Surgical outcome after prism adaptation for esotropia with a distance-near disparity

Prism adaptation test before strabismus surgery in patients with decompensated esophoria and decompensated microesotropia

Purpose

To evaluate the effect of Prism adaptation test (PAT) on the angle of squint in decompensated esophoria (decEPH) and decompensated microesotropia (decMET).

Methods

In this single-center retrospective study we reviewed the medical records of patients with the diagnosis of decEPH or decMET, aged at least 12 years, who were treated by strabismus surgery for the first time. The maximum Angle of squint (AOS) for far (F) and near (N) fixation and PAT results before surgery, as well as AOS (F) and AOS (N) after surgery and results of binocular function tests were considered. PAT included wearing a prism based on the largest angle for over 60 min.

Results

100 patients (mean age 37 ± 17 years) were included in the decEPH group, 82 patients (mean age 30 ± 13 years) in the decMET group. For decEPH, before surgery AOS was 25.5 ± 8.8 pdpt (F) and 23.5 ± 9.8 pdpt (N). During PAT the AOS increased significantly by 2.7 ± 4.3 to 28.2 ± 8.6 pdpt (F) and by 4.9 ± 4.5 to 28.3 ± 9.5 pdpt (N). Altogether, in 82% of decEPH patients AOS (F) and/ or AOS (N) in- or decreased by at least 3 pdpt. For decMET, before surgery AOS was 28.6 ± 10.8 pdpt for far (F) and 30.9 ± 11.8 pdpt for near fixation (N). During PAT the AOS increased significantly by 4.2 ± 5.8 to 32.5 ± 9.5 pdpt (F) and by 3.7 ± 6.1 to 34.4 ± 9.5 pdpt (N). Altogether, in 51% of decMET patients, AOS (F) and/ or AOS (N) increased by at least 10 pdpt, therefore more than 5° which would have been maximally expected from mictrotropia, or decreased by at least 3 pdpt.

Conclusions

The Prism adaptation test (PAT) showed remarkable changes in AOS in both decEPH and decMET. In patients with decEPH, the preoperative assessment of the “true AOS” under PAT reflects a pivotal requirement for successful strabismus surgery, as 82% had dose relevant angle changes ≥ 3 pdpt. For patients with decMET the preoperative prism adaptation test is especially of diagnostic value, but also 51% of decMET patients had changes in AOS beyond the expected microtropic angle (≥ 10 pdpt) or even a dose relevant angle decrease (≥ 3pdpt).

Clinical Characteristics of Patients with Intermittent Exotropia According to the Response to Short-term Prism Adaptation Test

Purpose

To evaluate the prevalence of the prism adaptation response in patients with intermittent exotropia (IXT) using the short-term prism adaptation test (PAT) and to assess factors associated with prism adaptation response in IXT patients.

Methods

A case-controlled retrospective analysis was performed on 113 patients with IXT without prior surgical treatment. Age, sex, visual acuity, refraction, stereoacuity, control scale, type of exotropia, history of occlusion, and presence of accompanying visual symptoms were recorded. Prism alternate cover test (PACT) was performed with fixation targets at 6 m and 1/3 m. All patients underwent short-term PAT wearing prism glasses that offset the exodeviation previously measured by PACT. After 30 minutes, angle deviation was measured, and patients were classified into either an increase group, which had an increase in deviation ≥5 prism diopters after short-term PAT, or a no-change group. Analysis was performed to investigate the clinical factors influencing the increase in exodeviation after short-term PAT.

Results

Fifty patients (44.2%) showed an increase ≥5 prism diopters during distance or near fixation after short-term PAT compared to the previous PACT: 12 patients (10.6%) showed an increment at distance fixation, and 45 patients (39.8%) showed an increase at near fixation. At distance fixation, the increase-group had a significantly smaller maximum angle measured by PACT. At near distance, age at PAT, maximum distance angle, minimum distance angle, maximum near angle, minimum near angle, angle fluctuation at near, and IXT type showed significant associations with positive short-term PAT response. In the multivariate analysis, older age and smaller maximum near angle were significantly associated with positive short-term PAT response at near fixation.

Conclusions

Short-term PAT could be helpful in older IXT patients with a small maximum angle of deviation at near fixation to mitigate the vergence aftereffect and show the maximum angle of deviation.

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.

Comparison of the therapeutic effects of surgery following prism adaptation test versus surgery alone in acute acquired comitant esotropia

BACKGROUND

To compare the therapeutic effects of surgery following prism adaptation test versus surgery alone in acute acquired comitant esotropia (AACE).

METHODS

A total of 46 patients with AACE were enrolled in this retrospective study. Among them, 26 patients underwent surgery following prism adaptation test (combination group) and 20 patients underwent surgery alone (surgery group). The following parameters were evaluated including success rate, distant and near deviation angles, visual function, and near stereoacuity.

RESULTS

There were no significant differences in success rate between the combination group and surgery group at post-treatment 12 months (96.15% vs. 90.00%, p > 0.05). The postoperative distant and near deviation angles in two groups were significantly lower than that before surgery (p < 0.05). In addition, the numbers of patients with stereopsis postoperatively in two groups were significantly higher than that before surgery (all p < 0.05). Moreover, the numbers of patients with stereopsis and central stereopsis in the combination group were significantly higher than that in the surgery group postoperatively. At post-treatment 12 months, one (3.85%) case recurred in combination group and three (15.00%) cases in the surgery group. No complications were observed in the two groups.

CONCLUSIONS

Both approaches had therapeutic benefit in AACE. Surgery following prism adaptation test had better treatment benefits than surgery alone in improving binocular function and reducing recurrence rate.

Amblyopia in High Accommodative Convergence/Accommodation Ratio Accommodative Esotropia. Influence of Bifocals on Treatment Outcome

PURPOSE

To study the influence of bifocal use on amblyopia treatment outcome in high accommodative convergence/accommodation (AC/A) ratio accommodative esotropia with deviation only at near.

DESIGN

Retrospective comparative case series.

METHODS

Setting: Tertiary referral center.

PATIENTS

Children with high AC/A ratio accommodative esotropia aged 3-8 years old, with deviation only at near with glasses, neutralized with bifocal lenses (follow-up 1 year).

INTERVENTION

Amblyopia was treated with patching. We compared bifocal and single-vision glasses users at 6 months and 1 year, with control of potential confounding variables (multiple regression).

MAIN OUTCOME MEASURES

LogMAR lines of improvement in visual acuity of the amblyopic eye, and improvement in stereoacuity.

RESULTS

Of 78 children, 61 were eligible. All patients wore single-vision glasses for 2 months (baseline visit), 46 of them changed to bifocals. Of 27 initially amblyopic children, 21 remained amblyopic at 2-month baseline (13 of them changed to bifocals). After adjustment for initial deviation, refraction, age, and amblyopia, improvement of visual acuity in the amblyopic eye was larger in the bifocal vs single-vision group at 6 months (mean 2.6 [95% confidence interval (CI): 1.9-2.9] logMAR lines vs mean 1.9 [95% CI: 0.5-2.2] logMAR lines, respectively, P = .01), but not at 1 year (mean 2.7 [95% CI: 2.2-3.1] logMAR lines vs mean 2.3 [95% CI: 1.6-3.1] logMAR lines, respectively, P = .3). Improvement of stereoacuity was not significantly different between the 2 groups.

CONCLUSIONS

Use of bifocals may provide a transient advantage, but improvement in visual acuity and stereopsis is equal with single-vision glasses over time.

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.

Accommodative esotropia: the state of the art

PURPOSE

To review the state of the art of Accommodative Esotropia (AE) through careful study of what has been reported up to the point in literature.

METHODS

A literature search was done on PubMed using key words including "Accommodative esotropia", "Infantile esotropia", "Strabismus" and "Accommodation". We systematically reviewed and critically appraised what has been written about AE and we tried to analyze that according to the current management of AE.

RESULTS

Accommodative Esotropia (AE) is a form of strabismus characterized by convergent misalignment of the visual axes that can be associated with hyperopia and abnormal fusional divergence. Also abnormal accommodative convergence/accommodation ratio could be found. In lots of cases, AE initially presents as an intermittent esodeviation at age 1.5 to 4 years. The prevalence of AE has been estimated near 1-2% in the United States. The only treatment with an optical correction usually is successful in re-establishing alignment, but surgical correction is necessary in approximately 30% of cases.

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.

Medial rectus muscle pulley posterior fixation sutures in accommodative and partially accommodative esotropia with convergence excess

BACKGROUND

The use of medial rectus pulley posterior fixation sutures to treat esotropia with convergence excess has limited support in the literature. We describe our results using this technique to treat patients with large near-distance disparities.

METHODS

We retrospectively analyzed records of patients with accommodative or partially accommodative esotropia and convergence excess 13(Δ) or greater treated with bilateral medial rectus muscle recessions augmented by pulley posterior fixation. Surgical doses of recessions were calculated for the mean of distance and near deviations. Primary outcome measures were ocular alignment at distance and near and near-distance disparity.

RESULTS

A total of 26 patients were identified by the record review. Mean age at surgery was 5.4 years (range, 1.8-11.0 years) and mean follow-up time 12.7 months (range, 1.0-37.6 months). Mean preoperative distance esotropia was 22.9(Δ) (range, 0(Δ)-53(Δ)), with a mean near-distance disparity of 26.4(Δ) (range, 13(Δ)-53(Δ)). At 1 to 3 months postoperatively, mean distance deviation was 0.5(Δ) exotropia (range, 18(Δ) exotropia to 12(Δ) esotropia), with a statistically significant decrease in mean near-distance disparity to 4.5(Δ) (range, 0(Δ)-26(Δ); P < 0.001). Three-quarters of patients (77%) achieved 0(Δ) to 9(Δ) esotropia at 1 to 3 months, with 4 overcorrections for distance and 2 undercorrections for distance and near. At final follow-up 2 patients had persistent exotropia less than 10(Δ).

CONCLUSIONS

Augmentation of bilateral medial rectus recessions with pulley posterior fixation resulted in a significant decrease in near-distance disparity in this group of patients with accommodative and partially accommodative esotropia and convergence excess, with a low rate of persistent overcorrection for distance.

Functional benefits of sensory and motor evaluation before strabismus surgery

Evaluating the sensory and motor status of your strabismus patient is an important part of the preoperative examination. However, not all clinicians follow the same protocol for this assessment. Many rely on personal experience to determine what tests to do. Is this enough? Interpreting the evidence regarding the proper preoperative exam for strabismus patients and incorporating it into your practice can help to enhance your postoperative results.

Strabismus surgery for elimination of bifocals in accommodative esotropia

PURPOSE

This study reports the outcomes of strabismus surgery to eliminate bifocals in patients with accommodative esotropia with a high accommodative convergence to accommodation (AC:A) ratio.

DESIGN

Retrospective interventional case series.

METHODS

Sixteen patients who wore bifocals for treatment of accommodative esotropia with a high AC:A ratio underwent strabismus surgery following prism adaptation testing (PAT) for the near angle of esotropia without bifocals. Outcomes were considered successful if patients had microtropias and maintained fusion without bifocals.

RESULTS

All patients had successful outcomes after one or two surgeries. Three of 13 (23%) patients with positive PATs required two surgeries. Two of three (67%) patients with negative PATs required two surgeries. Binocularity remained the same in 13 patients and improved in three patients. Glasses were eliminated entirely in eight of 16 (50%) patients.

CONCLUSIONS

Strabismus surgery may eliminate the need for bifocal glasses in patients with accommodative esotropia with a high AC:A ratio, with many patients able to discontinue glasses entirely. Preoperative PAT may help predict the risk of requiring more than one surgery.

Medial rectus pulley posterior fixation is as effective as scleral posterior fixation for acquired esotropia with a high AC/A ratio

PURPOSE

To compare traditional medial rectus (MR) scleral posterior fixation versus MR pulley posterior fixation without scleral sutures for the treatment of acquired esotropia (ET) with a high accommodative convergence over accommodation (AC/A) ratio.

DESIGN

Nonrandomized interventional case series.

METHODS

Medical records were retrospectively reviewed for twenty-two patients who underwent bilateral MR posterior fixation for acquired ET with a high AC/A ratio, with or without associated MR recessions. The main outcome measure was the reduction in distance-near disparity created by MR scleral posterior fixation compared with MR pulley posterior fixation.

RESULTS

Nine patients underwent MR scleral posterior fixation surgery, seven in combination with MR recessions for distance ET. Postoperatively, the distance-near disparity decreased an average of 11.8 prism diopters, stereoacuity improved in six patients, and eight patients no longer needed bifocals. Thirteen patients underwent MR pulley posterior fixation surgery, 10 in combination with MR recessions for distance ET. Postoperatively the distance-near disparity decreased an average of 14.4 prism diopters, stereoacuity improved in eight patients, and 12 patients no longer required bifocals. Statistically, the two procedures were equivalent. One patient in each group was undercorrected at near only, with the residual near ET controlled with bifocals. One patient who underwent MR pulley posterior fixation combined with large MR recessions was overcorrected at distance only.

CONCLUSION

Traditional MR scleral posterior fixation and MR pulley posterior fixation are equally effective in treating acquired ET with a high AC/A ratio.

Prism adaptation in visually mature patients with esotropia of childhood onset

OBJECTIVE

To investigate the role of prism adaptation in the visually mature population with esotropia onset before visual maturation.

DESIGN

Retrospective, noncomparative case series.

PARTICIPANTS

Eighty-five patients, 26 prism adapted for near (PAN) and 59 prism adapted for distance (PAD), were included in the study.

METHODS

Patients included in this study were older than 9 years and had esotropia with an onset before age 9. Mean follow-up was 30 months (range = 6 weeks-164 months). All patients had prism adaptation and subsequent surgical correction. Surgical success was defined as peripheral fusion on the Worth 4-dot test and < or = 8(Delta) deviation at near and distance on the simultaneous prism and cover test.

MAIN OUTCOME MEASURES

Response to preoperative prism adaptation and postoperative alignment and sensory results were examined.

RESULTS

Twenty-six of the 85 patients had previous surgical esotropia correction. In the PAD group, 41 were responders. Seventeen of these had built their deviation > or = "0" > 10(Delta) with prism adaptation. All responders had surgery for their prism-adapted angle. Postoperatively, 34 of 41 (83%) responders and 6 of 18 (33%) nonresponders had fusion. In the PAN group, 17 were responders. Nine of these built their deviation with prisms. Postoperatively, 16 of 17 (94%) responders and builders and 1 of 9 (11%) nonresponders had successful surgery with sensory and motor fusion.

CONCLUSIONS

Adults with esotropia onset before visual maturation can be prism adapted and surgically treated with a predictable outcome of sensory and motor fusion. Those prism adapted for near with response can be successfully treated with surgery for the near deviation. Prism adaptation also aids in determining those who would benefit from larger amounts of surgery.