Does the palpebral morphology influence the tear meniscus height between Caucasian and Asian eyes?

The central lower TMH is used as a clinical measure of tear volume in the assessment of contact lens candidates and patients with dry eyes. Ethnic differences in eyelid morphology may influence the measurement of the TMH. Furthermore, with the advent of larger contact lenses, such as scleral lenses, it would be of clinical value to assess the TMH centrally and peripherally. The purpose of this study was to evaluate and compare the TMH at different positions along the palpebral margin between Caucasian and Asian eyes.

This prospective study evaluated the lower TMH in five positions (central, temporal and nasal limbus and temporal and nasal periphery) of the right eye using the Keratograph 5M (Oculus) instrument in Caucasian and Asian participants between 10 am and 12 pm . The TMH at each position was taken three times and averaged and analyzed using a 5 × 2 repeated-measures analysis of variance.

Central TMH did not differ significantly ( F = 0.02, p=0.88) in Caucasians (n = 20, aged 24.45 [2.30] years, TMH 0.320 [0.052] mm) and Asians (n = 20, aged 22.25 [3.43] years, TMH 0.325 [0.048] mm). A difference was noted with respect to TMH positions along the lid margin ( F = 64.17, p<0.001), independent of ethnicity ( F = 2.15, p=0.15). A post hoc analysis revealed a significantly higher TMH temporally when compared with centrally or nasally (p<0.001).

This study demonstrated the similarity of the central TMH and the differences in the peripheral TMH within Caucasian and Asian eyes. This may be clinically relevant when using the Tear Film & Ocular Surface Society Dry Eye Workshop II diagnostic algorithm for dry eyes and when fitting scleral contact lenses. Future studies need to consider that ethnic differences may exist for certain tests in order to personalize the care and management of each patient.