Longterm findings in peripapillary crescent formation in eyes with mild or moderate myopia

Purpose: To describe early changes of optic disc deviation and peripapillary crescent formation in eyes with mild or moderate myopia. Methods: We carried out a retrospective review of medical records and fundus photographs. We evaluated serial fundus photographs taken in 10 patients with mild or moderate myopia. We observed longterm changes in optic disc areas by creating video files using these photographs and Photoshop (R) and Windows Movie Maker (R) software. The distance between the fovea and the temporal edge of the optic disc was measured in each photograph and any gradual changes in distance between these in the same patient were regarded as representative of optic disc deviation. Correlations between optic disc deviation (0-34.5% disc diameter) and either progression of myopia (- 0.75 D to 6.25 D) or length of follow-up (21-98 months) were statistically examined. Results: On video files, the optic disc appeared to gradually deviate towards the nasal side and the myopic crescent developed gradually in the temporal side of the optic disc in most myopic patients. A significant correlation was found between optic disc deviation and progression of myopia (r(2) = 0.61, p < 0.0001), but no correlation was detected between disc deviation and follow-up period (r(2) = 0.055, p = 0.33). As optic disc deviation progressed, the peripapillary crescent became larger. Conclusions: The optic disc appears to deviate mostly nasally as myopia progresses and the peripapillary crescent forms as a result of optic disc deviation in eyes with mild or moderate myopia.