5. Functional Examination of the eyes
The cones function of the fovea centralis is assessed by:
1-Visual acuity(VA).
2-Colour vision.
The rod function of peripheral retina is usually assessed by:
-Visual Field (peripheral V.F).

6. Quik eye examination should include:
1-V.A.
2-Colour vision.
3.Periphral V.F.
4.Ocular motility.
5.Light papillary reflex.
6.Fund

7. Colour Vision
Colour vision deficiencies occur as a hereditary defect in about 7% of men and 0.5% of women. They are usually transmitted as an X-linked abnormality.
Colour vision abnormalities could be acquired, causes:
1-Retrobulber neuritis.
2-Foveal degeneration caused by vascular diseases.
3-Retinal detachment, involving the fovea.

8. Visual Field
The function of the extrafoveal retina is assessed byV.F Themacula can also be assessed through performing centralV.F.so we have 2 types of V.F.:
1.Central V.F. (macular)=central 30 degree.
2-Periphral V.F.(extramacular)=out of central 30 degree.

9. The peripheral extensions of V.F. is:
50 degrees superiorly
60 degrees nasally.
70 degrees inferiorly.
90 degrees temporally.