Abstract
Purpose: :
We have developed a new data analysis algorithm called the automated nystagmus acuity function (ANAF) to automatically assess nystagmus acuity function and compared the ANAF with the well-known expanded nystagmus acuity function (NAFX).
Methods: :
Nystagmus data collected on 30 patients with infantile or fusion maldevelopment nystagmus were analysed using the ANAF and NAFX. The algorithm used all data points during each nystagmus cycle to calculate the ANAF . We also calculated nystagmus acuity function from 6 patients during purposefully inaccurate fixation conditions in order to examine how the nystagmus acuity function was affected by variations of eye position.
Results: :
The ANAF algorithm automatically produced a nystagmus acuity function in a few seconds because it does not need to manually identify foveation eye positions. A structural equation model of the measurement error was used to compare the ANAF and NAFX, both ANAF and NAFX have similar measurement imprecision and relatively little bias. The estimated bias was not statistically significant for either methods or replicates. Variation of foveation eye positions increased during inaccurate fixation conditions; however, nystagmus acuity function measured with either method was not significantly reduced.
Conclusions: :
We conclude that the ANAF is a valid and efficient method for assessment of nystagmus acuity function.
Keywords: nystagmus • neuro-ophthalmology: diagnosis • visual acuity