F.ALIASGER

Lecturer, SPIO ( a unit of Dr. Agarwal’s eye hospital , chennai )

Fakhruddin Aliasger

Bagolini’s striated glasses

Worth’s four dot test

Synaptophore

Prism Bar Cover Test(PBCT)

After image test

Progressive prism adaptation test(PPAT)

Fakhruddin Aliasger

Bagolini’s lenses are lens with fine grating of lines placed at 135 and 45 degrees in right and left eye

In unilateral strabismus if the lens before the deviated eye produces a streak that appears to go through the spot of light it indicates harmonious ARC

If the lens before the deviated eye produces a streak that does not go through the spot of light then it indicates presence of UNHARC

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Harmonious ARC Homonymous diplopia

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In the Worth 4-dot test, a red glass is worn in front of 1 eye and a green glass in front of the other

The Worth 4-dot test can produce a diplopic response in non-suppression heterotropicNRC and either a diplopic or a fusion response in ARC

As mentioned earlier, this test must be performed in conjunction with cover testing

Fakhruddin Aliasger

Fakhruddin Aliasger

Fakhruddin Aliasger

Make the patient sit on the synaptophore

Alternate flashing is done infront of both the eye and then type of deviation is noted

Then objectively angle of deviation is noted

Objective angle of deviation is neutralized by moving the arms inward or outwards

The angle of deviation is known as objective angle of deviation

Fakhruddin Aliasger

With SMP slide inside the tube the patient is asked whether slides are percivedsimultaneously as single object

If slides are not percived simultaneously then the patient is asked to move the arm such that slides are percieved as single object

The angle at which patient percieves single object is known as Subjective angle

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Incase of HARC the subjective angle is unity

Incase of UNHARC the subjective angle is not same as objective angle

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There are two slides available one with a vertical slit & the other with a horizontal slit

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The objective angle of deviation is measured with synoptophore

The tubes are set at zero & the slides are inserted

The current is switched on when the patient is ready for test to start

Each eye is stimulated for about 20 second After each eye has been stimulated ,the after

image slides are removed & the automatic binocular flashing device is switched on

Then the patient is asked to draw the after image positions

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A patient with NRC will see the after image as a symmetrical cross

A right esotropic patient with ARC will draw vertical image to the left of horizontal image

A right exotropic patient with ARC will draw vertical image to the right of the horizontal image

A patient may draw only vertical or only horizontal image in the presence of Suppresion

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NRC/HARC RET RXT

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Over correct esodeviation

let patient sit for 30-45 min.

Do the ACT

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repeat the procedure

Esodeviation(positive PAT) Exodeviation

(negative PAT)

Result of ACT

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The principles of treatment were those used to restore the normal sensory relationship of the two retinae

In the majority of strabismus cases, ARC is considered beneficial, and is therefore not treated

The exception is if surgery is to be carried out with a chance of obtaining BSV

However, great care should be taken so as not to produce diplopia

In general the cases considered for treatment will be of mixed correspondence.

Fakhruddin Aliasger

In unilateral strabismus, occlusion is maintained on the fixing eye until the squint had become alternating

It is then changed each day from one eye to the other in order to maintain the visual acuity in each eye, and to discourage the anomalous sensory relationship

The same procedure is adopted if the squint was already alternating

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On synoptophore following exercises are given to stimulate the fovea of the deviated eye

Macular massage

Bi- kinetic retinal stimulation

Flashing

After image test

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These were given using the after-image technique as a control

The giving of the after-image depended on alternative foveal stimulation,

Each fovea was subjected in turn to a stimulus which varied slightly for each eye

With the tube of the major synoptophoreadjusted to the objective angle of strabismus, the stimulus, in a linear form, produced by a specially-constructed slide, was first inserted into the right hand tube so that the beam of light was vertical

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A bright light was turned on behind this slide for approximately 20 seconds and the patient was instructed to observe a red fixation point in the centre of the bar of light so produced

The illumination was then turned on behind a horizontally placed slide in front of the left eye for a further 20 seconds, after which the slides were removed and flashing illumination was commenced in order to stimulate the formation of the after-image

While flashing was in progress the patient was asked to describe the after-image seen projected into space and to indicate the image form by holding two pencils in the appropriate position

Fakhruddin Aliasger

It was usual, at the beginning of the course of treatment, to find the afterimages uncrossed

However, with daily treatment on the major synoptophore, encouraging the patient to bring the lines together, it was found that, in many cases, the two lines would gradually come to form a cross

This appeared only fleetingly at first, but later the cross occurred more permanently

With further treatment, the after-images would form a cross without the aid of flashing illumination

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When the after-images showed, by the formation of a symmetrical cross, that normal retinal correspondence had developed, one of a pair of simultaneous perception slides was inserted; when the picture was centred on the cross, the second slide of the pair was inserted

The two slides were only allowed to remain if the pictures were correctly superimposed, and provided that the cross was still visible

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An operation to restore the eyes to a normal position was not contemplated until the after-image test showed that normal correspondence was fairly constant and that some range of fusion was possible on the synoptophore

Fakhruddin Aliasger