Characterizing the refractive error during the first 2 decades of life in patients with congenital stationary night blindness

Abstract

Purpose : Congenital stationary night blindness (CSNB) is known to be associated with high myopia. However, there is only limited information on the natural history of refractive error and the variability by causal gene in patients with CSNB. We performed a multi-center, retrospective study to better characterize refractive error in CSNB.

Methods : In this multinational study 138 patients with a clinical and molecular diagnosis of CSNB age 1-20 years were included from 8 sites We conducted a retrospective longitudinal chart review including data on age, refractive error, and genotype. Refractive error was defined as spherical equivalent of refraction (SER). Inclusion criteria were at least 2 longitudinal SER measurements and a known genetic variant. Unpaired t-tests were used to evaluate the differences in SER and age of measurement between genes.

Results : The mean ± SD age in years at the youngest measurement was 6.70 ± 4.18, 5.03 ± 2.87, 3.88 ± 3.18, 3.80 ± 3.76, and 4.40 ± 2.80 for CACNA1F, NYX, TRPM1, GRM6, and GPR179 respectively. The mean ± SD age in years at the oldest measurement was 12.06 ± 4.79, 8.85 ± 8.62, 9.75 ± 4.84, 8.20 ± 5.11, and 8.80 ± 3.71 for CACNA1F, NYX, TRPM1, GRM6, and GPR179 respectively. The mean ± SD SER for the youngest measurement was -3.50D ± 5.01D, -6.51D ± 3.44D, -5.44D ± 3.14D, -5.28D ± 5.81D, -7.40D ± 2.26D for CACNA1F, NYX, TRPM1, GRM6, and GPR179 respectively. The mean ± SD SER for the oldest measurement was -4.79D ± 5.89D, -6.51D ± 3.44D, -7.54D ± 4.43D, -6.60D ± 6.54D, and -9.00D ± 3.56D for CACNA1F, NYX, TRPM1, GRM6, and GPR179 respectively. The two X-linked genes were CACNA1F and NYX. Age at the youngest measurement was not significantly different for CACNA1F vs NYX (p=0.120). Age at the oldest measurement was significantly older for CACNA1F vs NYX (p=0.032). The SER for NYX was significantly more myopic than CACNA1F (p=0.017, p=0.009) for the youngest and oldest measurements respectively.

Conclusions : Average age at the first measurement was not significantly different whereas the average age at the last visit was higher in CACNA1F than NYX. Despite that myopia increased as age increased, NYX had significantly higher myopia than CACNA1F at both the first and last measurement.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.