Tag: eye exam

Why do I Dilate the Eyes?

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I dilate most everybody’s eyes during an eye examination. If you have any health conditions such as diabetes, are taking certain medication, or have  cataracts I will dilate your eyes more often.
Through a dilated pupil I can see more eye structures.  I will use diagnostic lights and lenses that provide a 3 dimensional view of the inside of the eye. If there is a retinal hole, a lesion or fluid, it is much easier to detect through a dilated pupil. If I look through a keyhole, I can see part of the room, if I open the door, I can see everything.
Dilation requires drops in the eye. The effect usually lasts 3-4 hours. Most people notice an increased sensitivity to lights because the pupil is larger. I recommend bringing sunglasses to your appointment. If you think driving may be a problem, arrange for a driver. The drops can also cause a cycloplegic effect, which means focusing on objects up close will be difficult. Try to plan your schedule accordingly. Don’t plan on doing computer work or other close tasks immediately after being dilated.

This is the view of a normal retina looking through a dilated pupil. The optic nerve is the whitish circle on the left, it provides an entrance point to the eye for the blood vessels and an exit pathway for the nerve fibers carrying input to the brain. The 130 million photoreceptors (rods and cones) covering the retina, which appears as an orange background, receive all visual images and send these signals to the brain where the vision process occurs. When you have your eyes dilated at Westside Optometry we will take a similar picture of your eye. Don’t let me forget to show it to you.

Reliability of Vision Screenings

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     The department of motor vehicles, the school nurse and the pediatrician use vision screening to identify vision problems. Screening usually involves standing a given distance from a lettered chart, covering one eye and reading down the chart to the smallest letter possible.
     According to a recent study in Australia, researchers found that results for detecting myopia in 12 -13 year olds was nearly 98%. Good news for the nearsighted, but not so good for the tweens with astigmatism or hyperopia. Only half of the hyperopic children were identified by the vision screening and 25% of the kids with astigmatism were missed.
Screenings are best designed to detect problems with distance vision, and that is important for children socially and physically, but myopia represents the least risk for reading and learning. A myopic child is more likely to notice that the board is blurry and move to the front of the classroom. Hyperopia on the other hand, makes it more difficult to see things close up and astigmatism effects vision at all distances. Children with uncorrected hyperopia and astigmatism will have more difficulty reading and writing and may not even be aware that the difficulty is due to his or her vision. These are the children that may complain of headaches, avoid reading and school related tasks.
     A vision screening test identifies some vision problems, but can miss disorders that have a profound effect on a child’s ability to succeed in school.