[Effect of corneal refractive surgery on optical coherence tomography measurements]

The effect of significant changes in corneal power after refractive surgery on the parameters of optical coherence tomography (OCT) has not been sufficiently studied.

To study effects of corneal refractive surgery on optical coherence tomography (OCT) measurements in patients with moderate and high myopia.

OCT was performed in 62 patients (62 eyes) with myopia over 4 D before and one month after LASIK. The changes in 14 parameters of the thickness of the retina, ganglion cell-inner plexiform layer (GCIPL) and peripapillary retinal nerve fiber layer (pRNFL) were analyzed.

The mean refractive effect was 7.07±2.02 D (4.0 to 11.75 D). Postoperative changes in the parameters analyzed were insignificant, averaging not more than 1.3% of the baseline value with the exception of pRNFL thickness in the temporal quadrant (2.2%). Only six of the 14 parameters were statistically significant - retinal thickness in the central subfield and the inner nasal quadrant, average and minimum thickness of GCIPL, and pRNFL thickness (mean and in the temporal quadrant). Individual changes of the parameters in most patients did not exceed the error of method.

In patients with moderate to high myopia, LASIK operation has only a slight effect on the OCT parameters of the retina and pRNFL. Only in patients with very high myopia, the decrease over 10 D in corneal refractive power creates an optical effect of increasing the average thickness of pRNFL and GCIPL by 2-3 μm. This should be taken into account when examining such patients for glaucoma.