Cover test.pptx

cover test

1. Cover test Presenter jyoti shah Optometrist

2. COVER TEST IS QUALITATIVE MEASUREMENT OF STRABISMUS. PREREQUISITES OF COVER TEST patient should be co-operative enough to fixate a target. Should have sufficient vision to see target Should have central fixation in both eyes . Latent nystagmus should not be present.

3. Methods of cover test 1.Direct cover test Aim : it conforms the presence of a manifest squint. Procedure Fixate with both eye at a point Normal looking eye is covered and movement of uncovered eye is noticed. if uncovered eye takes the fixation in opposite direction ,manifest squint is present.

4. No movement indicates pseudo strabismus Gross eccentric fixation No vison in the deviated eye

5. Cover uncover test AIM : it establishes the presence and type of heterophoria . Procedure: Performed after direct test conforms absent of manifest deviation one eye covered with occluder and other is made to fixate. In presence of heterophoria the eye under cover deviates(fusion is interrupted) Cover is moved quickly and direction of movement tells the type of heterophoria

6. Alternate cover test it is performed to establish whether the squint is unilateral or alternate and also to differentiate concomitant squint from paralytic squint . Procedure : Pt. is asked to fixate alternately ,placing occluder alternately. It is important to place occluder alternately several times to dissociate the eye and maximize the deviation. Occluder should be transferred quickly from one eye to other to prevent fusion.

7. Observations: In presence of alternate squint either eye fixates and opposite eye under cover deviates and maintains the position of deviation on removing the cover. In presence of unilateral squint , after removal of cover always normal eye takes up the fixation and opposite deviates. In concomitant squint ,primary deviation is equal to secondary deviation and in paralytic squint secondary deviation is greater then primary

8. Limitations A small heterophoria A small angle of esotropia A microtropia A monofixation syndrome A cyclodeviation

9. Thank you