Strabismus surgery for elimination of bifocals in accommodative esotropia

Long-term Ocular Alignment and Sensory Outcomes After Medial Rectus Recession for High AC/A Ratio Esotropia

PURPOSE

To report long-term ocular alignment and sensory outcomes after medial rectus recession for high accommodative convergence/accommodation (AC/A) ratio esotropia.

METHODS

The medical records of consecutive patients who had undergone unilateral or bilateral medial rectus recession for high AC/A ratio esotropia and were observed postoperatively for a minimum of 5 years were reviewed retrospectively.

RESULTS

A total of 34 patients were included. Twenty-three patients (68%) used bifocals preoperatively. The mean age at surgery was 11.5 ± 4.4 years (range: 2.5 to 19.0 years). The mean postoperative follow-up was 7.5 ± 2.3 years (range: 5.0 to 15.25 years). Overall, 21 patients (62%) had surgical success at their last follow-up visit. Age at surgery, preoperative angle of distance and near deviation, distance-near disparity, and preoperative bifocal wear did not predict motor outcome after surgery. Preoperative presence of peripheral binocular single vision was a significant favorable factor for surgical success. At the last follow-up visit, 21% of patients had a recurrence of high AC/A ratio esotropia and 9% each had consecutive exotropia (intermittent [3%] and constant [6%]) and basic esotropia. Peripheral binocular single vision was achieved in 64% of patients and stereopsis in 28%. Bifocal segment was eliminated postoperatively in 70% of patients.

CONCLUSIONS

Nearly two-thirds of patients with high AC/A ratio esotropia achieved a successful long-term motor outcome and peripheral binocular single vision, and nearly one-fourth achieved stereopsis. Recurrence of high AC/A ratio esotropia occurred in some patients, and consecutive exotropia and basic esotropia in a few. Bifocal segment was eliminated postoperatively in 70% of patients. [J Pediatr Ophthalmol Strabismus. 20XX;X(X):XX-XX.].

Outcomes in accommodative esotropia with a high AC/A ratio

PURPOSE

The purpose of this retrospective cohort study was to report the outcomes of high AC/A ratio accommodative esotropia (AET) among children.

METHODS

The medical records of all children <19 years diagnosed with accommodative esotropia and a high AC/A ratio while residing in Olmsted County, Minnesota, from January 1, 1975, through December 31, 2004, were retrospectively reviewed.

RESULTS

A total of 512 patients were diagnosed with AET during the 30-year study period, of which 395 (77.1%) had fully accommodative ET, 117 (22.8%) had partially accommodative ET and 106 (20.5%) had a high AC/A ratio. Of the 93 (87.7 %) high AC/A patients managed with bifocals, 50 (53.8 %) discontinued their use after a mean of 58.7 (range: 5.6-229) months. The Kaplan-Meier rate of discontinuing bifocals was 24.5% at 3 years, 36.4% at 5 years, and 61.4% at 10 years. Patients who discontinued bifocals were more likely to have had strabismus surgery (44% vs 18.6%, p = 0.009) than those who did not discontinue bifocals. The high AC/A patients managed with bifocals achieved similar stereoacuity outcomes to those who did not wear bifocals (p = 0.65) and were no more likely to require surgery (p = 0.13).

CONCLUSION

Among this cohort of children with accommodative esotropia and a high AC/A ratio, bifocal use was discontinued in the majority of children within 10 years, and more commonly among those who underwent strabismus surgery. The use of bifocals was not associated with a higher likelihood of undergoing surgery or enhanced stereopsis compared to those who did not use them.

Surgical outcomes for esotropia in children with high accommodative convergence/accommodation ratio

Purpose

To assess if high accommodative convergence/accommodation (AC/A) ratio impacts surgical outcomes in children with esotropia (ET), and evaluate the appropriate target angle in surgical dosing in the presence of high AC/A ratio.

Methods

A retrospective chart review identified patients who underwent primary bilateral medial rectus (BMR) recessions for ET. Patients were excluded if follow-up was ≤2 months. Basic demographic information, visual acuity, stereopsis, alignment, and target angle for surgery were collected. High AC/A was defined as ≥10 prism diopter (Δ) deviation at near compared to distance. Outcome parameters were near and distance deviations ≤10Δ within orthophoria, and/or stereopsis postoperatively. Yates' continuity correction, unpaired t-test, regression analysis, and one-way ANOVA were used.

Results

We identified 103 patients, 23 with high AC/A and 80 with normal AC/A, preoperatively. Mean age was 4.0 ± 2.5 years. Surgical success measured by postoperative alignment was 48% and 45% in the high AC/A and normal AC/A groups, respectively (P = 1.0). There was a statistically significant difference in preoperative near deviation between high AC/A and normal AC/A groups (P = 0.0015); however, there was no significant difference in preoperative distance deviation (P = 0.061). In addition, there was not a significant difference in preoperative or postoperative stereopsis between high AC/A and normal AC/A groups (P = 0.88 and P = 0.44, respectively). There was a significant difference in the normal AC/A and high AC/A groups when target angle was directed toward preoperative near deviation as determined by one-way ANOVA (F = 170.88, P < 0.0001 and F = 14.61, P = 0.0010, respectively).

Conclusion

In the setting of ET treated with BMR recession, the presence of high AC/A does not affect surgical success as measured by alignment and stereopsis. In addition, when high AC/A is present, surgical dosing with a target angle toward near deviation was found to yield the best surgical outcomes in our patient population.

Modified Y- split and recession of medial rectus muscles in convergence excess esotropia

PURPOSE

The convergence excess esotropia (CEET) is defined when near esotropia is greater than the distance by at least 10 PD while the eye is corrected with the full cycloplegic refraction. The purpose of this study is to evaluate the effect of a modified technique of Y- split recession of the medial rectus muscles on CEET.

METHODS

This was a retrospective study on patients diagnosed with CEET. The surgery included longitudinally dividing the medial rectus muscles into two equal halves and re-attaching them in a recessed and one-tendon width apart position. Success was defined as a residual distance and near esotropia of less than 10 PD and a distance-near disparity of less than 5 PD.

RESULTS

Fourteen patients, including 8 (57.1%) females, were enrolled with a mean age of 7.1 ± 2.9 years. The mean follow-up period was 28.6 ± 12.1 months. The mean preoperative distance and near esotropia was 31 ± 10 and 45 ± 11.3 PD respectively that decreased to 2.4 ± 3 and 3.6 ± 3.8 PD at the final visit (p < 0.001). The Mean distance-near disparity of esotropia was 14 ± 4.5 PD before the operation that decreased to 1.3 ± 1.8 PD at the final visit (p < 0.001). The motor success rate was 78.6%, bifocal glasses were no more required in 92.9% of patients, and stereopsis improved in 35.7% of patients after the surgery.

CONCLUSION

Bilateral modified Y- split and recession of the medial rectus muscle is an effective technique for the treatment of CEET with persistent outcomes in the long-term follow-up.

Effect of prism adaptation in patients with partially accommodative esotropia: clinical findings and surgical outcomes

PURPOSE

To assess the effects of prism adaptation on the surgical outcomes of individuals with partially accommodative esotropia (PAET).

METHODS

The medical records of 51 patients with PAET who were managed surgically at single referral center were retrospectively reviewed. Patients were divided into two groups according to prism adaptation. Data about sex, age, initial angle of deviation, final angle of deviation, stereoacuity, surgical dosage, and follow-up periods were collected. The main outcome of this study was motor outcomes at 12 months.

RESULTS

Eighteen patients had a history of prism adaptation (PA group) and 33 did not (augmented surgery group, AS group). One year after surgery, 12 (66.7%) patients in the PA group and 21 (63.6%) in the AS group achieved an angle of deviation less than 5 PD. The surgical success rate in both groups did not significantly differ (p = 1). After the first prism adaptation test, six patients had an angle of deviation similar to the previous angle; however, 12 patients had larger angle, and consequently required additional prism (prism builder). Two (33.3%) patients who were prism non-builders had deviation less than 5 PD during the final visit. However, among the prism builders, four (57.1%) and five (100%) patients who had prism added once and more than once, respectively, had less than 5 PD deviation during the final visit (p = 0.03).

CONCLUSION

No significant differences were observed in terms of surgical outcomes between both groups. Nonetheless, in PA group, prism builders have better surgical outcomes than non-builders.

The Effect of Prism Adaptation on the Angle of Deviation in Convergence Excess Esotropia and Possible Consequences for Surgical Planning

Convergence excess esotropia describes a heterophoria with binocular single vision (BSV) on distance viewing that becomes esotropic on accommodation upon near fixation. Prism adaptation test (PAT) is a procedure routinely used to reveal the maximum angle of deviation preoperatively for many types of strabismus and has been shown to improve surgical outcomes; however, it is not conventionally used for convergence excess esotropia.

AIM

This study compares the angle of deviation at 1/3 m and 6 m before and after prism adaptation in subjects with convergence excess esotropia to determine if a masked distance angle of deviation can be demonstrated similar to the masked near angle of deviation in some intermittent exotropes. Surgical results are reported.

RESULTS

Fifty-eight children with convergence excess esotropia were prescribed prism adaptation prior to strabismus surgery and 49 met the inclusion criteria. A median increase in the angle of deviation of 20 prism dioptres (PD) was seen at both 1/3 m and 6 m following PAT. These changes were statistically significant (p < 0.001) at both distances. Following one surgical procedure, 83.6% were fully binocular postoperatively.

CONCLUSION

Prism adaptation frequently reveals an otherwise masked large distance angle of deviation in convergence excess esotropia. Convergence excess esotropia can be subdivided into two categories: true and simulated. Those with true convergence excess exhibit a manifest convergent strabismus when viewing a close object and a small, well-controlled latent strabismus upon fixation of a distant object. Those with simulated convergence excess have a comparable near deviation to those with true convergence excess but can be shown to have a distance deviation that approaches the size of the near strabismus once the normal fusional mechanisms are disrupted by a period of prism adaptation.

High AC/A Ratio Esotropia: Do We Really Need to Be Using Bifocals?

INTRODUCTION AND PURPOSE

Most strabismus specialists use bifocals for patients with convergence excess esotropia whose distance deviation is small. While this is a popular treatment modality, there is actually no good data to indicate that this should be considered a standard of care.

PATIENTS AND METHODS

In patients for whom the distance deviation is small enough to allow for the development of binocular vision, my preference is to simply observe these patients. Most will improve with time. For those who do not, or who decompensate, surgery may be indicated.

RESULTS

A careful review of the literature shows a lack of evidence to suggest that bifocals provide an effective treatment for this problem. Some data and theoretical concern may raise a concern over their use. Time and observation may be all that is necessary. There may be a role for surgical correction in these patients as well.

CONCLUSION

While there are theoretical advantages to the use of bifocals in patients with convergence excess esotropia, current data does not support the actual need for active treatment of these patients.

Distance-near disparity esotropia: can we shrink the gap?

Distance-near disparity esotropias are a group of heterogenous usually acquired strabismus disorders, where the angle of misalignment at near exceeds that at distance by 10 prism diopters or more, where the accurate correction of refractive errors and ambylopia are important early objectives. These aetiologically diverse entities respond non-uniformally to strabismus surgery and bifocals. The management challenge is one of 'shrinking' the disparity so that the affected individuals can develop and comfortably maintain binocular single vision and/or optimal alignment. Surgical procedures have continued to evolve but none of the current operative procedures are superior for all patients. Subclassifying this strabismus and highlighting publication data from more homogenous clinical series may assist with the optimisation of future management and treatment outcomes.

Long-term outcome of medial rectus recession and pulley posterior fixation in esotropia with high AC/A ratio

PURPOSE

Medial rectus (MR) recession with pulley posterior fixation (PF) can be used to treatesotropia (ET) with a high accommodative convergence to accommodation (AC/A) ratio as effectively in the short term as MR recession with scleral PF. This study provides a novel examination of the long-term results of MR recession with pulley PF (PPF).

METHODS

In 21 children we performed bilateral MR recession and pulley PF for ET greater at near than distance (high AC/A). Mean follow-up was 3.5 ± 2.5 (standard deviation [SD]) years.

RESULTS

Mean age at presentation was 2.7 ± 1.8 and at surgery 4.3 ± 1.6 years. Fourteen (67%) children had amblyopia. Distance and near pre-operative ET averaged 19.6Δ ± 10.5Δ and 36.9Δ ±18.9Δ, respectively. Mean near-distance (N-D) disparity was 16.4Δ ± 12.3Δ. The MR recession averaged 4.4 ± 0.9 mm. Early mean postoperative ET was 1.3 ± 3.3Δ at distance and 2.8Δ ± 5.2Δ at near. Mean late postoperative ET was 0.1Δ ± 5.8Δ and 1.0Δ ± 6.2Δ at distance and near, respectively. At the final postoperative examination, mean N-D disparity was reduced to 0.9Δ ± 3.6Δ.

DISCUSSION

MR recession with PPF has a high long-term effectiveness, even in patients with amblyopia and autism. Since no posterior scleral suturing is required, it minimizes the perforation risk associated with scleral PF.

CONCLUSION

MR recession with PPF is a safe and highly effective long-term treatment for ET with high AC/A ratio. Long-term results may surpass those of alternate procedures.

Surgery for residual convergence excess esotropia

The outcome of bilateral medial rectus posterior fixation sutures +/- central tenotomy was assessed as a secondary procedure for residual convergence excess esotropia in 11 patients. Ten had previously undergone bilateral medial rectus recessions. One had recess/resect surgery on the deviating eye. The average preoperative near angle was 30 prism diopters with a range of 16 to 45 prism diopters. Eight patients underwent bilateral medial rectus posterior fixation sutures with central tenotomy. Two had bilateral medial rectus posterior fixation sutures only, and one had bilateral medial rectus posterior fixation suture, a lateral rectus resection, and an inferior oblique disinsertion. The postoperative near angle ranged from 4-30 prism diopters, with mean of 12 prism diopters. Five patients demonstrated some stereopsis preoperatively, all needing bifocals. Postoperatively, nine patients demonstrated an improvement in stereopsis, none needing bifocals. Two showed smaller near angles and better control without bifocals. Final stereopsis ranged from 30 seconds of arc to 800 seconds of arc. We feel that bilateral medial rectus posterior fixation sutures with or without central tenotomy is a viable secondary procedure for residual convergence excess esotropia.

The analysis of AC/A ratio in nonrefractive accommodative esotropia treated with bifocal glasses

Purpose

To report the long term results of bifocal treatment in nonrefractive accommodative esotropia and to analyze the changes of accommodative convergence to accommodation (AC/A) ratio.

Methods

Sixteen patients treated with bifocal glasses for at least 5 years were evaluated retrospectively. Angle of deviation at near and distance, refractive error, and AC/A ratio by the lens gradient method were analyzed. The changes of AC/A ratios were also compared after dividing the patients according to continuation or cessation of bifocal therapy.

Results

Six patients (38%; bifocal stop group, BSG) were able to stop using bifocal glasses at an average age of 10.8 years (range, 6.5 to 15.4 years) during their follow-up. However, the other ten patients (62%; bifocal continue group, BCG) had to continue using bifocal glasses until the final visit, which was 13.8 years on average (range, 11.3 to 18.5 years). The AC/A ratio decreased from time of bifocal prescription to the last visit in both groups, from 4.4 to 2.7 in the BSG and from 5.9 to 4.5 in the BCG. AC/A ratios were significantly higher (p = 0.03) in the BCG than that of the BSG from the beginning of bifocal treatment and this difference was persistent until the final visit (p = 0.03).

Conclusions

The AC/A ratio decreased with age in both groups but was significantly higher throughout the entire follow-up period in the BCG. AC/A ratio at bifocal prescription could be an important factor in predicting response to bifocal treatment.

The effect of medial versus lateral rectus muscle surgery on distance-near incomitance

PURPOSE

For strabismus with distance-near incomitance (unequal distance and near deviations), it is customary to select lateral or medial rectus muscle surgery based on whether the deviation is greater at distance or near. The purpose of this study is to examine how this choice between medial and lateral rectus muscle surgery affects distance-near incomitance.

METHODS

Preoperative and postoperative distance and near deviations were obtained from a retrospective review of medical records of consecutive patients who underwent bilateral medial or lateral rectus muscle recessions or resections between January 1, 2000, and June 30, 2007.

RESULTS

A total of 626 procedures were identified. After exclusions, initial procedures included 267 medial rectus muscle recessions that produced an average of 9% more exoshift at near and 159 lateral rectus muscle recessions that produced an average of 34% more esoshift at distance. A larger preoperative distance-near incomitance is associated with a greater reduction in distance-near incomitance with surgery, irrespective of which muscles undergo surgery. Recessions for consecutive deviations and resections for residual deviations exhibited a similar pattern.

CONCLUSIONS

Esotropia tends to be greater at near and exotropia greater at distance fixation. The apparent greater effect of medial rectus muscle surgery on near deviation and lateral rectus muscle surgery on distance deviation is probably an artifact of this difference in preoperative characteristics. Whether a deviation is greater with distance or near fixation may not be a major consideration in choosing between medial or lateral rectus muscle surgery.