Abstract
Purpose: :
To compare the precorneal tear film thickness using Pentacam®(Oculus, Wetzlar, Germany) with fluorescein between dry eye group and normal group and to examine the relationship between the tear film thickness and other parameters for dry eye.
Methods: :
Participants (25 patients, 31 eyes with dry eye and 23 patients, 31 normal eyes) were scanned once with Pentacam® and re-scanned after instillation of 1µm, 0.1% fluorescein in the lower conjunctival sac with micropipette. The difference of thickness between two measurements (before and after fluorescein staining) was defined precorneal tear film thickness. The tear film thickness was evaluated and analyzed the correlation with fluorescein tear break up time (FBUT), Schirmer I test (without anesthesia), ocular surface disease index (OSDI).
Results: :
The mean precorneal tear film in dry eyes(23.2 ± 11.25 µm) was significantly thinner than in normal eyes(35.5 ± 10.0 µm) (P<0.01). In dry eye group, OSDI scores did not correlate with objective clinical measures of dry eye (FBUT, Schirmer I test). Statistically significant correlation was detected for the OSDI(R=-0.46, P<0.01). However, the correlation coefficients between the tear film thickness and FBUT/ Schirmer I test were not significant (R=0.26, P=0.16, R=0.02, P=0.9, respectively).
Conclusions: :
The tear film in dry eyes tends to be thinner than in normal control. There was a strong correlation between the precorneal tear film thickness and subjective symptom score(OSDI). The measurement of tear film thickness using the Pentacam® with fluorescein could be considered as a new method for diagnosis of dry eye in company with traditional objective measurements.
Keywords: cornea: tears/tear film/dry eye • imaging/image analysis: clinical • topography