Clinical characteristics and long-term postoperative results of infantile esotropia and myopia

The effects of refractive status on the outcomes of strabismus surgery in patients with esotropia

BACKGROUND

The success of the strabismus surgery can hinge on several factors. One of these factors is refractive condition like hyperopia or myopia. Our study seeks to evaluate the surgical outcomes in patients with esotropia and myopia.

METHODS

This case-control study encompassed all surgical cases of esotropia at Torfe and Negah Hospital between 2016 and 2021, which satisfied our specified inclusion criteria. The initial variables from electronic medical records were collected, including demographic, clinical, and surgery-related factors. At the final follow-up appointment, the level of eye deviation, both at distance and near, was recorded. We considered the operation a "success" for patients with a post-surgery distance eye deviation of 10(Pd) or less. Patients with greater deviation were classified as surgery failure. Statistical analyses were executed using SPSS software (version 16.0), and a P-value less than 0.05 was considered significant.

RESULTS

Of the 194 patients evaluated, 112 were incorporated into the study. Surgical failure was observed in 14.29% of myopic patients, 29.79% of hyperopic patients, and 31.82% of emmetropic patients. The myopia group displayed a 0.19 odd ratio for surgical failure compared to the combined hyperopia and emmetropia groups, not statistically significant (OR: 0.19, CI 95%: 0.03-1.02). Additionally, patients diagnosed with Lateral Rectus Under-action were found to be 6.85 times more likely to experience surgery failure(OR: 6.85, CI 95%: 1.52-30.94). An elevated risk of surgical failure was also identified in patients who underwent Inferior Oblique Weakening procedure, indicated by a 3.77-fold increase in the odds ratio for failure(OR: 3.77, CI 95%: 1.08-13.17).

CONCLUSION

In our study, despite numerical disparities, there was no statistical difference among the success rates of all esotropia patients with different refractive errors. The patients with LRUA or IOOA showed lower success rates. Myopic patients had higher post-op overcorrection with lower reoperation rates compared to hyperopic or emmetropic patients.

Lateral rectus sag and recurrent esotropia in children

PURPOSE

To describe the clinical and intraoperative findings of an anatomic abnormality in children that resembles sagging eye syndrome documented in older adults and that led to recurrent esotropia after surgery.

METHODS

We reviewed records of 4 patients with substantial recurrent esotropia after bilateral medial rectus recession who required subsequent surgery combining lateral rectus resection with correction of the anatomic abnormality affecting the lateral rectus path. Binocular alignment was sequentially analyzed.

RESULTS

Three young patients (2-3 years of age) presented with acquired esotropia but minimal cycloplegic refractive error. The fourth patient (14 years of age) initially had moderate hyperopia and partially accommodative esotropia, but subsequently developed marked bilateral overelevation in adduction. In all patients, esotropia recurred within 5^Δ of preoperative deviation after bilateral medial rectus recession. Surgical exposure demonstrated that bilateral lateral rectus paths were inferiorly displaced more than one-half tendon width from their normal paths near the globe's equator, despite normal scleral insertions. Equatorial myopexy and lateral rectus resection resulted in stable esotropia correction.

CONCLUSIONS

Lateral rectus sag in children creates a type of acquired esotropia and overelevation in adduction poorly responsive to standard surgery but correctable with lateral rectus resection and equatorial myopexy that normalizes the lateral rectus path through permanent scleral fixation.

Comitant strabismus: Perspectives, present and future

Comitant strabismus is a common condition affecting infants, children and adults. Its impact on the affected patient may be severe resulting in visual loss, lack of binocularity, diplopia, social stigma and multiple corrective surgeries within the affected individual's lifespan. It is therefore important that this prevalent disorder should be better understood. We review the current understanding of the demographics and what is known of the etiology, risk factors and genetics of strabismus. We stress the importance of careful clinical assessment in classifying strabismus, and the common pitfalls in the measurement and pre-operative sensory work-up of the strabismic patient. The fact strabismus is comitant does not indicate it is benign: acute onset of comitant esotropia may be a presenting sign of pontine or cerebellar tumor. Lastly, we review the impact of genetics on our understanding of strabismus. While the causes of many types of congenital incomitant strabismus have been elucidated through careful observation and genetic screening, the genetics of comitant strabismus are more complex and multifactorial. Only through careful study and recruitment of large groups of affected individuals and families can we start to answer the question: why is this group of patients pre-disposed to develop strabismus. Doing so will help identify patients at risk, to spare them from the significant morbidity associated with this common disorder.

Computer-assisted dosage calculation for strabismus therapy in myopic patients

PURPOSE

The published dosage recommendations for the surgical correction of horizontal strabismus in non-myopic patients show large, unexplained differences. For patients with high myopia, the situation becomes even more complex because the increase in the size of the bulb also affects the geometry of the oculomotor muscles. In this study, we wanted to investigate whether computer simulations of the oculomotor plant can be used to find accurate surgical parameters.

METHODS

In a retrospective study, we investigated pre- and postoperative strabismus patterns in 13 patients affected by convergent (seven patients) or divergent (six patients) strabismus and high myopia. Postoperative checks were made 1 day, 1 week, 3 months and 1-6 years after the operation. For each patient, we simulated the presurgical strabismus pattern with SEE++ (see 'Further Information' for manufacturer details), a biomechanical simulation program of the oculomotor plant. The individual results of the simulations were then compared to the measured postoperative strabismus patterns.

RESULTS

We found a trend of under-correction in the postoperative situation, resulting in four patients having a large remaining strabismus angle of more than 5 degrees. The computer simulations were able to reproduce this under-correction, and suggested an increase in dosage.

CONCLUSION

We conclude that realistic biomechanical simulations of the oculomotor plant can predict the postoperative result for myopic patients accurately. The results of the computer simulation correlate well with the postoperative outcome of the patient.