Progressive thinning and bulging of the cornea leading to distorted vision
What is Keratoconus?
Keratoconus is an eye condition where the cornea (the clear, dome-shaped front surface of the eye) becomes thinner and gradually bulges outward into a cone shape. This abnormal shape distorts vision, causing blurred and distorted images.
The condition usually begins in the teenage years or early twenties and can worsen over time. It typically affects both eyes, although one eye may be more severely affected.
What causes Keratoconus?
The exact cause of keratoconus is not fully understood, but it is believed to involve a combination of genetic, environmental, and cellular factors.
Common contributing factors include:
- Genetic predisposition (family history of keratoconus)
- Chronic eye rubbing (often linked to allergies or irritation)
- Underlying connective tissue disorders (e.g., Marfan syndrome, Ehlers-Danlos syndrome)
- Oxidative stress that weakens corneal tissue
- Certain enzyme imbalances that affect corneal structure
Who is at risk?
- Individuals with a family history of keratoconus
- People with chronic allergic eye disease or habitual eye rubbing
- Those with Down syndrome, Marfan syndrome, or other connective tissue disorders
- Adolescents and young adults (onset is usually before age 30)
- Patients with sleep apnea or asthma (some associations reported)
What are the symptoms of Keratoconus?
Symptoms may vary depending on the stage of the disease and can worsen over time:
- Blurred or distorted vision
- Increased sensitivity to light and glare
- Frequent changes in eyeglass prescriptions
- Difficulty seeing at night
- Halos or ghosting around lights
- Sudden worsening or clouding of vision (if a corneal rupture occurs)
In advanced stages, the cornea can become scarred or swollen, significantly impacting vision.
How is Keratoconus diagnosed?
Diagnosis is typically made through a comprehensive eye examination, which may include:
- Corneal topography – the most accurate way to map the shape of the cornea
- Slit-lamp examination – to observe corneal thinning or protrusion
- Keratometry – measures the curvature of the cornea
- Pachymetry – checks the corneal thickness
- Visual acuity testing – assesses the clarity of vision
How is Keratoconus treated?
Treatment depends on the severity of the condition:
Early to moderate stages:
- Eyeglasses or soft contact lenses to correct mild vision distortion
- Rigid gas-permeable (RGP) contact lenses to provide clearer vision by masking the irregular corneal shape
- Hybrid lenses or scleral lenses for more comfort and better stability
- Corneal collagen cross-linking (CXL) – a procedure that strengthens the corneal tissue to halt progression of the disease
Advanced stages:
- Intacs – small corneal implants that help reshape the cornea
- Corneal transplant (penetrating keratoplasty) – used when other treatments fail or when scarring is severe
- Deep anterior lamellar keratoplasty (DALK) – a type of partial corneal transplant
What is the prognosis for Keratoconus?
- Most people with keratoconus can maintain good vision with the help of corrective lenses or minor procedures
- With early diagnosis and treatment, especially corneal cross-linking, the condition’s progression can often be stopped
- Severe or untreated keratoconus may lead to vision loss, requiring surgical intervention
Can Keratoconus be prevented?
There is no known way to prevent keratoconus completely, but you can reduce the risk of worsening the condition:
- Avoid rubbing your eyes, especially if you have allergies or irritation
- Seek treatment for chronic eye allergies
- Have regular eye exams if you have a family history of keratoconus
- Report any sudden vision changes to an eye care provider promptly
- Early intervention like cross-linking can prevent the need for a corneal transplant later