Nearwork-induced transient myopia and accommodation function before and after laser-assisted in situ keratomileusis surgery

Purpose: To assess the change in Near Induced Transient Myopia (NITM) and other accommodation parameters, before and after undergoing LASIK surgery for myopia correction. Methods: Twenty-nine myopic subjects were recruited from a tertiary eye hospital in India. Age range was 21 to 35 years with an average age of 26.1 +/- 3.5 years. Mean spherical equivalent was -3.86 D +/- 1.50 D presurgery. NITM, lag of accommodation, near point of convergence (NPC), accommodative amplitude (AA), and binocular near accommodative facility (AF) were measured. All data were collected 21 days prior to and 30 days after LASIK surgery. Results: NITM, lag of accommodation and amplitude of accommodation were significantly lower (NITM -0.05 +/- 0.15, Lag 0.38 +/- 0.38, AA 10.27 +/- 2.24) after surgery when compared to before (NITM 0.26 +/- 0.12, Lag 0.77 +/- 0.51, AA 12.18 +/- 2.02; P < 0.001). Accommodative facility increased and near point of convergence was significantly more distal following surgery (AF 10.70 +/- 2.29, NPC 7.96 +/- 1.63) when compared to prior (AF 8.65 +/- 2.74, NPC 5.62 +/- 1.71; P < 0.001). Conclusion: Significant changes in NITM and accommodation function should be expected in the short term following LASIK surgery. This study supports the importance of evaluating accommodative parameters and patient counselling prior to and following refractive surgery.