Abstract
Purpose:
To look at the position of new vessels elsewhere (NVE) in R3 patients treated with full pan retinal photocoagulation (PRP). To ascertain whether these NVE arise within an area of retina covered by standard diabetic screening photographs (Two 45° photos centred on the disc and macula).
Methods:
Retrospective data collection from 69 eyes of 47 patients: 25 males and 22 Females whose average age was 64. All patients had undergone full 360° PRP for proliferative diabetic retinopathy. At varying time points after their treatment they had all undergone fundus fluorescein angiography (FFA) for suspected new NVE. FFA was performed with a 50° "Zeiss 450 plus IR" camera. All patients had images centred on the disc and macula as well as 5 peripheral views. The positions of discrete NVE patches were mapped. In particular it was noted whether NVE occurred outside 50° FFA images centred on the disc and macula. If they did it could be concluded that they would also lie outside the 45° screening program images.
Results:
225 patches of NVE and 20 patches of NVD were noted in the 69 eyes analysed. 178 patches of new vessels occurred within 50° FFA images centred on the disc and macula. 70 patches did not occur within these central images. The difference in the distribution of the vessels was significant (p<0.005; unpaired t-test). Out of the 225 patches of NVE, 50 were supero-temporal, 74 infero-temporal, 42 supero-nasal, and 59 infero-nasal. ANOVA showed there to be no significant difference in this distribution (p=0.08). The position of vessels did not vary whether the NVE were within the central 50° images or not (p>0.05 χ2 test). Out of the 69 eyes analysed, 36 had all their new vessels, 27 had some new vessels and 6 had no new vessels within FFA images centred on the disc and macula. Therefore, in the screening program, new vessels would have been missed in 6 eyes giving a 91% sensitivity.
Conclusions:
The majority of eyes analysed had at least some central new vessels that would be likely to be picked up by screening photographs. With hospital eye services under pressure this study helps provide evidence that it would be safe to discharge treated R3 patients to the community. NVE arising in these patients appear to be randomly distributed between quadrants meaning screeners need to analyse all quadrants with equal effort.
Keywords: 499 diabetic retinopathy •
498 diabetes •
688 retina