Patient Comfort with Yellow (577 nm) vs. Green (532 nm) Laser Panretinal Photocoagulation for Proliferative Diabetic Retinopathy

Abstract

Pain associated with panretinal photocoagulation (PRP) can adversely affect the number and quality of retinal burns delivered and subsequently increase the number of treatment sessions required to achieve regression of proliferative diabetic retinopathy (PDR). We assessed comfort in patients undergoing treatment with yellow (577 nm) vs. green (532 nm) PRP for PDR. Prospective, single-center, randomized crossover clinical trial. Patients with PDR with high-risk characteristics. Subjects were equally randomized to first receive PRP with a laser indirect ophthalmoscope with either green (IQ 532; IRIDEX, Mountain View, CA) or yellow (IQ 577; IRIDEX) laser, followed by additional treatment with the opposite laser using standardized settings in the superior hemisphere of a single treatment eye per patient. Topical anesthetic was used in all study eyes before each treatment and power was titrated until moderate grey-white retinal burns were achieved. The primary outcome measure was patient's perceived pain as measured with a standardized 10-point pain scale. Secondary outcome measures included laser power, treatment time, number of treatment shots with each laser, and physician ease-of-use score with each laser on a 10-point scale. Forty patients (40 eyes) with a mean age of 54.0 years were enrolled. Mean pain scores were similar when comparing treatment with yellow and green laser (3.1 ± 2.3 vs. 2.8 ± 2.6; P= 0.40). No significant difference was seen in visual acuity (P= 0.44) or central macular thickness (P= 0.39) 1 month after PRP. Additionally, there were no significant differences when comparing minimum power required (243.2 ± 74.2 vs. 234.0 ± 59.6 mW; P= 0.55), treatment time (5.1 ± 3.6 vs. 5.6 ± 3.9 minutes; P= 0.384), and number of treatment shots (257.6 ± 12.6 vs. 258.0 ± 2.3; P= 0.68). Six of 7 co-investigators (85%) preferred using yellow laser over green and reported ease-of-use scores of 9.0 ± 1.2 and 7.6 ± 1.4, respectively (P= 0.07). No severe adverse events occurred. Patient comfort during PRP for PDR utilizing laser indirect ophthalmoscopy is similar for green and yellow wavelengths.