Objective Visual Acuity Measurement Using Suppression of the Optokinetic Nystagmus (OKN).

Clinical Application of Objective Visual Acuity Measurement Using Suppression Method to Inhibit Optokinetic Nystagmus (OKN).

Suppression of the optokinetic nystagmus when a target is perceived can be applied to assess visual acuity objectively. Our aim is to establish prediction intervals for this optokinetic nystagmus suppression test (Speedwheel Test, SW) so that SW acuity may be used to estimate Snellen acuity (FrACT- C and -E) in the clinic in adults and children unable to cooperate in other acuity testing.

In this prospective single center study subjects aged at least 4 years underwent testing of visual acuity with SW, Landolt-C and Tumbling-E symbols (Freiburg acuity test: FrACT-C, FrACT-E). Prediction intervals are to be established for SW compared to FrACT-C or -E and for FrACT- E compared to FrACT-C.

Inclusion Criteria:

• able and willing to perform the test

Exclusion Criteria:

• under 4 years of age
• unable or unwilling