacle lens and of gelatin ray filter, as applied to various purposes, may be estimated. but will reduce the resolution in dis tant vision because of their property of increasing the atmospheric haze ef fect. At ten thousand feet (Mount Wilson) the haze effect at a wave length of 413 mm. was found to be 0.042; at 503 mm. to be 0.019; at 575 mm. to be 0.016.1 Lenses transmitting a great deal of light in the green band are very well tolerated. Because of the increased brilliancy of objects seen through such a lens, and because the definition ob tained is good without marked increase in contrast values, these lenses are comfortable. In using these, it will be valuable to recall the Purkinje effect, namely that in light of great intensity the sensitivity of the eye is greatest in the green band (590 mm.), and that therefore lenses of greater density may be prescribed in this band without re With these data available, it should ducing too greatly the brilliance of be quite easy for any oculist to pre green-reflecting objects. scribe a lens with definite knowledge Lenses transmitting high values in of how much light and of what qual the orange or red may be useful where ity it will transmit. To this end the it is desired to obtain very detailed spectrum has been divided roughly distant vision and exaggerated con into three parts, blue, green, and red. trast, while if simply reduction of at In general, lenses transmitting high mospheric haze is desired a lens trans values in the blue band will tend to in mitting the highest values in the yel crease the resolving power of the eye low band should be used. In this con for close work provided the total illunection it should be pointed out that W.L.* there is a vast difference between mination is adequate ( R = ■), orthochromatism and isochromatism. 2. N.A. * That is, where R=resolving power, W.L.=: The requisite in the latter case is wave length, and N.A.=the numerical aperture. merely that all colors shall be trans-
Information as to the transmission of light by colored spectacle lenses of various makes of optical glass is not available to the oculist or to the opti cian in readily understandable form. Under certain circumstances it would be desirable to know the behavior of various spectacle lenses with respect to the composition and amounts of light which they transmit. Many ocu lists do not know a number of these which are on the market nor their trade names, much less their physical characteristics. But there is a definite and growing use for such lenses, not alone in the field of sports but also in industry. Therefore a series of deter minations have been made in order to ascertain the characteristics of a num ber of such lenses currently on the market, utilizing blanks as furnished by the manufacturers of a standard thickness of two millimeters.
974
LAURANCE D. REDWAY
mitted without respect to their rela tive natural luminosities, while the former requires all colors to appear in the order of their natural brightness. A lens which will satisfy the require ments of orthochromatism will be found to have a nearly equal trans mission in all the color bands. Its density to white light may be small or great as long as the former condition is fulfilled. Too little attention has been paid to the function of the colored spectacle lens as a color filter, though many of them are admirably adapted to this purpose. Table 1 was compiled from tests of the various lenses made with a photo meter of the Martens type and using a i.
standard source of illumination opera ted at the same degree of intensity throughout. Transmission was read direct as follows: T = cot2 (greater angle) X tan 2 (lesser angle), the lo garithms of these angular values be ing used and the numerical equiva lents read to three significant figures. The transmissions are plotted against the mean wavelength values of Wratten filters nos. 47, 58, and 29. From these values of T, the absorption and density values may be calculated if desired as follows: 1. Absorption = 1 — T , and 1 = 2. Density log———
TRANSMISSION OF LIGHT OF DIFFERENT WAVELENGTH IN THE VISIBLE SPECTRUM BY SPECTACLE LENSES OF COLORED GLASS
Transmission No. i 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
Lens Spectacle Softlite Amethyst Plate glass Crookes Blue Amethyst Softlite Noviol Hallauer Noviol Amber Softlite Fieuzal Smoke Amethyst Amber Uviol Amethyst Blue Crookes Fieuzal Amber Fieuzal Smoke Amber Crookes Hallauer Smoke Blue Amber Blue
Color White Lightshade Number 1 White Number I "A" Number 2 Darkshade "B" Number 62 "C" Number 1 Sportshade "A" "A" Number 3 Number 2 Yellow Number 4 "B" Number 2 "B" Number 3 "C" "B" Number 4 Number 3 Number 63 "C" "C" Number 5 "D"
Blue has a Green has Red has a White has
value approximately a value approximately value approximately a value approximately
Blue 93-50 9350 85.00 86.50 93" 99.54 76.00 89.00 9.78 10.56 H-35 69.00 66.00 59-57 7000 65.00 59-10 28.71 60.20 75-69 75-34 55-59 4050 4046 52.00 18.00 55-85 15-70 34-00 55-50 11.50 40-94
in per cent
Green 94.00 81.00 87.00 87.00 80.54 81.10 80.00 75-50 7200 87.50 9000 82.00 72.50 80.13 69.70 69.75 65.20 64.57 60.80 69.67 74-82 69.67 54-20 64.72 5T-50 47-io 47-65 37-50 34-00 3150 21.20 19-68
Red 87.00 87.00 79-10 94-00 9600 86.50 92.50 86.90 90.00 66.00 85.00 80.50 75-50 80.36 73-10 6910 70.50 86.30 75-30 60.40 80.73 74-99 69.20 55-59 55-00 4400 55-85 40.28 37-20 21.73 29.80 12.39 4i500 5.500 6,500 5>8oo
White 93.72 93.62 86.99 86.78 86.30 86.25 82.91 81.16 81.00 80.78 76.00 75.20 75-15 73-29 70.28 69.90 69.80 69.67 65.30 65.17 6502 65.02 61.60 59-8| 52.06 51-53 50-59 40.37 34-II 28.58 24.10 15.82
975
LIGHT TRANSMISSION By reading the column headed "white", the total transmission of white light (tungsten filament) may be obtained, the samples being so ar ranged that they appear in the order in which they transmit white light. By reading the columns from right to left, the transmissions at the other bands may be had. This arrangement permits a lens to be found immedia tely on the basis of the whole amount of light it transmits, and its differen tial transmission to be later read. No attempt has been made to ob tain a greater accuracy than ten per cent, since the color bands are broad. The object has been to present a practically graded table of the char acteristics of the lenses tested for the use of oculists and opticians who might wish to take advantage of these. Since some lens must be worn to correct errors of refraction, it seems only common sense that that lens shall be utilized which most closely approximates the require ments of the individual case. Modern industry is making such demands and is requiring such a high degree of visual acuity and sustained visual ef
fort that any aid or assistance which can be afforded the human eye, in the performance of work it was not pri marily designed to do, is not to be overlooked. Micromeasurements are be coming every day more common, greater and greater accuracy is being required of the human eye. This is putting the responsibility squarely up on the oculist to obtain for those who consult him not alone a correct re fraction, but also the highest possible visual acuity and efficiency. The use of color filters to promote this has not been carried to its logical limit, nor will it be until there is a more general understanding by oculists of the avail ability of this form of compound cor rection. The irritating quality of light in the ultraviolet has been stressed and overstressed, but very little has been said of the physical characteristics of the rays of the visible spectrum and how these might be adapted to practi cal uses. Those familiar with the practices of modern photography have long used light filters for the produc tion of well recognized effects on pho tographic emulsions, but the use of such filters or modified forms of them
TRANSMISSION OF LIGHT OF DIFFERENT WAVELENGTH I N T H E VISIBLE SPECTRUM BY GELATINE L I G H T FILTERS ( W R A T T E N ) . 2
No.
Filter Blue
Transmission, in per cent Green Red Yellow 81.10 78.30 82.20 66.50 74.00 00.00 26.20 5.00 1.10 64.50 1.78 00.00
White
79-90 78.30 82.90 76.10 7940 4.60 9.10 00.00 00.00 43.20 00.00 00.00
86.00 80.00 5800 33-00 42.00 1.30 38.00 38.00 12.50 70.00 25.00 00.00
00.00
00.60
00.00 1.14 2.68 00.00
74-50 650 m m . 9.20 00.37 00.00 00.00
00.00 00.00
00.00 00.00
12
No. 4 No. 9 No. 21 No. 23 No. 30 No. 34 No. 38 No. 40 No. 43 No. 51 No. 60 No. 88 Infrared
00.00 00.00 00.00 00.00 38.10 39-70 70.80 00.00 61.40 37.00 00.26 00.00
13
No. 70
[ONOCHRO]MATIC F I L T E R S 00.00 00.00
14 15 16 17
No. No. No. No.
71 72 73 74
00.00 00.00 00.00 00.00
18 19
No. 75 No. 76
00.00 9.50
I 2
3 4 5 6 7 8 9
10 II
81.10 78.30 2510 00.00 00.00 00.00 49.00 50.60 15.00 74-50 38.10 00.00.
00.00 00.00 00.00 4.00 500 m m . 14.10 00.00
1.00 1.00 3-30 3-30 1.50 0.10
976
M. URIBE TRONCOSO
in combination with correcting lenses has not yet been intelligently devel oped. While the coloration of optical glass is practically limited by the conditions of manufacture, it is practical to use ordinary gelatine filter material placed between thin wafers of glass and mounted in a fitover frame, thus af fording a great variety of filter effects not at present obtainable otherwise. Monochromatic light may thus be uti lized or any desired band at will with great ease. A field for such filters has recently developed with the popularity of the infrared as a therapeutic mo dality. None of the sources of infrared as found currently on the market are satisfactory, in that they are far from being monochromatic, some of them
emitting light as far down as the bluegreen. But by using gelatine filter Wratten no. 88 suitably mounted, it is possible to employ almost pure in frared emanations from sunlight or other sources for treatment purposes, and to be sure of the exact composi tion of the light used. (Table 2.) With the information afforded by these tables it should be possible to control with some exactness the pre scription of colored glass lenses, and to have at hand for further experi mental work data as to the character istics of some of the commoner gela tine filters which may be used as adjuncts. The Andrew Todd McClintock Me morial Foundation, 285 Madison avenue
References 1. Aerial haze, monograph no. 4. Eastman Kodak Co., 1923, p. 77. 2. Wratten light filters. Eastman Kodak Co., 1925.
THEORIES OF ACCOMMODATION M. URIBE TRONCOSO,
M.D-
NEW YORK CITY
Recent investigations bearing upon the two principal theories as to the mechanism of accommodation, namely those of Helmholtz and Tscherning, are summarized and dis cussed.
The mechanism of accommodation has been so much discussed, and such different and contradictory theories have been maintained upon the subject, that new facts are always welcome, particularly in regard to the condition of the zonule. The old controversy be tween the two principal theories— namely, that of Helmholtz as to relaxa tion of the zonule and lens capsule dur ing accommodation and that of Tscherning and others, which considers tightening of the zonular fibers and compression of the lens as the principal factors in accommodation—is still open. The biomicroscope (slit-lamp) has proved of considerable value for the study in vivo of the condition of the
zonule and lens when these structures become visible in cases of congenital or operative colobomas, irideremia, ectopia lentis, and so on. The appearance and structure of the zonule and lens margin have been carefully studied with the biomicroscope, both in enu cleated normal eyes and in patients in whom these parts were exposed to view. The findings of Meesmann, Treigny and Bernard, and Mawas con firmed the histological descriptions of the zonular fibers and their mode of attachment to the periphery of the lens on its anterior and posterior surfaces. T o direct and indirect illumination the fibers appear as straight, brilliant, golden filaments arranged in groups, each of which corresponds to the head
973
thelial hyperplasia. No mitotic nuclei are evident. In some areas there is lymphatic infiltration. Diagnosis—mixed tumor of lacrymal gland (teratoma). 121 East Sixtieth street
LIGHT TRANSMISSION BY COLORED SPECTACLE LENSES IN T H E VISIBLE SPECTRUM LAURANCE D. REDWAY, NEW YORK
M.D.
Tables are provided by means of which the relative value of different kinds of tinted spectacle lens and of gelatin ray filter, as applied to various purposes, may be estimated. but will reduce the resolution in dis tant vision because of their property of increasing the atmospheric haze ef fect. At ten thousand feet (Mount Wilson) the haze effect at a wave length of 413 mm. was found to be 0.042; at 503 mm. to be 0.019; at 575 mm. to be 0.016.1 Lenses transmitting a great deal of light in the green band are very well tolerated. Because of the increased brilliancy of objects seen through such a lens, and because the definition ob tained is good without marked increase in contrast values, these lenses are comfortable. In using these, it will be valuable to recall the Purkinje effect, namely that in light of great intensity the sensitivity of the eye is greatest in the green band (590 mm.), and that therefore lenses of greater density may be prescribed in this band without re With these data available, it should ducing too greatly the brilliance of be quite easy for any oculist to pre green-reflecting objects. scribe a lens with definite knowledge Lenses transmitting high values in of how much light and of what qual the orange or red may be useful where ity it will transmit. To this end the it is desired to obtain very detailed spectrum has been divided roughly distant vision and exaggerated con into three parts, blue, green, and red. trast, while if simply reduction of at In general, lenses transmitting high mospheric haze is desired a lens trans values in the blue band will tend to in mitting the highest values in the yel crease the resolving power of the eye low band should be used. In this con for close work provided the total illunection it should be pointed out that W.L.* there is a vast difference between mination is adequate ( R = ■), orthochromatism and isochromatism. 2. N.A. * That is, where R=resolving power, W.L.=: The requisite in the latter case is wave length, and N.A.=the numerical aperture. merely that all colors shall be trans-
Information as to the transmission of light by colored spectacle lenses of various makes of optical glass is not available to the oculist or to the opti cian in readily understandable form. Under certain circumstances it would be desirable to know the behavior of various spectacle lenses with respect to the composition and amounts of light which they transmit. Many ocu lists do not know a number of these which are on the market nor their trade names, much less their physical characteristics. But there is a definite and growing use for such lenses, not alone in the field of sports but also in industry. Therefore a series of deter minations have been made in order to ascertain the characteristics of a num ber of such lenses currently on the market, utilizing blanks as furnished by the manufacturers of a standard thickness of two millimeters.
974
LAURANCE D. REDWAY
mitted without respect to their rela tive natural luminosities, while the former requires all colors to appear in the order of their natural brightness. A lens which will satisfy the require ments of orthochromatism will be found to have a nearly equal trans mission in all the color bands. Its density to white light may be small or great as long as the former condition is fulfilled. Too little attention has been paid to the function of the colored spectacle lens as a color filter, though many of them are admirably adapted to this purpose. Table 1 was compiled from tests of the various lenses made with a photo meter of the Martens type and using a i.
standard source of illumination opera ted at the same degree of intensity throughout. Transmission was read direct as follows: T = cot2 (greater angle) X tan 2 (lesser angle), the lo garithms of these angular values be ing used and the numerical equiva lents read to three significant figures. The transmissions are plotted against the mean wavelength values of Wratten filters nos. 47, 58, and 29. From these values of T, the absorption and density values may be calculated if desired as follows: 1. Absorption = 1 — T , and 1 = 2. Density log———
TRANSMISSION OF LIGHT OF DIFFERENT WAVELENGTH IN THE VISIBLE SPECTRUM BY SPECTACLE LENSES OF COLORED GLASS
Transmission No. i 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
Lens Spectacle Softlite Amethyst Plate glass Crookes Blue Amethyst Softlite Noviol Hallauer Noviol Amber Softlite Fieuzal Smoke Amethyst Amber Uviol Amethyst Blue Crookes Fieuzal Amber Fieuzal Smoke Amber Crookes Hallauer Smoke Blue Amber Blue
Color White Lightshade Number 1 White Number I "A" Number 2 Darkshade "B" Number 62 "C" Number 1 Sportshade "A" "A" Number 3 Number 2 Yellow Number 4 "B" Number 2 "B" Number 3 "C" "B" Number 4 Number 3 Number 63 "C" "C" Number 5 "D"
Blue has a Green has Red has a White has
value approximately a value approximately value approximately a value approximately
Blue 93-50 9350 85.00 86.50 93" 99.54 76.00 89.00 9.78 10.56 H-35 69.00 66.00 59-57 7000 65.00 59-10 28.71 60.20 75-69 75-34 55-59 4050 4046 52.00 18.00 55-85 15-70 34-00 55-50 11.50 40-94
in per cent
Green 94.00 81.00 87.00 87.00 80.54 81.10 80.00 75-50 7200 87.50 9000 82.00 72.50 80.13 69.70 69.75 65.20 64.57 60.80 69.67 74-82 69.67 54-20 64.72 5T-50 47-io 47-65 37-50 34-00 3150 21.20 19-68
Red 87.00 87.00 79-10 94-00 9600 86.50 92.50 86.90 90.00 66.00 85.00 80.50 75-50 80.36 73-10 6910 70.50 86.30 75-30 60.40 80.73 74-99 69.20 55-59 55-00 4400 55-85 40.28 37-20 21.73 29.80 12.39 4i500 5.500 6,500 5>8oo
White 93.72 93.62 86.99 86.78 86.30 86.25 82.91 81.16 81.00 80.78 76.00 75.20 75-15 73-29 70.28 69.90 69.80 69.67 65.30 65.17 6502 65.02 61.60 59-8| 52.06 51-53 50-59 40.37 34-II 28.58 24.10 15.82
975
LIGHT TRANSMISSION By reading the column headed "white", the total transmission of white light (tungsten filament) may be obtained, the samples being so ar ranged that they appear in the order in which they transmit white light. By reading the columns from right to left, the transmissions at the other bands may be had. This arrangement permits a lens to be found immedia tely on the basis of the whole amount of light it transmits, and its differen tial transmission to be later read. No attempt has been made to ob tain a greater accuracy than ten per cent, since the color bands are broad. The object has been to present a practically graded table of the char acteristics of the lenses tested for the use of oculists and opticians who might wish to take advantage of these. Since some lens must be worn to correct errors of refraction, it seems only common sense that that lens shall be utilized which most closely approximates the require ments of the individual case. Modern industry is making such demands and is requiring such a high degree of visual acuity and sustained visual ef
fort that any aid or assistance which can be afforded the human eye, in the performance of work it was not pri marily designed to do, is not to be overlooked. Micromeasurements are be coming every day more common, greater and greater accuracy is being required of the human eye. This is putting the responsibility squarely up on the oculist to obtain for those who consult him not alone a correct re fraction, but also the highest possible visual acuity and efficiency. The use of color filters to promote this has not been carried to its logical limit, nor will it be until there is a more general understanding by oculists of the avail ability of this form of compound cor rection. The irritating quality of light in the ultraviolet has been stressed and overstressed, but very little has been said of the physical characteristics of the rays of the visible spectrum and how these might be adapted to practi cal uses. Those familiar with the practices of modern photography have long used light filters for the produc tion of well recognized effects on pho tographic emulsions, but the use of such filters or modified forms of them
TRANSMISSION OF LIGHT OF DIFFERENT WAVELENGTH I N T H E VISIBLE SPECTRUM BY GELATINE L I G H T FILTERS ( W R A T T E N ) . 2
No.
Filter Blue
Transmission, in per cent Green Red Yellow 81.10 78.30 82.20 66.50 74.00 00.00 26.20 5.00 1.10 64.50 1.78 00.00
White
79-90 78.30 82.90 76.10 7940 4.60 9.10 00.00 00.00 43.20 00.00 00.00
86.00 80.00 5800 33-00 42.00 1.30 38.00 38.00 12.50 70.00 25.00 00.00
00.00
00.60
00.00 1.14 2.68 00.00
74-50 650 m m . 9.20 00.37 00.00 00.00
00.00 00.00
00.00 00.00
12
No. 4 No. 9 No. 21 No. 23 No. 30 No. 34 No. 38 No. 40 No. 43 No. 51 No. 60 No. 88 Infrared
00.00 00.00 00.00 00.00 38.10 39-70 70.80 00.00 61.40 37.00 00.26 00.00
13
No. 70
[ONOCHRO]MATIC F I L T E R S 00.00 00.00
14 15 16 17
No. No. No. No.
71 72 73 74
00.00 00.00 00.00 00.00
18 19
No. 75 No. 76
00.00 9.50
I 2
3 4 5 6 7 8 9
10 II
81.10 78.30 2510 00.00 00.00 00.00 49.00 50.60 15.00 74-50 38.10 00.00.
00.00 00.00 00.00 4.00 500 m m . 14.10 00.00
1.00 1.00 3-30 3-30 1.50 0.10
976
M. URIBE TRONCOSO
in combination with correcting lenses has not yet been intelligently devel oped. While the coloration of optical glass is practically limited by the conditions of manufacture, it is practical to use ordinary gelatine filter material placed between thin wafers of glass and mounted in a fitover frame, thus af fording a great variety of filter effects not at present obtainable otherwise. Monochromatic light may thus be uti lized or any desired band at will with great ease. A field for such filters has recently developed with the popularity of the infrared as a therapeutic mo dality. None of the sources of infrared as found currently on the market are satisfactory, in that they are far from being monochromatic, some of them
emitting light as far down as the bluegreen. But by using gelatine filter Wratten no. 88 suitably mounted, it is possible to employ almost pure in frared emanations from sunlight or other sources for treatment purposes, and to be sure of the exact composi tion of the light used. (Table 2.) With the information afforded by these tables it should be possible to control with some exactness the pre scription of colored glass lenses, and to have at hand for further experi mental work data as to the character istics of some of the commoner gela tine filters which may be used as adjuncts. The Andrew Todd McClintock Me morial Foundation, 285 Madison avenue
References 1. Aerial haze, monograph no. 4. Eastman Kodak Co., 1923, p. 77. 2. Wratten light filters. Eastman Kodak Co., 1925.
THEORIES OF ACCOMMODATION M. URIBE TRONCOSO,
M.D-
NEW YORK CITY
Recent investigations bearing upon the two principal theories as to the mechanism of accommodation, namely those of Helmholtz and Tscherning, are summarized and dis cussed.
The mechanism of accommodation has been so much discussed, and such different and contradictory theories have been maintained upon the subject, that new facts are always welcome, particularly in regard to the condition of the zonule. The old controversy be tween the two principal theories— namely, that of Helmholtz as to relaxa tion of the zonule and lens capsule dur ing accommodation and that of Tscherning and others, which considers tightening of the zonular fibers and compression of the lens as the principal factors in accommodation—is still open. The biomicroscope (slit-lamp) has proved of considerable value for the study in vivo of the condition of the
zonule and lens when these structures become visible in cases of congenital or operative colobomas, irideremia, ectopia lentis, and so on. The appearance and structure of the zonule and lens margin have been carefully studied with the biomicroscope, both in enu cleated normal eyes and in patients in whom these parts were exposed to view. The findings of Meesmann, Treigny and Bernard, and Mawas con firmed the histological descriptions of the zonular fibers and their mode of attachment to the periphery of the lens on its anterior and posterior surfaces. T o direct and indirect illumination the fibers appear as straight, brilliant, golden filaments arranged in groups, each of which corresponds to the head