The influence of retinopathy of prematurity on ocular growth

Purpose Retinopathy of prematurity (ROP) stage 3 eyes that require treatmen t have a greater tendency to myopia compared with eyes with mild ROP. As th e mechanisms controlling this myopia are as yet ill understood, we undertoo k this study to investigate what effect the initial stage of ROP and modali ty of treatment had on ocular growth. Methods Eighty-five children were assessed. All children were refracted and underwent 'through-the-lid' biometry using the Zeiss Humphrey biometer 820 . The printout obtained was then recorded on video so that the scan could b e captured on computer for formal calibration and measurement by a masked o bserver. Differences in the distribution of variables between the stages of ROP were analysed by one-way analysis of variance, non-parametric Kruskal- Wallis one-way analysis of variance or Mann-Whitney U-test as appropriate. Results A difference between the stages of ROP was apparent only for poster ior segment length (PSL) (R: p = 0.03; L: p = 0.05) and a borderline differ ence for anterior chamber depth (ACD) (R: p = 0.06; L: p = 0.06). However, if stage 3 was divided into categories of treated and untreated, axial leng th (AW achieved borderline significance (R: p = 0.07; L: p = 0.05) but with no difference between laser-treated and the other stages for AL. Lens thic kness (LT) also appears to be influenced by type of treatment (R: p = 0.06; L: p = 0.13). Myopia was associated with stage 3 (R + L: p = 0.0001) and i f stage 3 was subdivided the significance was maintained only for the laser - and cryotherapy-treated eyes. Conclusions Laser-treated eyes were less myopic than those treated with cry otherapy. AL does not explain all the myopia found in stage 3 treated eyes. The study confirms the tendency towards anterior segment arrest in stage 3 ROP.