Abstract
Purpose: :
To investigate the clinical effects and safety profile of targeted Pascal® retinal laser photocoagulation (TRP) in treatment-naive proliferative diabetic retinopathy (PDR) and diabetic macular edema (DME).
Methods: :
Prospective, phase 1 clinical trial. We used ultra-wide 200º angle fluorescein angiography (Optos®, optomap®) to visualise zones of retinal capillary non-perfusion and intermediate retinal ischaemia. The TRP strategy used 20ms multi-spot Pascal® 4*4/5*5 arrays, and 1,500 burns TRP were applied in a single-session (SS) only to areas of peripheral retinal ischaemia as per Optos® imaging. ETDRS visual acuity (VA), central retinal thickness (CRT, µm, 3D-OCT), 24-2 SITA-Std and Estermann VFs recorded at baseline, 1, 3 and 6 months post-laser. Laser powers, pain responses, and treatment times were recorded. Paired t-test analysis was performed.
Results: :
Results reported for 26 eyes (18-PDR, 8-DME). Average power required was 236mW (SD 65), with TRP delivered in a time of 3.9 minutes (SD 1.4). Numerical pain score post-TRP was 2/10 (n=26; SD 2.5; graded mild). VA increased significantly by +4 letters at 1-month (n=26) and 3-month (n=16) visits (p<0.05). There were no significant changes in CRT over time (-2.3µm at 1-month, -13.2µm at 6-months; p=0.42). The Mean Deviation on SITA-VFs increased significantly after 1-month (n=26; +1.19dB, p<0.001), with no significant worsening of VFs at other time-points. No patients failed Estermann driving VF standards post-TRP. There were no laser re-treatments required at 1-month post-TRP (n=26). In the PDR group, 50% eyes (5/10) required further top-up TRP and 50% (5/10) showed regression at 3-months. There were no laser-related ocular complications.
Conclusions: :
This pilot study reports that Optos® widefield angiography-guided SS-Pascal® 20ms TRP using 1,500 burns has a favourable safety profile, and TRP shows promise as a comfortable and less invasive procedure in PDR.
Clinical Trial: :
Central Manchester Univ Hosp, R & D Trial Reg#R00520
Keywords: diabetic retinopathy • laser • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)