Comparison of Initial and Deferred Laser Therapy for the Treatment of Type 1 Retinopathy of Prematurity

Abstract

Purpose : To compare the treatment characteristics and outcomes in patients with Type 1 ROP treated with initial and deferred retinal laser photocoagulation

Methods : Retrospective chart review of babies treated for Type 1 ROP at Texas Tech HSC over 15 years. The eyes received either immediate retinal laser photocoagulation (initial laser) or intravitreal bevacizumab injection(s) followed by subsequent laser therapy (deferred laser). Inclusion: Complete documentation of ROP treatment and cycloplegic refraction result(s). Exclusion: Eyes with other risk factors for refractive changes. To account for the potential correlation due to multiple measurements within each subject, the association between the treatments and refractive outcomes were assessed using penalized quasi-likelihood method, a generalized mixed effects model. Eyes were modeled separately and alpha=0.05 was established as threshold for statistical significance.

Results : 98 babies were recruited for the study. Mean gestational age at birth was 26 weeks and mean birthweight was 835g. 160 eyes were treated with initial laser and 33 eyes with deferred laser. The age at diagnosis of Type 1 ROP was significantly different: 34.6 weeks in the initial laser group compared with 33.7 weeks in the deferred laser group (p < 0.001). Babies treated with deferred laser received an average of 1.45 intravitreal injections per eye, with eventual laser therapy at about 43 weeks postmenstrual age. Eyes treated with initial laser required more laser spots and power (p = 0.65) compared with those treated with deferred laser. All eyes achieved eventual ROP regression, without progression to Stage 5 disease and were discharged from ROP screening. At 1st cycloplegic refraction, the refractive error measured in the initial laser group ranged from +6.5D to -12.5D and from +3D to -6.5D in the deferred laser group. (p= 0.03 for right eyes and p=0.11 for left eyes). Subsequent refractive error progression over time was determined and the mixed effect model showed no significant difference between both groups (p = 0.5)

Conclusions : Treatment of Type 1 ROP with deferred laser therapy after intravitreal injection(s) was found to be as safe and effective as initial laser therapy. A wider range of refractive errors, as well as worse myopia, was measured in the initial laser group at entry cycloplegic refraction with no significant difference in subsequent progression.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.