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Update on Keratoconus Diagnosis and Treatment

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Presentation on theme: "Update on Keratoconus Diagnosis and Treatment"— Presentation transcript:

1 Update on Keratoconus Diagnosis and Treatment

2 “Keratoconus is a clinical term to describe a condition in which the cornea assumes a conical shape because of thinning and protrusion” SCLAFANI

3 Keratoconus History Blurred vision Distortion Photophobia
Monocular polyopia Halos Patient presents with frequent eyeglass changes SCLAFANI

4 KCN HISTORY Non-inflammatory 1/2000-5000 Central 2/3 AR/AD Inheritance
Females =Males Presents initially at puberty & progression varies, stability in 30s SCLAFANI SCLAFANI-KCNUpdate

5 “Why don’t we see elderly patients with keratoconus”
Do they die younger NO Do they not visit POSSIBLE Have they CE/PKP POSSIBLE THEORY BY KRACHMER The eye becomes more rigid as the patient ages and therefore the condition stabilizes SCLAFANI

Vernal KC Atopic Dermatitis Down’s Syndrome Floppy Eyelid Syndrome Mitral Valve Prolapse Ehlers-Danlos Syndrome Osteogenesis Imperfecta Lawrence-Moon-Biedl Syndrome Neurofibromatosis Psuedoxanthoma Elasticum SCLAFANI

7 ETIOLOGY OF KCN History of trauma that causes weakness
Recurrent trauma due to rubbing from Blepharitis, CL/lids, 53% have atopic dx Inflammatory component !!! Decrease proteinase inhibitors Increase collagenase Premature keratocytic apoptosis Increase cytokine binding SCLAFANI

8 Basic Science Research
KCN have higher # of mitochondrial DNA deletions that leads to decrease oxidative phosphorylation… increase H202 Causes leakage, damages proteins, and results in oxidative stress Leads to apoptosis, abnormal healing, inflammation. SCLAFANI

9 Basic Science Research
Yaron Rabinowitz, MD UCLA KCN have suppressed Aquaporin 5 (AQP5) AQP5 is the water transport gene that is responsible for cell migration and wound healing. Quantitative PCR testing (epithelial cells) could diagnose this SCLAFANI

KCN is unlikely a single gene defect Chromosome 5, 21 Multiple genes in a common pathway Those with the defect may develop KCN naturally or only if exposed to factors that induce oxidative stress: CL over-wear, UV, allergy or refractive surgery TX: Anti-inflammatory, Anti-oxidant SCLAFANI

11 RETINOSCOPY Scissors Reflex Against motion that breaks apart
Represents multiple refractive powers within the optic zone SCLAFANI







18 Keratoconus- Keratometry
Steepening begins infero-temporally and progresses clockwise TOPOGRAPHY- more sensitive PLACIDO RINGS- get closer SCLAFANI SCLAFANI-KCNUpdate

19 PLACIDO RING IMAGES Rings that are closer together represent areas of steeper curvature May indicate a tight suture applicable SCLAFANI

Predicts the relative elevation or depression of the cornea (in mm) using a computer generated BEST FIT SPHERE as a reference and fit at the steepest point SCLAFANI SCLAFANI-KCNUpdate

+ VALUES- warm colors points higher than sphere = elevation Areas of bearing or touch - VALUES- cool colors points lower than sphere = depression Areas of pooling SCLAFANI SCLAFANI-KCNUpdate

22 PELLUCID MARGINAL Tear meniscus can creates pseudo-PMD SCLAFANI


24 PSEUDOKERATOCONUS Corneal warpage topography can mimic KC
Repeat topography must be performed and a measurable change would indicate pseudo-KC Evaluation of elevation maps at steep zone: Predicts the elevation or depression of the cornea if the best fit sphere was on cornea SCLAFANI SCLAFANI-KCNUpdate


26 KCN Effects on Vision Tim McMahon, OD
60% reduction in VA is due to curvature, not just high cylinder RGP corrects cylinder however HOA remain COMA May consider reverse geometry CLS Reduced low contrast VA Reads chart slower SCLAFANI

27 COMA Z31 Similar to SA except that it concerns off axis peripheral rays that cause a comet-shaped image deformity to non-axial portions of the image. Minimal Post refractive surgery “Potato chip” due to flap hinge and shows the most dynamic change. SCLAFANI

28 Corneal laser refractive surgery: pre-op, enhancement options
Phakic IOLs Corneal refractive implants: Intacs Anterior Segment Imaging and Surgery Corneal Imaging and Measurement Iris Imaging and Evaluation Trauma Assessment SCLAFANI

29 Visante Applications Anterior Segment Imaging and Surgery
Corneal Imaging and Measurement imaging and evaluation of corneal pathologies penetrating keratoplasty lamellar keratoplasty endothelial keratoplasty keratoconus imaging and assessment anterior segment imaging through opaque corneas SCLAFANI SCLAFANI-KCNUpdate

30 Terrien‘s Marginal Degeneration
SCLAFANI image courtesy of Dr. M. Packer SCLAFANI-KCNUpdate

31 Evolution of KCN: Ectasia to Hydrops
SCLAFANI image courtesy of Prof. G. Baikoff SCLAFANI-KCNUpdate

32 KCN/Open Angle (ML) SCLAFANI

33 KCN- Thinning (ML) SCLAFANI

34 Indications for Intra-Limbal Lenses
KCN RGP dropouts Pellucid Marginal Post-PKP Astigmatic corneas SCL failures: due to neovascularization or poor visual acuity. SCLAFANI SCLAFANI-KCNUpdate

35 Large Diameter Lenses Dyna Intralimbal (Lens Dynamics) Macrolens (C&H)
Jupiter (Innovations in Sight) GBL (Con-Cise) Corneo- Scleral 12.9 mm mm Semi- Scleral 13.6 mm mm Mini- Scleral 15.0 mm-18.0 mm Scleral Bearing, minimum corneal clearance Full Scleral 18.1 mm- > 24+ mm Scleral Bearing, maximum corneal clearance SCLAFANI Robert Breece, OD

36 Intra-Limbal Fitting BC is Flatter than expected Goal
4-5mm temporal vs. Average Mid K +.2mm Goal Light feather touch .2mm < corneal diameter (11.3 OAD) .1-.2 mm movement .2mm edge clearance Menicon Z or Extreme Unique ph or Claris SCLAFANI SCLAFANI-KCNUpdate

Soft Spheres Soft Torics X-cel Flexlens Tricurve Basecurve Diameter Center Thickness .45 dK 13.2 Continental, Gelflex USA, Ocu-Ease (Ocuflex K) SCLAFANI

38 Innovations in Sight SUPER NOVA HydroKone™
Benz 5x material,Glycerol Methacrylate Less dehydration, flexure,better optics Fit the normal peripheral cornea & sclera like standard SCL. The central posterior curve provides sagittal depth to touch POSTERIOR: Steep central curve, flatter paracentral peripheral curve all aspheric ANTERIOR: Central optical surface that quickly tapers to maximize 02 Low riding More movement SCLAFANI

39 Innovations in Sight SUPER NOVA HydroKone™ Base Curves: 4.1 to ( ) Diameters: 12.0 to (14.8) Paracentral: (8.6) Sphere: to Cylinder: to Axis: 1 to 180 in 1 degree steps Mean K + 1mm Do not use H2O2 due to thickness EXPECT MORE MOVEMENT SCLAFANI

40 SynergEyes™ A High Dk Hybrid
Material Paragon HDS 100 GP Center 27% Water Non Ionic Skirt (Group I) Design 14.5 mm over all diameter 8.4 mm rigid center 7.8 mm optic zone 2-4skirt radii choices for each base curve radius Skirt thickness consistent across full power range Engineered edge HyperBond™ junction technology Paragon HDS 100® Rigid Center Non-Ionic 27% water Hydrogel Skirt 8.4 mm 14.5mm

41 SynergEyes KC 3 skirt curve options for fitting flexibility
Prolate ellipsoid base curve Spherical Skirt begins at 9.0 mm diameter 3 skirt curve options for fitting flexibility FDA Clearance December 2005 SCLAFANI

42 Aspheric Base Curve Power Flat Skirt Medium Steep
SynergEyes KC Diagnostic Set Parameters Aspheric Base Curve Power Flat Skirt Medium Steep 5.7mm (59.00) -14.00 8.5 8.2 7.9 5.9mm (57.00) 6.1mm (55.50) -12.00 6.3mm (53.50) -10.00 8.8 6.5mm (52.00) -8.00 6.7mm (50.50) -6.00 6.9mm (49.00) -5.00 7.1mm (47.50) -4.00 9.1 SCLAFANI

43 SynergEyes Fitting Lens Movement .2mm to .3mm movement with blink
Slight lag in upward gaze Free of scleral impingement Free to move on “push up” Free of “edge fluting” SCLAFANI

44 The Fitting Tips Never prescribe Flatter than Flat K
Counter-intuitive: Corneas flatter than 44.25D and larger than 12.0 mm: Steeper Skirt Corneas Steeper 44.25D and smaller than 11.5 mm: Flatter skirt SCLAFANI

45 Identical Apical Radius with Different HVID = different sagittal depth
12.0 mm 3.60 2.96 11.0 mm

Proprietary materials that has a SiHy skirt and higher Dk GP The GP will have less flexure, will likely discontinue the enhanced profile To reduce peripheral crimping, the skirt curves will be multicurve: bi or aspheric CLEAR KONE : Additional KC lens for more ectopic or decentered peaks with reverse geometry to eliminate steep BC SCLAFANI

47 Vault the cornea yet aligns closer to cornea allowing lower powers
Reverse geometry at skirt to allow more tear flow, easier removal SCLAFANI Thanks Rob COurtesy Christine Sindt,OD SCLAFANI-KCNUpdate 47

48 TIPS ON PIGGYBACKS SCL protects from RGP or environment
Reduces epithelial damage due to touch Protects from apical nodules Concurrent EBMD High DK, easily replaced= SiHi Soft Modulus molds to highly toric/steep K +SCL to flatten the RGP - SCL to steepen the RGP fit SCLAFANI

49 Intra-Stromal Rings Ring segments are placed into peripheral corneal channels outside the visual axis to correct low to moderate myopia by flattening the cornea without cutting or removing tissue form the central optical zone FDA approval of Intacs in 1999 for low/mod myopia. Recently approved for keratoconus in US July 2004 Principle benefit: delay or eliminate corneal graft Reversible/Removable SCLAFANI

50 Intacs Studies By Wachler and et al.
74 keratoconus eyes has insertion of intacs with F/U of 9 months 45% gain ≥ 2 lines BCVA (worst pre-opt) 51% had no effective changes 4% loss ≥ 2 lines of BCVA SCLAFANI

51 Single intrastromal corneal implant favored for paracentral cones
Colin Chan, MD and Boxer Wachler,MD Compared 20 eyes (double) vs. 17 (single) Single used .25mm segment/ Double .25&.35 All had paracentral/peripheral cones Significantly better outcomes in change in cylinder, K values, UBVA, BCVA Single 2-3 line gain, Double 1 line gain SCLAFANI SCLAFANI-KCNUpdate

52 Complications of Intacs for KCN
Undercorrection Overcorrection Neovascularization toward the Incision Migration of One segment toward the Wound Extrusion Stromal deposit Flap wrinkling (intracorneal inlays) Epithelial ingrowth Residual refractive error Complication rate ranges from 5-30% SCLAFANI

53 Biomechanical Effect of Combined Riboflavin-UVA
The cross-linking in KCN is abnormal Too elastic and the biomechanical resistance is 50% Loss of Bowman’s Kristen Fry, OD SCLAFANI

54 Biomechanical Effect of Combined Riboflavin-UVA
GOAL: Increase cross-linking Increase diameter 12% Anterior 5% Posterior SCLAFANI

55 C3-R Mechanism UVA 370nm Riboflavin .1% Stability Corneal Collagen
Crosslinking Biomechanical Stiffness Stability SCLAFANI SCLAFANI-KCNUpdate

56 Theo Seiler, MD Initial work AJO, 2003
70% reduction in max K by 2D (N=23) Increase in rigidity by 329% Increase in spacing (1nm) between the collagen molecules leads to increase diameter with no effect on transparency (150nm) Increased resistance to enzymatic digestion Has been shown to be effective for iatrogenic ectasia in animals. Bed < 400 um, severe endothelial damage SCLAFANI

57 PROCESS OF C3R-TX Topical Anesthetic Epithelium is scraped
Acts as diffusion barrier, potential damage .1% Riboflavin drops q 5 min throughout Protects the endothelium, lens, retina Increases absorption into stroma 30 min. radiation 370 nm UVA –3mW/cm3 Post-op FQ and pain relief Depth goes to 300 um therefore must have 400 um pachymetry to protect endothelium SCLAFANI

58 Studies by Eberhard Spoerl, PhD
Immediate Evidence of increased x linking: Resistance to swelling and stretching utilizing Reicherts air pulse deforms cornea and measures area of deformation. Increases anchoring and reduces bulge Cellular Process 24h-12 weeks Leads to apoptosis of keratocytes with late migration of keratoblasts that result in flattening 5 yrs, N = 60, BCVA >1.4 lines K flat 2.87 D SCLAFANI

59 Studies by Aldo Caporossi, MD University of Sienna, Italy
Suggests using it early in the disease to freeze tissue and prevent further ectasia Scrapes the epithelium prior to procedure. 12 eyes followed for 3months in 2004. All showed improved UCVA, BCVA, and reduced steepness- One side effect was transient stromal edema SCLAFANI

60 POTENTIAL USES OF C3R Post-Lasik ectasia Prevent KCN regression/scars
Post CK-to enforce result Post-CRT- to enforce result? epithelial Boxer Wachler, MD has shown this to be an effective treatment when combined with Intacts for KCN SCLAFANI

61 References Colin J, Simonpoli-Velou S. The Management of Keratoconus with Intrastomal Corneal Rings. International Ophthalmology Clinics. 43(3):65-80, Summer 2003. Kaiser P, Friedman N, et. al. The Massachusetts Eye and Ear Infirmary Illustrated Manual of Ophthalmology. Ed Kunimoto D, Kanitkar K, et al. The Wills Eye Manual. Fourth Edition. Lippincott Williams & Wilkins 2004. Roque M, Limbonsiong R, et. al. Myopia, Intracorneal Rings. August 14, Wachler B, Chandra N, et. al. Intacs for Keratoconus. American Academy of Ophthalmology Weissman B, Yeung K, et al. Keratoconus. Jan 29, 2005 SCLAFANI

62 Thank you SCLAFANI

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