Electroretinographic Responses in Retinopathy of Prematurity Treated Using Intravitreal Bevacizumab or Laser.

PURPOSE: Intravitreal injection of bevacizumab (IVB) offers advantages over laser photoablation for treatment of type 1 retinopathy of prematurity (ROP). However, retinal function has not, to date, been quantitatively compared following these interventions. Therefore, electroretinography (ERG) was used compare retinal function among eyes treated using IVB or laser, and control eyes. In addition, among the IVB-treated eyes, ERG was used to compare function in individuals in whom subsequent laser was and was not required. DESIGN: Prospective clinical cohort study. METHODS: ERG was used to record dark- and light-adapted stimulus/response functions in 21 children treated using IVB (12 of whom required subsequent laser in at least 1 eye for persistent avascular retina [PAR]). Sensitivity and amplitude parameters were derived from the a-wave, b-wave, and oscillatory potentials (OPs), representing activity in photoreceptor, postreceptor, and inner retinal cells, respectively. These parameters were then referenced to those of 76 healthy, term-born controls and compared to those of 10 children treated using laser only. RESULTS: In children with treated ROP, every ERG parameter was significantly below the mean in controls. However, these significant ERG deficits did not differ between IVB- and laser-treated eyes. Among children treated using IVB, no ERG parameter was significantly associated with dose or need for subsequent laser. CONCLUSION: Retinal function was significantly impaired in treated ROP eyes. Function in IVB-treated eyes did not differ from that in laser-treated eyes. Functional differences also did not distinguish those IVB-treated eyes that would subsequently need laser for PAR.

Modelling eye lengths and refractions in the periphery.

PURPOSE: To create a simplified model of the eye by which we can specify a key optical characteristic of the crystalline lens, namely its power. METHODS: Cycloplegic refraction and axial length were obtained in 60 eyes of 30 healthy subjects at eccentricities spanning 40° nasal to 40° temporal and were fitted with a three-dimensional parabolic model. Keratometric values and geometric distances to the cornea, lens and retina from 45 eyes supplied a numerical ray tracing model. Posterior lens curvature (PLC) was found by optimising the refractive data using a fixed lens equivalent refractive index ( n eq ). Then, n eq was found using a fixed PLC. RESULTS: Eccentric refractive errors were relatively hyperopic in eyes with central refractions ≤-1.44 D but relatively myopic in emmetropes and hyperopes. Posterior lens power, which cannot be measured directly, was derived from the optimised model lens. There was a weak, negative association between derived PLC and central spherical equivalent refraction. Regardless of refractive error, the posterior retinal curvature remained fixed. CONCLUSIONS: By combining both on- and off-axis refractions and eye length measurements, this simplified model enabled the specification of posterior lens power and captured off-axis lenticular characteristics. The broad distribution in off-axis lens power represents a notable contrast to the relative stability of retinal curvature.

Longitudinal Change of Refractive Error in Retinopathy of Prematurity Treated With Intravitreal Bevacizumab or Laser Photocoagulation.

PURPOSE: To compare progression of myopia and refractive error in former premature infants with retinopathy of prematurity (ROP) treated using intravitreal bevacizumab (IVB) or laser. DESIGN: Retrospective clinical cohort study. METHODS: We identified premature infants with ROP treated using IVB from 2011 to 2020 and compared their longitudinal cycloplegic refraction data to that of infants with ROP treated using laser during the same timeframe. A subset of infants treated using IVB also underwent additional treatment using laser. We included cycloplegic refractions from 789 cumulative visits over a median 3.2 years. We used a linear mixed-effects model with a log decay function to evaluate how refraction changed with age after treatment. RESULTS: In aggregate, the model estimated a significant (P < .001) trend in refraction-from slight hyperopia to relatively more myopic states. However, progression in laser-treated eyes was significantly (P < .001) more rapid, regardless of treatment with IVB. The number of laser spots resulted in increased myopic progression by approximately 0.16 diopters per 100 laser spots. Both ROP stage and zone had a significant effect on myopic progression, with more severe disease resulting in faster myopic progression. Random effects, including individual subject variation with nested variance for left and right eye, accounted for 86.4% of the remaining variance not explained by age and treatment. CONCLUSIONS: Laser treatment for severe ROP increases the trend to severe myopia. In our sample, IVB did not affect myopic progression but did substantially reduce the amount of consequent laser required to treat ROP. The effect of laser persists after accounting for differences in ROP stage and zone.