Abstract
Purpose: :
To compare the change in macular thickness, macular volume, electrophysiology and contrast sensitivity between panretinal photocoagulation with traditional laser system and pattern scanning laser system (PASCAL) in diabetic patients.
Methods: :
Randomized, prospective, interventional and comparative study. We included treatment-naïve patients with clinical diagnosis of severe non-proliferative diabetic retinopathy (NPDR) or proliferative diabetic retinopathy (PDR) and without evidence of macular edema. A panretinal photocoagulation (PRP) was applied in both eyes according to the ETDRS guidelines. The right eye (RE) was treated with conventional laser and the left eye (LE) with PASCAL. At baseline all patients underwent a complete ophthalmological examination and best corrected visual acuity (BCVA) examination. A time-domain optical coherence tomography (OCT), standard electroretinogram and contrast sensitivity assessment (CVS-1000 test) were performed in all case at baseline and day 9, 28, 42 and 85 after treatment. Statistical analysis was performed using SPSS software 17.0 with a repeated measures general lineal model. A p value of less than 0.05 was considered significant (95% level of confidence).
Results: :
We included 100 eyes of 50 patients. The mean age was 63.45 ± 12.04 years. Sixty-two eyes were diagnosed with severe NPDR and 38 with PDR. There was no difference between macular thickness, macular volume, contrast sensitivity, BCVA in both groups. The b-wave in the electroretinogram had a significant difference (p<0.028) through time. B-wave amplitude was smaller in the traditional photocoagulation group. There was no relationship between a smaller b-wave and changes in BCVA, contrast sensitivity or diabetic retinopathy degree.
Conclusions: :
There are no significant differences in BCVA, central macular thickness, macular volume and contrast sensitivity when using the PASCAL system, compared to conventional PRP. The reduction in b-wave amplitude is smaller with the PASCAL system, compared to conventional PRP, which may suggest less damage to retinal tissue.
Keywords: laser • electrophysiology: clinical • diabetic retinopathy