| 摘要 |
A visual examination apparatus for administering a photostress recovery test. The photo pigments of the cones of the subject eye are conditioned to a steady state by exposure to a dim light which retro-illuminates an optotype. The size of the optotype is related to the visual acuity of the subject eye. A bright light source of repeatable duration and intensity and spectral distribution of energy is directed to bleach the photo pigments of the cones of the macula. A common switch triggers the flash and starts a digital timer. After the flash, a different optotype of the same size as the initial one is substituted therefor. When the subject eye recovers from the dazzling flash sufficiently to detect the different optotype, the timer is stopped. The length of time required for the cones of the macula to regenerate photo pigment is dependent upon whether the cones are normal and on their apposition to the retinal pigment epithelium. The recovery time period indicates a normal or abnormal condition of the cones of the macula.
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