Dry Eye in the Aging Patient

Like it or not, we’re all getting older, and not only does the aging process take a toll on our bodies, but it also affects our eyes. The number of Americans older than 65 years of age has been rising over the past 10 years and will continue to grow in the next 2 decades due to increased life expectancies and the post-World War II baby boom.¹ By 2050, it is projected that the number of people 85 years and older will triple.¹

Studies show that the prevalence of dry eye disease (DED) increases with age from the fourth to eighth decade of life and is most prevalent in women during this period.^2,3 With these numbers rising, it is expected that DED will be one of the main drivers of ophthalmic visits in the next several years.⁴

THE PRICE OF GETTING OLDER

Age-related anatomic changes, systemic conditions that require long-term management, and ocular disease are all significant risk factors for developing DED. Additionally, in my practice, older patients are more inclined to pursue refractive and oculoplastic surgeries, which predispose the ocular surface to long-term ramifications of DED.

Some of the most common anatomic alterations that can occur with age are lid laxity and meibomian gland atrophy.² Over time, stasis, inspissation, and obstruction cause decreased meibum secretion, which leads to oxidative stress and inflammation. Long term, gland atrophy and truncation ensue (Figure 1). Lid laxity can cause risk for exposure keratopathy, leading to severe vision-related problems. Another subset of patients suffer from aqueous deficient dry eye, most commonly from preexisting autoimmune conditions, such as Sjögren syndrome and rheumatoid arthritis, or from polypharmacy. These patients have a failure of the lacrimal tear mechanism that results in hyperosmolarity and the release of cytokines, which adversely affects goblet cell function (Figure 2).⁵

AGE-RELATED CHANGES

Cardiovascular disease is heavily associated with older patients, as is cancer, depression, and hormonal changes in women.³ Many of these require long-term management with oral therapies, including but not limited to antihypertensives, anti-diabetics, and antidepressants. These are some of the most common classes of drugs that have adverse drying side effects on the ocular surface.⁶

Additionally, a portion of our older patients have ocular disease, such as glaucoma, which require long-term topical management. Most mainstream therapies must be dosed chronically and contain benzalkonium chloride. Prolonged use of these medications can cause damage by destroying goblet cells and disrupting corneal epithelial tight junctions.⁷

Elderly patients are also susceptible to other age-related changes, such as cataracts, and eyelid pathologies, such as ptosis or entropion, many of which require surgery to improve patient quality of life (Figure 3). These surgeries, however, can cause neurotrophic changes. During these procedures, the corneal nerve endings, located in the basal and stromal layers that aid in regulating tear production, can be transected and damaged. Reduced corneal sensation over time leads to hyperosmolarity, ocular surface inflammation, epitheliopathy, and glandular apoptosis.⁸

Postoperative inflammation can also contribute significantly to the development of DED after surgery. Wound healing on the corneal surface is facilitated via cytokine-mediated and prostaglandin pathways, which promotes the recruitment of inflammatory mediators. These mediators instigate the production of other proinflammatory proteins, such as matrix metalloproteinase-9 (MMP-9) and substance P, and calcitonin gene-related peptide (CGRP), which promotes vasodilation and vessel permeability.⁹ It is imperative to manage any pre-existing ocular surface disease (OSD) prior to referring a patient for surgery to reduce the risk of secondary complications. If neglected, the long-term effects of OSD can be challenging to manage.

MANAGING DED

Managing DED in older patients is no different than managing the condition in other patients. I start with a complete evaluation, which includes a noninvasive analysis of tear breakup time, upper and lower meibography (see the article on meibography by Leslie E. O’Dell, OD, FAAO), InflammaDry (Quidel), Schirmer testing, fluorescein and lissamine green staining, and traditional tear breakup time measured using a slit lamp. Meibomian gland evaluation is performed with gentle palpation along the lid margins or with a Meibomian Gland Evaluator (Johnson & Johnson Vision), which approximates the pressure of a deliberate blink. I establish a comprehensive treatment plan based on the test results and schedule a follow-up visit, generally 1 to 3 months out, depending on the severity of the patient’s DED.

The most basic tools needed to manage DED include:

• Vital dyes; it’s good practice to stain every patient, regardless of age or symptoms. It is astounding to see what is revealed with this simple step, and the clinician becomes much more astute in diagnosing and monitoring any new or preexisting ocular surface conditions.
• A fundus camera, which can act as an anterior segment camera
• A slit lamp
• A transilluminator, which can be used to aid in evaluating meibomian gland structure and any incomplete lid closure by way of the Korb-Blackie light test.¹⁰

THE IMPORTANCE OF A TREATMENT REGIMEN

In my practice, every DED treatment regimen begins with lid hygiene. Blephadex Eyelid Wipes or Eyelid Foam (Lunovus) works well for mild blepharitis, and Ocusoft Lid Scrub (Ocusoft) works for moderate to severe cases. Any signs of saponification can be addressed with Avenova Lid & Lash Solution (NovaBay Pharmaceuticals) due to its excellent antibacterial properties via the hypochlorous acid formula. Moderate to severe ocular surface staining or severe symptomatology may be combated with a short pulse of topical steroids in combination with OTC lubricants. Once staining is eradicated, topical immunomodulators are efficacious in managing long-term inflammation. Viscous gels or ointments may also be necessary for additional relief.

Lipid-Deficient Patients

A variety of oil-based, preservative-free tears (eg, Refresh Optive Mega-3, Allergan; Retaine MGD, Ocusoft) work well to maintain homeostasis of the tear film and provide significant symptomatic relief. Recommending adjunctive therapies for mild signs of meibomian gland dysfunction (MGD), such as warm compresses and blinking exercises, is especially beneficial. Moderate to severe levels of MGD benefit greatly from thermal pulsation treatment, such as that achieved with the TearScience LipiFlow Thermal Pulsation System (Johnson & Johnson Vision) and meibomian gland expression. In the past several months, I have seen tremendous success with 0.03 mg varenicline solution (Tyrvaya, Oyster Point Pharma) as a first or second-line therapeutic (Figure 4). Its mechanism of action involves stimulating increased basal tear production via the parasympathetic pathway by activating the trigeminal nerve.¹¹

Aqueous-Deficient Patients

Severely aqueous-deficient patients who do not respond to traditional methods, autologous serum drops, or amniotic membranes are particularly effective in stabilizing the tear film via growth factors, antioxidants, proteins, and lipids.¹² After improvement is achieved, the addition of punctal plugs may maintain control of the disease. Scleral lenses are also a viable option for patients with severely dry eyes with corneal or conjunctival irregularities or those who have poor blink function. In addition, omega supplements are complementary to treatment regimens due to their antiinflammatory properties and have been found to improve symptomatology scores via the Ocular Surface Disease Index among patients with DED.¹³

BE PREPARED

As the greater proportion of our population ages in the coming years, the need to manage DED will increase dramatically. Understanding the mechanism, risk factors, and challenges that the aging patient faces will prompt treatment intervention and prevent ocular surface complications. Embracing DED in our aging population will ensure patients an enhanced, long-lasting quality of life.