Part-time Patch Therapy for Treatment of Intermittent Exotropia

Study Overview
=================
Brief Summary
-----------------
Intermittent exotropia is the most common type of exotropia in children. Treatment options are surgical and non surgical. Nonsurgical management include Correction of refractive errors, Active orthoptic treatments, Prisms and Occlusion therapy. Benefits of patch therapy are limiting suppression, reducing the frequency and amplitude of the deviation, changing the nature of the deviation (from constant to intermittent exotropia or from intermittent exotropia to exophoria), however, there is a concern that occlusion of the eyes may cause fusion failure and worsen deviation control. According to a few number of studies and controversy among the results of investigations, the investigators designed this randomized clinical trial study to determine the effect of partial patch therapy on the deviation control of children with intermittent exotropia.

Official Title
-----------------
A Randomized Clinical Trial of Part-time Patching Therapy on Improvement of Deviation Control in 3 to 8 Year-old Children With Intermittent Exotropia

Conditions
-----------------
Intermittent Exotropia

Intervention / Treatment
-----------------
* Other: patch therapy


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Intermittent distance exotropia or constant distance exotropia at least 15Δ and intermittent near exotropia or exophoria Exclusion Criteria: No child's cooperation in evaluation of deviation control and regular visits for follow-up examinations Anisometropia more than 1.50 D, hypermetropia more than 3.50 D, and myopia more than 4.50 D on cyclorefraction History of previous treatments including eye occlusion, minus therapy, and strabismus surgery Any eye and systemic diseases other than strabismus including neurologic diseases and developmental delay.

Ages Eligible for Study
-----------------
Minimum Age: 3 Years
Maximum Age: 8 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: the experimental group will be treated with part time patch therapy and control group will be observed without any treatment.
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: patch therapy<br>The eyes are alternatively patched for 2 hours a day in cases without a dominant eye while in cases with dominancy, the dominant eye is patched five days a week and the non-dominant eye is patched two days a week. | Other: patch therapy<br>* The eyes are alternatively patched for 2 hours a day in cases without a dominant eye while in cases with dominancy, the dominant eye is patched five days a week and the non-dominant eye is patched two days a week<br>|
| No Intervention: Control<br>no intervention will be done | |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 3-point scale Deviation Control | the ability of the child to control his/her deviation at far and near was assessed based on an office control 3-point scale : Children are categorized according to the office control 3-point scale into three control groups: good, fair, and poor. Good control: deviation occurs only during covering the eye and fusion is quickly established after removing the cover without blinking and re-fixation. Fair control: deviation occurs only during covering the eye and fusion is established after removing cover by blinking or re-fixation does happen. Poor control: deviation occurs spontaneously without covering and fusion hardly happens with too much effort and after a long time. | 3 months after treatment | 
| 3-point scale Deviation Control | the ability of the child to control his/her deviation at far and near was assessed based on an office control 3-point scale : Children are categorized according to the office control 3-point scale into three control groups: good, fair, and poor. Good control: deviation occurs only during covering the eye and fusion is quickly established after removing the cover without blinking and re-fixation. Fair control: deviation occurs only during covering the eye and fusion is established after removing cover by blinking or re-fixation does happen. Poor control: deviation occurs spontaneously without covering and fusion hardly happens with too much effort and after a long time. | 6 months after treatent | 
| 6-point scale Deviation Control | the ability of the child to control his/her deviation at far and near was assessed based on the office control 6-point scale: Children are classified according to the office control 6-point scale into six groups of 0 to 5. In this classification, exotropia is ranked after 30 seconds of observation: constant exotropia is ranked 5th, exotropia in more than 50% of the observing time is ranked 4th, and exotropia in less than 50% of the observing time is ranked 3rd. If exotropia is not seen in 30 seconds, the classification is made based on the speed of deviation control and fusion return 10 seconds after covering the eyes: back of fusion in more than 5 seconds is ranked 2nd, fusion return between 1 and 5 seconds ranked 1st, and fusion return in less than 1 second is ranked 0. | 3 months after treatment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Near stereopsis | Stereo acuity is measured at 40 cm using the Titmus test | at the time of enrollment, 3 month later and 6 month later | 
| Fusion | fusion at far & near are measured using the Worth 4-dot test. The Worth 4-dot test is used at 50 cm and 6 m for evaluating central and peripheral suppression. | at the time of enrollment, 3 month later and 6 month later |