Vertical Rectus Muscle Surgery Research Articles

A Comparative Study of Surgical Outcomes between the Adjustable Suture Technique and Conventional Technique in Strabismus Surgery

Objective: To compare the success rate between adjustable suture technique and conventional technique in rectus muscle surgery. Materials and Methods: The present study was a retrospective review of patients aged 10 and above underwent rectus muscle surgery between 2010 and 2018. Patients were classified into two groups according to the surgical techniques, the adjustable group and the conventional group. Preoperative and postoperative orthoptic evaluation including angle of deviation, sensory outcomes, and reoperation rate were collected. The primary outcome was surgical success rate at two years postoperatively, with success defined as ocular alignment within 10 prism diopters (PD) for horizontal rectus muscle surgery or within 5 PD for vertical rectus muscle surgery. The secondary outcome was reoperation rate and binocular functions improvement two years post-operation. Results: One hundred fifteen cases in the adjustable group and 90 in the conventional group were identified. Patients in the adjustable group had a higher success rate achieving the target angle after six months, one year, and two years post-operation compared to the conventional group at 77.4% versus 70% (p=0.23), 73.9% versus 65.6% (p=0.19), and 72.2% versus 60% (p=0.066), respectively, but there was no statistically significant difference. Sensory improvement was seen in 43.4% of patients in the conventional group and 42.6% in the adjustable group (p=0.54). Median stereopsis improvement was seen in both groups at 80 to 45 seconds of arc in the adjustable group and 100 to 60 seconds of arc in the conventional group (p=0.67). The reoperation rate was 18.9% in the conventional group and 19.1% in the adjustable group (p=0.97). Conclusion: The adjustable suture technique presented a superior success rate compared to conventional technique though there was no statistically significant difference. A longer follow-up period and larger sample size might be needed to demonstrate statistically significant difference between the two techniques. No significant difference in binocular functions, sensory improvement, or reoperation rate was seen in the present study. Keywords: Strabismus surgery; Adjustable suture; Conventional suture; Surgical outcome

Strabismus Surgery in Orthophoric Patients With Symptomatic, Asymmetric Vertical or Horizontal Incomitance

To report the indications, operative strategies, and surgical outcomes of patients who undergo vertical and horizontal rectus muscle surgery for incomitant strabismus despite being orthophoric in primary gaze. Retrospective, interventional case series. The setting for this study was an academic practice at Boston Children's Hospital. The patient population comprised 8 orthophoric patients who underwent strabismus surgery to treat vertical/horizontal incomitance. Observation procedures included review of surgical strategies, strabismus measurements in diagnostic gaze positions, and development of postoperative diplopia. The main outcome measures were preserved single vision in primary gaze, comitance, reoperation rate, and patient/surgeon satisfaction. Surgical strategies included the following: (1) simultaneous recession of ipsilateral antagonist rectus muscles; (2) recession or resection of 1 rectus muscle with balancing surgery on the fellow eye; (3) restricting the range of 1 muscle (combined resection and recession or posterior fixation suture); and (4) creating an acceptable deviation in primary gaze. Mean follow-up was 5.4 months (median, 2 months; range, 2-25 months). No patient had new-onset primary gaze diplopia. The median incomitance improved by 9.5 prism diopters. No patient required additional surgery. Patient satisfaction and surgeon assessment of outcomes were high. Although the risk of operating on orthophoric patients with incomitant strabismus may discourage surgeons from offering treatment, the use of specific strategies to address incomitance can preserve alignment in primary gaze while improving patient satisfaction. These strategies may also benefit patients with incomitant strabismus that is symptomatic in primary gaze.

Torsional strabismus and vertical rectus muscle surgery in thyroid eye disease

To assess the torsional component in patients with vertical strabismus due to thyroid eye disease (TED) and its course after vertical rectus muscle surgery. Retrospective chart review of patients undergoing vertical strabismus surgery for TED between 1998 and 2017, having undergone pre- and postoperative Harms tangent screen examination. Forty patients (27 women) were identified. A torsional component was present in all patients. Thirty-three patients had a mean excyclotorsion of 4.5° in primary position, increasing to 8.2° in upgaze, associated with restricted elevation. Inferior rectus muscle recession (n=29) reduced the excyclotorsion in all cases. A 4.4° mean incyclotorsion was present in primary position in 7 cases, increasing to 7.1° in downgaze. Superior rectus muscle recession reduced the incyclotorsion in 5/6 cases. The torsional surgical dose-effect relationship was correlated with the amount of preoperative torsion. The field of binocular single vision improved from 6.5% preoperatively to 71.1% after surgery. Ocular torsion is common in vertical strabismus secondary to TED and is significantly improved by vertical rectus muscle surgery alone. Surgery should be planned according to vertical deviation and motility limitation, and vertical rectus muscles surgery should be considered the first line of treatment, with selective oblique muscle surgery as a second-line option, which was unnecessary in our series.

Некоторые осложнения хирургии косоглазия

Surgical treatment of strabismus is aimed at achieving a cosmetic effect and restoring the operation of the binocular apparatus. But this type of treatment can lead to complications ranging from mild and self-limiting to severe, causing loss of vision. The purpose of our work is to present literature data on some complications of strabismus surgery, their clinical signs, methods of treatment and preventive measures. The material for writing the article was foreign publications from the international citation database Pubmed, which contained the keywords «strabismus», «strabismus surgery», «strabismus surgery complication». For the review, 27 articles were selected that meet the purpose of our work. The analysis of literature sources showed that the complications of strabismus surgery are diverse and include changes in the conjunctiva (damage to the plica semilunaris, chemosis, pyogenic granuloma, extruded of the Tenon's fascia, conjunctival cyst), impaired blood supply (anterior segment ischemia), scleral perforation, postoperative infection (endophthalmitis, subconjunctival abscess), the loss rectus muscle, fat adherense syndrome, eyelid retraction and ptosis following vertical rectus muscle surgery. Despite the rare occurrence, the listed complications can be the cause of functional or cosmetic changes. Keywords: strabismus, strabismus surgery, complication, oculomotor muscles

Effect of Vertical Transposition of the Horizontal Muscles on Vertical Strabismus Associated with Exotropia

Purpose: To evaluate the correction of vertical strabismus associated with exotropia by vertical transposition of the horizontal muscle to an extent equal to half the muscle width combined with muscle recession-resection. Methods: We enrolled patients with vertical strabismus of 4-15 prism diopters (PD) associated with exotropia who were not scheduled for vertical rectus or oblique muscle surgery. Regardless of the strabismus angle, the insertion site of the horizontal muscle was vertically transposed by half the muscle width during surgery. Success was defined as a vertical strabismus angle of 2 PD or less. Results: The preoperative mean exodeviation far angle in 41 patients was 27.8 PD and the average vertical strabismus far angle 8.1 PD. The success rate of exotropia surgery was 68.3%. The mean vertical strabismus angle was 2.8 PD on postoperative day 1 and the success rate of vertical strabismus surgery 92.7%. Undercorrection was evident in 4.9% of patients and overcorrection in 2.4%. The preoperative vertical strabismus angle was strongly associated with the residual angle after surgery (r = 0.386, <i>p</i> = 0.013). Receiver operating curve analysis revealed that the preoperative vertical strabismus far angle cutoff was 11 PDs. No patient factor significantly influenced vertical strabismus correction. Conclusions: Vertical transposition of the horizontal muscle by half of the muscle width may correct vertical strabismus of far angle 11 PDs or less.

Tendon elongation with bovine pericardium in strabismus surgery\u2014indications beyond Graves\u2019 orbitopathy

BackgroundFor some patients with complex ocular motility disorders, conventional strabismus surgery is insufficient. Surgery with tendon elongation allows correction of larger angles and maintains a sufficient arc of contact for rectus muscles. This study reports results for tendon elongation with bovine pericardium (Tutopatch®) in indications other than Graves’ orbitopathy in which it is already widely used.MethodsWe reviewed the records of all patients who underwent surgery with Tutopatch® in our institution. Angles of squint and head postures were analyzed preoperatively, on the first postoperative day, and in the long term (median 9 weeks after the operation). Patients with Graves’ orbitopathy were excluded.ResultsFrom 2011 to 2018, the procedures on 58 eyes of 54 patients (35 females, median age 35 years (3–75)) met the inclusion criteria. Horizontal rectus muscle surgery (53 eyes) was conducted on patients with residual strabismus (13), Duane’s retraction syndrome with eso- (type I: 16)/exodeviation (type II: 2, type III: 1), 6th (7)/3rd nerve palsy (7), Möbius syndrome (2), congenital fibrosis of the extraocular muscles type 3A (CFEOM3A, TUBB3 mutation) (4), and orbital apex syndrome (1). Vertical rectus muscle surgery (5 eyes) was conducted on patients with myasthenia (1), vertical tropia after orbital floor fracture (1), CFEOM1 (2), and Parry-Romberg syndrome (1). 42 eyes had prior eye muscle surgery (1–5 procedures, median 1). Out of 45 patients with postoperative long-term data, 43 showed an angle reduction. Fifty-one percent had an angle of 10Δ (prism diopter) or less, one had a significant over-effect, and 10 had revision surgery. For the heterogeneous group of residual eso- and exotropias, the median absolute horizontal angle was reduced from 35Δ (16 to 45Δ) to 9Δ (0 to 40Δ), for Duane’s retraction syndrome from 27.5Δ (9 to 40Δ) to 7Δ (0 to 40Δ), and for sixth and third nerve palsies from 43Δ (20 to 75Δ) to 18Δ (4 to 40Δ). For 3 patients with vertical rectus muscle surgery, the median absolute vertical angle was reduced from 30Δ (20 to 45Δ) to 4Δ (1 to 22Δ). The motility range was shifted in the direction contrary to the elongated muscle in all subgroups. A considerable reduction of the excursion into the field of action of the elongated muscle had to be registered.ConclusionsStrabismus surgery with bovine pericardium introduces new surgical options for complicated revisions and for rare and complex oculomotor dysfunctions. Yet, it has to be recognized that this type of surgery aiming at maximum effects, despite preservation or restitution of the arc of contact, leads to reduction of the excursion into the field of action of the elongated muscle. Furthermore, dose finding can be difficult depending on the underlying pathology and more than one intervention might be necessary for optimal results.

Immediate Postoperative Alignment Measurements as a Predictor of Alignment Stability in Fixed Suture Strabismus Surgery.

To evaluate the use of immediate postoperative alignment measurements as a predictor of future alignment stability in fixed suture strabismus surgery. Forty-seven patients were prospectively evaluated after undergoing horizontal or vertical rectus muscle surgery using a fixed suture technique. Alignment measurements were taken approximately 1 hour, 1 to 3 weeks, and 2 to 3 months postoperatively. A Spearman correlation coefficient was used to compare measurements from the immediate postoperative period to the 2- to 3-month postoperative period. Patients with dissociated strabismus, only oblique muscle surgery, or poor vision in one or both eyes precluding precise alternate cover test were excluded. Mean age of all patients was 46.7 years (range: 12 to 86 years). Twenty-two patients underwent surgery for exotropia: 19 for esotropia and 6 for hypertropia. Mean alignment for all surgeries was 2 prism diopters (PD) undercorrection in the immediate postoperative period, which was similar to the mean of 4.6 PD undercorrection at 2 to 3 months postoperatively. However, the Spearman correlation between the immediate postoperative and 2- to 3-month postoperative measurements was 0.18 for all surgeries, 0.03 for exotropia, 0.56 for esotropia, and 0.40 for hypertropia. The overall success rate, defined as 8 PD or less of horizontal deviation and 4 PD or less of vertical deviation, was 77% at 2 to 3 months postoperatively. The relationship between immediate postoperative alignment and future alignment stability in fixed suture strabismus surgery has not been previously defined. The current study demonstrated that although the surgical success rate was reasonably good, poor correlation occurred between the alignment immediately postoperatively and 2 to 3 months postoperatively. [J Pediatr Ophthalmol Strabismus. 2018;55(4):240-244.].

Efficacy of Vertical Muscle Transpositions with and without Simultaneous Rectus Muscle Recession for Unilateral Sixth Nerve Palsy

We report results of a modified vertical muscle transposition procedure according to the Hummelsheim principle - with and without simultaneous rectus muscle recession - for unilateral sixth nerve palsy. We examine the influence of the duration of the palsy, preoperative angle of squint and preoperative abductive capacity on surgical results of the procedures. Retrospective study of 29 consecutive patients with unilateral abducens nerve palsy who underwent surgery between 2001 and 2012. 21 patients had a modified vertical rectus muscle transposition according to the Hummelsheim principle (HUM); 8 patients had this operation combined with simultaneous medial rectus muscle recession (HUM+I). Surgery was performed at least 9 months after onset of the palsy (HUM: 9 to 98, median 19, mean 30months; HUM+I: 12 to 65, median 25, mean 29 months). The median preoperative angle of squint (far distance) for the HUM group was 27.0° (20.0 to 45.0; mean 28.1°), and for the HUM+I group 30.5° (21.8 to 50.0; mean 33.4°). The median preoperative abductive capacity was for - 1,6 mm before midline (- 8.0 to + 1.2; mean - 1.8 mm) for the HUM group, and - 3.0 mm before midline (- 10.0 to - 1.0; mean - 4.1 mm) for the HUM+I group. The median postoperative angle of squint (far distance) was 0° (- 11.3 to + 20.0; mean 0.1°) for the HUM group, and - 2.3° (- 11.3 to + 12.0; mean - 2.1°) for the HUM+I group. The median postoperative abductive capacity was 1.0 mm (0 to + 3.0; mean + 1.1 mm) for the HUM group, and 1.1 mm (- 1.2 to + 3.0; mean + 0.9 mm) for the HUM+I group. The median reduction of squint angle was 27.0° (9.1 to 45.0; mean 28.0°) for the HUM group, and 36.8° (25.2 to 41.4; mean 35.5°) for the HUM+I group. The median effect on abductive capacity was 2.5 mm (0 to 11.0; mean + 2.9 mm) for the HUM group, and 4.6 mm (2.4 to 8.8; mean + 5.0 mm) for the HUM+I group. In the HUM group, the effect on squint angle reduced with the duration of the palsy, whereas, in the HUM+I group, the effect improved with the duration of the palsy. For patients with unilateral sixth nerve palsy, simultaneous medial rectus recession increases the effect of modified vertical rectus muscle surgery according to the Hummelsheim principle. The duration of the palsy is a relevant parameter for the selection of a sole or combined intervention with medial rectus recession.

Immediate postoperative alignment measurements as a predictor of alignment stability in fixed suture strabismus surgery

Purpose To evaluate the use of immediate postoperative alignment measurements as a predictor of future alignment stability in fixed suture strabismus surgery. Methods Forty-seven patients were prospectively evaluated after undergoing horizontal or vertical rectus muscle surgery using a fixed suture technique. Alignment measurements were taken approximately 1 hour, 1 to 3 weeks, and 2 to 3 months postoperatively. A Spearman correlation coefficient was used to compare measurements from the immediate postoperative period to the 2- to 3-month postoperative period. Patients with dissociated strabismus, only oblique muscle surgery, or poor vision in one or both eyes precluding precise alternate cover test were excluded. Results Mean age of all patients was 46.7 years (range: 12 to 86 years). Twenty-two patients underwent surgery for exotropia: 19 for esotropia and 6 for hypertropia. Mean alignment for all surgeries was 2 prism diopters (PD) undercorrection in the immediate postoperative period, which was similar to the mean of 4.6 PD undercorrection at 2 to 3 months postoperatively. However, the Spearman correlation between the immediate postoperative and 2- to 3-month postoperative measurements was 0.18 for all surgeries, 0.03 for exotropia, 0.56 for esotropia, and 0.40 for hypertropia. The overall success rate, defined as 8 PD or less of horizontal deviation and 4 PD or less of vertical deviation, was 77% at 2 to 3 months postoperatively. Conclusions The relationship between immediate postoperative alignment and future alignment stability in fixed suture strabismus surgery has not been previously defined. The current study demonstrated that although the surgical success rate was reasonably good, poor correlation occurred between the alignment immediately postoperatively and 2 to 3 months postoperatively. [J Pediatr Ophthalmol Strabismus. 2018;55(4):240-244.].

Correction of Hypertropia Coexisting with Intermittent Exotropia

Purpose: To investigate the clinical features associated with hypertropia and report the surgical outcomes of hypertropia coexisting with exotropia. Methods: We reviewed the medical records of 148 patients with intermittent exotropia coexisting with hypertropia over 4 PD who received exotropia surgery. The cases accompanied by apparent paralytic strabismus such as superior oblique palsy were excluded. Patients were divided into groupI(clinically diagnosed hypertropia) and group II (non-specific hypertropia) and the clinical features of coexisting hypertropia and surgical outcomes were analyzed. Results: Among the 148 patients, groupIconsisted of 38 patients (26%) and group II of 110 patients (74%). The average amount of preoperative hypertropia angle in primary gaze was 9.58 ± 3.89 PD and 6.62 ± 2.69 PD in group I and II, respectively. Group I included 12 patients with dissociated vertical deviation (DVD), 10 patients with unilateral inferior oblique overaction, 13 patients with asymmetric bilateral inferior oblique overaction and 3 patients with superior oblique overaction. Group II included 19 patients with comitant hypertropia (17%), head tilt positive pattern (simulated superior oblique palsy) was found in 84 patients (76.3%) and variable incomitance was observed. In groupI, 29 patients received simultaneous horizontal muscle with hypertropia surgery. Postoperative hypertropia angle in groupI was 1.41 ± 2.93 PD and 4 cases were considered surgical failure. In groupII, hypertropia was resolved with horizontal muscle surgery only and the amount of postoperative hypertropia was 0.45 ± 1.60 PD. Conclusions: In this study, vertical deviations in intermittent exotropia with concomitant hypertropia related to obvious oblique muscle dysfunction or DVD were corrected effectively by oblique or vertical rectus muscle surgery. Nonspecific hypertropia can be resolved after horizontal muscle surgery alone, however, for precise differential diagnosis, careful examination for variable clinical features is necessary before determining surgery. J Korean Ophthalmol Soc 2014;55(12):1883-1889

Localising rectus muscle insertions using high frequency wide-field ultrasound biomicroscopy

AimThe ultrasound biomicroscope (UBM) can accurately locate an extraocular muscle (EOM) insertion. The authors compared the accuracy of the Sonomed UBM (SUBM), a new ‘wide-field ultrasound biomicroscope’, with the older...

Surgical management of clinically significant hypertropia associated with exotropia

To report the surgical treatment of hypertropia coexisting with exotropia, with either vertical offset surgery or additional vertical muscle surgery simultaneous to correction of the exotropia. A total of 35 patients with exotropia and hypertropia who underwent a horizontal muscle surgery for exotropia were included. To determine efficacy in resolving a vertical deviation in patients with exotropia, 28 patients were compared in 2 groups: those who underwent horizontal muscle surgery with vertical offset and those who underwent horizontal muscle surgery with additional vertical muscle surgery. An additional 7 patients who had exotropia and hypertropia but did not undergo vertically corrective surgery were included for comparison. Vertical offset of horizontal rectus muscles (4 mm) resulted in 8(Delta) correction of the distance hypertropia. Vertical rectus muscle recession used in the treatment of larger hypertropic deviations with exotropia had a 3(Delta) correction per 1 mm of recession. Success rates for hypertropia correction were similar between groups, 63% vertical offset and 71% vertical muscle groups; overcorrections occurred in 29% of the vertical muscle group. The vertical correction in both groups was stable in 88% over 6 months postoperatively. Vertical offset of the horizontal muscles simultaneous with exotropia correction has a beneficial effect in small-angle hypertropia (<14(Delta)). Vertical rectus muscle surgery in patients with hypertropia greater than 10(Delta) had equivalent success; however, in intermittent exotropia the hypertropia was prone to overcorrection.

021: Surgical management of clinically significant hypertropia associated with exotropia

Introduction: Vertical muscle deviations often coexist with basic horizontal muscle deviations. Previous studies have focused on separate horizontal rectus and vertical rectus muscle surgery (deviations >15Δ) or horizontal muscle transposition surgery alone to effectively resolve a vertical deviation. The purpose of this study is to determine whether horizontal muscle surgery with transposition or additional vertical muscle surgery is most effective in resolving a vertical deviation in patients with exotropia. Additionally, to determine the measurement for incorporating a vertical muscle surgery to an exotropic surgery improve its overall effect.

Combined Eyelid and Strabismus Surgery: Examining Conventional Surgical Wisdom

To determine whether satisfactory results of both eyelid surgery and strabismus surgery can be obtained when these procedures are performed in the same setting in selected patients. Nine patients (16 eyelids) who had undergone surgery in the same setting for eyelid malposition and strabismus of the horizontal rectus muscles, with or without concurrent vertical rectus muscle surgery, were retrospectively reviewed. Eyelid malposition surgery success was defined as a postoperative margin reflex distance (MRD1) within 1 mm of the target. Strabismus surgery success was defined as a postoperative deviation within 8 prism diopters of orthophoria or a decrease in binocular diplopia if the patient had a less than 8 prism diopters deviation in primary gaze preoperatively. Eyelid retraction repair was performed on 13 upper eyelids, levator advancement was performed on 2 eyelids, and frontalis suspension was performed on 1 eyelid. Four patients underwent bilateral medial rectus recession and the remaining 5 patients received varying strabismus surgery. Four patients received adjustable sutures. Mean follow-up was 11 months. Postoperatively, 13 of 16 eyelids (81%) achieved an MRD1 within 1 mm of the target. Eight of 9 patients (89%) demonstrated satisfactory strabismus correction. Combined eyelid malposition and strabismus surgery can be successfully performed in selected cases, particularly when the strabismus surgery involves the horizontal rectus muscles. Combined surgery is not recommended in cases that do not involve the horizontal rectus muscles.

Vertical rectus muscle surgery for nystagmus patients with vertical abnormal head posture

Purpose To characterize the results of vertical rectus muscle recession, or recession and resection surgery for vertical abnormal head posture (VAHP) due to null-point nystagmus. Method This is a retrospective, noncomparative, consecutive case series of patients who underwent vertical rectus muscle recession alone, recession then resection, or combined recession/resection surgery for VAHP due to null-point nystagmus. The primary outcome measure was the amount of residual VAHP. Results Twenty patients with VAHP due to null-point nystagmus were studied. The mean follow-up interval after surgery was 49 months (median: 44 months; range 9 to 124 months). Preoperative VAHP ranged from 10° to 45°, and the total amount of bilateral vertical rectus muscle recession, or recession and resection surgery, ranged from 8.5 to 20.0 mm per eye. After recession alone, 5/11 had residual VAHP ≤ 5°. The remaining six underwent subsequent resection or plication for residual VAHP > 10° that resulted in residual VAHP ≤ 5° in each case. After combined recession/resection, 6/9 had residual VAHP ≤ 5° and the remaining three had VAHP < 10°. Conclusion Large amounts of vertical rectus muscle surgery are indicated to successfully correct the VAHP associated with nystagmus with a vertical null point. Combined recession/resection of the appropriate vertical rectus muscles, instead of recession alone, appears to be a more effective procedure.

Early reoperation after vertical rectus muscle surgery

Purpose: Adjustable suture strabismus surgery has a success rate between 90% and 94%. In some patients, undesirable deviations are noted in the first week after surgery. In this article, we describe a method of reoperation in the first week of the initial repair in an outpatient clinical setting. Methods: A retrospective review of clinical records from 1990 to 1998 identified 7 patients who underwent reoperation of the original surgical procedure in a clinic setting. All patients had vertical deviations that were overcorrected and had a reversal of their diplopia. Results: Follow-up ranged from 3 months to 59 months. All patients were free of diplopia and were either orthophoric or had small phoric deviations. Conclusions: Proper identification of patients with strabismus as a result of overcorrected adjustable sutures and prompt reoperation in the first week after surgery are possible and prevent the need for repeat anesthesia in the operating suite. (J AAPOS 2001;5:217-20)

Anterior transposition of the superior oblique tendon in the treatment of oculomotor nerve palsy and its influence on postoperative hypertropia.

To determine whether postoperative hypertropia after anterior transposition of the superior oblique tendon without trochleotomy could be avoided with a simplified surgical approach. Eight patients with oculomotor nerve palsy (one patient was bilaterally affected) were retrospectively identified as having undergone anterior transposition of the superior oblique tendon without trochleotomy or vertical rectus muscle surgery between March 1992 and September 1998. The superior oblique tendon was cut at the medial border of the superior rectus muscle and placed 1-3.5 mm anterior to the medial insertion of the superior rectus muscle in each of these patients. Resection of the superior oblique tendon was not performed. The lateral rectus muscle was weakened, and no vertical rectus muscles were resected. Preoperative deviations with the uninvolved eye fixating in primary position ranged from 20-90 prism diopters (delta) of exotropia (mean: 49.3 delta) and from 0-20 delta of hypotropia (mean: 11.25 delta). Postoperative horizontal deviations in the primary gaze position ranged from 12 delta of exotropia to 20 delta of esotropia. Six cases were aligned within 10 delta of exotropia or esotropia. Postoperative vertical deviations in the primary gaze position ranged from 2 delta of hypertropia to 8 delta of hypotropia. Six cases were aligned within 2 delta of deviation. Significant postoperative restrictive hypertropia, or new postoperative paradoxical ocular movements, did not occur in any patient. Patients who underwent follow-up >4 months maintained stable eye alignment. Transposition of the superior oblique tendon without simultaneous resection or trochleotomy, or additional surgery to the vertical rectus muscle simplifies the surgical technique and eliminates subjective decision making regarding the amount of resection.

Changes in eyelid position accompanying vertical rectus muscle surgery and prevention of lower lid retraction with adjustable surgery.

Whether or not eyelid position changes are caused by vertical rectus muscle surgery is controversial and poorly understood. We reviewed pre- and postoperative photographs of patients who underwent recession or resection of one or more vertical rectus muscles in a 10-year period. A change in eyelid position occurred frequently with vertical rectus muscle surgery. With superior rectus recession, 91% of the patients developed upper lid retraction. With inferior rectus recession, 94% of patients developed lower lid retraction. With inferior rectus resection, every patient developed lower lid advancement with accompanying flattening. We describe an adjustable surgical technique to prevent lower lid retraction associated with inferior rectus recession. The technique involves a separate adjustable suspension of the lower eyelid retractors from the inferior rectus insertion at the time of strabismus surgery. The lid position can then be adjusted separately at the time of muscle adjustment. After an average 2 1/2-month follow up, no statistically significant lid retraction could be measured in six patients who underwent the adjustable lid suspension, while statistically significant retraction (P < .01) developed in a group of nine patients who had inferior rectus recession alone. This technique did not limit the success of the strabismus surgery.

Recovery of Anterior Segment Circulation after Strabismus Surgery in Adult Patients

The effects of vertical rectus muscle surgery on the anterior segment and iris fluorescein angiogram were documented in 43 eyes of 41 adult patients. Characteristic iris sector perfusion defects were seen in 33 of 37 eyes (89%) after primary vertical rectus muscle surgery (no previous surgery on these muscles). Although iris perfusion defects were commonly present, associated clinical signs were mild. Two patients developed permanent pupillary changes after simultaneous surgery on two rectus muscles (superior/inferior rectus muscles and contiguous inferior/medial rectus muscles). In most patients, clinical findings resolved and the iris circulation recovered during the first 2 weeks after surgery. In 3 of 8 patients with grade 3 anterior segment ischemia (pupil dysfunction and cells) or early "postoperative uveitis," recovery of iris circulation took up to 12 weeks. These findings indicate that the time course of recovery of the anterior segment circulation after vertical rectus muscle surgery may be shorter than previously assumed.

The effects of strabismus surgery on anterior segment circulation.

Anterior segment circulation was assessed in 35 adults one day after squint surgery by clinical observation and low-dose fluorescein iris angiography. Seventeen patients had primary vertical rectus muscle surgery and all showed angiographic evidence of ischaemia. No ischaemia was found in the 15 patients who had secondary vertical rectus muscle surgery, or any horizontal rectus muscle surgery. The staged group had intermediate findings between the above two. Age, dysthyroid eye disease and type of conjunctival incision did not correlate with fluorescein iris angiographic sector-filling delay on the first post-operative day. The time taken for the sector with delay to fill becomes less during the first two post-operative weeks. Redistribution of iris filling persists, however. This data suggest that the safe interval before further muscle surgery can be done is shorter than has previously been assumed. Since the anterior ciliary arteries do not reform into canals the probable mechanism of redistribution of blood flow is from the long posterior ciliary arteries and increased capacity of the collateral circulation.