Autorefractors

Excerpt

Manual refraction is the commonly performed optical investigation to understand the errors of refraction, and the procedure has been widely developed. The retinoscopic procedure is time-consuming, subjective, and may not yield accurate results consistently. Not all optometrists or ophthalmologists can accomplish it accurately.

The alternative to this refractometry. Refractometry or optometry is assessing refractive error with a refractometer or optometer instrument. Automated refractors or autorefractors are instruments designed to assess the refractive error and can vary based on the underlying principle.

The last 200 years were focused on automating the process of refraction, but little success was achieved. The last few years have noticed the advent of successful autorefractors, and in the last 30 years, autorefractors have been manufactured which can objectively assess the patient's refractive status with a good level of reliability.

As technology has improved, autorefractors have become reliable and sophisticated, and recently published literature has labeled them more reliable, repeatable, and accurate than subjective retinoscopy. Autorefractors were initially designed by NASA to assess the vision of the pilots. The growing popularity of these devices is due to increased speed, repeatability, accuracy, and repeatability.

In high-volume tertiary eye care setups, autorefractors offer the speed and accuracy for patient assessment in a short period. The autorefractors are based on Scheiner's principle and the optometer principle.

The development of autorefractors can be grouped as early autorefractors and modern autorefractors. The early subjective autorefractors are the Badal optometer and Young's optometer. The early objective autorefractors are based on the optometer principle. The limitations of earlier autorefractors were alignment issues, accommodation problems, and irregular astigmatism.

The activity deals with the general comparison of objective and subjective autorefractors, types of autorefractors, general characteristics of autorefractors, commercially available autorefractors, their indications, and technique of performing autorefractometry, interfering factors, and clinical significance.