eMedicine Specialties > Ophthalmology > Extraocular Muscles

Esotropia, with High AC/A Ratio

Author: Christopher T Noyes, MD, Private Practice, Texas Family Medicine
Coauthor(s): Raghav R Gupta, MD, Consulting Staff, Department of Ophthalmology, Vista Ophthalmology, Medical Center of Plano, and Presbyterian Hospital of Plano
Contributor Information and Disclosures

Updated: Nov 7, 2007

Introduction

Background

Strabismus is a misalignment of the eyes such that both eyes are not directed simultaneously at the same object. Esotropia is a type of strabismus characterized by an inward deviation of one eye relative to the other eye. The accommodative convergence/accommodation (AC/A) ratio gives the relationship between the amount of convergence (in-turning of the eyes) that is generated by a given amount of accommodation (focusing effort). Esotropia with high AC/A ratio (also termed nonrefractive accommodative esotropia) combines a high AC/A ratio with low hyperopia or even myopia. Amblyopia (reduced visual acuity due to an abnormal visual experience early in life) frequently develops if the condition remains untreated.

Race

No racial predilection exists.

Sex

No sex predilection exists.

Age

Esotropia with high AC/A ratio presents by the age of 2 years.

Clinical

History

  • 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.

Physical

  • 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 exam.
    • 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.

More on Esotropia, with High AC/A Ratio

Overview: Esotropia, with High AC/A Ratio
Differential Diagnoses & Workup: Esotropia, with High AC/A Ratio
Treatment & Medication: Esotropia, with High AC/A Ratio
Follow-up: Esotropia, with High AC/A Ratio
References
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References

  1. Beers MH, Berkow R. The Merck Manual of Diagnosis and Therapy. 1999.

  2. Berson FG. Basic Ophthalmology for Medical Students and Primary Care Residents. 1993.

  3. Catalano RA, Nelson LB. Pediatric Ophthalmology: A Text Atlas. 1994.

  4. Helveston EM, Ellis FD. Pediatric Ophthalmology Practice. 1980.

  5. Kunimoto DY, et al. The Wills Eye Manual: Office and Emergency Room Diagnosis and Treatment of Eye Disease. 2004.

  6. Wright KW, et al. Pediatric Ophthalmology and Strabismus. 1995.

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Further Reading

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Keywords

nonrefractive accommodative esotropia, accommodative esotropia, accommodative convergence/accommodation ratio, strabismus, eye misalignment, misalignment of eyes, inward deviation of eye, inward eye deviation, hyperopia, farsightedness, myopia, nearsightedness, amblyopia

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Contributor Information and Disclosures

Author

Christopher T Noyes, MD, Private Practice, Texas Family Medicine
Christopher T Noyes, MD is a member of the following medical societies: American Academy of Family Physicians, American Medical Association, and Texas Academy of Family Physicians
Disclosure: Nothing to disclose.

Coauthor(s)

Raghav R Gupta, MD, Consulting Staff, Department of Ophthalmology, Vista Ophthalmology, Medical Center of Plano, and Presbyterian Hospital of Plano
Disclosure: eMedicine Honoraria Other

Medical Editor

Gerhard W Cibis, MD, Director of Pediatric Ophthalmology Service, Clinical Professor, Clinical Professor, Department of Ophthalmology, Department of Ophthalmology, University of Kansas; Director, Children's Mercy Hospital, University of Missouri at Kansas City
Gerhard W Cibis, MD is a member of the following medical societies: American Academy of Ophthalmology, American Ophthalmological Society, and Association for Research in Vision and Ophthalmology
Disclosure: Nothing to disclose.

Pharmacy Editor

Simon K Law, MD, PharmD, Assistant Professor of Ophthalmology, Jules Stein Eye Institute; Chief of Section of Ophthalmology Surgical Services, Department of Veterans Affairs Healthcare Center, West Los Angeles
Simon K Law, MD, PharmD is a member of the following medical societies: American Academy of Ophthalmology, American Glaucoma Society, and Association for Research in Vision and Ophthalmology
Disclosure: Nothing to disclose.

Managing Editor

J James Rowsey, MD, Director of Corneal Services, St Luke's Cataract and Laser Institute, Florida
Disclosure: Nothing to disclose.

CME Editor

Lance L Brown, OD, MD, Ophthalmologist, Affiliated With Freeman Hospital and St John's Hospital, Regional Eye Center, Joplin, Missouri
Disclosure: Nothing to disclose.

Chief Editor

Hampton Roy Sr, MD, Associate Clinical Professor, Department of Ophthalmology, University of Arkansas for Medical Sciences
Hampton Roy Sr, MD is a member of the following medical societies: American Academy of Ophthalmology, American College of Surgeons, and Pan-American Association of Ophthalmology
Disclosure: Nothing to disclose.

 
 
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