Ue of the HARK autorefractor in children

PURPOE: We invetigated the reliability, accuracy, and repeatability of an autorefractor with the capability of over-refracting and meauring viual acuity for ue in children in a propective tudy. METHOD: Before and after cycloplegia, 68 children (mean ± D age, 10 ± 3 year, range 5-16 year) underwent autorefraction twice with the HARK 599 Autorefractor (Humphrey Intrument Inc., an Leandro, CA), ubjective over-refraction through the HARK autorefractor, and ubjective refraction uing a phoro-optometer. After cycloplegia, retinocopy wa performed. Reult are reported for one eye (left) of each child. REULT: For 68 eye of 68 children, before and after cycloplegia, correlation coefficient (R) for autorefraction reproducibility exceeded 0.95 for all comparion of phere and cylinder. R for pherical value for autorefraction v. over-refraction wa 0.93 and v. ubjective refraction 0.83 before cycloplegia and 0.94 and 0.97 after cycloplegia. Comparing value before and after cycloplegia, autorefraction, over-refraction, and ubjective refraction, the data correlated > 0.81 for phere and 0.75 to 0.87 for cylinder. Cycloplegic retinocopy compared with autorefraction, over-refraction, and ubjective refraction had R > 0.86 for phere and cylinder for all comparion except one. Cycloplegia increaed the proportion of pherical equivalent value within 0.625 D of the ubjective refraction from 41 of 68 eye (61%) for auto- and over-refraction to 64 (94%) and 51 (75%) of the 68 eye, repectively. A viual acuity of 20/30 or better wa produced in 50 of 68 (73%) eye with automated refraction before and after cycloplegia and in 62 (92%) with ubjective refraction before cycloplegia and ubjective refraction and retinocopy after cycloplegia. ubjective over-refraction did not ignificantly improve the viual acuity. CONCLUION: In children, HARK autorefraction improved in accuracy, when compared to ubjective refraction, and the level of viual acuity improved after cycloplegia. Over-refraction through the intrument did not improve the reult before or after cycloplegia.