The Truth about Diabetic Retinopathy

 

photo from the medical futurist
photo from the medical futurist

Diabetes mellitus (DM) is a major medical problem throughout the world. Diabetes causes an array of long-term systemic complications that have considerable impact on the patient as well as society, as the disease typically affects individuals in their most productive years. An increasing prevalence of diabetes is occurring throughout the world. 

Diabetes involves changes in diet, and must avoid higher fat intake, sedentary lifestyle changes, and patients must increase physical activity and to become more active. Patients with diabetes often develop ophthalmic complications, such as corneal abnormalities, glaucoma, iris neovascularization, cataracts, and neuropathies. The most common and potentially most blinding of these complications, however, is diabetic retinopathy.

It is one of the leading causes of new blindness in persons aged 25-74 years of age, along with cataract and glaucoma. There’s a high prevalence of diabetic retinopathy in the country. The exact mechanism by which diabetes causes retinopathy remains unclear, but several theories have been postulated to explain the typical course and history of the disease.

Unfortunately, with diabetic retinopathy , patients during its early stage are generally asymptomatic, but in more advanced stages of the disease patients may experience symptoms that include floaters, distortion, and/or blurred vision. Microaneurysms are the earliest clinical sign of diabetic retinopathy.

Workup for diabetic retinopathy includes fasting glucose and hemoglobin A1c measurements.

Signs of diabetic retinopathy include the following:

  • Microaneurysms: The earliest clinical sign of diabetic retinopathy; these occur secondary to capillary wall outpouching due to pericyte loss; they appear as small, red dots in the superficial retinal layers
  • Dot and blot hemorrhages: Appear similar to microaneurysms if they are small; they occur as microaneurysms rupture in the deeper layers of the retina, such as the inner nuclear and outer plexiform layers
  • Flame-shaped hemorrhages: Splinter hemorrhages that occur in the more superficial nerve fiber layer
  • Retinal edema and hard exudates: Caused by the breakdown of the blood-retina barrier, allowing leakage of serum proteins, lipids, and protein from the vessels
  • Cotton-wool spots: Nerve fiber layer infarctions from occlusion of precapillary arterioles; they are frequently bordered by microaneurysms and vascular hyperpermeability
  • Venous loops and venous beading: Frequently occur adjacent to areas of nonperfusion; they reflect increasing retinal ischemia, and their occurrence is the most significant predictor of progression to proliferative diabetic retinopathy (PDR).
  • Intraretinal microvascular abnormalities: Remodeled capillary beds without proliferative changes; can usually be found on the borders of the nonperfused retina
  • Macular edema: Leading cause of visual impairment in patients with diabetes

Nonproliferative diabetic retinopathy

  • Mild: Indicated by the presence of at least 1 microaneurysm
  • Moderate: Includes the presence of hemorrhages, microaneurysms, and hard exudates.
  • Characterized by hemorrhages and microaneurysms

Proliferative diabetic retinopathy

  • Neovascularization: Hallmark of PDR
  • Preretinal hemorrhages: Appear as pockets of blood within the potential space between the retina and the posterior hyaloid face; as blood pools within this space, the hemorrhages may appear boat shaped
  • Hemorrhage into the vitreous: May appear as a diffuse haze or as clumps of blood clots within the gel
  • Fibrovascular tissue proliferation: Usually seen associated with the neovascular complex; may appear avascular when the vessels have already regressed
  • Traction retinal detachments: Usually appear tented up, immobile, and concave
  • Macular edema

Diagnosis

Laboratory studies of HbA1c levels are important in the long-term follow-up care of patients with diabetes and diabetic retinopathy.

 Imaging studies used in the diagnosis of diabetic retinopathy include the following:
  • Fluorescein angiography: Microaneurysms appear as pinpoint, hyperfluorescent lesions in early phases of the angiogram and typically leak in the later phases of the test
  • Optical coherence tomography scanning: Administered to determine the thickness of the retina and the presence of swelling within the retina, as well as vitreomacular traction
  • B-scan ultrasonography

‘The sad news is diabetic retinopathy can cause blindness and is irreversible.”

Diabetes interferes with the body’s ability to use and store sugar (glucose). The disease is characterized by too much sugar in the blood, which can cause damage throughout the body, including the eyes.

Over time, diabetes damages the blood vessels in the retina. Diabetic retinopathy occurs when these tiny blood vessels leak blood and other fluids. This causes the retinal tissue to swell, resulting in cloudy or blurred vision. The condition usually affects both eyes. The longer a person has diabetes, the more likely they will develop diabetic retinopathy. If left untreated, diabetic retinopathy can cause blindness.

Treatment/Management

Pharmacologic therapy

  • Triamcinolone: Administered intravitreally; corticosteroid used in the treatment of diabetic macular edema
  • Bevacizumab: Administered intravitreally; monoclonal antibody that can help to reduce diabetic macular edema and neovascularization of the disc or retina
  • Ranibizumab: Administered intravitreally; monoclonal antibody that can help to reduce diabetic macular edema and neovascularization of the disc or retina
 Glucose control
 Endocrinologists and diabetes specialists found that intensive glucose control in patients with type 1 diabetes (previously called insulin-dependent diabetes mellitus [IDDM]) decreased the incidence and progression of diabetic retinopathy.  It may be logical to assume that the same principles apply in type 2 diabetes (previously called non-insulin-dependent diabetes mellitus [NIDDM]).
Laser photocoagulation
This involves directing a high-focused beam of light energy to create a coagulative response in the target tissue. In nonproliferative diabetic retinopathy (NPDR), laser photocoagulation is indicated in the treatment of clinically significant macular edema.
Panretinal photocoagulation (PRP) is used in the treatment of PDR. It involves applying laser burns over the entire retina, sparing the central macular area.

Vitrectomy

 This procedure can be used in PDR in cases of long-standing vitreous hemorrhage (where visualization of the status of the posterior pole is too difficult), tractional retinal detachment, and combined tractional and rhegmatogenous retinal detachment.

Cryotherapy

 When laser photocoagulation in PDR is precluded in the presence of an opaque media, such as in cases of cataracts or vitreous hemorrhage, cryotherapy may be applied instead.

Treatment of diabetic retinopathy varies depending on the extent of the disease. People with diabetic retinopathy may need laser surgery to seal leaking blood vessels or to discourage other blood vessels from leaking. Your optometrist might need to inject medications into the eye to decrease inflammation or stop the formation of new blood vessels. People with advanced cases of diabetic retinopathy might need a surgical procedure to remove and replace the gel-like fluid in the back of the eye, called the vitreous. Surgery may also be needed to repair a retinal detachment. This is a separation of the light-receiving lining in the back of the eye.

If you are diabetic, you can help prevent or slow the development of diabetic retinopathy by:

  • Taking your prescribed medication
  • Sticking to your diet
  • Exercising regularly
  • Controlling high blood pressure
  • Avoiding alcohol and smoking

Risk factors for diabetic retinopathy include:

  • Diabetes. People with type 1 or type 2 diabetes are at risk for developing diabetic retinopathy. The longer a person has diabetes, the more likely he or she is to develop diabetic retinopathy, particularly if the diabetes is poorly controlled.
  • Race. Hispanics and African Americans are at greater risk for developing diabetic retinopathy.
  • Medical conditions. People with other medical conditions, such as high blood pressure and high cholesterol, are at greater risk.
  • Pregnancy. Pregnant women face a higher risk for developing diabetes and diabetic retinopathy. If a woman develops gestational diabetes, she has a higher risk of developing diabetes as she ages.

*The author is no medical expert. But she has diabetic retinopathy and has undergone both laser photocoagulation and panretinal photocoagulation. She regularly sees her retina specialist, Dr. Carlo Nasol at Perfect Sight Center in SM City North Edsa Annex Building, Quezon City.

Vance Madrid

Freelance writer, lifestyle blogger, social media manager, events coordinator, scriptwriter, film buff, wanderlust and certified foodie. Zealous for a keyboard and new experiences, I wish to live and learn through my writing.