Impact of conjunctival folds on central tear meniscus height

To analyze the effect of temporal and nasal lid-parallel conjunctival folds (LIPCOF) on the central tear meniscus height (TMH).

Tear meniscus height of 40 eyes of 20 subjects (15 female, median age: 39 years) was evaluated by the Tearscope Plus. Temporal and nasal LIPCOF scores were observed by slit lamp (SL) examination. The cross-sectional LIPCOF area (LA) was measured by a modified Scheimpflug camera. Tear meniscus was colored by fluorescein and TM fluorescence (TMF) was evaluated by SL using a 5-grade pictorial scale. Tear meniscus fluorescence was defined by its intensity, height, and regularity at the LIPCOF area in comparison to the central TMF. Correlations between variables were analyzed by Pearson correlation for parametric data or Spearman rank for nonparametric variables.

Inferiorly, central TMH was significantly correlated to temporal LA (Pearson: r = 0.519, P = 0.001) and nasal LA (r = 0.567, P = 0.002). Superiorly, central TMH was significantly correlated with temporal LA (r = 0.352, P = 0.033), but not with nasal LA (r = 0.355, P = 0.075). Temporal LA was significantly correlated with temporal TMF (Spearman rank: r = 0.789, P < 0.001), and nasal LA was significantly correlated to nasal TMF (r =0.415, P = 0.008). Scores of LIPCOF were significantly correlated with TMF scores (Spearman rank: temporal, r = 0.837, P < 0001; nasal, r = 0.609, P < 0.001). Subjective LIPCOF grading was significantly correlated with LA (Spearman rank: temporal, r = 0.707, P < 0.001; nasal, r = 0.515, P = 0.001).

Lid-parallel conjunctival folds impact TMH evaluation. In patients with LIPCOF, the real tear film volume may be smaller than the TMH measurement suggests.