In ALK, a thin layer of tissue is removed from the front surface of the cornea. Then, to reshape the cornea, the doctor removes tissue from the middle layer of the cornea using an instrument called a microkeratome, which functions similarly to a carpenter’s plane. Finally, the top layer of tissue is replaced. ALK is usually reserved for patients with severe nearsightedness or low degrees of farsightedness.
Corneal Topography is a test that measures the curvature of the front of your eye at many different points. This information is used to aid in the diagnosis of conditions such as keratoconus or high astigmatism, and to help the doctor in fitting contact lenses to improve the patient’s vision.
Dilation of the pupil refers to the technique of instilling eye drops which temporarily make your pupils larger. This gives your doctor an opportunity to see more of your retina when he or she looks into your eye to examine its health. It’s a lot like looking into a keyhole to see what’s inside a room; the bigger the keyhole, the more you can see.
A commonly noticed effect of the drops is the temporary reduction in the ability to focus on things that are near to you. Your vision will start to return to normal anywhere from between four to six hours. During this time, you may receive some special temporary sunglasses to wear to protect you from bright light.
After your exam, the doctor may write an eyeglass prescription for you. If you choose to fill it at University Eyewear, you will be assisted in your frame and lens selection by a New York State licensed ophthalmic dispenser (optician). If your eyes are still dilated, it may be a little more difficult to see yourself in the mirror while trying on new frames.
Fluorescein angiography is a diagnostic test which is a specific part of a photographic study. A vegetable-based fluorescein dye is injected into a vein in one of your hands or arm and sequential black and white photographs are taken as the dye progresses through the retinal veins.
Before the test
The doctor will explain what the procedure is and will ask you if you understand or have any questions. A nurse will also speak with you and answer any questions that you may have. The nurse will also take your blood pressure and pulse. It is important to tell the nurse and the doctor if you have any allergies to any medications or foods before you have the fluorescein angiography.
During the test
The nurse will be in the room with you while the doctor is performing the test. Some patients feel nausea during the procedure, but it usually lasts for just a few seconds. If any of the dye escapes from a small vein when it is injected, it is possible for your skin to feel very warm and yellow blotches may appear. Allergic reactions to the fluorescein dye are very uncommon. If an allergy occurs, you will begin to develop a rash or feel an eruption of itchiness. The reaction is usually treated with an oral dose of an antihistamine. The test lasts for only five to ten minutes.
After the test
The doctor will ask you to stay in the clinic for about an hour before you will be allowed to go home. During that time, the nurse will take your blood pressure and pulse again and will give you additional instructions. You will be given an appointment to come back to the clinic for follow-up care. If you have any pain, eye discharge or other problems or questions, call our service when you get home. The day after the procedure is done, the nurse will call you to ask if you have any concerns or problems. He or she will give you additional instructions when needed.
The LASIK procedure uses both surgery and a laser to treat nearsightedness, farsightedness and astigmatism. In LASIK, the doctor surgically creates a flap of tissue on the front surface of the cornea. The flap is folded back and a laser is used to reshape the layer of tissue underneath (the middle layer of the cornea). Once this is completed, the flap is repositioned and allowed to heal. Candidates for LASIK should be at least 18 years old, have stable vision and no abnormalities of the cornea or external eye.
In LTK, the doctor uses a laser to heat a series of small, dot-shaped areas of the cornea. This causes the corneal tissue to expand and the curvature of the cornea steepens. LTK is used to treat people who are farsighted. Candidates for LTK should be at least 18 years old, have stable vision and no abnormalities of the cornea or external eye.
The cornea is the clear covering of the front of the eye which bends (or refracts) light rays as they enter the eye. For clear vision to occur, the cornea must have the correct shape and power to focus incoming light rays precisely on the retina at the back of the eye. If the cornea is too steep, too flat or irregular in shape, it cannot bend light at the angle needed to focus on the retina. As a result, eyeglasses or contact lenses may be needed to refract the incoming light rays at the angle needed for clear vision. In a nearsighted eye, for example, the cornea’s shape causes incoming light rays to focus in front of the retina.
All corneal modification procedures are intended to alter the curvature of the cornea so that incoming light is refracted at an angle that allows it to focus precisely on the retina. This may eliminate the need for eyeglasses or contact lenses, or reduce the power of prescription lenses needed.
Those interested in any of the corneal modifications should first have a comprehensive eye examination to evaluate their eye health and determine their vision needs.
Monovision is a treatment in which one eye is fit with a lens for seeing things at a distance and the other eye is fit for seeing close up. After a period of adjustment, the brain switches to the eye which is giving the clearest image at the time. Typically, monovision has a higher success rate than bifocal lenses.
While monovision is successfully used by many people, others find adapting difficult. Mildly blurred vision, dizziness, headaches and a feeling of slight imbalance may last for a few minutes or for several weeks as you adapt. Generally, the longer theses symptoms last, the more unlikely it is that you will adapt successfully.
Eyecare practitioners urge patients new to monovision to avoid visually demanding situations at first, and instead, to wear their new lenses only in familiar situations. For example, it may be better to be a passenger rather than a driver in a car. In fact, you should only drive with monovison correction if you can pass your driver’s license eye examination while wearing those lenses.
Ortho-K is a non-surgical procedure that involves the wearing of a series of specially designed rigid contact lenses to progressively reshape the curvature of the cornea over time. It is used to treat low to moderate nearsightedness and low degrees of astigmatism. As the curvature of the eye changes, the patient’s myopia is reduced and the natural vision improves. At the end of the therapy, retainer contact lenses are worn to maintain the improved vision. The amount of time that these retainer lenses are worn differs with each patient, but usually varies from several hours of wear per day to several hours of wear two or three days per week. All ages benefit from Ortho-K. It is especially effective in dealing with progressive myopia in children.
Myopia: Mild to moderate degrees of myopia (20/200 or better unaided visual acuity) may be corrected to 20/20 or 20/30. Higher degrees of myopia may achieve dramatic improvements allowing the patient to have functional vision without lenses, which would have been previously impossible.
Astigmatism: Most mild astigmatic conditions can be reduced dramatically or eliminated. Higher amounts of astigmatism may be partially improved. With computerized corneal topography and new contact lens designs results have improved dramatically. Many patients utilizing these lenses in conjunction with newer techniques are able to see results in much shorter periods of time.
Ocular photography is when pictures are taken of the eye for visually recording an abnormality in order to best monitor a possible change in its appearance. The Contact Lens Specialty Service limits its photography to the eyelids, cornea, sclera and iris.
Ocular prosthetics are for those patients who have had an eye removed because of disease or trauma. At the time the eye is removed, an implant is put in by the surgeon. Once the eye heals, an artificial eye is made to give the patient a normal appearance. For those patients whose eye was not removed, a cover shell can be made. This gives the eye a normal appearance and matches the other eye.
In photorefractive keratectomy, the doctor uses an excimer laser to remove a thin layer of tissue from the center of the cornea. The laser produces a uniform, concentrated beam of high energy ultraviolet light that is precisely focused onto the cornea. During the procedure, the laser’s light energy is converted into chemical energy which evaporates molecules of corneal tissue in very precise amounts. By altering the curvature of the cornea in this way, PRK helps reduce or eliminate moderate nearsightedness and astigmatism. Candidates for PRK should be at least 18 years old, have stable vision and no abnormalities of the cornea or external eye.
In RK, the doctor surgically flattens the cornea by making a series of small, radial (like the spokes of a wheel) incisions in the periphery of the cornea. This flattens the cornea and changes its focusing power so that light rays fall precisely on the retina. Radial keratotomy is used to treat nearsightedness and some forms of astigmatism. Candidates for RK should be at least 18 years old, have stable vision and no abnormalities of the cornea or external eye.
The ability to learn in school, achieve on the job and enjoy sports and recreation depends upon efficient vision. Vision therapy can help individuals achieve and maintain good vision throughout life. Optometric vision therapy, also referred to as visual training or orthoptics, is a treatment regimen to correct or improve specific dysfunctions of the visual system that have been diagnosed from a comprehensive analysis. Vision therapy can treat strabismus, amblyopia, accommodation, ocular motor functions, visual-perceptual-motor abilities and many other developmental, acquired or congenital visual dysfunctions. Treatment plans can encompass the use of lenses, prisms and patching among others. Because the therapy is individualized, the procedures used and the duration of therapy are dependent upon the nature and severity of the problem being treated and the specific needs of the patient. Vision therapy is effective for patients of any age.
A visual perceptual evaluation is a comprehensive process to evaluate a person’s ability to interpret and organize visual information. Visual processing skills such as form recognition, copying, visual memory and directional concepts are carefully evaluated. Patients with poor perceptual abilities may resist school work and be misinterpreted by the parents and teachers as being lazy; they may give up on a task before they have even tried; they may be unable to complete assignments in a reasonable amount of time; they may easily confuse letters and words.