PHOTOMETER FOR MEASURING THE SCOTOPIC CANDLEPOWERS OF SELF-LUMINOUS OPHTHALMIC TEST OBJECTS

Area of Science:

• Photometry
• Ophthalmology
• Radiological Physics

Background:

• Measuring feeble light sources is essential for visual field testing.
• Radium paint spots are used for plotting the dark-adapted visual field.
• Existing photometers may lack the sensitivity for these applications.

Purpose of the Study:

• To describe a novel photometer for measuring scotopic candlepowers of very feeble light sources.
• To calibrate small radium paint spots used in visual field studies.
• To validate the photometer's adherence to the scotopic visibility curve.

Main Methods:

• Development of a sensitive photometer.
• Calibration of radium paint sources (2-3 mm diameter) with candlepowers in the range of 10(-9) candle.
• Testing with color filters and spectral transmission curves to verify scotopic measurement.

Main Results:

• The photometer successfully measures scotopic candlepowers down to approximately 10(-9) candle.
• The instrument is suitable for calibrating radium paint light sources.
• Measurements align with the scotopic visibility curve of the human eye.

Conclusions:

• The described photometer provides accurate measurements of feeble light sources.
• It is a valuable tool for calibrating instruments used in ophthalmological research.
• The photometer's performance is validated against the standard scotopic visibility curve.