*Corresponding author: Stella Ngozi Onwubiko, Department of Ophthalmology, University of Nigeria Teaching Hospital, PMB 01129, Ituku-Ozalla, Enugu, Nige- ria, Tel: +234 8037434803; E-mail: srstellao16@yahoo.com; stella.onwubiko@ unn.edu.ng Citation: Onwubiko SN, Nwachukwu NZ, Eze BI (2019) Seasonal Variation in Tear Secretion and Tear-Film Stability among Adults in Enugu, Nigeria: A Longitudinal Study. J Ophthalmic Clin Res 6: 054 Received: July 15, 2019; Accepted: July 30, 2019; Published: August 06, 2019 Copyright: © 2019 Onwubiko SN, et al. This is an open-access article distribut- ed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the orig- inal author and source are credited. Introduction It has been documented that the secretion and function of the pre-corneal tear-flm is associated with both intrinsic and extrin- sic factors, ranging from advancing age [1-4], female gender [1-3], weather and environmental factors such as humidity, temperature and wind [4-6], use of some medications as anti-depressant and anti-his- tamine [7], and activities that promote infrequent blinking such as working on a computer [8], among others. These factors are quite challenging in the diagnosis and manage- ment of Dry Eye Disease, (DED), a clinical condition resulting from deranged tear-flm. DED is of public health importance, a chronic dis- ease of the ocular surface with bothersome symptoms, necessitating frequent hospital visits and use of eye lubricants, which greatly im- pacts on patients’ quality of life [9-11]. Understanding the infuence of these extrinsic factors on the secre- tion and function of the pre-corneal tear-flm would be of great help to the clinician to proffer differing management protocols, especially by modifying them to suit the individual patient with DED or other ocular surface disease. Fewer studies have investigated the seasonal infuence on the tear- flm and invariably on DED [5,6]. In the US, symptoms of DED were exacerbated in the dry, cold, and windy environment of winter among patients from the Greater Boston Area [6], and in Maimi [5], during winter and spring. In Enugu, DED is of public health importance, with a prevalence of 19.2% [3]. To the best knowledge of the researchers, no similar study has been done. This study therefore sought to investigate the seasonal infuence on the tear-flm secretion and function and its pos- sible association with the anthropometric characteristics of healthy subjects. The fndings would assist the clinicians to make informed decision on the management of ocular surface diseases in the study area and elsewhere with similar settings. Methods Background Enugu is the capital of Enugu State, one of the 36 states of the Federal Republic of Nigeria. It is one of the 5 states that make up the south-east geo-political zone. It is sub-divided into 17 Local Govern- ment Areas (LGAs), of these, Enugu-North, Enugu-East, and Enu- gu-South LGAs form Enugu urban. Enugu is located in the tropical rainforest climatic region, with two seasons of the year, rainy (May to October) and dry (November to April) seasons. The population is predominantly Ibos, with civil service, farming and trading as their major occupations. Onwubiko SN, et al., J Ophthalmic Clin Res 2019, 6: 054 DOI: 10.24966/OCR-8887/100054 HSOA Journal of Ophthalmology & Clinical Research Research Article Stella Ngozi Onwubiko*, Nkiru Zuadae Nwachukwu and Boniface Ikenna Eze Department of Ophthalmology, University of Nigeria Teaching Hospital, Enugu, Nigeria Seasonal Variation in Tear Secretion and Tear-Film Stability among Adults in Enugu, Nigeria: A Longitudinal Study Abstract Aim: To investigate the variation in tear-flm secretion and function between rainy and dry seasons among healthy adults in Enugu, Ni- geria. Methods: This was a population-based, longitudinal study involving a cohort of 31 healthy adult Nigerians residing in Enugu in 2018. The objective tests for tear secretion (Schimer’s test) and function (tear- flm break-up time, TBUT) were conducted on the 62 eyes of the participants in January and July, the peaks of dry (D) and rainy (R) seasons, after obtaining their socio-demographic information. Their palpebral fssure height (PFH) and length, (PFL) were also obtained. Data was analysed using SPSS version 21. The level of signifcance was at p- < 0.05. Results: The participants comprised of more females, 20 (64.5%) than males, with a mean age of 33.7 ± 9.6 SD years. They were mainly civil servants with tertiary education.The mean TBUT -R was 30.0 ±18.3 seconds and D, 15.6 ± 9.5. The mean Schirmer’s test-R was 25.2 ± 10.1 mm and D, 22.1 ± 11.2 mm. There was signifcant difference between these means in rainy and dry seasons. (p =0.000 TBUT, p = 0.04 Schirmer’s test). When TBUT and Schirmer’s test in both seasons were correlated with PFH and PFL, only TBUT -R and PFH showed a signifcantly positive correlation (r = 0.54, p= 0.002). Conclusion: A signifcant seasonal variation in tear-flm secretion and function exists among adults in Enugu. The higher the PFH, the less the break-up of the tear-flm during rainy season. These fndings have great implications in the management of dry eyes. The use of therapeutic lubricant gels to prolong the TBUT time in dry seasons may therefore be preferred. Keywords: Dry eyes; Enugu; Nigeria; Schimer’s test; Seasonal vari- ation; TBUT