Lipid Layer Thickness in Precorneal Tear Film.

Choi, S H; Kim, N J; Jung, S Y; Cha, M B

Original Article

Journal of the Korean Ophthalmological Society 1997;38(2):195-200.
Published online February 1, 1997.

Lipid Layer Thickness in Precorneal Tear Film.

S H Choi, N J Kim, S Y Jung, M B Cha

Department of Ophthalmology College of Medicine Chungnam National Univirsity Taejon, Korea.

각막앞눈물막의 지방층 두계

최시환(Choi S.H),김남중(Kim N.J),정상엽(Jung S.Y),차무병(Cha M.B)

Abstract

Precorneal tear film consists of a mucinous layer, an aqueous layer and a lipid layer. The lipid layer plays the most essential role in preventing the desiccation of the aqueous layer. The thickness of the lipid layer can be measured by means of its interference pattern in the slit lamp. If the lipid layer is just over 134 nm thick, the reflected light from anterior surface interferes with the reflected pencil of rays from its posterior surface. The thickness of the lipid layer can be calculated by 134 mm multiplied by the ratio of narrowed palpebral fissure height to the fully opened one. We studied the thickness of the lipid layer and the correlation among the lipid layer, tear flim break-up time(BUT), and Schirmer test. The thickness of the lipid layer and BUT were measured three times a day for 3 days and the Schirmer test was measured once a day for three days in 75 normal subjects. The reproducibility of the lipid test is recorded by Cronbach alpha(a) value of SAS program. The reproducibility is high when the alpha value is near to 1.0.Cronbach a value of the lipid test and BUT was 0.606 and 0.688, respectively. The mean thickness of the lipid layer was 73.53 mm. The Pearson correlation coefficient between the lipid test and BUT, and the lipid test and the Schirmer test was 0.089 and 0.025, respectively.

Key Words: fLipid test;Precorneal tear film;Reproducibility