1. Field of the Invention
The present invention relates to an ophthalmic apparatus which performs examination of an eye to be examined (including measurement of eye characteristics, photographing of an eye portion, and the like).
2. Description of Related Art
In an ophthalmic apparatus such as an eye refractive power measurement apparatus, a corneal shape measurement apparatus, a noncontact tonometer, and a fundus camera, if soil and the like are adhering to optical members such as an examination window and an objective lens, examination results are not obtained (error), or even if obtained, their reliability is lowered. Conventionally, as a remedy for these situations, an instruction manual gives a direction that a protection cap against soil is mounted on the examination window, or a soil check is periodically made. Further, a technique for detecting the soil on the optical members of the apparatus is proposed where a lens cap having a mirror covers the front of the examination window (Japanese Patent Application Unexamined Publication No. Sho61-185247), and alignment light reflected from an eye to be examined is utilized (Japanese Patent Application Unexamined Publication No. Hei7-39516).
Furthermore, also in a case where disturbance light such as sunlight and interior illumination light enters a photo-receiving system inside the apparatus, the examination results are influenced. Therefore, the instruction manual also gives a direction about an installation location of the apparatus.
However, the mounting of the protection cap and the checking of the soil are often forgotten and troublesome. Similarly, the method of detecting the soil by putting the lens cap having the mirror on the front of the examination window is also often forgotten and troublesome. Further, the method of detecting the soil by utilizing the alignment light reflected from the eye cannot be performed in a state where the eye is not placed before the examination.
Furthermore, an operator often does not notice the influence of the disturbance light, and misinterprets abnormality in the examination results and a malfunction as a failure without specifying the disturbance light as a cause for them.