Many studies have been conducted over the last few decades to assess the need for cycloplegia
in assessing refractive errors. Plenty of research on pediatric populations has demonstrated
that a lack of cycloplegia may contribute to an overestimation of myopia prevalence or
substantial mistakes in estimating the prevalence of emmetropia and hyperopia. (1,2) The
amount of refractive error varies by individual, as well as the type of cycloplegic
refractive error. (3) As a result, there is no reliable method for adjusting non-cycloplegic
refractions to approximate cycloplegic refractions. Consideration should be given to the type
of cycloplegic agent to be used, preferred dosing, optimal methods of instillation,
indications for use, and potential side effects. Despite the fact that the benefits of a
cycloplegic examination are undeniable, there is still some confusion and various practice
methods when it comes to cycloplegic exams. (4) Although atropine is the most potent
cycloplegic agent currently available in clinical practice, its long duration of action (up
to 12 days) and well-known side effects have shifted clinical practice toward cyclopentolate
use. Cyclopentolate has been shown to provide effective cycloplegia, even in patients with
moderate to severe hyperopia, with a relatively short duration of action (up to 24 hours) and
fewer side effects. Thus, since its introduction in 1951, cyclopentolate has largely replaced
atropine as the standard of care for pediatric cycloplegic examination. (4,5,6) Nevertheless,
numerous adverse effects of cyclopentolate for children have been observed, including dry
mouth and skin, tachycardia, fever, hallucinations, delirium, restlessness, seizures, ataxia,
acute midbrain hemorrhage, and even death. (7,8,9) Many studies compared cyclopentolate to
tropicamide for cycloplegia. (10, 11, 12) Tropicamide, unlike cyclopentolate, is a
cycloplegic with a rapid onset and a short duration of action lasting up to 6 hours. In
addition, fewer side effects have been reported when compared to cyclopentolate. (3,11)
According to the literature, cyclopentolate may cause +0.175 to +0.39 D more hyperopia than
tropicamide, which is clinically insignificant. (10,11,13) Furthermore, it has been
discovered that there is a strong correlation between the time spent waiting to complete the
exam and patient satisfaction levels, so reducing the waiting time clearly increases
satisfaction levels. (14, 15) Esotropia is a convergent misalignment of the visual axes.
Esotropia can be categorized in a variety of ways, usually based on age of onset or
underlying causes: Infantile esotropia or acquired esotropia or accommodative esotropia,
either normal accommodative convergence/accommodation (AC/A) ratio or high AC/A ratio or
partially accommodative esotropia or Nonaccommodative esotropia, and Sensory esotropia. (16)
Prevalence estimates of strabismus range from 0.8% to 6.8% in different populations. In the
United States, esotropia and exotropia have similar prevalence rates, whereas in Ireland
esotropia has been reported five times more frequently than exotropia, and in Australia
esotropia has been reported to be twice as frequent as exotropia. (17) The prevalence of
esotropia in children increases with age (e.g., higher prevalence at 4 to 6 years compared
with 6 to 11 months), moderate anisometropia, and moderate amounts of hyperopia. (18) The
potential benefits of treatment for esotropia include promoting binocular vision and
improving visual function in each eye. (19) If binocularity is achieved, the number of
surgical procedures over a lifetime and overall cost to society may be reduced. (20) Fusion
and stereopsis are necessary for some careers and may be useful in sports such as baseball
and activities such as needlepoint and watching 3D movies. (21) The appearance of crossed
eyes may reduce employment opportunities because of stigma and bias. (22) In addition,
binocular alignment is important for the development of a positive self-image and enhances
social interactions by normalizing appearance as well as eye contact. (23) In one study,
children aged 5 years and older expressed a negative feeling about dolls that had been
altered to be esotropic or exotropic. (24) In another study, elementary school teachers rated
personal characteristics of children with esotropia and exotropia more negatively than
orthotropic children. (25) In a sample of children enrolled in the Multi-ethnic Pediatric Eye
Disease Study, strabismus was associated with a decreased general health-related quality of
life in preschool children, based on the parents' proxy reporting. (26) Adequate cycloplegia
is necessary for accurate retinoscopy in children because of their increased accommodative
tone compared with adults. The aim of this randomized clinical trial (RCT) is to explore the
cycloplegic effect of tropicamide versus cyclopentolate in refracting pediatric subjects with
esotropia.