Clinical UM Guideline

This document addresses strabismus, which refers to eyes that are not properly aligned. Examples of strabismus include one or both eyes that are intermittently or constantly turned in towards the nose (esotropia) or out (exotropia). Strabismus surgery involves surgical weakening or strengthening of the ocular muscles to correct the ocular alignment. The goals of strabismus surgery are to restore or reconstruct normal ocular alignment, obtain normal visual acuity in each eye, obtain or improve fusion, eliminate any associated sensory adaptations or diplopia, and to improve visual fields.

Note: The use of botulinum toxin is not addressed in this document. For related information, please refer to the guidelines used by the plan.

Medically Necessary:

Adults
Surgical strabismus correction for individuals 18 years of age or older is considered medically necessary for any of the following:

1. Diplopia; or
2. Visual confusion; or
3. Restoration of binocular vision; or
4. Intolerance of prism glasses or patch; or
5. Restoration of visual field in individuals with esotropia; or
6. Elimination or improvement of abnormal head posture; or
7. Improvement of psychosocial function or vocational status.

Pediatrics
Surgical strabismus correction in individuals less than 18 years of age is considered medically necessary for any of the following:

1. Infantile esotropia (inward deviation) with onset before 6 months of age; or
2. Acquired non-accommodative esotropia; or
3. Partially accommodative esotropia; or
4. Any deviation due to neural dysfunction, or threatening normal binocular vision; or
5. Intermittent exotropia (outward deviation); or
6. Constant exotropia; or
7. Hyper/hypotropia (vertical deviation); or
8. Accommodative esotropia that does NOT improve with 3-6 months of refractive correction, patching or when it threatens normal binocular vision.

Not Medically Necessary:

Surgical strabismus correction is considered not medically necessary when the criteria listed above are not met and for all other indications.

The following codes for treatments and procedures applicable to this guideline are included below for informational purposes. Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy. Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

When services may be Medically Necessary when criteria are met:

When services are Not Medically Necessary:
For the procedure codes listed above when criteria are not met or for situations designated in the Clinical Indications section as not medically necessary.

Summary

The primary goals of strabismus surgery are functional, aiming to restore ocular alignment, improve or establish binocular vision, and alleviate debilitating symptoms such as diplopia. In adults, this principle is supported by long-standing professional guidelines and reinforced by recent evidence showing substantial success in resolving diplopia and improving quality of life, including in very elderly populations where safety and efficacy are critical. In children, the emphasis is on the timely development of normal binocular vision and prevention of long-term sensory deficits. Multiple studies support early surgical alignment to maximize the potential for fusion, with high success rates demonstrated in common conditions such as intermittent exotropia. Importantly, large-scale registry data indicate that in cases of strabismic amblyopia, surgery does not provide additional visual acuity benefit beyond standard amblyopia therapy, reinforcing that pediatric surgical indications are appropriately directed at restoring alignment and binocular function rather than acuity gains.

Discussion

Adults

In 2017, the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) and the American Academy of Ophthalmology (AAO) updated the Adult Strabismus Surgery joint policy statement Adult Strabismus Surgery. The indications for surgical intervention for adults with strabismus to restore and reconstruct normal ocular alignment include:

Strabismus is abnormal binocular alignment; adult strabismus surgery aims to restore or reconstruct normal ocular alignment. Indications for surgical intervention include:

• Diplopia: perception of the same image in two different visual directions that impairs reading, driving, and work. Visual confusion: perception of two different images superposed in the same space, often hazardous when driving.
• Restoration of binocular vision: misalignment causes loss of fusion and depth perception; many adults regain fusion after realignment.
• Intolerance of prism glasses or patch: prisms relieve symptoms only while worn, are optically distorting for large deviations, and are usually ineffective in incomitant strabismus; patching abolishes binocular function and is a temporizing measure.
• Restoration of visual field in esotropia: surgical realignment expands the binocular field regardless of amblyopia and supports safe peripheral vision.
• Elimination or improvement of abnormal head posture: compensatory face turn or head tilt used to reduce diplopia can improve after surgery, including associated neck contractures.
• Psychosocial function and vocational status: strabismus negatively affects employment, promotions, interpersonal communication, and mental health; these outcomes improve after surgery.

Common etiologies in adults include diabetes, thyroid or Graves disease, myasthenia gravis, brain tumor, head trauma, and stroke. Adults with a history of childhood strabismus may develop diplopia after visual maturation if the direction or magnitude of deviation changes. Surgical realignment can relieve diplopia and visual confusion, restore fusion and depth perception, expand the visual field in esotropia, reduce abnormal head posture, and improve psychosocial and mental health outcomes (AAPOS/AAO, 2017).

Liebermann and colleagues (2014) reported improvement in health-related quality of life (HRQOL) using the Adult Strabismus 20 (AS-20) questionnaire. This retrospective review focused on non-diplopic adults that had childhood onset strabismus and had corrective surgery with pre- and post-AS-20 results available. Statistically significant improvement (p<0.05) in 9 out of 10 function-related questions were noted. The authors noted these results suggest function-related benefits for adults who had surgical strabismus surgery. However, the limitations of the study include the small number of participants (n=20) who met inclusion criteria, and the retrospective approach. The authors noted ongoing study of HRQOL in adults with surgical correction for strabismus is needed to verify their results.

The AAO states in the preferred practice pattern guideline Adult Strabismus (Dagi, 2024) that the goal of adult strabismus surgery is to optimize an individual’s functional visual status while also addressing psychosocial concerns. The potential benefits of adult strabismus surgery include the following:

• Improvement in binocularity (ranging from simultaneous perception to stereopsis).
• Reduction of diplopia or compensatory head position.
• Improvement of binocular visual field.
• Improvement in binocular summation or resolution of binocular inhibition.
• Reduction of asthenopia.
• Psychosocial benefits related to restoration of more normal ocular alignment.
• Reconstruction of an abnormal facial appearance secondary to ocular misalignment.
• Acknowledge the desire of many patients to be free from prism glasses.

Regarding strabismus surgery in adults, the AAO (Dagi, 2024) notes that:

Success rates depend on the subpopulation studied and the goals of surgery, but overall they are approximately 80% after one procedure and may exceed 95% if a second procedure is performed on eyes failing the first intervention. . . . Patients should be informed that surgical success rates vary widely depending on the type of strabismus, number of dysfunctional muscles, previous ocular and strabismus surgery, orbital or hardware involvement, and associated systemic and neurological conditions.

Finally, Yehezkeli (2025) reported the results of a 10‑year cohort of 165 patients aged 80 to 94 years. They reported that diplopia was the presenting indication in 94% and was resolved in 75% of study participants after the first procedure and in 87% after up to two additional procedures. With a 13% reoperation rate, no intraoperative anesthesia or surgical complications were noted. Additionally, marked reductions in prism dependence and measurable gains in stereopsis were reported. Most cases were performed with topical or local anesthesia and the mean American Society of Anesthesiologists class was 2.6. They concluded that octogenarians derive substantial functional benefit from surgery with acceptable surgical risk.

Pediatrics

The development of binocularity is the goal in children, especially the very young. Evidence suggests that early alignment of the eyes in young children may improve the prognosis for binocular vision. The American Optometric Association (AOA, 2012) reported for children with infantile esotropia, “Achieving binocular alignment early in life (before age 2 years) to within 10 prism diopters of orthotropia increases the likelihood of achieving binocularity.” The AAO (2012) notes acquired esotropia occurs more frequently than infantile esotropia, and those with “Early onset acquired esotropia are more likely to require extraocular muscle surgery despite correction of their refractive error with eyeglasses.” Prompt surgical realignment in individuals with decompensated accommodative esotropia appears to improve the quality of stereopsis. Early surgery is indicated for those with constant infantile-onset exotropia to improve sensory outcomes. Likewise, the AAO notes in the preferred practice pattern guideline Esotropia and Exotropia (2022) that “There is evidence that early surgical correction improves sensory outcomes for infantile esotropia, probably because the duration of constant esotropia is minimized.”

An updated Cochrane systematic review (Mehner, 2023) identified two randomized trials. One trial found surgery may yield higher short-term alignment success than botulinum toxin for large-angle infantile esotropia, but the certainty of evidence was very low and minor complications were more frequent with botulinum toxin. A second trial found no important difference between unilateral and bilateral surgery. High-quality randomized data on optimal timing remain lacking; observational data suggest earlier alignment may improve gross stereopsis but at the cost of higher reoperation rates. Decisions on timing should consider the individual's ocular and neurologic status, as well as family preferences.

The AOA notes in the preferred practice pattern guideline Esotropia and Exotropia (2012) there are multiple factors involved in the timing and urgency for surgical referral, including but not limited to the type of strabismus; age of the child; and the likelihood of improving fusion. Children with infantile strabismus requiring surgical correction should ideally undergo surgery prior to 2 years of age. Development of binocularity with limited stereopsis have been demonstrated in studies when surgery is performed at an early age and when the duration of ocular misalignment has not been extensive.

There are multiple modalities utilized to address esotropia and exotropia, which may include (AAO, 2012):

• Correction of refractive errors;
• Bifocals;
• Prism therapy;
• Amblyopia treatment;
• Extraocular muscle surgery (strabismus surgery);
• Botulinum toxin A injection;
• Convergence exercises for convergence insufficiency exotropia;
• Stimulating accommodative convergence (overcorrection of myopia or undercorrection of hyperopia);
• Other methods.

Eleven studies satisfied the eligibility criteria of a systematic review of the treatment of childhood intermittent exotropia. Seven studies compared unilateral to bilateral resection. Four studies compared surgical to non-surgical interventions. While surgical interventions appeared to be more effective than non-surgical interventions in improving the angle of deviation, the authors note that the studies were of limited extent and quality with heterogeneous outcomes assessments and timeframes (Joyce, 2015).

Management strategies for intermittent exotropia include both surgical and non-surgical approaches. A 2021 Cochrane systematic review analyzing six randomized controlled trials (N=890) provided updated evidence on these interventions (Pang, 2021). High-certainty evidence demonstrated that part-time patching is superior to active observation for improving motor alignment at six months in children aged 12 months to 10 years. Regarding surgical techniques, moderate-certainty evidence from a large RCT indicated little difference in motor alignment outcomes at three years when comparing bilateral lateral rectus recession with unilateral recession-resection for basic-type intermittent exotropia. In a study by Lino (2025), bilateral lateral rectus recession for intermittent exotropia produced a 92.2% success rate at six months when success required residual deviation of 10 prism diopters or less plus stereopsis of 80 arcseconds or better; smaller preoperative deviation angle strongly predicted success, while sex, age, subtype, and preoperative occlusion were not independent predictors after adjustment, underscoring preoperative angle as the key planning variable

Hoehn (2025) reported that in children with strabismic amblyopia, registry data show that visual acuity improves over time with amblyopia treatment irrespective of whether strabismus surgery is performed before or within six months of diagnosis; surgery conferred no additional acuity benefit at 6, 12, or 24 months across age strata, and did not hinder treatment efficacy, which supports policy language that pediatric surgical indications target alignment, fusion, and functional binocular outcomes rather than acuity gains.

Amblyopia: Vision in one of the eyes is reduced because the eye and the brain are not working together properly. The eye itself looks normal, but it is not being used normally because the brain is favoring the other eye. This condition is also sometimes called lazy eye.

Asthenopia: Eye strain or fatigue.

Binocular: Referring to the use of both eyes.

Diplopia: Double vision.

Hypertropia: A classification of strabismus with the eye turning in an upward direction.

Hypotropia: A classification of strabismus with the eye turning in a downward direction.

Orthotropia: The absence of strabismus.

Prism diopter: The customary unit of measurement of the magnitude of deviation of the visual axes in strabismus. One prism diopter is the angle subtended by a deviation of 1 centimeter at a distance of 1 meter.

Peer Reviewed Publications:

1. Alam D, Khan AA, Bani SA, et al. Gain beyond cosmesis: demonstration of psychosocial and functional gains following successful strabismus surgery using the adult strabismus questionnaire adult strabismus 20. Indian J Ophthalmol. 2014; 62(7):799-803.
2. Beauchamp GR, Black BC, Coats DK, et al. The management of strabismus in adults--II. Patient and provider perspectives on the severity of adult strabismus and on outcome contributors. J AAPOS. 2005; 9(2):141-147.
3. Beauchamp GR, Felius J, Stager DR, Beauchamp CL. The utility of strabismus in adults. Trans Am Ophthalmol Soc. 2005; 103:164-171; discussion 171-172.
4. Bradbury JA, Taylor RH. Severe complications of strabismus surgery. J AAPOS. 2013; 17(1):59-63.
5. Gusek-Schneider G, Boss A. Results following eye muscle surgery for secondary sensory strabismus. Strabismus. 2010; 18(1):24-31.
6. Hoehn ME, Nabavi A, Rahdar A, Delsoz M, Lum F, Yousefi S. Visual outcomes after strabismus surgery in pediatric patients with strabismic amblyopia: an IRIS registry study. Ophthalmology. 2025; 132(9):1005-1012.
7. Joyce KE, Beyer F, Thomson RG, Clarke MP. A systematic review of the effectiveness of treatments in altering the natural history of intermittent exotropia. Br J Ophthalmol. 2015; 99(4):440-450.
8. Kushner BJ. The benefits, risks, and efficacy of strabismus surgery in adults. Optom Vis Sci. 2014; 91(5):e102-109.
9. Liebermann L, Hatt SR, Leske DA, Holmes JM. Improvement in specific function-related quality-of-life concerns after strabismus surgery in nondiplopic adults. J AAPOS. 2014; 18(2):105-119.
10. Lino P, de Aguiar PV, Cunha JP. Success of strabismus surgery in intermittent exotropia. J Pers Med. 2025; 15(8):333.
11. McBain HB, Au CK, Hancox J, et al. The impact of strabismus on quality of life in adults with and without diplopia: a systematic review. Surv Ophthalmol. 2014; 59(2):185-191.
12. Mets MB, Beauchamp C, Haldi BA. Binocularity following surgical correction of strabismus in adults. J AAPOS. 2004; 8(5):435-438.
13. Mills MD, Coats DK, Donahue SP, et al. Strabismus surgery for adults: a report by the American Academy of Ophthalmology. Ophthalmology. 2004; 111(6):1255-1262.
14. Pineles SL, Demer JL, Isenberg SJ, Birch EE, Velez FG. Improvement in binocular summation after strabismus surgery. JAMA Ophthalmol. 2015; 133(3):326-332.
15. Ribeiro Gde B, Bach AG, Faria CM, et al. Quality of life of patients with strabismus. Arq Bras Oftalmol. 2014; 77(2):110-113.
16. Yehezkeli V, Pineles SL, Demer JL, et al. Strabismus surgery in patients aged over 80 years: indications, safety, and outcomes. Am J Ophthalmol. 2025; 272:145-149.

Government Agency, Medical Society, and Other Authoritative Publications:

1. American Academy of Ophthalmology Pediatric Ophthalmology/Strabismus Panel. Preferred Practice Pattern^® Guidelines. Amblyopia. San Francisco, CA: American Academy of Ophthalmology; 2022. For additional information visit the AAO website: https://www.aao.org/education/preferred-practice-pattern/amblyopia-ppp-2022. Accessed on September 20, 2025.
2. American Association for Pediatric Ophthalmology and Strabismus and the American Academy of Ophthalmology. Adult strabismus surgery joint policy statement. 2017. For additional information visit the AAO website: https://www.aao.org/education/clinical-statement/adult-strabismus-surgery. Accessed on September 20, 2025.
3. American Academy of Ophthalmology Pediatric Ophthalmology/Strabismus Panel. Preferred Practice Pattern^® Guidelines. Esotropia and exotropia. San Francisco, CA: American Academy of Ophthalmology; updated 2022. For additional information visit the AAO website: https://www.aao.org/education/preferred-practice-pattern/esotropia-exotropia-ppp. Accessed on September 20, 2025.
4. American Optometric Association. Optometric clinical practice guideline. Care of the patient with strabismus: esotropia and exotropia. Revised 2010. Available at: https://www.aoa.org/AOA/Documents/Practice%20Management/Clinical%20Guidelines/Consensus-based%20guidelines/Care%20of%20Patient%20with%20Strabismus%20Esotropia%20and%20Exotropia.pdf. Accessed on September 20, 2025.
5. Centers for Disease Control and Prevention. Vision and Eye Health. Available at: https://www.cdc.gov/vision-health/?CDC_AAref_Val=https://www.cdc.gov/visionhealth/basics/index.html. Accessed on September 20, 2025.
6. Dagi LR, Velez FG, Holmes JM, et al.; on behalf of the American Academy of Ophthalmology Preferred Practice Pattern Adult Strabismus Panel. Adult strabismus preferred practice pattern®. Ophthalmology. 2024; 131(4):306-403.
7. Korah S, Philip S, Jasper S, et al. Strabismus surgery before versus after completion of amblyopia therapy in children. Cochrane Database Syst Rev. 2014; (10):CD009272.
8. Mehner L, Ng SM, Singh J. Interventions for infantile esotropia. Cochrane Database Syst Rev. 2023;1(1):CD004917.
9. Pang Y, Gnanaraj L, Gayleard J, et al. Interventions for intermittent exotropia. Cochrane Database Syst Rev. 2021;9(9):CD003737.

1. American Association for Pediatric Ophthalmology and Strabismus. Available at: http://www.aapos.org/. Accessed on September 20, 2025.
   • Strabismus. Updated October 7, 2020.
   • Adult Strabismus. Updated December 2022.
   • Strabismus surgery. Updated January 2022.
2. National Eye Institute (NEI). Amblyopia (Lazy Eye). Last updated November 26, 2024. Available at: https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/amblyopia-lazy-eye. Accessed on September 20, 2025.

Strabismus

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