Table 2

Refractive state following preterm birth with and without retinopathy of prematurity (ROP)

Study	BW/GA	ROP	Age	Refractive errors
EXPRESS25	<27 weeks	73.7% (20.4% treated)	30 months	25.6%—all
CRYO-ROP Study26	<1251 g	All reached threshold (82.5% bilateral)	3.5 years	Moderate myopia (≥2 D to <6 D): Treated eyes 20.5% Untreated eyes 15.5% High myopia (≥6 D): Treated eyes 37.7% Untreated eyes 27.2%
ETROP27	<1251 g	High-risk prethreshold	6 years	Astigmatism ≥52% in all treated eyes High astigmatism ≥23% in all treated eyes
ETROP23	<1251 g	High-risk prethreshold	6 years	Myopia ≥65% in all treated eyes High myopia≥35% in all treated eyes
Larsson and Holmström20	<1501 g	39%	10 years	Moderate myopia 3.8% Moderate hypermetropia 4.2% Astigmatism 21%
O'Connor et al22	<1701 g	50%	10–12 years	Mild myopia 15.2% Moderate myopia 3.8% Moderate hypermetropia 6.6%

Refractive errors are defined (unless otherwise stated) as mild myopia <3.0 dioptre sphere, moderate ≥3 dioptre sphere, high myopia >5.0 dioptre sphere, moderate hypermetropia ≥3.0 dioptre sphere, astigmatism ≥1.00 dioptres and high astigmatism ≥2.00 dioptres.
BW, birth weight; D, dioptre; GA, gestational age.