Esotropia, often referred to as “crossed eyes,” is a condition where one or both eyes turn inward toward the nose. This misalignment can be constant or intermittent, affecting not just physical appearance but also the ability to see clearly. For children, untreated esotropia can lead to amblyopia (lazy eye) and permanent vision loss, while adults may experience disorienting double vision and eye strain. Beyond the visual challenges, the condition can impact self-esteem and social confidence.

Treatment is essential to align the eyes, restore binocular vision, and protect depth perception. The approach to care is highly individualized; what works for an infant with congenital esotropia may differ significantly from the needs of an adult with sudden-onset symptoms. While corrective lenses and surgery are common interventions, medications play a specific and valuable role in managing certain types of the condition and its associated complications (American Association for Pediatric Ophthalmology and Strabismus, 2023).

Overview of treatment options for Esotropia

The primary goals of treating esotropia are to straighten the eyes and ensure the brain uses both eyes together. Treatment plans are tailored based on the cause, such as whether the turning is linked to farsightedness (accommodative esotropia) or muscle imbalance.

While glasses are often the first line of defense for accommodative types, and surgery is used for structural muscle issues, pharmaceutical options serve as critical adjunctive therapies. Medications are typically used to manipulate the eye muscles or the focusing mechanism of the eye. They are particularly useful in cases where surgery is not immediately viable, for diagnostic purposes, or to treat the “lazy eye” that frequently accompanies the turning.

Medications used for Esotropia

In the management of esotropia, medications are primarily administered locally as eye drops or injections rather than oral pills.

One of the most notable pharmacological treatments is the use of botulinum toxin type A. This biologic agent is injected directly into the eye muscle responsible for pulling the eye inward (the medial rectus). It is often used as an alternative to traditional surgery for infants or for adults with acute onset esotropia. Clinical experience suggests that for some patients, a single injection can permanently correct the alignment or significantly reduce the angle of the turn.

Another class of medications involves miotics, specifically cholinesterase inhibitors like echothiophate iodide. These potent eye drops are rarely used today but remain a second-line option for accommodative esotropia when glasses alone are insufficient or not tolerated. They help reduce the eye’s need to over-focus, which triggers the crossing.

Additionally, cycloplegic agents such as atropine are frequently used. While atropine does not straighten the eye directly, it is a cornerstone of “penalization therapy” for amblyopia associated with esotropia. By blurring the vision in the straight (dominant) eye, it forces the brain to use the crossed (weaker) eye, strengthening its visual connection (American Academy of Ophthalmology, 2022).

How these medications work

Botulinum toxin temporarily blocks acetylcholine, weakening the inner eye muscle. This allows the opposing outer muscle to pull the eye toward the center, often leading to lasting alignment.

Miotics stimulate the ciliary muscle, reducing the effort needed for focusing (accommodation). Since eye crossing is linked to focusing effort, reducing this effort keeps the eyes straighter.

Atropine temporarily paralyzes the stronger eye’s focusing muscle and dilates its pupil, forcing the brain to rely on the misaligned eye to improve its vision (National Eye Institute, 2023).

Side effects and safety considerations

Eye medications carry specific risks. Botulinum toxin injections may cause temporary eyelid drooping (ptosis) or double vision, which resolves as the drug wears off, reflecting the temporary muscle weakness it induces.

Miotics such as echothiophate can lead to headaches, brow aches, or iris cysts. Atropine drops often cause light sensitivity and blurred near vision in the treated eye. Since systemic absorption of eye drops can occur, parents are often instructed to block the tear duct during application to minimize side effects like dry mouth or flushing. Patients should seek medical attention for severe eye pain or breathing changes.

Since everyone’s experience with the condition and its treatments can vary, working closely with a qualified healthcare provider helps ensure safe and effective care.

References

1. American Academy of Ophthalmology. https://www.aao.org
2. American Association for Pediatric Ophthalmology and Strabismus. https://www.aapos.org
3. National Eye Institute. https://www.nei.nih.gov
4. Mayo Clinic. https://www.mayoclinic.org