Specialty contact lenses
What you need to know about Contact Lenses
Whether it is for vision correction, eye color enhancement, or treatment of corneal disease, millions of people around the world today enjoy the benefits of contact lens wear.
Approximately 50% of the world’s population requires some form of vision correction. In 1993, it was estimated that 50 million people worldwide choose to wear contact lenses as the primary means of obtaining clear vision.
Contact lenses have evolved from the blown glass lenses of the 1800s which covered the entire front of the eyeball into the high-tech ultra thin plastic corneal lenses of today. They are manufactured to precision specifications and correct a wide range of refractive errors. A variety of lens materials, tints, and wearing options are now available to the contemporary contact lens wearer.
LASIK/ PRK/ ICL
How the Eyes Work & See
The eye can be likened to a camera. As light passes through the cornea and lens it is bent and transposed / focused onto the eye’s film – the retina. The film is then ‘developed’ by the brain, becoming the image that we see and interpret.
As light enters the eye it first passes through the cornea – the clear ‘window’ to the eye. Because the cornea is curved, the light rays bend (refract). Light then passes through the pupil to the lens. The iris – the colored portion of the eye – controls the amount of light that enters the eye with muscles that cause the pupil to contract if there is too much light or to dilate if there is too little light. When light hits the curved surface of the lens it is refracted, or bent even more, so that it focuses properly on the retina. The retina then turns the light into electrical energy, which passes through the optic nerve to the brain stem, and into the occipital lobe where it is converted into an image. To summarize:
• Cornea – clear surface of the eye. Light rays refract as they pass through to the pupil.
• Iris – colored portion of the eye. The iris controls the amount of light that passes through the pupil.
• Pupil – an open space in the center of the iris. Light passes through the pupil to the lens.
• Lens – refracts light to focus it properly on the retina.
• Retina – converts light rays into electrical energy. This electrical energy is passed to the optic nerve.
• Optic Nerve – serves as a pathway to the brain stem, which forwards electrical energy to the occipital lobe.
• Occipital Lobe – electrical energy is converted into an image.
• This process works perfectly in people with 20/20 vision. Imperfect vision occurs when the shape of the eye is irregular or when the eyeball length is above or below average, so that the light rays do not focus directly on the retina – these imperfections are collectively known as refractive errors.
Keratoconus/ Ectasia/ PMD/ Keratoglobus
Keratoconus is a non-inflammatory degenerative disorder of the eye in which structural changes within the cornea cause it to thin and change to a more conical shape than its normal gradual curve / dome shape.
Keratoconus can cause substantial distortion of vision, with multiple images, streaking lights and sensitivity to bright. (light all often reported by the patient). In most cases, corrective Specialty Contact lenses are effective enough to allow the patient to continue to drive.
Corneal collagen cross linking
Corneal Collagen Cross-linking with Riboflavin (CXL) is a newer keratoconus and ectasia treatment that has been proven to strengthen the weakened corneal structure.
CXL is currently in ongoing US Food and Drug Administration (FDA) clinical trials.
Keratoconus is a disease of the cornea which causes the corneal dome to weaken so that it may gradually bulge outward. This bulging is most often in the lower half of the cornea and first presents as progressively increasing astigmatism. However not all astigmatism is due to keratoconus.
In mild or early stages of keratoconus (forme fruste keratoconus), eyeglasses may still adequately correct the astigmatic vision.
Corneal Graft – Keratoplasty
Do you need to wear glasses or contact lenses to help you see objects in the distance clearly? If so, you are nearsighted, or myopic, and this information is provided to help you decide whether or not you want to have your near sightedness corrected or partly corrected with KeraVision™ Intacs.
Presbyopia occurs when the lens of the eye becomes less flexible. Specifically, the lens becomes stiffer and the muscles that control the lens become weaker, hindering its ability to bend and flatten in order to focus light on the retina. As a result, the eye has difficulty focusing on objects up close.
Monovision surgery and surgery that leaves the patient with a low degree of myopia in both eyes are two types of refractive surgery to treat presbyopia.
Floaters and flashes
What are Floaters?
The small specks, ”bugs” shapes or clouds that you sometimes may see moving in your field of vision are called FLOATERS. They are frequently visible when looking at a plain background, such as a blank wall or blue sky.
These visual phenomena have been described for centuries; the ancient Romans called them “muscae volitantes” or “flying flies” since they can appear like small flies moving around in the air. Floaters are actually tiny densities or clumps of gel or cellular debris within the vitreous, the clear jelly-like fluid that fills the inside cavity of the eye behind the Lens.
Laser eye surgeries
Ophthalmic laser surgery was a significant development in ophthalmology over the past three decades. Several types of lasers may be used on different parts of the eye and have been helpful in treating many different types of eye diseases, and conditions.