Contents lists available at ScienceDirect Contact Lens and Anterior Eye journal homepage: www.elsevier.com/locate/clae Comparison study of two different topical lubricants on tear meniscus and tear osmolarity in dry eye Emine Esra Karaca a, ⁎, Dilay Özek a , Özlem Evren Kemer b a Ankara City Hospital, Department of Ophthalmology, Ankara, Turkey b University of Health Sciences, Ankara City Hospital, Department of Ophthalmology, Ankara, Turkey ARTICLE INFO Keywords: Hyaluronic acid Ocular residency Optic coherence tomography Tear meniscus height Trehalose ABSTRACT Purpose: To compare the effect of single-drop administration of two different ophthalmic solutions on tear meniscus and tear osmolarity in patients with mild to moderate dry eye disease. Methods: This prospective study comprised of 122 patients with mild to moderate dry eye disease. These patients received a single dose of either unpreserved trehalose 3%, hyaluronic acid 0.15%, carbomer 0.25% (THeHA, Thealoz Duo Gel) (Group 1) or hyaluronic acid 0.3% (HA) (Group 2) gel-based lubricants. Tear meniscus (height and depth) were measured using anterior segment optic coherence tomography (AS−OCT) at baseline and 10, 60, 120, and 240 min. after instillation. Tear osmolarity, Schirmer I test, tear break-up time (TBUT), gel prop- erties, and patient comfort were evaluated 240 min. after instillation. Results: Tear meniscus height (TMH) and tear meniscus depth (TMD) showed a significant increase with both lubricants compared to the baseline (p < 0.001). This effect remained significant for up to 60 min. and 120 min. for the THeHA and HA 0.3% solutions, respectively (p < 0.05, for both). Mean comfort duration was 115.1 ± 20.1 min. in Group 1 and 148.3 ± 49.0 min in Group 2 (p < 0.001). Tear osmolarity, Schirmer I test, and TBUT were similar between the baseline and 240 min. for each group. Conclusions: The results of this study demonstrate that 0.3% HA remains on the ocular surface for longer than TH-HA. The longer ocular residency time also seems to correlate with a longer patient comfort duration. 1. Introduction Dry eye disease (DED) is highly prevalent throughout the world and is associated with tear instability, visual problems, and a reduction in the quality of life [1]. DED is a multifactorial disorder of the ocular surface characterized by a loss of homeostasis of the tear film, and accompanied by hyperosmolarity, inflammation, tear film instability, and neurosensory abnormalities, as described in the Tear Film and Ocular Surface Society's Dry Eye Workshop (TFOS DEWS) II Report [2]. The presence of any one of three specified signs: a reduced non-invasive tear break-up time; elevated or a large interocular disparity in osmo- larity; and ocular surface staining (of the cornea, conjunctiva or lid margin) in either eye, refers to the loss of homeostasis and confirms the diagnosis of DED [3]. DED directly affects the tear film and ocular surface. For that reason, objective methods are important for defining its severity and management protocol. Recently, a new method for the non-invasive measurement of tear meniscus based on optical coherence tomography has been developed. Anterior segment optical coherence tomography (AS−OCT) provides high resolution images of the cornea and anterior segment [4]. AS−OCT can also be used for tear meniscus assessment. Previous studies have shown that tear meniscus height correlates well with objective signs, as well as with subjective symptoms of DED [5,6]. DED management is complicated due to the multifactorial etiology of DED, and no single treatment regimen has been found that is suitable for all patients. According to TFOS DEWS II treatment begins with conventional lubricants for early-stage disease, with progression to more advanced therapies for more severe forms of DED [7]. Artificial tears have some specific properties for relieving the symptoms and signs of the patients: viscosity, lubricity, lipid content, electrolyte composi- tion, and osmoprotective effects [8,9]. Ocular residence time on the ocular surface is a feature of viscosity and describes the duration of effect of the artificial tears. Although artificial tears are a mainstay of DED management, frequent instillation is a common problem. This is due to the short residence time of lubricants on the ocular surface [10,11]. Increased viscosity will increase ocular residence time [12,13]. Hyaluronic acid (HA) is a natural lubricant and has excellent water- retaining properties, which makes it well-suited for use in artificial https://doi.org/10.1016/j.clae.2019.10.001 Received 30 June 2019; Received in revised form 1 October 2019; Accepted 1 October 2019 ⁎ Corresponding author. E-mail address: dremineesra@gmail.com (E.E. Karaca). Contact Lens and Anterior Eye xxx (xxxx) xxx–xxx 1367-0484/ © 2019 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved. Please cite this article as: Emine Esra Karaca, Dilay Özek and Özlem Evren Kemer, Contact Lens and Anterior Eye, https://doi.org/10.1016/j.clae.2019.10.001