The Sub400 Protocol Corneal Cross-Linking In Thin Corneas With Keratoconus: 12-Month Follow-Up

Published 2024 - 42nd Congress of the ESCRS

Reference: PP23.08 | Type: Free paper | DOI: 10.82333/d91k-1289

Authors: Mariana Domingues Vaz* ¹ , Tomás Loureiro ¹ , Pedro Carreira ¹ , Sandra Barros ¹ , Ana Miranda ¹ , Inês Machado ¹ , Nuno Campos ¹

¹Oftalmology ,HGO,Almada,Portugal

Purpose

To evaluate the 1^st year outcome of the sub400 protocol corneal cross-linking in thin corneas with progressive keratoconus.

Setting

Hospital Garcia da Orta

Methods

Patients with history of progressive keratoconus with corneal stromal thickness less than 400um and best corrected distance visual acuity less than 0.8 were included. Ultraviolet irradiation (3mW/cm²) time was defined according to stromal thickness. Patient evaluation included spectacle best-corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), keratometry and densitometry with Pentacam (Oculus), corneal thickness and demarcation line (DL) depth with Cirrus (Zeiss) and corneal density with specular biomicroscopy. Pre-operative and postoperative 12-month evaluations were considered for statistical purposes. Keratoconus progression was evaluated by ABCD grading system.

Results

Twenty eyes were included. The mean age was 27 ± 7.2 (18 – 36) years. 85% of eyes showed no progression at 12 months. The mean stromal corneal thickness was 342 ± 75 um (287 – 378). CDVA (0.33 ± 0.42 vs. 0.28 ± 0.35, p=0.66) and UDVA (0.11 ± 0.32 vs. 0.09 ± 0.38, p=0.72) did not change. Kmax (-2.3 ± 3.4 D, p<0.01) and stromal thickness (-12.2 ± 24.2um) decreased. Corneal densitometry (+2.1 ± 2.21GSU) increased. A positive correlation between DL depth and irradiation time was found (r= +0.32, p=0.03). Endothelial cell density did not significatively change (-121cel/mm², p=0.71).

Conclusions

This paper shows a short-term safety efficacy of the sub400 protocol corneal cross-linking in thin corneas with progressive keratoconus. The rate of success at 12-months was 85%. This protocol seems to be harmful in terms of visual acuity and corneal endothelial viability.