Abstract: A process to control the extent of photocoagulation of the retina wherein light reflected from discrete portions (Ti) of the retina (75) in the eye is projected by a lens system (82) to individual photodiodes (DI) in an array (85) to generate electrical signals related to the light intensity reflected from a corresponding portion (Ti) on the retina (75) being treated. A change in the reflectance of any discrete portion (Ti) of an area on the retina relative to the reflectance of any discrete portion of the area on the retina actuates a control mechanism associated with laser (22). Upon a change to a threshold reflectance or a maximum rate of change in reflectance, a control apparatus (90) automatically adjusts parameters of treatment including power (22), focus (25) or sighting (102, 104).

Abstract: Apparatus to control the extent of photocoagulation of the retina wherein light reflected from discrete portions (T.sub.i) of the retina (75) in the eye is projected by a lens system (82) to individual photodiodes (D1) in an array (85) to generate electrical signals related to the light intensity reflected from a corresponding portion (T.sub.i) on the retina (75) being treated. A change in the reflectance of any discrete portion (T.sub.i) of an area on the retina relative to the reflectance of any discrete portion of the area on the retina actuates a control mechanism associated with laser (22). Upon a change to a threshold reflectance or a maximum rate of change in reflectance, a control apparatus (90) automatically adjusts parameters of treatment including power (22), focus (25) or sighting (102, 104).