discovering dry eye

Aging, Hormones and Dry Eye

BY KELLY KINNEY NICHOLS, OD, MS
SEPTEMEBER 1999

Bifocal contact lens and monovision patients may develop tolerance issues with their lenses, which can be irritating to them as well as to you. So what do you do when you encounter elderly patients suffering from dry eye?

As your patients age, you can monitor the changes in their tear composition and stability with clinical diagnostic tests. Recent research has shown that there is a decrease in total tear volume and tear production, and an increase in tear osmolarity with increasing age. These results are consistent with other studies involving tear production and osmolarity and indicate that film function declines throughout life.

In the past, there has also been a debate regarding the affect of hormones on the eye. Many clinicians believe that post-menopausal women suffer more frequently from dry eye than younger women. While the etiology of dry eye in post-menopausal women is unclear, the influence of hormones is strongly suspected to play a role.

What the Past Has Taught Us

Research has shown that androgens, estrogens and progestins may have a significant influence on the structure and function of many ocular tissues, including the lacrimal gland and anterior surface of the eye.

While the conjunctiva is reported to be sensitive to estrogen in menstruating and pregnant women (cyclic maturation of conjunctival cells), the presence of estrogen receptors on the anterior surface of the eye and the lacrimal gland has not yet been established. In contrast, the lacrimal gland does show receptors for androgen and prolactin, both of which have been shown to affect tear production. In addition, it is thought that estrogen and glucocorticoids have an indirect regulatory role in maintaining tear film. Topical hormones have been used experimentally to treat dry eye. Estrogen was topically applied in a gel formulation to the ocular surface in women with post-menopausal dry eye symptoms, and a few clinical diagnostic tests showed an improvement in subjective symptoms (Akramian, 1998).

Findings with a Placebo Group

In a similar study utilizing a placebo group (Sator, 1998), topical 17B-oestradiol ophthalmic drops were applied to the ocular surface in the treatment group. Both the treatment group and the placebo group initiated hormone replacement therapy at the time of enrollment. The authors of this study found an improvement in subjective symptoms, tear production and tear stability. They concluded that the topical drops were successful in treating dry eye and that the blood-eye barrier prevented systemic estrogens from acting on the conjunctiva.

Hormone Replacement Therapy

In contrast to the study by Sator, et al., a recent study by Vavilis (1995) found a statistically significant difference in the cytological maturation of conjunctival cells in patients on hormone replacement therapy versus those not receiving the therapy. This finding indicates that systemic HRT does play a role in maintaining the ocular surface. In addition, estrogen may play a large role in maintaining the patency of the meibomian glands and the secretion of the oil layer of the tear film. While this research is still inconclusive, further research in this area may elucidate changes in lens comfort related to tear film stability.

Researchers are diligently trying to determine the effect of hormones on patients with dry eye with the hopes of identifying a "magic drop" that will eliminate the effects of age on the anterior surface of the eye. As a clinician, I look forward to this "potion" which will sooth both patient and doctor dry eye "irritation."

Dr. Nichols is a graduate student at The Ohio State University College of Optometry in the area of dry eye research.