Retrospective, longitudinal, and cross sectional study of visual acuity impairment in choroideraemia.

Background/aims: Few studies have reported on the change in visual acuity (VA) in patients with choroideraemia. In order to determine the degree and rate of VA impairment associated with this disease, the central VA was analysed in a large group of patients with choroideraemia.
Methods: The authors completed a retrospective, cross sectional review of 115 patients with choroideraemia from three tertiary care centres. A longitudinal analysis was performed on 45 of these patients who met the inclusion criteria of at least three visits over a minimum period of 4.5 years. Multiple linear regression analysis was used to explore the 5 year rate of VA change while controlling for initial VA and initial age. Multiple logistic regression was also used to investigate VA impairment.
Results: In the cross sectional group (n = 115), 84% (87/103) of patients under the age of 60 had a VA of 20/40 or better while 33% (4/12) of patients 60 years of age or older had a VA of 20/200 or worse at their most recent visit. The majority of the patients (93%) in the longitudinal subgroup of 45 patients had a VA of 20/30 or better at their initial visit. The mean 5 year rate of VA change was 0.09 logMAR equivalent (approximately one line on the Lighthouse chart).
Conclusion: In this cohort of patients with choroideraemia, there was typically a slow rate of VA loss and the prognosis for central VA retention was, as a group, favourable until the seventh decade.