M. Cleary et Cm. Thompson, Diagnosis of eccentric fixation using a calibrated ophthalmoscope: defining clinically significant limits, OPHTHAL PHY, 21(6), 2001, pp. 461-469
Visuscopy and other ophthalmoscopic methods are widely applied in the asses
sment of fixation behaviour in amblyopia, although the reliability and inte
r-examiner variability of this test has not been established. Typically ecc
entric fixation is diagnosed solely on the basis of retinal position, but t
his fails to address the accompanying sensorimotor adaptations. A double-bl
ind (masked) trial of a paediatric population was undertaken (n = 30, age r
ange 3 years 9 months to 11 years, mean 5.6 +/- 1.5 years), involving three
examiners applying a detailed protocol. The criteria for eccentric fixatio
n were established from the non-amblyopic eyes. The most reliable criterion
for the diagnosis of fixation was established from the results of the stud
y. No single parameter proved 100% reliable, and amplitude showed greatest
inconsistencies. It is recommended that a consensus of at least three param
eters from position, zero retinomotor point, principal visual direction and
percent foveation is required to diagnose the fixation status reliably. (C
) 2001 The College of Optometrists. Published by Elsevier Science Ltd. All
rights reserved.