Education

What is an autorefractor keratometer?  You may also hear it referred to as an ARK or AR. and what does it do?  The autorefractor component of the instrument does just that, it’s an automatic objective refraction.  The ARK uses infrared light to refract the eye either by retinoscopy or similar principals. The operation is simple and quick. This data is sometimes sufficient enough to identify 'no change' in the prescription. It also allows the doctor to monitor post-operative refractions until stable. However, it is not reliable enough to prescribe glasses or contacts. Refinement of the prescription is done using subjective techniques by the doctor in the exam room.

This instrument saves a great deal of time.  The keratometer component of the instrument measures the exact radius of curvature of the cornea, which is used in fitting contact lenses.  It also measures the extent and axis of astigmatism. It's important to not get lost just performing the procedure.  While you can report the data you collected, sometimes the lack of data can indicate other things, such as irregularities in the tear film quality and irregularities in pupil size and reaction, sometimes degrees of opacity can indicate cataracts.  

Other useful information that the ARK provides that we may not always take advantage of is the binocular pupillary distance measurement, that can be helpful when setting the phoropter for your doctor. All of the data that it provides can be entered prior to the doctor joining the exam and improves clinic flow.