Refractive outcome in eyes with retinopathy of prematurity treated with cryotherapy or diode laser: 3 year follow up.

Aims: To compare the refractive error 1 to 3 years after cryotherapy or diode laser treatment for threshold retinopathy of prematurity.

Methods: Twenty six infants treated with diode laser and 17 infants treated with cryotherapy underwent cycloplegic refraction during follow up.

Results: After 3 years of follow up, 94.1% of patients had myopia (right eye if bilateral) following cryotherapy and 45.5% of patients had myopia following diode laser treatment. The difference between the two proportions was 48.7% (95% confidence interval 17.8 to 80.1, p = 0.004). In the cryotherapy group 55% of patients were highly myopic (> -6.00 dioptres) while in the laser group there were no high myopes.

Conclusions: In the diode laser group there were significantly fewer myopes than in the cryotherapy group up to 3 years after the procedure. There was no trend towards increasing myopia in the laser treated group and the refraction in these eyes stabilised after 1 year. In the cryotherapy group there was a significant increase in the degree of myopia between year 1 and year 3 of follow up (p = 0.02). Diode laser treatment is thought to be as effective as cryotherapy, and has the added benefit of reducing myopia, in the treatment of ROP.