ORIGINAL ARTICLE  
Pain Score in Adjustable  
Strabismus Surgery  
Sana Nadeem1  
1Department of Ophthalmology, Fauji Foundation Hospital, Rawalpindi  
ABSTRACT  
Purpose: To assess the pain experienced by patients at the time of suture adjustment using topical proparacaine  
hydrochloride 0.5% anesthesia, in adjustable suture strabismus surgery.  
Study Design: Prospective, interventional study.  
Place and Duration of Study: Eye department of Fauji Foundation Hospital, Rawalpindi from May, 2017 to  
March, 2019.  
Material and Methods: A prospective study was carried out to assess the pain experience of patients  
undergoing suture adjustment under topical proparacaine hydrochloride 0.5% anesthesia, during routine  
adjustable squint surgery. All surgeries were performed under general anesthesia with suture adjustment done 1  
hour or more after surgery when the effects of general anesthesia had worn off. Horizontal and vertical muscle  
recessions and resections were included along with inferior oblique surgeries, and transposition procedures. The  
patients were given the Wong-Baker FACES® Pain rating Scale; along with a Numeric Pain Rating Scalefrom 0  
to 10 (0 signifying no painand 10 signifying worst possible pain) on a proforma. The response of the patients  
was noted.  
Results: Thirty three patients who underwent adjustable strabismus surgery were included in this study. The  
mean age was 19.1 ± 11.1 years. The average number of muscles operated upon for each patient were 2.87 ±  
1.08. The patients’ response to the ‘Wong-Baker FACES® Pain rating Scale’ ranged from 0 to 8, with a mean of  
2.03 ± 1.81 SD. On the ‘Numeric Pain Rating Scale’ a similar response was obtained with a mean of 2.0 ± 1.82  
SD. Augmentation of anesthesia was not needed in any patient.  
Conclusion: Adjustment of sutures under topical proparacaine hydrochloride 0.5% anesthesia after strabismus  
surgery is a practical, comfortable and safe procedure.  
Key Words: Adjustable suture, Strabismus, Pain score, Pain scale, Topical anesthesia.  
How to Cite this Article: Nadeem S. Pain Score in Adjustable Strabismus Surgery. Pak J Ophthalmol. 2020, 36  
(2): 109-114.  
Doi: 10.36351/pjo.v36i2.912  
INTRODUCTION  
two-stage adjustable strabismus technique, with the  
surgery performed under general anesthesia and suture  
adjustment done later under topical anesthesia, 4 24  
hours after surgery to fine tune the results1-3. Tripathi3  
et al believe that adjustable strabismus surgery is the  
procedure of choice for all fit and willing patients.  
Awadein and Guyton et al4 recommend adjustable  
sutures in all patients including infants and children as  
well.  
Adjustable suture strabismus surgery was first  
described in 1907 by Bielchowsky thus allowing the  
surgeon a second chance at realigning the eyes and  
improving his results. Jampolsky in 1975 described a  
Correspondence to: Sana Nadeem  
Assistant Professor, Department of Ophthalmology  
Fauji Foundation Hospital, Rawalpindi  
109  
Pakistan Journal of Ophthalmology, 2020, Vol. 36 (2): 109-114  
Pain Score in Adjustable Strabismus Surgery  
Topical  
anesthesia  
with  
proparacaine  
and stereopsis were assessed by the Titmus fly test and  
Worth four dot test in every case. A thorough eye  
examination was performed including fundus and  
intraocular pressures. In case of significant oblique  
overaction, paralytic or vertical strabismus, fundus  
torsion was also assessed with the indirect  
ophthalmoscope. All surgeries were performed by the  
hydrochloride 0.5% has been a safe and effective tool  
during the final suture adjustment and has been  
advocated by many strabismus surgeons4,5,6. Seijas7 et  
al recommend topical anesthesia only, for strabismus  
surgery even without the need of a general anesthetic.  
The rationale of our study was to assess the pain  
score at the time of suture adjustment after strabismus  
surgery using two scales, in order to find out if it is a  
comfortable and effective procedure.  
author under general anesthesia.  
A
drop of  
phenylephrine 10% (Ethifrin®) was instilled into the  
conjunctival sac prior to the surgery in each eye. The  
fornix approach for strabismus surgery was used in  
every case. Each muscle was hooked, and then secured  
with a double armed 6 0 vicryl (polyglactin 910)  
absorbable suture, which was passed through the  
sclera at muscle insertion, or transposed above or  
below the insertion in case of “A” or “V” patterns, in a  
‘hang-back’ fashion. The muscles placed for  
adjustable purpose were held in position by Guyton‟s9  
modification of the sliding noose knot, which was  
fashioned with a 6 0 vicryl suture. The amount of  
‘hang-back’ recession was calculated for each patient  
using standard tables10-12. The traction suture for  
holding the sclera for postoperative adjustment was  
created with ethibond 5-0 in every case. For the non-  
adjustable recessions, the muscle was tied and allowed  
to ‘hang-back’ from its insertion, with the amount of  
recession calculated as required. For resections, the  
amount of resection was overcorrected by 2 mm, and  
allowed to ‘hang-back’ for this distance, to be adjusted  
if required postoperatively. At least one muscle was  
kept on an adjustable sliding noose knot per case; with  
complex strabismus, all muscles were kept on  
adjustable sutures.  
MATERIAL AND METHODS  
A total of 33 patients were included in this study by  
convenient sampling technique. The study was carried  
out in the Department of Ophthalmology, Fauji  
Foundation Hospital, Rawalpindi; a tertiary care  
teaching hospital affiliated with the Foundation  
University Medical College. Approval from the ethical  
committee was taken. Horizontal, vertical and  
complex strabismus cases were included along with  
patients with a previous history of strabismus surgery.  
Myasthenia gravis and uncooperative children less  
than 7 years of age were excluded.  
A detailed ocular assessment was done and best-  
corrected visual acuity was documented for every  
case. Refractive correction was given to the patients  
before surgery. The prism cover test (PCT) was used  
to assess the preoperative angle of deviation with the  
refractive correction in place, for both near and  
distance in primary gaze position, as well as in 25° of  
upgaze (chin down) and 35° of downgaze (chin up)8,  
right and left gaze, and head tilt in case of paralytic  
strabismus. In certain cases of sensory strabismus with  
poor fixation, the Krimsky test was used for analysis  
of the angle or a pen torch used as a target for near and  
distance. The distance angle in primary position with  
the refractive correction in place was considered as the  
angle of deviation in all cases, and the surgical  
alignment was sought to correct this angle, although at  
the time of suture adjustment, both near and distance  
alignment was corrected. Exception to this was  
accommodative refractive esotropia, for which the  
near deviation with distance spectacles in place was  
considered for correction of the alignment.  
All patients were assessed for alignment and final  
adjustment at least 1 hour or more after surgery, in the  
recovery room, to allow the effects of general  
anesthesia to wear off. The eyes were anesthetized  
topically with Alcaine® (proparacaine hydrochloride  
0.5%) eye drops a few times. The patients were fully  
conscious at the time of suture adjustment and were  
not placed on a monitor. However, they were observed  
for discomfort, syncope or oculocardiac reflex. The  
patients were assessed with the cover-uncover test at  
distance and near, with a torch light for distance if the  
vision was blurred, or a distance readable target; and  
for near an accommodative target was used. If the  
alignment was satisfactory, with no movement on  
cover testing, the sutures were tied off in their existing  
position, held in place by the sliding noose, which was  
removable after tying the ends of the muscle sutures.  
The measurements were taken by the operating  
surgeon and repeated one day prior to the surgery, to  
obtain maximum cosmesis. Extraocular motility was  
checked with muscle overaction graded from +1 to +4  
and underaction graded from -1 to -5. Binocular vision  
Pakistan Journal of Ophthalmology, 2020, Vol. 36 (2): 109-114  
110  
Sana Nadeem  
Thereafter, the traction knot was cut, and the  
conjunctiva was sutured with at least one 6-0 vicryl  
suture. The final tying off point was orthotropia or  
maximum possible under-correction as required. In  
cases of exotropia, the goal was orthotropia or mild  
esotropia. In cases of esotropia, the goal was either  
orthotropia, if achieved, or slight under-correction.  
Topical steroid and antibiotic drops and ointment were  
instilled. No bandage was applied in any case. The  
next day, the patients were asked about their pain  
experience by giving them a proforma with two scales;  
the ‘Wong-Baker FACES® Pain rating Scale13and a  
‘Numeric Pain Rating Scale14 (NPRS)‟.  
number of muscles operated upon, were filled on each  
performa. The results were noted, tabulated and  
analyzed using SPSS statistics version 20. Frequencies  
and percentages were calculated for age, gender, type  
of strabismus, surgical procedure performed, number  
of muscles and the pain score. Paired t-tests were used  
to assess the effect of number of muscles operated  
upon on the pain score.  
RESULTS  
A total of 33 consecutive patients with strabismus  
presenting to us were included in this study. The mean  
age was 19.1 ± 11.1 years (range 7 69). Majority of  
the patients were female (81.8%) and the rest were  
male (18.2%). The deviation type in the majority  
of the patients was exotropia in 14 (42.5%) cases  
(Table 1).  
The Wong-Baker scale is a pain grading scale  
which was developed by Donna Wong and Connie  
Baker, depicting a series of 6 faces starting from a  
happy face with 0 or ‘no hurt’ to a weeping face at 10  
representing ‘worst pain imaginable’ (Figure 1). This  
scale was initially developed for children, but  
nowadays is used for patients 3 years and above. The  
Numeric Pain Rating Scale14 is a unidimensional  
assessment of pain severity in adults and is a  
segmented numeric version of the Visual analog scale  
(VAS). It ranges from 0-10 with 0 representing ‘No  
pain’, 5 representing „Moderate pain’ and 10  
representing „Worst possible pain’ (Figure 2).  
Table 1: Type of Deviation.  
Type of Deviation  
Frequency (Percent)  
Exotropia  
Esotropia  
14 (42.4)  
7 (21.2)  
2 (6.1)  
4 (12.1)  
1 (3)  
3 (9.1)  
2 (6.1)  
13 (39.4)  
4 (12.1)  
13 (39.4)  
2 (6.1)  
1 (3)  
Esotropia & DVDɸ  
Exotropia & Hypertropia  
Esotropia & Hypertropia  
Esotropia & Hypotropia  
Exotropia & Hypotropia  
Horizontal  
Horizontal and Vertical  
Complex€  
Horizontal & Complex€  
Horizontal, Vertical & Complex€  
ɸ Dissociated vertical deviation  
€ Sensory, Monocular elevation deficit, paralytic strabismus,  
nystagmus or DVD  
Fig. 1:  
Table 2 outlines a list of surgeries performed for  
the primary deviation. The average number of muscles  
operated upon for each patient were 2.87 ± 1.08  
(Range 2-6).  
Table 2: Surgical Procedures Performed for Primary  
Deviation.  
A. Horizontal Muscle Surgery.  
Fig. 2: Numeric Pain Rating Scale.  
Surgery  
Frequency (Percent)  
BLRc¶  
8 (24.2)  
8 (24.2)  
1 (3)  
7 (21.2)  
2 (6.1)  
2 (6.1)  
BMRc§  
The patients were explained each scale and asked  
to point their level of pain on each scale with a finger.  
The name, age and gender of the patient, type of  
strabismus, diagnosis, surgery performed and the  
MRc¤ + LRs×  
MRsø + LRcĦ  
BLRc+ MRsø  
BMRc§ + LRs×  
111  
Pakistan Journal of Ophthalmology, 2020, Vol. 36 (2): 109-114  
Pain Score in Adjustable Strabismus Surgery  
ophthalmic solution or proxymetacaine is topical  
anaesthetic of the aminoester drug group, which  
antagonizes the voltage-gated sodium channels to alter  
permeability of neuronal membranes.15 Topical  
anaesthesia has been found to be a safe and effective  
tool during suture adjustment in strabismus surgery4.  
Sharma et al5 reported that adjustable strabismus  
surgery under topical anaesthesia was a safe and better  
option than conventional recession-resection surgery  
for concomitant Exodeviation. However, Seijas et al7  
reported oculocardiac reflex in 3 patients for which  
atropine was given. They also suggested that  
monitoring by anaesthetist was necessary because of  
vagal reflex. None of our patients experienced any  
complication like that.  
Surgery  
Frequency (Percent)  
MRc¤  
2 (6.1)  
1 (3)  
1 (3)  
1 (3)  
LRc*  
LRcĦ +MRsø+ MRc¤  
None  
Bilateral recessions  
Bimedial recessions  
Bimedial resections  
Unilateral medial rectus recession  
Unilateral lateral rectus resection  
Unilateral medial rectus resection  
§
¥
¤
×
ø
Ħ
Unilateral lateral rectus recession  
Unilateral lateral rectus recession  
*
B. Vertical Muscle Surgery.  
Frequency  
(Percent)  
Mazow ML16 also described good results  
following adjustable suture strabismus surgery but  
stressed upon the importance of good case selection.  
Similarly 81.8% success was reported by Park JM et al  
in adjustable suture strabismus surgery17.  
Surgery  
None  
17 (51.5)  
4 (12.1)  
6 (18.2)  
1 (3)  
1 (3)  
3 (9.1)  
1 (3)  
Unilateral IOα myectomy  
Bilateral IOα myectomies  
IRcϠ +IOα myectomy  
Bilateral IOα myectomy + SRΩ transposition  
IRcϠ + SRcƩ  
IRcϠ  
Nowadays, many surgeons are striving for  
strabismus surgery under local anaesthesia only  
including retrobulbar, peribulbar, subconjunctival and  
subtenon injections or even topical anaesthesia only.  
For local anaesthetic injections, although the  
complications of general anaesthesia are avoided, at  
least 6 hours are required before adjusting sutures, to  
allow the effects of the local anaesthetics to wear  
off.18-21We prefer general anaesthesia for our  
strabismus surgeries in all cases, with suture  
adjustment under topical proparacaine hydrochloride  
0.5% drops only, after 1 hour or more has elapsed after  
surgery, at which time the patient is fully conscious,  
able to obey commands and no longer under the  
effects of the general anaesthetics. This provides an  
accurate assessment of the residual strabismus.  
α
Ʃ
Inferior oblique  
Superior rectus recession  
Ω Superior rectus  
Ϡ
Inferior rectus recession  
The patients‟ response to the ‘Wong-Baker  
FACES® Pain rating Scale’ ranged from 0 to 8, with a  
mean of 2.03 ± 1.81 SD, signifying ‘hurts little bit’.  
On the ‘Numeric Pain Rating Scale’ a similar response  
was obtained with a mean of 2.0 ± 1.82 SD (Range 0 –  
8), signifying mild discomfort. Only one patient  
complained of significant pain, rating 8 on both scales,  
but in this case too, no additional anaesthesia was  
needed and adjustment was performed successfully.  
She also had all three muscles on adjustable sutures,  
and this could have contributed to her discomfort.  
However, no correlation between the number of  
muscles operated upon and the pain scales was  
observed. 10 patients (30.3%) reported no pain  
whatsoever, scoring 0 on both scales. No complication  
of any kind was seen in any case during the suture  
adjustment procedure.  
In our study, we found suture adjustment under  
topical proparacaine hydrochloride 0.5% to be safe,  
comfortable and reliable. All patients reported a good  
experience, with no or mild pain during suture  
adjustment, ranging from 0-4 on both scales, with the  
exception of one lady who reported significant pain at  
a rating of 8 on both scales. The number of muscles  
operated upon did not correlate with excessive pain on  
the pain scales. Augmentation with other anaesthetic  
agents was not needed in any case, and neither was a  
reoperation required for any patient at a later time. No  
complications were seen during adjustment, and all  
patients were cooperative and adjusted on the same  
day. Oculocardiac reflex was not observed in any  
DISCUSSION  
Adjustable suture strabismus surgery has been done  
under many different types of anaesthesia. General  
anaesthesia is preferred for the initial procedure and  
final suture adjustment is done under topical  
anaesthesia. Proparacaine hydrochloride 0.5%  
Pakistan Journal of Ophthalmology, 2020, Vol. 36 (2): 109-114  
112  
Sana Nadeem  
8. Kekunnaya R, Mendonca T, Sachdeva V. Pattern  
strabismus and torsion needs special surgical attention.  
Eye (London). 2015; 29 (2): 184-90.  
9. Deschler EK, Irsch K, Guyton KL, Guyton DL. A  
new, removable, sliding noose for adjustable-suture  
strabismus surgery. J AAPOS. 2013; 17 (5): 524-7.  
10. Coats DC, Olitsky SE. Strabismus surgery and its  
complications. Springer: Berlin, 2007. P 37-39.  
11. Yanoff M, Duker JS. Ophthalmology. Third Edition.  
Mosby: St. Louis, 2009; p 1331-1338.  
patient during suture manipulation. Topical  
anaesthesia also saved time compared to the local  
anaesthesia procedures.  
Limitations of this study are small sample size, but  
still we want to share our thoughts on adjustable  
strabismus pain score at this time. The findings of our  
study suggest adjustable strabismus surgery as a good  
technique for better cosmetic and functional results.  
12. Lueder GT, Archer SM, Hered RW, Karr DJ, Kodsi  
SR, Kraft SP, et al. Pediatric Ophthalmology and  
Strabismus. Section 6. Basic and Clinical Science  
Course. American Academy of Ophthalmology. San  
Francisco. 2015-2016; p 131-182.  
13. Wong-Baker FACES Pain Rating Scale (Internet)  
Wikipedia Contributors. Wikipedia, The Free  
Encyclopedia; 4 December 2018 [cited 30 April 2019]  
Available from:  
14. Numeric Pain Rating Scale (Internet) Physiopedia  
contributors. Physiopedia; 26 April 2019 (cited 30  
April 2019) Available from:  
CONCLUSION  
Final suture adjustment under topical proparacaine  
hydrochloride 0.5% drops is a safe, effective and  
comfortable procedure, with minimal pain experienced  
by patients.  
Ethical Approval  
The study was approved by the Institutional review  
board/Ethical review board.  
Conflict of Interest  
Authors declared no conflict of interest  
15. Proxymetacaine (Internet) Wikipedia Contributors.  
Wikipedia, The Free Encyclopedia; 15 March 2018  
[cited 1 May 2019] Available from:  
Author’s Designation and Contribution  
Dr. Sana Nadeem; Assistant professor: Concept and  
Study Design, Drafting of Manuscript, Data Collection  
& Analysis, Final review.  
16. Mazlow ML, Fletcher J. Selection of patients and  
results of 25 years of topical anesthesia and adjustable  
suture surgery. Am Orthopt J. 2013; 63 (1): 85-91.  
17. Park JM, Lee SJ, Choi HY. Intraoperative adjustable  
suture strabismus surgery under topical and  
sunconjunctival anesthesia. Ophthalmic Surg Lasers  
Imaging, 2008; 39 (5): 373-8.  
18. Hakim OM, El-Hag YG, Haikal MA. Strabismus  
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2005; 9 (3): 279-284.  
19. Santhan KSG, Kelkar JA, Arora ER. Our experience  
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20. Vallés-Torres J, Garcia-Martin E, Fernández-  
Tirado FJ, Gil-Arribas LM, Pablo LE, Pea-Calvo P.  
Contact topical anesthesia versus general anesthesia in  
strabismus surgery. Arch Soc ESP Oftalmol. 2016; 91  
(3): 108-13.  
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