Abstract
Mathematical models of accommodation-vergence and its interaction have been developed using feedback control theory by Hung et al (1992)1 and Schor et al (1986)6 to study the behaviors of accommodation and vergence systems. Sensitivity analysis is used to determine the output change of a model in response to changes in its parameter values. A mathematical model of accommodation-vergence (Schor's model) was created using Simulink, Matlab ® and sensitivity analysis was performed. The results were then compared with the sensitivity analysis done by Hung (1994)2 on his own model. The nominal behavior of the model was determined using the parameter values suggested by Schor (1986)6. The behavioral changes were noted by changing the parameter values in two different ways: 1) gains of each parameter were changed in 0.1 times and 10 times (to calculate sensitivity coefficients) and 2) state variables (stimulus to accommodation and vergence) were changed (to calculate sensitivity function). The results of these analyses found crosslink gains were the most sensitive parameter in the model as evident from the sensitivity coefficient calculations. This was similar to results obtained from Hung (1994)2. The plant gains of accommodation and vergence were the next most sensitive parameter in Schor's model. Unlike Hung's model where the tonic system was shown to be a moderately sensitive parameter, the tonic system of the Schor's model was not a sensitive parameter which was evident from both sensitivity coefficient and sensitivity function calculations. These results will be discussed along with clinical implications.
Meeting abstract presented at OSA Fall Vision 2012