Keratoconus managment

  • View

  • Download

Embed Size (px)


Keratoconus disease

Text of Keratoconus managment

  • 1.Hasan A. Mokbel Contact Lens Department Medicals International

2. What is Keratoconus ? (causes, types, related diseases.) Management of Keratoconus/ available treatment options Rose K family Clearkone 3. Keratoconus is a 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. 4. Tiny fibers of protein in the eye called collagen help hold the cornea in place and keep it from bulging. When these fibers become weak, they cannot hold the shape and the cornea becomes progressively more cone shaped. 5. Classification can be according to : Shape : 1. Nipple Shape ( small size 5 mm) 2. Oval cone ( 5 to 6 mm ) 3. Globus ( large , may involve 75 % of the cornea ) Severity of curvature : 1. Mild ( 45.00D) 2. Moderate (45.00 52.00 D) 3. Severe ( more than 52.00 D) 6. Retinitis pigmentosa a form of retinal dystrophy Micro cornea An abnormally thin and flat cornea Down syndrome genetic disorder caused by the presence of all or part of a third copy of chromosome 21 Irregular Astigmatism 7. Surgical & non-surgical treatment are available. 1. Surgical treatment includes : Intacts ( intrastromal corneal ring segments ) Corneal transplant phakic IOL 2. Non surgical treatment : Contact Lenses Collagen Cross linking Spectacles 8. At the early stages of Keratoconus spectacles and soft lenses are used to correct vision. With the progression of the disease majority of the patients will use rigid contact lens. The very latest contact lens for treating Keratoconus is the synergize hybrid contact lens which is rigid at the middle and soft at the edges. 9. RGP lenses provide good treatment by resurfacing the irregular cornea and corrects astigmatism and provide good vision quality. The majority of patients who used RGP witnessed a dramatic improvement. Patients with contact lenses suffer mainly from uncomfortable long period wear due to dryness of the eye since there's no lubrication to prevent evaporation. 10. The Rose K lens was invented by Paul Rose, an optometrist from Hamilton, New Zealand. Rose k lenses were made with complex geometry to fit any type of cone shape cornea. The Rose K family includes : 1. Rose K/K2 2. Rose K2 post graft 3. Rose K2 IC 4. Rose K2 XL 11. The optical zone is reduced to fit the cone and the peripheral curve is designed to fit the rest of the irregular cornea. Lenses can be customized to suit each eye and can correct the myopia and astigmatism associated with the condition. 12. The Rose K lens has a number of features that make it ideal for Keratoconus: 1. Its complex geometry can be customized to suit each eye and can correct all of the myopia 2. They are easy to insert, remove and clean. 3. They provide excellent health to the eye, because they allow the cornea to "breathe" oxygen directly through the lens. 4. Practitioners have the Rose K trial set fitting system which achieves a first fit success in over 80% of patients internationally. 5. They correct myopia and astigmatism associated with Keratoconus. 13. Rose K2 is a refined Rose K lens which takes into account the unusual corneal shapes of Keratoconus patients, which require abnormal curves on the back of the lens to fit the cornea optimally. The Rose K2 lens minimizes these aberrations by applying very small changes to the curves on both the front and back of the lens in an attempt to bring the light passing through the lens within the pupil zone to a single point. 14. Easy fitting Large parameter range available which makes fitting easier and lowers the chair time. Advanced aberration control Increased comfort 15. Indications : Pellucid Marginal Degeneration - PMD Keratoglobus more than 75% of cornea is involved in the irregular shape Post Lasik,Post Graft 16. Same design as RoseK2 IC , reduced pool and reversed curves to allow proper healing after surgery. Rose K Post Graft Lens for patients who have undergone penetrating keratoplasty. This lens is designed for postoperative recovery and improvement in vision. 17. semi-scleral contact lens designed to vault the corneal surface and rest on the less sensitive surface of the sclera, these lenses often are more comfortable for a person with Keratoconus. Also, scleral lenses are designed to fit with little or no lens movement during blinks, making them more stable. Indicated for indicated for Keratoconus, PMD, Post Graft, and other irregular cornea conditions that cannot be successfully fitted within the limbus. much larger than conventional GP lenses and rest near the junction between the cornea and the sclera. 18. 1. Determine the corneal shape 2. Central fit 3. Peripheral fit 4. Overall diameter 5. Location 6. Lens movement 7. Power 19. Lens selection with a back central optic radius ( BCOR) 0.2 mm steeper than the mean K reading. Central fit : leather weight touch to the apex of the cone is desirable. Peripheral fit : the peripheral fit should have a Fluorescein edge width 0.5 0.7 mm 20. Overall diameter : the standard diameter is 8.7 mm but smaller diameter can be used with steep cornea ( higher grade of Keratoconus) Location of the lens should be maintained centrally ( any dislocation can be corrected by changing diameter , edge lift and back central optic radius (BCOR) 21. Lens movement with every blink the lens should move freely across the cornea then returns to its position and rests. Determine the lens power by a carful over refraction +/- 1.00 D and refine by 0.5 and 0.25 D. 22. Vaults the irregular corneal forms ClearKone combines the best of both worlds the crisp vision of a high-oxygen rigid RGP contact lens with the all- day comfort and convenience of a soft lens. 23. The ClearKone fitting approach called vaulting allows doctors to simply increase the depth of the contact lens over the cornea depending on how steep or severe the individual patients Keratoconus is. The ClearKone vault system comes in 11 different choices and therefore can accommodate even the most severe forms of Keratoconus. 24. Steps of fitting : 1. Vault selection 2. Skirt selection 3. Determine Lens power 25. 1. Vault selection : Begin with 250 Vault value in Medium skirt curve Insert the lens filled to the top with saline and a drop of high molecular weight Fluorescein. Check for central bearing ,central pooling , or for bubbles. 26. If central bearing is present then increase the vault by 100 [ vault is too low ] If central pooling is present then decrease the vault by 100 [ vault is too high ] 27. 2. Skirt Selection : Always start with the medium skirt curve The lens will exhibit movement very similar to a soft lens The ideal fit will show thinning at the ILZ ( inner landing zone ) and bearing in the OLZ (Outer Landing Zone) 28. 3. Determine Final Lens Power: If the over-refraction is greater than 4.00D adjust for vertex distance