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

Cataratas en pacientes sometidos a implante de lente intraocular fáquico: una ocurrencia muy poco habitual / Cataract in patients undergoing phakic intraocular lens implantation: an uncommon event

Se presenta el caso de dos pacientes con vault anormalmente bajo luego del implante de lentes intraoculares fáquicos. Se reportan las imágenes de Scheimpflug y retroiluminación que han permitido el diagnóstico temprano.

We present the cases of two patients who developed an abnormally low vault and subcapsular anterior cataracts after phakic intraocular lens implantation. Scheimpflug and retroillumination images are reported