Effect Of Corneal Vital Dyes On Pachymetry Measured By Scheimpflug Technology
Published 2024 - 42nd Congress of the ESCRS
Reference: PO268 | Type: Poster | DOI: 10.82333/hbqw-2881
Authors: Ignacio López Miñarro* 1 , María Gómez Tomás 1 , Isabel Bermejo Rodríguez 1 , Laura Prieto Domínguez 1 , Sebastián Martínez Tapia 1 , Santiago Mejía Freire 1 , David Galarreta Mira 1
1OPHTHALMOLOGY,HOSPITAL CLINICO UNIVERSITARIO DE VALLADOLID,VALLADOLID,Spain
Purpose
To evaluate and to compare the changes induced in central corneal thickness (CCT) measurements at different times by fluorescein sodium 20 mg/mL (Bausch & Lomb, Bridgewater, NJ, USA), riboflavin 2.5mg/ml (Ribomark ®, Brill Pharma S.L, Barcelona, Spain) and lissamine green 5mg/mL (magistral formulation, Farmacia Javier Corral García-Segura, Madrid, Spain) eye drops.
Setting
Department of Cornea and External Diseases, Hospital Clínico Universitario de Valladolid, Valladolid, Spain.
Methods
Twenty-three healthy volunteers were measured with a Galilei G6® Dual Scheimpflug topographer (Ziemer Ophthalmic Systems, Port, Switzerland). Baseline CCT measurements were performed 1 minute after instillation of 25 µL of BSS (NaCl 0.9%). CCT was measured at 1, 5, and 15 minutes after application of riboflavin, fluorescein, and lissamine green eye drops in patients. Each vital dye was applied 24 hours apart to avoid interaction, and measurements were consistently taken at the same time of day for each patient.
Results
Mean baseline CCT was 542.8±35.6 µm. Mean corneal thickness after instillation of riboflavin (N=46) was 561.9±35.5, 552.1±35.7 and 545.8±35.5 µm, with fluorescein (N=42) was 558.4±41.7, 562.3±33.6 and 557.6±36.1 µm, with lissamine green (N=42) was 544.9±33.6, 543.6±34.6 and 545.3±34.5 µm, at 1 minute, 5 minutes and 15 minutes respectively. Sixty-one of fluorescein measurements had to be rejected due to artifacts.
The change in corneal thickness observed with riboflavin was statistically significant (19±7, 9.2±6.3, 2.9±5.7 µm resp., p<0.005). The change induced by fluorescein was also statistically significant (21.3±10, 16.7±25.6, 11.2±6.8 µm resp., p<0.05). There were no statistically significant changes with lissamine green.
Conclusions
Riboflavin and fluorescein eyedrops induced a temporal overestimation in CCT values. Fluorescein drops caused a large number of artifacts that make the measurements unreliable even after 15 minutes. Lissamine green eyedrops do not produce significant changes in CCT measurement.
Ocular surface examination with vital dyes can seriously affect the CCT values measured with Dual Scheimpflug topographer. Lissamine green seems to be the best dye to avoid misunderstandings in cases in which pachymetries values can influence the therapeutic approach in diseases like keratoconus.