Q: I have the dry eye condition and frequently use artificial tears. Is heavy use dangerous?
A: Artificial tears for use over a period of days, weeks, or months must have preservatives to keep them free of bacteria and other microbes. However, if a patient regularly uses artificial tears with preservatives, those chemicals may accumulate and cause eye irritation.
We recommend that patients who apply artificial tears more than four times daily, use preservative-free types, (which come in small plastic tubes), but make sure to use the tube’s contents within 24 hours after opening to avoid bacterial contamination.
Assoc. Prof. Dr. Sudarat Yaisawang
Q: My sister constantly stares at her mobile phone screen. Her doctor says that this might be the cause of her pseudomyopia symptoms. What is this disease and are there treatments that can completely cure it?
A: Pseudomyopia is a temporary condition of nearsightedness caused by slackening of the eye’s near gaze focus muscle. In some children, this muscle does not relax at far gaze, resulting in momentary myopia. This condition occurs when a child use their eyes to focus too much on something; even at far gaze their eyesight still keeps focusing. Thus, the child’s vision resembles nearsightedness. In optometry, this shows nearsightedness, but it is not permanent.
In most cases pseudomyopia occurs in children between the age of six years old through adolescence. It is less common after that age. In adults, pseudomyopia is rare because the gazing mechanism, so common in children, diminishes as people age.
The basic treatment for parents in adjusting their children’s behavior, is reducing near gaze focus activities and increasing outdoor play activities. If you are not sure whether your child is nearsighted, take him or her to an ophthalmologist that specializes in children’s eye diseases. The ophthalmologist will make a proper diagnosis based on whether the eye is able to focus, by using eye drops that temporarily paralyzed the eye-focusing muscle. The ophthalmologist will check the patient’s refractive power for nearsightedness. If pseudomyopia is present, nearsightedness will not be detected after the doctor administers the drug.
Q: I am almost 50 years old, nearsighted, and also have presbyopia. Will LASIK surgery help solve these problems?
A: Presbyopia is the medical name for age-related farsightedness, that usually occurs when people are older than 40 years, which causes loss of clear vision at near gaze or pain around the temples while reading or gazing too long at acomputer screen. This condition does not depend on innate eyesight. Presbyopia is a complex of age-related degeneration of the eye's focusing muscle and the less flexible lens, resulting in blurred near vision. For patients with presbyopia, reading glasses are required for better near vision. Another option is monovision LASIK surgery performed by an ophthalmologist.
Monovision is an optical trick to get around the problem of presbyopia. The doctor sets the laser’s parameters to correct the eyesight of the dominant eye to see clearly at longer distances. For the other eye, the laser leaves some nearsightedness (approximately at 1.5 diopters of myopia), which enables the patient to see in focus at near gaze.
People with monovision see sharp focus in only one eye at a time. Therefore, they might get an eyestrain when doing close work or driving for extended periods. If you are interested in monovision LASIK, you should consult an ophthalmologist to determine if this option is suitable for you.