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Jason Charng, Tina Lamey, Jen Thompson, Terri Mclaren, Mary Attia, John De Roach, David A Mackey, Fred Kuanfu Chen; Cross-sectional and longitudinal analyses of microperimetry in USH2A-related retinitis pigmentosa. Invest. Ophthalmol. Vis. Sci. 2020;61(7):3384.
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© ARVO (1962-2015); The Authors (2016-present)
Microperimetry is a key outcome measure for treatment trials in rod-cone dystrophy. Mesopic Macular Integrity Assessment (MAIA; CenterVue, Padova, Italy) microperimetry was analyzed in an Australian cohort with biallelic USH2A mutations.
This is a retrospective analysis of MAIA data from a single center. DNA was analysed by targeted next-generation sequencing of ocular genes. Whenever possible, two MAIA patterns (i.e. small grid, large grid) were performed in both eyes at the same visit. Small grid consisted of 37 loci arranged in a radial pattern sampling retinal locations at 0° and 1°, 2° and 3° eccentricity from the fovea. Large grid contained 68 test loci arranged in a square array centered on the fovea. Adjacent test loci were separated by 2°, at 1°, 3°, 5°, 7° and 9° from the vertical or horizontal meridian. Cross-sectional data was analyzed at patients’ first visits. A subset with follow-up was analyzed using right eye data only.
In 19 patients, biallelic mutation of USH2A was identified and considered disease-causing. Large and small grid data were available in 14 (74%, mean age 34y, age range 14–65y) and 11 (58%, 38y, 16–65y) patients, respectively. Macular sensitivity (mean±std) measured with the large and small grids were 10.5±7.3 and 23.4±6.6 dB, respectively. The mean number of dense scotoma loci was 22±20 (large) and 0.8±2.7 (small). The mean (95%CI) inter-ocular difference (right – left) in sensitivity by eye was +0.3 (-2.4 to +2.9, large) and +0.2 (-3.7 to +4.2, small) dB. Mean (95%CI) pointwise inter-ocular symmetry was 0.3 (-10.6 to +10.2, large) and 0.2 (-9.1 to +9.5, small) dB. Follow-up data was available in 12 (large) and 10 (small) right eyes. Follow-up period was 2.7±1.8 (large) and 2.3±1.2 (small) years. Mean (±std) rate of change was -0.9±1.3 (large) and -1.0±2.5 (small) dB/year. Scotoma loci increased by a mean of 2.9±5.0 (large) and 0.6±1.8 (small) loci/year.
Microperimetry was feasible in 75% of USH2A-related retinitis pigmentosa patients. The large grid had lower mean sensitivity and a greater number of scotoma loci than the small grid. Although mean inter-ocular difference was negligible, the variations were large. Mean sensitivity declined by a similar magnitude between the two grids, but the large grid had a greater annual gain in scotoma loci.
This is a 2020 ARVO Annual Meeting abstract.
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