Edmonds, Husz

1
Edmonds, Husz Pemberton Eye Center

• What is Keratoconus??

2
The Cascade Hypothesis of KCCristina Kenney
Ph.D.

• Keratoconus corneas have increased oxidative
  damage compared to normal corneas.
• In the stroma, collagen fibers are degraded
  quicker than they are synthesized due to exposure
  to UV light, mechanical trauma (eye rubbing,
  contact lenses, surgery) and atopic disease.
• With the accumulative traumas, there is a
  resultant deposition of cytotoxic by-products
  causing an alteration of corneal proteins that
  can.
• disrupt Bowmans layer
• thin the stroma
• result in corneal scarring

3
Cellular Insult in Keratoconus

• Effect
• Epithelial compromise (keratocyte destruction)
• Disruption of Bowmans layer
• Stromal thinning
• Endothelial changes

• Cause
• Eye rubbing
• Poorly fit Contact lens
• Low Dk/t CL
• Corneal Surgery
• Allergy
• UV

4
1 Subepithelial Fibrosis
Normal Cornea
Keratoconus
5
2 Disruptions in Bowmans
Intact Bowmans
Rupture in Bowmans
6
Disruptions in Bowmans

• Decreased Levels of
• Fibronectin
• Laminin
• Entactin
• Type IV Collagen

7
3 Stromal Fibrosis
Decreased Levels of Fibronectin Laminin
Entactin Type IV Collagen Increased Levels of
Tenascin-C Type III Collagen Fibrillin-1
8
Anterior Stromal Apoptosis

• The programmed cell
• death that occurs in
• normal tissue development, disease and wound
  healing.
• In Keratoconus
• chronic epithelial trauma
• secondary to
• Decreased proteinase inhibitors
• Increased levels of free radicals
• Genetics
• Chronic irritation
• results in increased stromal cell death

Apoptosis of Anterior Stroma
9
4 Endothelial cell damage ( CL INDUCED ?
10
Things We Can Do To Limit Oxidative Stress

• Suggest UV protection in CLs and glasses.
• Pharmacological intervention
• Non-steroidal anti-inflammatory
• PF artificial tears
• Allergy medications
• Minimize mechanical and physiological epi trauma
• Proper fitting RGP lenses
• Soft lenses / Piggyback lenses
• High Dk/t lens
• Intacs surgery dissector vs intralase

11
Associated Conditions
12
Associated ConditionsMulti-system

• Alagille Syndrome
• Albers-Schonberg Syndrome
• Aperts Syndrome
• Autographism
• Bardet-Biedl Syndrome
• Crouzons Syndrome
• Downs Syndrome
• Ehlers-Danlos Syndrome
• Goltz-Gorlin Syndrome
• Hyperornithemia
• Icthyosis
• Kurz Syndrome
• Laurence-Moon-Beidl Syndrome
• Marfan Syndrome

• Mulvihil-Smith Syndrome
• Nail-patella Syndrome
• Neurocutaneous angiomatosis
• Neurofibromatosis
• Noonans Syndrome
• Osteogenesis imperfecta
• Oculodentodigital Syndrome
• Pseudoxanthoma elasticum
• Reigers Syndrome
• Rothmunds Syndrome
• Tourettes Syndrome
• Turners Syndrome
• Xeroderma pigmentosa

13
Associated ConditionsOcular

• Anetoderma and bilateral subcapsular cataracts
• Microcornea
• Persistent pupillary membrane
• Posterior lenticonus
• Retinitis pigmetosa
• Retinopathy of prematurity
• Retrolental fibroplasia
• Vernal conjunctivitis

• Aniridia
• Ankyloblepharon
• Bilateral macular coloboma
• Blue Sclerae
• Congenital cataracts
• Ectodermal and mesodermal anomalies
• Floppy eyelid syndrome
• Gyrate atrophy
• Iridoschisis
• Lebers congenital amaurosis

14
Associated ConditionsCorneal

• Atopic keratoconjuntivitis
• Axenfelds anomaly
• Chandlers syndrome
• Corneal amyoidosis
• Deep filiform corneal dystrophy
• Essential iris atrophy
• Fleck corneal dystrophy

• Fuchs corneal dystrophy
• Iridocorneal dysgenesis
• Lattice dystrophy
• Pellucid marginal degeneration
• Posterior polymorphous dystrophy
• Terriens marginal degeneration

15
Associated ConditionsOther

• Congenital hip dysplasia
• False chordae tendinae of left ventricle
• Joint hypermobility
• Mitral valve prolapse
• Measles retinopathy
• Ocular hypertension
• Thalesselis syndrome