Over the course of last year, we ran a series of four features by Sosena Tang concerning the management of a range of binocular vision presentations. They were deliberately designed to look at the subject from a practical viewpoint, driven primarily by the presenting symptoms. This approach was decided upon as, all too often, teaching in binocular vision has tended towards the theoretical. This often resulted in newly qualified practitioners feeling somewhat daunted when first faced with a patient, usually a child, presenting with a binocular vision concern.

The four articles now are the source material for the interactive exercise and you need to be familiar with their content before attempting the exercise. The four main symptoms covered are as follows:

  • Reduced acuity in one eye – there may be a number of reasons why this is the case. The obvious might be refractive such as unilateral myopia or astigmatism, anisometropic hyperopia. These need correction and, in the case of the last two in particular and depending on the age of the patient, might still show reduced vision after correction due to the presence of amblyopia. There may be a strabismus and, in the case of a microtropia, this may not be apparent on a cover test. In some cases there may be a problem with light reaching the back of the eye, for example due to a ptosis or cataract, or some neurological compromise preventing appropriate image processing.
  • Asthenopia – visual discomfort is very topical at present with much being published concerning digital screen use and its consequences. Asthenopia may often result from the decompensation of a phoria, perhaps with age or changes in visual habit. It may also be indicative of failure of the muscles used to converge or to accommodate (or both) in order to complete any particular visual task.
  • Diplopia – double vision resulting from misalignment of the eyes (and not monocular as may happen, for example, in some cataract states) is usually a troubling symptom and eyes often adapt to reduce the symptom, for example by the suppression of one of the images. As such, diplopia needs addressing and often is indicative of recent changes, some serious such as a sudden onset nerve palsy, and some less so, such as the decompensation of a previously compensated phoria.
  • Cosmetic – cosmesis may not always require any more management than reassurance. A common presentation is the apparent esotropia of an infant which is simply an illusion resulting from their persistent epicanthal folds (pseudostrabismus). More significant cosmetic compromise, often in adults where visual benefit is unlikely, may still need addressing. I remember a case some years ago of a patient with a longstanding large exotropia who, having taken up acting, wanted something done as they felt their appearance was hindering their work prospects.

Please make sure you are familiar with these four articles before attempting the interactive exercise:

Binocular vision walkthrough part 1 - Asthenopia

Binocular vision walkthrough Part 2 – unilateral reduced acuity

Binocular vision walkthrough part 3 - diplopia

Binocular vision walkthrough part 4 – cosmetic appearance

Once you have read through the source material, please attempt the 6 multiple choice questions.