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Keratoconus & it’s management (kunj).pptx
- 1. ~ Kunjvihari Yadav (Optometry intern at UPUMS, Saifai, Etawah, UP)
- 2. Introduction From Greek Kerato= Cornea Conus = Cone-shape Definition - keratoconus is a degenerative non-inflammatory disease of the cornea where the central or paracentral cornea undergoes progressive thinning , changing it from dome-shaped to cone shape , causing irregular astigmatism.
- 4. Onset of keratoconus It can be anywhere between the ages of 8 and 45. In the majority, it becomes apparent between the ages of 16 and 30 years . It affects male and female equally . KC is present in both eyes in over 90% of cases. Onset is not always at the same time or to the same magnitude . KC is has been associated with conditions such as- • Hay fever • Asthma • Eczema • Down’s syndrome • Marfan’s syndrome etc.
- 5. Etiology Still unknown. The incidence of KC reported to be 1 in 2000 people Heredity- there is less than one in ten chances that a blood relative of keratoconic patient will have KC. Eye rubbing- especially children due to some diseases as vernal keratoconjunctivitis . So corneal curvature will be changed . Eye rubbing among keratoconic patient has been reported 66% to 73% . Hormonal change - that KC is often first develops around puberty. Or advances during pregnancy. Contact lens wearer- uncorrect fitting.
- 6. Classifications Based on severity of curvature - • Mild: <45.00D • Moderate: 45.00D to 52.00D • Advanced: 52.00D to 62.00D • Severe: >62.00D Based on shape - • Nipple cones: cone small size 5mm • Oval cones: larger ellipsoid 5-6mm • Globus cones: largest>6mm, may involve over 75% of cornea
- 7. Nipple cone Oval cone Globus cone • Diameter: <5mm • Cone: lies in centre towards inferior nasal quadrant • Easiest to fit with CL • Diameter: >5mm • Cone: displaced inferiorly • More difficult to fit with CL • Diameter: >6mm • Cone: steepening • 75% affected cornea • Most difficult to fit with CL
- 9. The classic signs of KC Corneal nerves: • More prominent then in normal eye. Vogt’s striae: • Fine vertical line in the stroma and Descemet’s membrane. • disappear temporarily on digital pressure. Fleischer’s ring: • Iron pigment ring forms the base. • May be partial or complete.
- 10. The classic signs of KC Corneal thinning: • Represents an actual reduction in the number of stromal lamellae. Munson’s sign: • Ectasic protrusion of the cornea on down gaze produces a V-shaped conformation of the lower lid. Rizzuti sign: • Lateral illumination of the cornea produces a steeply focused beam of light near the limbus.
- 11. Corneal scarring: • Sub-epithelial corneal scarring. • Not generally seen early. • May occurs as keratoconus progresses because of ruptures in bowman’s membrane which is then filled with connective tissue. Corneal hydrops: • Occurs generally in advanced cases, when Descemet’s membrane rupture, aqueous flows into the cornea and reseals.
- 12. Diagnosis Diagnosing keratoconus in its early stages is more difficult . It requires a through history and examination . • Visual acuity – Reduced visual acuity due to oblique astigmatism. • Retinoscopy – scissor reflex • Keratometer- distorted mires • Ophthalmoscopy – oil droplet • Reduced intraocular pressure- due to corneal thinning or reduced scleral rigidity.
- 13. • The topography of keratoconus – the photokeratoscope or placido disc can provide an overview of the cornea and can show the relative steepness of the corneal area. Photokeratoscope with normal round curvature Distorted pattern of the rings.
- 14. Nipple-Shaped Topography Small near central ectasia, less than 5.0 mm in cord diameter . May manifest as a small central ectasia with moderate to high with-the-rule corneal astigmatism.
- 17. Management of kc Spectacles- • Mild keratoconus in early stage can be corrected with spectacles. • As the cornea steepens and becomes more irregular , glasses not capable of providing adequate visual improvement.
- 18. Contact lenses - • Soft contact lenses. • Rigid gas permeable lenses. • Combined lens system- 1. Piggy back system 2. Hybrid lens system • Fully keratonic designed lenses- 1. Rose k 2. Scleral and mini scleral lens
- 19. soft contact Lenses - • It is not better than spectacle lens but it works in piggy back system . • At very stage, this way work as equal to spectacle . • But patient may not be satisfied with the level of vision he has even though it is 6/6- • Shadow effect of texts • Ghosting of image • Poor night vision • Eye fatigue on prolong reading
- 20. Rigid Gas Permeable Lenses - • Cost effective , easily available , suitable for mild to moderate keratoconus . • Fitting: three point conventional fitting philosophy.
- 21. combined lens system - Piggy back system- Rigid lens fitted over a hydrogel lens increases comfort resulting in adequate wearing time with good vision .
- 22. combined lens system - hybrid lens system – One way to overcome the problems with piggyback lenses, yet have the optics of a rigid lens with the comfort of a hydrogel , it is to fuse a soft rim onto a hard central portion .
- 23. fully keratoconic designed lens - • Rose K: • Scleral lenses
- 24. Surgical intervention- Collagen cross- linking (CXL or C3- R): It may slow or halt the progression of keratoconus by using a photo-oxidative treatment to increase the rigidity of the corneal stroma .
- 25. Keratoplasty • For patients intolerant to contact lens and cases with scarring. • Penetrating keratoplasty and Deep anterior lamellar keratoplasty can be done . Penetrating keratoplasty: In this procedure , the central area of the cornea is excised and a full- thickness corneal button is sutured into the recipient
- 26. Lamellar keratoplasty: A partial thickness portion of the cornea is excised and a partial thickness donor corneal button is sutured into the recipient transplant .
- 27. Intacs: intrastromal corneal ring – Two arc shaped segments of inert plastic are inserted into the peripheral (outer) cornea. These segments add volume to the thinned area . This flattens the steep curvature and reduces the irregular shape.
- 28. STEPS IN KERATOCONUS TREATMENT KERATOCONUS PROGRESSIV E NON PROGRESSIVE SPECTACLE S CONTACT LENSES CXL CORNEAL SCLERAL INTACT S CORNEAL TRASPLANT S PHAKIC IOLS ACCELARAT ED CXL SURGICAL OPTIONS SCLERAL LENSES ARE THE BEST CHOICE FOR KERATOCONUS