PowerPoint Presentation

DIPLOPIA CHARTINGDr Pavan Naik

DefinitionIt is when more than one image ( two ) of the object of regard are seen simultaneously

It is Greek work which means double vision. It is caused due to the breakdown in the fusional capacity of the binocular system.

MechanismsMore than one image of the object of regard is formed in the retinae of one or both eyes ( monocular diplopia)

The eyes lose their simultaneous alignment with the object of regard (incomitance of ocular alignment binocular diplopia)

The eyes although aligned, send images to the brain which disallow fusion ( aniseikonia )

Rarely, purely cerebral mechanisms

Is the double vision present even on monocular eye closure?

I. Monocular DiplopiaDiplopia persists on occlusion of one eye.

1. Refractive Astigmatism, Anisometropia2. Corneal - Pterygium, Corneal Scars, Keratoconus3. Lenticular - Dislocated lens, Ectopia lentis4. Iridectomy or Iridotomy5. Dry Eye6. Retinal Maculopathy7. Cortical Diplopia8. Psychogenic

Binocular Diplopia Occurs when both the eyes work together and resolved by occlusion of either eye.

1. Physiological2. Concomitant- decompensating heterophoria(angle of deviation is same in different directions of gaze)3. Inconcomitant (i) Myogenic - thyroid ophthalmopathy (ii) Neuromuscular junction disorders - myasthenia, (iii) Paralytic - Nuclear/Infranuclear - Supranuclear lesions are not normally associated with diplopia (iv) Restrictive -blow out fractures, orbital tumours,Browns syndrome

Is there a mis alignment? If so, in which directions ( or distances ) of gaze? Which are the hypofunctioning ( and hyperfunctioning ) muscles?Do they have a neurogenic pattern, or a restrictive pattern or a neuromuscular pattern or a myogenic pattern?

Abnormal Head Posture

Predominant face turn horizontal rectiPredominant chin elev/dep vertical recti, pattern strabismusPredominant tilt Obliques

Leading questionsIs the diplopia more for distance or near? Is the diplopia predominantly horizontal or vertical?In which direction of gaze are the images maximally separated?To which eye does the outer image belong? Is there a predominant tilt? In which position of gaze does the tilt increase maximally?

Diplopia is maximum ( separation of images) in the field of action of the paralysed muscle.

The false image ( the image belonging to the eye with the hypofunctioning muscle ) is always peripherally situated

Diplopia chart is the record of subjective separation of double images in the nine positions of gaze. Two methods 1. Simple method 2. Electronic devices(hess n lees screens )

The methodComfortable with his head erect and should preferably be still throughout the examination. carried out in a dark room. A red glass is put in front of one of the eyes (red in front of right, R for R, is a convention). It is desirable to use Armstrong goggles since these are shaped to fit the orbital margin examiner holds the torch (vertical source of light) at around m or 1 m (It is important to mention the distance on the chart). This source of light could be horizontal if the complain is of vertical separation of images

The light is held directly in front of the patient at first.

If the patient notes a double image, the relative position of these images is noted. The light is now carried to the right and then to the other 8 positions of gaze. If there is no double vision in primary position, the position in which double vision appears and is maximal is to be noted.

In each gaze position the patient must be asked whether the images are, parallel , distance between two images & tilt if present; colored pencils can be given to patient to show the separation.

Interpretationi. If two images are joined togetherno diplopiaii. If images are separatedconfirms diplopia.iii. Maximum separation is in the quadrant in which (the muscle movesthe eye) the muscle is restricted.iv. The image is displaced towards the field of action of the paralyzed muscle.

v. If horizontal separation with uncrossed imagesesodeviation.vi. If horizontal separation with crossed imagesexodeviation.vii. If vertical separation with uncrossed imagesoblique muscles involved.viii. If vertical separation with crossed imagevertical recti muscle involved

Hess chartBased on the principle of confusionThe principle is foveal projection. Based on the Herings and Sherringtons law of innervation. The dissociation of two eyes is by the means of colors or mirrors (as in Lees screen). Allows for identifying the position of one eye, while the other eye fixes in different positions of gaze.Allows for more objective follow up also.

The test is performed with each eye fixating in turn. It is done at 50 cms. Patient wears complimentary red and green glasses. The red glasses are placed on the right eye first (Red for right, R for R)

The chart has electronically operated board with small red lights. The red lights can be illuminated as needed separately. Patient is asked to place the green light in each of the points on the red light as illuminated on the chart. Next the goggles are changed and the left eye has red goggles and the eye to be tested is right eye.

Example 1Bilateral Superior oblique palsyBoth the charts are to be seen carefully. It is obvious that both the charts show superior oblique underaction. There is a contra lateral inferior rectus overaction. Both the fields are extorted. The midline is shifted in both eyes indicating diplopia in primary position (torsional). Right eye shows slightly greater underaction of superior oblique. Both the charts appear extorted. This was a patient of traumatic bilateral superior oblique palsy.

Example 2Both the eyes show small fields. Overaction is seen in both the eyes on the nasal side. Inner field is closer to outer one so likely to be fresh palsy then an old/ recovered one. Midline is shifted nasally therefore the eyes are also shifted nasally. The patient had a bilateral lateral rectus palsy of recent onset. .

Example 3Right eye field in this example is smaller and the left eye field is larger. The outer upper line is closer to the inner line; the lower one is at a distance. The superior function is lost, that is the inferior oblique and the superior rectus is underacting. The central point is moved downwards so diplopia is there in primary positionThis was a patient of the entrapment of the inferior rectus.

Example 4The field of right eye is smaller compared to the left eye. There is an obvious underaction of inferior oblique. Superior rectus of left eye shows overaction. This was a patient of Right eye inferior oblique palsy. It is important to distinguish this from a Browns syndrome which may be acquired and may show a similar picture.

Treatment1. conservative (glases/prisms)2. surgical(squint correction )

Primary aim is to prevent diplopiaOcclussion of one eye with patch/opaque contact lensIf deviation is less prisms can be givenIn neurological cause we can wait for 6 months to one year

If there is no improvement even after one year in paralytic conditions patient can be advised for surgical correction for deviation to prevent diplopiaPrinciple is--- correction should be in such a way that pt should not have any diplopia in primary and downward gaze of position.

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