Test for angle of manifest squint and Cover-uncover test

Corneal reflection test(Hirschberg test)=Test for angle of manifest squint:

Aim: to test the angle of manifest squint roughly

Steps:

1)-Place a light source in front of of the patient at a distance of 50 cm (just in front of your nose)

2)-The patient is asked to look at this source of light

3)-Observe the position of the corneal light reflection which indicates the angle as follow:

Results:

- In the center of the pupilà0 degree.

-At the papillary marginà10 -15 degrees.

-Midway between the center of the pupil & the limbusà 20 -25 degrees.

-At the limbusà 40 degrees.

-Outside the limbus àeach 1mm =8 degrees + 40 ).

Oral questions:

*How to test for the angle of squint accurately

*What is the types & significance of measurement of angle of squint

*How to test the angle of latent squint

 

Cover-uncover test

Aim: it differentiates between unilateral & alternating concomitant squint.

Steps: The test is done in 3 steps:

1)-The patient is asked to fix a small object(finger or pen) at a distance of 50 cm & the eyes are observed to determine the fixing eye & the squinting eye, then

2)-A cover( piece of paper or your hand )is used to cover the fixing eye àthe originally squinting eye will move to fix the object ( & the originally fixing eye , under the cover ,will squint.

3)-When the cover is removed ,one of 2 possibilities may happen:

*The original state before the test is regained & the other fixing eye returns rapidly to the squinting positionà unilateral squint.

*The other fixing eye (which was previously squinting) continues to fix à alternating squint.

Oral questions:

*What are the types of cover test

*What are the fallacies of cover-uncover test