Abstract

Purpose: To evaluate the changes in preoperative and postoperative corneal densitometry and its impact on visual outcomes in keratoconus patients undergoing isotonic collagen crosslinking therapy in a Western population. This study uniquely focuses on a population in Western India, adding valuable regional data to existing research. Methods: This prospective interventional study was conducted at Alakh Nayan Mandir Eye Institute, Udaipur, involving 50 eyes from 39 patients with progressive keratoconus treated with isotonic collagen crosslinking therapy. The study spanned from June 16, 2020, to June 16, 2021. Preoperative and postoperative assessments included uncorrected visual acuity (UCVA), bestcorrected visual acuity (BCVA), corneal densitometry, and slit-lamp biomicroscopy. Corneal densitometry was measured using Scheimpflug tomography (Pentacam HR, Oculus Optikgeräte GmbH) at 1, 3, and 6 months postoperatively. Statistical analysis was performed using EPI INFO Ver.7 software. Results: The mean age of patients was 19.90 ± 4.98 years, with a nearly equal gender distribution (56% female, 44% male). Baseline mean logMAR visual acuity (UCVA) was 0.63 ± 0.32, and mean BCVA was 0.16 ± 0.15. At 6 months, UCVA was 0.59 ± 0.37 (p = 0.564) and BCVA was 0.12 ± 0.15 (p = 0.186). The mean Km value decreased from 49.10 ± 3.27 preoperatively to 47.81 ± 3.53 at 6 months (p = 0.293). Corneal pachymetry decreased significantly from 449.80 ± 43.48 to 418.96 ± 48.07 (p < 0.001). Corneal densitometry at 0-2 mm increased from 16.12 ± 2.08 to 21.85 ± 8.81 (p < 0.001), and at 2-6 mm from 13.94 ± 1.61 to 15.89 ± 5.61 (p < 0.001). Corneal haze peaked at 1 month postoperatively and gradually declined but remained elevated compared to baseline at 6 months. Conclusions: Isotonic collagen crosslinking therapy in keratoconus patients resulted in significant changes in corneal densitometry and pachymetry, with a transient increase in corneal haze peaking at 1 month and gradual reduction by 6 months. Visual acuity showed stabilization postoperatively, with no significant decrease in topographic and keratometric indices. The inverse correlation between corneal pachymetry and densitometry suggests structural changes in the corneal stroma following crosslinking. This study adds unique regional data from Western India to the broader understanding of keratoconus treatment outcomes.