Esotropia with High AC/A Ratio Clinical Presentation
- Author: Chris Noyes, MD, FAAFP; Chief Editor: Hampton Roy, Sr, MD more...
Parents of the patient may notice an inward or upward deviation of one eye relative to the other eye. The patient may see either a single blurred image or a double image in which one image is clear and one image is blurred.
The age of onset of strabismus should be noted. Family history of strabismus or related diseases is common.
Carefully examine visual acuity in a manner appropriate for the patient's age. For patients younger than 1 year, visual acuity is measured by objective means. For patients aged 1-3 years, subjective methods, such as Allen cards, are used in addition to objective methods. For patients aged 3-5 years, subjective methods, such as Allen cards, tumbling Es, or the letter chart, can be used. For patients older than 5 years, the Snellen alphabet chart almost always can be used. The patient usually will have hyperopia in the range of +3.00 to +10.00 diopters.
Determine stereo acuity using polarized glasses and Titmus test or Randot stereograms.
Check extraocular movements to ensure that eye movements are full.
Measure or estimate angle of deviation. This measurement can be performed most easily by evaluating the centration of the corneal light reflex in each eye, while the patient fixes on objects at distance or near. In some cases, it is possible to perform the alternate cover test. The examiner asks the patient to fix on an object. By alternately covering and uncovering each eye, the examiner can detect a shift in the eye's position with refixation. In esotropia, the uncovered eye turns out to fixate. The angle of deviation is greater with near fixation than at distance and usually is 20-40 prism diopters.
Measure AC/A ratio. Patients with nonrefractive accommodative esotropia have a high AC/A ratio, which results in a deviation measured at near that is significantly greater than that at distance. In contrast, the AC/A ratio is normal (ie, distance and near measurements are the same) in pure accommodative esotropia.
Perform complete eye examination. Examine the anterior segment to assess the cornea, anterior chamber, and lens. Examine the fundus with both direct and indirect ophthalmoscopes. Note the appearance of the macula and the optic nerve.
Perform cycloplegic refraction on all children by using the retinoscope and loose lenses. Cycloplegia is achieved with Mydriacyl 1% if the patient is younger than 1 year; it is achieved with Cyclogyl 1% if the patient is older than 1 year.
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