Article By

N.V. Nasta

 

Abstract

This article describes the importance of early ophthalmology screening in patients with diabetes and the various treatment options available.

 

 

Introduction:

The ophthalmologic complication of poorly treated diabetes is called Diabetic Retinopathy (DR) which is a leading cause of morbidity in diabetic patients. DR is also a leading cause of visual loss. Retinopathy is the microvascular damage to the retina (Figure 1) that occurs due to hyperglycemia from poorly controlled diabetes. This hyperglycemia makes the basement membrane of the retinal vessels thicker and more permeable so that there is increased permeability causing vascular leaking into the retina and that results in diminished visual acuity or even vision loss.

Figure 1. Comparison between normal retina and diabetic retina showing the retinal findings in DR

Over fifty percent of patients with known diabetes have some degree of diabetic retinopathy. The duration of diabetes is also related to the chance of developing diabetic retinopathy. Most patients who develop diabetic retinopathy are asymptomatic in the early stages and thereafter, the progression can be rapid, leading to vision loss. Hence, the need for regular ophthalmology screening in diabetics for early detection and treatment of diabetic retinopathy. These include annual eye examinations, as well as keeping blood sugar, blood pressure and blood cholesterol under the best possible control.

Diabetic eye problems require treatment if there is blurry or double vision, dark or black spots, pain or pressure in eyes and trouble seeing from the corner of the eyes. Visual loss from diabetic retinopathy is commonly due to macular edema, retinal detachment, retinal haemorrhages and neovascular glaucoma.

 

DIAGNOSIS:

Comprehensive ophthalmology exams after dilatation, along with fluorescein angiography help to visualize the retina so that neovascularization and leaking from capillaries can be assessed (Figure 2).

Figure2-Retina

Figure 2 : Retina with neovascularization, hemorrhages and exudates

In addition, an optical coherence tomography (OCT) scans the retina and gives exact retinal thickening and helps to decide the appropriate management.

 
TREATMENT

If you have mild retinopathy, you may need close follow-up and may not require treatment right away. Severe diabetic retinopathy requires prompt surgical treatment.

  1. MEDICATION : Anti – vascular endothelial growth factor (VEGF) given as intravitreal injections.[1,2] These VEGF inhibitors mechanism of action is by shrinking the new and leaky blood vessels in proliferative diabetic retinopathy and is also often used in conjunction with laser. These may be repeated every month.
  2. LASER PHOTOCOAGULATION : This works by stopping the leakage of blood and fluid in the retina and thus, slows down the progression of diabetic retinopathy and vision loss. In photocoagulation, a highenergy laser beam creates small coagulation areas in the retina with abnormal blood vessel proliferation and helps seal any leaks.[3] The procedure takes place in the ophthalmology office. Fluorescein angiography photographs may serve as maps to show where the laser burns should be placed. During the procedure, the patient may see bright flashes from the short bursts of high-energy light. Shortly after laser treatment, patients can usually return home however they may have blurry vision for about a day. Even when laser surgery is successful in sealing the leaks, new areas may appear later. For this reason, it is necessary to monitor patients with follow- up visits and additional laser treatments if necessary.
  3. VITRECTOMY : A vitreous hemorrhage may clear up on its own. However, if the hemorrhage is massive and doesn’t resolve, a vitrectomy (surgical removal of vitreous) may help to restore vision and can be followed by application of laser treatment. A vitrectomy is also used to remove scar tissue of retinal detachment.[4] This allows a detached retina to settle back and flatten out. Full recovery may take weeks.

 

IMPORTANT POINTS:
  • Diabetic retinopathy is one of the leading causes of visual loss.
  • Regular ophthalmology screening is a must in all diabetics for early detection and prevention of diminished visual acuity or loss.
  • Proper management of diabetes with glycosylated haemoglobin (HbA1C) under 7mg/dl to prevent the onset of eye complications
  • Once retinopathy has set in, prompt treatment with medications and laser photocoagulation can prevent further progression of vision loss, if initiated early on.

 

Nikhil V. Nasta, MS (Ophth), DNB, ICO (Lon) Director I-Sight Eyecare & Surgery 402, Sapphire Building, S.V.Road, Khar (W), Mumbai 400052. Telephone: 022 – 26485231 / 26485232 Email: info@isighteyecare.com

References:

1. Avery RL, Pearlman J, Pieramici DJ, et al.Intravitreal bevacizumab (Avastin) in the treatment of proliferative diabetic retinopathy. Opthalmology. Oct 2006;113(10): 1695-1705.
2. Spaide R F, Fisher  Y L. Intravitreal bevacizumab (Avastin) treatment of proliferative diabetic retinopathy complicated by vitreous hemorrhage. Retina. 2006
3. Lee CM, Olk RJ. Modified grid laser photocoagulation for diffuse diabetic macular edema: Long-term visual results. Ophthalmology. Oct 1991; 98(10): 1594-1602.
4. Flynn HW Jr, Chew EY. Pars Plana vitrectomy in the early treatment diabetic retinopathy study : ETDRS Report Number 17. Ophthalmology Sep 1992; 99(9):1351-1357.