Cornea Anatomy and Clinical Management

Corneal Epithelium Thickness

• Approximately 50 micrometers thick

Corneal Stroma

• Primary component, over 90% of corneal thickness
• Composed of collagen fibers arranged in a highly organized, parallel fashion

Descemet's Membrane Purpose

• Acts as a barrier against infection and inflammation
• Plays a role in corneal wound healing

Corneal Refractive Index

• Approximately 1.376

Corneal Light Transmission

• Maximal transmission at 555 nm (green light)

Corneal Radius Of Curvature

• Average radius of curvature: 7.8 mm

Punctate Epitheliopathy Location

• Typically occurs on the corneal epithelium, often caused by dry eye, viral infections, or certain medications

Pterygium vs. Pinguecula

• Pterygium: A triangular, fleshy growth of conjunctiva that extends onto the cornea
• Pinguecula: A yellowish, raised nodule on the conjunctiva, usually on the nasal side of the cornea, does not extend onto the cornea

Keratoconus Characteristics

• NOT a characteristic of Keratoconus: Myopia
• Commonly seen in patients with keratoconus:
  • Astigmatism
  • Increased corneal curvature
  • Thinning of the cornea
  • Conical shaped protrusion of the cornea

Keratoconus Onset

• Typically starts in adolescence (around 10-20 years old), but can develop later in life

Degeneration of Collagen Fibers in Conjunctival Stroma

• Pinguecula

Keratoconus Associated Conditions

• Down syndrome
• Atopic keratoconjunctivitis
• Ehlers-Danlos Syndrome

Embedded Foreign Body

• Primary consideration: to ensure that the foreign body is not embedded in the cornea

Inferior Corneal Thinning Shape

• The shape of the area of inferior corneal thinning is crescentic

Superficial Foreign Body Removal

• Typically removed using a moistened cotton swab or a sterile saline solution
• May use a needle or forceps in some cases

Keratoconus Treatment

• Approximately 15-25% of Keratoconus cases require Epikeratoplasty or Penetrating keratoplasty

Corneal Abrasion Risk Factor

• Dry eye

Greyish-White Polygonal Stromal Opacities

• Matsen's dystrophy

Corneal Collagen Crosslinking UV Wavelength

• 308 nm

Topical Antibiotic Ointment Purpose

• Prevents infection

Age-Related Corneal Opacity

• Arcus senilis

Corneal Collagen Crosslinking Healing Time

• Typically takes 3-6 months

Seidel's Test

• Detects a leak in the cornea associated with foreign bodies

Focal Collagen Accumulations on Descemet's Membrane

• Posterior polymorphous dystrophy

High Increasing Regular Astigmatism Treatment

• Corneal refractive surgery, such as LASIK or PRK

Corneal Abrasion Defect Assessment

• Assess the depth and extent of the corneal abrasion
• Evaluate the risk of infection
• Determine the need for treatment

Keratoglobus Onset

• Typically onset in childhood

Pellucid Marginal Degeneration Age Range

• Typically onset in the 2nd to 4th decade of life

Bilateral Narrow Crescentic Lines with Chalklike Flecks

• Salzmann's nodular degeneration

Test your knowledge of cornea anatomy, signs and symptoms of corneal problems, and clinical management guidelines. Covers corneal ectasias, degenerations, dystrophies, and surgical procedures. Useful for optometry students and professionals.