Abstract
Purpose: :
To explore the spatial distribution of functional loss and the effect of Optos® -guided PASCAL® laser therapy on central visual field (VF) in untreated proliferative diabetic retinopathy (PDR).
Methods: :
VF data (SITA 24-2) from 99 eyes (66 patients) with treatment-naive PDR were used to train a self-organizing map (SOM) and classified the defects into 9 patterns. 28 eyes of 23 patients treated with 20-millisecond PASCAL®retinal laser photocoagulation underwent OPTOS® widefield fundus fluorescein angiography (WF-FFA) at baseline and 3-months post treatment. Pre- and post-treatment changes of VF (SOM patterns, Mean Deviation (MD) and Pattern Standard Deviation (PSD)) were compared. Improvements of VF defect (Total Deviation, TD) at different eccentricities (0-10, 10-20 20-30 degrees) were also investigated and correlated with the extent of initial loss. Grading of WF-FFA post-laser was undertaken by 2 masked retina specialists.
Results: :
At baseline 44.4% of PDR eyes showed early VF loss patterns (1 to 3) with 23.2% classified into the advanced patterns (7 to 9). Mild SOM patterns had more superior hemifield VF defects while advanced patterns involved both superior and inferior hemifield VF loss. Following laser a significant shift to early SOM patterns were observed (p=0.02), as well as improvement of MD and PSD (p=0.003 and 0.06 respectively). Improvement of TD was observed commonly in test locations of 0-10, 10-20 and 20-30 degrees (39.3%, 60.7%, 64.3% separately) and the differences between three zones was not significant (p=0.35). Greater improvement was observed with deeper baseline TD (p<0.001). Masked, WF-FFA image grading showed 78.6% PDR regression.
Conclusions: :
The SOM method is a promising technique to classify and monitor over time PDR-associated VF defects. Optos® -guided PASCAL® 20-millisecond retinal laser treatment improved the spatial patterns and global parameters of central VF defects.
Keywords: diabetic retinopathy • visual fields • laser