Symmetric vs Asymmetric BLR Recession in Management of Basic IXT With Ocular Dominance

Symmetric Versus Asymmetric Bilateral Lateral Rectus Recession in Management of Basic Intermittent Exotropia With Ocular Dominance

The study aims to investigate ocular motor and sensory outcomes of two different strategies of lateral rectus recession; symmetric and asymmetric, in management of basic type intermittent exotropia with ocular dominance.

Surgical management of basic -type intermittent exotropia with a dominant eye is controversial. Some surgeons do traditional symmetrical bilateral lateral rectus recession, while other perform unilateral recess-resect procedure in the non-dominant eye. The aim of this study is to investigate the effect of two different strategies of bilateral lateral rectus recession; symmetrical recession in which the amount of recession is equally divided between both eyes, and asymmetrical recession, in which the amount of recession is 2mm more in the non-dominant. Outcome measures include ocular deviation at distant and near fixation, sensory status and complications.

The amount of bilateral lateral rectus recession is asymmetrically divided between both eyes, with 2mm more recession in the non-dominant eye.

Symmetric bilateral lateral rectus muscle recession involves equal recession of both lateral rectus muscles. Asymmetric bilateral lateral rectus muscle recession involves recession of the lateral rectus muscle by 2mm more in the non-dominant eye.

ocular alignment in prism diopter (PD) at distant fixation (6 meter) is measured using alternate prism and cover test (APCT) while patient wears refractive correction.

ocular alignment in prism diopter (PD) at near fixation (1/3 meter) is measured using alternate prism and cover test (APCT) while patient wears refractive correction.

ocular sensory status (fusion and stereopsis). Fusion is assessed using Worth 4-dot test, and is documented as present (+ve) or absent (-ve). Fusion is assessed using Titmus fly test and is recorded as seconds of arc.

During the follow up period. postoperative surgical complications, such as over correction (consecutive esotropia) and under correction (recurrent exotropia), are recorded.

Inclusion Criteria: Basic-type intermittent exotropia Simulated distant-type intermittent exotropia Exclusion Criteria: Alternating basic-type intermittent exotropia (no ocular dominance) Distant-type intermittent exotropia Convergence-insufficiency type intermittent exotropia Constant exotropia Sensory exotropia Deep amblyopia Paralytic or restrictive exotropia Previous extraocular muscle surgery