Horizontal Rectus Muscle Recession Research Articles

Novel superior oblique anterior fiber plication with or without adjustable sliding knot for extorsion

PurposeTo report a novel surgical technique to correct excyclotropia, consisting of a superior oblique anterior fibers plication (SOAFP) with or without a hemihangback anterior knot, allowing access for postoperative adjustment. MethodsA retrospective interventional case series was conducted. Fourteen patients, 21-92 years of age, underwent SOAFP (18 eyes, 14 eyes on adjustable), at the Mayo Clinic in Rochester, Minnesota. SOAFP was the only procedure performed in 12 eyes; in 6 it was performed in conjunction with up to four horizontal rectus muscle recession, resection, and/or plication. Ocular alignment was assessed with prism and alternate cover and double Maddox rod tests; preoperatively, at initial and final (closest to 6-8 weeks) postoperative visits. ResultsPreoperative torsion ranged from 2° to 30° of extorsion (mean, 10.14 ± 7.01). A SOAFP of 2–30 mm (mean, 8.93 ± 5.63) was performed. At the initial postoperative examination, mean intorsional shift was 11.18 ± 7.37, accounting for 1.86° ± 1.04° of correction per millimeter of plication. Three eyes were adjusted after the initial visit to obtain a stronger plication effect targeting of 5° intorsion. At the final visit, 61 ± 23 days postoperatively, mean extorsion was 1.21° ± 2.29°, ranging from 5° of extorsion to 3 of intorsion. Mean final intorsional shift was 9.14 ± 7.53°, accounting for a 1.16 ± 0.50° of correction per millimeter of plication. Of our 14 patients, 13 had improvement in diplopia. ConclusionsIn our study cohort, SOAFP allowed for targeted and easily adjustable correction of extorsion.

Assessment of retinal and choroidal microcirculation after unilateral recession–resection surgery for horizontal strabismus by swept-source optical coherence tomography angiography

This study explored the possible hemodynamic changes of the retina and choroid after horizontal strabismus surgery using swept-source optical coherence tomography angiography (SS-OCTA). 32 eyes of 32 patients who underwent unilateral horizontal rectus muscle recession–resection surgery were included. SS-OCTA examinations were performed preoperatively and one week postoperatively. Several OCTA measurements were used, including vessel density (VD) of the superficial vascular complex (SVC), VD of the deep vascular complex (DVC), VD of the choriocapillaris (CC), choroidal vascular index (CVI) and choroidal thickness (CT). No significant change in VD of SVC, DVC, and CC was observed whereas CT increased significantly with CVI unchanged. Recession–resection surgery for horizontal strabismus seemed not to significantly influence the microcirculation of the retina and CC in the early postoperative period. However, choroidal thickening happened with a constant CVI probably due to the postoperative inflammation. Further studies are needed to investigate the long-term effects of unilateral recession–resection surgery for horizontal strabismus on the microcirculation of the retina and choroid.

Evaluation of Macular Thickness Changes Following Large Horizontal Rectus Muscle Recession: A Prospective Cohort Study.

Aim The aim of the study was to evaluate the long-termeffect of large horizontal rectus muscle recession on macula thickness using spectral domain optical coherence tomography (SD-OCT). Material and methods Forty-twochildren were included in the study. The intervention groups were the medial rectus (MR) group (=20 eyes ) and the lateral rectus (LR) group (=22 eyes), including the eyes that underwent large medial and lateral rectus muscle recession, respectively. The control group included the fellow 42 unoperated eyes of the same children. Each eye was scanned using Topcon Maestro2 OCT-Angiography (OCTA; Topcon, Tokyo, Japan) preoperatively and then two months following surgery. A paired t-test was used to compare the mean difference in macular thickness between the intervention and control groups using the statistical program R (R Foundation for Statistical Computing, Vienna, Austria). Results The mean change in central, parafoveal, and perifoveal macular thickness of the intervention group was not statistically significant. Conclusion The long-term changes in macular thickness, as evaluated using SD-OCT both for the central and peripheral regions of the fovea, following large horizontal rectus muscle recession surgery, are not statistically significant.

Palpebral fissure changes following horizontal recti muscles surgery

Background Strabismus surgery is a 1-day operation. It can result in aligned eyes or nearly so (orthophoria) or overcorrection or undercorrection that may require further treatment or another surgery. Aim To assess alterations in vertical palpebral fissure height following horizontal recti muscle surgery (recession or resection) for the treatment of horizontal strabismus (esotropia or exotropia). Patients and methods A prospective interventional case series was carried out on 68 eyes of 41 patients with horizontal strabismus (exotropia or esotropia), comitant or incomitant (paralytic), who underwent surgical correction. Patients were subdivided into three groups: group I (n=50) underwent recession only, group II (n=10) underwent resection only, and group III (n=8) underwent recession and resection. All patients were subjected to preoperative, operative, and postoperative evaluations (palpebral fissure height and width measurement). Results Distant angle of exotropia was considerably lower in group I than group III (P2<0.019) but were insignificantly different between groups I and II and between groups II and III. Palpebral fissure at 6 months was considerably lower in group II than groups I and III (P=0.013 and 0.019, respectively). Conclusion Horizontal rectus muscles recession for horizontal strabismus causes vertical widening of palpebral fissure height, and also resection results in narrowing of vertical palpebral fissure height. The combination of horizontal rectus muscle recession and resection for horizontal strabismus results in vertical palpebral fissure height widening in half of eyes and vertical palpebral fissure height narrowing in a quarter of the eyes.

Unilateral Horizontal Rectus Muscle Recessions for Pediatric Comitant Strabismus

ABSTRACT Introduction Compared to bilateral horizontal rectus muscle recessions (BHR), a unilateral horizontal rectus muscle recession (UHR) confers shorter operating time and anesthesia exposure, limits complication risks to one eye, and requires less recovery from the patient. Methods Retrospective chart review of pediatric patients who underwent unilateral medial rectus recession (UMR) for esotropia (ET), or unilateral lateral rectus recession (ULR) for exotropia (XT). Primary successes were defined as maximum distance deviation at post-operative month 3: −12 to +5 for ET, −5 to +12 for XT. Rates of postoperative horizontal incomitance (HI) >5 PD and success for small medium, and large (in mm, respectively, ET: <5, 5–6 mm, >6; XT: <8, 8–10, >10) recessions were analyzed. Results Seventeen ETs and 40 XTs were analyzed. Overall primary success was 71.9% (p = .02). Significantly, 80% (95% CI: 67.60,92.40) XTs succeeded. ETs were equally likely to succeed (53.9%) or fail (47.1%) (p = .22). For patients without significant preoperative HI, average postoperative HI was 3.90 PD (95% CI: 0.20, 7.60) for ETs; 5.48 PD (95% CI: 3.65, 7.32) for XTs. Conclusions UHR was 71.9% successful in treating pediatric comitant strabismus. ULR for XT, particularly small to medium deviations, was most likely to succeed. In contrast to prior reports, large UMR and ULR were less likely to succeed and post-operative incomitance was frequent but rarely clinically significant.

Long-term astigmatism changes following horizontal muscle recession: a prospective cohort study

ABSTRACT Strabismus surgery may cause refractive changes, particularly in astigmatism. The aim of this study is to evaluate those changes in astigmatism two and 12 months following unilateral recession of horizontal rectus muscles in children. The authors prospectively evaluated 66 children with esotropia or exotropia, that would undergo a unilateral recession strabismus surgery. Comparisons were made between the 66 eyes that would undergo strabismus surgery and the fellow unoperated 66 eyes of the same children. The 66 eyes that would undergo strabismus surgery were divided into medial (38 eyes) and lateral (28 eyes) rectus muscle subgroups, and further, into subgroups based on the astigmatism axis preoperatively (with-the-rule astigmatism: 35 eyes, no astigmatism: 20 eyes, oblique astigmatism: 10 eyes, against-the-rule astigmatism: 1 eye). All patients were examined one day preoperatively, and then, two and 12 months postoperatively. Paired tests were conducted, and the significant level was set to 0.05 or was adjusted for subgroups. Mean age of children included was 6.73 years (SD = 3.19). Mean astigmatism values preoperatively, 2 and 12 months postoperatively were 0.92D (SD = 0.95), 1.45D (SD = 1.04) and 1.50D (SD = 1.10), respectively, for the eyes that underwent strabismus surgery. A statistically significant mean increase of 0.58D in astigmatism values in the eyes that underwent strabismus surgery was observed 12 months postoperatively (p < .005). Astigmatism values in the eyes that did not undergo strabismus surgery did not statistically significantly change during the observation period. The increase of the absolute values of astigmatism in medial and lateral rectus muscle subgroups was similar, 0.59D (SD = 0.10) and 0.57D (SD = 0.11), respectively. For the eyes that had with-the-rule astigmatism and no astigmatism preoperatively, a statistically significant increase was shown 12 months postoperatively (0.64D and 0.66D respectively) (p < .005). Changes in astigmatism were observed in the eyes which underwent recession of horizontal rectus muscles compared to the fellow eyes, which did not undergo any intervention. An increase in cylindrical power was noted in the eyes that had with-the-rule and no astigmatism prior to surgery. This increase may be interpreted by the decreased tension of the recessed rectus muscle following strabismus surgery. Decreased forces, caused by the recessed horizontal rectus muscle, acting on the sclera on 180-degree meridian may lead to corneal flattening on this particular meridian and consequently, a corneal steepening on the 90-degree meridian. These changes seem to be stable during the first 12 postoperative months.

Changes in astigmatism after horizontal muscle recession strabismus surgery: A retrospective cohort study.

Purpose:The aim of this study was to evaluate the changes in astigmatism after unilateral recession of horizontal rectus muscles in pediatric patients.Methods:The authors retrospectively evaluated the medical history of 52 children with esotropia or exotropia, that underwent a unilateral recession strabismus surgery. The intervention group consisted of the 52 eyes that underwent strabismus surgery, and the control group consisted of the other 52 fellow unoperated eyes of the same participants. The intervention group was divided into medial and lateral rectus muscle subgroups, and four subgroups based on the astigmatism axis preoperatively (A: with-the-rule astigmatism, B: no astigmatism, C: intermediate meridians, D: against-the-rule astigmatism). All patients were examined one day preoperatively, and then, six weeks postoperatively. Paired tests were conducted, and the significant level was set to 0.05 or was adjusted for subgroups.Results:A mean difference 0.43 D of astigmatism (95% CI: 0.27, 0.59) was observed after the surgery between intervention and control group (P < 0.001). Astigmatism change (postoperative - preoperative) in subgroup A was 0.50 D (P < 0.001) and in subgroup B was 0.75 D (P < 0.001). Moreover, astigmatism changes of 0.50 D were found in both lateral (P < 0.001) and medial rectus muscle group (P = 0.002).Conclusion:Strabismus surgery appears to be associated with alterations in astigmatism, and in particular increase in cylindrical power in the eyes that had with-the-rule astigmatism or no astigmatism preoperatively. Those changes should be considered when planning the operation, to avoid transforming clinically non-significant astigmatism into clinically significant.

Changes of Corneal Topographic Measurements and Refractive Errors after Horizontal Muscle Surgery. A Case Series

Abstract Background: Refractive and corneal topographic changes after routine strabismus surgery have been reported and can occur even after a successful surgery. Study aims to evaluate the effect of horizontal muscle surgery on refractive errors and corneal measurements. Patients and methods: This study includes 25 eyes of 22 patients who have manifest strabismus. The patients were divided into two groups. Group A (10 eyes of 7 patients) subjected to unilateral lateral rectus recession. Group B (15 eyes of 15 patients) all of them subjected to lateral rectus recession and medial rectus resection in the same eye. Cycloplegic automated refraction (including spherical equivalent, astigmatic error and astigmatic axis) were recorded preoperatively, one month and 3 months after surgery. Corneal topography including flat K, steep K were recorded preoperatively, one month and 3 months after surgery. Results: A significant change of spherical equivalent towards myopic shift after horizontal rectus muscle recession was observed (P=0.000). A significant change of refractive cylindrical power with rule was found in both groups (P=0.000). Corneal topographic parameter (flat k) showed a significant change in the both groups (P=0.000). . These changes persisted till the last postoperative visit. Conclusion: Horizontal muscle surgery induced a statistically significant change of astigmatism power that persists till the 3rd. postoperative month. A significant change of spherical equivalent was found in the postoperative period after horizontal strabismus surgery only in recession group.

Vertical rectus muscle recession versus combined vertical and horizontal rectus muscle recession in patients with thyroid eye disease and hypotropia

To compare the postoperative vertical drift in patients with thyroid eye disease (TED) with hypotropia who underwent vertical rectus recession alone versus vertical rectus recession combined with horizontal rectus recession. The medical records of patients with TED who underwent strabismus surgery for hypotropia between 2006 and 2015 were reviewed retrospectively. Patients were divided into two groups: group 1 underwent vertical rectus recession only; group 2 underwent vertical rectus recession plus horizontal rectus recession. Data collection included pre- and postoperative deviation measurements and amount of surgical recession performed. The amount of postoperative vertical drift between groups was compared. Of 67 patients who underwent surgery during the study period, 18 met inclusion criteria, 9 in each group. Mean postoperative hypotropia was 24.2Δ in group 1 and 24.5Δ in group 2 (P=0.82). Mean vertical deviations were 0.3Δ and -2.2Δ (P=0.134) on postoperative day 1; -0.9Δ and -8.0Δ (P=0.043) at final follow-up for groups 1 and 2. Mean postoperative vertical drift toward hypertropia was 1.2Δ in group 1 and 6.8Δ in group 2 (P=0.048). The surgical success rate for group 1 was superior to that for group 2 (89% vs 67% [P=0.024]). There was a significantly larger postoperative vertical drift in TED patients with hypotropia who had combined vertical rectus and horizontal rectus recessions compared with those who underwent vertical rectus recession alone.

Case Series: Botulinum Toxin in the Management of Duane Retraction Syndrome type I

Introduction: Duane retraction syndrome (DRS) is a form of congenital strabismus related to impairment of extraocular muscle innervation. The condition was first described by Mr. Duane as absence or limitation of abduction with narrowing of palpebral fissure in adduction and globe retraction. DRS is thought to be caused primarily by agenesis of the sixth nerve nucleus, leading to fibrosis of the lateral rectus muscle. Horizontal rectus muscle recession is still considered the preferable surgical intervention. Indications include large deviation in primary position, abnormal head position or significant upshoot or downshoot. The rule of botox in DRS is still not fully understood. In this short series we aim to explore the efficacy of botulinum toxin as an alternative to surgical intervention in patients with DRS type 1. Cases: The series include four patients of DRS type 1. Three patients underwent botox injection as a primary mode of treatment and one patient had a history of strabismus surgery two years prior to botox injection. Two patients maintained orthophoria over a follow-up period of 24 months; one patient didn't benefit from botox injection with similar angle of deviation pre and post injection. The fourth patient with history of strabismus surgery responded with reduction of the angle of deviation in the first and second visits, with return to the pre-injection angle on the sixmonth follow-up visit. Conclusion: Botulinum toxin can serve as an alternative to surgery in DRS type I especially in young age groups where surgical intervention is not preferable. Further large-scale studies are needed to evaluate its use in other types of the syndrome and to explore its long-term effect.

Correlation between the axial length and the effect of recession of horizontal rectus muscles

Purpose The aim of this study is to determine whether the axial length (AxL) measurement would be useful in predicting the effect of horizontal rectus muscles recession. Patients and methods This study retrospectively reviewed 94 patients (52 with intermittent exotropia and 42 with infantile esotropia and partially accommodative esotropia), with age ranging from 4 to 15 years (7.63±3.2). All cases underwent bilateral lateral rectus recession for exotropia and bilateral medial recession for esotropia; there were no cases of combined vertical strabismus. There was no history of any ocular trauma or previous strabismus surgery. Preoperative angle of deviation, AxL (IOL Master), and postoperative angle of deviation at 6 months were recorded; effect of recession was calculated in all cases. Results The mean AxL for all cases was 23.39±1.73. The patients were divided into two groups: exotropia group (n=52) and esotropia group (n=42). Each group was subdivided into two subgroups: subgroup I (AxL<23.39) and subgroup II (AxL≥23.39). The effect of recession in exotropic group was 2.27±0.29; in short AxL subgroup, it was 2.42±0.17, and in long AxL subgroup, it was 1.98±0.25. In esotropic group, the effect of recession was 3.36±0.53; in subgroup I, it was 3.67±0.31, and in subgroup II, it was 2.87±0.44. Conclusion The results showed a negative correlation between AxL and effect of recession in both esotropia and exotropia groups. It is recommended to increase the amount of recession in longer AxL.

Comparison of postoperative vertical drift in patients with thyroid eye disease with hypotropia: Vertical rectus muscle recession vs combined horizontal rectus muscle recession

Comparison of postoperative vertical drift in patients with thyroid eye disease with hypotropia: Vertical rectus muscle recession vs combined horizontal rectus muscle recession

A prospective evaluation of retroequatorial recession of horizontal rectus muscles and Hertle-Dell'Osso tenotomy procedure in patients with infantile nystagmus with no definite null position

To compare results of retroequatorial recession of horizontal rectus muscles and Hertle-Dell'Osso tenotomy procedure in patients with infantile nystagmus with null in primary position. In this prospective study, 10 subjects ≥5years of age with infantile nystagmus with null in primary position were randomly assigned to two groups: group 1 underwent a large retroequatorial recession of the four horizontal rectus muscles; group 2, simple tenotomy and resuturing (Hertle-Dell'Osso procedure) of the four muscles. Patients were evaluated using Snellen and logMAR visual acuity charts, contrast sensitivity testing, color vision testing, stereopsis testing (TNO), and electronystagmography (ENG) for nystagmus waveforms, frequency, amplitude, and intensity. Group 1 patients showed a trend toward 1-line improvement in their visual acuity for distance on the logMAR and ETDRS charts (P=0.32); there was no improvement in group 2 patients. Contrast sensitivity improved significantly in both groups (P=0.03), as did stereopsis (P=0.02 [group 1], P=0.04 [group 2]). The amplitude and intensity of nystagmus showed a tendancy to decrease in both the groups in all gazes, although the frequency showed no change in either group. Intergroup variability on all the parameters was not statistically significant. Both retroequatorial recession of horizontal recti and the Hertle-Dell'Osso procedure showed a trend toward reducing ENG amplitude and improved contrast sensitivity and stereopsis in infantile nystagmus with null in primary position.

Effect of Horizontal Strabismus Surgery on the Refractive Status

Purpose: To evaluate the effects of horizontal strabismus surgery on the refractive and astigmatic status of eyes following horizontal muscle surgery using double-angle vector analysis.Materials and Methods: This was a retrospective analysis of 137 patients (250 eyes) conducted between February 1997 and October 2010 in patients who had unilateral or bilateral recession or monocular recession and/or underwent resection of horizontal muscles by a single surgeon. Refraction data were obtained at 1–2 weeks preoperative and at 4–6 weeks and 4–6 months postoperative. Surgically induced refractive changes were calculated using double-angle vector analysis.Results: The mean change in the spherical equivalent (SE) of the refraction was 0.23 ± 0.78 D for surgically induced refractive changes at 4–6 weeks postoperative (SIRC1; p < 0.0001) and 0.14 ± 0.85 D (p = 0.018) for surgically induced refractive changes at 4–6 months postoperative (SIRC2), indicating a small shift in the myopic direction with regression at 4–6 months. The mean amplitudes of the induced cylinders were 0.072 ± 1.22 D (p = 0.262) in SIRC1 and 0.20 ± 1.14 D (p = 0.012) in SIRC2, and the mean axis of the induced plus cylinder was 21.74° in SIRC1, indicating a small shift in the with-the-rule direction, but no statistically significant difference from zero (p = 0.331). The changes in the surgically induced refraction over time (SIRC d), ie, 0.05 ± 0.64 in SE (p = 0.255) and 0.09 ± 0.65 in the cylinder (p = 0.049), were stable. There was no significant correlation between the amounts of horizontal rectus muscle recession and/or resection and the cylinder power of individual induced astigmatism at 4–6 weeks after surgery (p = 0.266) and the myopic shift (p = 0.345). Moreover, there were no significant correlations between the ages of the patients and the spherical equivalent for SIRC1 (p = 0.858) and the induced cylinder for SIRC1 (p = 0.750).Conclusion: Horizontal rectus muscle surgery tended to induce a transient, statistically significant change in the spherical equivalent of refraction, with a myopic shift that was clinically not important. Our findings did not strongly support that the astigmatism induced changes. There was no correlation between the amount of recession and/or resection and the amount of induced refractive error.

Comparison of surgically induced astigmatism in patients with horizontal rectus muscle recession.

To compare surgically induced astigmatism (SIA) following horizontal rectus muscle recession surgery between suspension recession with both the "hang-back" technique and conventional recession technique. Totally, 48 eyes of 24 patients who had undergone horizontal rectus muscle recession surgery were reviewed retrospectively. The patients were divided into two groups. Twelve patients were operated on by the hang-back technique (Group 1), and 12 by the conventional recession technique (Group 2). SIA was calculated on the 1(st) wk, 1(st) and in the 3(rd) mo after surgery using the SIA calculator. SIA was statistically higher in the Group 1 all postoperative follow-up. SIA was the highest in the 1(st) wk, and decreased gradually in both groups. The suspension recession technique induced much more SIA than the conventional recession technique. This difference also continued in the following visits. Therefore, the refractive power should be checked postoperatively in order to avoid refractive amblyopia. Conventional recession surgery should be the preferred method so as to minimize the postoperative refractive changes in patients with amblyopia.

Long-term results of four horizontal rectus muscle recession in nystagmus treatment

Purpose: To report the long-term results of four horizontal rectus muscle recessions that were performed for infantile nystagmus syndrome treatment.Methods: In this case series, patients with infantile nystagmus syndrome who had four horizontal muscle recessions previously were recruited and ophthalmological examination and electronystagmography recordings were performed. Objectively, amplitude and frequency of nystagmus were measured from the recordings and the intensity was calculated. Visual acuity, stereopsis, and alignment were evaluated and compared with the preoperative and postoperative values.Results: The records of the 12 patients who had four horizontal rectus muscle recession surgery were evaluated and six patients (5 male, 1 female) who had regular follow-ups were included in this study. Mean follow-up was 14.17 ± 0.41 years (minimum 14 years, maximum 15 years) and mean age of patients at the last visit was 22 years (20-28 years). On subjective evaluation, two-thirds (4/6) of the patients were satisfied with the surgical results and had the impression that after surgery, nystagmus decreased in intensity and head posture improved. On objective evaluation, visual acuity was found to be the same, however, stereopsis improved (preoperatively and postoperatively median stereopsis was 600 sec arc vs 200 sec arc final). The decrease in nystagmus amplitude and frequency was still maintained.Conclusions: Nystagmus surgery on four horizontal rectus muscles has positive effects on binocular function and nystagmus parameters in the long-term follow-up. As we could not treat the primary pathology, the visual acuity was about the same but the decrease in nystagmus amplitude and frequency was still maintained with better stereopsis, and patient satisfaction.

Unilateral rectus muscle recession in the treatment of Duane syndrome

To determine the outcome of unilateral single horizontal rectus recession surgery in patients with Duane retraction syndrome. A retrospective review was conducted of 27 medical records of patients with Duane syndrome who underwent unilateral medial rectus recession for esodeviations and lateral rectus recession for exodeviations. The criteria for evaluating surgical success included improvement of abnormal head position, reduction of strabismus deviation, and preservation or improvement of stereoacuity. Patients had an average recession of 6.3 mm and were followed for an average of 4 years. Of the 27 patients treated with unilateral horizontal rectus muscle recession, 93% had a postoperative head turn of <10° in primary position and 85% an ocular deviation of <10(Δ). An excellent outcome, defined as a combination of stereoacuity of <100 arcsec, head turn <10°, and strabismus of <10(Δ), was achieved by 63% of patients. Unilateral single horizontal rectus muscle recession improves or eliminates head turn, corrects strabismus in primary position of gaze, and maintains good stereoacuity in a majority of patients with Duane syndrome.

Surgical Treatment in Patients with Double Elevator Palsy

To evaluate the effectiveness of surgical treatment performed in patients with double elevator palsy (DEP). Patients diagnosed with congenital DEP between April 2003 and March 2007 were included in the study. The cases with positive traction test had inferior rectus (IR) recession followed by full tendon width muscle transposition Knapp surgery or partial tendon width transposition operation, while those without positive traction test underwent transposition procedure alone. Transposition surgery was combined with recession and resection of horizontal rectus muscles in patients with exotropia according to the amount of horizontal deviation. Eyelid surgery was applied in patients with ptosis following strabismus surgery. The average age of 13 patients was 14+/-32.5 years (range, 3-60 years). Five patients (38%) were female and 8 patients (62%) were male. The mean preoperative hypotropia was decreased from 29.2+/-3.5 prism diopters (PD) (range, 16-45 PD) to 2.6+/-2.8 PD (range, 0-6 PD) postoperatively. The median amount of horizontal deviation in patients with exotropia (n=4) was 30 PD (range, 25-45 PD) preoperatively; it was reduced to 2 PD (range, 0-8 PD) postoperatively. Mean follow-up period was 14.1+/-2.8 months (range, 6-31 months). Five patients (38%) underwent eyelid surgery, and all achieved cosmetically satisfactory results. Transposition surgery alone or combined with IR recession is an effective procedure in treatment of double elevator palsy. In patients with moderate horizontal deviations, recession and resection of horizontal rectus muscles combined with transposition provide correction of the horizontal deviation at the same time.

Minimally invasive strabismus surgery

In 2007, I published in the British Journal of Ophthalmology a new, minimally invasive access technique for primary horizontal rectus muscle recession and plication and its results.1 I suggested performing...

Refractive effect of the horizontal rectus muscle recession

To determine refractive and corneal topographic changes after horizontal rectus muscles recession. In a noncomparative interventional case series, 49 eyes of 27 patients were evaluated in two groups: (1) exotropic patients (24 eyes) who underwent lateral rectus muscle(s) recession, and (2) esotropic patients (25 eyes) who underwent medial rectus muscle(s) recession. Full ophthalmic examination including cycloplegic automated refraction was carried out before, 1 and 3 months after surgery. Corneal topography was performed preoperatively and repeated at 3 months postoperatively. In eyes underwent medial rectus recession, there were statistically significant myopic shifts in spherical equivalent at month 1 (from +2.09+/-1.82 to +1.88+/-1.83 diopters, P=0.03) and in astigmatic power at both month 1 (from -0.85+/-0.67 to -1.15+/-0.65 diopter, P=0.04) and month 3 (from -0.85+/-0.67 to -1.16+/-0.65 diopter, P=0.01). Myopic shifts were also noted following lateral rectus recession; however, there were not statistically meaningful. Significant astigmatic axis shift, which was toward with the rule astigmatism, was detected only after lateral rectus recession at both month 1 (P=0.02) and month 3 (P=0.02). Corneal power measured by topography was also demonstrated a statistically significant reduction (less than 0.3 diopter) after recession of either medial (P<0.001) or lateral (P<0.001) rectus muscle. In spite of being statistically significant in some parts, the amounts of refractive and corneal topographic changes were not clinically remarkable. Therefore, it does not seem necessary to perform cycloplegic refraction early after horizontal rectus muscle recession; however, a precise refraction in all cases of strabismus should not be deferred later than 3 months.