Saving Sight in Your Patients with Diabetes: What You Might Be Missing

Decoding the Differences Between Ophthalmologists and Optometrists

Ophthalmologists are medical doctors who complete about 5 years of postgraduate training in the breadth of ocular disorders. They can diagnose and appropriately treat ocular conditions both medically and surgically. A retina specialist has subspecialized and received additional training in retinal diseases and surgery, as well as in retinal imaging, which is used to detect, diagnose, and monitor diabetic eye disease. Therefore, both ophthalmologists and retina specialists have the necessary knowledge to provide direct medical and surgical care to manage the manifestations of diabetic eye disease.

Optometrists are eye doctors who are also trained in detecting and diagnosing diabetic retinopathy (DR). Because of today’s advanced technology, such as optical coherence tomography (OCT), they are equipped to recognize and diagnose diabetic macular edema (DME), a vision-threatening complication (VTC) seen as retinal swelling that may occur at any stage of DR (Figure 1). In addition, they manage patients with mild and moderate nonproliferative stages of DR and those with a lower risk of progression to the advanced or proliferative stage (Figure 2). Patients with a higher risk of progression to proliferative DR or DME are referred to a retina specialist for monitoring and possible treatment (Figure 2).

Figure 1. OCT improves detection of DME.

Figure 2. Stages of DR: mild nonproliferative (top left), mild/moderate nonproliferative (top right), severe nonproliferative (bottom left), and proliferative (bottom right).

Remote Imaging as a Screening Tool
Unfortunately, some patients with diabetes do not understand the importance of an eye examination, particularly when they think that their vision is good and has not been affected. Advancements in remote imaging have increased patient access to eye care, potentially preserving more patients’ vision. In remote imaging, retinal images are captured in the office of an endocrinologist or primary care physician and then sent to a reading center for an analysis of DR. 

Loss of Vision: Diabetic Macular Edema and Proliferative Diabetic Retinopathy
Patients with diabetes lose vision from DME and/or proliferative DR. DME negatively affects central vision, and its most severe form can lead to legal blindness. Review this animation to see the retinal changes that can result from diabetes. Fortunately, visual outcomes for many patients with DME have drastically improved with the recent availability of biologic agents, specifically anti-vascular endothelial growth factors (anti-VEGFs), which are delivered at repeated intervals via intravitreal injections by an ophthalmologist or retina specialist. Importantly, fewer than 15% of patients with DME receiving anti-VEGF therapy continue to lose vision,¹ and 50% experience significant vision recovery.² However, the final vision outcome is affected by the level of presenting visual acuity, underscoring the importance of early detection of disease. Of patients who present with mild vision impairment (defined as a visual acuity of 20/40 or better) from DME and receive treatment with anti-VEGF therapy, 95% maintain a visual acuity of 20/40 or better (Figure 3).³ This acuity is the level of vision necessary for daily living activities, such as driving and reading. In contrast, only 75% of patients who present with moderate vision impairment (defined as a visual acuity worse than 20/40) and receive anti-VEGF therapy maintain 20/40 or better vision (Figure 3).³ Therefore, when DME is diagnosed early at the level of mild vision impairment, anti-VEGF therapy can maintain the best level of vision.

Figure 3. Presenting acuity affects visual outcome.

Proliferative DR develops in response to hyperglycemia that increases VEGF release, leading to neovascularization on the optic nerve and elsewhere in the retina. Neovascularization can lead to absolute blindness or nonambulatory vision. Fortunately, 2 main treatments are available to limit the blinding complications of proliferative DR. Panretinal photocoagulation (PRP) or laser treatment was the mainstay treatment of proliferative DR for decades until the introduction of anti-VEGF therapy, which changed the treatment landscape because of its effectiveness with fewer side effects.

Preventing Proliferative DR: Protocol W and PANORAMA
Two pivotal prospective, randomized clinical trials were designed to address whether anti-VEGF therapy slowed or prevented proliferative DR and DME in patients with nonproliferative DR.^4,5 Both PANORAMA and Protocol W demonstrated that anti-VEGF therapy improved the severity level of nonproliferative DR through 2 years (Figure 4, 5).^4,5 Specifically in PANORAMA, significantly fewer eyes with moderately severe to severe nonproliferative DR receiving aflibercept every 16 weeks (Q16W) or every 8 weeks (Q8W) developed VTCs (Figure 4) and/or center-involved DME (16.3% Q16W and 18.7% Q8W) than eyes receiving sham (50.4%; P < 0.001 for both).⁴ In Protocol W, eyes with moderate to severe nonproliferative DR receiving aflibercept developed significantly less proliferative DR (13.5% aflibercept vs 33.2% sham) or center-involved DME (4.1% aflibercept vs 14.8% sham) (Figure 5).⁵ However, despite an improvement in anatomic outcomes, patients with nonproliferative DR who received anti-VEGF therapy (-0.9 letters) did not have a significant improvement in their visual acuity from baseline to 2 years compared with those who received sham injections (-2.0 letters; P = 0.47).⁵ Future research from Protocol W’s 4-year data will analyze visual acuity outcomes over a longer term.⁵ For now, the takeaway message of these trials for clinicians is that certain patients with nonproliferative DR may benefit from early, preventative treatment with anti-VEGF therapy.

Figure 4. Anti-VEGF therapy reduced the risk of VTCs in moderate to severe nonproliferative DR in PANORAMA.⁴

Figure 5. Anti-VEGF therapy reduced the risk of VTCs in moderate to severe nonproliferative DR but did not improve visual acuity in Protocol W.⁵ CI-DME, center-involved diabetic macular edema; PDR, proliferative diabetic retinopathy; y, year.

Key Messages in Patient Education
Early detection of DR is essential to achieve the best vision outcomes. Patients must take an active role in their eye care, regardless of how busy their lives may be. Healthcare providers (HCPs) can effectively educate patients with diabetes by using educational materials that facilitate patient understanding of diabetic eye disease and diabetic eye examinations. Key messages to deliver in patient education are that DR may be 1) “silent,” meaning it may be present without symptoms or visual changes, 2) DR can be detected with an eye screening or examination in its early stage (giving the best chance of preserving vision and preventing vision loss), 3) continued care with all HCPs is important, and 4) systemic well-being can prevent vision loss and damage to other organs. Systemic care includes controlling glucose levels, blood pressure, and cholesterol and stopping smoking. Another key point to discuss with patients is the goal of the diabetic eye examination, which is to assess for any leaking or bleeding of the retinal blood vessels. Patients must also understand that proliferative DR is a potential complication throughout their journey with diabetes, and they must therefore continue to receive eye care at regular intervals.

During a patient’s eye examination, ophthalmologists and optometrists incorporate viewable images as educational tools. For example, colored images obtained on fundus imaging and OCT illustrate DR, seen as microaneurysms and retinal hemorrhages, and illustrate DME, seen as thickening or swelling of the retina (Figures 1, 2). These images help patients appreciate the ocular effects of diabetes. In addition, ophthalmologists and optometrists may display patients’ images on large monitors in the exam room and compare them to those from previous exams. These images can help motivate patients when they see the improvement in their DR as a response to treatment or better systemic care—or when they see worsening of their DR.

Save Sight Key Takeaways
Excellent care for patients with diabetes requires a team of HCPs, including endocrinologists, primary care physicians, and eye care providers. Comprehensive education is key for patients to understand the importance of overall health and eye care throughout their journey. The entire team of HCPs can emphasize the components of health—blood sugar and blood pressure control, exercise, a healthy diet, and no smoking—to prevent damage to organs. HCPs should also emphasize preventative eye care to patients by recommending examinations that can detect DR early. In addition, HCPs should appropriately refer patients with DR to a retina specialist for potential vision-saving treatment. Anti-VEGF therapy can greatly limit vision impairment when initiated in a timely manner. Through patient education and timely referrals, HCPs can work together to improve the vision outcomes of many patients with diabetes.

References

1. Campbell J, Cole AL, Almony A, et al. Real world vision outcomes in DME treated with anti-VEGF injections - an analysis of EMR data from a large health system. Invest Ophthalmol Vis Sci. 2014;55(13):3065.
2. Bressler NM, Chang TS, Suñer IJ, et al. Vision-related function after ranibizumab treatment by better- or worse-seeing eye: clinical trial results from MARINA and ANCHOR. Ophthalmology. 2010;117(4):747-56.e4. 
3. Wells JA, Glassman AR, Ayala AR, et al; Diabetic Retinopathy Clinical Research Network. Aflibercept, bevacizumab, or ranibizumab for diabetic macular edema: two-year results from a comparative effectiveness randomized clinical trial. Ophthalmology. 2016;123(6):1351-1359.
4. Brown DM, Wykoff CC, Boyer D, et al. Evaluation of intravitreal aflibercept for the treatment of severe nonproliferative diabetic retinopathy: results from the PANORAMA randomized clinical trial. JAMA Ophthalmol. 2021;139(9):946-955. 
5. Maturi RK, Glassman AR, Josic K, et al. Effect of intravitreous anti-vascular endothelial growth factor vs sham treatment for prevention of vision-threatening complications of diabetic retinopathy: the Protocol W randomized clinical trial. JAMA Ophthalmol. 2021;139(7):701-712.