Automatic refraction and the private ophthalmologist: Dioptron II compared with subjective examination

The author carried out manifest followed by cycloplegic retinoscopy and subjective refraction in 84 office patients. An ophthalmic assistant examined them on the Dioptron II refractor. The results were compared. There was 46% agreement to the nearest +/- .025D for spheres, 51% for cylinders and 44% for spherical equivalents. After cycloplegia, agreement was 47%, 51% and 51% respectively. Axis agreement to the nearest 5 degrees was 46% without and 29% with cycloplegia. Statistical correlation showed this optometer to be most accurate for spheres, less for axes and least for cylindrical powers. In most patients it was more accurate without cycloplegia than with and provided a useful starting point for refraction. It was less useful for children under 8, in elderly, psychiatric and some non-English-speaking patients.