European Journal of Cardiovascular Medicine

The tear film which is approximately 3μm thick and 3μl in volume is a unique fluid layer covering the outer most mucosal surface of the eyes. Actually it is the interface between ocularsurface of the eye and the environment.^[1] This transparent film has a mucin or aqueous phase with decreasing in the mucin content towards superficial layer of lipid.These layers of fluid contain distinct biochemical components which perform distinct functions.^[2] Lipid layer of the tear film is about 50 to 100 nm thin and contains different lipids like cholesterol and wax esters which make it bulk. Some other lipids like ω-hydroxyfattyacids as well as phospholipids interact with the aqueous layer.^[3] Most of these lipids are secreted from the meibomian glands present in eye lids. The lipid layer performs the most vital function for eye i.e.  Preventing evaporation of the tear from ocular surface.^[4] Dry eye is a heterogeneous group disorder characterized by insufficient lubrication of the ocular surface. Dry eye, a potentially harmful and chronic condition which limits the activity as well as often causes blindness.^[5] Dry eye syndrome in postmenopausal women is devastating for patients, researchers as well as clinicians due to scarceness of successful treatment modalities and problematic assessing efficacy of treatment plans. Therefore quick detection of problems and successful treatment is essential. ^[6] Dry eye syndrome or keratoconjunctivitis sicca is a disorder of tear film either due to deficiency of tear or excessive evaporation of tear which causes damage to the inter-palpebral ocular surface.^[7] Dry eye is a multifactorial disorder characterized by loss of homeostasis in the tear film along with accompanied ocular symptoms. The etiology behind this may be the instability of the tear film, ocular surface inflammation, ocular surface damage as well as sensory abnormalities of eye. Meibomian gland dysfunction sometimes leading to a condition known as evaporative dry eye, characterized by secretion of normal tear volume but there is increased rate of tear evaporation.^[8] Therefore reduced oestrogen secretion after menopause may be the cause of increasing the chances of dry eye syndrome in post-menopausal women. Estrogen deficiency may be the factor that causes alteration of sebaceous gland; hence there is chance of destabilization of tear film due associated with meibomian gland dysfunction. In older age group low androgen levelis also associated with dry eye consistently.With increasing age there is more chance of meibomian gland dropout, especially above 50 years of age, which further leading to increasing the chances of meibomian gland dysfunction.^[9] Dry eye occurs due to inadequate tear production or excess evaporation tear, hence is classified into aqueous production deficient dry eye and evaporative dry eye.^[10,11] Therefore this study was planned to assess the prevalence of dry eye in postmenopausal women.

This cross-sectional study was conducted in the department of Physiology in collaboration with Ophthalmology, in a tertiary health care institute in eastern India. This study included 183 postmenopausal women attending ophthalmology OPD. For selection of subjects consecutive sampling method was preferred. The study was completed in between January 2022 to December 2023. The study was approved by Institutional Ethics Committee of the institute where study was done. All subjects signed the informed written consent form.

Inclusion criteria: All women in the natural menopause age attending ophthalmology OPD were included in this study.

Exclusion criteria: Women having pre-existing dry eye, ocular surface disorder, history of ocular trauma, history of ocular surgery, patients on topical medication for prolonged period, contact lens users and any systemic disease associated generalized dryness were excluded from the study.

Patient details i.e. name of patient, age, menopausal age, occupation, area of dwelling (rural/urban) was recorded. Ocular symptoms like ocular fatigue, foreign body sensation, temporary blurred vision (improved on blinking), redness, dry sensation, discomfort, watering eye, itching and burning sensation were noted. Laterality of symptoms was noted. Objective tests like visual acuity, slit lamp examination, Schirmer’s test and tear film breakup time were done.

Diagnostic procedure: Schirmer’s test is a standard procedure to diagnose dry eye. All the subjects were screened by Schirmer’s test as a screening test for dry eye. Schirmer’s basal secretion test was done in following manner: one drop of 0.5% proparacaine hydrochloride was instilled into the eyes as topical anaesthesia and the fornix of conjunctiva was dried with the help of a cotton tip applicator. After a 2-min waiting period, 5 mm wide and 35 mm long Standard Whatman No. 41 filter paper strip was folded 5 mm from one end and placed between lower eyelid and the globe. Proper care was taken to avoid touching the cornea at the junction between middle and lateral third of the eyelid. The patients were allowed to blink normally as usual. After 5 min wetting was measured in millimetres.

Statistical analysis: Prevalence of dry eye was estimated. The Schirmer`s test values was compared between the groups. The data was analyzed using the Chi-square test. P value less than 0.05 was considered to be significant.

Fig 1 depicts the dry eye prevalence. Among 183 study subjects 97 were having dry eye which accounts 53% of post menopausal women.

Fig 2 depicts dry eye frequency distribution in different age group. In age group 51 – 60 years 70 patients were examined, among them 30 (42.8%) were having dry eye. In age group 61 – 70 years 55 patients were examined, among them 28 (50.9%) were having dry eye. In age group more than 70 years 58 patients were examined, among them 39 (67.2%) were having dry eye.

Table 1 depicts prevalence of dry eye with or without symptoms. Among 183 study participants 97 were having dry eye. Out of 97 dry eye 54 (55.6%) were symptomatic and 43 (44.4%) were asymptomatic. This distribution showed a significant variation at p value 0.0009.  

Table 2 depicts distribution of study population according to Schirmer’s test. Among all dry eye mild, moderate and severe form of dry eye were 50.5%, 38.1%, and 11.4% respectively.

In this study we found 53% of subjects were having dry eye. This study observed that the prevalence of dry eye was increased with increasing the age of patients. It was found that some dry eye patients had symptoms and some were without symptoms. Among all dry eye patients majority were mild form followed by moderate and then severe.

Researchers have reported that females are more prone to suffer from dry eye in comparison to males due to the effect of female sex hormones on ocular surface, meibomian glands and lacrimal glands.^[12] Previous researches have shown that females are a risk factor in developing dry eye and the prevalence varies from 12% to 22%.^[13] This study observed that the prevalence of dry eye increasing with the age. Prevalence rate of dry eye in the postmenopausal women more than 70 years was more in comparison to lower age group. This result is similar to the previous study in which the researchers reported that prevalence of dry eye is in increasing trend with age.^[12]

The pathophysiology behind aqueous tear deficiency based on the Sjogren syndrome, inflammation or disease of lacrimal gland and systemic drugs like beta blocker, antihistamines, diuretics, decongestants etc.^[14] In evaporative dry eye there is excessive evaporation of tear and the lipid layer of tear film is deficient. Here the tear production quantity is normal but the evaporation of tear is increased due to quality of tear.^[15] Meibomian glands present in the eyelid secretes lipid which add to the composition of tear film and reduces evaporation of tear. Thus its dysfunction contributes to change in composition of tear film and more evaporation of tear occurs, leading to evaporative dry eye.^[15] Lacrimal gland and meibomian gland expressed the receptors for androgen and estrogens. Undoubtly decreased circulating level of sex hormones at menopause probably hampers the functional and secretory status of lacrimal gland.^[16,17] Further it is emphasized that specifically oestrogen deficiency modulate inflammatory process which underlies the mechanism of dry eye.^[17] Normal value of osmolarity of tear film is about 300 mOsm/L and hyperosmolarity is the hallmark of dry eye disease which varies according to the severity.^[18] Hyperosmolarity tear film directly or indirectly may damage the ocular surface because of neurosensory abnormality of ocular surface, instability of tear film, inflammation.^[19] Inflammatory mediators involved in this process are interleukin 1, interleukin 6, alarmin, cytokines and tumour necrosis factor.^[20]            

Strength and Limitations                                                                                                                                       

This study will help the clinicians to evaluate the post menopausal women attending ophthalmology OPD and proper preventive measures can be taken for the patients. This study could have been scientifically more authentic if we could include a more number of study participants. At the same time we could not estimate the serum level of female sex hormones.  

Prevalence of dry eye disease was increased with increasing the age in postmenopausal women. The hormonal changes in the age group of menopause are the possible cause of dry eye. Awareness among postmenopausal women about dry is essential to prevent further complications. Screening of all postmenopausal women for dry eye should be mandatory.

Funding – Nil

Conflicts of Interest – No conflicts of interest

Acknowledgement – The authors are very much thankful to the study participants without whom this study could not be accomplished.

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