From One Medical Student to Another
NPDR is typically managed by optimizing the patient's general health. The best treatment for DR is prevention of its development and progression with tight glucose control (DCCTRG 1993). Patients should maintain a HbA1c ≤7%. Blood pressure management has also been shown to decrease disease progression (UKPDSG 1998) and patients should be counseled to stop smoking. Ophthalmologists should intervene if the patient has clinically significant macular edema (CSME) with NPDR. The causative microaneurysms are localized, often using fluorescein angiography, and then directly treated with laser therapy. If the leakage is more diffuse, a grid of light laser burns can slow the edema. Finally, several off-label medical options are available, such as intravitreous injections of triamcinolone and antibodies against VEGF such as Lucentis or Avastin.
Once a patient has developed PDR, there are several treatment modalities available. Treating macular edema in PDR is similar to treating NPDR. PDR, however, also has additional therapy options aimed at taming the growth of new, problematic vessels. The mainstay of treatment is panretinal photocoagulation (PRP), in which portions of retina are destroyed using thousands of laser burns while sparing the macula. It is hypothesized that this may reduce the amount of ischemic retina, and thus, reduce the production of angiogenic molecules. The treatment may sound extreme, but actually causes surprisingly little vision loss (Frank 1975). It has been found to be extremely effective, reducing the risk of severe vision loss by 50% (ETDRS 1987, Mohamed 2007) and resulting in regression of neovascularization in 30-55% of patients (DRS 1981, "Photocoagulation treatment" 1978).
Patients with non-resolving vitreous hemorrhages or severe traction causing retinal detachment may benefit from a vitrectomy. In this procedure, the vitreous gel and hemorrhage are removed from the eye and replaced with a saline solution.