Evaluation of Visual Outcomes and Retinal Structural Changes Following Multispot Laser Panretinal Photocoagulation in Patients with Proliferative Diabetic Retinopathy

Abstract

Introduction: The development of Proliferative Diabetic Retinopathy(PDR), which is defined as a vision threatening condition resulting in retinal ischaemia with subsequent neovascularisation, is well documented. The treatment using multispot panretinal photocoagulation (PRP), due to its shortened duration and patient comfort, has proven to be a useful treatment modality. However, changes in retinal structural as well as visual function after laser photocoagulation needs further assessment.

Methods: We aimed to determine the visual outcomes and retinal structural changes after multispot laser panretinal photocoagulation (PRP) in PDR. We conducted a longitudinal study of 67 patients with newly diagnosed PDR without any clinically significant macular oedema at Retina Clinic, Government T.D. Medical College, Alappuzha between Jan 2018 and Jun 2019. Best corrected visual acuity(BCVA), Colour vision, visual field analysis, CMT and peripapillary RNFLT measured with Optical Coherence Tomography (OCT) was assessed in the baseline visit, 1, 3, 6 month visits.

Results: Mean CMT showed a progressively significant increase from baseline 236.416.4 µm to 249.423.9 µm at 1 month, 253.125.1 µm at 3 months and 254.625.8 µm at 6 months (p<0.01). Mean RNFLT showed a significant increase in 1 and 3 months followed by a minor insignificant reduction at 6 months. BCVA had significant deterioration throughout the follow up. Colour vision, had a significant reduction, at all follow-up visits compared to baseline. However there was no correlation between BCVA and structural parameters. A mild restriction of visual field was found after laser treatment.

Conclusion: The multispot PRP resulted in significant structural changes and moderate functional changes in retinal status. It remains an effective treatment modality for PDR.