Portable Autorefractor. Hand Held Automated Refraction, Mobile/Portable/ Perfect for Children, Full Range of Measurement for Refraction Readings, Minimum Pupil Size 2.5mm. Benefit from the simplicity and ease of the World’s First Hand-Held Autorefractor. Well respected history and reputation for accuracy, reliability and performance Share the Retinomax between offices or between rooms. With no wires to limit, you can use it virturally anywhere retinomax has full measurement range and advanced measurement modes. Readings are taken the instant that alignment and focus is achieved. Perfect for Children. Elimination of the chin rest and the added melody function makes it easy to take their measurements.