Risk factors for sensation of pain during photocoagulation for diabetic retinopathy - a prospective observational study

Abstract

Background Diabetic retinopathy can be treated by retinal photocoagulation. The treatment may induce discomfort and pain, and due to the individual variation of these adverse effects, it is a challenge to inform patients and to minimise discomfort during treatment. Methods The subjective sensation of pain was evaluated on a numeric rating scale from 0 – 10 in 235 successive patients receiving macular photocoagulation (MP) and 174 patients receiving panretinal photocoagulation (PRP). The influence of first/second eye, treatment session, gender, age, diabetic type, diabetic treatment, duration of diabetes, mean arterial pressure (MAP), body mass index (BMI), glycosylated haemoglobin (HbA1c), visual acuity, right/left eye, number, spot size and effect of applications on the perceived pain was studied. Results The pain score was significantly lower (p<0.001) after the first treatment in the first eye in patients treated with MP 1.67 ±1.8, n=235 (mean ±SD, n) than in patients treated with PRP 2.67 ±2.4, n=174 (mean ±SD, n). Lower mean arterial pressure, higher HbA1c and higher number and effect of the applications contributed significantly to increasing the reported pain during the first treatment in the first eye. For all patients treated in both eyes the reported pain was significantly (p<0.001) higher in the second 2.74 ±2.40, n=269 (mean ±SD, n) than in the first 2.08 ±2.14, n=269 (mean ±SD, n) eye. The pain was significantly higher during the two last than during the first treatment session in patients who received panretinal photocoagulation (p<0.001). Conclusions The higher pain during high treatment intensity and treatment in the retinal periphery might prompt a fractioning of treatment in patients with a low pain threshold. The increased pain with increasing HbA1c and decreasing MAP might be used to individualize information about treatment and to prepare health care professionals about the reactions of the patients.