Keratoconus: Causes, Symptoms, and Treatment

Keratoconus is an eye condition where the structure of the cornea is gradually altered, resulting in a major distortion of vision. This progressive disease is generally diagnosed in adolescence or early adulthood and progressively worsens over time. 

Further, the cornea becomes thinner during the later stages of the disease. It bulges into the shape of a cone, making it difficult for the eye to focus properly, resulting in blurred or distorted images. If not addressed promptly, the implications may greatly affect visual performance and lifestyle. 

Therefore, understanding the causes, symptoms, and treatment options available for keratoconus is paramount for early intervention and better management of this vision-threatening eye condition.

What is Keratoconus?

Keratoconus is a progressive, non-inflammatory eye condition that affects the shape and structure of the cornea. The cornea of a normal, healthy eye is round and dome-shaped. In keratoconus, it flattens and becomes conical through gradual thinning and bulging. This deformity distorts vision and greatly influences a person’s day-to-day functioning.

The word keratoconus derives from Greek: “kerato” refers to the cornea, and “conus” means cone. A structurally weakened cornea is referred to as keratoconus eye disease.

Can Keratoconus Affect Your Vision?

Keratoconus alters the corneal surface and causes irregular astigmatism and light scattering. As the disease advances, vision becomes increasingly blurred and distorted. Night vision is often the first to be affected.

Patients often see double or ghost images, especially when looking at bright lights. In advanced stages, vision may not be corrected through glasses, but specialised contact lenses or surgery will be indicated.

Common Keratoconus Causes

Now, although the exact keratoconus causes have not been determined, they have been linked to several contributing factors:

1. Genetics. A family history of keratoconus significantly increases risk.
2. Rubbing the Eyes: Vigorous or chronic rubbing may sometimes aggravate or initiate the condition.
3. Associated Conditions: Associated with some systemic disorders, like Down syndrome, Ehlers-Danlos syndrome, and sleep apnoea, which put an individual at risk.
4. Environmental Factors: Exposure to ultraviolet rays, allergens, or eye irritants may also contribute to cornea thinning.

Although these factors alone may not be sufficient to develop keratoconus, their combination increases its chances.

Signs and Symptoms of Keratoconus

Keratoconus signs and symptoms can be rather mild. They begin during adolescence or early adulthood and worsen gradually over time. Keratoconus suggests most commonly:

• Blurred or distorted vision
• Increased sensitivity to light 
• Increased frequency of changes in eyeglass prescription 
• Haloes and glare at night 
• Eye strain or headaches 
• Difficulty driving at night, in particular 

In most cases, symptoms appear in both eyes, but not necessarily simultaneously or to the same extent. 

Diagnosis of Keratoconus

Examinations by an ophthalmologist and further diagnostic workup are required to confirm keratoconus. The evaluation process includes:

1. Corneal Topography: The most sensitive test for detailed topographic mapping of corneal curvature.
2. Pachymetry: Checks the corneal thickness for thinning detection. 
3. Slit-lamp Examination: Allows the doctor to see structural changes. 
4. Keratometry: Measurement of the cornea’s shape and power. 

These tools will also confirm the presence of keratoconus and help define its severity and progression.

Treatment for Keratoconus

Keratoconus treatment varies according to the stage and severity of the disease; its purpose is to curb its progression, improve vision, and maintain the cornea’s stability.

Non-Surgical Options:

• Spectacles: Useful in the first few stages but usually ineffective as the disease progresses.
• Rigid Gas Permeable (RGP) Lenses: Provide better optical correction by making an even refractive surface.
• Hybrid and Scleral Lenses: Used in advanced cases where ordinary lenses cannot fit properly.

Surgical Options:

• Corneal Cross-linking (CXL): CXL is a treatment method for keratoconus in which riboflavin drops are applied and activated through ultraviolet light to strengthen corneal fibres and stop the progression of keratoconus.
• Intracorneal Ring Segments (ICRS): small arcs inserted in the cornea to flatten the cornea and generally improve vision.
• Keratoplasty (corneal transplant) is the option of choice when it comes to scarring or extreme thinning. It replaces damaged corneal tissue with a donor graft. It is the last step in keratoconus surgery in case other treatments fail.

Risk Factors of Keratoconus

Several risk factors have an increased chance of developing keratoconus:

1. Genetic: First-degree relatives have the highest incidence.
2. Chronic Eye Rubbing: Often related to allergies or behavioural activity.
3. Systemic Conditions: Associated with connective tissue disorders.
4. Ethnicity: Some populations, such as those in South Asia and the Middle East, show higher prevalence.

These factors can help in the early detection and timely management of keratoconus..

Complications of Keratoconus

If not treated, keratoconus can lead to serious complications:

• Severe Vision Impairment: That cannot be corrected with normal lenses.
• Cornea Scarring: Typically occurs in the more advanced forms.
• Hydrops: Sudden breakage in the inner part of the cornea, causing swelling, pain and rapid loss of vision.
• Post-keratoplasty Complications: Risk of other eye diseases, such as glaucoma and cataracts, is higher.
• Stress to the Retina: Though rare, very high myopia associated with keratoconus could have secondary effects on the retina.

Prompt diagnosis and management are important to limit vision loss and minimise dependency on invasive surgery. 

Conclusion

Keratoconus denotes a progressive keratoconus disease affecting the eye and significantly impacting vision since the cornea thins and takes an irregular shape. Signs of early development can go unnoticed but may lead to serious impairment in visual capability with progression. Timely diagnosis, regular monitoring, and consideration of a non-surgical or surgical keratoconus treatment can preserve vision and enhance one’s quality of life.

What keratoconus is, the early signs and symptoms of keratoconus, and what can be done, whether through contact lenses or keratoconus surgery, have given patients and healthcare providers the tools they need to manage this complex disease. Neglected keratoconus may cause further ocular problems, including but not limited to astigmatism, double vision, and secondary complications such as glaucoma or retinal damage. Awareness, education, and early medical care remain pivotal in the control of this progressive keratoconus disease.