DIABETIC RETINOPATHY

• Damage to retina caused by complications of Diabetes mellitus.
• Risk of diabetic retinopathy higher in Type I DM.

Risk factors for development of diabeteic retinopathy in diabetic patients:

1. Duration of disease: most important risk factor

2. Sex: more in females

3. Poor glycemic control

4. Accompanying factors:

• Hypertension
• Smoking
• Poor renal status
• Hyperlipidemia

5. Pregnancy: may accelerate the changes of diabetic retinopathy

OCULAR MANIFESTATIONS

A) Non-proliferative diabetic retinopathy (NPDR):

• Earliest stage of diabetic retinopathy is NPDR.
• Includes Background retinopathy (early NPDR) & pre-proliferative retinopathy (advanced NPDR).
• Ocular manifestations are:

i) Microaneurysms :

• Early ophthalmoscopically detectable change
• Involves inner nuclear layer

ii) Retinal hemorrhage: both deep (dot-blot) & superficial (flame-shaped)

iii) Hard exudates & in advanced NPDR soft exudates (cotton-wool spots)

iv) Retinal edema (Retinal thickening) at macular area (macular edema).

v) Venous abnormalities

B) Proliferative diabetic (PDR):

• Hallmark of PDR is the occurrence of neovascularisation.
• When arises on or within one disc diameter of the optic nerve head (optic disc), it is referred to as neovascularisation of the disc (NVD).
• When it arises farther than one disc diameter away, it is called neovasculrisation elsewhere (NVE) in the fundus.
• Complications of PDR:

1. Vitreous hemorrhage
2. Fibrovascular proliferation
3. Tractional retinal detachmet

C) Diabetic maculopathy:

• Associated with NPDR or PDR.
• Diabetic macular edema occurs due to increased permeability of retinal capillaries.
• Macula edema termed as clinically significant macular edema (CSME), if one of the following three criteria are present:

1. Thickening of retina at or within 500 micron of the centre of the fovea.
2. Hard exudate at or within 500 micron of the centre of fovea.
3. Development of a zone of retinal thickening one disc diameter or larger in size.

D) Advanced diabetic eye disease:

• End stage of uncontrolled PDR.
• Marked by complication such as:

1. Persistent vitreous hemorrhage
2. Tractional retinal detachment
3. Neovascular glaucoma (rubeosis iridis)

Other ocular manifestations of DM:

• Cataract
• Myopia
• Rarely hypermetropia
• Cranial nerve palsy: 3^rd (most common), 4^th,6^th,7^th

VISION LOSS IN DIABETIC PATIENT

• Retinopathy & cataract are complications of diabetes that may lead to visual impairment & blindness.

1. Cataract:

• M/c cause of severe visual loss in people with type 2 DM.
• Cataract causes gradual progressive loss of vision.

• M/c cause of vision loss in patient with NPDR.
• Though macular edema may cause sudden painless loss of vision

• M/c cause of vision loss in PDR
• M/c cause of sudden painless loss of vision.
• Patient gives h/o sudden onset of floaters followed immediately by severe vision loss.

• 2nd m/c cause of sudden painless loss of vision in PDR.
• If central retina is not involved, vision loss may be gradual.

• Protein kinase ‘C’ inhibitors
• VEGF inhibitors
• antioxidants
• Vitamin E

• Remains the mainstay of treatment of diabetic retinopathy & diabetic maculopathy
• Focal laser photocoagulation & Grid pattern photocoagulation
• Panretinal photocoagulation for proliferative retinopathy.

• Indicated in advanced PDR.
• Pars plana vitrectomy is the treatmentof choice