Hard Contact Lenses

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This presentation emphazises on the details of Hard Contact Lenses

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  • Certainly Contact lenses have evolved a lot from so many years. Hard Contact Lenses made of PMMA gas permeable contact lenses or rather Soft Contact Lenses are a preferred choice these days. Thanks for the information. :)

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  • Certainly Contact lenses have evolved a lot from so many years. Hard Contact Lenses made of PMMA gas permeable contact lenses or rather Soft Contact Lenses are a preferred choice these days. Thanks for the information. :)
       Reply 
    Are you sure you want to  Yes  No
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Hard Contact Lenses

  1. 1. Dr. Ankit Punjabi P.G., Dept of Ophthalmology K.I.M.S. Hospital, Bangalore Email: drankitalways@gmail.com
  2. 2. HARD CONTACT LENS <ul><li>PMMA or its congeners </li></ul><ul><li>Advantage : </li></ul><ul><li>Less cost </li></ul><ul><li>Easy to handle </li></ul><ul><li>Easy to clean, store & maintain </li></ul>
  3. 3. HARD CONTACT LENS <ul><li>Durable and long life span (15/20 yr.) </li></ul><ul><li>Easy to fit, only one sitting (visit) necessary </li></ul><ul><li>Better vision due to better optics of anterior refracting surface </li></ul><ul><li>Do not absorbs significant amount of late </li></ul>
  4. 4. HARD CONTACT LENS <ul><li>Disadvantages : </li></ul><ul><li>Longer period of adaptation </li></ul><ul><li>Wind and dust bother the wearer </li></ul><ul><li>May fall off spontaneously on lateral version </li></ul><ul><li>May break under enough pressure </li></ul><ul><li>May warp and go flat when exposed to excess heat </li></ul><ul><li>Difficult to wear intermittently as they require period of adaptation </li></ul>
  5. 5. INDICATION <ul><li>Astigmatism </li></ul><ul><li>Aphakia </li></ul><ul><li>Progressive myopia </li></ul><ul><li>Keratoconus </li></ul><ul><li>Topical medications </li></ul>
  6. 6. FITTING PROCEDURE <ul><li>Keratometry </li></ul><ul><li>Trial Set :- </li></ul><ul><ul><li>Diameter – 7 to 9 mm (.05 mm interval) </li></ul></ul><ul><ul><li>Base curve – 7 to 8.4 mm </li></ul></ul><ul><ul><li>Central thickness - .1 to .2 mm </li></ul></ul><ul><ul><li>Power +/- 25 D </li></ul></ul>
  7. 7. DIAMETER <ul><li>Corneal diameter & palpebral aperture </li></ul><ul><li>9 mm </li></ul>
  8. 8. BASE CURVE <ul><li>Mean of the two K reading </li></ul><ul><li>Flatter K </li></ul><ul><li>Flatter than K – spherical cornea </li></ul>
  9. 9. POWER <ul><li>L.P. – Lens power </li></ul><ul><li>B.V.P. – Back vertex power </li></ul><ul><li>.25 D for every .05 mm change in radius </li></ul><ul><li>More – as radius is steepened </li></ul>
  10. 10. INSERTION & REMOVAL OF LENS
  11. 11. CENTRATION OF LENS
  12. 12. BLUE LIGHT SOURCE
  13. 13. FL STAIN
  14. 14. FLAT LENS STEEP LENS
  15. 15. TORIC CORNEA
  16. 16. IDEAL PATTERN FALSE PATTERN
  17. 17. HYGIENE <ul><li>Preservative & anti bacterial </li></ul>
  18. 18. PROBLEMS <ul><li>Tight fit : </li></ul><ul><ul><li>Little movement </li></ul></ul><ul><ul><li>FL patterns </li></ul></ul><ul><ul><li>Removal difficult </li></ul></ul><ul><li>Remedy : </li></ul><ul><ul><li>Flat </li></ul></ul><ul><ul><li>Small Lens </li></ul></ul>
  19. 19. LOOSE LENS <ul><li>Flat lens </li></ul><ul><li>Too much movements </li></ul><ul><li>FL pattern </li></ul><ul><li>Remedy : </li></ul><ul><ul><li>Steep lens large, lens </li></ul></ul>
  20. 20. LOW RIDING LENS <ul><li>Thick Heavy plus </li></ul><ul><li>Remedy </li></ul><ul><ul><li>Large, flat, lenticular lens </li></ul></ul><ul><li>High riding lens </li></ul><ul><ul><li>Thin – lens </li></ul></ul>
  21. 21. High riding lens Low riding lens
  22. 22. Side version
  23. 23. Hz. Displaced lens <ul><li>Astigmatism </li></ul><ul><li>Remedy-Steeper lens </li></ul>
  24. 24. WARPAGE <ul><li>Rough Handling </li></ul><ul><li>Excessive pressure during cleaning </li></ul>
  25. 25. <ul><li>Thank you </li></ul>

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