A nearsighted person sees near objects clearly, while objects in the distance are blurred. As a result, someone with myopia tends to squint when viewing far away objects.
A nearsighted person can easily read the Snellen eye chart (the chart for distance), but finds the Jaeger eye chart (the chart for near reading) difficult to read. This blurred vision results when the visual image is focused in front of the retina rather than directly on it. It occurs when the physical length of the eye is greater than the optical length. For this reason, nearsightedness often develops in the rapidly growing school-aged child or teenager and progresses during the growth years, requiring frequent changes in glasses or contact lenses. It usually stops progressing as growth is completed in the early twenties.
Nearsightedness affects males and females equally, and those with a family history of nearsightedness are more likely to develop it. Most eyes with nearsightedness are entirely healthy, but a small number of people with myopia develop a form of retinal degeneration.
- blurred vision or squinting when trying to see distant objects. (Children often cannot read the blackboard, but can easily read a book.)
- headaches (uncommon)
A general eye examination or standard ophthalmic exam may include:
- visual acuity, both at a distance (Snellen) and close up (Jaeger)
- refraction test, to determine the correct prescription for glasses
- test of color vision, to test for possible color blindness
- tests of the muscles which move the eyes
- slit-lamp exam of the structures at the front of the eyes
- measurement of the pressure of fluid in the eyes
- retinal examination