The Safir Ophthalmetron was tested clinically at the Massachusetts Eye and Ear Infirmary. The refractive error of normal eyes was determined by two separate retinoscopies, by subjective refraction, and by the Ophthalmetron. Results of each method were compared statistically.
The Ophthalmetron proved to be accurate. The spherical equivalents, spherical power, and the axis showed insignificant differences between the various refractive methods. The Ophthalmetron read greater astigmatism than did the refractionists, but its clinical significance was doubted.
Effectiveness of the machine was limited by pupil size, patient cooperation, and technician accuracy.
Floyd RP, Garcia G. The OphthalmetronA Clinical Trial of Accuracy. Arch Ophthalmol. 1974;92(1):10-14. doi:10.1001/archopht.1974.01010010014004