Ophthalmologic curvature measuring device and method to conjointly measure a central and peripheral portion of a curved surface

摘要

An ophthalmologic curvature measuring device measures the shape of a central portion and the shape of a peripheral portion of a curved surface such as a cornea of the eye or contact lenses. The measuring device has a small size and is capable of being hand held during measurement. A plurality of light beams are first projected onto the cornea and corneal periphery of the eye. A first projection unit then projects a first mark onto a first region of the subject eye while a second projection unit projects a pair of second marks onto a second region of the subject eye. An objective lens transmits reflected images of the first and the second marks to a measurement unit which measures the second marks at first and second timings. A displacement detecting unit then detects relative angular displacement of the measured first and second positions of the second marks about an optical axis and a calculation unit calculates the second region of the subject curved surface from the relative angular displacement detected by the displacement detecting unit.