Abstract:
There are conflicting and confusing ideas in
literature on the different types of accommoda-
tive and vergence anomalies as different
authors turn to classify them differently. This
paper sought to review literature on the differ-
ent 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 ver-
gence dysfunctions using keywords like binoc-
ular vision dysfunctions, classification of non-
strabismic binocular vision disorders or anom-
alies, accommodative disorders/anomalies clas-
sification 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 accom-
modative insufficiency, accommodative infa-
cility (accommodative inertia), and accom-
modative 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 insufficien-
cy. Accommodative paralysis (subtype of
accommodative insufficiency) and vergence
anomalies – i.e., convergence paralysis, con-
vergence spasm and divergence paralysis – are
non-functional in origin with underlying sys-
temic disease etiologies. Systemic conver-
gence insufficiency, associated with subnor-
mal accommodation, is a non-functional inter-
action between the accommodative and con-
vergence 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.
