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Photorefraction with a catadioptric lens
Author(s) -
Norcia Anthony M.,
Zadnik Karla,
Day Susan H.
Publication year - 1986
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.1986.tb06939.x
Subject(s) - dioptre , refractive error , pupil , lens (geology) , catadioptric system , optometry , optics , sensitivity (control systems) , flash (photography) , ophthalmology , computer science , medicine , physics , visual acuity , engineering , electronic engineering
Kaakinen (1979) presented a method of measuring refractive error and ocular alignment by simultaneous photography of corneal and fundus reflexes. As presented, the technique was unable to detect refractive errors of less than 2–3 diopters (Howland 1980; Kaakinen 1979). We demonstrate that the use of a catadioptric lens and a long working distance can improve sensitivity to less than 1.0 D. Refractions of a model eye, an accommodating eye and ametropic eyes indicate that refractive errors greater than 0.75 .D are readily detectable. The improvement in sensitivity achieved by the present system is attributable to a reduction of the angle between the flash source and the entrance pupil of the photorefractor.