Clinical Ophthalmology (Aug 2019)
Correlation between corneal stromal demarcation line depth and topographic outcomes after two pulsed-light-accelerated crosslinking protocols
Abstract
Julio C Hernandez-Camarena,1 Enrique O Graue-Hernandez,2 Denise Loya-García,1 Raul E Ruiz-Lozano,1 Jorge E Valdez-García11Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Monterrey, NL 64710, Mexico; 2Department of Cornea and Refractive Surgery, Institute of Ophthalmology Conde de Valenciana, Mexico City, MexicoCorrespondence: Julio C Hernandez-CamarenaCornea and Refractive Surgery Service, Zambrano-Hellion Hospital, Batallon de San Patricio 112, 1st Floor East, Real de San Agustín, San Pedro Garza Garcia, Nuevo Leon 66278, MexicoTel +52 1 818 888 0550Fax +52 1 818 888 0555Email [email protected]: To report the visual and topographic outcomes of two pulsed-light-accelerated CXL (A-CXL) protocols at a 12-month follow-up and their correlation with the corneal stromal demarcation line (DL) depth.Patients and methods: Retrospective comparative cohort of patients with documented progressive keratoconus were included. Two epi-off pulsed-light [1s on–1s off] A-CXL protocols were compared: irradiance 30*8 and 45*5:20 (fluence 7.2 J/cm2,). UDVA, CDVA, spherical equivalent (SE), topographic astigmatism, Kmin, Kmax, Km, central corneal thickness (CCT), thinnest pachymetry (TCT) and endothelial cell density (ECD) were measured preoperatively and months 1, 3, 6 and 12 postoperative. Corneal DL was measured 1 month postoperatively using anterior segment optical coherence tomography.Results: Fifty eyes (27 patients): 22 eyes in group A-CXL (30*8), 28 eyes in group A-CXL (45*5:20). Mean age (years) was 19.04±4.71 and 20.32±4.57. DL depth (μm) at month 1 was 200.63±10.01 μm and 184.53±19.68 μm for group A-CXL (30*8) and group A-CXL (45*5:20), respectively (p<0.001). Significant improvement in CDVA, topographic astigmatism, Kmin, Kmax and Km was observed in both groups (no significant difference between groups) and no significant changes were observed in CCT, TCT and ECD with regard to baseline. Over 85% of the eyes in both protocols achieved stabilization or improvement in maximum K at the end of the follow-up. No significant correlations between DL and any visual or topographic outcomes were observed at 12 months.Conclusion: No correlation between DL depth and visual or topographic outcomes was observed on either protocol. Although significant improvement on CDVA, topographic astigmatism, Kmin, Kmax and Km was observed in both groups at 12 months, further research is needed to assure safety and effectiveness at stabilizing keratoconus progression.Keywords: keratoconus, accelerated corneal crosslinking, corneal stromal demarcation line, optical coherence tomography, topographic stabilization
