The experimental research of application of the modern small-diameter cryotherapy pen

Objective To assess the effectiveness and safety of cryotherapy on rabbit eyes with cryotherapy pens of different diameter to find the best cryotherapy pen on retinopathy of prematurity.Method The four areas of each rabbit eye was randomly assigned to receive cryotherapy with cryotherapy pens in 1.3 mm、1.5 mm、1.8 mm or 2.0 mm diameter, (the cryotherapy temperature is -60℃and the cryotherapy time is 5 seconds) and then the Results should be analyzed. The other eye was gived cryotherapy according to the retinal response saught by the operationer.Results The damage to retinal is different when the cryotherapy temperature and time are unchanged that the damage area gets larger as the pen diameter gets longer.The cryotherapy time needed by 1.3 mm diameter cryotherapy pen is longer than other three diameter cryotherapy pens when the lightest retinal response could be saught by the operationer.Conclusion 1.5 mm diameter cryotherapy pen is the most suitable for the cryotherapy on retinopathy of prematurity.