Purpose:
To report a novel method for quantitative evaluation of tearfluorescein clearance (TFC) rate using Pentacam Scheimpflugimaging system.
Methods:
Thirty patients with dry eye symptoms and thirty age-matchedasymptomatic control subjects were enrolled in this prospectivestudy. TFC test and SchirmerItest was performed in each participant.The TFC rate was evaluated with Pentacam by measuring reflectivelight intensity (RLI) of fluorescent tear film 3 minutes afterinstillation of 2 µl 1% sodium fluorescein into inferiorcul-de-sac.
Results:
Significantly decreased TFC rate (indicated by a higher tearfilm RLI 41.1±14.5, P < 0.0001) and lower SchirmerScore (7.0±6.4 mm/5min, P < 0.0001) were observedin symptomatic patients than those observed in normal controls(tear film RLI 17.9±13.5, Schirmer Score 18.4±9.6mm/5min). An inverse correlation was found between tear filmRLI and Schirmer Score (Spearman’s rho = -0.45 , P= 0.0003).TFC test showed a slightly better value than SchirmerItest fordiscriminating symptomatic patients from normal controls. Thecutoff value of tear film RLI 31.6 had 80 % sensitivity and93% specificity.
Conclusions:
This novel method is convenient and practical for tear fluoresceinclearance test in clinic, and it will further the investigationof tear clearance under physiological and pathological conditions.
Keywords: cornea: tears/tear film/dry eye • imaging/image analysis: clinical • cornea: clinical science