Abstract
Purpose :
X-linked retinoschisis (XLRS) is a leading cause of hereditary juvenile macular degeneration in males and genetic therapies are becoming a real possibility. We report on detailed functional and morphological assessment of macular integrity in XLRS male patients and female carriers.
Methods :
Eight male patients and five female carriers from six families with genetically confirmed mutations in RS1 gene were included. All participants underwent detailed ophthalmological examination and psychophysical tests including best-corrected visual acuity (BCVA) and color vision tested with Cambridge Color Test (CCT), fixation stability measurements and microperimetry (MP). Additionally, optical coherence tomography (SD-OCT) was performed.
Results :
In the eight male patients (mean age 18.6±8.1 years, range 5 to 28 years), BCVA was reduced to 0.5±0.24 logMAR, showing symmetrical results between the eyes (0.51±0.27 for the right and 0.48±0.22 for the left eye). Color discrimination showed elevated thresholds ((in u’v’*10-4) for all axes with the tritan axis being the most affected (mean thresholds for protan 178±108, deutan 251±150 and tritan 665±327, respectively). Macular sensitivity was significantly lower (21.5±2.8 dB) than in controls (29.7±0,9 dB). The correlation between BCVA and central retinal thickness (CRT) was strong (rS= -0.8, p=0.0005), while correlations between central BCVA and color thresholds in general were low (rS= -0.33, p=0.29 for protan thresholds). Interestingly, deutan thresholds showed a strong correlation with average MP macular sensitivity (rS= -0.7, p=0.001) and a good correlation with fixation stability described as BCEA95% (rS=0.55) and outer segment thickness (OST) measured in SD-OCT (rS= -0.53). Female carriers (mean age 47.8±7 years, age range 39 to 55 years) showed values within normal limits in every psychophysical test and structural measurement.
Conclusions :
Besides their decreased BCVA, XLRS patients also show diminished color vision with more affected tritan thresholds, lower macular sensitivity and fixational disorders. According to our findings, color discrimination thresholds – especially deutan thresholds, fixation stability and measurements of the OST might be useful outcome measurements of macular integrity in XLRS-related clinical trials, where refined outcome measures to monitor disease progression or therapeutic interventions are needed.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.