Myopia of prematurity

Editor,—Fielder and Quinn1 have provided an interesting hypothesis and speculation on the origin of myopia in premature infants’ eyes following treatment for ROP. However, they have overstated the strength of the evidence in their opening statement that ‘. . . clinical research has shown that the degree of myopia is significantly less following laser therapy when compared with cryotherapy for severe ROP.’ The three references quoted contain evidence only from historical comparison groups, raising questions about the strength of the evidence for this conclusion.2-4

The reports describe the incidence4 or severity2 of myopia in two studies which compared laser with cryo treated ROP. Patient allocation of these 66 infants to the two treatments was not random, with the earlier historical comparison groups receiving cryotherapy. The third report3 describes 13 laser treated infants with no comparison group. Infants who lost vision were largely unreported. (In our own literature search a fourth report5 describes myopia outcomes in 17 infants treated with cryotherapy and 26 infants treated with laser therapy, but these are probably included among the infants reported by Algawi et al …