Open Journal of Ophthalmology, 2013, 3, 19-23
http://dx.doi.org/10.4236/ojoph.2013.31006 Published Online February 2013 (http://www.scirp.org/journal/ojoph)
19
Strabismus in Cases of Cataract in Pediatric Age Group*
Shreya M. Shah, Mehul A. Shah, Pramod R. Upadhyay, Geetopam B. Bardoloi, Drashti Netralaya#
Drashti Netralaya, Dahod, India.
Received October 21st, 2012; revised November 21st, 2012; accepted November 28th, 2012
ABSTRACT
Purpose: To investigate the epidemiology of strabismus in cases of pediatric cataracts. To assess visual outcome fol-
lowing orthoptic treatment for amblyopia in cases of cataracts in the pediatric age group. Methods: This was a
retrospective cohort study. We investigated a consecutive series of pediatric patients with congenital, developing, or
traumatic cataracts who underwent surgery between January 1999 and April 2012 at our center. Patient demographics,
cataract type, presenting symptoms, surgical intervention, postoperative visual acuity, and follow-up refractive changes
were recorded. Results: In total, 1331 eyes of 1043 children were included: unilateral cataracts were present in 785
(59%) eyes. There were 605 (45.5%) traumatic and 726 (54.5%) non-traumatic cases. Ages at surgery ranged from 1 to
215 months. All eyes were examined for ocular alignment; 66 (5%) were found to manifest strabismus. Deviation was
significantly associated with age at intervention (p < 0.001), sensory nystagmus (p < 0.001), and etiology of cataracts (p
< 0.001). We found significant differences in visual outcome following amblyopia therapy (p < 0.001). Conclusions:
Surgical treatment with intraocular lens implantation in children with congenital, developmental, or traumatic cataracts
is effective for visual rehabilitation. Orthoptic treatment made a significant difference in visual outcome (p < 0.001).
Keywords: Pediatric Cataract; Visual Outcome; Traumatic Cataract; Developmental Cataract; Congenital Cataract
1. Introduction
Childhood cataracts are responsible for 5% - 20% of
blindness in children worldwide and for an even higher
percentage of childhood visual impairment in developing
countries [1-5]. The overall incidence of clinically sig-
nificant cataracts (unilateral or bilateral) in childhood is
unknown, but has been estimated to be as high as 0.4%.
[6,7]. The prevalence of childhood cataracts varies from
1.2 to 6.0 cases per 10,000 infants. Pediatric cataracts are
responsible for more than 1 million cases of childhood
blindness in Asia. In developing countries, such as India,
7.4% - 15.3% of childhood blindness is due to cataracts.
[8,9] Internationally, the incidence is unknown. Although
the World Health Organization and other health organi-
zations have made great progress in vaccination and dis-
ease prevention, the rate of congenital cataracts remains
much higher in underdeveloped countries.
The visual results of cataract surgery in children have
generally [10,11] been poorer than in adults [1-3,6,11,12].
This difference is due, in part, to the various types of am-
blyopia that develop in children with cataracts, the asso-
ciation of nystagmus with early onset cataracts, and the
presence of other ocular abnormalities that adversely
affect vision in eyes with developmental lens opacities.
Since the introduction of the aspiration technique of ca-
taract removal by Scheie in 1960 [13], surgical proce-
dures for the removal of the lens in childhood have im-
proved [14,15], and earlier surgery for congenital cata-
racts has been encouraged [16-18]. Strabismus and am-
blyopia are important causes of poor visual outcome.
[18].
Any opacification of the lens and its capsule in chil-
dren is defined as a pediatric cataract. Pediatric cataracts
can be unilateral or bilateral. They can be subdivided ba-
sed on morphology, as well as etiology. Morphologically,
the most common type of pediatric cataract is the zonular
cataract, characterized by opacification of a discrete re-
gion of the lens. This type includes nuclear, lamellar, su-
tural, and capsular cataracts [6,10].
Congenital cataracts are one of the most common cau-
ses of treatable blindness in children, particularly in de-
veloping countries [1]. A recent report indicated that in-
fants with bilateral congenital cataract who underwent
early surgery (within 1 month of birth) and received ap-
propriate optical rehabilitation could obtain visual acuity
of better than 0.4 and could even achieve stereopsis [2].
However, because of typically relatively late detection
and diagnosis, the lack of availability of facilities for
*No financial support received from any company or institution, This
study is not presented at any conference or meeting, Authors do not
have any financial interest in any aspect of this study
#Corresponding author.

Strabismus in Cases of Cataract in Pediatric Age Group
20
ininfant anesthesia, and poor compliance with long-term
follow-up, the visual prognosis for infants with conge-
nital cataract in developing countries differs markedly
from that in industrialized nations. Visual loss is primar-
ily attributable to amblyopia, most importantly, to “stimu-
lus-form deprivation amblyopia” with the additional fac-
tor of ocular rivalry in unilateral disease. Thus, improved
understanding of the critical periods of visual develop-
ment has resulted in surgical intervention for dense cata-
racts being deemed necessary within the first 3 months of
life, possibly as early as the first 6 weeks in unilateral
disease. Clinical factors believed to be important to vis-
ual outcome in children include age at diagnosis and sur-
gery, type of refractive correction, type of cataract sur-
gery, compliance with an occlusion regimen, etiology of
the cataract, presence of non-ophthalmic disorders, deve-
lopment of capsular opacity or secondary membrane, and
serious ocular postoperative complications.
2. Materials and Methods
The study was approved by the hospital ethics committee.
This was a prospective hospital-based study at a tertiary
care eye hospital in western India over 20 years, from
January 1992 to April 2012. All pediatric patients (0 - 18)
with cataracts presenting to our department during this
period were enrolled in the study. Primary patient details
and history were documented using a pre-tested online
format. Ocular trauma details were documented with an
online world eye injury registry form.
Gifting Vision was checked according to the American
Academy of Pediatrics vision check protocol. Both eyes
were assessed [19]. Anterior segment examinations were
conducted using a slit lamp bio-microscope. The pupils
were dilated.
Ocular pressure was measured using a Perkin’s hand-
held tonometer. If this was not possible, the pressure was
measured under general anesthesia. This procedure was
omitted for eyes with open globe injuries. The posterior
segment of the eye was evaluated with the help of an
indirect ophthalmoscope, a +20 D lens, and an ultrasound
‘B’ scan if the media was not clear. The surgical tech-
nique was decided based on etiology, cataract morphol-
ogy, and the position of the lens. Surgery was conducted
by the anterior or pars plana route. Anterior route surger-
ies were performed using a phacoemulcifier or manual
suction. Membranectomies and lensectomies were per-
formed using a pneumatic cuter. Intraocular lenses were
not implanted in patients younger than 1.5 years. Chil-
dren below this age underwent lensectomies/membranec-
tomies; secondary implant placement was conducted la-
ter. Patients were rehabilitated using glasses or contact
lenses in-between. For IOL power calculations, we fol-
lowed published guidelines [20,21].
In cases of globe rupture, open globe injury wound
repair was done as a first stage and the cataract was op-
erated on at a second sitting. All steps of the surgical
techniques were documented using a pretested online for-
mat.
All traumatic cataract patients without infection were
treated with systemic corticosteroids. In all patients with
inflammation and membranous cataracts, a primary po-
sterior capsulotomy and anterior vitrectomy were per-
formed.
Postoperative follow-up was performed according to a
pretested online format, including vision, anterior and
posterior segment findings, and intraocular pressure, over
an appropriate follow-up schedule. Glasses were pre-
scribed when the media were clear and the final pre-
scription was at 6 weeks post-operation. Patients under-
went orthoptic evaluations and amblyopic patients were
treated with appropriate patching. Aphakic patients were
rehabilitated using glasses or contact lenses. Patients
were evaluated for stereopsis and contrast sensitivity
using a Titmus vision tester or a Titmus fly test.
Patients developing later cataracts underwent mem-
braneectomies and vitrectomies as required. For children
operated on below the age of 1.5 years, secondary lens
implantation was performed after they reached 2 years of
age.
Data were analysed using the SPSS software (ver. 19.0;
SPSS Inc., Chicago, IL, USA). Univariate parametrical
analyses were used. A P value of <0.05 was considered
to indicate statistical significance.
3. Results
The enrolled patient group consisted of 1331 eyes in
1043 pediatric patients with cataracts. There were 867
(65.1%) males and 464 (34.9%) females (Table 1). The
mean patient age was 4.1 ± 1.06 (range, 0 - 18) years. Of
the cataracts, 605 (45.5%) were traumatic and 726 (54.4%)
were congenital or developmental. Of the eyes, 1145
(86%) had diminished vision and 188 (14.0%) present-
ed with leucokoria. The follow-up period was 1 - 3084
(mean, 117.4) days.
Table 1. Age and gender distributions.
GENDER
AGE AT INTERVENTION
FEMALE MALE
Total
≤1 20 31 51
1 - 3 37 46 83
4 - 5 46 91 137
6 - 10 165 305 470
11 - 18 196 394 590
Total 464 867 1331

Strabismus in Cases of Cataract in Pediatric Age Group 21
We found strabismus in 66 (5%) cases (Tables 2 and
3). We compared strabismus according to age of inter-
vention. A significant association with strabismus was
found in the younger age group (Table 2; P < 0.001).
In the non-traumatic group, eyes were further subdi-
vided into congenital (282, 21.2%), developmental (415,
31.2%), and secondary cataracts (29, 2.2%). According
to the statistical analysis, the demographic factors ana-
lyzed, including socioeconomic status (74.5% were of
lower socioeconomic status) and residence (92% were
from rural areas), had no significant relationship with
final visual acuity. When compared with category, stra-
bismus was less commonly associated with traumatic
cataracts (Table 4; P < 0.001).
Regarding patient entry, 9.2% of the patients had re-
ceived primary treatment prior to reaching our center;
this was not associated with a significant difference in
the final visual outcome (P = 0.2). Of the total patients
enrolled, 26.4% entered via an outreach department, and
71% were self-referred.
Table 2. Strabismus according to age.
SQUINT
AGE AT INTERVENTION NO YES Total
≤1 44 7 51
1 - 3 70 13 83
4 - 5 131 6 137
6 - 10 455 15 470
11 - 18 565 25 590
Total 1265 66 1331
P < 0.001.
Table 3. Amblyopia according to age.
AMBLYOPIA
AGE OF INTERVENTION
−1.00 0.00 Total
≤1 9 42 51
1 - 3 17 66 83
4 - 5 11 126 137
6 - 10 19 451 470
11 - 18 18 572 590
Total 74 1257 1331
P < 0.001.
Table 4. Squint according to cataract etiology.
SQUINT
CATEGORY NO YES Total
TRAUMATIC 595 10 605
NON TRAUMATIC 670 56 726
Total 1265 66 1331
P < 0.001.
Among the injuries, 30% were reported within the first
24 h, 30% were reported within 3 days, and 33.9% were
reported within 1 month. A wooden stick was the most
common object causing eye injury (51.4%). Neither the
injury-causing object (P = 0.3) nor the activity at the time
of injury (P = 0.3) was significantly associated with the
final visual acuity.
A comparison of pre- and post-operative visual acui-
ties showed that treatment significantly improved visual
acuity (Tabl e 5; P < 0.001, Pearson’s χ2 test; P = 0.001,
ANOVA).
We examined unilateral versus bilateral cataracts (Ta-
ble 6; P < 0.001) and found a significant association with
strabismus in bilateral cases.
Sensory nystagmus was present in 250 (18.8%) eyes
and was significantly associated with strabismus (Table
7; P < 0.001).
An intraocular lens was implanted in 1210 cases
(91.1%) and was not significantly associated with stra-
bismus (Table 8; P= 0.137).
When we studied the strabismus, we found that 35
(50.8%) had esotropia, 29 (42%) had exotropia, and five
(7.2%) had vertical strabismus with esotropia or exo-
tropia (Table 9). In total, 36% cases had “special” forms
Table 5. Visual outcome pre–post-patching.
POST PATCH VISION
PRE PATCH
VISION <1/60 1/60 TO
3/60
6/60 TO
6/36
6/24 TO
6/18
Total
<1/60 7 0 0 1 8
1/60 TO 3/602 21 0 0 23
6/60 TO 6/360 4 4 0 8
6/24 TO 6/181 0 2 27 30
6/12 TO 6/90 0 3 1 4
Total 10 25 9 29 73
Table 6. Strabismus compared with laterality.
SQUINT
LATERALITY NO YES Total
UNILATERAL 763 22 785
BILATERAL 502 44 546
Total 1265 66 1331
P < 0.001.
Table 7. Strabismus compared with sensory nystagmus.
SQUINT
SENSORY
NYSTAGMUS NO YES Total
YES 1051 30 1081
NO 214 36 250
Total 1265 66 1331
P < 0.001.

Strabismus in Cases of Cataract in Pediatric Age Group
22
Table 8. Strabismus compared with the presence of IOL.
SQUINT
IOL NO YES Total
YES 1153 57 1210
NO 112 9 121
Total 1265 66 1331
P = 0.137.
Table 9. Type of strabismus.
TYPE NUMBER (n) PERCENT (%)
ESOTROPIA 35 50.8
VERTICAL 5 7.2
EXOTROPIA 29 42.0
Total 69 100.0
of strabismus, like A pattern, V pattern, or dissociated ver-
tical deviation. In cases with strabismus, 37 (53.6%) had
sensory nystagmus and 56 (81.2%) had amblyopia.
4. Discussion
The enrolled patient group consisted of 1331 eyes in 815
pediatric patients with cataracts. There were 867 (65.1%)
males and 464 (34.9%) females (Table 2). The mean
patient age was 4.1 ± 1.06 (range, 0 - 18) years. Of the
cataracts, 605 (45.5%) were traumatic and 726 (54.4%)
were congenital or developmental. The mean patient age
was 4.1 ± 1.6 years. The mean age in another report was
7.1 [22]. Age at intervention had a significant effect on
visual outcome (Table 2). Other investigators have re-
ported similar findings [23].
The incidence of traumatic cataracts in children was
higher than that reported previously [24]. In a compare-
son of the traumatic and non-traumatic groups, the group
with traumatic cataracts had a significantly lower inci-
dence of strabismus, likely attributable to the more fully
developed visual system in children in traumatic cases.
Spanou et al. reported strabismus in 23% and Magli et al.
reported a 34% incidence of strabismus in contrast to
only 5% in our study [25,26], perhaps because of the
larger number of traumatic cataracts. Regarding unila-
teral and bilateral cases, we found a higher incidence of
strabismus in bilateral cataracts in contrast to another re-
port [25].
A retrospective study of the outcome of surgery for ca-
taracts in the pediatric age group has several limitations.
Although we believe that all patients included in the stu-
dy had congenital, developmental, or traumatic lens opa-
cities, not all patients were seen and followed by us from
the time of birth. In particular, some patients with lamel-
lar cataracts were not seen by us until they were several
years old.
Treatment of strabismic amblyopia following bilateral
congenital cataract surgery is useful, although the ocular
misalignment is sometimes hard to identify, and the am-
blyopia may be profound by the time it is recognized [10,
27]. Deprivational amblyopia due to asymmetry of cata-
racts from the outset is very difficult to reverse, similar to
the situation in patients with monocular congenital cata-
racts. An early start of treatment would seem to be the
only hope of success in these asymmetric cases [10].
In conclusion, the incidence of strabismus in cases of
pediatric cataract was only 5%, was more common in the
non-traumatic group and bilateral cases in the younger
age group. Orthoptic treatment had a significant effect on
visual outcome.
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