Open Journal of Ophthalmology, 2013, 3, 1-3
http://dx.doi.org/10.4236/ojoph.2013.31001 Published Online February 2013 (http://www.scirp.org/journal/ojoph)
1
Silicone Band in the Surgical Treatment of Manifest
Exotropia
Lelio Sabetti, Antonio Berarducci, Domenico Di Lodovico
Eye Clinic, San Salvatore Hospital, University of L’Aquila, L’Aquila, Italy.
Received June 14th, 2012; revised August 15th, 2012; accepted August 23rd, 2012
ABSTRACT
Purpose: A silicone band was sutured anteriorly to the edge of the lateral rectus muscle neotendon during recession
surgery in order to reduce and delay the reoccurrence after exotropia surgery. Methods: Collected data of 12 patients (8
males and 4 females), aged 7 - 54 years with diagnosis of constant manifest exotropia and mean angle deviation in pri-
mary position of 15,04˚ (sd 1,18) for near and of 13,23˚ (sd 0,71) for distance. All patients underwent surgical treatment
consisting of lateral rectus recession and silicone band apposition in correspondence to the anterior edge of the lateral
rectus muscle neotendon. Results: A substantial reduction of the mean angle deviation was observed in all patients after
surgery. No adverse band-related effects were detected. Conclusion: The silicone band in the surgical treatment of
manifest exotropia could be a valuable aid in delaying the relapse thanks to its physical and structural features and to its
biocompatibility.
Keywords: Silicone Band; Exotropia; Recession; Lateral Rectus Neotendon
1. Introduction
Surgery represents the gold standard treatment in eyes
exodeviations. Several processes are implicated in the
exodeviation genesis but neurological lesions [1] are the
most frequent. Surgical technique is planned according to
deviation grade, sensory status and age of the patients
[2,3] and it includes bilateral lateral rectus recession and/
or unilateral medial rectus resection (which is strictly re-
lated with the primary deviation degree [4-6]). The use of
adjustable sutures might represent an effective aid in the
surgical management [7] as well as dominant or non-do-
minant eye surgery might produce different functional
outcomes [8,9].
Early post surgery complication is represented by sur-
gical hypocorrection [10] but the most important long
term complication is the long term deviation relapse [11].
Different factors are involved in the genesis of the re-
occurrence. Besides the clinical features of the primary
deviation and the abnormal wide neotendon regrowth in
correspondence of the new insertion (microscopic evi-
dence of Schwann cell degeneration both with an in-
crease of the neurofilaments density, axonal vacuoles and
hydric swelling [12,13]), level variation of some proteins
[14] such as fibronectin, proteoglycans, aggrecans and
laminin [15] seem to play a basic role in the resected mus-
cles.
The relapse management consist in surgery [16] in-
volving lateral rectus or medial rectus (unless previously
treated) [17,18].
According to several studies, relapse occurs in about
33% of cases and it might happen even following redo
surgery (although with a lower probability compared
with the first surgery [6,19,20]).
Most of the extreme eyes deviation (30˚ - 45˚ or 60Δ -
90Δ Δ= prismatic diopter) evolve to secondary strabis-
mus forms due to recession/resection surgical protocol,
extreme anisometropia or surgical trauma [21].
Some surgeons suggested a protocol consisting of a
free mucosal transplantation [21] to treat secondary de-
viations (over 45˚ equivalent to 90Δ).
However, exodeviation surgical correction is still rep-
resenting a difficult challenge due to the several and dif-
ferent clinical features which make difficult the surgical
approach and apparently aleatory outcomes.
2. Materials and Methods
The goal of our study was to estimate the effect of a sili-
cone band sutured anteriorly to the lateral rectus neoten-
don insertion during recession surgery in order to reduce
and delay the relapse in the surgical treatment of exot-
ropia.
The study was carried out at the S. Salvatore Hospital
of L’Aquila, in the Ophthalmology Unit, from June 2006
to December 2009. Data of 12 patients (8 males and 4

Silicone Band in the Surgical Treatment of Manifest Exotropia
2
females) aged between 7 - 54 years with well-known dia-
gnosis of manifest constant exotropia were collected; ma-
ximum follow-up at 42 months.
The pre surgical evaluation consisted in anamnesis (in
order to evaluate present complaint and previous ocular
history); complete ophthalmological assessment; cyclo-
plegic retinoscopy (using tropicamide 1% and cyclopean-
tolate 1%); best corrected and uncorrected visual acuity
check; orthoptic examination (cover-uncover test at both
near and distance fixation; ocular motility examination;
Worth Lights Test and microWorth test; Titmus Stereo
Test and Lang Stereo Test).
The presurgical orthoptic assessment revealed exo-
tropia in all patients; the mean deviation angle at near
was 15.4˚ (sd 1.18) and at distance was 13.23˚ (sd 0.71).
The Titmus Test showed absent stereopsis in 50% of
patients (6/12) and a complete perception of circles, with
average retinal image disparity of 100 arcs in the remain-
ing 50% of cases.
Ten over twelve patients (84%) suppressed one eye
with the Worth Lights Test and the remaining 16% of pa-
tients (2 over 12) was able to fuse with a proper prismatic
correction.
All the procedures were performed by the same ex-
perienced surgeon and consisted in 360˚ limbal conjunct-
tival peritomy, medial rectus muscles isolation, lateral
rectus recession and silicone band apposition (Novolene
5.0 suture) just anteriorly to the neotendon insertion,
layer suture.
3. Results
Patients underwent follow up assessment every 6 month;
final assessment performed at 42 showed the following
results: 8 over 12 patients (66%) presented exotropy
(mean angle deviation of 3.43˚ sd 0.87) at near fixation;
in the remaining 34% of cases (4 over 12) exoforia was
detected (mean angle deviation: 4˚ sd 0.73). Orthophoria
for distance was obtained in 25% of cases (3 patients
over 12) and exoforia was still present in 3 over 12 pa-
tients (25%) (mean angle deviation of 3.42˚ sd 0.58). In 6
over 12 patients residual small angle exotropia (<1.5˚ of
deviation). With regards of the sensory evaluation, in
50% of cases (6 over 12 cases) a modified stereoscopic
vision consisnting in perception of the fly, animals and
circles was detected, but with a retinal image disparity of
80 arcs. Sensory status check demonstrated suppression
in one eye during the test in 10 over 12 cases (84%),
while in the remaining 16% of patients (2/12) fusion was
obtained using an appropriate prismatic correction.
4. Discussion
According to several studies, resection/recession surgery
produces good outcomes in about 60% - 80% of patients
[22] and an early hypercorrection (4Δ - 6Δ) [23] seems to
represent the only positive predictive factor in the long
term success.
Some surgeons proposed to measure intraoperatively
the deviated lateral rectus neotendon width in order to
estimate the possible functional outcome [24]. A retro-
spective study involving 350 patients surgically treated
for exotropia demonstrated that a good long term out-
come (outbreak relapse mean time = 48 months [25] and
64 months [11]) could be achieved performing a postsur-
gical hypercorrection higher than 10Δ of isotropia [25].
Hypercorrections higher than 17Δ are often related
with consequent secondary isotropia; in these cases, the
greatest risk factor [26] is mainly represented by lateral
incomitance. A recent study in 2005 showed that hyper-
corrections higher than 20Δ need a subsequent surgical
treatment due to a consequent isotropia in 5%, 9% of the
patients [27].
Recently, a 20-year retrospective study involving pa-
tients who underwent exotropia surgery before age 10
suggested that stable eye alignment obtained in 11 year
old patients tends to be the same until age 30 [28].
The analysis of the results obtained in our study de-
monstrated a substantial reduction of the mean angle de-
viation at 42 months after surgery associated with a sig-
nificant improvement in terms of motor fusion and no
presence of flogistic reactions related to silicone band.
Stereoscopic sense remained unmodified and the sensory
status examination continued to show suppression in one
eye. Finally, ocular motility examination didn’t suggest
any duction disability.
In conclusion, the silicone band in the surgical treat-
ment of manifest exotropia could be a valuable aid in de-
laying the relapse thanks to its physical and structural
features and to its biocompatibility.
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