Hand-held ophthalmological instrument for measuring corneal radius of curvature

摘要

The instrument uses an optical projection system (31,32) to first project a pair of light beams to cornea (1) on to a central area of the surface to be measured and notes the direction of reflection from these. A second pair of light beams (35,36) is then projected on to a second area of the cornea, outside the first but on the same axis. An objective lens (204) transmits both first and second reflected beams to a measuring system (40) where the angle difference is detected, from which a microprocessor (60) calculates the curvature. The system requires no movement of the patient's eye but accurately measures the curvature of the central and circumference area of the cornea.