Lid-parallel conjunctival fold (LIPCOF) morphology imaged by optical coherence tomography and its relationship to LIPCOF grade.

Abstract

Purpose: Lid-parallel conjunctival folds (LIPCOF) are a well-accepted clinical sign in dry eye diagnosis. Commonly, LIPCOF is classified by grading the number of folds observed by slit-lamp microscope. This study investigated the relationship between subjective grading scale and LIPCOF morphology imaged by optical coherence tomography (OCT). Methods: Temporal and nasal LIPCOF of 42 subjects (mean age 27.3±8.4 (SD) years; 13M, 29F) were observed and classified by an experienced optometrist using the Pult LIPCOF grading scale (0: no permanent, lid-parallel conjunctival fold; 1: one fold; 2: two folds, 3: three or more folds). Additionally, LIPCOF cross-sectional area (LIPCOF-A) and fold count (LIPCOF-C), as imaged by OCT (Cirrus HD; Carl Zeiss Meditec, Jena, Germany), were analysed with ImageJ 1.50 (http://rsbweb.nih.gov/ij). Correlations between subjective grading and LIPCOF-A and LIPCOF-C were analysed by Spearman correlation, differences between subjective grading and LIPCOF-C were analysed by Wilcoxon test. Results: For temporal and nasal sectors, mean subjective LIPCOF grade was 1.43±0.86 grade units and 0.57±0.80 grade units, mean LIPCOF-C was 1.67±0.82 folds and 0.69±0.78 folds, and mean LIPCOF-A was 0.0676±0.0236mm2 and 0.0389±0.0352mm2, respectively. Subjective temporal and nasal LIPCOF grade was significantly correlated to LIPCOF-C (r=0.610, p<0.001 and r=0.645, p<0.001, respectively), and to LIPCOF-A (r=0.612, p<0.001 and r=0.583, p<0.001, respectively). LIPCOF-C was not statistical different to subjective LIPCOF grade (p=0.07 and p=0.239; temporal and nasal sectors, respectively). Conclusions: OCT allows for better imaging of finer details of LIPCOF morphology, and especially of LIPCOF area. OCT evaluation of LIPCOF area correlated well with subjective grading and appears to be a promising objective method for LIPCOF classification.