To describe the clinical course of congenital aniridia and to evaluate prognostic factors for visual outcome after long-term follow-up.
The medical records of 120 eyes from 60 patients with congenital aniridia were retrospectively reviewed. The prevalence and clinical course of ophthalmic characteristics, systemic disease, refractive errors, and visual acuity were assessed. Prognostic factors for final visual outcomes were analyzed.
Aniridic keratopathy developed in 82 (69%) of 119 eyes. Macular hypoplasia was observed in 70 eyes of 35 patients (91%). Cataract was observed in 63 of 120 eyes (53%). Nystagmus was present in 41 patients (68% of 60 patients) at the initial visit but decreased in five patients (8% of 60 patients). Ocular hypertension was detected in 19 eyes (20% of 93 eyes), six (32% of 19 eyes) of which developed secondarily after cataract surgery. The mean changes in spherical equivalent and astigmatism during the follow-up period were -1.10 and 1.53 diopter, respectively. The mean final visual acuity was 1.028 logarithm of minimal angle of resolution. Nystagmus and ocular hypertension were identified as prognostic factors for poor visual outcome.
Identification of nystagmus and ocular hypertension was important to predict final visual outcome. Based on the high rate of secondary ocular hypertension after cataract surgery, careful management is needed.
Congenital aniridia is a rare congenital disorder characterized by varying degrees of hypoplasia of the iris. It develops due to a mutation in the
This study was approved by the Seoul National University Hospital Institutional Review Board and was conducted in accordance with the Declaration of Helsinki ethical principles for medical research. Detailed medical records from all patients who were diagnosed with aniridia at Seoul National University Children's Hospital between 1990 and 2010 were retrospectively reviewed. All patients were diagnosed and examined by the same ophthalmologist (YSY) and were referred to pediatricians for systemic evaluations.
The initial and final statuses of the cornea, lens, fundus, intraocular pressure (IOP), nystagmus, strabismus, and refractive errors as determined using cycloplegic refraction were compared. Fundus examination was performed with an indirect ophthalmoscope at the initial visit, and ultrasonography was used in cases in which the fundus was not visible. Macular hypoplasia was diagnosed when there was no macular depression or macular reflex during fundus examination. IOP was recorded with the TonoPen (Mentor, Norwell, MA, USA), and ocular hypertension was diagnosed if the IOP was continuously elevated over 21 mmHg and in patients for whom IOP-lowering eye drops had been prescribed. Cycloplegic refraction was performed via manual retinoscopy 30 minutes after a series of three drops of 1% cyclopentolate, which were administered five minutes apart. When lens opacity was considered prohibitive of visual improvement, cataracts were removed. Posterior capsulotomy and anterior vitrectomy were performed in every surgery. Intraocular lenses were inserted considering ocular size and patient age.
To identify changes in refractive errors, we analyzed refractive errors in phakic patients only, comparing the results to those who were initially assessed at age 5 years or younger and who were followed for at least three years. We compared the initial and final refractive errors in these patients. For the evaluation of long-term visual outcomes, we identified the patients who underwent follow-up for five or more years after the initial assessment. The final visual acuities were measured using the Snellen visual acuity chart. Various ocular and systemic status characteristics were analyzed in order to identify prognostic factors for final visual outcome. We used only the right eyes of patients in order to exclude inter-eye correlation during evaluation of refractive error changes and prognostic factors for final visual outcome.
We used SPSS ver. 17.0 (SPSS Inc., Chicago, IL, USA) for all statistical analyses. All of the tests were two-tailed, and significance was set at 0.05. Refractive error changes measured during the follow-up period were compared with paired
In total, 120 eyes from 60 patients were enrolled in this study. Of the study population, 19 patients (32%) had family histories of aniridia, and 36 patients (60%) did not. The remaining five patients (8%) had no information regarding a family history of aniridia. The mean patient age at the initial visit was 23 months, and 85% of the patients were aged <3 years. Detailed patient demographics are summarized in
Six eyes from three patients (5%) had other congenital ophthalmic anomalies: Peters' anomaly (four eyes, two patients) and microphthalmia with sclerocornea (two eyes, one patient). Corneal opacities were documented in 82 eyes from 41 patients (69%) during the follow-up period. Cataracts were observed in 63 eyes total (53%); 35 eyes (56% of cataracts) had cataracts at the initial visit, and 28 eyes (44% of cataracts) developed cataracts during the follow-up period (
Refractive error was assessed in 27 eyes from 27 patients who were initially assessed at age five years or younger and who were followed for at least three years. The mean age of initial and final cycloplegic refraction was 37 and 141 months of age, respectively. The mean change in spherical equivalent over the course of the follow-up period was -1.10 diopter (D), and the mean change in astigmatism was 1.53 D. Overall, 18 eyes (67%) experienced myopic shifts, and nine eyes (33%) experienced hyperopic shifts (
Visual outcomes were assessed in 41 eyes from 41 patients. The average final visual acuity was 1.028 ± 0.611 logMAR (20 / 213). The mean age at which final visual acuity was measured was 158 months (range, 60 to 270 months), and the mean follow-up period before final visual acuity assessment was 143 months (range, 60 to 267 months). The distribution of final visual acuities is presented in
Four patients (7%) who participated in this study developed Wilms' tumors. On average, these patients were diagnosed at 38.3 months of age (range, 12 to 48 months). Among those four patients with Wilms' tumors, three were diagnosed with Wilms' tumors, aniridia, genitourinary abnormalities, and mental retardation (WAGR) syndrome. Three patients (5%) had Gillespie syndrome (aniridia, cerebellar ataxia, and mental retardation). Other associated systemic anomalies included cardiopulmonary anomalies (four patients), urogenital anomalies (two patients), a gastrointestinal anomaly (one patient), and a central nervous system anomaly (one patient). Three patients had multiple systemic anomalies.
Aniridia is a rare congenital anomaly in which iris abnormalities are the prominent feature. However, since other ocular structures are also affected, visual outcomes are typically poor. Among the systemic anomalies that occur in conjunction with aniridia, some appear at birth, while some develop during early childhood [
Cataracts occur in 50% to 85% of aniridia patients and are known to develop during the first two decades of life [
Macular hypoplasia is a common condition in aniridia [
The cause of nystagmus in aniridia is not well established. However, it is thought to be either the result of poor development of central vision due to foveal hypoplasia [
Glaucoma in congenital aniridia is known to develop in 6 to 75% of patients during the adolescent or early adolescent years due to progressive change in the structure of the angle [
Among the various factors, nystagmus and ocular hypertension had statistically significant correlations with final visual outcome. In patients that developed ocular hypertension or had nystagmus at the initial examination or the follow-up examination, the final visual outcome was poor. Therefore, nystagmus may be either a cause or a result of a poor visual outcome; however, it may still be an indicator of poor visual outcome. In addition, ocular hypertension was identified as another significant risk factor for poor visual outcome. The mean final visual acuities of the eyes with and without ocular hypertension were 1.645 ± 0.691 logMAR (20 / 880) and 0.890 ± 0.442 logMAR (20 / 155), respectively (independent sample
This study has several limitations. Due to the retrospective design of this study, although keratopathy is a well known cause of visual disturbance in aniridia [
Nevertheless, this study has several valuable contributions. To the best of our knowledge, no prior studies have described the general clinical course of congenital aniridia over a long-term follow-up period with a large number of patients, particularly younger patients. Therefore, we were able describe the changes in various ophthalmic features in aniridia that occurred during the developmental period. In addition, this is the first study that analyzed the prognostic factors for visual outcome. Nystagmus and ocular hypertension were identified as poor prognostic factors for final visual outcome. If cataract surgery was performed, IOP monitoring is important since there was a high rate of secondary ocular hypertension after cataract operations.
No potential conflict of interest relevant to this article was reported.
Changes in spherical equivalent (A) and astigmatism (B) between the initial and final exams in congenital aniridia.
Distribution of final visual acuity in congenital aniridia.
Demographic characteristics of patients with congenital aniridia
Dominant types of lens opacities in congenital aniridia, and the chronology of their appearance during the follow-up period
Values are presented as number (%).
IOL = intraocular lens.
Correlations between clinical characteristics and final visual outcome (logarithm of minimal angle of resolution)
*Statistical significance.