A 56-year-old insulin requiring Type II Diabetic patient presented with rapid onset deteriorating vision of his right eye. He has been diabetic for last 12 years and was on insulin for last 2 years. His sugar and BP was not very well controlled.
Recent blood tests showed his HbA,C was >8.5% and both LDL and triglyceride level were elevated. His BP was 170/100 m/Hg. Opthalmoscopic examination of the left eye showed presence of proliferative retinopathy with haemorrhage and exudates while the right retina could not bevisualised properly. He was urgently referred to the opthalmologist who diagnosed it to be a case of vitreous haemorrhage in the right eye.
Diagnosis:  Diabetic retinopathy with vitreous haemorrhage of the right eye.
Discussion
Visual problem is a common complaint faced by the primary care physicians. Although the patients are finally referred to the opthalmologists, the initial assessment and management are done by the physicians and a working knowledge of the condition is very much essential in order to give appropriate consultation to the patients.
While examining such a patient, a physician needs to evaluate quickly certain points e.g,
Visual acquity by finger counting method
Visual field by confrontation method - papillitis
Ocular movement - cranial nerve palsy
Pupil reaction and size - ego trauma, drugs
Anterior chamber - conjunctiva, cornea, iris - infection etc.
Posterior chamber - retina by an opthalmoscope diabetic retinopathy.
Before proceeding any further, non-pathological causes of deteriorating vision like refractive error should be considered and tested.
Common causes of diminished vision
A. Acute unilateral painless -
Vitreous haemorrhage - history of diabetes
Retinal detachment
Retinal vein-occlusion
Retinal artery occlusion
Retinal artery embolism - Amaurosis fugax
B. Acute unilateral painful -Y Trauma
Infection - ego cornea! ulcer due to herpetic infection
Papillitis - eg in multiple sclerosis
Glaucoma - headache, vomiting
Cranial arteritis - headache, high ESR
C. Acute bilateral painless -
In patient with poorly controlled diabet
    Some anticholinergic agents may caw
D. Acute bilateral painful -
Rarely infection, trauma, glaucoma
E. Gradual unilateral painless
e.g, cataract, senile macular degenera
F.  Gradual, unilateral painful
Neoplastic lesion like retro orbital tumours
Inflammatory lesion like granulomas
CT or MRI scan may be helpful.
G. Gradual bilateral painless -
e.g, cataract, macular degeneration
Drugs - hydroxychloroquine, ethambutol
H. Gradual bilateral painful
Inflammatory conditions like sarcoidos, collagen vascular disorders.
This patient was clinically diagnosed to have proliferative retinopathy with probable vitreous haemorrhage. He was urgently referred to opthalmologist for treatment.
Discussion
Diabetic retinopathy is one of the leading causes of vision loss in adults. Patients with Type I diabetes are at a higher risk of developing more severe retinopathy. Patients with Type II diabetis has a lower prevalence of retinopathy and tend to have less severe disease. However, Type II diabetes comprises 90% of the population with diabetes and thus comprises a larger proportion of those affected with diabetic retinopathy.
Risk Factors
Modifiable risk factors:
1. Hypertension
The results of DCCT and UKPDS show that although intensive therapy of blood glucose control does not prevent retinopathy completely, it does reduce the risk of development and progression of diabetic retinopathy. This may be translated clinically to both preservation of vision and reduction in therapies e.g, laser photocoagulation.
2. Hypertension
In UKPDS study, tight BP control, was associated with a 37% reduction of microvascular diseases, predominantly reduced risk of retinal photocoagulation Beta blockers and ACE inhibitors were equally effective.
3. Serum lipid levels
Raised triglyceride and LDL levels were associated with increased incidence of proliferative diabetic retinopathy.
4. Other risk factors
Diabetic neuropathy - the risk of diabetic retinopathy is 5 times more common in patients with neuropathy. Presence of anaemia and hypoalbuminaemia also increase the risk of retinopathy.
Management
Although management is done by an opthalmologist, primary prevention remains the most effective way to treat diabetic retinopathy and involves limiting modifiable risk associated with glucose control, BP and lipid control.
Both DCCT and UKPDS demonstrated that the importance of maintaining good metabolic control to prevent worsening or development of retinopathy.
UKPDS clearly showed that controlled BP substantially reduces the risk of progression of diabetic retinopathy and visual loss in diabetic patients.
Tight BP control (Mean 144/82) resulted in 35% reduction of retinal photocoagulation and a 34% reduction in progression of diabetic retinopathy.
Diabetic nephropathy is a strong predictor of diabetic eye disease. Patients with early nephropathy should be aggressively treated with diet and ACE inhibitors in order to reduce the incidence of retinopathy.
Although increased lipids is associated with worsening of retinopathy, there is no conclusive evidence that lowering the level improves retinopathy. However, from cardiovascular point of view, aggressive lipid lowering strategy should be taken.
Physical exercise which can cause sudden rise in systolic B.P. should be discouraged as this may worsen vitreous haemmorhage.
Low risk exercise like cycling, swimming and walking should be encouraged. Close watch should be done during pregnancy, as it might worsen retinopathy. From this discussion it is evident that primary care physician has a big role to play in the primary prevention of diabetic retinopathy.
This patient had vitreous haemorrhage and after proper evaluation by the opthalmologist, underwent vitrectomy and laser photocoagulation. Unfortunately the recovery of the vision of his right eye was suboptimal.
Key Points
Deteriorating vision is a common clinical presentation in primary care practice. Primary care physician should attempt to make a clinical diagnosis before referring to an opthalmologist.
Diabetic retinopathy is a common condition for deteriorating vision.
At primary care level meticulous management of blood glucose, BP and lipid levels are the best way of preventing diabetic eye disease.
Source:  “Experience with Evidence in Clinical Practice,” Dr. Subrata Maitra,  Soma Book Agency.