Tanu Sharma, B. Optom

Clinical Optometrist, Vision Eye Center, New Delhi, India

 

Heavy Eye Syndrome (HES) is a cause of acquired esotropia in the setting of high myopia. HES typically presents with diplopia secondary to progressive esotropia and hypotropia with limitation of abduction and elevation and it is hypothesized that HES is the result of lateral rectus (LR) and superior rectus (SR) shifts caused by the elongated posterior portion of the eyeball due to high myopia. It is expressed as an inferior shift of LR causing reduced abduction and infra-adduction while the nasal shift of SR causes reduced supra-adduction and increased adduction. Consequently, HES shows both eso-deviation and hypo-deviation due to increased adduction and infra-adduction reduced abduction and supra-adduction. (1)

This article aims to describe the high-myopic induced strabismus as nowadays high myopic error is common and can lead to strabismus.

One article suggested that HES classically presents with progressive large-angle esotropia and hypotropia causing limited abduction and supraduction in high myopes, as patients with HES exhibit superior-temporal globe prolapse of the elongated, myopic globe that displaces the LR inferiorly while SR and IR medially. (2)

One study detected muscle displacement in all subjects and showed the alteration of the LR -SR band in patients with HES suggesting a potential role in the pathogenesis of the anatomical mal-development of the eye. The evaluation of preoperative orbital MRI Imaging in patients with highly myopic strabismus is helpful to detect different anatomical aetiologies and eventually, driving the choice of appropriate surgery. (3)

One study suggests that age-related LR and SR band degeneration permits the lateral rectus muscle slip to inferiorly in the elderly in non-myopes, a mechanism of strabismus similar to myopic “ heavy eye syndrome”. Imaging may assist in the diagnosis of this mechanical cause of age-related strabismus. (4)

A recent study showed that combined exotropia and hypotropia associated with high myopia show an overlap in the clinical presentation of the HES. (5)

Another study explained that HES may be due to abnormal rectus muscle anatomies, such as axial elongation and alteration in the direction of the lateral and superior recti, mitochondrial myopathy, and orbital connective tissue degeneration associated with aging.

Clinical Evaluation:

  • History – HES is not usually seen in childhood Patients typically have high myopia with an average of -18.00D. Some patients complain of new-onset diplopia in adulthood while older and more myopic individuals have acquired esotropia and vertical heterotropia. (6)
  • MRI – Should be obtained with attention to the paths of rectus muscles. If altered paths of muscles are noted, the surgical option will correct the deviation.

Management:

  1. Recession-Resection – It is found the recession and resection procedure is easy and effective when the abducting disorder is not while recession and resection are less successful in patients with more severe diseases. (7)
  2. Loop Myopexy – most successful outcomes have come from correcting the muscle paths of both the superior and lateral rectus muscles.
  3. Concurrent Medial rectus recession at the time of Loop Myopexy – Bansal et al. demonstrate the efficacy of loop myopexy alone. It performed medial rectus recession at the same time as loop myopexy. (1)

 

References: 

  1. https://eyewiki.aao.org/Heavy_Eye_Syndrome [Last accessed: 12Nov2022;10:00pmAEDT]
  2. Hennein L, Robbins SL. Heavy eye syndrome: Myopia-induced strabismus. Survey of Ophthalmology. 2021 Jan 1;66(1):138-44.
  3. Maiolo C, Fresina M, Campos EC. Role of magnetic resonance imaging in heavy eye syndrome. Eye. 2017 Aug;31(8):1163-7.
  4. Rutar T, Demer JL. “Heavy eye” syndrome in the absence of high myopia: a connective tissue degeneration in elderly strabismic patients. Journal of American Association for Pediatric Ophthalmology and Strabismus. 2009 Feb 1;13(1):36-44.
  5. Tan RJ, Demer JL. Heavy eye syndrome versus sagging eye syndrome in high myopia. Journal of American Association for Pediatric Ophthalmology and Strabismus. 2015 Dec 1;19(6):500-6.
  6. Padmini HR, Subhedar P. Heavy eye syndrome. Journal of Evolution of Medical and Dental Sciences. 2013 Mar 25;2(12):1905-9.
  7. Hayashi T, Iwashige H, Maruo T. Clinical features and surgery for acquired progressive esotropia associated with severe myopia. Acta Ophthalmologica Scandinavica. 1999 Feb 1;77(1):66-71.