iTrace aberrometry - Identifying occult imperfections in the visual system

Abstract

Visual acuity is the sum of qualitative and quantitative factors. A combination of both determines the final visual acuity. The quality of vision (QoV) can be easily assessed by documenting objectively the higher-order aberrations or by using subjective questionnaires available. The QoV is an integration of varied optical and neural factors. Similarly, the quantity of vision is documented by measuring uncorrected and best-corrected distance visual acuities. Optical aberrations are defect in a lens or a mirror prevents light rays from being focused at a single point and results in a distorted or blurred image. Moreover, they are the departure of the performance of an optical system from the predictions of paraxial optics. The QoV is primarily affected by both higher- and lower-order optical aberration. Aberrometers are the most vital instruments used for estimating optical aberrations so that a more comprehensive understanding of optical error can be quantified and corrected. A variety of aberrometers with different principles are available, such as Ray Tracing, Hartmann-Shack, Tscherning, and automatic retinoscopy. In this review, our prime focuses on Ray Tracing aberrometer, iTrace. This review will help all the ophthalmologists including residents and fellows learn the principle, features, and clinical applications of iTrace. The system integrates corneal topography with wavefront aberrometry, which has the unique feature of revealing the internal aberrations of the eye by subtracting the corneal aberrations from total aberration. It is the investigation of choice in the today's era considering patient satisfaction and visual outcomes, postpremium intraocular lens implantations.

Keywords

• corneal topography
• itrace
• ray tracing aberrometer
• wavefront aberrometry