Abstract
Purpose :
Progressive decline in visual field (VF) that leads to blindness is a main characteristic of retinitis pigmentosa (RP). We performed a retrospective study to determine the rate of VF progression in patients with RP as it relates to different target sizes and inheritance patterns.
Methods :
More than 1300 medical records were reviewed from two ocular genetics databases of patients seen in the eye clinic for the past 40+ years. Patients with RP were included who had at least 2 Goldmann visual field tests. For these subjects, data was collected for medical history, age at onset, genotype, inheritance pattern, best corrected visual acuity (BCVA), and VF (V4e, III4e, and I4e). Photoshop was used to measure visual field area. Data were analyzed using descriptive statistics, Pearson correlation, ANOVA, and survival analysis.
Results :
Data from 50 subjects with RP were available for analysis with a total of 266 VF tests. The median follow-up time was 10 years (range: 2-29 years). The median number of the visual field tests per subject was 4 (range: 2-18 years). The inheritance patterns included autosomal dominant (AD, n=4), autosomal recessive (AR, n=32), and X-linked (n=14). There was significant intern-ocular correlation in both BCVA (R2=0.641, P<0.001) and VF (R2=0.802, P<0.001). The annual rate of decline of VF area for V4e, III4e, and I4e were 7.6%, 13.4%, and 12.7%, respectively. A significant difference was found between V4e and I4e (p=0.039). Comparison among inheritance patterns revealed a significant difference for the target V4e, with AR showing the fast rate of decline (10.0%) compared to AD (1.5%, p=0.047) and X-linked (3.8%, p=0.037). While, no significant difference was found among inheritance patterns for the targets III4e and I4e. Survival analysis indicated that the median age of survival was 37 years to meet the VF standard for driving, 51 years to be categorized as legally blind defined by VF, and 62 years to be defined as legally blind by BCVA.
Conclusions :
Both eyes degenerate symmetrically in terms of VA and VF in patients with RP. VF progression rate varies among target sizes and inheritance patterns. VF declines faster compared to visual acuity. These results can be useful for counselling patients with RP and various inheritance patterns as to their potential rate of visual field loss.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.