Effect of Computer Tasks in Straight Gaze on Corneal Topographic Indices.

Purpose: To investigate the effect of the near visual task of movie-watching in the straight gaze position on corneal topographic parameters.

Methods: Thirty myopic young adults with an average age of 25.10 $\pm$ 4.13 years were recruited for the study. The designed near visual task consisted of watching a movie in the straight gaze position at a distance of 40 cm for 30 minutes. Corneal topography was performed using Oculus Keratograph 4 (OCULUS, Wetzlar, Germany) before and immediately after watching the movie, as well as at 10, 20, and 30 minutes intervals after completing this near visual task. Zernike coefficients, asphericity indices, refractive parameters, and diagnostic indices of keratoconus were recorded for statistical analysis.

Results: Movie-watching at a close distance solely using the straight gaze position had no effect on Zernike coefficients (P $>$ 0.130). Also, watching the movie had no effect on other corneal topography parameters including irregularities (P = 0.208), spherical eccentricity (P = 0.270), maximum decentration (P = 0.553), axis of maximum decentration (P = 0.186), peripheral astigmatism (P = 0.179), and average asphericity of the quadrants at 10 to 30º (P $>$ 0.163).

Conclusion: The results of the present study showed that watching movies in the straight gaze position had no effect on corneal topographic parameters and did not cause errors in corneal topographic measurements.