Eye Disorders in Diabetes Mellitus

Saturday, August 13, 2005

Breakout Session

Speaker
M Rema, MBBS, DO, PhD

Reported by Joelle Escoffery, PhD

Patients with diabetes are twice as likely as their nondiabetic counterparts to have eye disorders. The retina, the cornea, and the lens are all susceptible to the harmful effects of hyperglycemia due to diabetes. Diabetic retinopathy (DR) is a common form of diabetic eye disease. For classification purposes, DR is divided into 2 primary subcategories: nonproliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy. NPDR is further subdivided into early, moderate, and severe NPDR, with severe NPDR being characterized by the presence of cotton wool spots. The primary types of sight-threatening DR include proliferative diabetic retinopathy (PRD) and diabetic macular edema (DME), which is caused by a thickening of the macula. Unlike NPDR, PDR is associated with new vessel formation, or neovascularization. If left untreated, PDR can result in a preretinal hemorrhage. In terms of prevalence of diabetic retinopathy, the rates vary from approximately 20% to 50%, with the prevalence rates being considerably lower among people from India.

There are a variety of tools and techniques available for the diagnosis of DR. Patients should have a retinal exam, visual acuity testing, and fundus photography. Other tests available to diagnosis and evaluate the progression of DR include optical coherence tomography (OCT) and fluorescein angiography. Management of sight-threatening DR involves treatment with laser photocoagulation. In the case of DME, focal and grid laser photocoagulation are typically used. In PDR, panretinal photocoagulation is used. In the case of a preretinal hemorrhage that does not resolve over time, a vitrectomy may be required. Baseline vision plays an important role in the success of outcomes following these procedures. A number of other eye disorders are more common among people with diabetes and hyperglycemia, including cataracts, a variety of infections, corneal disorders (eg, epithelial keratitis and neurotrophic keratitis) refractive changes (especially when glycemic control is improving or declining), glaucoma, and a variety of cranial neuropathies.

The diabetes educator can play a number of important roles associated with diabetic eye diseases. First and foremost, the diabetes educator can impress upon patients the importance of asymptomatic screening, as the likelihood of treatment success improves with early diagnosis (ie, before any changes in vision occur). Additionally, there are a number of visual aids available to help patients with low vision manage their diabetes, including adaptive devices for insulin and monitoring that include magnification, auditory, or tactile components. Finally, once a patient has visual impairment, the diabetes educator can refer the patient for psychosocial counseling, peer or group support, and can assist patients in with financial concerns associated with visual aid use.