Diabetes, Hypertension, Obesity , Dyslipidemia form a spectrum of Metabolic Syndrome and these diseases have become quite common place now with changes in lifestyle, sedentary work, fast food, lack of excercise and sports. Out of these, Diabetes is one of the most damaging to the body as it affects the eye (retinopathy), nerves (neuropathy-peripheral and autonomic), kidney (nephropathy), fungal infections, diabetic ulcers, low immunity and chronic morbidity. With associated diseases like hypertension and dyslipidemia, the chances of mortality due to coronary artery disease and cerebrovascular accidents also increase.
DIABETIC RETINOPATHY is one of the leading causes of blindness in current demographic scenario and because of its indolent nature of development, can go unnoticed by patient for long. Besides retinopathy patients can also suffer from dry eyes, epithelial erosions, faster cataract progression, herpetic infections, frequent styes and chalazions, diabetic papillopathy.
What is Diabetic Retinopathy:
Due to constant high level of blood sugar, there is chemical changes in the cellular lining of the retinal microvasculature. This causes the cells to die out or lose their functionality. Because of loss of these supporting cells, initially there is leakage from vessels. With further damage, the blood vessels start getting blocked and the part of retina which they supplied, die because of lack of oxygen and nutrition. Dying cells lead to production of AntiVEGF, a chemical which induces formation of new vessels. This new vessels are not properly developed and cause leakage, bleeding and also along with the vitreous, start pulling on the retina. This pull on the retina can cause Tractional Retinal Detachment with severe visual loss if the fovea is involved.
Stages of Diabetic Retinopathy:
To start with, there is
NON PROLIFERATIVE DIABETIC RETINOPATHY (NPDR), subclassified as
- Mild NPDR- few microaneurysms
- Moderate NPDR- dot blot haemorrhages, Cotton Wool spots, hard exudates
- Severe NPDR- all four quadrants of the retina have haemorrhages, with intraretinal microvascular abnormalities(IRMAs), venous beading.
PROLIFERATIVE DIABETIC RETINOPATHY characterised by
- New vessels at disc, or
- New vessels elsewhere
- Tractional retinal detachment threatening or involving macula.
Both NPDR and PDR may also have a component of CSME (clinically significant macular edema) wherein there is swelling at the part of the retina where accurate vision is formed (the fovea), leading to significant visual loss. Some patients also present with sudden vision loss, due to vitreous haemorrhage from new vessels.
Symptoms of Diabetic Retinopathy:
Most early stages are without symptoms.
- Blurring of vision
- Sudden diminution of vision in cases of vitreous haemorrhage, retinal detachment
- Frequent changes in glass prescription because of advancing cataract
The best management of diabetic retinopathy is to prevent it from developing in the first place. It can be achieved by keeping one’s Blood sugar under tight control (HbA1c <6.5), tight blood pressure control and control of dyslipidaemia. 6monthly – annual check-ups with the ophthalmologist to get the fundus evaluated, so that retinopathy can be caught at the first instance and managed appropriately.
- A simple slit lamp biomicroscopic dilated fundus evaluation with a 90D or using Indirect Ophthalmoscope can diagnose Diabetic Retinopathy.
- Colour Photograph and red free filter, for baseline and follow ups.
- OCT macula, to quantify macular oedema and follow up on response to treatment.
- FFA (Fundus Fluorescein Angiogram) to look for microaneurysm, capillary non perfusion areas, neovascularisation and macular perfusion/ischemia.
- Ultrasonogram may be done in cases with dense vitreous haemorrhage to look for the status of retina vis. Retinal Detachment.
Multimodal treatment options are available.
- First and foremost, as mentioned earlier, is a tight control of Blood Pressure and Blood sugar.
- Mild NPDR cases can be followed up in the OPD.
- Patients with mild retinal thickening at fovea without any leak on FFA can be given a trial of Nepafenac eye drops three times a day as conservative management.
- Patients with CSME, neovascularisation require intravitreal injections of AntiVEGFs like bevacizumab, ranibizumab or aflibercept monthly for three months as loading dose. Triamcinolone acetonide injection is often added with AntiVEGFs to counter inflammatory component. Inj. Orzudex (dexamethasone implant) has also been used in recalcitrant DME cases, as a single injection works within the vitreous cavity for around 3 months, removing the need for monthly injections.
- Pan Retinal Photocoagulation/ Focal Laser- if FFA shows capillary non perfusion areas, neovascularisation etc- then retina has to be lasered so as to remove the main culprit causing AntiVEGF load to rise within the vitreous cavity. Usually laser is done as a compliment to AntiVEGF injections. Around 2 weeks post injection, lasers are done. PRP may be completed in 2-3 sittings.
- Surgical management: patients with dense vitreous haemorrhage, non resolving vitreous haemorrhage, tractional retinal detachment; need surgical management. This includes MIVS (minimally invasive vitrectomy surgery) with Silicon oil/ gas injection with Endolaser assisted PRP.
Retinopathy cases detected early and patients adhering to treatment and follow up protocols, gain and maintain very good vision for long. Hence, it is important to consult an ophthalmologist in case you have diabetes since long or have been recently diagnosed with the same.