Dr. Mohammad Amiri , ODDepartment of Optometry ,Faculty ofRehabilitationShahid Beheshti Medical Sceince UniversityVision C...
Keratoconus• Is a progressive disorder in which the cornea has irregular  shape• Onset: around puberty• Autosomal dominant...
• According to  morphology can be  classified into• Nipple cones: small size  5mm; steep curvature;  the apex of the cone ...
• Oval cones: 5-6mm size;  ellipsoid (oval) &  displaced  inferotemporally
• Globus cones: the  largest >6mm
• Presentation: visual impairment due to progressive myopia & astigmatism  (usually reported for one eye); changes in spec...
Vogt striae (i.e. line) in keratoconus
Munson sign in keratoconusLate in the disease:  Munson sign (i.e.  bulging of the lower lid  on downgaze); visual  acuity ...
Keratoconus• What have the years taught us?
Keratoconus CharacteristicsNon-inflammatory.Central or para-central corneal thinning.Corneal steepening or protrusion....
Keratoconus• Non-Inflammatory Ectasia   •   Stromal Thinning   •   Disruption of Bowman’s       Membrane• Corneal Ectasia ...
Keratoconus• Demographics  •   Estimates vary from 50 to 170      per 100,000• Obscure Etiology  •   Heredity  •   Allergi...
Why Does the Cornea Bulge in             Keratoconus?• Corneal tissue is  abnormal   •   Too elastic?   •   Abnormal cross...
Pathology of Keratoconus Loss of Bowman’s Layer. Stromal Thinning. Apoptosis. Increased Enzyme Activity. Enlarged Pro...
Causes of Keratoconus• Heredity vs. Mechanical• Cellular• Tissue• Genetic
Cellular Changes• Keratoconus cells are hypersensative.• Increased enzyme activity, lack of enzyme  inhibitors.• Matrix su...
Tissue Changes Loss of Bowman’s layer. Lamellar slippage. Lack “anchoring” lamellar fibrils. Apoptosis of the stroma c...
Heredity vs. Mechanical• Does eye rubbing cause Keratoconus?• 2 out of 250 doctors feel that rubbing is a  cause.• KC pati...
Genetics• Autosomal dominant w/variable penetrance.• SOD1, an antioxidant enzyme, is abnormal in  some KC corneas.• No sin...
Additional InformationMale to Female Ratio = 3:1Approximately 20% result in PKP.90% are diagnosed by optometrists.Mean...
Progression and PrognosisAge is a big factor.The younger the diagnosis, the poorer the prognosis.Less likely to progres...
Possible Aggravating Factors• UV exposure.• Allergies.• Vigorous eye rubbing.• Poorly fitting contact lenses.• Inflammation.
Types of Keratoconus• Nipple/Oval cone - central or mildly para-  central localized thinning and steepening.• Keratoglobus...
Nipple/Oval Cone• Central Steepening• Steepest form
Keratoglobus• Wider – 75 to 90% of cornea.• Not as steep.
Pellucid Marginal Degeneration• Peripheral Thinning
Orbscan Analysis
How to Treat Keratoconus Spectacles Contacts     Soft Standard     Soft Custom     RGP Standard     RGP Custom     ...
When to Intervene?• Best Spectacle/Soft CL Acuity 20/30 or better?  – Good tolerance of acuity.  – Corneal health is not c...
Which RGP Design?• Early Keratoconus  – Standard RGP  – KC RGP• Mid-stage Keratoconus  – KC RGP  – Custom KC RGP• Advanced...
My “GO TO” Lens – Rose K• Developed by Dr. Paul Rose.• Designed to fit the irregular cornea.• “Very forgiving lens”• Multi...
Nipple/Oval Cone Fitting•   Most common form of KC.•   Early stages - simple RGP or KC RGP•   Later stages – KC RGP usuall...
Rose K2• Rose K vs. Rose K2• 72% of patients notice an increase in acuity  with aspheric, aberration control.• Lens to be ...
Fitting the Rose K2• Too high – tighten edge lift  reduce OAD  steepen base curve• Too low – increase edge lift  increase ...
Fitting the Rose K2• Centrally fitting the  lens on a nipple  cone better insures  optimal acuity and  comfort.
Rose K2IC•   IC stands for irregular cornea•   Larger diameter•   Larger optic zone•   Aspheric for aberration control•   ...
• PMD• Keratoglobus• LASIK induced ectasia• Corneal transplants
Corneal DystrophiesTraumatic Corneas with ScarsPost RKIrregular Astigmatism or Corneal Warpage
What is That?
Asymmetric Corneal Technology• ACT.
ACT – Continued…
Fitting with ACTUsing ACT ( Asymmetric Corneal Technology)  • 3 standard grades available  • Option also to specify degree...
Fitting with ACTACT - Improved comfort , lens stability and vision          NO ACT                    WITH ACT
Toric Peripheral Curves
Fitting Pearls Tendency to tighten after initial fitting. Light central touch will increase acuity. Avoid central stain...
Penetrating Keratoplasty                   When to refer? Acuity is 20/50 or worse. Patient intolerance to visual decrea...
Post PKP Management• How soon can you fit with lens?• Why are the curvatures so strange?• Do you have to wait for all sutu...
Rose K2 Post Graft
PKP Topography
Rose K2 Post Graft Much more difficult to fit than KC. Patients are less tolerable to CL. Eyes are more dry. Ill-fitti...
K2PG Fitting Pearls•   Don’t be intimidated!•   Watch tear flow!•   Also good lens for ectasia patients.•   Stay with your...
Post Graft – Too Steep
Post Graft – Too Flat
Post Graft – Good Fit
Watch Vasculature
The Difficult Ones• Nothing is comfortable.• Acuity isn’t improving..• Eyes are too dry. (Sjogren’s Syndrome)• Cornea is t...
What Do You Do?
Rosek2 part1
Rosek2 part1
Rosek2 part1
Rosek2 part1
Rosek2 part1
Rosek2 part1
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  • Thank Elliott and Lee.Introduction
  • Lawrence Gallomp
  • 1- Epithelial cells seem to be in direct contact with stroma.2- In central and/or inferior cones, stroma can be less than ½ that of normal stroma. Epithelium 2-3 cell layers thick.3- Programmed cell death. Greater apoptosis in the anterior stroma. Repetative injury to epithelium stimulating greater apoptosis.4- Decreased presence of enzyme inhibitors.
  • 2 doctors out of 250 still felt that KC was caused by eye rubbing. KC patients may indeed rub their eyes more than most, but maybe there is something about KC that makes them feel like they
  • Difficult for transplantation.
  • Generally works for all types of RGP’s and corneas.
  • It is recommended that you fit the central base curve first and then make and adjustments to the diameter and edge.
  • Rosek2 part1

    1. 1. Dr. Mohammad Amiri , ODDepartment of Optometry ,Faculty ofRehabilitationShahid Beheshti Medical Sceince UniversityVision Care of MeniconKeratoconusAnd specialty contact lens fitting of irregularcorneas
    2. 2. Keratoconus• Is a progressive disorder in which the cornea has irregular shape• Onset: around puberty• Autosomal dominant• Usually bilateral; but assymetrical• Systemic association: e.g. Down syndrome; Turner syndrome; Marfan syndrome• Ocular association: e.g. retinitis pigmentosa; vernal keratoconjunctivitis;
    3. 3. • According to morphology can be classified into• Nipple cones: small size 5mm; steep curvature; the apex of the cone is central or infero-nasally
    4. 4. • Oval cones: 5-6mm size; ellipsoid (oval) & displaced inferotemporally
    5. 5. • Globus cones: the largest >6mm
    6. 6. • Presentation: visual impairment due to progressive myopia & astigmatism (usually reported for one eye); changes in spectacle Rx; decrease tolerance to contact lens wear;• Signs: central or paracentral stromal thinning; apical protrusion; irregular astigmatism; steepening of the cornea graded according to keratometry readings (mild <48D, moderate 48-54D, severe >54D) Early in the disease: oil droplet reflex on ophthalmoscopy; irregular scissor reflex on retinoscopy; Vogt lines (i.e. deep vertical stromal striae) on slit- lamp exam; irregular astigmatism on keratometry; abnormal corneal topography
    7. 7. Vogt striae (i.e. line) in keratoconus
    8. 8. Munson sign in keratoconusLate in the disease: Munson sign (i.e. bulging of the lower lid on downgaze); visual acuity worsens; watering; oedema; stromal scarring after beaks healing;
    9. 9. Keratoconus• What have the years taught us?
    10. 10. Keratoconus CharacteristicsNon-inflammatory.Central or para-central corneal thinning.Corneal steepening or protrusion.Increased astigmatism and possibly myopia.Loss of best spectacle corrected visual acuity.Corneal striae and scarring.Corneal hydrops (inflammatory).
    11. 11. Keratoconus• Non-Inflammatory Ectasia • Stromal Thinning • Disruption of Bowman’s Membrane• Corneal Ectasia • Myopia • Irregular Astigmatism• Optical Correction • Spectacles– early • Contact Lenses– later
    12. 12. Keratoconus• Demographics • Estimates vary from 50 to 170 per 100,000• Obscure Etiology • Heredity • Allergies, Eye Rubbing
    13. 13. Why Does the Cornea Bulge in Keratoconus?• Corneal tissue is abnormal • Too elastic? • Abnormal cross-linking of collagen?• Loss of structural integrity of Bowman’s Layer?• Keratocyte apoptosis • Trauma (eye rubbing)• Corneal tissue bulges because it is too thin?
    14. 14. Pathology of Keratoconus Loss of Bowman’s Layer. Stromal Thinning. Apoptosis. Increased Enzyme Activity. Enlarged Prominent Corneal Nerves.
    15. 15. Causes of Keratoconus• Heredity vs. Mechanical• Cellular• Tissue• Genetic
    16. 16. Cellular Changes• Keratoconus cells are hypersensative.• Increased enzyme activity, lack of enzyme inhibitors.• Matrix substrate instability in response to environmental stress factors.• mtDNA damage and exaggerated oxidative response causing cellular damage.
    17. 17. Tissue Changes Loss of Bowman’s layer. Lamellar slippage. Lack “anchoring” lamellar fibrils. Apoptosis of the stroma causing anterior thinning.
    18. 18. Heredity vs. Mechanical• Does eye rubbing cause Keratoconus?• 2 out of 250 doctors feel that rubbing is a cause.• KC patients do rub their eyes more often than those without KC.• What is it that makes KC patients rub their eyes?
    19. 19. Genetics• Autosomal dominant w/variable penetrance.• SOD1, an antioxidant enzyme, is abnormal in some KC corneas.• No single gene responsible.• 10 different chromosomes have been associated with KC.• Most likely multiple genes involved.
    20. 20. Additional InformationMale to Female Ratio = 3:1Approximately 20% result in PKP.90% are diagnosed by optometrists.Mean age of diagnosis is 22.88 years.Visual outcome with RGP is better than PKP.More prevalent in certain ethnic groups (4x higher in Asians from Indian sub-continent regions than White Europeans).
    21. 21. Progression and PrognosisAge is a big factor.The younger the diagnosis, the poorer the prognosis.Less likely to progress to the point of a transplant if diagnosed in the 30’s.20% of Keratoconus patients result in corneal transplants.35 to 45% of all transplants are due to Keratoconus.
    22. 22. Possible Aggravating Factors• UV exposure.• Allergies.• Vigorous eye rubbing.• Poorly fitting contact lenses.• Inflammation.
    23. 23. Types of Keratoconus• Nipple/Oval cone - central or mildly para- central localized thinning and steepening.• Keratoglobus - Large generalized thinning and steepening.• PMD (pellucid marginal degeneration) – peripheral thinning and steepening.• Keratoconus Fruste – Less progressive and less manipulative.
    24. 24. Nipple/Oval Cone• Central Steepening• Steepest form
    25. 25. Keratoglobus• Wider – 75 to 90% of cornea.• Not as steep.
    26. 26. Pellucid Marginal Degeneration• Peripheral Thinning
    27. 27. Orbscan Analysis
    28. 28. How to Treat Keratoconus Spectacles Contacts  Soft Standard  Soft Custom  RGP Standard  RGP Custom  Hybrid Surgery  Intacs  Penetrating Keratoplasty Riboflavin/UV treatment
    29. 29. When to Intervene?• Best Spectacle/Soft CL Acuity 20/30 or better? – Good tolerance of acuity. – Corneal health is not compromised. – “If it aint broke, don’t fix it.”• Best Spectacle/Soft CL Acuity worse than 20/30? – Specialized contact lenses. – My opinion, use RGP lenses.
    30. 30. Which RGP Design?• Early Keratoconus – Standard RGP – KC RGP• Mid-stage Keratoconus – KC RGP – Custom KC RGP• Advanced Keratoconus – Custom KC RGP – Intra-limbal or Scleral RGP
    31. 31. My “GO TO” Lens – Rose K• Developed by Dr. Paul Rose.• Designed to fit the irregular cornea.• “Very forgiving lens”• Multiple designs to fit all shapes of corneas and corneal conditions.• Blanchard is very good to work with and has staff to assist with very difficult cases.
    32. 32. Nipple/Oval Cone Fitting• Most common form of KC.• Early stages - simple RGP or KC RGP• Later stages – KC RGP usually small and steep.• The steeper the cone, the smaller the lens diameter.
    33. 33. Rose K2• Rose K vs. Rose K2• 72% of patients notice an increase in acuity with aspheric, aberration control.• Lens to be centered on the cone.• Reduce excessive movement (1 to 2mm).
    34. 34. Fitting the Rose K2• Too high – tighten edge lift reduce OAD steepen base curve• Too low – increase edge lift increase OAD flatten base curve
    35. 35. Fitting the Rose K2• Centrally fitting the lens on a nipple cone better insures optimal acuity and comfort.
    36. 36. Rose K2IC• IC stands for irregular cornea• Larger diameter• Larger optic zone• Aspheric for aberration control• Reverse geometry design
    37. 37. • PMD• Keratoglobus• LASIK induced ectasia• Corneal transplants
    38. 38. Corneal DystrophiesTraumatic Corneas with ScarsPost RKIrregular Astigmatism or Corneal Warpage
    39. 39. What is That?
    40. 40. Asymmetric Corneal Technology• ACT.
    41. 41. ACT – Continued…
    42. 42. Fitting with ACTUsing ACT ( Asymmetric Corneal Technology) • 3 standard grades available • Option also to specify degree of tuck in 0.1 steps from 0.4 to 1.5mmGrade 1 ( 0.7mm steeper) Grade 3 (1.3mm steeper) Grade 2 (1.0mm steeper)
    43. 43. Fitting with ACTACT - Improved comfort , lens stability and vision NO ACT WITH ACT
    44. 44. Toric Peripheral Curves
    45. 45. Fitting Pearls Tendency to tighten after initial fitting. Light central touch will increase acuity. Avoid central staining. Movement is necessary but slight movement is usually sufficient. Pay attention to tear flow beneath lens. The steeper the lens, the smaller OAD and less movement. Don’t change too many parameters at once.
    46. 46. Penetrating Keratoplasty When to refer? Acuity is 20/50 or worse. Patient intolerance to visual decrease. Scars within the visual axis. Multiple episodes of Hydrops. Contact lens intolerance. Unable to get adequate/healthy CL fit. Consider OD to OD referral. Give reasonable expectations.
    47. 47. Post PKP Management• How soon can you fit with lens?• Why are the curvatures so strange?• Do you have to wait for all sutures to be removed?• Corrective options. – Spectacles – RGP contact lenses. – LASIK
    48. 48. Rose K2 Post Graft
    49. 49. PKP Topography
    50. 50. Rose K2 Post Graft Much more difficult to fit than KC. Patients are less tolerable to CL. Eyes are more dry. Ill-fitting contact lenses can lead to graft rejection. Lens design is crucial to success.
    51. 51. K2PG Fitting Pearls• Don’t be intimidated!• Watch tear flow!• Also good lens for ectasia patients.• Stay with your fitting basics – Fit base curves. – Adjust diameter. – Adjust peripheral curves. – Use ACT or Toric PC if needed.
    52. 52. Post Graft – Too Steep
    53. 53. Post Graft – Too Flat
    54. 54. Post Graft – Good Fit
    55. 55. Watch Vasculature
    56. 56. The Difficult Ones• Nothing is comfortable.• Acuity isn’t improving..• Eyes are too dry. (Sjogren’s Syndrome)• Cornea is too irregular for any lens to fit properly or in a healthy manner.
    57. 57. What Do You Do?
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