Anterior segment optical coherence tomography for identifying muscle status in strabismus surgery

Anterior segment optical coherence tomography （AS-OCT） finds very few indications in the domain of strabismus surgery. Current applications remain restricted to determining limbus-muscle insertion distance and anterior segment changes after strabismus surgery. We discuss two cases of operated strabismus surgery where AS-OCT imaging helped in identifying the operated eye and/or extra ocular muscles （EOM） and thus proved instrumental in planning and management.

AB075.Population trends in adult strabismus surgery

Background:To review the trends in adult strabismus procedures in Ontario from 2000-2014.Methods:A population based,retrospective data analysis was conducted.Ontario Health Insurance Plan billing claims for strabismus procedures were collected and subdivided by number of muscles repaired,the use of adjustable sutures and repeat procedures,adjusted by the total adult population.The number of Ophthalmologists performing adult strabismus surgery was also analyzed,subdivided by high volume and low volume surgeons.Results:From 2000-2014,per 100,000 adult population,the number of total strabismus surgeries in Ontario increased 29.1%;single muscle surgery increased 25.0%,two muscle surgery increased 46.3%,and three or more muscle surgeries increased 8.3%.During the study period,strabismus procedures using adjustable sutures increased 26.1%and repeat procedures increased 65.1%.The number of surgeons performing adult strabismus surgery decreased 21.7%from 2000-2014.In 2014,88.4%of surgeries were performed by 29.8%of all of surgeons who performed adult strabismus surgery.Conclusions:From 2000-2014,more strabismus surgery was performed in adults by fewer surgeons from 2000-2014.The number of adult strabismus surgeries in Ontario increased since 2000,including procedures using adjustable sutures and repeat procedures.These changes may be due to increases in healthcare funding and an increased awareness of the functional and psychosocial benefits of strabismus surgery.

Consecutive Exotropia after Convergent Strabismus Surgery—Surgical Treatment

Purpose: In this study the results of consecutive exotropia surgical treatment by using different surgical technics are presented. Methods: This study included 34 patients, aged 21 to 47 years (mean 27.9), who underwent medial rectus muscle advancement alone or in combination with medial rectus resection and/or lateral rectus recession. The mean interval between original surgery and surgery for consecutive exotropia was 8.5 years (range: 5.5 years to 14 years). Most of patients had 2 and more prior surgeries (73.5%) sold by an adduction deficit (47.06%). Results: The overall mean preoperative exodeviation was 35.12 ± 10.13 PD. Satisfactory alignment (within 10 PD of orthophoria) was achieved in 20 patients (58.8%) at 10 days after surgery and 24 patients (70.5%) at final 6-month follow-up. The most common surgical procedures were unilateral MR advancement and LR recession—47%. Conclusion: Medial rectus advancement is an effective method of surgical treatment, especially in cases with adduction limitation, but the risk of the eyelid fissure narrowing in cases of MRM advancement more than 5 mm associated with resection is present. In our opinion for reducing this risk in cases of XT with big angle of deviation, performing a smaller amount of advancement associated with recession of LRM can prevent the development of a such complication.

Strabismus surgery distribution during 10-year period in a tertiary hospital

Background There is no large population-based study of the distribution and changing trend of strabismus surgeries in China.This study aimed to investigate the distribution and the changing trend of strabismus surgery in a tertiary hospital of China.Methods A retrospective study of all the strabismus surgeries performed in Beijing Tongren Eye Center from 2003 to 2012 was carried out.Characteristics analyzed included the type of strabismus,age,and gender.Results Totally 26 524 strabismus surgeries were performed in Tongren Eye Center during the 10-year period.The number of surgeries increased steadily from 1 507 in 2003 to 3 482 in 2008 and slightly decreased to 3 124 in 2009,but there was a sharp drop to 2 569 in 2010 and then kept relatively steady at 2 760 in 2011 and 2 463 in 2012.Intermittent exotropia （30.3%） was the most common among all kinds of strabismus.The number of strabismus surgeries performed on children under 12 years of age （43.60%） was significantly higher than those of the other age groups （P 〈0.05）.Unilateral superior oblique paralysis was the most common subtype of paralytic strabismus （8.64%）.Conclusions The type distribution of strabismus surgery has changed during the recent decade.The age and type distribution of different strabismus remained basically constant,among which intermittent exotropia was the most common.

Setting up a heart rate alarm limit to decrease oculocardiac reflex during strabismus surgery in children

The aim of this paper is to investigate a method which may decrease the incidence and severity of oculo-cardiac reflex(OCR)without drugs.One hundred and sixty children undergoing strabismus surgery were allo-cated to two groups using double-blind randomization.OCR was defined as a decrease of more than 10%from the baseline heart rate during operation.An alarm sounded and a lamp flashed as soon as OCR occurred in group I,and neither of the above happened in group II.OCR occurred(1.151±0.858)times in group I and(2.287±1.371)times in group II(P<0.05).Heart rate decreased by(23±19)bpm in group I and(35±28)bpm in group II(P<0.05).The duration of OCR in group I and group II was(4.36±4.26)s and(7.62±6.41)s,respectively(P<0.05).The recovery time for group I and group II was(15.36±13.28)s and(32.36±19.57)s,respectively(P<0.05).The numbers of times of interruption were 8 in group I(10%)and 26 in group II(32%)(P<0.01).This method significantly decreased the incidence and severity of OCR during stra-bismus surgery in children.

Design and Efficacy of Surgery for Horizontal Idiopathic Nystagmus with Abnormal Head Posture and Strabismus

The design and efficacy of surgery for horizontal idiopathic nystagmus （HIN） with abnormal head posture and strabismus were investigated. Different surgical procedures were selected according to the angle of head turn in 44 cases of HIN with abnormal head posture and strabismus. For patients with a head turn of 15° or less, the Anderson procedure was used; the yoke muscles were recessed upon slow-phase. For patients with a head turn between 15° and 25°, the surgery was designed as a Kestenbaum 5-4-4-5 procedure. For patients with a head turn of 25° or more, the surgery was designed as a Parks 5-8-6-7 procedure. The surgery to correct the abnormal head posture was performed on the fixating eye while that to correct the deviation was then performed on the non-fixating eye at the same time. The amount of surgery of the horizontal rectus muscles on the nonfixating eye was sum of the angle of head turn and the degree of deviation, which was calculated as follows： recession/resection amount of medial and lateral rectis/2×5=angle of head turn±degree of deviation. The results showed as follows： （1） Visual acuity： the visual acuity in the primary ocular position increased two lines or more in 35 patients, accounting for 79.55%. Nine patients had no or only one-line improvement, accounting for 20.45% of the entire study population; （2） The degree of deviation in the primary ocular position： 37 cases had a normal primary ocular position or the degree of deviation ≤8△ after surgery, accounting for 84.09%. Six patients had a residual degree of deviation of 8△―15△, accounting for 13.64%. One patient had a residual degree of deviation 〉20△, accounting for 2.27% of the patients examined; （3） Abnormal head posture： 34 patients had a normal head posture or a head turn of less than 5°, accounting for 72.27%. Eight patients had a residual head turn of 5°―15°, accounting for 18.18%. Two patients had a head turn of 15°― 25°, accounting for 4.55%. It was concluded that different surgical procedures based on the angle of head turn and the relationship between deviation and null zone can eliminate anomalous head posture, correct deviation, and improve vision acuity in the primary ocular position simultaneously.

Effectivity of intraoperative adjustable suture technique in horizontal strabismus

AIMTo compare the long-term effectivity of intraoperative adjustable suture technique with traditional non-adjustable strabismus surgery.

Post-operative strabismus control and motor alignment for basic intermittent exotropia

AIM：To assess strabismus control and motor ocular alignment for basic exotropia surgery at 5y follow-up.METHODS：The medical records of 80 consecutive patients aged less than 17 years of age,who underwent surgery for basic exotropia by a single surgeon between years 2000 to 2009 and completed a minimum of 5y follow-up post-operatively were reviewed.Pre- and post-operative characteristics were documented at 1wk,6mo,1,3 and 5y follow-up.Subjects at 5-year follow-up were assigned to the success group if they had a postoperative angle of deviation within 10 prism diopters of exotropia or within 5 prism diopters of esotropia for distance on prism cover test,and had moderate to good strabismus control.The remaining subjects were assigned to the failure group.RESULTS：Post-operative surgical success at one week was 75%,which decreased to 41% at 5y follow-up.The success group was noted to have more patching pre-operatively（P=0.003）.The duration of patching a day（P=0.020） and total duration of patching preoperatively（P=0.030） was higher in the success group.Surgical success at 1y（P=0.004） and 3y（P=0.002） were associated with higher surgical success at 5y follow-up.CONCLUSION：Post-operative motor alignment and strabismus control for basic exotropia surgery at 1y and beyond is associated with higher exotropia surgery success at 5-year follow-up.There is an association between pre-operative patching and 5-year surgical success of basic intermittent exotropia surgery.

Congenital dysplasia involving both medial and inferior recti: clinical features and surgical outcomes

AIM: To investigate the clinical features and surgical outcomes of congenital dysplasia involving both inferior recti(IR) and medial recti(MR) muscles.METHODS: A retrospective review was conducted including cases of simultaneous congenital dysplasia of IR and MR that were diagnosed and surgically treated at the Zhongshan Ophthalmic Center, Sun Yat-sen University, China, from July 2009 to November 2019. Ocular motility, ocular alignment at distance(6 m) and near(33 cm) by prism alternating cover test and stereoacuity were assessed in all patients before and after surgery. RESULTS: A total of five patients(four males and one female;three with right eye and two with left eye congenital dysplasia) were included in this review. The patients ranged in age from 10 to 42 y(21±13.4 y). The main clinical findings were hypertropia and exotropia of the affected eye, along with motility limitations in adduction and depression. Lateral rectus(LR) recession/transposition combined with IR resection was performed in one case. Two scheduled surgeries were performed in four cases, with one involving superior rectus recession and IR resection and the others LR recession and MR resection. Mean±SD pre-surgical exotropia of 51.0±31.11 prism diopter(PD) and hypertropia of 29.20±7.12 PD in the primary position were decreased to 3.6±12.90 and 3.2±10.09 PD, respectively, at two years after surgery, with a success rate of 60% and an undercorrection rate of 40%. CONCLUSION: The main clinical features associated with simultaneous MR/IR congenital dysplasia are hypertropia and exotropia of the affected eye along with motility limitations in adduction and depression. Scheduled two-stage surgeries achieved a success rate of 60%.

Outcomes of half-width vertical rectus transposition augmented with posterior fixation sutures for sixth cranial nerve palsy

AIM:To describe the experience with half-width vertical muscles transposition(VRT)augmented with posterior fixation sutures.METHODS:The clinical charts of all patients,who underwent half-width VRT augmented with posterior fixation sutures for sixth cranial nerve palsy from January 2003 to December 2018,were retrospectively reviewed.For each patient,pre-and post-operatively,the largest measured angle was used for the calculations,usually resulting with the angle for distance,except in young infants,where measurements were made at near fixation using the Krimsky test.RESULTS:Fifteen patients met the inclusion criteria for the study,of them 9(60.0%)had also medial rectus muscle recession at the time of surgery.Mean follow-up period was 21.4±23.2mo(range 1.5-82mo).Preoperative mean esotropia was 51.3±19.7 prism diopter(PD;range 20-90 PD).Postoperative mean deviation on final follow-up was 7.7±20.2 PD(range-40 to 35 PD;P=0.018).In all patients with preoperative abnormal head position,improvement was noted.Ten(66.7%)patients had improvement in abduction and 10(66.7%)patients reported improvement in their diplopia,by final follow-up.The addition of medial rectus recession was correlated with a larger change in postoperative horizontal deviation compared to baseline(P=0.026).Two(13.3%)patients developed a vertical deviation in the immediate postoperative period which had resolved in one of them.CONCLUSION:Half-width VRT augmented with posterior fixation suture,with or without medial rectus muscle recession,is an effective and safe procedure for esotropia associated with sixth cranial nerve palsy.A major improvement in the angle of deviation is expected.Most patients will have improvement in their abnormal head position and diplopia.