Infrared light is commonly used in the eye tracker because it eliminates the influence of ambient illumination and improves the discrepancy between the pupil and the white of the eye. A common eye tracker uses a normal image sensor and image processing algorithm. This chapter introduces three versions of the single-chip eye tracker with the smart complementary metal-oxide-semiconductor image sensor pixels. It proposes the single-chip eye tracker that generates the address for the center point of the pupil, that eliminates the glint effect and generates the digital address for the center of the pupil and the single-chip eye tracker that has a 512 × 256 improved smart pixel array. The chapter examines an eye-tracking algorithm and architecture that can eliminate the effect of glints. It describes circuit implementation and presents the simulation and experimental results. The introduced eye trackers are used as a pointing device in conjunction with a head-mounted display and an input device for the handicapped.