Abstract

ORTEGA DIAZ, Lorelei et al. Changes in the posterior corneal surface one year after surgery. Rev Cubana Oftalmol [online]. 2013, vol.26, n.2, pp. 236-244. ISSN 0864-2176.

Objective: to describe the changes of the posterior corneal curvature observed in patients who underwent laser-assisted refractive surgery at ¨Ramón Pando Ferrer¨ Cuban Institute of Ophthalmology from January through December 2011. Methods: a prospective, longitudinal and descriptive study of a sample of 31 patients (59 eyes) selected from a universe of 257 patients (504 eyes), who underwent laser-assisted refractive surgery. The analyzed variables were age, sex, spherical equivalent, pachymetry before surgery, ablation magnitude, residual stroma and difference in posterior corneal elevation. The latter was obtained from the Galilei´s tomograph difference map with measurements before surgery and one month, three months, six months and a year after surgery. Stepwise multiple regression analysis allowed evaluating such changes with pachymetry, ablation microns, residual stroma and intraocular pressure. Results: spherical equivalent, pachymetry, ablation microns, residual stroma and intraocular pressure were within the set safety criteria. The average difference of the posterior corneal elevation was 15,62 µm at one month, 15,62 µm three months, 7,68 µm six months and 3,22 µm one year after the surgery, with significant reduction as time goes by (p=0.000). Preoperative pachymetry, residual stroma and intraocular pressure were found to be related. Conclusions: laser-assisted refractive surgery causes an early increase of the posterior corneal elevation, with progressive reduction in time. The most influential factors were residual stroma, preoperative pachymetry and intraocular pressure.

Keywords : LASIK; LASEK; posterior corneal elevation; pachymetry; residual stroma; intraocular pressure.

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