Impact of Superficial Keratectomy on Corneal Topography, Aberration, and Densitometry in Salzmann Nodular Degeneration.

Objectives: The aim of this study was to evaluate changes in corneal topography, wavefront aberrations, and densitometry after superficial keratectomy (SK) for Salzmann nodular degeneration (SND). Methods: This was an observational retrospective study. Pre- and post-operative data, including best spectacle-corrected visual acuity (BCVA), refraction, and Pentacam® topography scans, were analysed. Changes in keratometry (K), wavefront aberrations, and corneal optical densitometry (COD) were evaluated. Results: A total of 21 eyes of 17 patients who underwent SK for SND were included. At an average follow-up of 6.3 ± 4.4 months, there was a significant reduction in RMS (root mean square) values for total wavefront aberrations after surgery (mean reduction: -3.89 ± 4.08 μm, p = 0.001), lower-order aberrations (mean reduction: -3.47 ± 3.52 μm, p = 0.001), and higher-order aberrations (mean: -0.42 ± 0.58 μm, p < 0.001). There was a significant improvement in BCVA (mean change: 0.27 ± 0.31 logMAR, p < 0.001) and spherical equivalent (mean change: -2.09 ± 2.73 D, p = 0.002), and a reduction in refractive cylinder (mean reduction: -0.85 ± 1.14 D, p = 0.008). There was a significant reduction in corneal astigmatism (mean reduction 1.04 ± 2.88 D; p = 0.041), and an increase in flat keratometry (mean change 1.46 ± 3.10 D; p = 0.029). Lastly, there was a significant decrease in total COD values in all zones except for the central 2 mm (p < 0.05) and in the overall total 12 mm cornea (p = 0.035). Conclusions: SK for SND resulted in better visual acuity and potentially improved quality as suggested by the reduction in corneal aberrations and improvement in corneal regularity and transparency.