Bevacizumab as Adjunctive Treatment to Laser Panretinal Photocoagulation for Proliferative Diabetic Retinopathy

Structural and Functional Evaluation of the Macula in Patients With Proliferative Diabetic Retinopathy Treated With Panretinal Photocoagulation and Bevacizumab (Avastin ®)

This is a prospective, randomized and comparative study is to quantify the functional and structural alterations of the macula in patients with proliferative Diabetic Retinopathy submitted to laser photocoagulation and to evaluate the efficacy of intravitreal bevacizumab as a adjuvant therapy in preventing the adverse events of that procedure. The patients with proliferative Diabetic Retinopathy (DR) with indication of binocular laser photocoagulation will be examined by ophthalmologists who will measure the visual acuity and contrast sensitivity, perform slit lamp examination, fundus examination and optic coherence tomography before and after laser photocoagulation. Laser photocoagulation will be performed in both eyes according Early Treatment Diabetic Retinopathy Study that advocate the realization of 3 episodes of laser photocoagulation in 3 weeks. This comparative study analyses the effect of intravitreal bevacizumab one week before laser photocoagulation and one, three and six months after the randomization visit. The fellow eye will be submitted only to laser photocoagulation and will be considered as control. It is estimated a sample of 30 patients. All procedures, purposes and methods will be explained to all patients.

The current gold standard for the treatment of proliferative diabetic retinopathy is panretinal photocoagulation. Therefore this study is designed using both treatments in the same patient: intravitreal Bevacizumab plus panretinal photocoagulation in one eye, compared to panretinal photocoagulation alone in the contralateral eye. These patients had their visual acuity and contrast vision measured and complete ophthalmological examination was performed, including macular slit lamp examination, fluorescein angiography and optical coherence tomography.

Patients with similar proliferative diabetic retinopathy without high risk characteristics receive laser therapy in both eyes and intravitreal Bevacizumab injections in one eye. For the Bevacizumab injections, numbing drops, antibiotic drops, and drops to dilate the pupil, and possibly and anesthetic injection, are put in the eye before the medicine is injected into the vitreous. Patients return for follow-up visits 1 day, 1 and 4 weeks after the injection, and then 3 and 6 months. Patients whose condition does not improve may undergo new evaluation.

Inclusion Criteria:

• Proliferative diabetic retinopathy eyes.
• Best Corrected-Visual Acuity at baseline > 20/320 in the study eye.
• Patients with and without diabetic macular edema
• Type II diabetic subjects as defined by the World Health Organization
• aged ≥ 18 years.
• Women must be using effective contraception
• Ability to provide written informed consent.
• Indication of panretinal photocoagulation in both eyes

Exclusion Criteria:

• Vitreous hemorrhage or pre-retinal hemorrhage
• Eyes with prior scatter (panretinal) or focal/grid photocoagulation, within the previous 6 months.
• Atrophy/scarring/fibrosis/ hard exudates involving the center of the macula.
• Cataract
• Any intraocular surgery within 6 months before trial enrollment.
• Previous vitrectomy.

Any of the following underlying systemic diseases:

History or evidence of severe cardiac disease or previous thrombus-embolic event