1.   Also, in winter in northern latitudes, the oblique angle of the sun means fewer effective rays reach the skin.

2.   During the northern winter, direct solar rays focus on the Southern Hemisphere while oblique rays reach northern latitudes.

3.   Farsightedness, or hyperopia, occurs when the eyeball is too flat, so light rays reach the retina before they come into focus.

4.   In the northern winter, the direct rays of the sun are focused on the southern hemisphere while the oblique, weaker rays reach northern latitudes.

5.   Under the microscope an eye melanoma is indistinguishable from a cutaneous melanoma, yet these ocular tumors arise in areas that ultraviolet rays cannot reach.