AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Background

Esotropia is a type of strabismus or eye misalignment. The term is derived from 2 Greek words: ésò, meaning inward, and trépò, meaning turn. In esotropia, the eyes are crossed; that is, while one eye looks straight ahead, the other eye is turned in toward the nose. This inward deviation of the eyes can begin as early as infancy, later in childhood, or even into adulthood.

Acquired esotropia can occur after infancy and is not always responsive to farsighted glasses; because of this, it does not fall into the categories of congenital esotropia or accommodative esotropia, which are described in other articles.

Although acquired esotropia can occur in patients aged 1-8 years, it typically develops in patients aged 2-5 years and appears to be infrequently associated with an underlying disease. With acquired esotropia, the angle of deviation is relatively small, and early surgical correction (when indicated) is more likely to achieve bifoveal fixation for these patients than for those with congenital esotropia.

Pathophysiology

Additional laboratory and clinical research often is required to determine the etiology of the acquired strabismus. Scientists agree that some strabismus cases arise from a primary motor anomaly, while others arise from a primary sensory anomaly. Although different treatment approaches clearly are needed for different conditions, no agreement exists on the details for many conditions.

Frequency

International

Of those children with esotropia, 10.4% of them are diagnosed with acquired esotropia.

Mortality/Morbidity

Organic pathologies have been diagnosed in patients initially presenting with strabismus. In a recent study, 11.52% of patients with strabismus had posterior segment abnormalities. The most common diagnoses included Toxoplasma chorioretinitis, morning glory anomaly, Toxocara retinopathy, retinopathy of prematurity, and Coats disease. The mean age of onset of the deviation was found to be significantly lower in patients with esotropia. No correlation existed between the degree of visual impairment and the direction of deviation. This fact emphasizes the importance of performing a fundus examination in each patient presenting with strabismus.

Race

No racial predilection exists.

Sex

No sexual predilection exists.

Age

The median age of onset for children with acquired esotropia is 31.4 months (range, 8-63 mo), with a mean initial angle of deviation of 24 prism diopters (PD).

CLINICAL

Section 3 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

History

The family of the patient may notice an inward deviation of one eye relative to the other eye. In assessing the patient, also evaluate the following:

• Establish family history of strabismus or related diseases.
• Note age of onset of strabismus. Photographs of patients at different ages often can help to determine if the esotropia was present prior to age 6 months and only recently appreciated by the patient's family versus truly acquired (after age 6 mo).

Physical

• Carefully examine visual acuity in a manner appropriate for the patient's age.
• • For patients too young to subjectively quantify their visual acuity levels, objective methods are used.
  • For patients aged 1-3 years, subjective methods, such as Allen cards, often 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.
• Determine stereoacuity using polarized glasses and Randot stereogram.
• Check extraocular movements to ensure that the eye movements are full.
• Measure or estimate the angle of deviation.
• • The easiest method is to evaluate the centration of the corneal light reflex in each eye, while the patient fixes on objects at distance or near.
  • In some cases, performing the alternate cover test is possible. Ask 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, as an eye is uncovered, it turns out to fixate. In accommodative esotropia, the angle of deviation is often the same when measured at distance and near fixation (usually 20-40 PD), but it can vary depending on the accommodative convergence/accommodation (AC/A) ratio.
• Measure the AC/A ratio.
• • If the AC/A ratio is high, then the deviation measured at near will be significantly greater than that at distance.
  • In true accommodative esotropia, the AC/A ratio should be normal (approximately 4/1-6/1); distance and near measurements should be the same.
• Perform a 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 optic nerve.
• Perform cycloplegic refraction on all children by using the retinoscope and trial lenses. Cycloplegia often can be 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.

Causes

Decompensation of a preexisting phoria or monofixation syndrome appears to be the most common etiology of acquired esotropia. Other possible etiologies include the following:

• Children who have been farsighted and have not worn glasses
• Children who were initially responsive to glasses but later developed additional eye crossing (nonaccommodative esotropia) even with full hyperopic correction
• Heredity
• Abnormalities in pregnancy and delivery
• Arnold-Chiari malformation
• Scleral ectasia in high myopia that can lead to a "downslip" of the lateral rectus muscle relative to the globe, giving this muscle a depressing effect at the cost of its physiological action
• Myopic epikeratophakia
• Neurologic abnormalities
• Deficits of abduction
• • Sixth nerve palsy
  • Sixth nerve pseudo-palsy in children with esotropia with manifest-latent nystagmus
  • Unilateral or bilateral type 1 Duane syndrome
• Heroin detoxification: Eye misalignments can occur during heroin use and heroin detoxification and can cause persisting diplopia (double vision) (Firth, 2005).
• Occult sinus disease: Sinusitis supposedly leads to inflammation and secondary contracture in adjacent extraocular muscles (Ludwig, 2004).

DIFFERENTIALS

Section 4 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

WORKUP

Section 5 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Imaging Studies

• Consider neuroimaging studies in the absence of expected findings (eg, hypermetropia) or fusion potential or in the presence of atypical features or neurologic signs.
• CT scan of orbits - Axial and coronal views, 3-mm cuts
• • Evaluation of fractures
  • Assessment of potential extraocular muscle entrapment
  • Presence of orbital mass
• Chest x-ray
• • Lung nodules suggestive of lung carcinoma
  • May identify suspicious breast lesion
• CT scan of neck/thorax/abdomen - To evaluate for systemic malignancy
• B-scan ultrasonography - If any doubt of globe integrity
• Radiographic imaging studies (eg, MRI of brain and brainstem) if neurologic signs or craniofacial anomalies are present

Other Tests

• Bagolini striated glasses test
• • Most tests for fusion, suppression, and Anomalous Retinal Correspondence (ARC) create artificial viewing circumstances. Normally, the visual environment is not that of a red filter in front of one eye or a combination of red-green filters; separately viewed slides in illuminated tubes are nothing more than a laboratory analysis of retinal correspondence.
  • The striated glasses popularized by Bagolini allow the patient to view the normal visual environment with a faint reference line placed on the background viewed by each eye. The reference line for each eye is placed at right angles by arranging the glasses in the trial frame so that the striations before the right eye and the left eye are perpendicular to each other. For example, the striations are placed at 135° in the trial frame in front of the right eye and at 45° in front of the left eye. The patient views a fixation light at any distance chosen by the examiner; ordinary room illumination is maintained. The patient reports on the fixation light and observed streaks extending out into the peripheral field of vision.
  • Patients with esotropia of 10 D or more give varied responses, depending on whether they have Normal Retinal Correspondence (NRC), ARC monocular vision, or an absence of binocular vision.
  • • The esotropic patient with NRC sees 2 fixation lights in homonymous diplopia, with a separate streak through each lens and without a break in either streak. Compensating for the esotropic angle with base-out prisms eliminates the diplopic fixation light, and the streaks then intersect at the fixation light.
    • The patient with ARC and suppression sees 1 fixation light and 2 streaks forming an X; after being questioned, the patient recognizes the suppression scotoma projecting from the nasal retina of the deviated eye as a gap of 5-6° around the fixation light in the streak seen by that eye.
    • The scotoma can be studied further by removing the striated glass from in front of the fixating eye and slowly rotating the striated glass before the nonfixating eye. As the streak rotates, the gap in the streak around the fixation light persists, beautifully outlining the scotoma for 360°. Furthermore, ARC is made evident by the patient's claim that the streak seen by the deviated eye passes through the fixation light as the patient mentally connects the 2 ends of the gap in this streak. When the light is held in front of the eyes, base-out prism power equal to the esotropic deviation produces crossed diplopia for the fixation light, and each light has its separate streak passing through it.
    • The patient devoid of single binocular vision sees only 1 light and 1 streak. The patient may claim to see 2 streaks if rapidly alternating but will admit under questioning that the 2 streaks are not perceived simultaneously.
  • The patient with exotropia of 10 D or more may report NRC with heteronymous diplopia, ARC with suppression, or an absence of binocular vision.
  • • The large profound scotoma of the temporal retina, extending up to the hemiretinal line in the exotropic patient with ARC, prevents all but the best observers from appreciating the extremely peripheral small streak seen outside the suppression scotoma of the deviated eye. Consequently, many exotropic patients report seeing only 1 streak.
    • Those patients who can detect the small peripheral ends of the streak describe the ends on the axis that coincides with the light, supporting the diagnosis of ARC. Furthermore, base-in prism power placed in front of the eyes that equals the deviation angle creates homonymous diplopia of the fixation light, each image having a separate streak.
  • The Bagolini striated glasses test requires a degree of maturity that seldom is found in a child younger than 8 years. Describing or drawing the suppression scotoma gap in 1 of the streaks presents great difficulty to the young child.

TREATMENT

Section 6 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical Care

• The treatment of the patient with strabismus is based on the underlying cause. In the absence of organic pathology, the treatment plan is formulated based on the interpretation and analysis of the motility examination results and the overall ocular evaluation. Besides the establishment and stabilization of single binocular vision, the significance of normal ocular alignment for the development of a positive self-image and interpersonal eye contact cannot be overemphasized. The goals of treatment may include the following:
• • Obtaining optimal visual acuity in each eye
  • Obtaining and/or improving fusion
  • Obtaining a favorable functional appearance of the alignment of the eyes
• Indications for and specific types of treatment need to be individualized for each patient. The treatment of the patient with strabismus may include any or all of the following:
• • Optical correction
  • Added lens power
  • Prisms to eliminate diplopia and to reestablish binocular vision
  • Active orthoptics/vision therapy
  • Amblyopia treatment
  • Pharmacologic agents
  • Extraocular muscle surgery in stable deviations too large to allow spontaneous binocular fusion
  • Chemodenervation

Surgical Care

Prescribing the full hypermetropic correction determined by cycloplegic refraction forms an essential part of initial management. Undercorrection of hyperopia remains a common cause of acquired esotropia. Prism adaptation may be of some value in reducing the frequency of surgical undercorrection in nonaccommodative cases; however, published data, including the results of the Prism Adaptation Study, indicate persistent undercorrection rates of nearly 20%. Other approaches, including modifying dosage tables, operating for the near angle, and augmenting surgery based on the accommodative component, have been proposed and supported by data from a number of small clinical series. A review of recent experience shows that augmentation of surgery using a combination of these approaches can provide excellent results.

• In patients with acquired esotropia, surgery is indicated when the deviation is greater than 15 PD and stable. If lateral rectus muscle weakness, incomitance, papilledema, or systemic neurologic deficit is evident, neuroimaging studies of the orbits and brain should be performed. Hyperopia greater than +1.50 D or any significant astigmatic refractive error should be treated with glasses prior to performing surgery. Because binocular vision commonly develops before esotropia, surgery is recommended to reestablish binocularity as soon as the pathological underlying causes are eliminated.
• Pediatric strabismus surgery is performed under general anesthesia. The presence of any medical condition that precludes anesthetic administration or any life-threatening cause of esotropia (eg, brain tumor) should delay surgery.
• Bilateral medial rectus recession is performed most commonly for correction of nonaccommodative esotropia. Initial surgery is designed to correct the entire deviation. Monocular medial rectus recession and lateral rectus resection or unilateral medial rectus recession alone also have been used successfully in this situation.
• Expected surgical results
• • Clark and colleagues reported good surgical results with bilateral medial rectus recession in 5 of 6 patients with acquired esotropia. Follow-up ranged from 3 months to 3 years. All 5 patients were orthophoric, and 4 of 5 patients had 40 seconds of stereopsis. The sixth patient had a recurrent esotropia of 25 D.
  • Kittleman and Mazow achieved a functional cure (defined as alignment of the visual axes within 10 PD of orthophoria) in 66% of patients. They achieved a cosmetic cure (defined as alignment of the visual axes within 18 PD of orthophoria) in an additional 17% of patients. Seven patients required reoperation for a horizontal deviation. Some form of fusion was obtained in 85% of these patients, and 52% of patients obtained some degree of stereopsis.
• According to a recently published study by Clark and colleagues, medial rectus pulley posterior fixation, a technique of suturing the pulley to its muscle without scleral sutures, may be as effective as traditional scleral posterior fixation in primary treatment of acquired esotropia with a high AC/A ratio.
• Unilateral or bilateral lateral rectus resection is commonly performed for the correction of an eventual residual esotropia after bilateral medial rectus recession. Performing bilateral lateral rectus resection in patients with residual esotropia after bilateral medial rectus recession is considered appropriate because of the high success rate and the provision of a stable alignment during a long-term follow-up period (Jang, 2004).

Consultations

Consult a neurologist/neurosurgeon if neurologic abnormalities (eg, tumor, hydrocephalus) are suspected based on clinical and radiologic findings.

Diet

Dietary treatment is not useful in treating patients with any form of strabismus.

Activity

Physical activity is not useful in treating patients with any form of strabismus. Orthoptics/vision therapy can be very effective in treating patients with some forms of strabismus.

MEDICATION

Section 7 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Drugs are used only to diagnose the disease.

Drug Category: Cycloplegics/Mydriatics

For the diagnosis of acquired esotropia.

FOLLOW-UP

Section 8 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Further Outpatient Care

• Regular follow-up care is indicated to monitor the patient's eye alignment.
• Relief from the eventual diplopia may be achieved through prismatic correction, and the deviation may then resolve spontaneously. Botulinum toxin or surgical intervention may be necessary in cases that do not resolve.

Complications

• The most common complication associated with surgery for acquired esotropia is unsatisfactory alignment. Surgery usually is performed on the unoperated horizontal muscles in an effort to reestablish binocular function.

Prognosis

• Binocular sensory function is usually severely compromised by even brief periods of abnormal binocular experience during the first year of life.

Patient Education

• The prognosis, as well as advantages and disadvantages of the various modes of treatment, should be discussed with the patient's parents and/or the patient, and a plan should be developed based on this dialogue.

MISCELLANEOUS

Section 9 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical/Legal Pitfalls

• Prompt detection and treatment are necessary to prevent development of amblyopia and/or loss of binocular vision.
• Awareness of the mechanism esotropia may avoid referrals to other specialties (eg, neurology).
• Awareness of the treatment modalities may encourage patients to seek appropriate help for relief of their symptoms.

Special Concerns

• In parallel with more detailed studies of clinical populations, continued experimental work is needed to characterize the developmental plasticity of the specific neural mechanisms involved in strabismus. These include mechanisms of stereoscopic vision and visual sensitivity to pattern and form and the role of ocular proprioception.
• An important goal in the ensuing years is to study the mechanisms of binocular vision in individuals with and without esotropia. Binocular vision is both easy to disrupt and difficult to restore after a period of anomalous visual experience, but the neural basis for these properties is unknown.
• Researchers need to improve upon the methods of detecting strabismus in infants and young children, and, once detected, they must continue to learn how to effectively treat these abnormalities to ensure optimal visual development. Discovering new diagnostic and surgical techniques for the evaluation and treatment of patients with strabismus is important and deserving of continued study.
• Photographic, video-based, and optoelectronic techniques are being developed for semiautomatic or automatic detection of refractive errors, strabismus, and amblyopia in infants and young children. These methods must be developed further to be cost-effective for mass screening.
• Automated eye tracker–based measurement of strabismus in not limited children in different directions of gaze is a worthy goal for technology development.

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

• Clark AC, Nelson LB, Simon JW. Acute acquired comitant esotropia. Br J Ophthalmol. Aug 1989;73(8):636-8. [Medline].
• Clark RA, Ariyasu R, Demer JL. Medial rectus pulley posterior fixation: a novel technique to augment recession. J AAPOS. Oct 2004;8(5):451-6. [Medline].
• Costello PA, Simon JW, Jia Y, Lininger LL. Acquired esotropia: subjective and objective outcomes. J AAPOS. Jun 2001;5(3):193-7. [Medline].
• Firth AY. Heroin and diplopia. Addiction. Jan 2005;100(1):46-50. [Medline].
• Fukai S, Arai N, Hayakawa T, Kimura H. Studies on the botulinum therapy for esotropia improvement of retinal correspondence. Nippon Ganka Gakkai Zasshi. Jun 1993;97(6):757-62. [Medline].
• Goldman HD, Nelson LB. Acute acquired comitant esotropia. Ann Ophthalmol. Dec 1985;17(12):777-8. [Medline].
• Jang GJ, Park MR, Park SC. Bilateral lateral rectus resection in patients with residual esotropia. Korean J Ophthalmol. Dec 2004;18(2):161-7. [Medline].
• Kittleman WT, Mazow ML. Reoperations in esotropia surgery. Ann Ophthalmol. May 1986;18(5):174-7. [Medline].
• Ludwig IH, Smith JF. Presumed sinus-related strabismus. Trans Am Ophthalmol Soc. 2004;102:159-65; discussion 165-7. [Medline].
• Lyons CJ, Tiffin PA, Oystreck D. Acute acquired comitant esotropia: a prospective study. Eye. Oct 1999;13 (Pt 5):617-20. [Medline].
• Mohney BG. Common forms of childhood esotropia. Ophthalmology. Apr 2001;108(4):805-9. [Medline].
• Mohney BG. Acquired nonaccommodative esotropia in childhood. J AAPOS. Apr 2001;5(2):85-9. [Medline].
• Repka MX, Wentworth D. Predictors of prism response during prism adaptation. Prism Adaptation Study Research Group. J Pediatr Ophthalmol Strabismus. Jul-Aug 1991;28(4):202-5. [Medline].
• Thomas AH. Divergence insufficiency. J AAPOS. Dec 2000;4(6):359-61. [Medline].
• Troost BT, Abel L, Noreika J, Genovese FM. Acquired cyclic esotropia in an adult. Am J Ophthalmol. Jan 1981;91(1):8-13. [Medline].

Article Last Updated: Oct 16, 2006