Category: Myopia

Wearing Contact Lenses Overnight

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Have you ever wondered what would happen if you wore your contact lenses overnight? Unexpectedly stayed the night at a friends house and didn’t have anywhere to put your lenses? Enjoying a  late night and fall asleep with your contacts on?

It happens, contact lenses get worn too long and sometimes over night. Some contact lenses are better for this than others. I prescribe and fit people with the intention of overnight use. I also warn patients about the risks they are taking with their eyes.

Depending on the contact lens type and material, oxygen is reduced to the cornea. Movement of the contact with each blink aids the transmission of oxygen. When you are sleeping with the contact lens, the eye is closed and no oxygen gets to the cornea. There is no blinking either so the lens doesn’t move. The reduction in oxygen causes the cornea to swell, if the lens allows plenty of oxygen to get to the cornea during the day, the cornea will deswell and return to normal. However, if the cornea remains swollen, and you sleep in the lens consecutive nights, blood vessels will begin to grow into the cornea. Sometimes the eye responds by becoming inflamed, red and painful.

Another risk of leaving the lenses in overnight is infection. Typically when a lens is removed it is thrown away or placed in disinfecting solution. In the morning a new lens or a clean, disinfected lens is applied to the cornea. Microbials build up on a lens that is worn continually. If your cornea is compromised by a scratch or edema, the bacteria will infect the eye.

If you have been prescribed extended wear contact lenses, stay compliant to your wear schedule, once in awhile overnight or 6 consecutive nights. Clean and replace your lenses as prescribed. If you are wearing your daily wear contacts overnight, let’s talk about a safer option. This may include a higher oxygen material or even LASIK. Sometimes the prescription can be a limiting factor. If the prescription is higher,  farsighted or is toric and corrects astigmatism, the lenses will be thicker and reduce oxygen transmissability.

What are the Advantages of Daily Use Contact Lenses?

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Soft daily use contact lenses have been available since 1995. The obvious advantage of replacing contact lenses daily is placing a clean, sterile, well-hydrated lens in your eye each morning. Even with the best cleaning and hygiene; lenses get dirty, lose their ability to stay wet and protein adheres to the surface. These factors reduce comfort, cause dryness and decrease lens clarity.

The other advantage is the elimination of contact lens solutions and the complications resulting from solutions. The contact lens solution industry changes as often as the lenses. Most contact lens complications result from sensitivity to the solution or poor compliance. Eliminating this component from the care of contact lenses, resolves multiple problems.

Probably the greatest advantages to patients is the convenience. No more contact lens solutions, no contact lens cases, just a clean, clear and comfortable lens each day.

For intermittent wearers, someone who uses lenses for sports, social events or infrequently, the daily lenses are easier to keep on hand, in a gym bag, briefcase or backpack. No more trying to remember how old a lens is, or opening the case to find dried up lenses.

One of the disadvantages is that not all prescriptions are available in daily disposable lenses. There are some toric lenses (astigmatism correction) in limited powers but not enough. Currently there is not a decent multifocal daily contact lens (although, this will be available in the future). The second disadvantage of daily replacement lenses is they are not designed for overnight use and must be removed before sleeping.

Is LASIK Right for Me?

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I discuss LASIK with several patients each week and realize I have never written about it. LASIK is a refractive procedure that quickly, painlessly and permanently changes the corneal topography (shape of the front of the eye) to correct a person’s vision. Many people are candidates for the procedure, but some are “better” candidates than others. My strongest recommendation goes to people with astigmatism. This refractive condition is usually caused by the shape of the cornea and often makes contact lens use challenging or impossible. My second favorite candidate for LASIK are people with myopia or  nearsightedness. I do want to qualify this because some myopes are not great candidates. Someone who reads and works at the computer comfortably without glasses or contact lenses will require more education about future vision changes and glasses. The other end of the myopic spectrum are people who are really really nearsighted and too much corneal tissue would have to be removed to be safe. Otherwise most nearsighted people are very good candidates and enjoy the results.

Other important criteria include stable vision. LASIK will not prevent  the prescription from changing. I like to see no changes in the distance vision for at least 12 months, preferably 2 years. If the vision is going to change, it will, with or without the refractive procedure. If you have the procedure, you can expect good vision without glasses for a very longtime.

The actual laser procedure takes 2 minutes or less per eye. Many precise measurements are taken before the procedure. Proper alignment with the laser is made in all axes. A super thin flap of cornea is created with the Intralase Method which uses tiny, ultra-precise pulses of light. It is laid back while the surgeon lasers the tissue underneath it to correct the refractive error. The flap is carefully replaced and smoothed into place. And that is the extent of the actual LASIK. The rest is healing and post-operative care. Some lifestyle modifications are required initially, but most people are surprised how much they can do and see right after surgery.

If you have any questions or comments about refractive surgery, please leave a comment or call the office (707)762-8643.

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.