Panretinal photocoagulation versus intravitreal injection retreatment pain in high-risk proliferative diabetic retinopathy

Dor em panfotocogulação retiniana versus injeção intravítrea em pacientes com retinopatia diabética proliferativa de alto risco

PURPOSE: To compare pain related to intravitreal injection and panretinal photocoagulation in the management of patients with high-risk proliferative diabetic retinopathy. METHODS: Prospective study including patients with high-risk proliferative diabetic retinopathy and no prior laser treatment randomly assigned to receive panretinal photocoagulation (PRP group) or panretinal photocoagulation plus intravitreal ranibizumab (PRPplus group). In all patients, panretinal photocoagulation was administered in two sessions (weeks 0 and 2), and intravitreal ranibizumab was administered at the end of the first laser session in the PRPplus group. Retreatment was performed at weeks 16 and 32 if active new vessels were detected at fluorescein angiography. Patients in the PRPplus group received intravitreal ranibizumab and patients in the PRP group received 500-µm additional spots per quadrant of active new vessels. After the end of retreatment, a 100-degree Visual Analog Scale was used for pain score estimation. The patient was asked about the intensity of pain during the whole procedure (retinal photocoagulation session or intravitreal ranibizumab injection). Statistics for pain score comparison were performed using a non-parametric test (Wilcoxon rank sums). RESULTS: Seventeen patients from PRPplus and 14 from PRP group were evaluated for pain scores. There were no significant differences between both groups regarding gender, glycosylated hemoglobin and disease duration. Mean intravitreal injection pain (±SEM) was 4.7 ± 2.1 and was significantly lower (p<0.0001) than mean panretinal photocoagulation pain (60.8 ± 7.8). Twelve out of 17 patients from the PRPplus group referred intensity pain score of zero, while the minimal score found in PRP group was found in one patient with 10.5. CONCLUSION: In patients with high-risk proliferative diabetic retinopathy who needed retreatment for persistent new vessels, there was more comfort for the patient when retreatment was performed with an intravitreal injection in comparison with retinal photocoagulation. Further larger studies are necessary to confirm our preliminary findings.

Pain; Intravitreal injections; Diabetic retinopathy; Light coagulation; Vascular endothelial growth factor A

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