The effect of off-the-visual-axis retinoscopy on objective refractive measurement.
OBJECTIVE
To determine the effect of off-axis retinoscopy on objective refractive measurement.


METHODS
Prospective experimental study.


METHODS
Eight volunteers underwent cycloplegic retinoscopy of their right eye on-the-visual-axis, and 5, 10, 15, and 20 degrees off-the-visual-axis in adduction. A single masked examiner performed all retinoscopy with random order of the patient and axis refracted.


RESULTS
The average spherical retinoscopic value at 0, 5,10,15, and 20 degrees of off-axis alignment was -0.40, -0.90, -1.00, -1.38, and -1.80 diopters, respectively. The average spherical equivalent retinoscopic value obtained for each of the above positions of eye alignment was -0.02, -0.59, -0.45, -0.64, and -0.98 diopters, respectively. The induced cylinder power increased by an average of 3% for each degree of off-axis retinoscopy, though the axis of the cylinder was not predictable.


CONCLUSIONS
Objective refractive measurement by retinoscopy is significantly altered by off-the visual-axis retinoscopy. The induced error may be clinically important even with small degrees of eccentricity.
Jackson
David W
DW
Cullen Eye Institue, Baylor College of Medicine, and Department of Ophthalmology, Texas Children's Hospital, Houston, 77030, USA.
Paysse
Evelyn A
EA
Wilhelmus
Kirk R
KR
Hussein
Mohamed A W
MA
Rosby
Gina
G
Coats
David K
DK
D000328:Adult; D003519:Cyclopentolate / Q000008:administration & dosage; D004359:Drug Therapy, Combination; D006801:Humans; D009184:Mydriatics / Q000008:administration & dosage; D010656:Phenylephrine / Q000008:administration & dosage; D011446:Prospective Studies; D011680:Pupil / Q000187:drug effects; D012029:Refraction, Ocular; D012030:Refractive Errors / Q000175:diagnosis*; D015203:Reproducibility of Results; D042262:Retinoscopy / Q000592:standards*; D014331:Tropicamide / Q000008:administration & dosage
D009184:Mydriatics; D010656:Phenylephrine; D003519:Cyclopentolate; D014331:Tropicamide