- Email: [email protected]
Flexible Iris Retractor
776
June, 1991
AMERICAN JOURNAL OF OPHTHALMOLOGY
a s s o c i a t e d s t r u c t u r e . If u n t r e a t e d , t h e c o n d i t i o n h e a l s , p e r s i s t s as a s u b l u x a t i o n , or p r o g r e s s e s to a frank d i s l o c a t i o n . G e n e t i c , e t h n i c , a n d u t e r i n e factors play a r o l e in its p a t h o g e n e s i s . C o n g e n i tal h i p d y s p l a s i a o c c u r s o n c e in e v e r y 1 1 0 births, with a female sex predilection of ap p r o x i m a t e l y 5 to 1. A family h i s t o r y of t h e c o n d i t i o n is n o t e d in 1 2 % to 3 3 % o f p a t i e n t s . ' Two s i s t e r s , a g e d 9 a n d 1 2 y e a r s , w e r e e x a m i n e d b y o n e of us ( P . N . ) for b l u r r e d v i s i o n a n d photophobia. They were the only children of healthy, consanguineous parents whose moth ers w e r e s i s t e r s . B o t h girls w e r e d e l i v e r e d v a g i n a l l y at t e r m a n d h a d A p g a r s c o r e s o f 9 / 9 . B o t h girls h a d b i l a t e r a l c o n g e n i t a l h i p d y s p l a s i a , r e l a t e d to an acetabular dysplasia, diagnosed by ultrasono g r a p h y at a g e 6 m o n t h s in the o l d e r s i s t e r a n d at a g e 3 m o n t h s in t h e y o u n g e r s i s t e r . T h e r e w a s n o family h i s t o r y of hip d y s p l a s i a . The younger sister had best-corrected visual a c u i t y o f 2 0 / 2 0 in e a c h eye w i t h r e f r a c t i o n o f R . E . : -1-1.00 -1-1.25 X 3 0 a n d L . E . : - 1 . 0 0 - 1 . 2 5 X 1 5 . T h e o l d e r sister h a d b e s t - c o r r e c t e d v i s u a l acuity of R.E.: 2 0 / 4 0 and L.E.: 2 0 / 3 0 with refraction of R.E.: - 2 . 0 0 - 3 . 2 5 x 4 0 and L.E.: — 1.75 - 2 . 7 5 X 3 5 . K e r a t o m e t r i c r e a d i n g s d i s c l o s e d d i s t o r t e d m i r e s in e a c h girl. B i o m i c r o scopic examination disclosed a cone-shaped e c t a s i a o f t h e c o r n e a in e a c h girl. V o g t ' s s t r i a e w e r e n o t e d in the d e e p s t r o m a a n d D e s c e m e t ' s m e m b r a n e of the o l d e r girl. T h e e n d o t h e l i a l c e l l c o u n t was w i t h i n n o r m a l l i m i t s ( 2 , 8 9 0 ± 1 2 1 c e l l s / m m ^ in the y o u n g e r s i s t e r a n d 2 , 9 1 4 ± 3 2 1 c e l l s / m m ^ in t h e o l d e r sister).^ T h e a p p e a r a n c e of t h e c o r n e a s was c o n s i s t e n t w i t h b i l a t e r al k e r a t o c o n u s . N o e v i d e n c e o f o t h e r c o r n e a l dystrophies was noted. The ophthalmic history was u n r e m a r k a b l e for a t o p i c d i s e a s e s , o c u l a r t r a u m a , eye r u b b i n g , or h a r d c o n t a c t l e n s u s e . K e r a t o c o n u s u s u a l l y b e c o m e s m a n i f e s t dur ing a d o l e s c e n c e . M o s t c a s e s o f k e r a t o c o n u s are s p o r a d i c , b u t it is s o m e t i m e s f a m i l i a l . K e n n e d y , Bourne, and D y e r ' described keratoconus oc curring in l e s s t h a n 6 % o f t h e b l o o d r e l a t i v e s o f an affected p r o b a n d . G r e e n f i e l d a n d a s s o c i a t e s * r e p o r t e d a f a m i l i a l o c c u r r e n c e of k e r a t o c o n u s and osteogenesis imperfecta and hypothesized an a u t o s o m a l r e c e s s i v e p a t t e r n o f i n h e r i t a n c e . S e v e r a l s y s t e m i c t i s s u e d i s o r d e r s are r e p o r t e d in a s s o c i a t i o n w i t h k e r a t o c o n u s , i n c l u d i n g M a r fan's syndrome and Ehlers-Danlos s y n d r o m e . ' R e p o r t s of c o n s a n g u i n i t y h a v e b e e n c i t e d as evidence of a recessive mode of inheritance. Wynne-Davies" suggested a multiple gene he r e d i t y defect in c o n g e n i t a l h i p d y s p l a s i a w i t h acetabular dysplasia, especially when environ m e n t a l factors h a d n o t played a r o l e .
T h e i n c i d e n c e of k e r a t o c o n u s r a n g e s from 5 0 to 2 0 0 p e r 1 0 0 , 0 0 0 live b i r t h s , w h e r e a s c o n g e n ital h i p d y s p l a s i a o c c u r s o n c e in 1 1 0 live b i r t h s . Therefore, congenital hip dysplasia and kerato c o n u s is an a s s o c i a t i o n o f two i n d e p e n d e n t e v e n t s w h o s e i n c i d e n c e r a n g e s from 4 to 1 8 p e r 1 , 0 0 0 , 0 0 0 live b i r t h s . M a t h e m a t i c a l l y , t h e p r o b a b i l i t y t h a t t h i s a s s o c i a t i o n o c c u r s t w i c e by c h a n c e is e x t r e m e l y l o w . T h e e a r l y d e v e l o p m e n t of k e r a t o c o n u s a n d t h e c o n s a n g u i n i t y o f t h e p a r e n t s s u p p o r t t h e h y p o t h e s i s t h a t this is m o s t l i k e l y an a u t o s o m a l r e c e s s i v e a s s o c i a t i o n .
References 1. Coleman, S. S.: Diagnosis of congenital dyspla sia of the hip in the newborn infant. Clin. Orthop. 247:3, 1989. 2. Nucci, P., Brancato, R., Mets, Μ. Β., and Shevell, S. Κ.: Normal endothelial cell density range in childhood. Arch. Ophthalmol. 108:247, 1990. 3. Kennedy, R. H., Bourne, W. M., and Dyer, J. Α.: A 48-year clinical and epidemiologic study of kerato conus. Am. J. Ophthalmol. 101:267, 1986. 4. Greenfield, G., Romano, Α., Stein, R., and Goodman, R. M.: Blue sclera and keratoconus. Key features of a distinct heritable disorder of connective tissue. Clin. Genet. 4:8, 1 9 7 3 . 5. Wynne-Davies, R.: Acetabular dysplasia and fa milial joint laxity. Two etiological factors in congeni tal dislocation of the hip. A review of 589 patients and their families. J. Bone Joint Surg. [Br.J 52:704, 1970.
Flexible Iris R e t r a c t o r Eugene de Juan, Jr., M.D., and Dyson Hickingbotham Department of Ophthalmology, Duke University Eye Center. Duke University will receive royalties based on the sale of the iris retractors; however, the authors will receive no direct compensation. Inquiries to Eugene de Juan, Jr., M.D., Dulce Eye Center, Box 3802, Durham, NC 27710.
University
I n a d e q u a t e p u p i l l a r y d i l a t i o n can o c c u r dur ing o c u l a r s u r g e r y or a s a r e s u l t o f s c a r r i n g n e a r t h e p u p i l l a r y m a r g i n from m a n y c a u s e s . A vari ety o f m e t h o d s h a v e b e e n d e v e l o p e d t o c o r r e c t this p r o b l e m , i n c l u d i n g iris s p h i n c t e r o t o m y , s e v e r a l s u t u r e t e c h n i q u e s , " m e t a l iris r e t r a c tors p l a c e d e i t h e r t h r o u g h t h e p a r s p l a n a or t h e c o r n e o s c l e r a l limbus,'''^ a n d pharmacologic m e t h o d s . N o n e o f t h e s e m e t h o d s , h o w e v e r , are sufficiently d e l i c a t e for u s e in t h e p h a k i c e y e w h e n t h e l e n s is to b e r e t a i n e d . T h e i n f l e x i b l e
Vol. I l l , No. 6
777
Letters to the Journal
Flexible Iris Retractors
Fig. 1 (de Juan and Hickingbotham). Scanning electron micrograph of flexible iris retractor showing Silastic sleeve and hook. m e t a l iris r e t r a c t o r c a n d a m a g e t h e a n t e r i o r l e n s capsule, particularly when manipulation o f the globe causes the end of the retractor to push a g a i n s t t h e d e l i c a t e i n t r a o c u l a r t i s s u e s . To o v e r come these limitations, we developed and test ed a n e w iris r e t r a c t o r w i t h a flexible n y l o n h o o k a n d a S i l a s t i c s l e e v e . T h e r e t r a c t o r is 6 . 0 m m in l e n g t h a n d h a s a 1 . 0 - m m h o o k at t h e e n d . T h e s m a l l S i l a s t i c disk h o l d s t h e r e t r a c t o r in place (Fig. 1 ) . S i n c e b o t h t h e tip a n d t h e shaft of t h e r e t r a c tor are flexible, d a m a g e to o c u l a r s t r u c t u r e s is m i n i m a l , p a r t i c u l a r l y to t h e a n t e r i o r c a p s u l e i n p h a k i c e y e s . P l a c e m e n t o f t h e r e t r a c t o r is facili tated b y a s p e c i a l l y d e v e l o p e d 0 . 5 - m m s p a t u l a shaped knife, which makes a self-sealing limbal i n c i s i o n . T h e flexible iris r e t r a c t o r s a r e c o m p a t i ble with sutured-on contact lens rings used d u r i n g v i t r e o u s s u r g e r y a n d c a n b e c u t t o any l e n g t h to avoid i n t e r f e r e n c e w i t h a n t e r i o r s e g ment manipulations (Fig. 2 ) . T h e flexible iris r e t r a c t o r is p l a c e d a n d h e l d b y a s m a l l n e e d l e h o l d e r for s e c u r e m a n i p u l a t i o n . T h e iris r e t r a c t o r is g r a s p e d n e a r t h e h o o k e d e n d to f a c i l i t a t e i n s e r t i o n t h r o u g h the corneal incision. Once the retractor has been inserted into the anterior c h a m b e r , the n e e d l e h o l d e r is t h e n t u r n e d s o t h a t t h e r e t r a c t o r c a n h o o k t h e e d g e o f t h e iris a n d p u l l it t o w a r d t h e entry site. T h e Silastic collar can then be adjust ed to the a p p r o p r i a t e l e n g t h a n d t e n s i o n . R e m o v a l o f t h e r e t r a c t o r is a c c o m p l i s h e d b y r e v e r s i n g the s t e p s . W h e n t h e h o o k e d p o r t i o n of the r e t r a c t o r c o m e s c l o s e to t h e s e l f - s e a l i n g c o r n e a l i n c i s i o n , it will b e n d a n d s l i p o u t . It d o e s n o t r e q u i r e specific o r i e n t a t i o n as m e t a l h o o k s do. We h a v e h a d few p r o b l e m s r e l a t e d t o t h e u s e of the flexible iris r e t r a c t o r s . T h e y a r e s t r o n g
Silastic sleeves Fig. 2 (de Juan and Hickingbotham). Pupillary dilation facilitated by flexible iris retractor.
e n o u g h to b r e a k e v e n firmly a d h e r e n t s y n e c h i a e y e t flexible e n o u g h t o p r e v e n t d a m a g e to t h e a n t e r i o r c a p s u l e in p h a k i c e y e s . T h e a n t e rior c h a m b e r did flatten in o n e e y e at t h e e n d o f a fluid-gas e x c h a n g e b e c a u s e o f l e a k a g e o f a q u e o u s fluid a r o u n d t h e r e t r a c t o r . T h e c h a m b e r was reformed b y injecting b a l a n c e d salt solu tion, and the lens capsule was not d a m a g e d . This leakage can be minimized by using the knife and by using low infusion pressures dur ing t h e fluid-gas e x c h a n g e .
References 1. Eckardt, C : Pupillary stretching. A new proce dure in vitreous surgery. Retina 5:235, 1 9 8 5 . 2. Madeira, D., and Stern, W. H.: Iris suture hook for pupillary dilation in vitreoretinal surgery. Am. J. Ophthalmol. 106:743, 1 9 8 8 . 3. Zivojnovic, R.: Silicone Oil in Vitreoretinal Sur gery. Dordrecht, The Netherlands, Martinus Nijhoff Publishers, 1987, p. 126. 4. McCuen, B., Hickingbotham, D., Tsai, M., and de Juan, E., Jr.: Temporary iris fixation with a microiris retractor. Arch. Ophthalmol. 107:925, 1989. 5. Fuller, D. G., and Wilson, D. L.: Translimbal iris hook for pupillary dilation during vitreous surgery. Am. J. Ophthalmol. 110:577, 1 9 9 0 .
June, 1991
AMERICAN JOURNAL OF OPHTHALMOLOGY
a s s o c i a t e d s t r u c t u r e . If u n t r e a t e d , t h e c o n d i t i o n h e a l s , p e r s i s t s as a s u b l u x a t i o n , or p r o g r e s s e s to a frank d i s l o c a t i o n . G e n e t i c , e t h n i c , a n d u t e r i n e factors play a r o l e in its p a t h o g e n e s i s . C o n g e n i tal h i p d y s p l a s i a o c c u r s o n c e in e v e r y 1 1 0 births, with a female sex predilection of ap p r o x i m a t e l y 5 to 1. A family h i s t o r y of t h e c o n d i t i o n is n o t e d in 1 2 % to 3 3 % o f p a t i e n t s . ' Two s i s t e r s , a g e d 9 a n d 1 2 y e a r s , w e r e e x a m i n e d b y o n e of us ( P . N . ) for b l u r r e d v i s i o n a n d photophobia. They were the only children of healthy, consanguineous parents whose moth ers w e r e s i s t e r s . B o t h girls w e r e d e l i v e r e d v a g i n a l l y at t e r m a n d h a d A p g a r s c o r e s o f 9 / 9 . B o t h girls h a d b i l a t e r a l c o n g e n i t a l h i p d y s p l a s i a , r e l a t e d to an acetabular dysplasia, diagnosed by ultrasono g r a p h y at a g e 6 m o n t h s in the o l d e r s i s t e r a n d at a g e 3 m o n t h s in t h e y o u n g e r s i s t e r . T h e r e w a s n o family h i s t o r y of hip d y s p l a s i a . The younger sister had best-corrected visual a c u i t y o f 2 0 / 2 0 in e a c h eye w i t h r e f r a c t i o n o f R . E . : -1-1.00 -1-1.25 X 3 0 a n d L . E . : - 1 . 0 0 - 1 . 2 5 X 1 5 . T h e o l d e r sister h a d b e s t - c o r r e c t e d v i s u a l acuity of R.E.: 2 0 / 4 0 and L.E.: 2 0 / 3 0 with refraction of R.E.: - 2 . 0 0 - 3 . 2 5 x 4 0 and L.E.: — 1.75 - 2 . 7 5 X 3 5 . K e r a t o m e t r i c r e a d i n g s d i s c l o s e d d i s t o r t e d m i r e s in e a c h girl. B i o m i c r o scopic examination disclosed a cone-shaped e c t a s i a o f t h e c o r n e a in e a c h girl. V o g t ' s s t r i a e w e r e n o t e d in the d e e p s t r o m a a n d D e s c e m e t ' s m e m b r a n e of the o l d e r girl. T h e e n d o t h e l i a l c e l l c o u n t was w i t h i n n o r m a l l i m i t s ( 2 , 8 9 0 ± 1 2 1 c e l l s / m m ^ in the y o u n g e r s i s t e r a n d 2 , 9 1 4 ± 3 2 1 c e l l s / m m ^ in t h e o l d e r sister).^ T h e a p p e a r a n c e of t h e c o r n e a s was c o n s i s t e n t w i t h b i l a t e r al k e r a t o c o n u s . N o e v i d e n c e o f o t h e r c o r n e a l dystrophies was noted. The ophthalmic history was u n r e m a r k a b l e for a t o p i c d i s e a s e s , o c u l a r t r a u m a , eye r u b b i n g , or h a r d c o n t a c t l e n s u s e . K e r a t o c o n u s u s u a l l y b e c o m e s m a n i f e s t dur ing a d o l e s c e n c e . M o s t c a s e s o f k e r a t o c o n u s are s p o r a d i c , b u t it is s o m e t i m e s f a m i l i a l . K e n n e d y , Bourne, and D y e r ' described keratoconus oc curring in l e s s t h a n 6 % o f t h e b l o o d r e l a t i v e s o f an affected p r o b a n d . G r e e n f i e l d a n d a s s o c i a t e s * r e p o r t e d a f a m i l i a l o c c u r r e n c e of k e r a t o c o n u s and osteogenesis imperfecta and hypothesized an a u t o s o m a l r e c e s s i v e p a t t e r n o f i n h e r i t a n c e . S e v e r a l s y s t e m i c t i s s u e d i s o r d e r s are r e p o r t e d in a s s o c i a t i o n w i t h k e r a t o c o n u s , i n c l u d i n g M a r fan's syndrome and Ehlers-Danlos s y n d r o m e . ' R e p o r t s of c o n s a n g u i n i t y h a v e b e e n c i t e d as evidence of a recessive mode of inheritance. Wynne-Davies" suggested a multiple gene he r e d i t y defect in c o n g e n i t a l h i p d y s p l a s i a w i t h acetabular dysplasia, especially when environ m e n t a l factors h a d n o t played a r o l e .
T h e i n c i d e n c e of k e r a t o c o n u s r a n g e s from 5 0 to 2 0 0 p e r 1 0 0 , 0 0 0 live b i r t h s , w h e r e a s c o n g e n ital h i p d y s p l a s i a o c c u r s o n c e in 1 1 0 live b i r t h s . Therefore, congenital hip dysplasia and kerato c o n u s is an a s s o c i a t i o n o f two i n d e p e n d e n t e v e n t s w h o s e i n c i d e n c e r a n g e s from 4 to 1 8 p e r 1 , 0 0 0 , 0 0 0 live b i r t h s . M a t h e m a t i c a l l y , t h e p r o b a b i l i t y t h a t t h i s a s s o c i a t i o n o c c u r s t w i c e by c h a n c e is e x t r e m e l y l o w . T h e e a r l y d e v e l o p m e n t of k e r a t o c o n u s a n d t h e c o n s a n g u i n i t y o f t h e p a r e n t s s u p p o r t t h e h y p o t h e s i s t h a t this is m o s t l i k e l y an a u t o s o m a l r e c e s s i v e a s s o c i a t i o n .
References 1. Coleman, S. S.: Diagnosis of congenital dyspla sia of the hip in the newborn infant. Clin. Orthop. 247:3, 1989. 2. Nucci, P., Brancato, R., Mets, Μ. Β., and Shevell, S. Κ.: Normal endothelial cell density range in childhood. Arch. Ophthalmol. 108:247, 1990. 3. Kennedy, R. H., Bourne, W. M., and Dyer, J. Α.: A 48-year clinical and epidemiologic study of kerato conus. Am. J. Ophthalmol. 101:267, 1986. 4. Greenfield, G., Romano, Α., Stein, R., and Goodman, R. M.: Blue sclera and keratoconus. Key features of a distinct heritable disorder of connective tissue. Clin. Genet. 4:8, 1 9 7 3 . 5. Wynne-Davies, R.: Acetabular dysplasia and fa milial joint laxity. Two etiological factors in congeni tal dislocation of the hip. A review of 589 patients and their families. J. Bone Joint Surg. [Br.J 52:704, 1970.
Flexible Iris R e t r a c t o r Eugene de Juan, Jr., M.D., and Dyson Hickingbotham Department of Ophthalmology, Duke University Eye Center. Duke University will receive royalties based on the sale of the iris retractors; however, the authors will receive no direct compensation. Inquiries to Eugene de Juan, Jr., M.D., Dulce Eye Center, Box 3802, Durham, NC 27710.
University
I n a d e q u a t e p u p i l l a r y d i l a t i o n can o c c u r dur ing o c u l a r s u r g e r y or a s a r e s u l t o f s c a r r i n g n e a r t h e p u p i l l a r y m a r g i n from m a n y c a u s e s . A vari ety o f m e t h o d s h a v e b e e n d e v e l o p e d t o c o r r e c t this p r o b l e m , i n c l u d i n g iris s p h i n c t e r o t o m y , s e v e r a l s u t u r e t e c h n i q u e s , " m e t a l iris r e t r a c tors p l a c e d e i t h e r t h r o u g h t h e p a r s p l a n a or t h e c o r n e o s c l e r a l limbus,'''^ a n d pharmacologic m e t h o d s . N o n e o f t h e s e m e t h o d s , h o w e v e r , are sufficiently d e l i c a t e for u s e in t h e p h a k i c e y e w h e n t h e l e n s is to b e r e t a i n e d . T h e i n f l e x i b l e
Vol. I l l , No. 6
777
Letters to the Journal
Flexible Iris Retractors
Fig. 1 (de Juan and Hickingbotham). Scanning electron micrograph of flexible iris retractor showing Silastic sleeve and hook. m e t a l iris r e t r a c t o r c a n d a m a g e t h e a n t e r i o r l e n s capsule, particularly when manipulation o f the globe causes the end of the retractor to push a g a i n s t t h e d e l i c a t e i n t r a o c u l a r t i s s u e s . To o v e r come these limitations, we developed and test ed a n e w iris r e t r a c t o r w i t h a flexible n y l o n h o o k a n d a S i l a s t i c s l e e v e . T h e r e t r a c t o r is 6 . 0 m m in l e n g t h a n d h a s a 1 . 0 - m m h o o k at t h e e n d . T h e s m a l l S i l a s t i c disk h o l d s t h e r e t r a c t o r in place (Fig. 1 ) . S i n c e b o t h t h e tip a n d t h e shaft of t h e r e t r a c tor are flexible, d a m a g e to o c u l a r s t r u c t u r e s is m i n i m a l , p a r t i c u l a r l y to t h e a n t e r i o r c a p s u l e i n p h a k i c e y e s . P l a c e m e n t o f t h e r e t r a c t o r is facili tated b y a s p e c i a l l y d e v e l o p e d 0 . 5 - m m s p a t u l a shaped knife, which makes a self-sealing limbal i n c i s i o n . T h e flexible iris r e t r a c t o r s a r e c o m p a t i ble with sutured-on contact lens rings used d u r i n g v i t r e o u s s u r g e r y a n d c a n b e c u t t o any l e n g t h to avoid i n t e r f e r e n c e w i t h a n t e r i o r s e g ment manipulations (Fig. 2 ) . T h e flexible iris r e t r a c t o r is p l a c e d a n d h e l d b y a s m a l l n e e d l e h o l d e r for s e c u r e m a n i p u l a t i o n . T h e iris r e t r a c t o r is g r a s p e d n e a r t h e h o o k e d e n d to f a c i l i t a t e i n s e r t i o n t h r o u g h the corneal incision. Once the retractor has been inserted into the anterior c h a m b e r , the n e e d l e h o l d e r is t h e n t u r n e d s o t h a t t h e r e t r a c t o r c a n h o o k t h e e d g e o f t h e iris a n d p u l l it t o w a r d t h e entry site. T h e Silastic collar can then be adjust ed to the a p p r o p r i a t e l e n g t h a n d t e n s i o n . R e m o v a l o f t h e r e t r a c t o r is a c c o m p l i s h e d b y r e v e r s i n g the s t e p s . W h e n t h e h o o k e d p o r t i o n of the r e t r a c t o r c o m e s c l o s e to t h e s e l f - s e a l i n g c o r n e a l i n c i s i o n , it will b e n d a n d s l i p o u t . It d o e s n o t r e q u i r e specific o r i e n t a t i o n as m e t a l h o o k s do. We h a v e h a d few p r o b l e m s r e l a t e d t o t h e u s e of the flexible iris r e t r a c t o r s . T h e y a r e s t r o n g
Silastic sleeves Fig. 2 (de Juan and Hickingbotham). Pupillary dilation facilitated by flexible iris retractor.
e n o u g h to b r e a k e v e n firmly a d h e r e n t s y n e c h i a e y e t flexible e n o u g h t o p r e v e n t d a m a g e to t h e a n t e r i o r c a p s u l e in p h a k i c e y e s . T h e a n t e rior c h a m b e r did flatten in o n e e y e at t h e e n d o f a fluid-gas e x c h a n g e b e c a u s e o f l e a k a g e o f a q u e o u s fluid a r o u n d t h e r e t r a c t o r . T h e c h a m b e r was reformed b y injecting b a l a n c e d salt solu tion, and the lens capsule was not d a m a g e d . This leakage can be minimized by using the knife and by using low infusion pressures dur ing t h e fluid-gas e x c h a n g e .
References 1. Eckardt, C : Pupillary stretching. A new proce dure in vitreous surgery. Retina 5:235, 1 9 8 5 . 2. Madeira, D., and Stern, W. H.: Iris suture hook for pupillary dilation in vitreoretinal surgery. Am. J. Ophthalmol. 106:743, 1 9 8 8 . 3. Zivojnovic, R.: Silicone Oil in Vitreoretinal Sur gery. Dordrecht, The Netherlands, Martinus Nijhoff Publishers, 1987, p. 126. 4. McCuen, B., Hickingbotham, D., Tsai, M., and de Juan, E., Jr.: Temporary iris fixation with a microiris retractor. Arch. Ophthalmol. 107:925, 1989. 5. Fuller, D. G., and Wilson, D. L.: Translimbal iris hook for pupillary dilation during vitreous surgery. Am. J. Ophthalmol. 110:577, 1 9 9 0 .