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Functional visual loss in patients with bilateral ocular coloboma
Short Reports Functional Visual Loss in Patients With Bilateral Ocular Coloboma Libe Gradstein, MD, Nadav Belfair, MD, Edna Ronen, Tova Lifshitz, MD, and BenZion Biedner, MD Coloboma is a common ocular malformation, with a prevalence of 0.7 per 10,000 newborns.1 It varies from a small asymptomatic defect to a microphthalmic cystic eye with profound visual loss.2-4 Microphthalmos, microcornea, and involvement of the fovea, optic nerve, and papulomacular bundle have been reported to correlate with poor vision in patients with coloboma.2,4-8 It has been noted that refractive errors often accompany colobomata and can cause a superimposed anisometropic amblyopia, especially in unilateral cases.2,4,6-8 However, to the best of our knowledge, the role of amblyopia has not been systematically assessed in patients with bilateral colobomata. In this report we analyzed factors that affected vision of the members of a previously presented family with bilateral iris and chorioretinal colobomata.9 Despite the foveal sparing in all patients, visual function varied. Some had near-normal visual acuity and stereopsis, even with optic nerve involvement. Strabismic and anisometropic amblyopia was an important cause of reduced vision and, therefore, should not be overlooked.
SUBJECTS AND METHODS Six members of a family were affected by an isolated dominant coloboma, the mother (patient 1) and 5 of her 7 children (patients 2-6), totaling 5 females and 1 male, ages 8 to 43 years.9 Patients 1 through 5 underwent complete ophthalmic examinations, cycloplegic refraction, fundus photography, and measurements of axial length and corneal diameter. Patient 6 was adopted into another family and could not be located for a detailed examination. Near stereopsis was assessed by a Titmus Test (Stereo Optical Co, Inc, Chicago, Ill). Axial length was measured by an Ultrasonic Biometer (Humphrey Instruments, Inc, San Leandro, Calif) and corneal diameter by a flexible ruler. Fundus photographs were analyzed with regard to coloboma size, symmetry, and involvement of the optic nerve and fovea. We sought the relationships between
From the Department of Ophthalmology, Soroka Medical Center, The Faculty of Health Sciences, Ben Gurion University of the Negev, Beer-Sheva, Israel. Submitted January 18, 2001. Revisions accepted December 31, 2001. Reprint requests: Libe Gradstein, MD, Department of Ophthalmology, Soroka Medical Center, Beer-Sheva, Israel, 84101. J AAPOS 2002;6:195-7. Copyright © 2002 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/2002/$35.00 ⫹ 0 75/1/122679 doi:10.1067/mpa.2002.122679
Journal of AAPOS
these anatomical features and patients’ visual acuity (VA), ocular alignment, stereopsis, and refractive errors.
RESULTS All the examined patients had bilateral typical iris and chorioretinal colobomata with mild microcornea without microphthalmia (horizontal corneal diameter 8.8-9.8 mm, axial length 21.81-24.80 mm). The Table describes clinical presentation of patients 1 to 5. The defect was asymmetric in all patients. In patients 1 to 4 the sides of larger iris and chorioretinal lesion agreed. In patient 5 iris coloboma was larger in the left eye, but the chorioretinal defect was more extensive in the right eye (Figure). The optic nerve was involved in 4 patients, in each case unilaterally, in the eye with larger chorioretinal defect (Table). The fovea was spared, except splitting by the coloboma (with presence of foveal reflex) in the right eye of patient 3. Best corrected VA ranged from 6/6 to 6/36 (Table). Patients 1, 2, 3, and 5 had unequal acuities in the 2 eyes. In these patients the eye with the larger chorioretinal coloboma had the worse VA, and in 3 of them (patients 1, 3, 5) this was the eye with unilaterally affected optic nerve. In patient 4, the visual acuities were equal despite the larger chorioretinal coloboma with unilateral optic nerve involvement in the left eye. Various refractive errors necessitating optical correction, with astigmatism of at least 1.5 D, were measured in all eyes. Anisometropia of 4 to 8.5 D was detected in patients 1 and 2, both had amblyopia of the eye with the higher refractive error (higher spherical equivalent). Patients 1, 4, and 5 had exotropia, which was surgically corrected in patient 5. Patients 1 and 5 with unilateral exotropia had amblyopia of the exotropic eye. Although in these 2 patients a chorioretinal defect was larger in the exotropic eye, across patients, no association was found between the anatomical features of coloboma and presence of strabismus or anisometropia. Stereopsis of 140" was detected in patients 1 and 3, and of 40" in patient 4. Patients 1, 2, and 5 had amblyopia (a difference of 2 Snellen’s lines or more in VA between the 2 eyes) of anisometropic, strabismic, or combined origin.
DISCUSSION Similarly to other studies,2,5 colobomata were asymmetric in all our patients. Although the sides of larger iris and chorioretinal colobomata usually agreed, patient 5 had a larger chorioretinal defect in the eye with the smaller iris coloboma. This finding has not been previously reported. June 2002
195
196
Journal of AAPOS Volume 6 Number 3 June 2002
Gradstein et al
FIG 1. Iris and chorioretinal colobomata of patient 5. (A), Right eye iris coloboma. Note inferonasal lens opacities found in all eyes, which did not cover visual axis. (B), Larger iris coloboma and more lens opacities in left eye. (C), Right eye chorioretinal coloboma, which involves optic nerve and part of macular area, but not fovea. (D), Smaller chorioretinal defect in left eye limited to inferonasal quadrant, which does not involve optic nerve. Note small satellite lesion under nerve.
TABLE. Clinical findings of patients 1 through 5 Colobomatous involvement Age Pt (years) Gender
Inferonasal iris
Chorioretinal
Optic Nerve
Fovea
BCVA
Stereo acuity
Refraction
Strabismus
1
43
F
OS ⬎ OD
OS ⬎ OD OD: confluent* OS: bridge of normal retina under ON
OD: No OS: Yes
No
OD 6/7.5 OS 6/12
140“
OD ⫹ 5.75–3.00 ⫻ 95 OS ⫺ 2.75–2.75 ⫻ 65
2
15
M
OS ⬎ OD
OS ⬎ OD confluent*
No
No
OD 6/7.5 OS 6/36
None
OD ⫹ 3.00–1.50 ⫻ 5 None OS ⫺ 1.25–1.75 ⫻ 165
3
12
F
OD ⬎ OS
OD⬎OS OD: confluent* OS: with satellite†
OD: Yes OS: No
OD: splits fovea (reflex present) OS: No
OD 6/7.5 OS 6/6
140“
OD plano–3.00 ⫻ 170 OS plano–2.00 ⫻ 10
4
10
F
OS ⬎ OD
OS ⬎ OD OD: with satellite† under ON OS: bridge of normal retina under ON
OD: No OS: Yes
No
OD 6/7.5 OS 6/7.5
40“
OD ⫹ 1.00–2.50 ⫻ 160 D: Intermittent OS ⫹ 0.50–2.50 ⫻ 10 AXT 50⌬
OD ⬎ OS OD: confluent* OS: with satellite† under ON
OD: Yes OS: No
5
8
F
OS ⬎ OD
D: LXT 50⌬ N: Intermittent LXT 25⌬
None
N: Intermittent AXT 30⌬ No
OD 6/21 OS 6/7.5
None
OD ⫹ 3.50–2.50 ⫻ 150 D&N: OS ⫹ 2.50–1.50 ⫻ 160 RXT 60⌬
AXT, Alternating exotropia; BCVA, best corrected visual acuity; D, deviation for distant fixation; F, female; LXT, left exotropia; M, male; N, deviation for near fixation; OD, right eye; ON, optic nerve; OS, left eye; Pt, patient; RXT, right exotropia. *Coloboma without intervening areas of normal retina. †Colobomatous area separated by a normal retina from the main coloboma.
Journal of AAPOS Volume 6 Number 3 June 2002
Visual function varied among members of the same family with autosomal dominant coloboma. This is despite that all had foveal sparing and no microphthalmos, which bear good visual prognosis.5-7 Gopal et al8 reported an inverse relationship between the VA and the severity of the optic nerve involvement, the latter being correlated with coloboma size. Conversely, Olsen et al found that foveal involvement is the only significant predictor of vision in coloboma patients.6,7 Although our series was small, we also found an association between large coloboma size and optic nerve involvement, but neither necessarily predicted poor acuity. To support this, patients 3 and 4 had, in spite of large asymmetric colobomata with unilateral nerve involvement, near-normal vision in each eye and stereopsis. To the best of our knowledge, a high-grade stereopsis has not been documented in persons with large chorioretinal colobomata. Therefore, we assume that the major factor that affected vision of our patients with foveal sparing was amblyopia. Three patients had anisometropic, strabismic, or combined amblyopia. Although anisometropic amblyopia was described with bilateral coloboma,2,4,6-8 less attention was paid to strabismic amblyopia. Strabismus, usually esotropia, is common with coloboma,4,5,10 but exotropia present in 3 of our patients has been rarely reported.7 Coloboma is often associated with myopia.3,4,8 Our and other recent data suggest that any refractive error can occur with coloboma5,6 and that astigmatism is characteristic. Despite significant refractive errors and asymmetric colobomata in all patients, only 2 patients had large anisometropia causing amblyopia. Therefore, large coloboma should not
Gradstein et al
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falsely condemn a child to poor VA, even if the optic nerve is involved, but the fovea is spared.7 Because coloboma appearance does not predict development of anisometropia or strabismus, a prompt orthoptic evaluation and cycloplegic refraction are warranted in all cases to prevent amblyopia. References 1. Stoll C, Alembik Y, Dott B, Roth MP. Epidemiology of congenital eye malformations in 131,760 consecutive births. Ophthalmic Paediatr Genet 1992;13:179-86. 2. Pagon RA. Ocular coloboma. Surv Ophthalmol 1981;25:223-36. 3. Cross HE. Ocular colobomas. In: Bergma D, editor. Birth defects compendium. 2nd ed. New York: Alan R. Liss; 1979. p. 791. 4. Onwochei BC, Simon JW, Bateman JB, Couture KC, Envar M. Ocular colobomata. Surv Ophthalmol 2000;45:175-94. 5. Hornby SJ, Adolph S, Gilbert CE, Dandona L, Foster A. Visual acuity in children with coloboma. Clinical features and a new phenotypic classification system. Ophthalmology 2000;107:511-20. 6. Olsen TW, Summers CG, Knobloch WH. Predicting visual acuity in children with colobomas involving the optic nerve. J Pediatr Ophthalmol Strabismus 1996;33:47-51. 7. Olsen TW. Visual acuity in children with colobomatous defects. Curr Opin Ophthalmol 1997;8:63-7. 8. Gopal L, Badrinath SS, Kumar KS, Doshi G, Biswas N. Optic disc in fundus coloboma. Ophthalmology 1996;103:2120-7. 9. Gradstein L, Ronen E, Belfair N, Lifshitz T, Biedner B. Visual function, refractive errors and strabismus in patients with familial isolated ocular coloboma. In: Spiritus M, editor. Transactions of the 25th Meeting of the European Strabismilogical Association. Lisse, the Netherlands: Æolus Press Science Publishers; 2000. p. 49-54. 10. Wiggins RE, von Noorden GK, Boniuk M. Optic nerve coloboma with cyst: a case report and review. J Pediatr Ophthalmol Strabismus 1991;28:274-7.
SUBJECTS AND METHODS Six members of a family were affected by an isolated dominant coloboma, the mother (patient 1) and 5 of her 7 children (patients 2-6), totaling 5 females and 1 male, ages 8 to 43 years.9 Patients 1 through 5 underwent complete ophthalmic examinations, cycloplegic refraction, fundus photography, and measurements of axial length and corneal diameter. Patient 6 was adopted into another family and could not be located for a detailed examination. Near stereopsis was assessed by a Titmus Test (Stereo Optical Co, Inc, Chicago, Ill). Axial length was measured by an Ultrasonic Biometer (Humphrey Instruments, Inc, San Leandro, Calif) and corneal diameter by a flexible ruler. Fundus photographs were analyzed with regard to coloboma size, symmetry, and involvement of the optic nerve and fovea. We sought the relationships between
From the Department of Ophthalmology, Soroka Medical Center, The Faculty of Health Sciences, Ben Gurion University of the Negev, Beer-Sheva, Israel. Submitted January 18, 2001. Revisions accepted December 31, 2001. Reprint requests: Libe Gradstein, MD, Department of Ophthalmology, Soroka Medical Center, Beer-Sheva, Israel, 84101. J AAPOS 2002;6:195-7. Copyright © 2002 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/2002/$35.00 ⫹ 0 75/1/122679 doi:10.1067/mpa.2002.122679
Journal of AAPOS
these anatomical features and patients’ visual acuity (VA), ocular alignment, stereopsis, and refractive errors.
RESULTS All the examined patients had bilateral typical iris and chorioretinal colobomata with mild microcornea without microphthalmia (horizontal corneal diameter 8.8-9.8 mm, axial length 21.81-24.80 mm). The Table describes clinical presentation of patients 1 to 5. The defect was asymmetric in all patients. In patients 1 to 4 the sides of larger iris and chorioretinal lesion agreed. In patient 5 iris coloboma was larger in the left eye, but the chorioretinal defect was more extensive in the right eye (Figure). The optic nerve was involved in 4 patients, in each case unilaterally, in the eye with larger chorioretinal defect (Table). The fovea was spared, except splitting by the coloboma (with presence of foveal reflex) in the right eye of patient 3. Best corrected VA ranged from 6/6 to 6/36 (Table). Patients 1, 2, 3, and 5 had unequal acuities in the 2 eyes. In these patients the eye with the larger chorioretinal coloboma had the worse VA, and in 3 of them (patients 1, 3, 5) this was the eye with unilaterally affected optic nerve. In patient 4, the visual acuities were equal despite the larger chorioretinal coloboma with unilateral optic nerve involvement in the left eye. Various refractive errors necessitating optical correction, with astigmatism of at least 1.5 D, were measured in all eyes. Anisometropia of 4 to 8.5 D was detected in patients 1 and 2, both had amblyopia of the eye with the higher refractive error (higher spherical equivalent). Patients 1, 4, and 5 had exotropia, which was surgically corrected in patient 5. Patients 1 and 5 with unilateral exotropia had amblyopia of the exotropic eye. Although in these 2 patients a chorioretinal defect was larger in the exotropic eye, across patients, no association was found between the anatomical features of coloboma and presence of strabismus or anisometropia. Stereopsis of 140" was detected in patients 1 and 3, and of 40" in patient 4. Patients 1, 2, and 5 had amblyopia (a difference of 2 Snellen’s lines or more in VA between the 2 eyes) of anisometropic, strabismic, or combined origin.
DISCUSSION Similarly to other studies,2,5 colobomata were asymmetric in all our patients. Although the sides of larger iris and chorioretinal colobomata usually agreed, patient 5 had a larger chorioretinal defect in the eye with the smaller iris coloboma. This finding has not been previously reported. June 2002
195
196
Journal of AAPOS Volume 6 Number 3 June 2002
Gradstein et al
FIG 1. Iris and chorioretinal colobomata of patient 5. (A), Right eye iris coloboma. Note inferonasal lens opacities found in all eyes, which did not cover visual axis. (B), Larger iris coloboma and more lens opacities in left eye. (C), Right eye chorioretinal coloboma, which involves optic nerve and part of macular area, but not fovea. (D), Smaller chorioretinal defect in left eye limited to inferonasal quadrant, which does not involve optic nerve. Note small satellite lesion under nerve.
TABLE. Clinical findings of patients 1 through 5 Colobomatous involvement Age Pt (years) Gender
Inferonasal iris
Chorioretinal
Optic Nerve
Fovea
BCVA
Stereo acuity
Refraction
Strabismus
1
43
F
OS ⬎ OD
OS ⬎ OD OD: confluent* OS: bridge of normal retina under ON
OD: No OS: Yes
No
OD 6/7.5 OS 6/12
140“
OD ⫹ 5.75–3.00 ⫻ 95 OS ⫺ 2.75–2.75 ⫻ 65
2
15
M
OS ⬎ OD
OS ⬎ OD confluent*
No
No
OD 6/7.5 OS 6/36
None
OD ⫹ 3.00–1.50 ⫻ 5 None OS ⫺ 1.25–1.75 ⫻ 165
3
12
F
OD ⬎ OS
OD⬎OS OD: confluent* OS: with satellite†
OD: Yes OS: No
OD: splits fovea (reflex present) OS: No
OD 6/7.5 OS 6/6
140“
OD plano–3.00 ⫻ 170 OS plano–2.00 ⫻ 10
4
10
F
OS ⬎ OD
OS ⬎ OD OD: with satellite† under ON OS: bridge of normal retina under ON
OD: No OS: Yes
No
OD 6/7.5 OS 6/7.5
40“
OD ⫹ 1.00–2.50 ⫻ 160 D: Intermittent OS ⫹ 0.50–2.50 ⫻ 10 AXT 50⌬
OD ⬎ OS OD: confluent* OS: with satellite† under ON
OD: Yes OS: No
5
8
F
OS ⬎ OD
D: LXT 50⌬ N: Intermittent LXT 25⌬
None
N: Intermittent AXT 30⌬ No
OD 6/21 OS 6/7.5
None
OD ⫹ 3.50–2.50 ⫻ 150 D&N: OS ⫹ 2.50–1.50 ⫻ 160 RXT 60⌬
AXT, Alternating exotropia; BCVA, best corrected visual acuity; D, deviation for distant fixation; F, female; LXT, left exotropia; M, male; N, deviation for near fixation; OD, right eye; ON, optic nerve; OS, left eye; Pt, patient; RXT, right exotropia. *Coloboma without intervening areas of normal retina. †Colobomatous area separated by a normal retina from the main coloboma.
Journal of AAPOS Volume 6 Number 3 June 2002
Visual function varied among members of the same family with autosomal dominant coloboma. This is despite that all had foveal sparing and no microphthalmos, which bear good visual prognosis.5-7 Gopal et al8 reported an inverse relationship between the VA and the severity of the optic nerve involvement, the latter being correlated with coloboma size. Conversely, Olsen et al found that foveal involvement is the only significant predictor of vision in coloboma patients.6,7 Although our series was small, we also found an association between large coloboma size and optic nerve involvement, but neither necessarily predicted poor acuity. To support this, patients 3 and 4 had, in spite of large asymmetric colobomata with unilateral nerve involvement, near-normal vision in each eye and stereopsis. To the best of our knowledge, a high-grade stereopsis has not been documented in persons with large chorioretinal colobomata. Therefore, we assume that the major factor that affected vision of our patients with foveal sparing was amblyopia. Three patients had anisometropic, strabismic, or combined amblyopia. Although anisometropic amblyopia was described with bilateral coloboma,2,4,6-8 less attention was paid to strabismic amblyopia. Strabismus, usually esotropia, is common with coloboma,4,5,10 but exotropia present in 3 of our patients has been rarely reported.7 Coloboma is often associated with myopia.3,4,8 Our and other recent data suggest that any refractive error can occur with coloboma5,6 and that astigmatism is characteristic. Despite significant refractive errors and asymmetric colobomata in all patients, only 2 patients had large anisometropia causing amblyopia. Therefore, large coloboma should not
Gradstein et al
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falsely condemn a child to poor VA, even if the optic nerve is involved, but the fovea is spared.7 Because coloboma appearance does not predict development of anisometropia or strabismus, a prompt orthoptic evaluation and cycloplegic refraction are warranted in all cases to prevent amblyopia. References 1. Stoll C, Alembik Y, Dott B, Roth MP. Epidemiology of congenital eye malformations in 131,760 consecutive births. Ophthalmic Paediatr Genet 1992;13:179-86. 2. Pagon RA. Ocular coloboma. Surv Ophthalmol 1981;25:223-36. 3. Cross HE. Ocular colobomas. In: Bergma D, editor. Birth defects compendium. 2nd ed. New York: Alan R. Liss; 1979. p. 791. 4. Onwochei BC, Simon JW, Bateman JB, Couture KC, Envar M. Ocular colobomata. Surv Ophthalmol 2000;45:175-94. 5. Hornby SJ, Adolph S, Gilbert CE, Dandona L, Foster A. Visual acuity in children with coloboma. Clinical features and a new phenotypic classification system. Ophthalmology 2000;107:511-20. 6. Olsen TW, Summers CG, Knobloch WH. Predicting visual acuity in children with colobomas involving the optic nerve. J Pediatr Ophthalmol Strabismus 1996;33:47-51. 7. Olsen TW. Visual acuity in children with colobomatous defects. Curr Opin Ophthalmol 1997;8:63-7. 8. Gopal L, Badrinath SS, Kumar KS, Doshi G, Biswas N. Optic disc in fundus coloboma. Ophthalmology 1996;103:2120-7. 9. Gradstein L, Ronen E, Belfair N, Lifshitz T, Biedner B. Visual function, refractive errors and strabismus in patients with familial isolated ocular coloboma. In: Spiritus M, editor. Transactions of the 25th Meeting of the European Strabismilogical Association. Lisse, the Netherlands: Æolus Press Science Publishers; 2000. p. 49-54. 10. Wiggins RE, von Noorden GK, Boniuk M. Optic nerve coloboma with cyst: a case report and review. J Pediatr Ophthalmol Strabismus 1991;28:274-7.