Light projection test

Light projection test

Aim: to test the function of the retinal periphery in patients with opaque media(e.g. cataract patients before cataract operation) because the fundus can not be seen in these patients

Steps:

1)-Be sure that visual acuity is at least (P.L)àif No.PLàno need for this test

2)-The test must be done in dark room.

3)-One eye is tested & the other is covered.

4)-Fall the light on the eye from a distance of(30-50 cm) from 4 directions (upwards, downwards, temporally & nasally) then ask the patient to point to the direction of light.

N.B. you may explain to him at 1^st

Results:

*Accurate projection of light in all directions

*Inaccurate projection of light in all directions

*Inaccurate projection of light in certain direction/s

Oral questions:

*Value of the test

*What the difference between (projection of light) & (perception of light)

*How to test the center of the retina(macular function)

* What are the functions of the macula

Colour sense is tested by colour perception test in eyes with opaque media(by ophthalmoscope or by coloured filters + source of light or by Maddox rod) or Ishihara book in eyes with clear media.

Form sense is tested by visual acuity testing.

Pupillary reaction: tested by papillary light reflex