Augmented Medial Rectus Muscle Recession Versus Medial Rectus Recession With Posterior Scleral Fixation in Partially Accommodative Esotropia
Phase: NA
Conditions: Partially Accommodative Esotropia
Sponsor: Cairo University

Augmented Recession Vs. Posterior Scleral Fixation – Full Protocol 
 January 10th, 2015 
 
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AUGMENTED MEDIAL RECTUS MUSCLE RECESSION VERSUS MEDIAL RECTUS 
RECESSION WITH POSTERIOR SCLERAL FIXATION IN PARTIALLY 
ACCOMMODATIVE ESOTROPIA 
 
FULL PROTOCOL 
 
 
Principal investigator(s):  
Hala Elhilali, MD, MD, Professor of Ophthalmology, Cairo University 
Ahmed Awadein, MD, Professor of Ophthalmology, Cairo University 
 
Clinical Trials Registration Number: NCT02413463 
 
 
Submitted to Cairo University Ophthalmology Department Medical Research Approval 
Committee on December 10th, 2014  
 
Final revision approved on January 10th, 2015 
 
 
 
 
 
 
 

Augmented Recession Vs. Posterior Scleral Fixation – Full Protocol 
 January 10th, 2015 
 
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INTRODUCTION: 
 
The initial treatment of partially accommodative esotropia (PAET) is correction of the full 
hyperopic error. Surgery is needed if there is residual esotropia ≥ 12 prism diopters for distance 
and near, and/or if the patient is not attaining fusion 1. A variety of surgical approaches have been 
proposed to decide the surgical target angle on which the amount of muscle surgery is based. 
These strategies include: the standard formula 2, prism adaptation 3, and the enhanced 4 and the 
augmented surgical formulas 5. 
 
However overcorrection might occur with augmented recession, and often requires 
reduction of hyperopic correction to maintain alignment. Such overcorrection might carry the risk 
of development of consecutive exotropia later on 6, 7.  
 
Various methods have been described before to address variability in the angle of the 
deviation in esotropia including posterior scleral fixation 8, pulley fixation 9, slanting recession 10, 
combined recession-resection 11 and Y-splitting of the medial rectus muscle 12. While these 
modalities have been described before in the management of convergence excess esotropia 
because of their ability to reduce the variability in the angle especially for near, their value in 
PAET have not been adequately studied. 
 
The aim of this study is to evaluate whether posterior scleral fixation sutures can 
adequately address the variability of the angle of deviation in children with PAET while 
minimizing the risk of postoperative overcorrection. 
 

Augmented Recession Vs. Posterior Scleral Fixation – Full Protocol 
 January 10th, 2015 
 
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METHODS: 
 
A prospective controlled interventional study will be performed on patients with partially 
accommodative esotropia. An informed consent for the surgery will be obtained from all patients. 
All patients’ guardians will receive a thorough explanation of the study design and aims, and 
signed a written informed consent. 
All patients will receive a full ophthalmological assessment including history taking, measurement 
of uncorrected and best-corrected visual acuity, cycloplegic refraction, anterior segment 
examination, as well as a dilated fundus examination. 
 
In addition, all patients will have a detailed motor examination during the initial evaluation and at 
each follow-up period. The angle of misalignment will be measured by the prism and alternating 
cover tests for both distance and near with and without glasses. The angle of horizontal 
misalignment will also be measured in side gazes and in straight up and down gazes. Measurement 
of the angle of deviation in up and down gazes will be done by tilting the head, approximately 25 
degrees down and up respectively, with the patient fixing on a distance target. The difference 
between the angles of horizontal misalignment in up and down gazes will be used to calculate the 
amount of pattern strabismus if present. 
 
The ductions and versions in all cardinal directions of gaze will be analyzed before surgery and 
thereafter during the postoperative follow up visits. Underaction will be measured on a 4-point 

Augmented Recession Vs. Posterior Scleral Fixation – Full Protocol 
 January 10th, 2015 
 
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scale ranging from -1 to -4. Similarly overaction will be measured on a 4-point scale ranging from 
+1 to +4.  
 
In all patients cycloplegic refraction will performed using cyclopentolate 1% eye drops instilled 3 
times 10 minutes apart with the last time 30 minutes before refraction. Patients with hypermetropia 
with a spherical equivalent >= +1.5 D will then prescribed the full cycloplegic refraction and then 
re-evaluated with spectacles one month later. Patients who appear to have a partially 
accommodative esotropia defined as residual esotropia >8 PD for distance with spectacles will 
have repeat refraction using atropine 1% drops 3 times a days for 3 days before refraction. 
  
After ensuring that full cycloplegic refraction was prescribed, patients will then evaluated with 
glasses to identify those with partially accommodative esotropia without convergence excess. 
Patients will be included in the study if the residual distance angle with cycloplegic prescription 
was > 15PD. Patients with convergence excess esotropia, defined as the angle of deviation with 
glasses for near exceeding that for distance by 15 PD or more will be excluded from the study.  
 
Amblyopia will be defined as a difference of 0.3 logMAR in verbal children (3 lines on the 
standard logMAR visual acuity chart) or a strong unilateral fixation preference using an 
accommodative target in infants and preverbal children. All patients with amblyopia will be treated 
before surgery. In general amblyopia therapy was continued till there was no further improvement 
of visual acuity or fixation preference despite adequate compliance with therapy for an acceptable 

Augmented Recession Vs. Posterior Scleral Fixation – Full Protocol 
 January 10th, 2015 
 
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duration. Amblyopia will be treated following the standard clinical practice using part-time 
occlusion and in concordance with the PEDIG guidelines 13. Anisometropia is defined as a 
difference in the spherical equivalent of both eyes by 1 D or more. 
 
Patients with neurologic, ocular, or developmental disorders or follow-up less than 6 months will 
be excluded from the study. In addition, patients will be excluded if they showed oblique muscle 
dysfunction, vertical deviation, significant A or V patterns, paralytic or restrictive forms of 
strabismus, or had a history of prior eye muscle surgery.  
 
The smallest angle of deviation is defined as the corrected angle for distance. The largest angle is 
defined as the angle for near measured without correction. The angle disparity is defined as the 
difference between the largest and smallest angles. 
 
Patients will be randomly allocated using a random table to one of two groups. In one group 
bilateral augmented MR muscle recession will be performed (augmented group). In the other 
group bilateral MR muscle recession combined with posterior scleral fixation sutures will be 
performed (Faden group). 
 
The surgeries will be performed by one of two surgeons (HE, AA) using the same surgical 
technique. In both groups the medial rectus muscle will be exposed and hooked through a limbal 
approach. The muscle will then secured with 6-0 polyglactin (Vicryl, Ethicon, Somerville, NJ) 
sutures.  
 

Augmented Recession Vs. Posterior Scleral Fixation – Full Protocol 
 January 10th, 2015 
 
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In the augmented group, the medial rectus muscles will be recessed using standard tables 14 with 
the surgical dose targeting the average of the largest and smallest angles.  
 
In the Faden group, medial rectus muscle recession will be performed as described above with the 
surgical dose targeting the smallest pre-operative angle. The muscle will then fixated to the sclera 
using 6/0 polyester sutures placed in a mattress like with the anterior and the posterior sutures 
passing through both the edge of muscle and the sclera 12 mm and 14 mm from the muscle 
insertion, respectively. 
 
Patients will be followed up at 1 week, 1 month, 3 months and 6 months after surgery. The 
distance and near angles of deviation, with and without glasses, and the angle disparity will be 
measured at each follow up visit and the ductions and versions were assessed in all patients. 
 
Patients will be considered to have successful outcome if both the distance and near angles with 
spectacles were less than 8 PD esotropia/phoria. Patients who develop any exophoria/tropia, or in 
whom hyperopic correction needed to be reduced for treatment of a consecutive exotropia will be 
considered to be unsuccessful 6, 7, 15. In addition, patients will be further subdivided into 2 groups 
according to the preoperative angle disparity into those with angle disparity 20 PD or less and 
those with angle disparity more than 20 PD. The success rate in each subgroup will be calculated. 
 
For categorical variables (e.g., gender), percent distribution will be used. For continuous variables 
(e.g. age, angle of deviation), mean, range and standard deviation were used. Comparisons 
between the two groups will be done using t-test for independent samples for continuous variables 

Augmented Recession Vs. Posterior Scleral Fixation – Full Protocol 
 January 10th, 2015 
 
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and chi square test for categorical variables. Statistical analysis will be performed with SPSS for 
Windows (SPSS Inc., Chicago, IL). 
 
SAMPLE SIZE: 
An estimation of sample size was performed considering a study power of 0.8 with an alpha error 
of 0.05 aiming to detect a difference of 5 Δ in the postoperative angle disparity between the 2 
groups, assuming a postoperative standard deviation of 6 Δ 9. Based on this estimation, a total of 
24 eyes were found to be adequate in each group, and considering a 25% dropout during the 
follow-up, recruitment of 30 study subjects in each group will be targeted 
 
EXPECTED START DATE: 1 January 2015 
EXPECTED COMPLETION DATE: 31 December 2016 
 
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 January 10th, 2015 
 
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 January 10th, 2015 
 
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