Characteristics of myelinated retinal nerve fibres in associated straatsma syndrome

To study cases diagnosed of myelinated retinal nerve fibres (MRNF) continuous with the optic disc and describe the plausible pathogenic mechanism for the ocular features in Straatsma syndrome. This retrospective observational study includes clinically diagnosed MRNF cases. MRNF, myopia, and amblyopia defined Straatsma syndrome. MRNF were classified into three types based on location: type 1 in the superior retina, type 2 in the superior and inferior retina, and type 3 in the inferior retina. MRNF size was measured on Optomap (Optos, Daytona, UK) images and posterior staphyloma location was noted. Demographics and best-corrected refractive error in logMAR units was recorded. Descriptive statistics and Spearman's corelation test were used to analyse MRNF size's relationship to refractive error and logMAR visual acuity. The study included a total of 19 MRNF eyes from 18 patients. Seventeen (89%) eyes had Straatsma syndrome. Median age was 23.50 [range: 4-75] years. One (6%) patient exhibited bilateral presentation. The median logMAR visual acuity was 0.4 log units (interquartile range: 0.18-1.20) and mean refractive error was -7.21 ± 5.32. Type 2 MRNF ( = 14,74%) was the commonest. Average MRNF size was 34.37 ± 40.73 sq.mm. Posterior staphyloma was noted in 17 eyes, all in close MRNF association. Significant positive corelation was noted between logMAR visual acuity and MRNF size ( = 0.5, = 0.028). Large size MRNF corelated with poor visual acuity in the study. The paper explains the possible pathogenetic mechanisms for the ocular findings seen in MRNF.