Complications of Diabetic Retinopathy
1- Unstable vision
High blood sugar can cause swelling of the natural intraocular lens which leads to change in vision. Glucose enters inside the lens and pull fluid with it. This swelling changes the refractive power of the lens causing blurred vision
Intraocular natural lens Opacification develops due to uncontrolled blood sugar. This opacification is called Cataract. The most common type of cataract occurs in diabetic patient is posterior subcapsular cataract. The density of this opacification increases gradually in faster way comparing to healthy people.
Due to ischemic changes of the eye there are continuous release of inflammatory enzymes and growth factors from the retina.
These enzymes and factors can cause the growth of new abnormal blood vessels on the iris and also in the angle. The drainage of aqueous humor occurs through trabecular meshwork that is located at the angle of the eye.
These new blood vessels are called iris neovascularization. These neovascularization can block the angle completely and prevent the drainage of aqueous humor outside the eye which leads to high intraocular pressure. Also these new blood vessels can form scar that grows gradually towards the angle and also invade the trabecular meshwork.
Iris neovascularization can bleed easily and blood can accumulate in the anterior part of the eye which also can cause high blood pressure. This type of glaucoma is called neovascular glaucoma which is type of angle closure glaucoma.
4- Vitreous haemorrhage
Ischemia of the retina can cause release of enzymes, inflammatory cells and growth factors that cause the growth of new blood vessels in the retina. These new blood vessels are weak and bleed easy inside the retina and also into the surrounding vitreous. Vitreous haemorrhage can cause sudden loss of vision. Usually the eye absorbs this haemorrhage gradually over few weeks but sometime it can persist and the only way to treat it is by surgery and vitrectomy
5- Fibrovascular membrane and retinal detachment
Retinal new blood vessels can form and stimulate the growth of fibrous membranes and scar tissues that are attached firmly to the retina and retinal blood vessels. Traction of these fibrous membranes can pull the retina away from the underlying choroid and causes retinal detachment
6- Macular edema and exudate
Fluid and lipid and other factors are leaked continuously from damaged retinal blood vessels. If the leaker in or near the macula, vision will be badly affected.
Untreated diabetic retinopathy can lead to one or all of the above complications which can cause gradual irreversible loss of vision.