The assessment of smooth tracking dysfunction

The two main techniques for recording eye movements, electro-oculography (EOG) and infrared reflection (IR), are discussed and compared. Methods of quantifying eye movement dysfunction are also reviewed and contrasted. It is concluded that EOG and IR recordings both contain information not present in the other and that both methods will continue to be useful. Similarly, although the root-mean-square (RMS) and the signal-to-noise ratio (S/N) indices are algebraic functions of one another, the function is not linear and one or the other may be more appropriate to a particular application.