Correlation of optic-disc area and refractive error

Eileen Faye S.  Enrique, MD; Mario M. Yatco, MD; Noel M. Castillo, MD

Authors

Eileen Faye S. Enrique, MD Department of Ophthalmology University of Santo Tomas Hospital Manila, Philippines Author
Mario M. Yatco, MD Department of Ophthalmology University of Santo Tomas Hospital Manila, Philippines Author
Noel M. Castillo, MD Department of Ophthalmology University of Santo Tomas Hospital Manila, Philippines Author

Keywords:

Optic-disc area, Emmetropia, Hyperopia, Myopia, Optical coherence tomography

Abstract

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 dilated-fundus 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.