Squint Surgery Complications: What Can Go Wrong and How to Avoid Them

Essential Insights: What Every Patient Should Know About Squint Surgery Risks

• Overall safety profile: Squint surgery has a relatively low risk profile with a 60-80% success rate for primary procedures, though success rates are 5-15% lower for revision surgeries.
• Common temporary issues: Most patients experience redness, discomfort, and possibly swelling that typically resolves within 1-2 weeks with proper care.
• Double vision concerns: Temporary diplopia is common after surgery as the brain adapts to new eye alignment, usually resolving within 6-8 weeks.
• Alignment outcomes: Under or overcorrection occurs in 5-20% of cases, with higher risks in patients with previous eye surgery, thyroid eye disease, high myopia, or advanced age.
• Vision impact: The procedure rarely affects visual acuity (less than 0.05% risk) but may temporarily change binocular vision as the brain adapts.
• Infection prevention: Post-operative infection is uncommon (approximately 0.1%) and can be minimized through proper pre-surgical preparation and aftercare.
• When results disappoint: If surgery doesn’t achieve desired results, non-surgical options or revision surgery (after 6-12 months) may be considered.

Table of Contents

• Understanding the Risks of Squint Surgery: An Overview
• Common Complications After Strabismus Surgery
• Diplopia After Surgery: Causes and Management
• Overcorrection and Undercorrection: Why They Happen
• Infection and Inflammation: Prevention and Treatment
• Can Squint Surgery Make Your Vision Worse?
• What to Do When Squint Surgery Fails
• Minimizing Risks: Pre-Surgery Preparation and Aftercare

Understanding the Risks of Squint Surgery: An Overview

Squint surgery (strabismus surgery) is a well-established procedure to correct misalignment of the eyes, but like any surgical intervention, it carries certain risks that patients should be aware of before proceeding. At London Squint Clinic, we believe in transparent communication about potential complications to help patients make informed decisions.

The overall risk profile of squint surgery is relatively low compared to many other surgical procedures. Most complications are temporary and resolve with appropriate management. The success rate for primary squint surgery typically ranges between 60-80%, with variations depending on the type and complexity of the squint.

Risks can be categorised into those related to anaesthesia, the surgical procedure itself, and post-operative complications. While general anaesthesia carries minimal risks in healthy individuals, specific surgical risks include bleeding, infection, scarring, and altered eye alignment outcomes. Post-operative complications may include persistent or new-onset double vision, under or overcorrection of the squint, and rarely, damage to surrounding structures.

It’s important to note that the likelihood of complications increases with certain factors, including previous eye surgeries, age-related changes to eye tissues, thyroid eye disease, and certain neurological conditions. Our comprehensive pre-surgical assessment helps identify individual risk factors and tailor the surgical approach accordingly.

Common Complications After Strabismus Surgery

While squint surgery is generally safe, understanding potential complications helps patients recognise and report issues promptly. The most frequently encountered complications after strabismus surgery include:

Temporary redness and discomfort: Almost all patients experience some degree of redness, irritation, and discomfort immediately after surgery. This typically resolves within 1-2 weeks and can be managed with prescribed eye drops and oral pain relief.

Conjunctival swelling (chemosis): Swelling of the clear membrane covering the white of the eye is common and usually subsides within days to weeks. Severe cases may require additional treatment with topical steroids.

Suture granuloma: Occasionally, small lumps may form at the site of dissolving stitches. These typically resolve spontaneously but may require removal if persistent or uncomfortable.

Altered tear film: Some patients experience dry eye symptoms or excessive tearing after surgery, which usually normalises within weeks but may require temporary lubricating drops.

Eyelid drooping (ptosis): Temporary drooping of the eyelid can occur due to manipulation during surgery or from the effects of local anaesthesia. This typically resolves within weeks.

Slipped or lost muscle: In rare cases (less than 1%), an operated muscle may slip from its new position or become detached. This requires prompt surgical revision.

Scleral perforation: Extremely rare but serious, this involves inadvertent penetration of the eye wall during surgery. Modern surgical techniques have significantly reduced this risk to less than 0.1% of cases.

Most complications are temporary and resolve with appropriate management. Serious complications requiring additional intervention occur in less than 2% of cases.

Diplopia After Surgery: Causes and Management

Diplopia (double vision) following squint surgery is a significant concern for many patients. While the procedure aims to eliminate double vision or improve eye alignment, temporary diplopia can occur as part of the healing process, and in some cases, may persist.

Causes of post-operative diplopia include:

• Adaptation period: The brain needs time to adjust to the new eye alignment, particularly in adults who have had long-standing squints.
• Surgical swelling: Inflammation around the operated muscles can temporarily affect their function.
• Altered muscle mechanics: Changes in the tension and position of eye muscles can initially create new patterns of misalignment.
• Unmasking of suppression: Some patients with long-standing squints develop suppression (the brain ignoring the image from one eye). Surgery may disrupt this adaptation, revealing double vision that was previously suppressed.

Management approaches include:

• Observation: Many cases resolve spontaneously within 6-8 weeks as healing progresses and the brain adapts.
• Prism glasses: Temporary or permanent prisms can be incorporated into spectacles to align the double images.
• Orthoptic exercises: Specific vision therapy exercises may help the brain adapt to the new eye position.
• Botulinum toxin: In some cases, targeted injections can help fine-tune muscle balance.
• Revision surgery: If diplopia persists beyond 6 months and significantly impacts quality of life, additional surgery may be considered.

Patients should be reassured that post-operative diplopia is often temporary. At London Squint Clinic, we carefully monitor visual symptoms during recovery and provide appropriate interventions to optimise outcomes.

Overcorrection and Undercorrection: Why They Happen

Achieving perfect alignment of the eyes after squint surgery is challenging due to the complex interplay of factors affecting eye muscle function. Both overcorrection (where the eyes move too far in the opposite direction) and undercorrection (where the original misalignment persists to some degree) can occur.

Causes of undercorrection include:

• Conservative surgical planning to avoid overcorrection
• Unexpected muscle elasticity or contracture
• Previous scarring affecting muscle function
• Mechanical restrictions not fully addressed during surgery
• Underlying neurological factors affecting eye muscle control

Causes of overcorrection include:

• Aggressive surgical adjustment
• Unexpected muscle response to surgery
• Changes in muscle function during healing
• Slippage of the muscle from its intended position
• Age-related changes in tissue elasticity

The reported rates of significant under or overcorrection requiring additional intervention range from 5-20%, depending on the complexity of the original squint. Factors increasing the risk include previous eye surgery, thyroid eye disease, high myopia (short-sightedness), and age over 65 years.

Minor degrees of under or overcorrection may not require further treatment if the patient is satisfied with the cosmetic appearance and has comfortable vision. For more significant misalignments, options include prism glasses, botulinum toxin injections, or revision surgery, typically considered after a 6-month healing period.

At London Squint Clinic, we carefully measure and document pre-operative measurements and use adjustable suture techniques in appropriate cases to optimise surgical outcomes and reduce the need for reoperation.

Infection and Inflammation: Prevention and Treatment

Infection following squint surgery is uncommon but requires prompt attention when it occurs. The reported incidence of post-operative infection is approximately 1 in 1,000 cases. Inflammation, on the other hand, is an expected part of the healing process but can sometimes become excessive.

Prevention strategies employed at London Squint Clinic include:

• Thorough pre-operative antiseptic preparation
• Sterile surgical technique and environment
• Prophylactic antibiotic eye drops
• Careful wound closure
• Detailed post-operative care instructions

Signs of infection that patients should watch for include:

• Increasing rather than decreasing pain after 48 hours
• Significant swelling with yellow or green discharge
• Spreading redness beyond the surgical site
• Decreased vision
• Fever or feeling generally unwell

Treatment of infection typically involves intensive topical antibiotics, and in severe cases, oral or intravenous antibiotics. Rarely, surgical intervention may be required to drain an abscess or remove infected sutures.

Normal post-operative inflammation presents as redness, mild swelling, and discomfort that gradually improves. This is managed with prescribed anti-inflammatory drops and cold compresses. Excessive inflammation may require more potent steroid drops or, occasionally, oral anti-inflammatory medication.

Patients are provided with 24-hour contact details following surgery to report any concerning symptoms. Early intervention for suspected infection is crucial to prevent serious complications such as endophthalmitis (infection inside the eye) or orbital cellulitis (infection of the tissues surrounding the eye).

Can Squint Surgery Make Your Vision Worse?

A common concern among patients considering squint surgery is whether the procedure might negatively impact their vision quality. It’s important to distinguish between visual acuity (the clarity of vision) and binocular vision (how the eyes work together).

Squint surgery primarily aims to improve eye alignment and binocular function rather than visual acuity itself. The surgery involves adjusting the external muscles that control eye movement and does not directly affect the internal structures responsible for visual clarity.

In terms of visual acuity, squint surgery rarely causes deterioration. The reported risk of reduced vision due to direct surgical complications is extremely low (less than 0.05%). These rare cases typically involve complications such as retinal damage from scleral perforation or vascular compromise.

However, changes in binocular vision can occur, which may temporarily affect visual comfort:

• New double vision: As discussed earlier, some patients may experience diplopia as the brain adjusts to the new eye alignment.
• Visual confusion: When the brain suddenly begins receiving aligned images from both eyes after years of suppression, temporary visual disorientation can occur.
• Depth perception changes: Patients may need time to adapt to improved stereopsis (3D vision).

In children with amblyopia (lazy eye), squint surgery alone does not improve the vision in the weaker eye. Additional treatments such as patching or atropine drops are typically required alongside surgery.

For adults with long-standing squints, the brain may have developed adaptations to maintain comfortable vision despite misalignment. Surgery disrupts these adaptations, sometimes causing temporary visual disturbances before new, healthier visual patterns develop.

At London Squint Clinic, we thoroughly assess visual function before surgery and discuss realistic expectations regarding both cosmetic and functional outcomes.

What to Do When Squint Surgery Fails

Despite careful planning and execution, squint surgery does not always achieve the desired outcome. Understanding what constitutes “failure” and the available options is crucial for patients facing this situation.

Squint surgery may be considered unsuccessful if:

• The eyes remain significantly misaligned
• Double vision persists beyond the expected adaptation period
• The squint returns after initial improvement
• New visual symptoms develop that impact quality of life

The reported reoperation rate for squint surgery varies between 15-35%, with higher rates for complex cases such as thyroid eye disease, previous multiple surgeries, or paralytic strabismus.

If you’re experiencing unsatisfactory results after squint surgery, these steps are recommended:

• Allow adequate healing time: Final results should not be judged until at least 6-8 weeks post-surgery, as alignment can continue to change during this period.
• Maintain follow-up appointments: Regular monitoring helps identify whether issues are resolving or require intervention.
• Consider non-surgical options: Prism glasses, vision therapy, or botulinum toxin injections may address residual problems without further surgery.
• Seek specialist review: Complex cases benefit from assessment by surgeons specialising in strabismus revision surgery.
• Discuss reoperation timing: If revision surgery is needed, timing is crucial—typically 6-12 months after the initial procedure to allow complete healing.

At London Squint Clinic, we specialise in complex and revision squint surgery. Our approach involves comprehensive reassessment, including detailed measurements, imaging, and when necessary, exploration of factors that may have contributed to the initial unsuccessful outcome.

Revision surgery often requires different techniques from primary surgery, including adjustable sutures, use of spacer materials, or alternative muscle procedures. Success rates for revision surgery are typically 5-15% lower than for primary procedures, but significant improvements are still achievable in most cases.

Minimizing Risks: Pre-Surgery Preparation and Aftercare

Proper preparation before squint surgery and diligent aftercare significantly reduce the risk of complications and enhance outcomes. At London Squint Clinic, we emphasise a comprehensive approach to patient care throughout the surgical journey.

Pre-surgery preparation:

• Thorough assessment: Detailed measurements of the squint in different gaze positions and distances help plan precise surgical adjustments.
• Medical history review: Identifying conditions that may affect healing, such as diabetes, autoimmune disorders, or previous eye surgeries.
• Medication management: Adjusting medications that might increase bleeding risk, such as aspirin or certain supplements.
• Infection prevention: Instructions for using antiseptic eye drops before surgery and maintaining good eyelid hygiene.
• Expectation management: Detailed discussion about realistic outcomes, potential complications, and recovery timeline.

Post-operative aftercare:

• Medication adherence: Strictly following the prescribed regimen of antibiotic and anti-inflammatory eye drops.
• Activity restrictions:
  

  Frequently Asked Questions

  How long does it take to recover from squint surgery?

  Most patients experience initial recovery within 2-3 weeks, with redness and discomfort gradually subsiding during this period. Full healing and stabilization of eye alignment typically takes 6-8 weeks. During the first week, you’ll need to avoid strenuous activities and swimming. Most people can return to work or school after 1-2 weeks, though this varies depending on the complexity of surgery and individual healing rates. Complete neurological adaptation to the new eye position may continue for several months, particularly in adults with long-standing squints.

  What is the success rate of squint surgery?

  The overall success rate for primary squint surgery ranges between 60-80%, depending on the type and complexity of the squint. Simple childhood squints typically have higher success rates (75-80%), while complex cases involving previous surgeries, thyroid eye disease, or nerve palsies have lower success rates (60-70%). Approximately 20-30% of patients may require additional procedures to achieve optimal results. Success criteria include satisfactory cosmetic alignment, elimination of double vision, and improvement in binocular function.

  Is squint surgery painful?

  During surgery, patients are under general anesthesia (or local anesthesia with sedation in some adult cases) and feel no pain. After surgery, most patients experience mild to moderate discomfort rather than severe pain. This typically includes a gritty, scratchy sensation, mild soreness when moving the eyes, and sensitivity to light. Pain is usually well-controlled with regular over-the-counter pain relievers like paracetamol. Severe or increasing pain is uncommon and should be reported promptly as it may indicate complications.

  Can squint return after surgery?

  Yes, recurrence of squint after initially successful surgery is possible. The recurrence rate is approximately 10-20% over 10 years. Factors increasing recurrence risk include certain types of squint (particularly accommodative esotropia), large pre-operative angles of deviation, previous eye surgeries, and underlying medical conditions like thyroid eye disease or myasthenia gravis. Children who have surgery at a very young age (under 2 years) may have higher recurrence rates as they grow. Regular follow-up appointments help detect and manage early signs of recurrence.

  What age is best for squint surgery?

  The optimal timing for squint surgery depends on the type of squint and individual circumstances. For congenital or infantile squints, surgery is typically recommended between 6-12 months of age if the squint is stable and not responding to non-surgical treatments. For acquired squints in children, surgery may be performed at any age once the squint is stable and non-surgical options have been explored. In adults, squint surgery can be performed at any age when indicated, though older patients may have longer recovery periods and slightly lower success rates due to reduced tissue elasticity.

  Will I have visible scars after squint surgery?

  Squint surgery typically leaves minimal visible scarring. The incisions are made on the conjunctiva (the clear membrane covering the white of the eye), which heals with very little scarring. These incisions are hidden beneath the eyelids and not visible during normal eye appearance. Some patients may notice a small area of redness or mild tissue elevation at the incision site for several weeks after surgery, but this usually resolves completely. In rare cases where adjustable sutures are used, tiny temporary marks might be visible on the white of the eye until the sutures dissolve, typically within 2-3 weeks.

  How do I know if I need revision squint surgery?

  You might need revision surgery if you experience persistent or recurrent eye misalignment after your initial procedure. Specific indicators include: noticeable residual squint that affects appearance or self-confidence; persistent double vision beyond the 6-8 week recovery period; return of a squint after initial improvement; development of a squint in the opposite direction (overcorrection); or significant eye alignment issues that affect daily functioning. A comprehensive assessment by a strabismus specialist is necessary to determine if revision surgery would be beneficial, as sometimes non-surgical alternatives like prism glasses or botulinum toxin injections may be more appropriate.