The cornea lies right over the iris of the eye and is clear and behaves as a shielding sheet for the eye. A cut or a scratch caused to the cornea is called corneal abrasion. The cornea of the eyes is very sensitive and any minor disturbance caused to it can be very painful. With the onset of corneal abrasion, the eyes become sensitive and painful. If you feel that some foreign body has gained entry into your eye, it is advisable to seek the doctor's help immediately.
By placing a dye on your eye, the doctor will analyze the type of abrasion and the extent of damage caused to the eye. Either eye drops or ointment will be applied to treat the abrasions. Small abrasions heal within two to three days. For people using contact lens, the doctor might advise avoiding them until the abrasion heals for the risk of infection caused by the lens itself. To prevent corneal abrasions, be careful while you are working on machinery that lets loose particles fly. Wear protective glasses while at work with such machines. Cut your nails and your children's nails regularly. Take care while you use your contact lens.
Keratoscope is a medical instrument used to examine the cornea, especially to detect the irregularities in its anterior surface. A keratoscope fitted with a video camera is videokeratoscope which is commonly employed in ophthalmic surgical procedures. Also called Placido's disk, keratoscope uses light to project rings on the cornea. It is a non invasive procedure. One can observe through a keratoscope, reflection of light from the cornea. An inspection of the shape and spacing of the rings which are concentric provides the viewer information about the degree of astigmatism. While in a regular shaped cornea there should be equally spaced symmetric reflections, in patients suffering from astigmatism, the rings will be distorted revealing corneal dystrophy.
In modern methods of sight correction including microsurgical operation of keratotomy and contact lens fitting, it becomes imperative to know the exact shape of the anterior surface of the cornea. For successful use of these methods, keratoscope is employed. Two new types of keratoscopes have evolved. One is the reflective type and the other transparent type. Transparent type of keratoscope is particularly useful in controlling corneal astigmatism during intra ocular surgery.
Such surgical keratometers enable the surgeons to monitor corneal astigmatism during wound closure and adjust suture tension accordingly. From the complex and expensive Terry Keratometer to the simple metal and plastic device of Karickoff, keratometers and scopes are varied, although these devices operate on the basic principle wherein the reflected image of a circular light source show an elliptical shape if significant astigmatism is present. Perhaps the most modern development of the keratoscope concept is corneal topography. Here, the analysis of the reflected image is passed on to a computer. The automated instrument is capable of producing color coded contour maps of the topology of the eye and even a three dimensional visualisation of its surface.
LASIK corrective eye surgery is a type of refractive surgery for correcting myopia, hyperopia and astigmatism. LASIK or Laser Assisted In Situ Keratomileusis uses laser lights to fix your eyesight. Until the invention of contact lenses, eyeglasses alone were used to correct refractive vision errors. Modern techniques like Lasik, Photo refractive keratectomy (PRK) are performed for surgical insertion of artificial lenses to correct eyesight. Blurred vision is the failure of the eye's cornea and lens to refract light rays properly, which affects the images from being focused on the retina. Such blurriness is termed as refractive error. The major causes for refractive error include imperfectly shaped eyeball, cornea or lens.
The procedure involves permanently changing the shape of the cornea for better eyesight. Ophthalmologists use an excimer laser and special knife (microkeatome) to conduct the reshaping. You will be examined completely for any health related issues and the doctor also ensures that your eyes are healthy enough to undergo laser surgery. Few tests are done to measure the curve of the cornea, the size, and position of the pupils, the shape of the eyes and the thickness of the cornea. The tests enable the ophthalmologist to ensure that laser or LASIK eye surgery is an option to you. Ophthalmologists use a microkeratome, a special knife to cut a hinged flap of the corneal tissue. The flap is then folded to reach stroma, the middle section of the cornea, where actual reshaping takes place. An excimer laser is put into the stroma, to vaporize a predetermined portion of the cornea. In other words, pulses from the laser lights reshape the middle portion of the corneal tissue. Once the reshaping is done, the flap that was folded is replaced on the stroma. No stitching is required as both the tissue layers heal through natural process.
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Collection of Pages - Last revised Date: October 19, 2019