The disclosure herein describes controlling focal parameters of a head mounted display based on an estimated user age to account for increasing likelihood of presbyopia as user age increases. The head mounted display uses eye tracking sensors to collect ocular metric data associated with ocular features of a user's eye and a user age estimate is calculated based on analysis of the ocular metric data using a machine learning algorithm and an ocular metric data set. Further, a confidence value of the user age estimate is calculated based on the analysis of the ocular metric data. Then, focal parameters of the visual display of the head mounted display are controlled based on the user age estimate and confidence value. The described focal control method provides a seamless, automated way for a head mounted display system to adjust settings to provide a sharp, in-focus user experience for users of all ages.