Subjective refraction and prescribing styles used by UK optometrists.

Abstract

Purpose: To investigate the methods of subjective refraction and prescribing used by UK optometrists in routine eye examinations.

Methods: Following a pilot study of 12 observed refractions conducted by nine optometrists, a questionnaire consisting of simple questions regarding methods used together with conditional response clinical vignettes was constructed. Paper copies were distributed to UK optometrists attending continuing professional development (CPD) courses, in addition to an online version.

Results: Two hundred and four completed questionnaires were gathered from respondents with a mean experience of 16 years (SD, 12 years). Poor technique was defined as likely to contribute to or cause a recheck according to a previous study. Poor techniques seen included visual acuity (VA) not being measured to a full threshold level by 93% of respondents, 37% (55/149) prescribing a small oblique cylinder to an asymptomatic patient and 39% (71/183) making just one subjective change to the axis of a -1.00 D cylinder from their starting prescription before prescribing that axis change to a mildly symptomatic patient. The risk of over-plusing was identified, with 28% (N = 46) of respondents happy to prescribe a full objective +0.50 DS change to a patient with no distance-related symptoms. Symptoms, prescription change and VAs are often not reconciled, with 43% (82/189) of respondents reporting being happy to prescribe a full subjective change of -2.00 DS together with -0.75 DC for a 72-year-old patient for a relatively small VA improvement of 6/15 to 6/7.5.

Conclusions: Poor subjective refraction and prescribing techniques were identified; limited measurement of VA to full threshold, risk of over-plusing/under-minusing, limited cylinder power and axis techniques and symptoms often not reconciling with changes in prescription and improvements in VA were observed. The objective prescription, particularly as determined by autorefractors, holds an exaggerated influence over some optometrists. These are elements of everyday optometry, yet require greater emphasis in CPD.