Refractive outcomes following yttrium aluminum garnet laser (532 nm green laser) in severe retinopathy of prematurity

PURPOSE: To assess the refractive outcomes in eyes with severe Retinopathy of prematurity (ROP) after treatment with the frequency-doubled neodymium-doped yttrium aluminum garnet (Nd-YAG) laser 532 nm (green laser) at 1–2 years of age and compare with eyes that underwent spontaneous regression of ROP and to identify the risk factors associated with the refractive outcomes in laser-treated eyes with severe ROP. METHODOLOGY: Infants who underwent laser treatment with green laser were enrolled in Group 1 and those who had spontaneous regression of ROP were enrolled in Group 2. All these children underwent a visual assessment, refraction using 1% cyclopentolate eye drops and indirect ophthalmoscopy at 1–2 years of age. Data regarding the gestational age, sex, birth weight, inborn (born in our institution) or outborn (born outside and referred to us), stage and zone of ROP and laser spots given were obtained from the treatment records. Data were analyzed using SSPS 19.0 software for Windows (SSPS Inc., Chicago, Illinois, USA). RESULTS: A total of 102 infants were enrolled, 51 in each group. Visual acuity ranged from 0.25–1 cycles per cm in both groups. Spherical equivalent (SE) ranged from − 8.25 D to + 5.50 D in Group 1 and −1.00D to +4.00D in Group 2. Group 1 had an incidence of 23.5% Myopia and 33.4% Astigmatism which was significantly more than Group 2. The linear regression model predicted a decrease in the SE by 0.658D if the number of laser spots increased by 1000 (P < 0.001). No other risk factors (gestational age/birth weight) were found to have a significant association with refractive errors in the lasered ROP group. CONCLUSIONS: Eyes with laser-treated severe ROP are frequently associated with myopia and astigmatism when compared to spontaneously regressed ROP. The number of laser spots delivered has a direct association with the amount of refractive error.