Instruments: Adapting the future of refraction

In comparison with most other areas of optometric assessment, the assessment of refractive error has changed surprisingly little for decades. While we have all got used to greater accuracy in fundus imaging (scanning laser technology, autofluorescence), anatomical measurement and monitoring (OCT), surface profiling (topography) and functional testing (electrodiagnosis and algorithm specified automated fields assessment), methods of refraction still rely on techniques using the presentation of lenses that differ by steps of 0.25 dioptres.

Certainly, the move from a trial frame to an automated phoropter head has improved the speed with which lenses can be presented, making subjective comparison easier. Digital control also allowed linkage with other instruments, such as the autorefractor or lens meter, again allowing excellent comparison demonstration and more efficient subjective refraction.