The Effect of Soft Contact Lenses on Optic Nerve Head Measurements Using Optical Coherence Tomography

Purpose: To evaluate the effect of soft contact lens induced myopia and hyperopia on optic nerve head measurements of normal eyes using spectral domain optical coherence tomography (SD-OCT). Methods:  This cross sectional study was performed on 114 emmetropic eyes of 57 participants. Each participant underwent a complete ophthalmic examination including determination of best-corrected visual acuity, intraocular pressure, dry and cycloplegic refraction as well as axial length measurement. SD-OCT measurement was performed in all ayes while different levels of refraction strength were induced by wearing soft contact lenses of five different diopters (- 10.00, - 5.00, Plano, + 5.00, + 10.00). Results:  The mean measured thicknesses of retinal nerve fiber layer were 123.29 ± 10.56 micrometer, 123.17 ± 11.61 micrometer, 122.77 ± 11.61 micrometer, 123.37 ± 11.15 micrometer and 123.42 ± 11.45 micrometer in contact lens induced high myopia, moderate myopia, emmetropic, moderate hyperopia, and high hyperopia groups, respectively (P = 0.721). Also, corresponding evaluations for mean rim area (P = 0.781), mean optic disc area (P = 0.601), mean cup area (P = 0.53), and mean cup to disc area ratio (P = 0.414) showed no statistically significant difference. Conclusion: Our findings indicate that refractive error variation at the corneal plane caused by contact lens wear has no significant effect on thickness of retinal nerve fiber layer, disc area, cup area, rim area and mean cup to disc area ratio measured by SD-OCT.Keywords: Contact Lenses; Hyperopia; Myopia; Tomography, Optical Coherence; Optic Nerv