Simulating and Compensating for Eye Motion Blur with Eye Tribe

Nystagmus is a periodic, involuntary eye condition. It is characterized by the smooth pursuit of the eye away from the target location followed by a quick saccade back to the target location. Nystagmus is also called “dancing eyes” as the eye movements appear pendular or jerky to an observer. Everyone has nystagmus. Trying to fixate on objects far in your periphery will produce nystagmus-like movements, as will some drugs. Sobriety tests often examine the gaze of one’s eyes, looking for alcohol-induced nystagmus. Nystagmus is either physiological or pathological [1]. The former case involves gaze-evoked nystagmus or optokinetic nystagmus (which is induced in the observer). The latter includes both acquired and congenital nystagmus. Interestingly, those with congenital nystagmus generally adapt to the condition and, depending on the severity of the nystagmus, the vision may not be affected greatly. However, a person with acquired nystagmus can suffer from oscillopsia, which is the apparent feeling that the world is spinning; this consequence of nystagmus can lead to further complications, such as vertigo [2]. It is thought that 1 in 1,000-2,000 people are affected by congenital and acquired nystagmus [3]. Those with nystagmus generally develop compensatory strategies to reduce the blurring and other consequences of their eye motions. These patients commonly tilt their head in an orientation that puts their eyes in a position that minimizes the effect of their nystagmus [1]. Some patient’s nystagmus disappears altogether in specific positions, but for most people (especially those with acquired nystagmus), the consequences persist. There is no definitive cure for nystagmus. It is possible to treat it with surgery, but results vary from patient to patient. In many situations, people with this condition could benefit greatly from enhanced visual acuity. A temporary solution involving head-mounted displays (HMDs) and eye tracking for sensitive situations such as reading or writing may be possible. By actively monitoring the gaze of the eyes in real time, a head mounted display could react by shifting the displayed image of the real world to counteract the effects of nystagmus. This would result in an image that appears stabilized to the observer, thus increasing the individual’s visual acuity. A necessary requirement in developing such a visual compensation system is access to people exhibiting nystagmus. Fortunately, it is possible to induce optokinetic nystagmus in a person with normal vision using various graphics on displays [4]. In one such experiment, a 1D spatially varying sinusoidal pattern is projected onto a screen opposite an observer (see Fig. 1). The pattern moves either left tor right at a constant angular velocity, so a certain number of different colors / shades pass a fixed point on the screen in a given amount of time. The observer is then asked to count the number of times a particular color passes the center of the