WIDE-SPREAD MYELINATED NERVE-FIBERS OF THE OPTIC DISC - DO THEY INFLUENCE THE DEVELOPMENT OF MYOPIA

Purpose: To find correlations between the extent of myelinated nerve f ibers with refraction anomalies. Method: Searching for myelinated nerv e fibers in the slide collection of the University Eye Hospital Freibu rg we found 13 patients. We distinguished between eyes with wide-sprea d myelinated nerve fibers located on and around the optic disc which e xtended to the midperiphery of the retina (6 patients; Group A) and ey es with circumscribed myelinated nerve fibers, localized merely around the optic disc (7 patients, Group B). In Group A myelinated nerve fib ers spared the macula area, but were localized very close to the macul a. Color fundus photographs were taken by the Zeiss Fundus camera SK50 (30 degrees and 50 degrees picture size) and by the Olympus Fundus ca mera GRC-W (same picture size). Results: The myelinated nerve fibers w ere found to be unilateral in all 13 patients. In all 6 patients of Gr oup A, a strabismus was present. The affected eye had a severe amblyop ia and a unilateral myopia (- 5.75 to - 25.0 D.). The nonaffected fell ow eye showed a normal visual acuity with no or only a slight refracti ve error. In the 7 patients of the Group B, no strabismus was present and a normal or a slightly decreased visual acuity of the affected eye was found. No distinct refractive error was present in the affected a nd non-affected eyes of this group. Conclusions: Myopia only occurred in eyes with wide-spread myelinated nerve fibers but not in eyes with circumscribed myelinated nerve fibers. We assume that myelinated nerve fibers, if wide-spread, cause myopia.