The Effects of Whole-Corneal and Whole-Eye Higher Order Aberrations on the Discrepancy Between Refractive and Corneal Astigmatism in Otherwise Healthy Candidates for Refractive Surgery.

PURPOSE: To evaluate the effect of different whole-corneal and whole-eye higher order aberrations (HOAs) on levels of axis discrepancy. METHODS: This was a retrospective study including healthy candidates for refractive surgery, with one eye being randomly selected. A total of 360 eyes were included. Whole-corneal and whole-eye HOAs were measured twice with a Pentacam AXL Wave (Oculus Optikgeräte GmbH), and subjective manifest refraction was obtained. Axis discrepancy was defined as the absolute difference between Total Corneal Refractive Power flat keratometry axis and manifest refractive axis. Two multiple linear regression models that sought to explore the effect of HOAs in predicting axis discrepancy while adjusting for corneal and refractive confounders were built. RESULTS: Mean age was 29.1 ± 5.8 years and 63.9% of the patients were women. Mean manifest sphere and cylinder were -3.09 ± 2.36 and -1.45 ± 1.37 diopters (D), respectively. Mean cylinder axis discrepancy was 14.4 ± 14.5°. On multiple linear regression, the only variables significantly associated with axis discrepancy were corneal cylinder and corneal lower order aberrations [F(5,339) = 29.746; P < .001; adjusted R2 = 0.295]. Lower levels of corneal cylinder are by far the main contributor to astigmatism axis mismatch (ß = -1.164). There was not a single HOA, either corneal or ocular, that significantly loaded into any models. CONCLUSIONS: Astigmatism axis mismatch decreases rapidly with increasing levels of corneal astigmatism. Corneal and whole-eye HOAs have no role in astigmatism axis mismatch in healthy candidates for refractive surgery. [J Refract Surg. 2024;40(2):e89-e97.].

Determination of the repeatability of corneal densitometry as measured with a Scheimpflug camera device in refractive surgery candidates.

Purpose: Corneal densitometry analysis provides an objective measurement of corneal transparency in patients undergoing photorefractive keratectomy (PRK). To date, no study that focuses on determining the reliability and smallest real difference (SRD), specifically in PRK candidates, has been published. Methods: The study was conducted at Clínica de Oftalmología Sandiego, Medellín, Colombia. This was a prospective and analytical study. Refractive surgery candidates underwent Pentacam measurements twice with five minutes of difference. Repeatability of measurements was evaluated for every area using Wilcoxon signed-rank test, Spearman's rank-order correlation, and the intraclass correlation coefficient, followed by a within-subjects factor (Sw) finishing with a determination of the SRD for all areas. Bland-Altman plots were created and analyzed. Results: A total of 110 eyes were included. The mean total densitometry was 18.67 ± 1.56 grayscale units (GSU) and 18.65 ± 1.49 GSU for the first and second measurements, respectively. Wilcoxon was non-significant (P > 0.05) while the intraclass correlation coefficient demonstrated an excellent agreement. SRD ranged from 0.21 GSU (posterior × 6-10 mm) to 1.79 GSU (total × 10-12 mm). Anterior depths and 10-12 mm annulus had consistently more variability and greater (worse) SRD. The 10-12 mm annulus showed great dispersion on the Bland-Altman plots. Conclusion: Corneal densitometry has an excellent repeatability in refractive surgery candidates for areas below 10 mm. Any densitometry change ≥1.0 GSU in areas under 10 mm should be considered as well above measurement noise and corresponding to a real change in measured parameters. The 10-12 mm area does not seem to be reliable enough in refractive surgery candidates to warrant surveillance after corneal-based surgery.

Cefalea: una consulta frecuente en oftalmología. Guía práctica para oftalmólogos / Headache: a frequent consultation in ophthalmology. Practical guide for ophthalmologists

La cefalea es un síntoma frecuente de consulta en oftalmología. Cuando el dolor se extiende al globo ocular o a la órbita, el paciente asume que los ojos son la causa del dolor. Esta revisión busca describir las causas de cefalea más comunes para poder realizar un diagnóstico diferencial adecuado y tener claro cuáles son las indicaciones para referir los pacientes a oftalmología.

Headache is a frequent symptom for consultation in ophthalmology. When the pain refers to the eyeball or orbit, the patient assumes the eye is the cause of the pain. This review focuses on describing the most common causes of headache to make a correct differential diagnosis and be clear when to refer patients to ophthalmology.

Mejoría de la calidad visual, corneal y refractiva en queratocono por medio del protocolo de Atenas / Improvement of visual, corneal, and refractive quality in keratoconus through the Athens protocol

Se presenta el caso de un paciente con queratocono, con distorsión corneal moderada, quien es sometido a cirugía PRK guiada por topografía con crosslinking (protocolo de Atenas), con un excelente resultado anatómico y funcional. Se reportan las imágenes de tomografía de Scheimpflug y la simulación de calidad visual basada en aberrometría Hartmann-Shack.

This article presents the case of a keratoconus patient with moderate corneal distortion who underwent simultaneous topography-guided PRK and corneal crosslinking (Athens protocol), achieving an excellent anatomical and visual improvement. Scheimpflug tomography and Harmann-Shack aberrometry-based visual simulations are presented.