Visual acuity loss during one year in Stargardt Disease: ProgStar Prospective Study

Abstract

Purpose : Prior studies estimating the rate of VA loss in Stargardt patients were all based on retrospective chart reviews where data quality may be limited due to inconsistency in testing procedures. Using data from prospective follow-up of participants of the ProgStar study, we estimated VA loss during one year and determined the associations with demographic and clinical factors.

Methods : 259 molecularly confirmed Stargardt patients were enrolled from nine sites, and were followed at 6 and 12 months. Monocular best corrected VA (BCVA) was measured using an ETDRS chart following a standardized protocol. Trained site coordinators double entered data into a central database (REDCap). We used linear models with generalized estimating equations to compare baseline BCVA (in LogMAR scale) by participant characteristics, and using available longitudinal data up to 12 months, we used linear mixed effects model to estimate the VA loss rate.

Results : The median age was 31 (range 7-69) years, and 54% were female. Median age of symptom onset was 19 (range 4-64) years, and median duration since symptom onset was 9 (range 0-55) years. There were 35 (14%) former and 29 (11%) current smokers. The mean baseline BCVA of the 489 study eyes was 0.78 LogMAR (SD=0.32). RPE Pigmentation was associated with 0.1 LogMAR worse VA (p=0.006), and having flecks outside the arcades was associated with 0.18 LogMAR worse VA (p<.0001). VA of current smoker was 0.10 LogMAR worse than never smokers (p=0.09). Juvenile symptom onset (onset age≤18 years) was associated with 0.22 LogMAR worse VA (p<.0001), and longer duration since symptom onset was associated with worse VA (p<.0001). During 12 months follow-up, there was no significant change in VA overall, but VA declined significantly at a rate of 0.04 LogMAR per year in eyes with initial VA better than 20/25 (p=0.03). VA loss ≥ 1line (i.e. ≥0.1 LogMAR) from baseline to month 12 occurred in 12% eyes. The risk of such loss was highest (19%) in eyes with initial VA better than 20/25 and in eyes with initial VA between 20/25 to 20/70. The risk of VA loss was not associated with the presence of flecks outside the arcades, RPE pigmentation, smoking, younger age of symptom onset, or symptom duration.

Conclusions : Overall, one year VA change was minimal, but 12% of eyes lost at least one line of VA. Eyes with initial good VA had significant VA loss over the year.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.