Visual morbidity in thirty-four families with Schnyder crystalline corneal dystrophy (an American Ophthalmological Society thesis).

Abstract

PURPOSE: To assess the findings, visual morbidity, and surgical intervention in Schnyder crystalline corneal dystrophy (SCCD). METHODS: Retrospective case series of 115 affected individuals from 34 SCCD families identified since 1989. Age, uncorrected visual acuity, best-corrected visual acuity (BCVA), corneal findings, and ocular surgery were recorded. Prospective phone, e-mail, or written contact provided updated information. Patients were divided into 3 age categories for statistical analysis: less than 26 years of age, 26 to 39 years of age, and 40 years of age and older. RESULTS: Mean age on initial examination was 38.8 +/- 20.4 (range, 2-81) with follow-up of 55 of 79 (70%) of American patients. While there were no statistical significant correlations between logMAR visual acuity and age (logMAR BCVA =.033 + .002 x age; R =.21), the linear regression showed the trend of worse visual acuity with age. BCVA at > or =40 years was decreased compared to <40 (P < .0001), although mean BCVA was > 20/30 in both groups. Twenty-nine of 115 patients had corneal surgery with 5 phototherapeutic keratectomy (3 patients), and 39 penetrating keratoplasty (PKP) (27 patients). PKP was reported in 20 of 37 (54%) patients > or =50 years and 10 of 13 (77%) of patients > or =70. BCVA 1 year prior to PKP in 15 eyes (9 patients) ranged from 20/25 to 20/400 including 7 eyes with other ocular pathology. BCVA in the remaining 8 eyes was 20/25 to 20/70 with 3 of these 4 patients reporting preoperative glare. Chart and phone survey suggested increasing difficulty with photopic vision with aging. CONCLUSION: Although excellent scotopic vision continues until middle age in SCCD, most patients had PKP by the 7th decade. SCCD causes progressive corneal opacification, which may result in glare and disproportionate loss of photopic vision.