Influence of Conjunctival Folds on Calculated Tear Meniscus Volume Along the Lower Eyelid

Abstract

-nc-nd/4.0/ 2 Purpose: When calculating tear meniscus volume (TMV), tear meniscus height (TMH), radius (TMR) and cross-sectional area (TMA) are mostly measured at the centre of the lower lid margin. Lid-parallel conjunctival folds (LIPCOF) are known to influence the tear meniscus regularity. The aim of this study was to analyse the influence of LIPCOF on TMA measured by optical coherence tomography (OCT) and consequently, the calculated tear meniscus volume (TMV).Methods: Using OCT (Cirrus-HD; Carl Zeiss Meditec, Jena, Germany), TMH, TMR and TMA of 42 subjects (13M, 29F; mean age 27.3 SD±8.4 years) were measured directly below the pupil centre, plus at temporal and nasal locations perpendicularly below the limbus, where LIPCOF was also evaluated and graded. TMV for the different locations was calculated. Correlations between LIPCOF and the tear meniscus parameters were analysed using the Spearman Rank-Order coefficients.Differences between tear meniscus parameters at the different locations were evaluated by the paired t-test.Results: Central TMV (5.30±1.42x10 -2 µl/mm) was significantly positively correlated to LIPCOFsum (2.4±1.2) (r=0.422; p<0.05). The calculated temporal TMV was greater by 0.53x10 -2 µl/mm compared to the central TMV (p=0.037), while there was no significant difference in tear volume between the other locations.

Evaluation of tear meniscus height using different clinical methods

“…4 Measurements of tear meniscus height (TMH), tear meniscus radius (TMR) or tear meniscus cross-sectional area (TMA) are generally accepted methods to evaluate tear film volume, especially in dry eye diagnosis and management. 4,5 Tear meniscus parameters can be influenced by time after a blink, diurnal variations, measurement location along the lids, presence of conjunctival folds, climate, and illumination technique. 4,6,7 A TMH of 0.20 mm or below is assumed to be an indicator for aqueous deficiency.…”

Efficacy of Strip Meniscometry for Detecting Lacrimal Obstructive Diseases Among Patients With Epiphora

“…We thought the difference was derived from surgical differences. Furthermore, OCT-based measurements of the tear meniscus are influenced by trichiasis, entropion, ectropion, eye position, and particularly by conjunctivochalasis or conjunctival folds parallel to the lid 12. In one study, the tear meniscus areas at the nasal, center, and temporal locations differed significantly in patients with conjunctivochalasis 13.…”

BCLA CLEAR - Effect of contact lens materials and designs on the anatomy and physiology of the eye

“…LIPCOF interfere with tear meniscus assessment, either of the tear meniscus radius [165], height [165,166] volume [167,168], curvature, depth or cross-sectional area [162]. LIPCOF may affect tear film mixing, spreading and thus ocular surface lubrication, although the precise mechanism for this is unclear [169].…”