Photorefraction is a technique that has been used in the past two decades for pediatric vision screening. The technique uses a digital or photographic camera to capture the examinee‟s retinal reflex from a light source that is located near the camera‟s lens. It has the advantages of being objective, binocular and low cost, which make it a good candidate for pediatric screening when compared to other methods. Although many children have been screened using this technique in the U.S., its sensitivity and other disadvantages make it unacceptable for continued use. The Adaptive Photorefraction system (APS) was developed at the Center for Laser Applications (CLA) at the University of Tennessee Space Institute (UTSI) to correct the problems in the existing PS devices. APS was designed to determine quantitatively binocular refractive errors and strabismus and to accomplish these tasks objectively, without the need of medical professionals, and it is capable of performing these objectives and reporting the digitally recorded results within one- to-two minutes. In this dissertation, two APS prototypes were constructed, and measurements were performed using both an artificial eye and human subjects. Binocular measurements of refractive error were determined, and the effects of the variation of pupil-size and gaze angle were determined. After initial corrections for ocular scattering effects, measurement of the binocular refractive error of forty human subjects was achieved, and in the myopic region with uncertainty of the method was 0.6 diopter. Ocular alignment determinations were achieved, and using a novel cover-uncover test, strabismus detection was demonstrated.

This work is dealing with design of the systém for measuring dynamics of the vergence and accommodation. Vergence accommodation synkinesis is a complex process controlled by various mechanisms in CNS. Deviations from physiological state of the vision process are projected to course of the vergence accommodation curves and is possible the quantitative and qualitative evaluation. For this purpose was designed the measuring system Ir.M.A. (Infrared Measurement of Accommodation). The system uses high-speed videometric device for determination of the relative vergence and relative accomodation of the eyes. Stimulation of the patient's eyes is performed by the standardized jump change of the fixation object distance. The object is reconstruted by holographic method. Measured videosequences are processed by the image analysis. Results of the image analysis are courses of the vergence and accommodation curves depending on time and characteristics of the curves. System is designed for using in clinical practice where it could be used as screening instrument for diagnostics of the oculomotor system disorders.

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