Esotropia is a common clinical problem reported among the patients
visiting outpatient department of hospitals [1]. A meta-analysis pertinent to
esotropia revealed its prevalence to be about 0.77% [2]. It is the commonest
type of strabismus that has considerably been reported among children [3]. The
prevalence of strabismus across the globe is 0.5-5% [4]. While associated
convergent squint in Pakistan is delineated to be 2.5-2.75% [5]. However, this
eye problem is prevalent among 2-6% of the children [6]. Essential infantile
esotropia has significantly been proclaimed as childhood strabismus [7].
Comprehensive demographic, medical and family history concomitant with detailed
clinical assessment can help a great deal in managing such cases [8]. Although
idiopathic, but children with positive family history of esotropia have
increased likelihood to present with this visual defect [9]. Infantile
esotropia is to be treated surgically during infancy. Furthermore, children
with constant infantile esotropia should now preferably be subjected to surgery
at or before 10 months of age [10]. On the other hand, esotropia detected among
children in connection with amblyopia can sufficiently be rectified by using
glasses and other conservative measures [11]. A study carried out in a public
sector hospital of Karachi revealed that esotropia constituted relatively the
most frequently diagnosed type (58%) of strabismus among 6-15 years old
children5. Likewise, a study done among children of al-Ibrahim eye hospital
Karachi reflected relatively higher frequency of esotropia (66.7%) among
strabismic children with mainstream having this problem congenitally [12].
Although strabismus has sufficiently been researched out but studies
specifically on esotropia are quite meagre. The present study is therefore
intended to determine the effect of convex lens on the magnitude of esotropia
among patients visiting Ophthalmology department of Holy Family Hospital,
Rawalpindi. This research on detecting the usefulness of convex lens on the
magnitude of esotropia would surely prove helpful to our ophthalmologists and
optometrists in managing and guiding the esotropic cases in true spirit for
improving their visual defects and refractive errors [13].
Subjects and Methods
A
cross-sectional descriptive study was carried out among esotropic cases
presenting in Out Patient Department (OPD) of Holy Family Hospital Rawalpindi
from 15th June 2021 to 15th January 2022. Patient’s upto 30 years of age not
suffering from any mental illness or retardation were enrolled in the study by
consecutive non-probability sampling. Self-designed structured orthoptic
proforma was used to collect the data pertinent to demographics, history of
presenting illness, past history of wearing glasses, family history, and
surgical treatment of squint, orthoptic assessment, patching technique and
refractive status. Orthoptic assessment as well as visual acuity assessment was
carried out by means of Hirschberg’s test reflex, Cover test, prism cover test,
extraocular eye movements, abnormal head posture checkup and cycloplegic
refraction. This article is based on thesis that was composed in partial
fulfillment of BSc (Hons) Optometry & Orthoptics requirement. Data analysis
was done by using SPSS version 25.0 and Microsoft Excel 2016. Descriptive
statistics were applied.
Results
Of
the total 40 esotropic patients participating in the study, 67.5% and 32.5%
were females and males respectively. Mean age of the patients was 19.6 ± 7.4
years. Most (45%) of our study subjects were upto 20 years of age as depicted
below in (Figure 1). Majority
(52.5%) had unilateral squint. There were 32.5% patients who developed
strabismus due to amblyopia and 67.5% patients were non-amblyopic. Use of
convex lens was found to be considerably effective in squint improvement among
82.5% of the cases as revealed below in (Figure 2).
Discussion
Esotropia
has been acknowledged with extreme racial differences. Obvious ocular
deviations are determined to be about 3.3% and 2.1% among white and black
American races respectively. In current study, about 67.5% of the patients
presenting with esotropia were females with highest propensity of up to 20
years old patients. Likewise a hospital based study carried out in Nigeria
revealed predominance (55.2%) of strabismus among females and majority of them
was up to 9 years old [14].
Figure 1: Age of study participants.
Figure
2:
Use of convex lens.
This
age-based difference among strabismic cases might be due to the fact that
Nigerian study was specifically on pediatric patients while our study was
encompassing the cases who presented in Ophthalmology department of a tertiary
care hospital. Another study done by Qanat AS et al among pediatric population
to scrutinize the types of strabismus revealed esotropia as the maximally
prevailing type in equal magnitude among both genders [15]. Likewise, another
study by among pediatric population in a tertiary care hospital of Karachi
discovered esotropia as the most commonly prevailing ophthalmic disorder [16].
However, , exotropia was determined to 7 times more prevalent than that of
esotropia among Singaporean Chinese children up to 6 years of age with no
gender discrimination [17]. Reserch on gender based variations in the
propensity of esotropia can serve as a guide to concerned health authorities
for planning the relevant healthcare preventive measures. Amblyopia and squint
in the light of recent studies are known as predominant visual defects despite
the correction of visual acuity with glasses rather in absence of any other
ocular or neuronal flaws [18]. In our study, 32.5% of the patients developed
strabismus due to amblyopia. A study carried out by Shafique MM et al among
patients visting Ophthalmology department of Sir Ganga Ram Hospital Lahore
concluded that early management of strabismic amblyopia during initial stage of
life can protect a child from long term visual disability [19]. Numerous
studies have also shown amblyopia as the commonest cause of strabismus among
people; however, these both visual defects have probability to occur
simultaneously. Therefore, prompt treatment of either disorders is deemed
necessary in order to get rid of resultant complications [20]. About 82.5% of
our esotropic cases showed improvement in strabismus with use of convex lens.
On reviewing the conservative management of concomitant strabismus by Joe
Smith, use of convex lens by estropic cases was recommended to improve their
visual acuity and binocular single vision [21]. There is scarce supporting
evidence pertinent to effectiveness of orthoptic exercises among estoropic
relative to exotropic cases [22]. Use of hypermetropic spectacles also led to
correction of convergent squint after constant use of 3 months among children
who were subjected to long-term follow up after thorough diagnosis of this
visual error [23]. Treatment by an ophthalmologist or optometrist is proven to
be substantially beneficial at intitial stage with maximal recovery [24]. In
addition to prompt diagnosis and intervention, consistency in treatement is of
paramount significance in complete cure of the ophthalmic disorders. Further
studies on correction of amblyopia with use of hyeropic glasses can also be
useful in proving the efficacy of corrective lenses.
Conclusion and Recommendations
Females
in our community are more likely to present with esotropia and use of hyperopic
glasses by esotropic patients assisted to improve their ocular alignment. Early
presentation to healthcare and proper management helps to restore vision and
minimize the risk of developing amblyopia.
Limitations of Study
Short
study period, small sample size and less follow up of the cases were the
shortcomings of this study.
Conflict of Interest
None
to declare