ABSTRACT
Convergence excess esotropia is a condition characterized by an esotropia which is greater for near fixation than for distance fixation after full hypermetropic correction with a single focus lens. Convergence excess esotropia may be classified according to the AC/A ratio into two subtypes: accommodative type and non-accommodative type. Bifocal glasses are a suitable option for the management of patients with a high AC/A ratio and for the hypoaccommodative type. However, the overall success rate with bifocals is still low even in selected patients. Surgery is often eventually needed for most patients with convergence excess esotropia. Surgical options that do not directly address the variability of the angle of deviation entail medial rectus recession with the target angle based on the distance deviation, the near deviation, an augmented formula based on an intermediate angle, or on a prism adaptation test. Surgical options that directly address the variability of the angle include partial myotomy, medial rectus muscle posterior scleral fixation with or without recession, pulley fixation, slanting recession, Y-splitting, or combined recession-resection of the medial rectus muscle. The review article summarizes the surgical outcome of these strategies and suggests an algorithm for the management of patients with convergence excess esotropia.
Methods of literature search
Literature search was conducted in January 2022 on theMEDLINE database using a combination of the search terms: “convergence excess esotropia;” “distance-near disparity” and “esotropia;” “near-distance disparity” and “esotropia;” “high AC/A;” “near esotropia.” There was no restriction to date of publication, or to language. The search yielded a total of 3569 hits. The abstracts were reviewed for articles of relevance, and whenever there was any doubt to the relevance of the reference, the reference was read in full text. In addition, some papers that were not identified by this literature search were identified by other means such as the reference list of the manuscripts. Articles in any language other than English were translated. Data were extracted from the included studies whenever necessary by two reviewers (AA and JG). Because of the scarcity (or absence) of evidence-based research on convergence excess, all papers were included in this narrative review regardless of the level of evidence.
Abbreviations
AC/A | = | accommodative convergence/accommodation ratio |
ACE | = | accommodative convergence excess |
BMR | = | bilateral medial rectus muscle recession |
CA/C | = | convergence accommodation/convergence ratio |
D | = | diopters |
Dcc | = | distance angle with correction |
DND | = | distance-near disparity |
ET | = | esotropia |
F/U | = | follow-up |
IO | = | inferior oblique |
LRR | = | lateral rectus muscle resection |
mo | = | months |
NACE | = | non-accommodative convergence excess |
NA | = | not available |
Ncc | = | near angle with correction |
NPA | = | near point of accommodation |
Nsc | = | near angle without correction |
PAT | = | prism adaptation test |
PD | = | prism diopters |
preop | = | preoperative |
PD,RR | = | recession-resection |
UMR | = | unilateral medial rectus muscle recession |
X | = | exophoria |
X(T) | = | intermittent exotropia |
Authors’ contributions
Ahmed Awadein: Conceptualization, Methodology, Writing, Reviewing, and Editing Jylan Gouda.: Data curation, Writing, and Original draft preparation. Hala Elhilali: Reviewing and Editing. Kyle Arnoldi: Reviewing, Editing, and Supervision
Disclosure statement
No potential conflict of interest was reported by the author(s).