A-A-54205 Stereoscope, Vision TestingThis Commercial Item Description covers a portable, self-enclosed, table top model, stereoscopic vision tester designed and constructed to test for deficiencies in visual acuity, muscle balance, fusion and depth perception at near and far distances.

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A-A-54205

A brow/forehead pest shall be incorporated into the designs that use disposable rest tissues to ensure proper hygienic conditions.

A pointer shall be supplied and an observation/training portal shall be incorporated into the design of the vision tester that will permit easy access to targets for assistance in test administration.

The unit shall have a manual test advance mechanism that will permit testing in either a forward or reverse direction. An automatic (electronic) test advance mechanism with a manual over-ride is also acceptable. The advance mechanism shall include a position/test indicator that will accurately identify the current test in position for viewing. The manufacturer is responsible to identify in the operating instructions the correlation between the indicator test position and test number.

The instrument shall have a name plate securely attached in plain view on its external surface. The name plate shall be legibly and permanently marked with at least the following information:

a. Name or registered trademark of the manufacturer.

b. Type or model number.

c. Serial number.

The unit shall operate from a nominal 115 VAC, 50/60 Hz power supply.

ILLUMINATION.

The power input to the unit shall be controlled through a main switch located on the unit itself. In addition, an automatic illumination activator shall be incorporated into the design that will automatically activate the main illumination only when the test, subject is in proper viewing position. A manual over-ride shall be included which, when desired, will defeat the automatic illumination activator.

All test targets shall be transilluminated.

The illumination source shall be evenly diffused throughout the entire viewing area.

The emitted white background light shall render daylight conditions at a nominal color temperature of 5000 degrees Kelvin. The contrast level between an opaque target and the background shall be a minimum of 98 %.