Some whats and whys of the eyes – Part II

Heredity definitely plays a role in nearsightedness (and farsightedness and astigmatism), but it’s not straightforward.  Basically, the more nearsightedness in the family, the greater the odds your children will be.  Sometimes children seem to inherit their eyesight more from the mother, other times more from the father, and sometimes they tend to be a combination of both.  As mentioned in an earlier answer, making sure your child spends plenty of time playing outdoors, may decrease the likelihood (or extent) of nearsightedness.   When it does develop in childhood, it tends to appear and change the most rapidly between the ages of eight and the late teens.

Why are infants’ eyes usually blue?

When a baby is born, the pigment that makes eyes blue, brown, green and everything in between isn’t fully developed.  For most Caucasians, the colored part of the eye, the iris, starts out with very little pigment on the front surface and a different kind on its back.  This prevents light from getting thru the iris itself and allows it only thru the pupil.  Light reflected and scattered from the non-pigmented tissue in the front of the iris gives it a blue color, similar to the way reflected light makes the sky look blue.  As the baby grows, and pigment is produced in this tissue it becomes darker.  Only a little pigment is produced in people whose eyes stay blue.

What does “pink eye” really mean?

Pink eye is a general term for the medical condition, conjunctivitis.  However, both terms are non-specific.  Anything that makes the eye pink is pink eye.  The conjunctiva, a clear, somewhat loose, spongy tissue through which many small blood vessels run, covers the white part of the eye.   Conjunctivitis means swelling of the conjunctiva.  This can be caused by germs (bacteria or viruses), allergies or irritants which trigger blood vessels to expand (making the eye red) and allow the body’s defensive cells into the area.  Different medicines help different kinds of pink eye.  Often, but not always, an eye doctor’s specialized equipment allows her to determine the likely cause, and therefore, the best treatment.