The ARK-1s is the most advanced model of the auto ref/ keratometer which provides additional measurements such as visual acuity measurements with/without glare test, opacity assessment, and accommodation measurement. The technological advancements of this unit surpass conventional auto refractor / keratometers. The ability to measure central area refraction and wide area refraction up to 6 mm diameter determines the effect of pupil size on refractive power. An artificial intelligence algorithm automatically compensates for the time required for accommodation measurements in cases with slow or weak accommodation. Keratometry measurements are performed with mire rings which reduce lid artifacts. This unit includes 3-D auto tracking and auto shot function for rapid measurements. This new combination generates greater clinical information and increases efficiency.