Abstract:
There are conflicting and confusing ideas in
literature on the different types of accommodative
and vergence anomalies as different
authors turn to classify them differently. This
paper sought to review literature on the different
classifications and types of nonstrabismic
binocular vision anomalies and harmonize
these classifications. Search engines, namely
Google scholar, Medline, Cinahl and Francis
databases, were used to review literature on
the classification of accommodative and vergence
dysfunctions using keywords like binocular
vision dysfunctions, classification of nonstrabismic
binocular vision disorders or anomalies,
accommodative disorders/anomalies classification
and vergence disorders/anomalies
classifications, and included works that
described these anomalies. Nonstrabismic
binocular vision anomalies are classified as
accommodative and vergence anomalies.
There are three different major types of
accommodative anomalies, namely accommodative
insufficiency, accommodative infacility
(accommodative inertia), and accommodative
excess (accommodative spasm), and
seven different types of vergence anomalies
(convergence insufficiency, convergence
excess, divergence insufficiency, divergence
excess, basic esophoria, basic exophoria and
fusional vergence dysfunctions), which are
functional in origin. Functionally, there is a
commonly reported interaction between
accommodative and convergence insufficiency
referred to as pseudoconvergence insufficiency.
Accommodative paralysis (subtype of
accommodative insufficiency) and vergence
anomalies – i.e., convergence paralysis, convergence
spasm and divergence paralysis – are
non-functional in origin with underlying systemic
disease etiologies. Systemic convergence
insufficiency, associated with subnormal
accommodation, is a non-functional interaction
between the accommodative and convergence
insufficiency. The classification of
nonstrabismic binocular vision anomalies is
based on the description of the clinical signs
and the underlying etiology either functional
or non-functional in origin. Proper diagnosis and management involves investigation of the
underlying etiology in addition to the battery of
binocular vision test procedures.
