Abstract
Purpose :
To characterize the natural history of X-linked retinoschisis (XLRS) and to determine the effect of carbonic anhydrase inhibitors (CAIs) use on function or structure in XLRS.
Methods :
Fifty-six patients 6 years or older (mean = 30.0 [±19.2] years) with a confirmed mutation in the RS1 gene were enrolled in an observational study. At baseline, 6, 12, and 18 months EDTRS best corrected visual acuity (BCVA) was recorded and macular cystic cavity volume (CCV) was calculated by using a custom written algorithm in Matlab to process volume scans from spectral domain optical coherence tomography (SD-OCT). Group A consisted of 18 patient with no use of CAIs prior to or during the study. Group B consisted of 18 patients who previously used CAIs and continued to use CAIs during the study. Group C was composed of 20 patients with no history of CAI use, who were started on these medications at the beginning of the study. Patients in Group C had additional exams at 1 and 3 months after starting topical dorzolamide 2% three times per day.
Results :
The average BCVA and CCV for each group at baseline (BL) and at M6, M12 and M18, and additionally at M1 and M3 for Group C are shown at the Table 1 and 2. There was no significant difference in BCVA and CCV within each group compared to baseline (p>0.05, paired t test, for all comparisons) and between Group C group compared to Groups A and B at each follow up examination (p>0.05, paired t test, for all comparisons). Although there were no statistical differences in mean BCVA between groups at timepoint M12, there was a suggestion of improved visual acuity earlier in the study. At M6, 4 patients in group C demonstrated a letter score increase of 10 or more compared to only 1 patient in Group A, 2 patients in Group B.
Conclusions :
BCVA and SD-OCT findings showed that XLRS is generally stable over an 18 month time period. On average, treatment with topical CAIs was not associated with improvement in visual function or macular cyst volume at one year. However, some individuals demonstrated notable improvement at earlier time points suggesting that efficacy of CAIs is more nuanced.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.