Comparison between three methods to value lower tear meniscus measured by image software

Abstract

To measure different parameters of lower tear meniscus height (TMH) by using photography with open software of measurement. TMH was addressed from lower eyelid to the top of the meniscus (absolute TMH) and to the brightest meniscus reflex (reflex TMH). 121 young healthy subjects were included in the study. The lower tear meniscus was videotaped by a digital camera attached to a slit lamp. Three videos were recorded in central meniscus portion on three different methods: slit lamp without fluorescein instillation, slit lamp with fluorescein instillation and TearscopeTM without fluorescein instillation. Then, a masked observed obtained an image from each video and measured TMH by using open source software of measurement based on Java (NIH ImageJ). Absolute central (TMH-CA), absolute with fluorescein (TMH-F) and absolute using the Tearscope (TMH-Tc) were compared each other as well as reflex central (TMH-CR) and reflex Tearscope (TMH-TcR). Mean ± S.D. values of TMH-CA, TMH-CR, TMH-F, TMH-Tc and TMH-TcR of 0.209 ± 0.049, 0.139 ± 0.031, 0.222 ± 0.058, 0.175 ± 0.045 and 0.109 ± 0.029 mm, respectively were found. Paired t-test was performed for the relationship between TMH-CA – TMH-CR, TMH-CA – TMH-F, TMH-CA – TMH-Tc, TMH-F – TMH-Tc, TMH-Tc – TMH-TcR and TMH-CR – TMH-TcR. In all cases, it was found a significant difference between both variables (all p < 0.008). This study showed a useful tool to objectively measure TMH by photography. Eye care professionals should maintain the same TMH parameter in the follow-up visits, due to the difference between them.