{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,11]],"date-time":"2026-11-11T00:17:29Z","timestamp":1794356249123,"version":"4.9.0"},"reference-count":51,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2023,7,14]],"date-time":"2023-07-14T00:00:00Z","timestamp":1689292800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"King Saud University, Riyadh, Saudi Arabia","award":["RSPD2023R653"],"award-info":[{"award-number":["RSPD2023R653"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Medicina"],"abstract":"<jats:p>Background and Objectives: Dry eye disease (DED) is a multifactorial ailment of the tears and ocular surface. The purpose of this study was to assess the tear film physiology under controlled dry environmental conditions and compare the efficacy of oil-in-water emulsion drops on tear film parameters in protection and relief treatment modalities under low-humidity conditions. Emustil eye drops were used after exposure to a low-humidity environment in the relief method, whereas, in the protection method, the drops were applied before exposure to low humidity. Materials and Methods: 12 normal male subjects (mean age 34.0 \u00b1 7.0 years) were exposed to ultra-dry environmental conditions. A number of tear film measurements were carried out under desiccating environmental conditions in a controlled environment chamber (CEC), where the chamber temperature sat at 21 \u00b0C with a relative humidity (RH) of 5%. Keeler\u2019s TearScope Plus and an HIRCAL grid were used to assess the tear break-up time and lipid layer thickness (LLT), and the evaporation rate was evaluated using a Servomed EP3 Evaporimeter. Results: LLT measurements showed that the dry environment affected LLT significantly (p = 0.031). The median grade of LLT dropped from grade 3 (50\u201370 nm) at 40% RH to grade 2 (13\u201350 nm) at 5% RH. A significant increase in LLT was seen after both modes of treatment, with a median LLT grade of 3 when the Emustil was used for both protection (p = 0.004) and relief (p = 0.016). The mean tear evaporation rate in normal environmental conditions (40%) was 40.46 \u00b1 11.80 g\/m2\/h (0.11 \u00b5L\/min) and increased sharply to 83.77 \u00b1 20.37 g\/m2\/h (0.25 \u00b5L\/min) after exposure to the dry environment. A minimal decrease in tear film evaporation rate was seen in relief; however, statistical tests showed that the decrease in tear film evaporation rate was not significant. Mean NITBUT dropped from 13.6 s at 40% RH to 6.6 s at 5% RH (p = 0.002). All NITBUT measurements at 5% RH (with or without the instillation of Emustil) were significantly lower than those at 40%. The instillation of Emustil at 5% RH resulted in a significant improvement in NITBUT for protection (p = 0.016) but this was not the case for relief (p = 0.0.56). Conclusions: A control environmental chamber (CEC) enables the analysis of tear film parameters comparable to those found in dry eye patients. This enables us to examine the capability of oil in emulsion drops to manage tear film disruption in healthy individuals. This study suggests that using Emustil oil-in-water emulsion before exposure to a dry environment should be advocated for people who work in dry environments.<\/jats:p>","DOI":"10.3390\/medicina59071298","type":"journal-article","created":{"date-parts":[[2023,7,14]],"date-time":"2023-07-14T00:28:06Z","timestamp":1689294486000},"page":"1298","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Evaluation of Therapeutic Capability of Emustil Drops against Tear Film Complications under Dry Environmental Conditions in Healthy Individuals"],"prefix":"10.3390","volume":"59","author":[{"given":"Ali","family":"Abusharha","sequence":"first","affiliation":[{"name":"Department of Optometry, College of Applied Medical Sciences, King Saud University, Riyadh 11433, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ian E.","family":"Pearce","sequence":"additional","affiliation":[{"name":"Vision Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tayyaba","family":"Afsar","sequence":"additional","affiliation":[{"name":"Department of Community Health Sciences, College of Applied Medical Sciences, King Saud University, Riyadh 11433, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Suhail","family":"Razak","sequence":"additional","affiliation":[{"name":"Department of Community Health Sciences, College of Applied Medical Sciences, King Saud University, Riyadh 11433, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,7,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"51","DOI":"10.2147\/OPTO.S163303","article-title":"Ocular dryness assessment in Saudi employees working indoors and outdoors","volume":"10","author":"Fagehi","year":"2018","journal-title":"Clin. Optom."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"781683","DOI":"10.1155\/2014\/781683","article-title":"Aging: A predisposition to dry eyes","volume":"2014","author":"Sharma","year":"2014","journal-title":"J. Ophthalmol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1264","DOI":"10.1001\/archopht.118.9.1264","article-title":"Prevalence of and risk factors for dry eye syndrome","volume":"118","author":"Moss","year":"2000","journal-title":"Arch. Ophthalmol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1167\/tvst.9.5.25","article-title":"Climatic and environmental correlates of dry eye disease severity: A report from the dry eye assessment and management (DREAM) Study","volume":"9","author":"Berg","year":"2020","journal-title":"Transl. Vis. Sci. Technol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"162","DOI":"10.3109\/02713683.2014.966847","article-title":"Sex-steroid imbalance in females and dry eye","volume":"40","author":"Versura","year":"2015","journal-title":"Curr. Eye Res."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"347","DOI":"10.1016\/j.exer.2003.09.019","article-title":"Functional aspects of the tear film lipid layer","volume":"78","author":"Bron","year":"2004","journal-title":"Exp. Eye Res."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1097\/00003226-199603000-00004","article-title":"Effect of periocular humidity on the tear film lipid layer","volume":"15","author":"Korb","year":"1996","journal-title":"Cornea"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"429","DOI":"10.1097\/ICO.0b013e31826671ab","article-title":"The Effect of Low Humidity on the Human Tear Film","volume":"32","author":"Abusharha","year":"2012","journal-title":"Cornea"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"14","DOI":"10.3389\/fpubh.2020.00014","article-title":"Environmental and health impacts of air pollution: A review","volume":"8","author":"Manisalidis","year":"2020","journal-title":"Front. Public Health"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"2563","DOI":"10.1167\/iovs.03-1185","article-title":"Effect of environmental conditions on tear dynamics in soft contact lens wearers","volume":"45","author":"Maruyama","year":"2004","journal-title":"Investig. Ophthalmol. Vis. Sci."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Agarwal, P., Craig, J.P., and Rupenthal, I.D. (2021). Formulation considerations for the management of dry eye disease. Pharmaceutics, 13.","DOI":"10.3390\/pharmaceutics13020207"},{"key":"ref_12","first-page":"121","article-title":"Therapeutic challenges in ocular delivery of lipid based emulsion","volume":"5","author":"Tiwari","year":"2018","journal-title":"Egypt. J. Basic. Appl. Sci."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1097\/ICO.0b013e31821b71e6","article-title":"Effectiveness of artificial tears in the management of evaporative dry eye","volume":"31","author":"McCann","year":"2012","journal-title":"Cornea"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"594","DOI":"10.1097\/01.opx.0000171818.01353.8c","article-title":"The effect of two novel lubricant eye drops on tear film lipid layer thickness in subjects with dry eye symptoms","volume":"82","author":"Korb","year":"2005","journal-title":"Optom. Vis. Sci."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"38","DOI":"10.1097\/01.icl.0000247638.50568.c0","article-title":"Comparison of the efficacy of two lipid emulsion eyedrops in increasing tear film lipid layer thickness","volume":"33","author":"Scaffidi","year":"2007","journal-title":"Eye Contact Lens"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2","DOI":"10.1097\/01.ICL.0000140910.03095.FA","article-title":"Lid wiper epitheliopathy and dry eye symptoms","volume":"31","author":"Korb","year":"2005","journal-title":"Eye Contact Lens"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"S20","DOI":"10.1016\/j.ophtha.2017.05.031","article-title":"Meibomian gland disease: The role of gland dysfunction in dry eye disease","volume":"124","author":"Chhadva","year":"2017","journal-title":"Ophthalmology"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"367","DOI":"10.1016\/S0014-4835(03)00197-0","article-title":"The influence of eyelid temperature on the delivery of meibomian oil","volume":"78","author":"Nagymihalyi","year":"2004","journal-title":"Exp. Eye Res."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"139","DOI":"10.1111\/j.1475-1313.1989.tb00833.x","article-title":"Human tear film pre-rupture phase time (TP-RPT)- A non-invasive technique for evaluation the pre-corneal tear film using a novel keratometer mire","volume":"9","author":"Hirji","year":"1989","journal-title":"Ophthalmic Physiol. Opt."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"886","DOI":"10.1097\/00006324-199012000-00002","article-title":"Effect of Artificial Tear Solutions and Saline on Tear Film Evaporation","volume":"67","author":"Trees","year":"1990","journal-title":"Optom. Vis. Sci."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"S31","DOI":"10.1016\/S1367-0484(98)80035-0","article-title":"Non-invasive Tearscope Plus routine for contact lens fitting","volume":"21","author":"Guillon","year":"1998","journal-title":"Cont. Lens Anterior Eye"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"75","DOI":"10.1016\/S1542-0124(12)70081-2","article-title":"The definition and classification of dry eye disease: Report of the Definition and Classification Subcommittee of the international Dry Eye WorkShop","volume":"5","author":"Lemp","year":"2007","journal-title":"Ocul. Surf."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"441","DOI":"10.1111\/j.1755-3768.1986.tb06950.x","article-title":"Non-invasive tear film break-uptime: Sensitivity and specificity","volume":"64","author":"Mengher","year":"1986","journal-title":"Acta Ophthalmol."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Abusharha, A., Pearce, I.E., Afsar, T., Alsaqr, A., Fagehi, R., and Razak, S. (2023). Evaluation of different treatment modalities on the efficacy of hydroxypropyl Guar (HP-Guar) formulation on tear film stability (TFS) in subjects exposed to adverse environmental conditions. BMC Ophthalmol., 23.","DOI":"10.1186\/s12886-023-02977-3"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"276","DOI":"10.1016\/j.jtos.2017.05.008","article-title":"TFOS DEWS II definition and classification report","volume":"15","author":"Craig","year":"2017","journal-title":"Ocul. Surf."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"350","DOI":"10.1016\/j.ajo.2008.05.016","article-title":"Advances in understanding and managing dry eye disease","volume":"146","author":"Lemp","year":"2008","journal-title":"Am. J. Ophthalmol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"644","DOI":"10.1097\/00003226-200009000-00009","article-title":"The diagnosis and management of dry eye\u2014A twenty-five-year review","volume":"19","author":"Pflugfelder","year":"2000","journal-title":"Cornea"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"371","DOI":"10.1001\/archopht.1995.01100030127036","article-title":"Effects of preservative-free artificial tear solutions on corneal epithelial structure and function","volume":"113","author":"Ubels","year":"1995","journal-title":"Arch. Ophthalmol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"2149","DOI":"10.1185\/030079906X132640","article-title":"Increasing importance of dry eye syndrome and the ideal artificial tear: Consensus views from a roundtable discussion","volume":"22","author":"Asbell","year":"2006","journal-title":"Curr. Med. Res. Opin."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"647","DOI":"10.1089\/jop.2017.0052","article-title":"Relevance of lipid-based products in the management of dry eye disease","volume":"33","author":"Garrigue","year":"2017","journal-title":"J. Ocul. Pharmacol. Ther."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"507","DOI":"10.1111\/jphp.12132","article-title":"Topical delivery of ocular therapeutics: Carrier systems and physical methods","volume":"66","author":"Souza","year":"2014","journal-title":"J. Pharm. Pharmacol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"357","DOI":"10.1016\/j.ejpb.2004.03.033","article-title":"Biopharmaceutics: The potential of lipid emulsion for ocular delivery of lipophilic drugs","volume":"58","author":"Tamilvanan","year":"2004","journal-title":"Eur. J. Pharm. Biopharm."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"495","DOI":"10.1007\/978-1-4615-0717-8_69","article-title":"The effects of anionic and zwitterionic phospholipids on the tear film lipid layer","volume":"506","author":"Korb","year":"2002","journal-title":"Adv. Exp. Med. Biol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"802","DOI":"10.1097\/ICO.0b013e3181ca327e","article-title":"Effects of a new lipid tear substitute in a mouse model of dry eye","volume":"29","author":"Scifo","year":"2010","journal-title":"Cornea"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"631","DOI":"10.1016\/S0161-6420(99)00176-1","article-title":"Two multicenter, randomized studies of the efficacy and safety of cyclosporine ophthalmic emulsion in moderate to severe dry eye disease","volume":"107","author":"Sall","year":"2000","journal-title":"Ophthalmology"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"2421","DOI":"10.1016\/j.bbamem.2016.02.020","article-title":"Tear film lipid layer: A molecular level view","volume":"1858","author":"Cwiklik","year":"2016","journal-title":"Biochim. Biophys. Acta."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1076\/ceyr.26.2.89.14515","article-title":"Polar lipids in human meibomian gland secretions","volume":"26","author":"Shine","year":"2003","journal-title":"Curr. Eye Res."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"519","DOI":"10.1134\/S1063774506030242","article-title":"Estimation of the effect of relative humidity on protein crystallization","volume":"51","author":"Hudaverdyan","year":"2006","journal-title":"Crystallogr. Rep."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"293","DOI":"10.1007\/978-1-4615-2417-5_50","article-title":"Increase in tear film lipid layer thickness following treatment of meibomian gland dysfunction","volume":"350","author":"Korb","year":"1994","journal-title":"Adv. Exp. Med. Biol."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"189","DOI":"10.1097\/00006324-199603000-00011","article-title":"Tear film lipid layer formation: Implications for contact lens wear","volume":"73","author":"Korb","year":"1996","journal-title":"Optom. Vis. Sci."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"783","DOI":"10.1016\/j.ophtha.2003.07.008","article-title":"Sequential changes of lipid tear film after the instillation of a single drop of a new emulsion eye drop in dry eye patients","volume":"111","author":"Goto","year":"2004","journal-title":"Ophthalmology"},{"key":"ref_42","unstructured":"Anthony, J.B., Tiffany, J.M., Yokoi, N., and Gouveia, M.S. (2002). Lacrimal Gland, Tear Film, and Dry Eye Syndromes 3: Basic Science and Clinical Relevance Part A and B, Springer Science+Business Media."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"2747","DOI":"10.1167\/iovs.08-2459","article-title":"The contribution of lipid layer movement to tear film thinning and breakup","volume":"50","author":"Fink","year":"2009","journal-title":"Investig. Ophthalmol. Vis. Sci."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"S2461","DOI":"10.1088\/0953-8984\/16\/26\/019","article-title":"Effect of meibomian lipid layer on evaporation of tears","volume":"16","author":"Miano","year":"2004","journal-title":"J. Phys.-Condens. Matter"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1016\/S1542-0124(12)70150-7","article-title":"The contribution of meibomian disease to dry eye","volume":"2","author":"Bron","year":"2004","journal-title":"Ocul. Surf."},{"key":"ref_46","unstructured":"Salmon, J. (2019). Kanski\u2019s Clinical Ophthalmology, Elsevier Health Sciences. E-Book: A Systematic Approach."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"DES64","DOI":"10.1167\/iovs.17-23746","article-title":"Short tear film breakup time\u2013type dry eye","volume":"59","author":"Tsubota","year":"2018","journal-title":"Investig. Ophthalmol. Vis. Sci."},{"key":"ref_48","unstructured":"Prokopich, C., Hrynchak, P., and Elliott, D. (2007). Clinical Procedures in Primary Eye Care, Butterworth-Heinemann."},{"key":"ref_49","first-page":"2449","article-title":"Clinical trial results of a new emulsion-based dry eye treatment","volume":"44","author":"Vehige","year":"2003","journal-title":"Investig. Ophthalmol. Vis. Sci."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"S248","DOI":"10.1111\/j.1755-3768.2011.3125.x","article-title":"Assessment of the efficacy of cationorm in patients with moderate dry eye compared with Optive and Emustil eye drops","volume":"89","author":"Aragona","year":"2011","journal-title":"Acta Ophthalmol."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"792","DOI":"10.1016\/j.ajo.2010.10.032","article-title":"Tear Osmolarity in the Diagnosis and Management of Dry Eye Disease","volume":"151","author":"Lemp","year":"2011","journal-title":"Am. J. Ophthalmol."}],"container-title":["Medicina"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1648-9144\/59\/7\/1298\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T20:11:44Z","timestamp":1760127104000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1648-9144\/59\/7\/1298"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,7,14]]},"references-count":51,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2023,7]]}},"alternative-id":["medicina59071298"],"URL":"https:\/\/doi.org\/10.3390\/medicina59071298","relation":{},"ISSN":["1648-9144"],"issn-type":[{"value":"1648-9144","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,7,14]]}}}