Binocular Fusion and Stereopsis Associated With Early Surgery for Monocular Congenital Cataracts Kenneth W.
Wright, MD;
Ellen
Matsumoto, OD; Paula M. Edelman, CO
\s=b\ Despite improved visual acuity results in infants undergoing early surgery for monocular congenital cataracts, virtually all reports indicate a lack of binocular vision and the presence of strabismus in these patients. We report herein the presence of motor fusion and stereopsis in patients who have undergone early surgery for monocular congenital cataracts. Of 13 patients with congenital cataracts who were operated on by age 9 weeks, five (38%) had essentially straight eyes and evidence of motor fusion with a minimum of 1 year of follow-up. Three (60%) of five patients demonstrated sensory fusion, two with Titmus testing and one with Randot Stereo Acuity (Stereo Optical Co Inc, Chicago,III) of 250 seconds of arc. We conclude that binocular fusion and stereo visual acuity are obtainable in patients with monocular congenital cataracts.
(Arch Ophthalmol. 1992;110:1607-1609) "M'ormai neural development of binoc^ ular cortical cells requires clear and equal retinal images during the crit¬ ical period of visual development.14 Ba¬ sic science research has documented that unilateral image blur during the early period of visual development re¬ sults in loss of binocular function.5"8 These data are substantiated by clinical experience that shows that patients with unilateral congenital cataracts do not obtain binocular fusion or stereopsis even when the monocular visual acuity outcome is favorable.9,10 Despite im¬ proved visual acuity in infants undergo¬ ing early surgery for monocular congen¬ ital cataracts, virtually all reports indi¬ cate a lack of binocular vision and the presence of strabismus in patients with monocular congenital cataracts.1114 We report herein the presence of binocular
Accepted for publication July 21, 1992. From the Department of Ophthalmology, University of Southern California School of Medicine, Los Angeles (Dr Wright), and the Department of Ophthalmology, Childrens Hospital Los Angeles (Drs Wright and Matsumoto and Ms Edelman). Reprint requests to 2601 Airport Dr, Torrance, CA 90505 (Dr Wright).
vision and stereopsis in patients who have undergone early surgery for mo¬ nocular congenital cataracts. PATIENTS AND METHODS The medical records of 146 consecutive
patients who were operated on for monocu¬ lar cataracts at Childrens Hospital Los An¬ geles (Calif) between 1983 and 1990 were re¬ viewed. Of the 146 patients, 33 (23%) had undergone cataract surgery by age 9 weeks for a monocular congenital cataract. Thir¬ teen (39%) of the 33 patients who underwent early surgery met the following inclusion criteria for this study: (1) cataract surgery performed by age 9 weeks, (2) at least 1 year of follow-up, (3) normal posterior pole anat¬ omy, and (4) congenital onset of cataract. In addition, patients with persistent hy¬ perplastic primary vitreous, posterior lenti¬ conus, or traumatic cataracts or other cata¬ racts that were potentially progressive were
excluded. The goal of the inclusion criteria to restrict the study to truly congenital monocular cataracts that were visually sig¬ nificant during the critical period of visual was
development. All patients underwent a limbal lensec¬ tomy with anterior vitrectomy. After sur¬
gery, the patients were fitted with aphakic contact lenses as soon as possible, with a mean interval of 8 days and a range of 1 to 14 days. The contact lenses were worn on an extended-wear basis for the first 6 months, and were then worn on a flexible basis. Oc¬ clusion therapy consisted of daily patching of the sound eye for 1 hour during the first month, 2 hours during the second month, and 3 hours during the third month, with patch¬ ing not to exceed 50% of waking hours dur¬ ing the first 6 months of life15 (Table 1). One patient (patient 1) was unavailable for follow-up for approximately 1 year and did not adhere to the patching regimen, but did maintain use of the contact lens. Follow-up visits were scheduled approxi¬ mately every 2 months for evaluation of con¬ tact lens power, fit, and tolerance. A fully di¬ lated eye examination and intraocular pressure assessment were performed at 6-month intervals. Visual acuity was as¬ sessed in preverbal infants by measurement of central fixation and/or use of the vertical prism test.16 In verbal children, hand-held Allen cards, linear Allen pictures, and Snellen letters were used to determine vi¬ sual acuity. Ocular alignment was measured with cover-uncover testing. Motor fusion
Downloaded From: http://archopht.jamanetwork.com/ by a Oakland University User on 06/06/2015
assessed by identifying the presence of phoria and by measuring fusional conver¬ gence amplitudes using a prism bar. Sensory was a
fusion in verbal children was evaluated with the Worth 4 Dot (Stereo Optical Co Ine) at distance and near, Titmus stereo testing, and Randot stereo testing.
RESULTS
Of the 13 patients studied, eight (62%) showed a good visual outcome, with acu¬ ities of20/60 or better in the operated-on eye; in children too young to cooperate with optotype visual acuity, accurate central fixation to small toys and to small objects was considered a good visual re¬ sult. Four (50%) of the eight patients with a good visual result cooperated with optotype acuity testing and their visual acuities ranged from 20/60 to 20/40. Strabismus (defined as a tropia of 10
prism diopters [pD] or more) was present in five patients, three with esotropia and two with exotropia. Eight patients showed deviations of less than 10 pD. Five (62%) of the eight patients demon¬
strated motor fusion with convergence
testing, while three patients (38%)
showed no motor or sensory fusion. The fusional vergence amplitudes for these five patients ranged from 16 through 20 pD of convergence to base-out prism. Sensory testing revealed fusion to Tit¬ mus testing in three of the five patients (Figure), while two were too young to co¬ operate with sensory testing. In one pa¬ tient (patient 3), stereo visual acuity with Titmus testing measured 200 seconds of arc and the patient also had stereopsis to Randot testing of 250 seconds of arc. Table 2 shows the five patients who showed fusion after early surgery for Table
1.—Patching Regimen
Patient
Age,
mo
0-1 1-2 2-4 4-12
a12
Occlusion No patching 1 h/d 2-3 h/d 50% ot waking hours as indicated Up to 80% of waking hours as indicated
monocular
congenital cataract. Inter¬ estingly, patient 1, who showed both motor and sensory fusion, had a rela¬ tively poor monocular visual acuity (20/70 Allen-card equivalent). This pa¬ tient left the United States immediately
after surgery and did not use monocular occlusion for 1 year; however, the pa¬ tient did continue using the contact lens on an extended-wear basis. After re¬ turning at age 2 years, the patient un¬ derwent part-time occlusion therapy to achieve final visual acuity of 20/70. COMMENT
In this report, we described five chil¬ dren who showed evidence of binocularity and fusion after early surgery for uni¬ lateral congenital cataracts. There is a large volume of literature on the topic of congenital cataracts, but few reports have addressed the incidence of binocularity and fusion in patients who have un¬ dergone early treatment for unilateral congenital cataracts.914 Pratt-Johnson and Tillson10 described four patients who had undergone surgery for congenital cataracts and who achieved a good visual result of 20/40 or better. Despite the good visual acuity, all patients showed si¬ multaneous perception but no real fusion. Cheng et al11 recently reported re¬ sults in 25 consecutive patients with unilateral congenital cataracts. All 25 patients in that study had strabismus after surgery, with 16 developing es¬ otropia and nine developing exotropia. In the present study, we identified five (38%) of 13 patients who underwent early surgery for congenital monocular cataracts and developed evidence of fusion. All five patients showed motor fusion with convergence amplitudes. Three (60%) of the five patients also showed sensory fusion, two with Tit¬ mus testing and one with Titmus and Randot stereo acuity testing. Assessment of stereo acuity with Tit¬ mus testing can be misleading. Some patients without binocular vision use monocular clues to identify which of the Titmus circles or animals is a stereogram. Monocular clues used to find the stereogram include lateral displace¬ ment17,18 and image jump in patients who alternate fixation.19 Our three pa¬ tients with a positive fly on Titmus testing, however, identified the fly wings off the surface of the book, which is indicative of stereopsis. Our results stand alone in the litera¬ we recently were con¬ by Fred M. Gregg, MD (written communication, December 4, 1991), an ophthalmologist who also treated a pa¬ tient who had undergone surgery for congenital cataract (in the first week of life) and had binocularity and fusion. The
ture; however, tacted
Photographs of three patients in our study who had stereopsis demonstrated on sensory test¬ ing are shown. Top, Patient 1 had straight eyes and peripheral fusion despite relatively poor visual outcome since she did not use the patch during the first year of life, yet wore the contact lens full time. The smaller right eye is the aphakic eye. Center, Patient 2 had a small cornea in the aphakic left eye, yet achieved a visual acuity of 20/40 OS and stereo acuity with Titmus testing. Bottom, Patient 3 had an aphakic left eye as well as microcornea. This patient achieved a visual acuity of 20/30 OS and stereopsis to both Titmus and Randot testing. cataract was identified at birth and bi¬ lateral occlusion was immediately insti¬ tuted. Cataract surgery was performed 27 hours after birth and a contact lens was immediately fitted. After an 8-year follow-up the patient showed monocular visual acuity of 20/25, a fusion of Worth 4 Dot at distance and near, and stereo acuity of 50 seconds of arc with Titmus
Downloaded From: http://archopht.jamanetwork.com/ by a Oakland University User on 06/06/2015
testing. Initial postoperative patching of the phakic eye was done for 1 hour per day for every month of age. Why is it that these patients achieved binocularity and fusion when others have not? In the study by Cheng et al,11 none of the patients achieved fusion and all had strabismus after surgery. More than one third of their patients under-
Table 2.—Five Patients With Fusion* Patient No./
Diagnosis 1 /congenital cataract
Age at Surgery, wk
Motor Fusion
Visual Acuity 20/70 LAF
Deviation at Near E8
diopters
Orthotropia
20 prism BO
diopters
Orthotropia
16
2/congenital
cataract
20/30 Snellen
X8
3/congenital
cataract
20/40+ LAF
Orthotropia
4/congenital
cataract
5/congenital
cataract
*LAF indicates linear Allen
figure;
Fixes right eye; no hold left eye Fixes left eye; no hold right eye E8, esophoria of 8 prism
went surgery after age 17 weeks and the mean delay between surgery and con¬ tact lens use was 30 days. In addition,
the occlusion therapy for amblyopia con¬ sisted of 24-hour-a-day patching in chil¬ dren younger than age 1 year. Birch and Stager12 also suggested extensive patching during the first months of life, and they prescribed patching for all but 2 waking hours per day for children younger than age 6 months. While unilateral patching may be good for monocular visual acuity, it is probably very bad with regard to the early development of binocularity and fusion. It is now well known that binoc¬ ularity and motor fusion occur early, probably by the first 2 to 4 months of life.20-22 It is likely, therefore, that fulltime or extensive patching therapy dur¬ ing the first few months of life would interfere with binocular visual develop¬ ment. The argument is, however, that if we do not aggressively occlude the good
diopters; BO,
Sensory Fusion fly
Amplitude diopters
20 prism BO 20 prism BO 19 prism BO
Titmus
diopters
prism diopters
Titmus fly Worth 4 Dot fuses Titmus 200 s, 2 of 3 animals, Randot 250 s Unable
4 y 8
mo
3 y 6
mo
1 y4
mo
Unable
1 y 5 mo
BO
base out; and X8,
exophoria
eye, severe and irreversible amblyopia will occur. O'Dell et al23 showed that, in the mon¬ key, immediate correction of neonatal aphakia with 50% occlusion ofthe phakic eye results in similar visual acuity de¬ velopment for both eyes. Our study ver¬ ified that full-time or near full-time oc¬ clusion therapy is not necessary to achieve excellent monocular visual acu¬ ity. Patients 2 and 3 achieved visual acu¬ ities of 20/30 and 20/40+ and binocular fusion with a patching regimen of no more than 50% during the first 6 months of life. Patient 1, however, demon¬ strated that occlusion therapy is neces¬ sary since this patient was fitted with and wore the contact lens well, but did not use patching during the first year of life. This patient developed peripheral fusion of the monofixation type, but mo¬ nocular visual acuity was relatively poor, measuring approximately 20/70. Development of binocularity appears
of 8
Age at Testing 3y
prism diopters.
fragile, occurring early in vi¬ development. Because of tiris, we suggest immediate bilateral patching in
to be very
sual
infants younger than age 4 months who present with a visually significant con¬ genital cataract.24 Bilateral patching re¬ tards the abnormal visual processing caused by the blurred retinal image as¬ sociated with the cataract and pro¬ longs the critical period of visual
development.24-26
We conclude that patients with monoc¬ ular congenital cataracts can achieve bin¬ ocularity and fusion. Factors that may en¬ hance the development of binocularity in¬ clude the following: (1) early surgery with immediate contact lens fitting, (2) binoc¬ ular occlusion for image "blur" between the time of detection of the cataract and establishment of a clear retinal image by the contact lens, and (3) judicious patch¬ ing of the phakic eye during the first 6 months of life, with occlusion therapy during no more than 50% of waking hours.
References 1. Wiesel TN, Hubel DH. Single-cell responses in striate cortex of kittens deprived of vision in one eye. J Neurophysiol. 1963;26:1003-1017. 2. Ikeda H, Tremain KE. Amblyopia resulting from penalisation: neurophysiological studies of kittens reared with atropinisation of one or both eyes. Br J Ophthalmol. 1978;62:21-28. 3. Hendrickson AE, Movshon JA, Eggers HM, Gizzi MS, Boothe RG, Kiorpes L. Effects of early unilateral blur on the macaque's visual system, II: anatomical observations. J Neurosci. 1987;7:1327-1339. 4. von Noorden GK, Crawford MLJ. Form vision deprivation without light deprivation produces the visual deprivation syndrome in Macaca mulatta. Brain Res. 1977;129:37-44. 5. Movshon JA, Eggers HM, Gizzi MS, Hendrickson AE, Kiorpes L, Boothe RG. Effects of early unilateral blur on the macaque's visual system, III: physiological observations. J Neurosci.
1987;7:1340-1351. 6. Ikeda H, Tremain K. Amblyopia and cortical binocularity. Trans Ophthalmol Soc U K. 1980;100:
450-452. 7. Hubel DH, Wiesel TN. The period of susceptibility to the physiological effects of unilateral eye closure in kittens. J Physiol. 1970;206:419-436. 8. von Noorden GK, Crawford MLJ. The effects of total unilateral occlusion versus lid suture on the visual system of infant monkeys. Invest Ophthal-
mol Vis Sci. 1981;21:142-146. 9. Beller R, Hoyt CS, Marg E, Odom JV. Good visual function after neonatal surgery for congenital monocular cataracts. Am J Ophthalmol. 1981; 91:559-565. 10. Pratt-Johnson JA, Tillson G. Unilateral congenital cataract: binocular status after treatment. Pediatr Ophthalmol Strabismus. 1989;26:72-75. 11. Cheng KP, Hiles DA, Biglan AW, Pettapiece MC. Visual results after early surgical treatment of unilateral congenital cataracts. Ophthalmology. J
1991;98:903-910. 12. Birch EE, Stager DR. Prevalence of good visual acuity following surgery for congenital unilateral cataract. Arch Ophthalmol. 1988;106:40-43.
13. Parks MM. Visual results in aphakic children. Am J Ophthalmol. 1982;94:441-449. 14. France TD, Frank JW. The association of strabismus and aphakia in children. J Pediatr Ophthalmol Strabismus. 1984;21:223-226. 15. Wright KW. Management of amblyopia associated with congenital cataracts. POS Int Survey. 1991:27-34. 16. Wright KW. Reliability of fixation preference testing in diagnosing amblyopia. Arch Ophthalmol. 1986;104:549-553. 17. Reinecke RD, Simons K. A new stereoscopic test for amblyopia screening. Am J Ophthalmol.
1974;78:714-721.
Downloaded From: http://archopht.jamanetwork.com/ by a Oakland University User on 06/06/2015
18. Clarke WN, Noel LP. Stereoacuity testing in the monofixation syndrome. J Pediatr Ophthalmol Strabismus. 1990;27:161-163. 19. Archer SM. Stereotest artifacts and the strabismus patient. Graefes Arch Clin Exp Ophthalmol. 1988;226:313-316. 20. ArcherSM,SondhiN,HelvestonEM.Strabisin infancy. Ophthalmology. 1989;96:133-137. 21. Birch EE, Shimojo S, Held R. Preferential looking assessment of fusion and stereopsis in infants aged 1-6 months. Invest Ophthalmol Vis
mus
Sci. 1985;26:366-370. 22. Mohindra I, Zwaan J, Held R, Brill S, Zwaan F. Development of acuity and stereopsis in infants with esotropia. Ophthalmology. 1985; 95:691-697. 23. O'Dell CD, Gammon JA, Fernandez A, Wilson JR, Boothe RG. Development of acuity in a primate model of human infantile unilateral aphakia. Invest Ophthalmol Vis Sci. 1989;30:2068-2074. 24. Wright KW, Wehrle MJ, Urrea PT. Bilateral total occlusion during the critical period of visual
development. Arch Ophthalmol. 1987;105:321. 25. Cynader M, Derman N, Hein A. Recovery of function in cat visual cortex following prolonged deprivation. Exp Brain Res. 1976;25:139-156. 26. Hoyt CS. The long-term visual effects of short-term binocular occlusion of at-risk neonates. Arch Ophthalmol. 1980;98:1967-1970.
Wright, MD;
Ellen
Matsumoto, OD; Paula M. Edelman, CO
\s=b\ Despite improved visual acuity results in infants undergoing early surgery for monocular congenital cataracts, virtually all reports indicate a lack of binocular vision and the presence of strabismus in these patients. We report herein the presence of motor fusion and stereopsis in patients who have undergone early surgery for monocular congenital cataracts. Of 13 patients with congenital cataracts who were operated on by age 9 weeks, five (38%) had essentially straight eyes and evidence of motor fusion with a minimum of 1 year of follow-up. Three (60%) of five patients demonstrated sensory fusion, two with Titmus testing and one with Randot Stereo Acuity (Stereo Optical Co Inc, Chicago,III) of 250 seconds of arc. We conclude that binocular fusion and stereo visual acuity are obtainable in patients with monocular congenital cataracts.
(Arch Ophthalmol. 1992;110:1607-1609) "M'ormai neural development of binoc^ ular cortical cells requires clear and equal retinal images during the crit¬ ical period of visual development.14 Ba¬ sic science research has documented that unilateral image blur during the early period of visual development re¬ sults in loss of binocular function.5"8 These data are substantiated by clinical experience that shows that patients with unilateral congenital cataracts do not obtain binocular fusion or stereopsis even when the monocular visual acuity outcome is favorable.9,10 Despite im¬ proved visual acuity in infants undergo¬ ing early surgery for monocular congen¬ ital cataracts, virtually all reports indi¬ cate a lack of binocular vision and the presence of strabismus in patients with monocular congenital cataracts.1114 We report herein the presence of binocular
Accepted for publication July 21, 1992. From the Department of Ophthalmology, University of Southern California School of Medicine, Los Angeles (Dr Wright), and the Department of Ophthalmology, Childrens Hospital Los Angeles (Drs Wright and Matsumoto and Ms Edelman). Reprint requests to 2601 Airport Dr, Torrance, CA 90505 (Dr Wright).
vision and stereopsis in patients who have undergone early surgery for mo¬ nocular congenital cataracts. PATIENTS AND METHODS The medical records of 146 consecutive
patients who were operated on for monocu¬ lar cataracts at Childrens Hospital Los An¬ geles (Calif) between 1983 and 1990 were re¬ viewed. Of the 146 patients, 33 (23%) had undergone cataract surgery by age 9 weeks for a monocular congenital cataract. Thir¬ teen (39%) of the 33 patients who underwent early surgery met the following inclusion criteria for this study: (1) cataract surgery performed by age 9 weeks, (2) at least 1 year of follow-up, (3) normal posterior pole anat¬ omy, and (4) congenital onset of cataract. In addition, patients with persistent hy¬ perplastic primary vitreous, posterior lenti¬ conus, or traumatic cataracts or other cata¬ racts that were potentially progressive were
excluded. The goal of the inclusion criteria to restrict the study to truly congenital monocular cataracts that were visually sig¬ nificant during the critical period of visual was
development. All patients underwent a limbal lensec¬ tomy with anterior vitrectomy. After sur¬
gery, the patients were fitted with aphakic contact lenses as soon as possible, with a mean interval of 8 days and a range of 1 to 14 days. The contact lenses were worn on an extended-wear basis for the first 6 months, and were then worn on a flexible basis. Oc¬ clusion therapy consisted of daily patching of the sound eye for 1 hour during the first month, 2 hours during the second month, and 3 hours during the third month, with patch¬ ing not to exceed 50% of waking hours dur¬ ing the first 6 months of life15 (Table 1). One patient (patient 1) was unavailable for follow-up for approximately 1 year and did not adhere to the patching regimen, but did maintain use of the contact lens. Follow-up visits were scheduled approxi¬ mately every 2 months for evaluation of con¬ tact lens power, fit, and tolerance. A fully di¬ lated eye examination and intraocular pressure assessment were performed at 6-month intervals. Visual acuity was as¬ sessed in preverbal infants by measurement of central fixation and/or use of the vertical prism test.16 In verbal children, hand-held Allen cards, linear Allen pictures, and Snellen letters were used to determine vi¬ sual acuity. Ocular alignment was measured with cover-uncover testing. Motor fusion
Downloaded From: http://archopht.jamanetwork.com/ by a Oakland University User on 06/06/2015
assessed by identifying the presence of phoria and by measuring fusional conver¬ gence amplitudes using a prism bar. Sensory was a
fusion in verbal children was evaluated with the Worth 4 Dot (Stereo Optical Co Ine) at distance and near, Titmus stereo testing, and Randot stereo testing.
RESULTS
Of the 13 patients studied, eight (62%) showed a good visual outcome, with acu¬ ities of20/60 or better in the operated-on eye; in children too young to cooperate with optotype visual acuity, accurate central fixation to small toys and to small objects was considered a good visual re¬ sult. Four (50%) of the eight patients with a good visual result cooperated with optotype acuity testing and their visual acuities ranged from 20/60 to 20/40. Strabismus (defined as a tropia of 10
prism diopters [pD] or more) was present in five patients, three with esotropia and two with exotropia. Eight patients showed deviations of less than 10 pD. Five (62%) of the eight patients demon¬
strated motor fusion with convergence
testing, while three patients (38%)
showed no motor or sensory fusion. The fusional vergence amplitudes for these five patients ranged from 16 through 20 pD of convergence to base-out prism. Sensory testing revealed fusion to Tit¬ mus testing in three of the five patients (Figure), while two were too young to co¬ operate with sensory testing. In one pa¬ tient (patient 3), stereo visual acuity with Titmus testing measured 200 seconds of arc and the patient also had stereopsis to Randot testing of 250 seconds of arc. Table 2 shows the five patients who showed fusion after early surgery for Table
1.—Patching Regimen
Patient
Age,
mo
0-1 1-2 2-4 4-12
a12
Occlusion No patching 1 h/d 2-3 h/d 50% ot waking hours as indicated Up to 80% of waking hours as indicated
monocular
congenital cataract. Inter¬ estingly, patient 1, who showed both motor and sensory fusion, had a rela¬ tively poor monocular visual acuity (20/70 Allen-card equivalent). This pa¬ tient left the United States immediately
after surgery and did not use monocular occlusion for 1 year; however, the pa¬ tient did continue using the contact lens on an extended-wear basis. After re¬ turning at age 2 years, the patient un¬ derwent part-time occlusion therapy to achieve final visual acuity of 20/70. COMMENT
In this report, we described five chil¬ dren who showed evidence of binocularity and fusion after early surgery for uni¬ lateral congenital cataracts. There is a large volume of literature on the topic of congenital cataracts, but few reports have addressed the incidence of binocularity and fusion in patients who have un¬ dergone early treatment for unilateral congenital cataracts.914 Pratt-Johnson and Tillson10 described four patients who had undergone surgery for congenital cataracts and who achieved a good visual result of 20/40 or better. Despite the good visual acuity, all patients showed si¬ multaneous perception but no real fusion. Cheng et al11 recently reported re¬ sults in 25 consecutive patients with unilateral congenital cataracts. All 25 patients in that study had strabismus after surgery, with 16 developing es¬ otropia and nine developing exotropia. In the present study, we identified five (38%) of 13 patients who underwent early surgery for congenital monocular cataracts and developed evidence of fusion. All five patients showed motor fusion with convergence amplitudes. Three (60%) of the five patients also showed sensory fusion, two with Tit¬ mus testing and one with Titmus and Randot stereo acuity testing. Assessment of stereo acuity with Tit¬ mus testing can be misleading. Some patients without binocular vision use monocular clues to identify which of the Titmus circles or animals is a stereogram. Monocular clues used to find the stereogram include lateral displace¬ ment17,18 and image jump in patients who alternate fixation.19 Our three pa¬ tients with a positive fly on Titmus testing, however, identified the fly wings off the surface of the book, which is indicative of stereopsis. Our results stand alone in the litera¬ we recently were con¬ by Fred M. Gregg, MD (written communication, December 4, 1991), an ophthalmologist who also treated a pa¬ tient who had undergone surgery for congenital cataract (in the first week of life) and had binocularity and fusion. The
ture; however, tacted
Photographs of three patients in our study who had stereopsis demonstrated on sensory test¬ ing are shown. Top, Patient 1 had straight eyes and peripheral fusion despite relatively poor visual outcome since she did not use the patch during the first year of life, yet wore the contact lens full time. The smaller right eye is the aphakic eye. Center, Patient 2 had a small cornea in the aphakic left eye, yet achieved a visual acuity of 20/40 OS and stereo acuity with Titmus testing. Bottom, Patient 3 had an aphakic left eye as well as microcornea. This patient achieved a visual acuity of 20/30 OS and stereopsis to both Titmus and Randot testing. cataract was identified at birth and bi¬ lateral occlusion was immediately insti¬ tuted. Cataract surgery was performed 27 hours after birth and a contact lens was immediately fitted. After an 8-year follow-up the patient showed monocular visual acuity of 20/25, a fusion of Worth 4 Dot at distance and near, and stereo acuity of 50 seconds of arc with Titmus
Downloaded From: http://archopht.jamanetwork.com/ by a Oakland University User on 06/06/2015
testing. Initial postoperative patching of the phakic eye was done for 1 hour per day for every month of age. Why is it that these patients achieved binocularity and fusion when others have not? In the study by Cheng et al,11 none of the patients achieved fusion and all had strabismus after surgery. More than one third of their patients under-
Table 2.—Five Patients With Fusion* Patient No./
Diagnosis 1 /congenital cataract
Age at Surgery, wk
Motor Fusion
Visual Acuity 20/70 LAF
Deviation at Near E8
diopters
Orthotropia
20 prism BO
diopters
Orthotropia
16
2/congenital
cataract
20/30 Snellen
X8
3/congenital
cataract
20/40+ LAF
Orthotropia
4/congenital
cataract
5/congenital
cataract
*LAF indicates linear Allen
figure;
Fixes right eye; no hold left eye Fixes left eye; no hold right eye E8, esophoria of 8 prism
went surgery after age 17 weeks and the mean delay between surgery and con¬ tact lens use was 30 days. In addition,
the occlusion therapy for amblyopia con¬ sisted of 24-hour-a-day patching in chil¬ dren younger than age 1 year. Birch and Stager12 also suggested extensive patching during the first months of life, and they prescribed patching for all but 2 waking hours per day for children younger than age 6 months. While unilateral patching may be good for monocular visual acuity, it is probably very bad with regard to the early development of binocularity and fusion. It is now well known that binoc¬ ularity and motor fusion occur early, probably by the first 2 to 4 months of life.20-22 It is likely, therefore, that fulltime or extensive patching therapy dur¬ ing the first few months of life would interfere with binocular visual develop¬ ment. The argument is, however, that if we do not aggressively occlude the good
diopters; BO,
Sensory Fusion fly
Amplitude diopters
20 prism BO 20 prism BO 19 prism BO
Titmus
diopters
prism diopters
Titmus fly Worth 4 Dot fuses Titmus 200 s, 2 of 3 animals, Randot 250 s Unable
4 y 8
mo
3 y 6
mo
1 y4
mo
Unable
1 y 5 mo
BO
base out; and X8,
exophoria
eye, severe and irreversible amblyopia will occur. O'Dell et al23 showed that, in the mon¬ key, immediate correction of neonatal aphakia with 50% occlusion ofthe phakic eye results in similar visual acuity de¬ velopment for both eyes. Our study ver¬ ified that full-time or near full-time oc¬ clusion therapy is not necessary to achieve excellent monocular visual acu¬ ity. Patients 2 and 3 achieved visual acu¬ ities of 20/30 and 20/40+ and binocular fusion with a patching regimen of no more than 50% during the first 6 months of life. Patient 1, however, demon¬ strated that occlusion therapy is neces¬ sary since this patient was fitted with and wore the contact lens well, but did not use patching during the first year of life. This patient developed peripheral fusion of the monofixation type, but mo¬ nocular visual acuity was relatively poor, measuring approximately 20/70. Development of binocularity appears
of 8
Age at Testing 3y
prism diopters.
fragile, occurring early in vi¬ development. Because of tiris, we suggest immediate bilateral patching in
to be very
sual
infants younger than age 4 months who present with a visually significant con¬ genital cataract.24 Bilateral patching re¬ tards the abnormal visual processing caused by the blurred retinal image as¬ sociated with the cataract and pro¬ longs the critical period of visual
development.24-26
We conclude that patients with monoc¬ ular congenital cataracts can achieve bin¬ ocularity and fusion. Factors that may en¬ hance the development of binocularity in¬ clude the following: (1) early surgery with immediate contact lens fitting, (2) binoc¬ ular occlusion for image "blur" between the time of detection of the cataract and establishment of a clear retinal image by the contact lens, and (3) judicious patch¬ ing of the phakic eye during the first 6 months of life, with occlusion therapy during no more than 50% of waking hours.
References 1. Wiesel TN, Hubel DH. Single-cell responses in striate cortex of kittens deprived of vision in one eye. J Neurophysiol. 1963;26:1003-1017. 2. Ikeda H, Tremain KE. Amblyopia resulting from penalisation: neurophysiological studies of kittens reared with atropinisation of one or both eyes. Br J Ophthalmol. 1978;62:21-28. 3. Hendrickson AE, Movshon JA, Eggers HM, Gizzi MS, Boothe RG, Kiorpes L. Effects of early unilateral blur on the macaque's visual system, II: anatomical observations. J Neurosci. 1987;7:1327-1339. 4. von Noorden GK, Crawford MLJ. Form vision deprivation without light deprivation produces the visual deprivation syndrome in Macaca mulatta. Brain Res. 1977;129:37-44. 5. Movshon JA, Eggers HM, Gizzi MS, Hendrickson AE, Kiorpes L, Boothe RG. Effects of early unilateral blur on the macaque's visual system, III: physiological observations. J Neurosci.
1987;7:1340-1351. 6. Ikeda H, Tremain K. Amblyopia and cortical binocularity. Trans Ophthalmol Soc U K. 1980;100:
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