The Benefits, Risks, and Efficacy of Strabismus Surgery in Adults

Divergence excess and basic exotropia types of intermittent exotropia: a major review. Part 2: non-surgical and surgical treatment options

INTRODUCTION

Currently, there is no consensus regarding the management of intermittent exotropia (IXT), which includes both surgical and non-surgical treatment options. Nonsurgical management of IXT has been suggested and includes watchful observation, patching, overminus lenses, prism, and vision therapy/orthoptics. While a significant portion of IXT patients are treated by surgery, it is reported that there is a substantial tendency for reoperation or recurrence of IXT. This paper provides a comprehensive review of non-surgical and surgical treatment options for the IXT.

METHODS

Search strategies involving combination of keywords including intermittent exotropia, divergence excess, basic exotropia, refractive error, glasses, spectacles, natural history, untreated, observe, occlusion, patch, overminus, overcorrecting minus, prism, vision therapy, orthoptic, anti-suppression, fusion exercise, and surgery were used in Medline. All English articles from 01/01/1900 to 01/09/2020 were reviewed. The reference list of the identified articles was also checked for additional relevant articles. Studies focused on animal models or strabismus associated with neurologic disorders or injury were excluded. The following filters were used for surgical management due to the abundance of reports: full text, randomized controlled trial, review, in the last 5 years.

RESULTS

Appropriate optical correction of refractive error is generally the starting point for all management approaches, but there is a lack of randomized clinical trial data regarding this treatment modality. Randomized clinical trial data indicate that both observation and occlusion are reasonable management options for children 3-10 years old, and there were insufficient data to recommend occlusion for children 12-35 months old. While overminus lenses were found to improve the control of IXT when assessed wearing overminus spectacles, this improvement did not persist after the treatment ended. The result of the only randomized clinical trial on the effectiveness of base-in prism indicated that this treatment is no more effective than nonprism spectacles for improving control. A recent randomized clinical trial showed that vision therapy/orthoptics is effective in improving the control of IXT when compared to observation alone. Surgery was found to alter a number of clinical characteristics of IXT, including reducing the distance and near angle of deviation, reducing photophobia, improving health-related quality of life, stereopsis, and the Newcastle Control Score. However, there are no randomized clinical trial data comparing surgery with a control group such as placebo or a no treatment observation group.

DISCUSSION

Rigorously designed clinical trials to investigate the effectiveness of non-surgical and surgical treatments for intermittent exotropia are needed.

The comparison of postoperative changes in subjective awareness of exodeviation between pediatric and adult patients with intermittent exotropia

To evaluate pre- and postoperative changes in the subjective awareness of exodeviation in patients with intermittent exotropia and compare pediatric and adult patients. This retrospective study included pediatric (6-17 years) and adult patients (≥18 years) with intermittent exotropia who underwent surgery. Patients with subjective awareness of exodeviation associated with exotropia were included. Postoperative improvement was defined as a decrease in the subjective awareness of exodeviation and alleviation of associated symptoms after surgery. Changes in subjective awareness of exodeviation after surgery were evaluated and compared between pediatric and adult patients. Clinical factors associated with postoperative improvement in subjective awareness of exodeviation were analyzed. A total of 195 patients (159 pediatric and 36 adult) were included. Among the included patients, 145 (74.4%, 145/195) reported postoperative improvements in their subjective awareness of exodeviation. A lower percentage of adult patients (15/36, 41.7%) showed postoperative improvement in subjective awareness of exodeviation than that of pediatric patients (130/159, 81.8%, P < .001). The level of distant control was significantly associated with postoperative improvement in subjective awareness of exodeviation in adult patients (odds ratio, 1.151; 95% confidence interval, 0.030-0.758; P = .022). There was a significant difference in the postoperative change in the subjective awareness of exodeviation between pediatric and adult patients with intermittent exotropia. Adult patients are less likely to exhibit postoperative improvement in subjective awareness of exodeviation than pediatric patients. Adult patients with a better level of distant control are more likely to show postoperative improvement in their subjective awareness of exodeviation.

Short-Term Morpho-Functional Changes before and after Strabismus Surgery in Children Using Structural Optical Coherence Tomography: A Pilot Study

PURPOSE

To evaluate the immediate alterations in the thickness of the macular ganglion cell-inner plexiform layer (mGCIPL), peripapillary retinal nerve fiber layer (RNFL), inner retinal layer (IRL), and outer retinal layer (ORL) using spectral domain optical coherence tomography (SD-OCT) subsequent to strabismus surgery in pediatric patients diagnosed with horizontal esotropia.

METHODS

Twenty-eight eyes from twenty-one child patients who had undergone uncomplicated horizontal rectus muscle surgery due to strabismus were included. Measurements of RNFL, mGCL-IPL, IRL, and ORL using structural OCT were conducted both before the surgery and one month after the surgical procedure. Importantly, a control group comprising 14 healthy eyes, matched for age and significant refractive error (<3.00 diopters), was included in the current analysis.

RESULTS

Our analysis indicated no significant disparity before and after surgery in terms of best-corrected visual acuity (BCVA), RNFL, IRL, and ORL. Conversely, concerning the macular ganglion cell layer-inner plexiform layer analysis, a substantial increase in mGCL-IPL was observed following the surgical intervention. The mean mGCL-IPL measured 60.8 ± 9.2 μm at baseline and 66.1 ± 13.2 μm one month after the surgery (p = 0.026). Notably, comparison between the strabismus group at baseline and the healthy group revealed a significant reduction in mGCL-IPL in the strabismus group (60.8 ± 9.2) compared to the healthy control group (68.3 ± 7.2; p = 0.014).

CONCLUSIONS

Following strabismus surgery, our observations pointed towards a thickening of the mGCL-IPL layer, which is likely attributable to transient local inflammation. Additionally, we identified a significant differentiation in the mGCL-IPL complex between the pediatric patient group with strabismus and the control group.

Binocular Function in Adults before and after Strabismus Surgery

PURPOSE

To evaluate the state of binocular vision, the amount and direction of the ocular deviation before and after strabismus surgery in adult patients and to monitor the occurrence of postoperative complications.

METHODS

The retrospective study of 58 adult patients with selected types of strabismus who were surgically treated in the Eye Department of the Tomas Bata Regional Hospital in Zlín. We evaluated the amount and the degree of the primary ocular deviation and the binocular alignment before and after surgery,  as well as the state of binocular vision after surgery and the occurrence of postoperative complications.

RESULTS

The average deviation in convergent strabismus before surgery was +23.46 degrees, after surgery +6.6 degrees, in divergent strabismus it was -21.5 degrees, after surgery -1.48 degrees, for vertical strabismus before surgery +12.5 degrees and +3.75 degrees after surgery and in paralytic strabismus +20 degrees before surgery and +3 degrees postoperatively. Preoperatively there was effectively no binocular vision in up to 63.9% of patients, superposition occurred in 31%, fusion in 5.1%. No patient had stereopsis before surgery. After surgery, superposition was present in 39.7%, fusion in 31% and stereopsis in 6.9% of patients. Only 22.4% of patients experienced no binocular vision after surgery. Of the selected 21 patients out of 58 with an observation period of at least 3 years, we observed an improvement or development of binocular vision functions after surgery in 12 patients and no improvement of binocular vision functions in 9 patients. In the first group, 58.3% had a stable deviation throughout the follow-up period. While in the second group the deviation was stable in only 33.3%. We can assume that the improvement in binocular vision function after strabismus surgery, leads to a greater longer-term stability of postoperative deviations.

CONCLUSION

Strabismus surgery in adult patients is an effective and safe method, which is not only a cosmetic procedure used to adjust the position of the eyes, but also enables us to induce or improve the state of binocular vision functions.

Scleral Perforation as a Complication of Strabismus Surgery: A Literature Review

The aim of this review was to report the existing literature on the incidence, risk factors, treatment, and outcomes of scleral perforation as a vision-threatening complication of strabismus surgery. The current literature reported an incidence range of scleral perforation/penetration between 3 in 1,000 and 7.8%. Rectus muscle recession was the most commonly mentioned risk factor among the studies. Other risk factors were myopia, previous extraocular muscle surgery, surgeon experience, S-24 needle use, muscle reattachment posterior to the original insertion site, operating on a horizontal rectus muscle, and young age. Different views existed in the literature regarding scleral perforation management. Some ophthalmologists advocated management by cryopexy or indirect ophthalmoscopic laser uniformly, whereas others reserved it for more complicated cases. Antibiotic therapy for endophthalmitis prophylaxis was recommended by one study and shown to be practiced by some ophthalmologists. [J Pediatr Ophthalmol Strabismus. 2022;59(4):214-223.].

Effects of corrective strabismus surgery on social anxiety and self-consciousness in adults

PURPOSE

To report the results of a questionnaire-based interventional study to evaluate the effects of strabismus surgery on private self-consciousness, public self-consciousness, and social anxiety using a validated self-consciousness survey instrument.

METHODS

Patients who underwent strabismus surgery completed a demographics and a self-consciousness scale form both pre- and postoperatively. The total and subscale (private self-consciousness, public self-consciousness, and social anxiety) summative scores were compared using the Wilcoxon signed-rank test, with statistically significant relationships defined as P < 0.05. Total and subscale summative scores were analyzed as such and by strabismus type, years of education, and marital status.

RESULTS

Overall improvement was found postoperatively in total scores (P = 0.012), public self-consciousness scores (P = 0.009), and social anxiety scores (P = 0.028). Although improvement was noted for the private self-consciousness subscale (P = 0.188), it did not reach statistical significance. Subdivided according to strabismic and demographic subgroups, significant improvement was only noted in esotropic patients, college graduates, married/living partner/widowed patients, and separated/divorced patients.

CONCLUSIONS

This study suggests that beyond functional and cosmetic improvements, strabismus surgery can result in improved public self-consciousness and social anxiety, with greatest effect noted in esotropic, college graduates, and nonsingle patients.

Late Surgical Correction of Longstanding Constant Strabismus in Adults: Is Fusion Possible in All Successfully Aligned Patients?

PURPOSE

To determine whether late surgical correction provides fusion in adults who have constant strabismus beginning in early childhood.

MATERIALS AND METHODS

This was a prospective study that included 34 consecutive adults with a history of early onset strabismus who had not previously undergone surgery. They were tested with the Bagolini striated glasses (BSG), Worth four-dot (W4D) test, cover test, and four-prism diopter (4-PD) test, preoperatively, and 6 weeks after surgery.

RESULTS

The mean age was 23.8 years, 17 patients had esotropia and 17 patients had exotropia. Preoperatively, all patients demonstrated a manifest horizontal deviation ranging from 30^∆ to 60^∆ and had suppression. At 6 weeks postoperatively, 33 patients had a horizontal manifest deviation of <15^∆ (range, 2^∆-14^∆; median, 6^∆), and none were orthotropic as determined by the cover test together with the 4-PD test. All of these 33 patients achieved anomalous retinal correspondence (ARC) with the BSG at near, and 25 (75%) had ARC with the W4D test at near.

CONCLUSIONS

Although our study has limited number of patients its findings suggest it is possible to develop ARC after surgery in almost all adult patients with childhood-onset strabismus associated with suppression, and who have not previously been operated upon, if satisfactory alignment is achieved in adulthood.

The Functional Benefits of Strabismus Surgery

When performed prior to visual maturity, strabismus surgery can result in the development or recovery of binocularity. When strabismus surgery is performed after visual maturity, the functional benefits of the surgery should be dichotomized according to whether the onset of the strabismus was before or after visual maturity. If the onset was after visual maturity, patients typically are diplopic. Specific success rates for eliminating diplopia vary according to the nature of the strabismus; however, overall the success rate is quite high. There is a common misperception that surgery in adults for strabismus that began prior to visual maturity is merely cosmetic. Numerous studies contradict this misconception. Even if the strabismus has been longstanding, most adults will experience some improvement in binocular function after strabismus surgery. In esotropic patients, this improvement typically takes the form of an expansion of binocular visual fields; however, some patients may also regain stereopsis. There are many psychosocial benefits to adult strabismus surgery. This is reflected in the finding that the majority of adults surveyed with strabismus would trade a portion of their life expectancy to be rid of their strabismus.

Surgical Treatment of Adult-Onset Esotropia: Characteristics and Outcomes

PURPOSE

To describe the characteristics of the strabismus, surgical management, and outcomes of patients who underwent surgery for adult-onset esotropia.

METHODS

This was a retrospective case study of patients at an academic tertiary referral center who underwent surgical treatment of esotropia acquired at or after age 18 years. Primary outcome measures were resolution of diplopia in primary position and a deviation of 10 prism diopters or less in primary gaze. Additional clinical parameters were assessed.

RESULTS

Of 248 patients with adult-onset esotropia who underwent strabismus surgery, all experienced diplopia preoperatively except those with sensory esotropia. The four most common diagnoses were cranial nerve VI palsy in 36% (90 of 248), thyroid eye disease in 18% (45 of 248), age-related distance esotropia in 15% (38 of 248), and decompensated latent esodeviations in 13% (31 of 248) of patients. A variety of surgical procedures were employed, and adjustable sutures were used in 79% (196 of 248). Approximately 80% (158 of 197) of patients present at the 2-month postoperative follow-up visit were aligned within 10 prism diopters, and 72% (140 of 195) experienced resolution of diplopia. Success rates were significantly higher in patients with adjustable sutures. Reoperation rates were low overall at 15% (37 of 248) and were highest in cranial nerve VI palsies and lowest in age-related distance esotropia. Dose-response calculations showed a non-significantly smaller effect per millimeter of recession and resection in cranial nerve VI palsy and age-related distance esotropia.

CONCLUSIONS

The causes of adult-onset esotropia are diverse. A variety of surgical approaches are employed and, in conjunction with adjustable sutures, provide a good rate of diplopia resolution and acceptable ocular alignment. [J Pediatr Ophthalmol Strabismus. 2017;54(2):104-111.].

Factors associated with surgical success in adult patients with exotropia

PURPOSE

To report the results of surgical treatment for intermittent or constant comitant exotropia in adults and to examine the factors associated with the surgical outcome.

METHODS

The medical records of consecutive patients older than 18 years of age at the time of surgery for intermittent or constant comitant exotropia and with at least 1 year's follow-up were retrospectively reviewed. Surgical success was defined as postoperative esodeviation of <5^Δ, orthotropia, or exodeviation of <10^Δ. Overcorrection (defined as esodeviation >5^Δ) and recurrence (exodeviation of >10^Δ) were considered surgical failure. Preoperative patient characteristics, surgical procedures performed, and early postoperative ocular alignment were evaluated as potential factors associated with the surgical outcome.

RESULTS

A total of 39 patients were included, of whom 28 (72%) achieved surgical success, 7 (18%) showed overcorrection, and 4 (10%) had recurrence. Alignment at postoperative week 1 was the only significant factor correlated with surgical results. Surgical outcome was best with early postoperative alignment of <10^Δ of esotropia.

CONCLUSIONS

Early postoperative overcorrection of <10^Δ resulted in more favorable surgical outcomes in adults undergoing surgery to treat exotropia.

Contact topical anesthesia versus general anaesthesia in strabismus surgery

OBJECTIVE

To evaluate the anesthetic block provided by contact topical anesthesia (CTA) in strabismus surgery in adult patients. To analyze postoperative pain and surgical outcome obtained by CTA compared with general anesthesia (GA).

METHODOLOGY

Prospective longitudinal cohort study of adult patients undergoing strabismus surgery by CTA or GA. The intensity of pain perceived by patients during the course of surgery and in the postoperative period was measured using Numerical Pain Scale. The success of the surgical outcome, considered as a residual ocular deviation<10 prism diopters, was evaluated.

RESULTS

Twenty-three patients were operated using CTA and 26 using AG. During the course of surgery, pain intensity experienced by patients in ATC group was 3.17±2.44. There were no differences between CTA group and AG group in the intensity of pain in the immediate postoperative period (2.13±2.39 vs. 2.77±2.18, respectively; P=.510) and during the first postoperative day (3.22±2.84 vs. 3.17±2.73; P=.923). Surgical success was significantly higher in the CTA group than in the GA group (78.3 vs. 73.1%; P=.019).

CONCLUSIONS

CTA provides adequate sensory block to perform strabismus surgery. The control of postoperative pain is similar to that obtained with AG. Conservation of ocular motility providing CTA enables better surgical outcome.

Vision concerns after mild traumatic brain injury

OPINION STATEMENT

Mild traumatic brain injury (mTBI) can manifest with visual dysfunction including deficits in accommodation, vergence movements, versions, and field of vision as well increased photosensitivity and a decline in ocular and overall health. Patients with incomitant strabismus should be referred to an ophthalmologist for intervention. Patients with mTBI who experience photosensitivity, or deficits in accommodation, versions, vergences, or field of vision may benefit from vision rehabilitation. These therapies may include spectacles with tinting and a variety of prism combinations. Patients with chronic visual dysfunction following mTBI may benefit from occupational, vestibular, cognitive, and other forms of physical therapy.