Orthoptics in surgical strubismus

Types of Strabismus Surgery

1. Recession: Moving the muscle attachment further back on the eye to weaken its action.

2. Resection: Removing a portion of the muscle to strengthen its action.

3. Muscle Transposition: Changing the position of muscle attachment to alter its function.

4. Adjustable Sutures: A technique allowing fine-tuning of muscle position post-operatively.

Pre-operative Orthoptic Assessment

The orthoptist plays a crucial role in the pre-operative assessment:

1. Detailed Measurements:

   • Measuring the angle of deviation in various gaze positions

   • Assessing versions and ductions

   • Evaluating binocular vision status

2. Sensory Testing:

   • Checking for the presence of suppression or anomalous retinal correspondence

   • Assessing stereopsis

3. Accommodative Function:

   • Evaluating the AC/A ratio

   • Assessing accommodative amplitude and facility

4. Special Tests:

   • Performing forced duction tests

   • Evaluating vertical deviations with head tilt (Parks 3-step test)

5. Patient Education:

   • Explaining the surgical procedure and expected outcomes

   • Discussing potential risks and complications

Surgical Planning

The orthoptist collaborates with the surgeon in planning the procedure:

1. Determining which muscles to operate on based on measurements and test results

2. Deciding on the type of procedure (recession, resection, or transposition)

3. Calculating the amount of surgery needed based on normative data and individual factors

Post-operative Orthoptic Care

After surgery, the orthoptist is involved in:

1. Immediate Post-op Assessment:

   • Measuring the new angle of deviation

   • Assessing ocular motility

   • Checking for any immediate complications

2. Adjustable Suture Management:

   • If adjustable sutures are used, the orthoptist may assist in fine-tuning the alignment

3. Follow-up Assessments:

   • Regular measurements to monitor stability of correction

   • Evaluating binocular vision status

   • Assessing for any delayed complications

4. Vision Therapy:

   • Implementing exercises to enhance binocular vision if appropriate

   • Training fusion and stereopsis

5. Patient Education:

   • Providing post-operative care instructions

   • Explaining expected recovery process and potential for further interventions

Special Considerations

1. Infantile Esotropia: Early surgery (before 2 years of age) is often recommended to maximize binocular potential.

2. Accommodative Esotropia: Surgery is considered only after full optical correction and when a significant residual deviation persists.

3. Intermittent Exotropia: Timing of surgery is crucial and often debated, with some favoring early intervention and others preferring to wait.

4. Vertical Deviations: Often more complex, requiring careful measurement in different gaze positions and head tilts.

5. Adult Strabismus: Can be more challenging due to long-standing deviations and reduced muscle elasticity, but can still yield significant functional and psychosocial benefits.

Potential Complications

The orthoptist should be aware of and monitor for potential complications:

1. Overcorrection or undercorrection

2. Induced vertical deviation

3. Restricted motility

4. Anterior segment ischemia (rare)

5. Diplopia (especially in adult patients)

Conclusion

Surgical intervention in strabismus is a powerful tool for improving ocular alignment and potentially enhancing binocular vision. The role of the orthoptist is crucial throughout the process - from initial assessment and surgical planning to post-operative care and rehabilitation. Close collaboration between the orthoptist and the surgeon ensures optimal outcomes for patients with strabismus.

While surgery can dramatically improve eye alignment, it's important to note that it may not always restore perfect binocular vision, especially in long-standing cases. Continued orthoptic management post-surgery is often necessary to maximize functional outcomes and maintain the benefits of surgical intervention

Note : This document serves educational purposes exclusively and does not constitute medical advice or treatment guidelines