Clinical context

Visual acuity alone is insufficient when judging corneal disease or surgery. Topography and tomography, surface regularity, biomechanics, endothelial cell density, quality of vision and stability all matter. After refractive procedures, epithelial healing, dry eye, haze, ectasia and the need for enhancement should be assessed separately.

What was studied

Visual loss in keratoconus reflects not only sphere and cylinder but also coma and other higher-order aberrations. The Tel-Aviv protocol combines a 50–60-µm epithelial PRK with myopic spherical and astigmatic components, followed by cross-linking. Records from treatment between 2021 and 2024 were compared before and after surgery. The analysis included 55 eyes of 50 patients; mean age was 29.45±10.5 years, range 14–53. Keratometry, refraction, corrected acuity, epithelial thickness and corneal aberrations were assessed.

How the evidence was produced

A cohort study describes how outcomes are associated with an exposure or treatment in an observed clinical population. This design is useful for routine practice, uncommon events and longer follow-up, but it remains vulnerable to confounding by indication, baseline risk differences and missing data. An association should not automatically be interpreted as a causal effect.

Key result Corrected distance acuity improved from 0.23±0.14 to 0.13±0.125 logMAR, P<.001. Vertical coma, vertical trefoil, spherical aberration, residual aberrations and total-HOA RMS all decreased significantly, P<.05. Epithelial thickness remained stable. Corneal symmetry indices and the ectasia index also improved. Reduction in vertical coma was moderately correlated with CDVA improvement, r=.34, P=.01. Mean follow-up was 262.73±232.1 days, while the abstract describes the principal preoperative versus approximately six-month comparison.

How to interpret the result

The findings are consistent with limited therapeutic ablation making the optical surface more regular while CXL aims to stabilize shape. The coma–acuity correlation is plausible but modest; other factors also determine vision. A before-and-after improvement does not prove superiority over CXL alone, another customized approach or observation. The goal in keratoconus differs from elective refractive correction: tissue preservation, progression control and realistic limits on correction are central.

Clinical applicability

The study may refine technique selection and informed discussion, but its conclusions depend on baseline corneal shape, stromal thickness, equipment, nomogram and surgeon experience. Applicability requires comparison of these factors and attention to variability, uncommon complications and follow-up duration rather than mean values alone.

Limitations

A retrospective uncontrolled design is vulnerable to selection, regression to the mean and time effects. The sample was small, included five fellow-eye pairs and had highly variable follow-up. The abstract omits Kmax, spherical-equivalent change and absolute values for every HOA; multiple tests increase chance findings. Stable epithelial thickness does not establish disease stability or safety. Verify keratoconus and progression criteria, stromal ablation depth, residual thickness, CXL and mitomycin protocols, haze, attrition, paired analysis, wavefront repeatability, complications, funding and conflicts.

What to verify in the source

Use the DOI below to verify complete methods, result tables, funding and conflicts of interest.