Eyes - Refractive Errors.ppt


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Eyes - Refractive Errors.ppt

  2. 2. <ul><li>MÜKAM KARÔTI VACÁLAM </li></ul><ul><li>PANGUM LANGHAYATÄ GIRIM </li></ul><ul><li>YATKRIPÁ TAMAHAM VANDÄ </li></ul><ul><li>PARAMÁNANDA SÁGARAM </li></ul>PRAYER
  3. 3. <ul><li>The ability to see is dependent on the actions of several structures in and around the eyeball. </li></ul><ul><li>When you look at an object, light rays are reflected from the object to the cornea, which is where the miracle begins. </li></ul><ul><li>The light rays are bent, refracted and focused by the cornea, lens, and vitreous. </li></ul><ul><li>The lens' job is to make sure the rays come to a sharp focus on the retina. </li></ul>
  4. 4. <ul><li>The resulting image on the retina </li></ul><ul><li>is upside-down. </li></ul><ul><li>Here at the retina, the light rays are converted to electrical impulses which are then transmitted through the optic nerve, to the brain, where the image is translated and perceived in an upright position! </li></ul><ul><li>Think of the eye as a camera. </li></ul><ul><li>A camera needs a lens and a film to produce an image. </li></ul><ul><li>In the same way, the eyeball needs a lens (cornea, crystalline lens, vitreous) to refract, or focus the light and a film (retina) on which to focus the rays. </li></ul>
  5. 5. <ul><li>If any one or more of these components is not functioning correctly, the result is a poor picture. </li></ul><ul><li>The retina represents the film in our camera. It captures the image and sends it to the brain to be developed. </li></ul><ul><li>The macula is the highly sensitive area of the retina. </li></ul><ul><li>The macula is responsible for our critical focusing vision. </li></ul><ul><li>It is the part of the retina most used. We use our macula to read or to stare intently at an object. </li></ul>
  6. 6. <ul><li>The anterior chamber is the area bounded in front by the cornea and in back by the lens, and filled with aqueous. </li></ul><ul><li>The aqueous is a clear, watery solution in the anterior and posterior chambers. </li></ul><ul><li>The artery is the vessel supplying blood to the eye. </li></ul><ul><li>The canal of Schlemm is the passageway for the aqueous fluid to leave the eye. </li></ul><ul><li>The choroid , which carries blood vessels, is the inner coat between the sclera and the retina. </li></ul>
  7. 7. <ul><li>The ciliary body is an unseen part of the iris, and these together with the ora serrata form the uveal tract. </li></ul><ul><li>The conjunctiva is a clear membrane covering the white of the eye (sclera). </li></ul><ul><li>The cornea is a clear, transparent portion of the outer coat of the eyeball through which light passes to the lens. </li></ul><ul><li>The iris gives our eyes color and it functions like the aperture on a camera, enlarging in dim light and contracting in bright light. The aperture itself is known as the pupil. </li></ul><ul><li>The lens helps to focus light on the retina. </li></ul>
  8. 8. <ul><li>The macula is a small area in the retina that provides our most central, acute vision. </li></ul><ul><li>The optic nerve conducts visual impulses to the brain from the retina. </li></ul><ul><li>The ora serrata and the ciliary body form the uveal tract, an unseen part of the iris. </li></ul><ul><li>The posterior chamber is the area behind the iris, but in front of the lens, that is filled with aqueous. </li></ul><ul><li>The pupil is the opening, or aperture, of the iris. </li></ul><ul><li>The rectus medialis is one of the six muscles of the eye. </li></ul>
  9. 9. <ul><li>The retina is the innermost coat of the back of the eye, formed of light-sensitive nerve endings that carry the visual impulse to the optic nerve. The retina may be compared to the film of a camera. </li></ul><ul><li>The sclera is the white of the eye. </li></ul><ul><li>The vein is the vessel that carries blood away from the eye. </li></ul><ul><li>The vitreous is a transparent, colorless mass of soft, gelatinous material filling the eyeball behind the lens. </li></ul>
  10. 10. EYE DISEASE
  11. 11. <ul><li>Refractive errors </li></ul><ul><li>Conjunctivitis </li></ul><ul><li>Cataract </li></ul><ul><li>Glaucoma </li></ul><ul><li>Corneal Ulcer </li></ul><ul><li>Injuries of the eye </li></ul><ul><li>Diabetic Retionopathy </li></ul>COMMON DISORDERS OF THE EYES
  12. 12. <ul><li>Name of the disease & terminologies </li></ul><ul><li>Etiology </li></ul><ul><li>History, signs and symptoms </li></ul><ul><li>Physical examination </li></ul><ul><li>Investigation </li></ul><ul><li>Treatment according to allopathic medicine </li></ul><ul><li>Other therapies </li></ul><ul><li>Yoga practices </li></ul><ul><li>Books and journals for reference </li></ul>
  13. 13. REFRACTIVE ERRORS imperfections in the focusing power of the eye, for example, hyperopia, myopia, and astigmatism. Hyperopia (Long sightedness) Myopia (Short sightedness) Astigmatism
  14. 14. <ul><li>Refractive errors are disorders, not diseases. </li></ul><ul><li>A refractive error means that the shape of the eye does not bend light correctly, resulting in a blurred image. </li></ul><ul><li>Light has to be refracted or bent by the cornea and the lens to the retina in order for us to see. </li></ul><ul><li>Normally, the rays of light entering the eye are brought to a precise focus on the retina, the light sensitive layer lining the back of the eye. </li></ul><ul><li>When such a focus is not achieved, a refractive error results and the vision is not clear. </li></ul>DEFINITION FOR REFRACTIVE ERROR
  15. 15. <ul><li>When the light rays are focused in front of the retina, the resulting condition is termed Myopia (short-sightedness). </li></ul><ul><li>In Hyperopia (long-sightedness), the light rays come to a focus behind the retina. </li></ul><ul><li>Astigmatism (cylindrical error) occurs when incoming light rays are unable to reach a common focus within the eye. </li></ul><ul><li>Wavefront a measure of the total refractive errors of the eye, including nearsightedness, farsightedness, astigmatism, and other refractive errors that cannot be corrected with glasses or contacts. </li></ul>
  16. 16. <ul><li>Myopia (distant objects are blurry) </li></ul><ul><li>Hyperopia (close objects are blurry) </li></ul><ul><li>Presbyopia (aging of the lens in the eye) </li></ul><ul><li>Astigmatism (blurred vision at all distances) </li></ul>Common refractive disorders are
  17. 17. <ul><li>Long sighted patients have a blurred vision of close objects. </li></ul><ul><li>They suffer from eye strain and headache after doing close work. </li></ul><ul><li>Irritability and nervousness after prolonged concentration. </li></ul>SYMPTOMS OF HYPEROPIA
  18. 18. <ul><li>Children complain of their inability to see the blackboard. </li></ul><ul><li>Shortsighted people often have headaches or suffer from eyestrain. </li></ul><ul><li>They have blurry distant vision and tend to squint for a better image. </li></ul>SYMPTOMS OF MYOPIA
  19. 19. <ul><li>Patients with astigmatism have blurred or distorted vision at all distances. </li></ul><ul><li>It can also cause images to appear doubled, particularly at night. </li></ul><ul><li>Patients have inconsistent difficulty focusing on various objects such as finely printed words and lines. </li></ul><ul><li>Headache and fatigue are common as the person tends to strain their eyes. </li></ul><ul><li>Squinting, eye discomfort and </li></ul><ul><li>irritation are also frequent. </li></ul>SYMPTOMS OF ASTIGMATISM
  20. 20. <ul><li>Tiny blind spots appear at the edges of the visual field (peripheral or side vision) that slowly get larger and spread </li></ul><ul><li>Blurred vision </li></ul><ul><li>Appearance of colored halos around lights </li></ul><ul><li>Adjustment problems on entering a dark room </li></ul><ul><li>Repeated difficulties that new eyeglass prescriptions do not help </li></ul><ul><li>Peripheral (side) vision is decreasing </li></ul><ul><li>Severe eye and head pain </li></ul><ul><li>Nausea or vomiting </li></ul><ul><li>Appearance of rainbow-colored halos around bright lights </li></ul><ul><li>Rapid loss of vision </li></ul>SYMPTOMS OF GLAUCOMA
  21. 21. <ul><li>Refractive disorders are commonly treated using corrective lenses, such as eyeglasses or contact lenses. </li></ul><ul><li>Refractive surgery can also be used to correct some refractive disorders. </li></ul>TREATMENT
  22. 22. <ul><li>Non surgical options for the correction of refractive errors include spectacles and contact lenses. </li></ul><ul><li>Spectacles contain lenses that suitably refract the incoming rays of light and enable them to focus on the retina. </li></ul><ul><li>Contact lenses perform the same function but are placed on the cornea-the clear front portion of the eye. </li></ul><ul><li>Hence, they provide better cosmesis and improved quality of vision in the higher refractory errors. </li></ul>How are refractive errors corrected?
  23. 23. <ul><li>Surgical procedures attempt to eliminate the external aids like glasses and contact lenses. </li></ul><ul><li>In Radial Keratotomy, where four to eight corneal incisions are made involving 95-99% of the corneal thickness, to flatten the central corneal. </li></ul><ul><li>The weakened peripheral cornea is pushed outwards by the pressure within the eye. </li></ul><ul><li>This results in a flattening of the central cornea which corrects a myopic refractive error. </li></ul><ul><li>Similar incisions when made in a hexagonal fashion in the mid-peripheral cornea result in a forward protrusion of the central cornea. </li></ul>
  24. 24. <ul><li>This procedure is termed Hexagonal Keratotomy and is used to treat hyperopia. </li></ul><ul><li>To correct astigmatism, straight or curved incisions are made in the mid peripheral cornea and the procedure is termed Astigmatic Keratotomy. </li></ul><ul><li>All incisional procedures weaken the structural integrity of the cornea. </li></ul><ul><li>This theoretically results in an increased tendency of the cornea to rupture following trauma. </li></ul>
  25. 25. <ul><li>The use of the Excimer Laser in corneal refractive surgery has greatly increased the safety of the procedure as the refractive correction is achieved by the removal of as little as 10%-20% of the total corneal thickness. </li></ul><ul><li>Excimer Photorefractive Keratectomy (PRK) is now a procedure used all over the world and has helped thousands of patients say goodbye to glasses. </li></ul><ul><li>A recent advance in the treatment of high refractive errors is a procedure termed Laser In-situ Keratomileusis (LASIK) which is often an adjunct to PRK. </li></ul>
  26. 26. <ul><li>These procedures are done as out-patient procedures and patients using topical anaesthetic drops and the patients can go home right after the procedure. </li></ul><ul><li>Thus, surgical procedures like PRK and LASIK are leading us towards a world without glasses. </li></ul>
  27. 27. YOGA PRACTICES <ul><li>YOGA IS BALANCE (SAMATVAM) </li></ul><ul><li>I A Y T CORRECTS IMBALANCES </li></ul><ul><li>AIMS : </li></ul><ul><li>STRESS REDUCTION </li></ul><ul><li>RELIEF OF PAIN </li></ul><ul><li>MEDICATION REDUCTION </li></ul>
  28. 28. <ul><li>Eye defects, which do not require surgery, like eye strains, watering of the eyes, itching in the eye region, eye pain, diminishing visionary power, redness, blurring vision, near and far sightedness can be cured through yogic treatment. </li></ul><ul><li>On the other hand organic defects like Cataract, Glaucoma etc requiring surgery need eye specialists. </li></ul><ul><li>Patients having any eye disorder can cure the problem by having a proper diet, doing yogasanas followed by some eye exercises. </li></ul>SPECIFIC PRACTICE
  29. 29. <ul><li>Eye exercises : </li></ul><ul><li>Be seated in Sukhasan (Easy pose). </li></ul><ul><li>Without moving the head, look upwards for 2 seconds and then downwards. </li></ul><ul><li>Then look towards right for 2 seconds and then look to the left. Close eyes for 6-8 seconds. </li></ul><ul><li>Then move eyes in clockwise direction. Repeat this twice and rest for 6-8 seconds. Repeat in anti-clockwise direction. Rest. </li></ul><ul><li>Rub the palms against one another for 6-8 seconds, and place them on eyes for 6-8 seconds, without exerting any pressure. Rest. Repeat palming 2-3 times. </li></ul>
  30. 30. <ul><li>For healthy eyes and improved sight : </li></ul><ul><li>Practice Jal Neti Kriya. </li></ul><ul><li>Do not work in hot sun, as bright light destroys Vitamin A. </li></ul><ul><li>Practice Pran mudra </li></ul><ul><li>In the mornings after cleaning mouth, fill it with water so that the cheeks get puffed up and then splash water on the eyes several times. Then throw out water from the mouth. Keep eyes closed for some time. This will make eyes feel cool and fresh. </li></ul><ul><li>The distance while watching T.V. should be at least 3 meters (10 feet) and while reading or writing, the book should be at a distance of 30 cm (12 inches). </li></ul>
  31. 31. <ul><li>General considerations : Some eye problems such as nearsightedness or farsightedness do not limit the trainee in the selection of practices. On the other hand acute eye problems and glaucoma should be taken into account. </li></ul><ul><li>Contraindications : Inverted asanas (including Padahastasana) are strictly contraindicated in glaucoma. No inverted asanas are recommended, if the eye vessels are weak, and in conjunctivitis. </li></ul>
  32. 32. <ul><li>Recommendations : Trataka also helps according to Yoga tradition. Glaucoma is a stress related disease, patients with this problem may benefit from relaxation and calming pranayama, and they should be properly medically treated. </li></ul>
  33. 33. <ul><li>Recommended Asanas : </li></ul><ul><li>Suryanamaskara (Sun salutation) - invigorates all the organs of upper part of the body, the facial tissues and the central nervous system. </li></ul><ul><li>Trikonasana (Triangular pose) - develops visionary power of the eyes. </li></ul><ul><li>Yogamudraa (Yogi pose) - provides benefits like removing gastric troubles and constipation, correcting disorders of spine, and enhancing sexual potency. </li></ul><ul><li>Savasana (Corpse pose) - Relaxes the body. </li></ul>