Keratoconus Treatment Update Dr Ian Chan Hollywood Medical Centre Nedlands T 93881828 F 93881868 E [email protected] o 1 in 2000 (1in 400) o Affects mainly young people o Disease is progressive until around 45 years of age o Significant impact on a patient’s productivity even with moderate disease o Severe disease can cause disability Keratoconus Treatment Options Vision • Stabilisation Spectacles • Rigid Contact Lenses • Intracorneal Ring Segments • Topographic Guided Laser Keratectomy • Implantable Contact Lens • Corneal Transplant • Collagen Cross-linking • Corneal Transplant Collagen Cross-Linking (CXL) o o o o o Industrial collagen cross-linking can improve material strength KC stop progressing with age Riboflavin excited by UV to product oxygen radicals covalent cross-linking bonds In-vitro experiments in 1997 • 300% increase in rigidity Human trial in 2003 CXL clinical experimental results • over 10 years experience • over 300 papers on case series • 3 randomised controlled trials • • Largest and longest duration RCT from REEVH • 94 patients for 3 years up to 6 years of followup data CXL clinical experimental results • Overall: • Stop KC progression long term in 95% of patients • Around 1 diopter of reduction in Keratometry • Around 1 line of gain in UCVA and BSCVA Personal CXL clinical results • 315 cases • Only 1 case required retreatment • 1 case progressed to corneal transplantation • 1.6 diopter of reduction in Keratometry • Around 1.5 line of gain in BSCVA • 1 case of scarring • No keratitis Standard CXL Protocol • 7 to 9 mm diameter of epithelium detachment • 5 to 30 minutes of 0.1% riboflavin isotonic solution • 30 minutes of 370nm UVA at 3mW/cm2 • Bandage Contact Lens • Antibiotic and Steroid drops Typical CXL experience • Some discomfort in first 3 days • Reduction in vision for 1-2 weeks • Reduction in contrast for 1 to 2 months • Complication rate is very low • Some improvement in vision is noted either early or later • Improvement is still possible up to 3 years later New trends in CXL treatment • Higher Fluence CXL • • Epithelium-On Treatment • • Reduction in recovery time and complications Hypotonic Riboflavin Solution • • Reduction in treatment time Enable treatment for thinner corneas Combined with laser keratectomy and implantable ring segment • Improve visual outcome CXL summary • It does work • Stabilise disease in majority of Patients • Minimal risk • Mild improvement of disease • Early Diagnosis is now important Intra-Corneal Ring Segments (ICRS) Implantable Corneal Ring Segments (ICRS) • Kerarings, Ferrara Rings, INTACS • Over 10 years of experience • Numerous papers published • Average effect • • 3 diopter of flattening • 1.5 diopter of astigmatism reduction • 3 lines of UCVA improvement • 3 lines of BSCVA improvement • up to 5% can lose BSCVA Adverse effects - glare, keratitis, extruded segments, doesn’t stop disease progression ICRS • Also proven to be effective • Improves vision in some patients • Reversible • Most patients still require spectacles • Does not stop progression Topographic Guided PTK Topographic Guided Laser Keratectomy • Custom ablation of the cornea based on topographic data • Always performed together with CXL in Keratoconus • Less than 50 micron ablation • Long Term results after 36 months of 231 eyes shows no disease progression and cornea continues to flatten • The thinnest cornea was just over 300 micron before treatment 195 after treatment!! Topographic Guided Laser Keratectomy • • Overall results: • over 3 lines gain in UCVA • 2 lines gain in BSCVA Adverse effects: longer recovery, scarring Topographic Guided PTK • So far appears to be effective and safe • Caution required • Most patients still require spectacles • Compared to ICRS • Disadvantage: Irreversible, limited by corneal thickness • Advantage: Both vision improvement and stabilisation treatments all done on the same day. Corneal Transplant Corneal Transplantation • One of the most successful form of tissue transplantation • The majority of patients can reach driving level vision • Disadvantages are • • Long recovery - up to 3 year to reach stability • May need another graft in a lifetime • Risk of rejection always present Newer forms of keratoplasty lowers the rejection and failure risk Summary • None of these treatments can perfectly reverse Keratoconus • Early diagnosis is very important - we can now stop it • Every keratoconus patient is different - important to customise treatment to address their vision and stabilise disease • RGP is still the quickest and most effective way to improve vision • ICRS and Topographic PTK is a good option for improving vision in CL intolerant patients • Disease stabilisation is paramount - CXL does work and it is evolving • Corneal transplant is still a great option when all else fails Case Topo PTK and ICRS for KC • 41 yo female • Long standing Keratoconus and high myopia • Unable to tolerate RGP any more after many years of lens wear • BSCVA R 6/12- L 6/24 • R Ferrara Ring • improved R to 6/9 with -18 soft contact • Glare and reflections at night Case Topo PTK and ICRS for KC • L Topographic guided PTK • With -18 SCL • R 6/9-2 L 6/9 • No Glare from LE • Day time contrast slightly better with RE • ? 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