dry eye dx and tx

Diabetes and Dry Eye — Is There a Connection?

BY WILLIAM TOWNSEND, OD, FAAO

Diabetes is becoming increasingly prevalent in our society. Improvements in understanding this disease, better medications, and improved methods for treating complications have increased the life expectancy of diabetics.

But as diabetics live longer, they have a higher risk for developing other related complications. The most common vision-threatening diseases associated with diabetes are cataracts, macular edema, neovascular glaucoma, macular degeneration, and dry eye syndrome. For those of us who have special interest in dry eye diseases, the logical question is, "Are diabetes and dry eye related, and if so, in what ways?"

Establishing a Link

As a general rule, Type II diabetes and dry eye disease appear to increase with age. The mechanisms that cause dry eyes are probably multiple and are still not fully understood, but autonomic dysfunction may be contributory. Fujishima et al (1996) found that administration of a systemic inhibitor of aldose reductase (the first enzyme of the sorbitol pathway) significantly improved tear dynamics. This would have potential implications in the association of diabetes and dry eye.

Manaviat et al (2008) evaluated Type II diabetics for the prevalence of dry eye and diabetic retinopathy. They reviewed the literature and found that superficial punctate keratopathy, trophic ulceration, and persistent epithelial defect were more prevalent in diabetics compared to non-diabetics; all of these conditions have been linked to dry eye. In their study of 199 subjects, 108 patients (54.3 percent) had dry eye syndrome. Increased prevalence of dry eye syndrome was significantly associated with a longer duration of diabetes.

It is worth noting that the 54.3 percent incidence of dry eye in Manaviat's work correlates very well with a study by Seifert and Strempel (1996), who found a 52.8 percent incidence of dry eye in diabetics compared to 9.3 percent incidence in non-diabetics.

Diabetes has the potential to affect any tissue in the body, but nervous tissue is especially vulnerable to diabetic-related changes. Neuropathy is a common complication and manifests as extraocular muscle paresis and as Bell's palsy, which affects the eyelids and may leads to dry eye syndrome. This represents one of several complications of diabetes that may directly affect the ocular surface.

Diabetes also impacts the ocular surface of young patients. Akinci et al (2007) compared the symptoms, signs, and results of objective tests for dry eye syndrome in 104 children with Type I diabetes and 104 age- and sex-matched controls. They found that 15.4 percent of the children with Type I diabetes had dry eye symptoms, compared to only 1.9 percent of those in the control group. Dry eye signs were detected in 7.7 percent of the children who had diabetes, versus 0.96 percent of those in the control group. Tear breakup time and Schirmer test results were significantly lower in the diabetes group compared to the control group.

Putting the Information to Use

How can we utilize this information in our practices? First, we need to add dry eye to our list of "diabetic concerns" that include retinopathy, EOM paresis, neovascular retinopathy, etc. This would also suggest that if we are not routinely screening for dry eye in our diabetic population, we should begin to do so. And in our pediatric population, we should screen for dry eye signs and symptoms in an age group that we often assume has adequate, healthy tears and minimal anterior surface disease. CLS

For references, please visit www.clspectrum.com/references.asp and click on document #162.

Dr. Townsend practices in Canyon, Texas and is an adjunct faculty member at UHCO. E-mail him at drbilltownsend@gmail.com.