LECTURER BIO
CHARISSA YOUNG, OD, FAAO, FSLS
GWCO 2019 - CHARISSA YOUNG, OD, FAAO, FSLS KERATOCONUS 101
KERATOCONUS 101 KERATOCONUS 101
DISCLOSURES COURSE OBJECTIVES
▸ Course sponsored by Valley Contax ▸ Learn what is keratoconus and its impact on the eye and vision ▸ Otherwise no relevant disclosures ▸ Understand special testing related to keratoconus and how it’s diagnosed
▸ Discover what treatment options and patient resources are available
▸ Previous consulting and/or speaking for Allergan and Johnson & Johnson
CLINICAL GUIDELINES FOR KERATOCONUS CLINICAL GUIDELINES FOR KERATOCONUS
KERATOCONUS DEFINITION
▸ A degenerative disease of the cornea that gradually causes it to thin and bulge into a steep cone-like shape CLINICAL GUIDELINES FOR KERATOCONUS CLINICAL GUIDELINES FOR KERATOCONUS
KERATOCONUS EPIDEMIOLOGY - WHO AND WHAT? KERATOCONUS ETIOLOGY
▸ Prevalence ▸ Anatomical changes ▸ ▸ Types Cornea ▸ Stromal thinning
▸ Bowman’s layer breakage
▸ Iron deposit in the epithelium
▸ Sclera
▸ Scleral shape impact (STUDY: View of Correlation of Corneal and Scleral Topography in Cases with Ectasia and Normal Corneas)
CLINICAL GUIDELINES FOR KERATOCONUS CLINICAL GUIDELINES FOR KERATOCONUS
KERATOCONUS ETIOLOGY KERATOCONUS ETIOLOGY
▸ Relation to atopic conditions ▸ Genetics
▸ Correlation to eye rubbing ▸ Correlation to Down Syndrome
CLINICAL GUIDELINES FOR KERATOCONUS KERATOCONUS 101
KERATOCONUS ETIOLOGY KERATOCONUS DEFINITION ▸ Per the AOA: “Keratoconus is a vision disorder that occurs ▸ Reduces risk when the normally round cornea (the front part of the eye) ▸ Smoking becomes thin and irregular (cone) shaped. This abnormal shape prevents the light entering the eye from being focused ▸ Diabetes correctly on the retina and causes distortion of vision.” KERATOCONUS 101 KERATOCONUS 101
KERATOCONUS VISION HOW COMMON IS KERATOCONUS?
▸ Most common corneal dystrophy in the US
▸ Prevalence
▸ 0.05% = 1 in 2,000 in the US (Kennedy et al, 1986)
▸ 0.375% = 375 per 100,000 (Godefrooij, 2017 Netherlands)
KERATOCONUS 101 KERATOCONUS 101
HOW COMMON IS KERATOCONUS? KERATOCONUS ETIOLOGY ▸ Onset usually late teens, 20s ▸ Anatomical changes
▸ Increasing astigmatism ▸ Corneal stroma thins
▸ Progression slows 30s, 40s ▸ Bowman’s layer breakage
▸ Iron deposition in the epithelium
KERATOCONUS 101 KERATOCONUS 101
KERATOCONUS CAUSE AND ASSOCIATIONS KERATOCONUS CAUSE
▸ Possibly genetic ▸ Unknown!
▸ 7% with the condition have family history ▸ Likely combination genetics, environment, ▸ Ethnicity oxidative stress ▸ Eye rubbing / atopic disease
▸ 80% in Keratoconus vs 58% normal eyes
▸ Important to control allergy
▸ Oxidative stress KERATOCONUS 101 KERATOCONUS 101
KERATOCONUS CAUSE KERATOCONUS LESS LIKELY IN…
▸ Differential ▸ Reduced risk associated with smoking, diabetes, age
▸ Post-LASIK ectasia (excessive removal of stromal bed) ▸ Increase corneal cross linking
Foreshadowing treatment corneal cross linking!
KERATOCONUS 101 DIAGNOSIS OF KERATOCONUS
KERATOCONUS ASSOCIATED DISEASES
▸ Eye conditions
▸ Vernal Keratoconjunctivitis
▸ Retinitis Pigmentosa
▸ Retinopathy of Prematurity
▸ Leber’s Congenital Amaurosis
▸ Systemic conditions
▸ Ehlers-Danlos syndrome
▸ Down Syndrome (KCN 1 in 10)
▸ Osteogenesis Imperfecta
▸ Overexposure to ultraviolet rays from the sun
DIAGNOSIS OF KERATOCONUS DIAGNOSIS OF KERATOCONUS
SYMPTOMS SYMPTOMS
▸ Early ▸ Late
▸ Gradual decrease in best-corrected visual acuities ▸ Increased sensitivity to light and glare ▸ Nearsighted with increasing astigmatism ▸ Highly distorted vision DIAGNOSIS OF KERATOCONUS DIAGNOSIS OF KERATOCONUS
SIGNS SIGNS ON TOPOGRAPHY
▸ Scissor-like reflex on retinoscopy
▸ Keratometer readings
▸ Manual
▸ Auto
▸ Topography, tomography
▸ Pachymetry
DIAGNOSIS OF KERATOCONUS DIAGNOSIS OF KERATOCONUS
SIGNS ON TOPOGRAPHY SIGNS ON TOMOGRAPHY
DIAGNOSIS OF KERATOCONUS DIAGNOSIS OF KERATOCONUS
SIGNS ON PACHYMETRY SIGNS
▸ Slit lamp findings
▸ Early
▸ Vogt’s striae
▸ Fleischer’s ring
▸ Corneal thinning DIAGNOSIS OF KERATOCONUS DIAGNOSIS OF KERATOCONUS
SIGNS CLASSIFICATION AND PROGRESSION
▸ Slit lamp findings ▸ Dutch Crosslinking for Keratoconus (DUCK) scoring to determine condition stability (2019) ▸ Late ▸ Keratometry readings ▸ Munson’s sign ▸ Refractive error ▸ Corneal scarring ▸ Visual acuity ▸ Hydrops (rupture of Descemet’s ▸ Age membrane) 5% ▸ Patient’s assessment of their quality of vision
TREATMENT OF KERATOCONUS TREATMENT OF KERATOCONUS
TREATMENTS
▸ Spectacles 16% (2007 CLEK study)
▸ Contact lenses: avoid apical bearing
▸ Soft lenses
▸ Soft toric
▸ Specialty keratoconic
▸ Small-diameter rigid gas permeable lenses (65% CLEK study)
▸ Hybrid contact lenses
▸ Scleral lenses
KERATOCONUS 101 TREATMENT OF KERATOCONUS KERATOCONUS CONTACT LENS OPTION PROS AND CONS CONTACT LENS REVIEW Soft RGP Scleral Hybrid Soft RGP Scleral Hybrid Good Tear Exchange
Stable Vision Diameter 13.8-14.5mm 9.0-10.5mm ~14.0-18.0mm ~14.5mm
Initial Comfort
>80 >20 >10 1 # Designs Optics
Ease of use Lens cost $-$$$ $-$$ $$-$$$ $$ Lens cost $-$$$ $-$$ $$-$$$ $$ KERATOCONUS 101 KERATOCONUS 101
KERATOCONUS VISION REVIEW: KERATOCONUS LESS LIKELY IN…
▸ Reduced risk associated with smoking, diabetes, age
▸ Increase corneal cross linking
Foreshadowing treatment corneal cross linking!
TREATMENT OF KERATOCONUS TREATMENT OF KERATOCONUS
TREATMENTS TREATMENTS
▸ Surgery ▸ Cross-linking candidacy
▸ Cross-linking: UV + riboflavin (vitamin B2)
▸ Epi-on
▸ Epi-Off (FDA)
▸ Candidacy
TREATMENT OF KERATOCONUS TREATMENT OF KERATOCONUS
TREATMENTS TREATMENTS
▸ Surgery (<15-20% according to NKCF) ▸ Surgery (less common)
▸ Penetrating Keratoplasty (PKP) ▸ Instrastromal Corneal Ring Segments (Intacs)
▸ DALK ▸ Conductive Keratoplasty
▸ Still need correction after TREATMENT OF KERATOCONUS KERATOCONUS RESOURCES
TREATMENTS
▸ New: IVMED-80 in development (Cornea, 2018)
▸ iVeena Delivery Systems
▸ Twice daily copper-based eye drop for the treatment of keratoconus
▸ For “medical crosslinking” of the cornea, works to enhance enzyme in the eye involved in XCL
KERATOCONUS RESOURCES KERATOCONUS RESOURCES
PATIENT RESOURCES PRACTITIONER RESOURCES
▸ National Keratoconus Foundation nkcf.org
▸ Great, simple 1-minute video explanation of the condition
▸ Register
THANK YOU!