Patent Number: 7,784,948

Title: Visual acuity testing apparatus

Abstract: A visual acuity testing apparatus capable of performing visual acuity testing under substantially uniform conditions even when a test distance and an installation distance vary has a projection optical unit including a disk whereon a chart is placed, an illumination light source, and variable projection lenses which are moved so as to change an image-forming position and an image size of an image of the chart, an input unit into which an installation distance between the screen and the visual acuity testing apparatus and a test distance between the screen and an examinee are inputted, a projection lens driving unit which moves the variable projection lenses based on the installation distance and the test distance, and a light intensity adjusting unit which adjusts light intensity based on the installation distance and the test distance so that brightness of the chart image falls within a predetermined reference range.

Inventors: Nozawa; Noritsugu (Toyokawa, JP), Kanazawa; Yuichiro (Okazaki, JP), Suzuki; Ryoji (Toyohashi, JP)

Assignee: Nidek Co., Ltd.

International Classification: A61B 3/10 (20060101)

Expiration Date: 8/31/12018