Lentes de Contacto
İzmir Kaskaloglu Eye Hospital
Following a routine eye examination at Kaskaloglu Eye Hospital, your doctor will evaluate the cornea with an Orbscan which scans the cornea for detailed topography. In this way we can prescribe contact lenses that are best suited for your needs.
We keep the most standard contact lenses in stock at all times; cosmetic or fun lenses take a few days to come in. We can also provide free samples of brand name disposable lenses.
The following brands are available:
- Wessley Jessen
CibaVision Progressive disposable contact lenses provide an excellent solution for the young reading glass user. Ask your doctor for a free pair.
You can order contact lenses by e-mail firstname.lastname@example.org . Just send us your contact lens prescription or the numbers on the box or the bottle for a quote.
Some people develop glaucoma even without evidence of increased pressure inside the eye. In fact, recent studies show that up to 50% of people with glaucoma may not have high eye pressure measurements. For example, people of Japanese descent are more prone to have glaucoma without elevated eye pressure.
Many studies are in progress to discover the reason for glaucoma damage in people who do not have increased eye pressure. The two leading theories are that damage to the nerve is caused by poor circulation to the nerve or that abnormally high concentrations of naturally occurring chemicals or hormones cause the damage.
Scientists who believe that poor circulation causes glaucoma have used special ultrasound testing to show decreased blood flow to the eyes of some people with glaucoma. Many of these people with “normal pressure” glaucoma also have other problems with their circulation, such as heart disease, poor circulation to their legs and feet, or hardening of the arteries.
Other scientists have shown increased concentrations of glutamate and other chemicals in the eyes of people with glaucoma. These chemicals are naturally produced by the body, and in normal amounts, help with normal eye functions. In abnormally high concentration, however, these naturally-occurring chemicals can actually harm the very nerve tissues from which they are produced. Scientists still have not discovered why the body produces abnormally high amounts of these chemicals in eyes with glaucoma.
Doctors and scientists are working to discover treatments to poor circulation to the optic nerve and treatments to decrease the concentration of these harmful hormones in the eye. Studies are under way to determine if improving circulation or decreasing the hormone concentration will help stop damage from glaucoma.
Contact lenses are thin, curved plastic disks designed to cover the cornea, the clear front covering of the eye. Contacts cling to the film of tears over the cornea because of surface tension, the same force that causes a drop of water to cling to the side of a glass.
Contact lenses are used to correct the same conditions that eyeglasses correct:
Astigmatism (distorted vision)
Presbyopia (trouble reading with age)
Special tinted contacts can be used to change the color of the eyes to various degrees. Contact lenses are sometimes used therapeutically in eye diseases where an uneven cornea blurs vision, such as keratoconus or scarring. They are also sometimes used for corneal abrasions to assist in healing.
These photographs, called disc photos, are particularly helpful if your doctor believes that you are a “glaucoma suspect”. A glaucoma suspect is a person whose optic nerve appearance is suspicious for glaucoma, but does not demonstrate definite glaucoma damage. If you are a glaucoma suspect, your doctor will want to examine your optic nerve two or three times a year, and compare to the baseline disc photos to detect definite glaucoma damage as soon as it occurs. This will allow your doctor to begin treatment before the glaucoma has a significant effect on your vision.
Another way to measure the amount of damage to the nerve is to measure the amount of peripheral or side vision that has been lost. Glaucoma does not affect your central reading vision until the late stages of the disease. At this late stage, vision may already be deteriorated to the point of partial blindness. Therefore, it is important to measure the peripheral vision in the early stages of the disease, so that proper treatment can be given to prevent blindness. This is accomplished with visual field testing, which is an examination that measures the amount of vision lost.
To test the visual field, your doctor uses an instrument that flashes lights of various intensities. You place your head against a head rest and stare at a target light directly in front of the eye being tested. The machine then flashes lights in your peripheral vision. Some of these lights are bright and easy to see. Others are so dim that they are impossible to see even if you have no visual damage. Most lights are somewhere in between. When you see the light, you press a button and the machine registers your response. The machine then prints out a map showing any areas that you cannot see properly. Your eye doctor can repeat this measurement periodically to determine if the glaucoma treatment has been effective in stabilizing the damage.
There are other types of specialized testing that have recently become available, such as measurement of the thickness of the nerve with a technique called scanning laser polarimetry (GD Nerve Fiber Analyzer), and short wavelength perimetry, which uses colored lights to test the visual field (peripheral vision). Both of these technologies are particularly helpful if a person is suspected of having glaucoma, but there is no definite damage visible (glaucoma suspect).
Rigid contacts were the first lenses; they were developed in the 1960’s. They are made of a type of plastic called PMMA, which is very durable, but does not allow oxygen in the air to directly reach the cornea. When the eye blinks, the lens moves, which allows the oxygen dissolved in the tears to reach the cornea. While rigid lenses are probably the least comfortable type of contacts to wear, some users prefer them for their durability and lower cost.
Newer rigid lenses made of plastic combined with other materials, such as silicone and fluoropolymers, allow oxygen in the air to pass directly through the lens. They are called gas permeable. Gas-permeable lenses are less durable than conventional rigid lenses but are more comfortable. Some gas-permeable lenses are extended wear and may be worn overnight for up to seven days.
Soft contact lenses
These lenses are made of plastic materials that incorporate water. The water makes them soft and flexible, as well as allowing oxygen to reach the cornea. Most of the contact lens wearers use soft contact lenses. Some soft contact lenses are extended-wear lenses, which means they are designed to be left in the eye overnight. It is recommended that extended-wear lenses be removed weekly, at a minimum, for thorough cleaning and disinfection. Some contact lenses are approved for wear up to 30 days. Soft daily wear lenses should never be used as extended-wear lenses. Extended-wear lenses can be used as daily-wear lenses. Studies have shown increased risk of corneal infections associated with extended wear contact lens use.
Disposable soft contact lenses
Disposable lenses for daily or extended wear have recently become available. The lenses are discarded and replaced each week. These lenses are convenient and may reduce the chance of allergic reaction and deposit formation.
Bifocal contact lenses
These lenses correct both reading and distance vision. They can eliminate the need for reading glasses.
Rigid lenses that are not gas permeable are more likely to scratch the cornea if the lens does not fit properly or if the lens is worn while sleeping. They are also more likely to slide off the cornea and become hidden under the lid.
Rigid lenses traditionally had a reputation for “popping out” of the eye. New lens designs have minimized the chance of losing a contact, even during vigorous exercise. Rigid gas-permeable lenses may allow more protein build-up than rigid non-gas-permeable lenses. Protein build-up results in discomfort, blurring and intolerance to the lenses. You will need special cleaning solutions to dissolve the protein.
Daily-wear lenses should never be worn as extended-wear lenses. Misuse can lead to temporary and even permanent damage to the cornea. People who wear any type of lens overnight have a greater chance of developing infections of the cornea. These infections are often due to poor cleaning and lens care.
Contact lenses must be properly cleaned and disinfected when you remove them to kill germs and prevent infection. At the time you insert your contact lenses, you should thoroughly rinse the case with warm water and allow it to dry. All contact lens cases need frequent cleaning, including disposable lens cases.
Soft extended-wear contacts are the most likely to have protein build-up and cause lens-related allergies. Soft daily-wear lenses are less likely to create problems. Rigid gas-permeable or disposable lenses may be good choices for someone with allergies.
Homemade saline solutions have been linked to serious eye infections and should never be used.
Any eye drops, even nonprescription ones, can interact with all types of contact lenses. Check with you ophthalmologist before you use any eye drops.
Most people who need vision correction can wear contact lenses, but there are some exceptions. Some of the conditions that might keep you from wearing contact lenses are frequent eye infections, severe allergies, dry eyes, a work environment that is very dusty or dirty or the inability to handle and care for the lenses properly.
Want to learn more about getting contact lenses? Contact Kaskaloglu Eye Hospital today.
Son Güncelleme 12 Agosto 2020 Saat 08:33 am