Optometrist core subject 3 : Visual function

Last week we began looking at core subject 3 of the listed GOC core competencies for entry level optometrists. There is much in this area which was directly assessed under the old pre-registration qualification exams.

Routine refraction is obviously a key element in optometrist competency. Under the new scheme evidence of having experience in successfully refracting a variety of patients depends primarily upon a trainee keeping an up-to-date log book. Any patients of particular interest, such as those with unstable accommodation or complex refractive errors, are better recorded on a separate list so if evidence of experience is needed, record cards may be produced.

Other competencies refer to elements which were previously assessed under the label 'Investigative techniques' (such as the ability to assess a patient's colour vision and to determine whether it achieves the standards required by various vocational groups). A full and comprehensive list of visual standards relating to specific occupations may be found on the Association of Optometrists website (www.assoc-optometrists.org/services/visual).

There are also competencies relating very much to dealing with the visually impaired. For example, the ability to assess patients with impaired visual function and the ability to advise visually impaired patients about their impairment, disability or handicap. Much of this area is covered in this issue of Optician.

Another competency covers an area which previously was usually incorporated into the old binocular vision PQE - the ability to assess children's visual function using appropriate techniques.

The pilot trial of the assessment based pre-registration year which ran throughout last year showed up lack of experience with very young patients as being an issue and this competency was one of several where many had problems achieving a level considered satisfactory among assessors.

Although many practices are able only to offer a straightforward Snellen style acuity chart, the proliferation of computerised charts and improving practice equipment in general means that all should be aware of the tests best used to assess children's vision.

Assessing Children's Visual Function

One of the most important aspects of acuity testing for the optometrist is detection of significant interocular acuity differences. Binocular acuity values allow the optometrist to rule out a gross visual impairment, but monocular visual acuities provide much greater insight into the state of the developing visual system. During early infancy, transient interocular acuity differences are not uncommon, but persistent interocular acuity differences beyond the first year of life are cause for concern and require further investigation. They may signal amblyopia, other pathology or anisometropia.

Optometrists must also be able to judge whether acuity between visits or after treatment or spectacle correction has significantly changed.