Anomalies Of Convergence

Anomalies Of Convergence
Mr. Mahendra Singh
PhD (Scholar) M.Optom, FLVPEI (Hyd)
Assistant Professor and consultant Optometrist.
CL Gupta Eye Institute. UP India

Mr.Mahendra Singh
PhD (Scholar) M.Optom,
FLVPEI (Hyd)
Assistant Professor and
consultant Optometrist.
CL Gupta Eye Institute. UP India

Defination
Disjugate movement of the two visual axis
towards the midline ( to keep the object of
fixation as one fused image).

Stimulus
Sense of proximity of object
Involuntary appreciation of diplopia and
effort to maintain BSV.
Stimulus to accommodaion

Measurement
Meter angle
By placing prisms of increasing Base out in front
of both eye, which will produce movement of
adduction in order to maintain binocularly
Push-Up test
By RAF-Gauge
By Livingston Binocular Gauge
By Synoptophore

Convergence Insufficiency:-
 It is the inability to obtain &/ or maintain adequate binocular
convergence for any length of time without under effort.
Convergence Paralysis:-
 It refers to a total lack of ability to overcome any amount of
base-out prism.
Convergence Spasm:-
 It is usually associated with spasm of accommodation

Convergence Insufficiency
Etiology:-
 Primary:-
 It is due to wide interpupillary distance & delayed or
inadequate functional development.
 General debility, Psychological instability, over work &
worry may be the precipitating factors.
 Refractive Error:-
 It may be associated with uncorrected high
hypermetropia & myopia.
 High hypermetropia ( more than 5D ) usually makes no
accommodation & thus there is deficient accommodative
convergence.

 Myopes may not need accommodation thus lack
accommodative convergence.
 Muscular Imbalance:-
 Extraocular muscular imbalances in the form of
exophoria, intermittent exophoria, if neglected for a long
time may be associated with convergence insufficiency.

Diagnosis
Diagnosis of convergence insufficiency is
confirmed by:-
 Near point of Convergence
 Convergence insufficiency is said to be exist if NPC is
more than 10cm from the base line.
 Synoptophore
 When measured on synoptophore the convergence is said
to exist if there is difficulty in attaining 30° of
convergence.
 Prisms
 Prism convergence is low but prism divergence is
normal.

Treatment
Optical Treatment:-
• Proper refraction should be done
• Myopes are give full correction & hypermetropes
are under corrected to stimulate their
accommodation which will simultaneously
stimulate convergence
Orthoptic Treatment:-
• Main aim of orthoptic exercise is to improve the
binocular convergence & increase the amplitude of
fusional convergence.

Prismotherapy:-
 When all the exhaustive exercise fails then
prismotherapy may be tried to relieve symptoms
 Base-in prism reading glasses or bifocal with prism
in the lower segment are useful as relieving prism.
Surgical treatment:-
 As a last resort, medial rectus resection can be
performed in one or both eyes.

Convergence Paralysis
Etiology:-
 Convergence paralysis occurs secondary to some
organic disease of the barin. The organic brain lesions
reported to be associated with this condition as
follows.,
 Head injury
 Encephalitis
 Disceminated sclerosis
 Tabes dorsalis
 Narcolepsy
 Tumours

Diagnosis:-
 Evidence of intracranial disease.
 History of sudden onset of crossed horizontal
diplopia at near fixation.

Treatment
 Base-in prisms are prescribed at near to alleviate the
diplopia at near.
 Plus lenses with base-in prisms may be required in
patient having weakness of accommodation
 Occlusion of one eye at near may be indicated in
comfortable single binocular vision
 Eye muscle surgery is contraindicated in this
condition.

Convergence Spasm
Etiology:-
 Functional cause:-
 It occurs in patient with hysteria or neurosis
 Organic cause:-
 Rarely convergence spasm may be secondary to
some underlying organic lesion.
 It has been reported to occur after head trauma,
encephalitis, tabes, pituitary adenomas & posterior
fossa neurofibroma.

Treatment
 Prolonged atropinization with plus lenses in lower
segment of bifocals for near work may be required
to break the cycle.
 Alternate monocular occlusion mat be considered as
an alternative to atropinization.

Simple explanation of C.I
This is condition in which the muscles of
eye responsible for convergence (turning
the eyes in) appear to be weak, at least
relative to the muscle responsible for
divergence(turning the eyes out).
How ever the patient’s eyes remain straight
in all field of gaze.

Detailed explanation of C.I.
Convergence insufficiency is a common condition
that is characterized by person’s inability to
maintain proper binocular eye alignment on
objects as they approach from distance to near.
There is typically an exophoria or intermittent
exotropia near, a receded near point of
convergence, reduced positive fusional
convergence amplitudes/accommodation(AC/A)
ratio

Causes
The causes of convergence insufficiency are
not completely clear .
A connection has been made between
accommodative insufficiency and
convergence insufficiency.
A significant exophoria at near with
inadequate fusional convergence appears to
be the primary underlying problem.

Symptoms
The symptoms of CI are associated directly
with reading or other close work visual
demands.
Many patients with objectively measured CI
may not complain of symptoms.
This usually occurs because of suppression
of non-fixating eye or avoidance of near
vision tasks.

Contd…
The most common symptoms associated with CI
are..,
 Asthenopia (eyestrain)
 Headache
 Diplopia
 Blurred vision
 Moving of print while reading
 Orbital pain
 Abnormal postural adaptation

Aggravated by
Symptoms are aggravated by illness,lacks
of sleep,anxiety and prolonged near work.
The frequency of symptoms may increase
with age as patients ability to compensate
for their relative divergent binocular
alignment decreases with time.

Asthenopia & headache
This is commonly occurs due to the
sustained increased effort required to
increase fusional convg.
AI is often associated with CI abd
symptoms of asthenopia and headache.
This occurs as patient tries to eliminate near
vision diplopia by increasing
accommodative effort.

Diplopia
The diplopia that manifests in some patients
with CI may present as 2 distinct images or
just overlap of 2 images.
Some patients with CI do not have
symptoms of diplopia despite an obvious
exodeviation at near, this probably occurs
because of supression of the nonfixationg
eye.

Blurred vision
Patient with uncorrected hyperopia in
excess of 5.00 D may produce little or no
accommodative effort at near. This lack of
accommodation efforts results in blurred
near image.
Efforts to primarily increase convergence
through stimulation of accommodative
convergence to eliminate diplopia can cause
blurr vision.

Moving of print
This occurs because of fluctuating binocular
alignment relative to reading material.
This usually occurs when the patient tries to
bring in enough fusional convergence to
maintain binocular vision.

Fatigue, frequent loss of place
Frank binocular diplopia associated with
near point tasks are among the symptoms
associated with this condition.
Patients typically present as teenagers or in
early adulthood, complaining of gradually
worsening eyestrain, periocular, headache,
blurred vision after brief period of reading.

Close up work
Many patients with this disorder have vocational
and/or avocational visual demands that require
prolonged close-up work .
The most common presentation encountered by a
clinician is that of a high school or college student
who develops symptoms when excessive demands
are placed on the visual system during extended
periods of studying.

Eye contact
When the two eye fail to work together as
an effective team, performance in many
areas can suffer
Reading, sports, depth perception, eye
contact, etc.

Types of CI
Primary or Idiopathic
Secondary to primary divergenct
strabismussecondary to vertical muscle
defect
Refractive
Systemic
Presbyopic
Post-operative (surgically induced)

Primary CI
This is not associated with any obvious
exophoria either for distance or for near,
that is not more than 3-4 prism diopters foe
distance or 8 prism diopters for near
In some cases there are predisposing factors
such, as overwork, worry or some recent
illness .

Secondary to primary div.
strabismus
This is especially liable to occur in certain
cases of primary div. Strabismus of the
divergence excess bye if traetment has been
neglected until later life.
Management:-
 Operation is usually needed to rectify the
defect.

Secondary to vertical strabismus
In these cases it is essential initially to
overcome the vertical muscle imbalance by
operation.
Management:-
 Orthoptics treatment is needed.

Refractive errors
In order to reap the benefit of convg. A sharp and
clearly defined image must be formed upon each
foveal area.
If this is prevented on account of an uncorrected
refractive error, a relative defect pf convg. Will
appear to be present.
CI is also evident in the patients who have
habitually worn too full a plus spherical
correction.

Contd…
Management:-
 When the refractive error is corrected by means
of suitable lenses the improved near point of
convg. Will be observed.

Systemic CI
Patient in this group are usually the victims
of some general ill-health either bodily or
mental.
Management:-
 Orthoptics treatment
 Apart from orthoptics treatment general health
of the patient should be improved.

Presbyopia
The near point of convg. Recedes as
accommodation decreases with age, and
there tends to develop exopphoria for near
fixation.
Management:-
 Adequate correction for the presbyopia and
simple convg. Exercises are usually all that is
needed in the treatment of this condition.

Post operative ( surgically
induced)
This may occur as a result of an over-liberal
recession of one or both of the medial recti
Or of an over-liberal resection of one or
both of lateral recti.
Management:-
 The condition can only be remedied by
corrective surgical treatment.

Diagnostic factors
High exophoria at near
High AC/A ratio
Receded near-point of convergence
Low fusional vergence ranges
Exo-fixation diparity with steep forced
vergence slope

Goals of treatment
Normalize the near-point of convergence
Normalize fusional vergence ranges
Eliminate suppression
Mormalize associated deficiencies in ocular
motor control and accommodation
Normalize accommodation/convergence
Normalize depth judgement and/or
stereopsis

Treatment
Medical care
Surgical care
Follow-up care

Medical care
Orthoptics and vision therapy
 Near point of convergence exercises:-
 Other forms of convergence training:-
 Base-in prisms for near only:-

Near point of convg. exercise
An accommodative target, such as point of
pencil is placed remote to the patient’s near
point of convg. & gradually brought
towards the tip of the nose with the patient
converging to avoid diplopia.
Just before there is a break in fusion, the
patient holds fixation on the target for 10
seconds.

Contd…
This so called push up is repeated 10 times,
2-4 times a day, until the patient is able to
hold fixation to the tip of the nose.
The exercise can be tapered and then used
on an as-needed basis when the patient
noticesa recurrence of symptoms.

Other forms of training
Based-out prism reading and stereogram
cards may be used to improve fusional
convergence.
New, affordable computerized fusional
vergence training program are also
available. These self-placed programs can
be used on a personal computer in the
patient’s home.

Base-in prisms for near only
These prisms can be ground into a separate
pair of reading glasses, or fresnel membrane
prisms can be fitted over reading segment of
the patient’s bifocals.

Surgical care
The decision to proceed with surgery should
be made with caution and only after all
orthoptics efforts have failed.
Bilateral medial rectus resections are
usually the most effective operation for this
condition

Complications
The untreated condition often can make
both work and recreational near vision tasks
difficult.

Prognosis
In most cases, if the patient is motivated,
the prognosis for successful treatment of
this condition is excellent.
Patient education:-
 Patient should be made aware that CI is a fairly
common condition and that treatment is very
effective.

Follow-up care
At the conclusion of the active treatment
regimen, periodic evaluations should be
provided at appropriate intervals.
Therapeutic lenses may be prescribed at the
conclusion of vision therapy for
maintenance of long-term stability

Anomalies Of Convergence

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