Correlation of optic-disc area and refractive error
Eileen Faye S. Enrique, MD, Mario M. Yatco, MD, Noel M. Castillo, MD
Objective
This study measured the optic-disc area using optical coherence tomography (OCT) and correlated it with the type of refractive error.
Methods
A cross-sectional study was conducted involving 73 healthy Filipinos aged 20 to 60 years. All underwent a full ophthalmologic examination including visual acuity, automated refraction, Goldmann applanation tonometry, and dilatedfundus examination. Fast optic-nerve-head imaging was performed with 6 radial linear scans centered on the optic-nerve head. Data were tabulated and the association between optic-disc measurements
and refractive error was analyzed using analysis of variance and linear regression.
Results
A total of 142 eyes of 73 patients were included, of which 39 (27.5%) were classified as emmetropia or hyperopia, 47 (33%) as low myopia, 37 (26.2%) as moderate myopia, and 19 (13.4%) as high myopia. The mean refractive error was –9.2 ± 2.98D for those with high myopia, –4.7 ± 0.74D for moderate myopia, –1.7 ± 0.78D for low myopia, and 1.1 ± 2.55D for emmetropia and hyperopia. The mean optic-disc area for all groups was 2.70 ± 0.59 mm2 (range, 1.6 to 4.7 mm2 ); the mean optic-disc area was similar for high myopia (2.7 ± 0.57 mm2 ) and low myopia (2.7 ± 0.52 mm2 ). There was no significant difference in the optic-disc area of the different types of refractive errors (p = 0.30).
Conclusion
This study showed that the optic-disc area is statistically independent of the refractive error.
Keywords: Optic-disc area, Emmetropia, Hyperopia, Myopia, Optical coherence
tomography