Background: It is known that the breakdown of the blood-retina-barrier (BRB) as well as the blood-aqueous-barrier (BAB) is one of the earliest pathopysiological changes in the diabetic eye. Some previous studies confirmed a statistically significant increase of flare values of the aqueous humor in eyes with diabetic retinopathy which is lineary correlated with the protein concentration. This study investigated the effect of a central laser photocoagulation in eyes with clinically significant macular edema on the permeability of the blood-aqueous-barrier (BAB).
Patients and methods: We included 22 eyes of 22 patients with diabetes mellitus suffering from clinically significant macular edema determined by fluorescence angiography giving an indication for central laser treatment. Two measurements of aqueous flare were taken, the first before laser photocoagulation (grid with about 100 coagulations) and the second 6 to 8 weeks after treatment.
Results: The flare values before treatment were 11.4 +/- 4.1 phc/ms (4.9-23.8) and after treatment 10.0 +/- 3.5 phc/ms (5.7-16.7). There was a significant difference between both measurements (p = 0.039).
Conclusions: The protein concentration of the aqeoues humor is a parameter which allows to characterize the permeability of the BAB. The central laser photocoagulation seems to seal the vessels.