In diabetic maculopathy, fluid rich in fat and cholesterol leaks out of damaged vessels. If the fluid accumulates near the center of the retina (the macula) as indicated by the black pointer there will be distortion of central vision. If too much fluid and cholesterol accumulates in the macula, it can cause permanent loss of central vision. CSME (clinically significant macular oedema) is the term given to describe water logging of the macular area. Most patients with CSME need laser. Your eye care provider can see this when he/she examines your eye.
Diabetic maculopathy requires treatment if fluid is leaking into the macula. The treatment begins with identifying the leaking blood vessels on the fluorescein angiogram. Laser treatment can be applied to seal the leaking vessels. The laser is an intense beam of light which can be finely focused on each individual leak. Laser is effective in stabilizing or improving vision in 75% or patients with macular edema. Despite treatment, 25% of patients continue to lose vision due to recurring leaks. Control of the diabetes and blood pressure is important in reducing the chances of leaking vessels returning following treatment. The fluid often takes up to 2 to 3 months to dry up following closure of abnormal vessels.
Visual recovery is slow and gradual. If the fluid persists, the fluorescein angiogram is repeated to determine the site of the vessels still leaking and laser treatment may be repeated. The average patients needs 2-3 laser sessions per eye to control diabetic maculopathy over the course of their lifetime.
Many eye care providers have wondered why some patients who present with severe maculopathy do well and some do badly. These are some suggestions:
- If a patient presents with severe disease but their diabetes is reasonably well controlled, (HbA1c < 9% and blood pressure reasonable) and it has been for some time, with improvement of their diabetic control they may do very well, keeping central vision and be able to read, though not good enough to drive often.
- If a patient with similar severe retinopathy presents, but their HbA1c >11%, and their BP 200/120, they are likely to do very badly, even if their control is improved (Though without improvement of their control they would be very likely to get a severe CVA/stroke in the near future).
- Most patients will be in between. Smoking appears to me to limit the effect of treatment, and stopping appears to me to be extremely helpful.
- Statins appear to limit lipid deposition in the macula area, and I have been advised by experts to recommend statins to lower the cholesterol, whatever the actual level, in all such patients. This, I believe, appears to limit the exudate plaque formation, and has contributed to better results.
Thus the key may be not to allow the HbA1c to rise at any stage of the diabetes, and to aggressively treat blood pressure. In this way if you do develop retinopathy it should respond better to laser.