Surgical therapy of convergence insufficiency

Convergence insufficiency with diplopia: Surgical treatment in adults

OBJECTIVE

To study the outcomes of treatment with central mini-plication of the medial rectus (MR) muscles in adult convergence insufficiency with diplopia.

METHODS

The study sample comprised 9 cases (7 women). The length of MR plication was collected. Other variables reported were postsurgical deviation, overcorrections in the early postoperative period and at the end of follow-up, final horizontal deviation at near and at distance vision, diplopia, and mean follow-up from surgery. Surgical outcome was considered to be favorable when diplopia and symptoms were resolved and final exotropia at near was ≤8 pd at the end of follow-up.

RESULTS

A central mini-plication of the MR was performed in 9 patients (8 unilateral). Mean (± SD) age was 58.66 (21.39) years. Mean near preoperative deviation: 16.22 (± 2.9) pd and distance preoperative deviation: 6.88 (± 4) pd Overcorrection at distance vision was recorded in 5 cases; this resolved by 3 months postoperatively. There was not overcorrection at near vision except one case. None of the cases operated on had overcorrection at the end of follow-up The final horizontal deviation was ≤8 pd at near vision, except for 3 cases (mean: 6.22). Symptoms and diplopia resolved in 8 cases. The mean follow-up was 10.33 months.

CONCLUSION

Central mini-plication of 1 or 2 medial rectus muscles can improve the symptoms and signs of exotropia associated with convergence insufficiency when exercises and the prisms are rejected by the patients and when these approaches have not solved the problem.

How to Better Treat Patients with Intermittent Exotropia: A Review of Surgical Treatment of Intermittent Exotropia

Intermittent exotropia (X(T)) is the most common form of strabismus, especially in Asians. Treatment of X(T) includes occlusion, overminus lens, and surgery, of which, surgery is the mainstay of treatment. Commonly performed surgical procedures for X(T) are bilateral lateral rectus muscle recession or unilateral lateral rectus recession with medial rectus resection; however, it is unclear which of the two surgeries is more effective. The purpose of this review is to provide an insight on the surgical treatment of X(T). Randomized controlled trials, comparative observational studies, and case series with a large number of patients as well as a long follow-up period of over a year were included.

Comparison between Down Transposition and Slanted Surgery for Bilateral Lateral Rectus Recession in Convergence Insufficiency-Type Exotropia

Purpose: We compared bilateral lateral rectus recession with down transposition and slanted bilateral lateral rectus recession as surgical methods for convergence insufficiency-type exotropia.Methods: We included patients who underwent bilateral lateral rectus recession with down transposition or slanted bilateral lateral rectus recession for convergence insufficiency-type exotropia from January 2012 to January 2021 and observed them for more than 1 year. We retrospectively analyzed sex, age, preoperative best-corrected visual acuity, spherical equivalent, axial length, amount of surgery, and deviation angle before surgery and after surgery (immediately, 1 week, 6 months, and 1 year). We also examined surgical success and stereopsis before surgery and after 6 months and 1 year.Results: The down transposition group included 45 patients and the slanted group included 40. The deviation angle of distance, deviation angle of near and the near-distance disparity (NDD) all decreased in the down transposition group and slanted group 1 year after surgery (1.96 ± 8.77 prism diopter [PD] and 4.60 ± 4.99 PD, respectively; 5.53 ± 9.09 PD and 9.03 ± 9.09 PD, respectively; and 3.58 ± 5.26 PD and 4.43 ± 5.32 PD, respectively). Surgical success after 1 year was 55.6% in the down transposition group and 52.5% in the slanted group, and there was no significant difference between the two groups.Conclusions: In convergence insufficiency-type exotropia, both bilateral lateral rectus recession with down transposition and slanted bilateral lateral rectus recession were effective to correct the deviation angle of near, distance, and NDD. Both are suitable primary surgical methods for convergence insufficiency-type exotropia.

Effects of Bilateral Medial Rectus Resection on Motor Outcomes in Infantile Exotropia

Purpose

To evaluate the effects of bilateral medial rectus resection (BMRres) on motor outcomes in infantile exotropia.

Methods

We evaluated 19 cases of infantile exotropia surgery. The mean age at surgical alignment was 4.8±3.4 years (range, 1.5–11.8 years). The surgical procedures included BMRres (5 cases), BMRres with unilateral lateral rectus recession (ULRR) (3 cases), bilateral lateral rectus recession (BLRR) (8 cases), unilateral lateral rectus recession and medial rectus resection (uniRandR) with contralateral lateral rectus recession (2 cases), and uniRandR (1 case). After dividing the cases into two groups (BMRres group, n=8; other group, n=11), the outcomes at 1 day and at 1, 3, and 6 months after surgery were compared. Surgical outcomes were defined as (1) success: distant esotropia ≤5 prism diopters (^Δ) or exotropia ≤10^Δ, (2) recurrence: exotropia >10^Δ, or (3) overcorrection: esotropia >5^Δ.

Results

Although postoperative distant deviations at 1 day were not different between the two groups, the BMRres group showed smaller distant deviations at 1, 3, and 6 months than the other group (p=0.015, 0.019, and 0.006, respectively). Success rates of the BMRres and other groups were 88% and 73% at 1 day, 100% and 36% at 1 month, 88% and 27% at 3 months, 88% and 18% at 6 months, respectively. Although there were no significant differences between the two groups within 3 months after surgery, surgical outcomes in the BMRres group 6 months after surgery were significantly better than those in the other group (p=0.003).

Conclusion

BMRres is a better procedure than others for infantile exotropia to achieve desirable motor outcomes after surgery.

Surgical outcomes of unilateral lateral rectus recession versus recess-resect in children with convergence insufficiency type intermittent exotropia

To determine the efficacy of unilateral lateral rectus recession (ULR) for convergence insufficiency-type intermittent exotropia (CI-type IXT), we compared surgical outcomes following ULR and recess‒resect (RR) procedures for CI-type IXT. In this retrospective study, medical records of 57 children who underwent ULR (n = 30) or RR (n = 27) for CI-type IXT of less than 25 PD at distance with a postoperative follow-up of 6 months or more were reviewed. Surgical success was defined as an alignment between 10 PD exodeviation and 5 PD esodeviation at distance and near fixation. The postoperative exodeviation showed no significant difference between the two groups at the last follow-up. A significant reduction in the mean near-distance difference was achieved postoperatively in both groups: from 5.4 PD preoperatively to 2.5 at last follow-up after ULR, and from 8.2 to 2.4 after RR (both p = 0.001). However, this difference between ULR and RR was not statistically significant (p > 0.05). The success rate at the last follow-up was 63.3% for ULR and 70.4% for RR (p = 0.574). ULR was found to be an effective treatment for CI-type IXT, with similar surgical outcomes to RR.

Slanted recession on bilateral lateral rectus for the treatment of intermittent Exotropia with convergence insufficiency

Purpose

To evaluate the efficacy and safety of slanted bilateral lateral rectus recession (S-BLRc) for the treatment of convergence insufficiency-type intermittent exotropia (CI-IXT) in children and to probe the relationship of the slanted amount and surgical outcomes.

Methods

Retrospective study. Fifty-eight patients with CI-IXT, aged 4 to 10 years old, underwent S-BLRc procedures. According to the different slanted amount between the upper and lower poles of lateral rectus, all the patients were grouped: Group A (slanting 1 mm, n = 22), Group B (slanting 1.5 mm, n = 18) and Group C (slanting 2 mm, n = 18). The successful surgical outcome was defined as deviation in the primary position ranging from exotropia< 8^△ to esotropia< 5^△ both at near and at distant as well as the near-distance difference (NDD) < 5^△. We analyzed and compared the preoperative and postoperative data including deviations both at near and at distance, NDD, objective torsion, horizontal deviation at up and down gaze, lateral incomitance, binocular vision and surgical success rate among three groups.

Results

The average deviations were significantly decreased from − 37.1^△ ± 4.2^△ (−,exotropia) to − 1.4^△ ± 4.6^△ at near (P < 0.05) and from − 25.8^△ ± 3.7^△ to − 0.1 ± 4.1^△ at distance (P < 0.05). The postoperative NDD on average was significantly reduced from 10.0^△ to 1.8^△ in Group A (P < 0.05), from 11.2^△ to 0.8^△ in Group B (P < 0.05) and from 13.3^△ to 0.9^△ in Group C (P < 0.05). There was a significant difference in the mean corrections of NDD among the three groups (8.2^△ in group A, 10.3^△ in group B and 12.4^△ in group C respectively, P < 0,05). All the patients attained various improvement of stereopsis after surgery. None had torsional diplopia, A-V pattern and lateral incomitance after strabismic surgery. Totally, the surgical success rate was 89.7% in our series at the 6- to 8-month follow-up.

Conclusions

Slanted bilateral lateral rectus recession is an effective and safe procedure for the treatment of CI-IXT in children. S-BLRc can successfully collapse exotropia both at distance and at near, decrease NDD and benefit to gain binocular vision. The correction of NDD was associated with the slanted amount.

Slanted bilateral lateral rectus recession for convergence insufficiency-type intermittent exotropia: a retrospective study

Background

The present study sought to investigate the efficiency and safety of slanted bilateral lateral rectus recession for the treatment of convergence insufficiency-type intermittent exotropia.

Methods

This retrospective study included 34 patients who underwent slanted bilateral lateral rectus recession for convergence insufficiency-type intermittent exotropia in Shandong Provincial Hospital affiliated to Shandong First Medical University between September 2013 and October 2015 with a minimum follow-up of 6 months. A successful surgical alignment was defined as + 5 (positive for esotropia) to − 10 (negative for exotropia) prism diopters (PD) of orthotropia in the primary position while viewing distant or near targets and a near-distance deviation difference ≤ 8PD.

Results

The mean age of the patients at surgery was 7.09 ± 3.80 years (range, 3 to 18 years). The mean distance deviations were − 26.09 ± 6.5 PD (range, − 15 to − 35 PD) and the mean near deviations, − 37.21 ± 6.3 PD (range, − 25 to − 45 PD) preoperatively. The mean recession amount of upper pole of the lateral rectus was 5.97 mm (range, 4.0 to 7.5 mm) and that of lower pole of the lateral rectus, 7.49 mm (range, 6.0 to 8.5 mm). At a mean follow-up of 15.0 months (range, 6 to 37 months), the surgical success rate was 70.6% (24/34), the under-correction rate was 17.6% (6/34), and the overcorrection rate was 11.8% (4/34). The mean near-distance deviation difference was significantly reduced from 11.12 ± 2.06 PD (range, 10 to 15 PD) preoperatively to 2.47 ± 3.04 PD (range, 0 to 10 PD) postoperatively (P < 0.001). Each millimeter of difference between the upper and lower poles of the lateral rectus recession was associated with an improvement of 5.65 PD in the near-distance deviation difference. At the final follow up, a near-distance deviation difference of ≤8PD was found in 32 (94.1%) patients. None of the patients developed A-V pattern, torsional diplopia, or restricted abduction of the eyes.

Conclusions

Slanted bilateral lateral rectus recession may successfully reduce the distance and near exodeviations and the near-distance deviation difference, thus was proved to be an effective and safe procedure for the treatment of convergence insufficiency-type intermittent exotropia.

Central Mini-plication of the Medial Rectus for Convergence Insufficiency

Five cases with a mean (± SD) age of 61 (12.02) years are described to study the outcomes of treatment with central mini-plication of the medial rectus (MR) muscles in adult convergence insufficiency with diplopia and near exotropia: mean preoperative deviation: 18 (± 2) pd. Surgical outcome was considered to be favorable when diplopia and symptoms were resolved and final exotropia at near was ≤8 pd at the end of follow-up. A central mini-plication of the medial rectus (MR) muscles was performed in 5 patients (4 unilateral). Overcorrection at distance vision was recorded in 3 cases; this resolved by 3 months postoperatively. There was not overcorrection at near vision in any case. None of the cases operated on had overcorrection at the end of follow-up. The final horizontal deviation was ≤8 pd at near vision, except for 1 case. Symptoms and diplopia resolved in every case but 2/5 required reoperations. The mean follow-up was 8 (2.12) months. Central mini-plication of 1 or 2 medial rectus muscles can improve the symptoms and signs of exotropia associated with convergence insufficiency when exercises and the prisms are rejected by the patients and when these approaches have not solved the problem.

Do the primary surgical options for basic-type exotropia cause differences in distance-near discrepancy of recurrent exotropia after surgery?

Purpose

Most ophthalmologists appear to have no distinct preference between unilateral recess-resect (R&R) and bilateral lateral rectus (BLR) recessions to treat basic-type exotropia. This study aimed to determine whether differences in distance-near discrepancy and resultant exotropia types of recurrent exotropia following surgery for primary basic-type exotropia exist between the two surgical options.

Methods

Ninety-three patients with recurrent exotropia following BLR recessions for basic-type exotropia (BLR group) and 95 following R&R for basic-type exotropia (R&R group) were included in this retrospective study. The exotropia types in recurrent exotropia were classified into three types according to distance-near discrepancy: basic, divergence-excess, and convergence-insufficiency. The BLR and R&R groups were compared.

Results

After surgery for basic-type exotropia, the type composition changed differently in each group (p < 0.001). The basic-type of primary exotropia was more often maintained in recurrent exotropia in the R&R group than in the BLR group. The incidence of postoperative convergence-insufficiency type exotropia in the BLR group was 28.0% and 8.4% in the R&R group (p = 0.001). Postoperative near stereopsis and fusion control grade of distance deviation did not differ between the two groups (p > 0.05).

Conclusions

Convergence-insufficiency type recurrent exotropia occurred more frequently after BLR recessions than after R&R for basic-type exotropia. The high rate of secondary convergence-insufficiency type exotropia after BLR recessions should be considered when clinicians select a surgical option to treat exotropia.

Comparison of bilateral medial rectus plication and resection for the treatment of convergence insufficiency-type intermittent exotropia

PURPOSE

To compare the clinical outcomes of bilateral medial rectus plication and resection for the treatment of convergence insufficiency (CI)-type intermittent exotropia (IXT).

METHODS

Fifty-five patients with CI-type IXT were included in this prospective study and were followed for 6 months. The patients were randomized into two groups: the bilateral medial rectus plication (BMRP) group (n = 27) and the bilateral medial rectus resection (BMRR) group (n = 28). The eye examinations of each patient were carried out before the surgery and at 1 day and 1, 3 and 6 months postoperatively. The success rate, angle of deviation, stereoacuity, operative time and postoperative conjunctival swelling and redness score were analysed.

RESULTS

The mean deviation at distance at 1 day postoperatively was +6.6 ± 5.6 prism dioptres (PD) in the BMRP group, which was lower than the value of +10.8 ± 9.3 PD observed in the BMRR group (p = 0.046). There was more overcorrection in the BMRR group at first day after surgery. However, there were no significant differences in deviations or success rates were observed between the two groups at 1, 3 and 6 months after surgery (p > 0.05). The operative time in the BMRP (12.9 ± 1.4 min) group was shorter than that in the BMRR (14.7 ± 1.4 min) group (p < 0.001). Postoperative conjunctival swelling and redness were milder in the BMRP group than in the BMRR group (p < 0.001).

CONCLUSION

The BMRP surgery could be an alternative procedure to BMRR for the treatment of CI-type IXT with less immediate postoperative overcorrection and simpler, safer, less traumatic characteristics.

Surgical management of intermittent exotropia: do we have an answer for all?

Intermittent exotropia (X(T)) is one of the most common form of strabismus with surgery being the mainstay of treatment. The main goal of surgery is to preserve binocular vision and stereopsis and to prevent its further loss. The decision to operate is mainly based on four aspects: increasing angle of exodeviation, deteriorating control of X(T), decrease in stereopsis for near or distance and quality of life. Bilateral lateral rectus muscle recession and unilateral lateral rectus recession with medial rectus resection, are the two most common surgical procedures performed and have been studied extensively in basic, divergence excess and convergence insufficiency types of X(T). However, there is no consensus over the relative efficacy of the two procedures in terms of postoperative alignment, residual or recurrent exotropia and consecutive esotropia with widely variable results, which can be attributed to poor understanding of the natural course of the disease. Multiple demographic, clinical and anatomic features that may influence the surgical outcomes have been studied to explain this variability. Moreover, most of the evidence regarding surgical outcomes of X(T) is from retrospective studies and the ongoing randomised prospective trials can shed light on long-term efficacy of these procedures. The goal of this review is to give a comprehensive overview of the outcomes of various surgical techniques in the management of different types of X(T), the preoperative and postoperative factors that may affect the surgical outcomes and to discuss the dilemmas faced by the treating surgeons including the effective management of overcorrection and undercorrection.

Surgical outcomes of three different surgical techniques for treatment of convergence insufficiency intermittent exotropia

PurposeTo determine the outcomes of three different techniques of strabismus surgery in patients with convergence insufficiency intermittent exotropia (CI-X(T)).Patients and methodsSixty-seven patients with CI-X(T) with near-distance disparity (NDD) ≥10 prism diopter (PD) were included in this 1-year follow-up prospective study and were randomly divided into three groups: slanted bilateral LR recession (S-BLR) group in which 22 patients underwent bilateral slanting recession of the lateral rectus (LR) muscle, the I-RR group with 23 patients who underwent improved unilateral medial rectus (MR) resection and LR recession with the amounts of resection and recession biased to near and distance deviation, respectively, and the A-BLR group with 22 patients who underwent bilateral augmented LR recession based on the near deviation. A successful outcome at distant and near was defined as exodeviation between 10 PD of exophoria/tropia and 5 PD of esophoria/tropia. Cumulative probabilities of success, preoperative and postoperative distant, near deviations, and NDD among groups were analyzed and compared.ResultsThe success rate of distant exodeviation, near exodeviation, and NDD in the three groups after 1 year was statistically insignificant (P=0.054, 0.233, and 0.142, respectively). At the 1 year follow-up, vertical pattern strabismus (V and A patterns) was a feature of the S-BLR group, whereas the rate of postoperative overcorrection and undercorrection was significant in the A-BLR and I-RR groups, respectively.ConclusionThe success rate of correction of distant exodeviation, near exodeviation, and NDD was statistically indifferent among the three groups. However, each procedure has its specific postoperative concerns, which should be considered before implementing in patients with CI-X(T).

Type of the recurrent exotropia after bilateral rectus recession for intermittent exotropia

Background

The aim of this study was to investigate the type of exotropia (XT) based on the distance-near (D/N) difference in recurrent XT after bilateral lateral rectus (BLR) recession to treat intermittent XT (IXT) to look into the possibility of secondary convergence insufficiency (CI)-type strabismus.

Methods

A total of 121 patients with recurrent XT after BLR recession for basic-type and divergence excess (DE)-type IXT were retrospectively enrolled at a single institution. The distributions in the XT types were compared according to the D/N difference between primary and recurrent XT.

Results

Preoperatively, the population comprised 14 divergence excess (DE) types and 107 basic types. After the BLR recession, the XT-type composition changed to 59 basic types, 33 CI types, and 29 DE types. In one of the 14 preoperatively identified DE-type XT cases, the XT type changed to CI type, it changed to basic type in four cases, and the remaining nine cases showed no change in the DE type. The 107 preoperatively identified basic-type XT cases postoperatively became 55 basic-type, 32 CI-type, and 20 DE-type recurrent XT cases, and their postoperative distance XT control grades and near stereoacuity values did not significantly differ.

Conclusion

The XT type composition changed after the BLR recession. The XT types in recurrent XT after BLR recession showed an increasing proportion of CI-type. We suspect that an individual fusion mechanism might also influence the XT-type in recurrent XT in view of the somewhat increased DE-type in recurrent XT.

Bilateral lateral rectus muscle recession for the convergence insufficiency type of intermittent exotropia

PURPOSE

To evaluate the surgical efficacy of bilateral lateral rectus recession (BLRR) for intermittent exotropia with convergence insufficiency (CI-type X[T]).

METHODS

The medical records of patients with CI-type X(T) who underwent BLRR on adjustable suture from January 2011 to March 2014 were retrospectively reviewed. Ocular alignment and sensory status were evaluated pre- and postoperatively for each patient. The mean distance and mean near deviation, before and after surgery, as well as the mean near-distance difference, were compared. Success was defined as postoperative alignment of esophoria/tropia of ≤5(Δ) and exophoria/tropia of ≤8(Δ) at distance.

RESULTS

A total of 25 patients were included. The mean exodeviation was significantly reduced, from 32.5(Δ) preoperatively to 0.08(Δ) postoperatively (P < 0.001) at distance and from 45(Δ) preoperatively to 2.4(Δ) (P < 0.001) postoperatively at near. The mean near-distance difference was reduced from 16(Δ) preoperatively to 2(Δ) postoperatively (P < 0.01). Of the 25 patients, 21 (84%) obtained successful motor alignment, 2 had recurrent exodeviation of ≥10(Δ) at distance, and 2 had overcorrected esotropia with deviation angles of >8(Δ).

CONCLUSIONS

In this cohort of patients, bilateral lateral rectus recession using an adjustable suture technique successfully treated CI-type X(T).

Early results of slanted recession of the lateral rectus muscle for intermittent exotropia with convergence insufficiency

The aim of this study was to evaluate the efficacy of slanted recession of the lateral rectus muscle for intermittent exotropia with convergence insufficiency. This prospective study included 31 patients who underwent slanted lateral rectus recession for intermittent exotropia with convergence insufficiency between June 2010 and June 2012. Following parameters were recorded and analyzed: patient sex, age, preoperative and postoperative near and distance ocular alignment, and changes in stereopsis. The mean age of the patients was 9.2 years. The preoperative mean deviation angle was 32.4 PD at distance and 43.4 PD at near. After 6 months, slanted lateral rectus recession reduced the deviation angles to 2 PD at distance and 3.4 PD at near. In addition, the mean difference between distance and near deviation angles was significantly reduced from 11 PD to 1.4 PD at 6 months postoperatively. Slanted lateral rectus recession for intermittent exotropia with convergence insufficiency in children successfully reduced the distance and near exodeviations and the near-distance difference without increasing the risk of long-term postoperative esotropia or diplopia.

Factors associated with the angle of exodeviation in patients with recurrent exotropia

AIMS

To compare preoperative and postoperative distance deviation angle in recurrent exotropes, and to determine factors associated with large-angle recurrent exotropia.

METHODS

In recurrent exotropes who were followed-up more than 2 years postoperatively, the largest angle after recurrence (LAAR) was compared with the preoperative deviation angle (PA). Patients were classified into those who had LAAR<PA and LAAR≥PA. Differences in clinical factors between groups were examined.

RESULTS

Among 242 exotropes who underwent surgery, and followed-up for more than 2 years postoperatively, 83 showed recurrent exotropia. Mean age at surgery was 5.7 ± 2.4 years, and mean postoperative follow-up was 36.2 ± 11.3 months. The bigger the preoperative angle, the bigger the angle of recurrence is. However, the smaller the preoperative angle, the angle of recurrence grows closer to the preoperative one. Only six showed bigger recurrence (LAAR≥PA), and these patients had a smaller mean preoperative angle (p=0.01) compared to patients whose angle of recurrence was smaller than the preoperative one. Among the patients with LAAR<PA, type of exotropia (p=0.03) and preoperative constant deviation (p=0.02) was associated with PA-LAAR≤5(Δ).

CONCLUSIONS

Although the overall incidence of recurrent exotropia with a relatively large angle (LAAR≥PA) is low among patients who underwent surgery for exotropia (2.5%), the possibility of this phenomenon should be noted. The ratio of relatively large angle recurrence was higher in patients with a small preoperative exodeviation and basic type exotropia.

Accommodative ability in exotropia: predictive value of surgical success

PURPOSE

To evaluate the state and symmetry of accommodative response in the two eyes of patients with basic intermittent exotropia and to determine whether accommodative response is a predicting factor to the outcome of unilateral recession-resection procedures or symmetric lateral rectus recessions.

METHODS

Dynamic retinoscopy was performed preoperatively on 47 patients with basic intermittent exotropia with the capacity for fusion who were undergoing a first operation for intermittent exotropia. To obtain a clinical measurement of the degree of binocular accommodative response, the monocular estimate method was used. Patients were divided into two groups: those with an "equal effective accommodative response" and those with an "unequal accommodative response" between the two eyes. Both groups received either unilateral recession-resection procedures or symmetric lateral rectus recessions.

RESULTS

Thirty-two of 47 patients (68%) showed a persistent interocular difference in accommodative amplitude (asymmetric accommodation) of at least 0.75 D. Among these 32 patients with an "unequal effective accommodation," 5 of 14 patients (35.7%) receiving lateral rectus recessions had a satisfactory outcome compared with 13 of the 18 patients (72%) receiving recess/resect procedures (p = 0.039). Of the 15 patients with an "equal effective accommodation," 7 of 8 (87%) receiving recession-resection procedures had a satisfactory outcome compared with 5 of 7 patients (71%) who had lateral rectus recessions (p = 0.57).

CONCLUSIONS

Data suggest that patients with an asymmetric accommodative response benefit more from recession-resection procedures. A decrease in accommodative response of the nondominant eye could be a predicting factor on the outcome of exotropia surgery.

Unilateral recession-resection in children with exotropia of the convergence insufficiency type

PURPOSE

The surgical success rates for intermittent exotropia of the convergence insufficiency type have been reported to be variable, and most were studied retrospectively in adults. The purpose of this study was to evaluate prospectively the long-term surgical results of unilateral lateral rectus (LR) muscle recession and medial rectus (MR) muscle resection in children with intermittent exotropia of the convergence insufficiency type.

METHODS

A total of 14 children with intermittent exotropia greater at near than at distance by 10 prism diopters (PD) or more were included in this prospective study. The amounts of resection and recession were based on near and distance deviation, respectively. Minimum follow-up was 1 year (mean 26.6 months; range, 12-68 months) after surgery. The paired t-test was used to compare preoperative and postoperative measurements of the angle of deviation at distance and near, near-distance difference.

RESULTS

Significant postoperative reduction was achieved in terms of mean distance exodeviation, from 22.5 PD to 9.1 PD (P=0.000), and mean near exodeviation from 33.8 PD to 13.6 PD (P=0.000). Mean near-distance difference reduced from 11.3 PD preoperatively to 4.6 PD postoperatively (P=0.000). Fresnel prism was used temporarily to treat postoperative esotropia in only one patient for postoperative 6 months.

CONCLUSIONS

Unilateral surgery biased to MR strengthening more than LR weakening in children with intermittent exotropia of the convergence insufficiency type, was found to successfully reduce both distance and near deviation and to collapse near-distance differences with a low risk of long-term postoperative esotropia.

The long-term result of slanted medial rectus resection in exotropia of the convergence insufficiency type

PURPOSE

To evaluate the long-term results of slanted medial rectus (MR) resection for intermittent exotropia (X(T)) of the convergence insufficiency type.

METHODS

In all, 10 patients with an X(T) greater at near than at distance by 10 prism diopters (PD) or more were included in this prospective study. Patients received slanted bilateral MR resection. The upper edge of the MR was resected according to the distance exodeviation and the lower edge of the MR was resected according to near exodeviation. The postoperative follow-up period was between 6 and 62 months with a mean of 38.9 months. The paired t-test was used to compare: mean distance angle of deviation preoperatively and postoperatively; mean near angle of deviation preoperatively and postoperatively; and mean near-distance exodeviation difference preoperatively and postoperatively.

RESULTS

Bilateral slanted MR resections reduced mean exodeviation at distance from 23.0+/-7.2 to 16.3+/-5.4 PD (P=0.03); mean exodeviation at near from 34.3+/-7.7 to 24.6+/-6.9 PD (P=0.01); and mean near-distance difference from 11.4+/-2.6 to 8.3+/-3.5 PD (P=0.04). At the final follow-up examination, all patients demonstrated an exodeviation of 10 PD or more at distance and near, and the exodeviation difference between distance and near deviation was within 10 PD in five of the 10 patients. Three patients had an esodeviation at distance after surgery, but all resolved within 4 weeks.

CONCLUSIONS

Bilateral slanted MR resections in patients with X(T) of the convergence insufficiency type resulted in undercorrection in all patients.

Visual complaints from healthy children

It is common for healthy children with specific visual complaints to be seen for eye examinations. After a complete eye examination has ruled out pathologic conditions as the cause of these complaints, it is appropriate for the clinician to explore the possibility that normal entoptic or physiologic visual phenomena might have provoked the child's report of vision problems. Some of these normal visual experiences are frequent causes of children's complaints of vision problems, such as physiologic diplopia, relaxation of the near synkinesis during reading, and vitreous body floaters. Some complaints are common, even though the underlying entoptic or physiologic phenomenon may be speculative or obscure, such as the report that objects look bigger or smaller than they actually are. When the clinician encounters such situations, the parents and the child will be much more satisfied by an explanation of the normal system anatomy and physiology than by the simple reassurance that everything is all right.

Slanted lateral rectus recession for exotropia with convergence weakness

OBJECTIVE

To evaluate the efficacy of slanted recession of the lateral rectus (LR) muscle for exotropia (XT) with convergence weakness.

DESIGN

Predesigned, nonrandomized, comparative trial.

PARTICIPANTS

Twelve study patients and six control subjects with XT greater at near than at distance by > or =10 prism diopters (PD).

INTERVENTION

Twelve consecutive patients underwent slanted LR recession, and six consecutive control subjects underwent standard LR recession.

MAIN OUTCOME MEASURES

Between-groups comparison of the postoperative ocular alignment at distance and near, and the difference between them, as well as the stereopsis.

RESULTS

Slanted LR recession reduced the XT to <8 PD in all patients at distance and in 11/12 patients at near. Additionally, the mean difference between the distance and near exodeviation was reduced from 14+/-4.5 PD preoperatively to 2.9+/-2.4 PD postoperatively. All patients in the control group demonstrated postoperative deviations of <8 PD at distance, but all had residual exodeviations >8 PD at near. Three of the study patients gained gross stereopsis postoperatively.

CONCLUSIONS

Slanted recession of the LR is superior to standard recession in reducing both distance and near XT and in collapsing the difference between them. This technique may also have a positive impact on gross stereopsis.

Unilateral surgery for exotropia with convergence weakness

We prospectively studied 14 patients whom we treated surgically for exotropia (XT) with convergence weakness measuring at least 8 delta for distance (6 m) that increased at least 8 delta at near (1/3 m). Surgery involved lateral rectus recessions and medial rectus strengthenings (advancements or resections) to eliminate distance and near deviations and simultaneously collapse near-distance differences. The medial rectus was strengthened more than the lateral rectus was recessed; amounts were based on the near deviation. Minimum follow-up was 6 months after surgery. Preoperatively, the mean XT at distance was 18.3 delta (range, 8 to 35 delta) and at near 30.1 delta (range, 16 to 50 delta). At latest follow-up evaluations the mean distance deviation was 0.1 delta XT and at near 1.8 delta XT. The near-distance differences were reduced by a mean of 10.2 delta; the mean postoperative difference was 1.7 delta. Unilateral surgery for XT with convergence weakness biased to medial rectus strengthening and geared to near deviation can successfully collapse the near-distance differences while satisfactorily aligning both distance and near fixation. This surgery has low risk of creating long-term postoperative esodeviations at distance.

Unilateral medial rectus resection in the treatment of small-angle exodeviation

Twenty-six patients with small-angle constant or intermittent exotropia of up to 7 degrees, and eight patients with small-angle exophoria of the convergence-insufficiency type, underwent unilateral medial rectus resection. Of the 34 patients, 9 were cured, 19 improved and in 6 surgery failed or there was early recurrence. Improvement occurred usually in patients who had basic microexotropia and in some who had homonymous abnormal retinal correspondence, a factor which limited the sensory results. The sensory, motor, and mechanical factors influencing the procedure are discussed in detail. The resection technique employed is reviewed, demonstrating the advantage of well-controlled results. This paper shows that resecting the medial recti is useful, not only in convergence insufficiency, but also in related small-angle exodeviations, for which a classification is proposed.