In the United States, diabetes-related retinopathy (DRR) is the number one cause of blindness for working age adults; however, eye care experts estimate that blindness resulting from DRR could be reduced by 90% (Vashist et al., 2011). Therefore, it is critical to understand how DRR affects eyesight as well as how self-management behaviors can prevent vision loss from DRR.
Chronic hyperglycemia and hypertension can initiate a cascade of events impacting the retina, eventually causing vision loss. Nonproliferative retinopathy causes capillaries to form small bulges called microaneurisms. As the process continues, these microaneurysms and other small vessels may begin to leak or rupture causing tissue edema. The resulting loss of oxygen and nutrients to the neural elements of the retina triggers ischemia, which may worsen if left untreated. Nonproliferative retinopathy has no subjective symptoms, is generally reversible and nonsight threatening. Proliferative retinopathy is characterized by the formation of new vessels (neovascularization) to restore vascular function to the ischemic retina. Unfortunately, these vessels are fragile and prone to rupture, which may cause hemorrhages within the eye. Retinal scaring, adhesions, and detachments can ensue. Proliferative retinopathy and loss of vision from nerve damage is permanent. Macular edema (ME) is a special case with fluid leakage occurring within the macular or foveal region of the eye (Figure 1). It is estimated that 24% of people with diabetes 40 years or older have nonproliferative or proliferative retinopathy and 3.8% have ME (Varma et al., 2014). The incidence of ME is less for people diagnosed with type 2 diabetes; however, it is the major contributor of vision loss within the 40 years or older age group (Lee et al., 2015).
Saving vision starts with good diabetes self-management. Establishing optimal blood glucose and blood pressure levels will reduce the incidence of DRR complications. A sentinel study established that for type 2 diabetes, each 1% reduction in HA1c reduced the risk of microvascular complications by 37% (Stratton et al., 2000), and every 10 mm reduction in blood pressure reduced microvascular complications by 13% (Adler et al., 2000). External or extrinsic barriers to eye care might include inadequate finances, lack of family and community support systems, and limited access to eye care.
Education and communication is important. It is important to educate people with diabetes (PWD) on how diabetes affects vision. Less than 60% of PWD currently follow the American Diabetes Association (ADA) recommendations for an annual eye examination for DRR screening (Murchison et al., 2017). In a small survey, 75% of PWD incorrectly believed that DRR was accompanied with early warning signs (Wagner et al., 2008). Lack of communication also affects physicians. In one study, only 45% of adults 40 years or older with ME reported being told by a physician that diabetes had affected their eyes or that they had retinopathy (Bressler et al., 2014).
Be knowledgeable of ADA standards of care. The ADA 2018 Standards of Care recommend that PWD have a comprehensive dilated eye examination (CVE) within 5 years for type 1 and on diagnosis of diabetes for type 2. Afterward, exam intervals may be adjusted as indicated by the presence and severity of DRR. In the case of pregnancy, examinations should take place before or within the first trimester for type 1 or type 2 diabetes and be monitored each trimester until 1 year postpartum depending on the presence of DRR (ADA, 2013).
Know the risk factors for DRR. The Retina Risk website (http://www.retinarisk.com) may help providers initiate a discussion about DRR with their patients. Using various factors associated with DRR (e.g., blood pressure, A1c, time since diagnosis), an algorithm predicts the potential of sight threatening retinopathy and provides education about modifiable risk factors for better self-management. The website is free for 30 days for PWD who register at the site.
There are certain PWD who overlook the need for a CVE. Murchison et al. identified several factors that may help identify PWD at risk for vision loss from DRR:
* PWD with normal vision; these individuals may mistakenly think that if there are no subjective signs, they do not have DRR.
* Older patients with severe DRR; these individuals may not be aware of the potential for vision loss or may not notice a vision decrease in one eye.
* PWD with mild DRR and no history of other eye diseases; because of no loss of vision these individuals do not appreciate the need for a CVE.
* PWD who self-report no eye care history or information about A1c or BG readings.
* PWD who smoke.
Collaborate with local eye care practitioners. Establish contacts and have a list of eye care providers or local healthcare centers in your area that can provide a CVE. Ask questions about vision problems PWD may be experiencing from the contacts you have established. Most eye care offices will be happy to provide information.
Use an eye chart. Decreases in visual acuity are an indication that something is changing. PWD are also 40% and 60% more likely to develop glaucoma and cataracts, respectively (ADA, 2013). The time invested in learning the use of a simple eye chart could help save vision.
This YouTube video is a helpful start https://youtu.be/kMwy06mAV5U. General questions about DRR, education or interventions can be found on this website: http://www.diabetesrelatedretinoathy.com
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