Objective To observe the efficacy and safety of laser photocoagulation on highrisk prethreshold versus threshold retinopathy of prematurity (ROP). Methods Ninety-seven ROP infants (186 eyes)， which included 88 high-risk prethreshold ROP eyes and 98 threshold ROP eyes, were enrolled in this study. Among the 186 eyes, 70 eyes were zone one and 116 eyes were zone two. Laser photocoagulation with 810 nm wavelength using binocular indirect ophthalmoscopy was used in all the infants under general anesthesia. Follow-up ranged from 35 to 852 days with a mean of (316±274) days. The degree of retinopathy alleviation and progress were observed. ResultsAmong the 186 eyes, complete abatement of retinopathy was found in 168 eyes (90.3%), local retinal detachment was found in eight eyes (4.3%). The complete abatement of retinopathy was found in 84 eyes both in high-risk prethreshold group (95.5%) and threshold group (85.7%), while progressive retinopathy was found in four eyes in the high-risk prethreshold group (4.5%) and 14 eyes in threshold group (14.3%). The difference in recovery rate was statistically significant between two groups (χ2=3.98,P＜0.05). The abatement of retinopathy was found in 56 eyes in zone one group (80.0%) and in 112 eyes in zone two group (96.6%), while progression of retinopathy was found in 14 eyes in zone one group (20.0%), and 14 eyes in zone two group (3.4%). The number of eyes with progressive retinopathy in zone one group was obviously higher than that in zone two group. The difference was statistically significant (χ2=11.86，P＜0.01). No treatmentrelated complications were observed during the follow-up period. ConclusionsLaser photocoagulation is effective in treating high-risk prethreshold and threshold ROP. Early intervention could improve prognosis. There was no treatment-related complication during the follow-up duration.
To introduce the definition, applicable scenarios, methodology and examples of mixed methods systematic reviews, aiming to promote the application of mixed methods in China and to help clinical decision-makers to select appropriate qualitative results from systematic reviews to guide clinical practice.