Cornea
Overview
The cornea is the transparent, dome-shaped surface that covers the front of the eye. It covers the iris, pupil, and anterior chamber and serves several key functions. Maintaining corneal health is vital for clear vision, and various conditions or injuries can affect its function and transparency.
- Refractive Power: The cornea provides most of the eye’s optical power by bending (refracting) light that enters the eye. This helps to focus light onto the retina for clear vision.
- Protection: It acts as a barrier to dust, germs, and other particles, protecting the inner structures of the eye.
- Transparency: Its clear nature allows light to pass through unobstructed, which is essential for good vision.
- Shape: The cornea’s curvature and shape are crucial for proper focus. Any irregularities can lead to vision problems like astigmatism.
Different layers of Cornea
- Epithelium: The outermost layer, which helps protect the cornea and aids in healing.
- Bowman’s Layer: A tough layer that provides structural support.
- Stroma: The thick middle layer, which contains collagen fibers and provides the cornea’s strength and elasticity.
- Descemet’s Membrane: A thin but strong layer that supports the inner layers of the cornea.
- Endothelium: The innermost layer, which helps maintain the cornea’s clarity by regulating fluid levels.
Different types of Cornea disorders
Keratitis
Infections (bacterial, viral, fungal, parasitic), injury, prolonged contact lens wear, contaminated contact lenses, autoimmune diseases
Corneal Ulcer
Infections, severe dry eye, eyelid disorders, trauma, extended contact lens wear
Keratoconus
Exact cause unknown, possibly genetic factors and eye rubbing
Fuchs’ Endothelial Dystrophy
Genetic factors, age-related changes
Corneal Abrasion
Trauma, foreign bodies, contact lens complications
Corneal Dystrophies
Genetic factors
Corneal Edema
Endothelial dysfunction (e.g., Fuchs’ dystrophy), trauma, post-surgical changes, inflammation
Pterygium
Prolonged exposure to UV light, wind, dust, dry conditions
Symptoms
- Redness, pain, excessive tearing, blurred vision, light sensitivity, discharge, sensation of something in the eye
- Severe pain, redness, blurred vision, discharge, light sensitivity, white or gray spot on the cornea
- Progressive thinning and bulging of the cornea into a cone shape, distorted vision, glare, light sensitivity
- Gradual loss of endothelial cells, corneal swelling (edema), blurred vision, glare, halos around lights, pain
- Pain, redness, tearing, light sensitivity, sensation of something in the eye
- Vision impairment, glare, discomfort; types include lattice dystrophy, granular dystrophy, macular dystrophy
- Blurred vision, halos around lights, sensation of pressure or pain
- Growth of fleshy tissue on the conjunctiva extending onto the cornea, redness, irritation, blurred vision if it encroaches on the visual axis
Treatments @ ABO
- Antimicrobial medications (antibiotics, antivirals, antifungals), anti-inflammatory eye drops, proper contact lens hygiene, severe cases may require corneal transplantation
- Antimicrobial therapy, protective eyewear, severe cases may require corneal transplantation
- Glasses or soft contact lenses (mild cases), rigid gas-permeable contact lenses (advanced cases), corneal cross-linking, severe cases may require corneal transplantation
- Hypertonic saline eye drops, soft contact lenses, advanced cases may require endothelial keratoplasty or full-thickness corneal transplantation
- Pain, redness, tearing, light sensitivity, sensation of something Lubricating eye drops, antibiotic eye drops to prevent infection, severe cases may require bandage contact lens or patching
- Lubricating eye drops, contact lenses to improve vision, severe cases may require corneal transplantation
- Hypertonic saline eye drops, reducing intraocular pressure, severe cases may require corneal transplantation
- Lubricating eye drops, anti-inflammatory medications, surgical removal if it affects vision or causes significant discomfort