Abstract
Purpose:
To asses if PPP, a new laser treatment technique to treat patients with PDR with indication of PRP (with or without indication of vitrectomy), reduces progression and avoids ablative scars in equatorial retina.
Methods:
Twenty four eyes from 18 diabetic patients (25-72 y.o.) with proliferative retinopathy with indication of PRP and naif of laser treatment, were trated with PPP. Eyes with less than 100 shots were considered naif.<br /> PPP is a modification of PRP, an intense laser treatment aiming burns to an area restricted between ora serrata and a line situated on the anterior edge of vortex veins. Laser treatment were delivered during a pars plana vitrectomy PPV (14 cases) when it was indicated or by indirect ophthalmoscopy (10) when it was not. In every case treatment required more than 1000 and less than 2000 shots of a 23G endoprobe or indirect ophthalmoscope beam from a Ophthalas 532 Eyelit Alcon. Treated eyes where classified acording to a severity scale to asses if they progresed 2 or more levels on severity. This was the primary endpoint. They were followed for 50 to 6 mos. Vitreous hemorrages, diabetic macular edema, retinal detachment, and rubeosis were assesed as secondary endpoints as signs of progression.
Results:
None of the 24 eyes progresed on the severity scale at follow up. Two patients had had vitreous hemorrage that requiered PPV (one treated through IO laser and one by endolaser). There were no cases of retinal detachment, nor rubeosis.
Conclusions:
All trated eyes did not progress on severity scale with PPP. Most of them regressed on scale to a lower level. This is sugestive of effectiveness of this modification of the classic laser treatment. Antiangiogenic therapy for diabetic macular edema showed in clinical trials revascularization of capillary drop out areas at the equator, so a conservative approach seems to be more logic than PRP. Panoramic angiography demonstrate that extreme periferia is the first and the most isquemic area in diabetes, and so more angiogenic. Most of patients treated with PRP do not show scars at the extreme perifery, and instead have intense scars at equator.Some progress on severity anyway. Partial Periferic Photocoagulation (PPP) preserves retina between temporal arcades and vortex veins line. The weakness of this serie is that in cases of PPV laser, surgery could bias the results. But PPV and no PPV eyes showed no difference.