Keratoconus: Cause, Symptoms, and Treatment

Keratoconus is a progressive eye condition characterized by the thinning and bulging of the cornea, the clear, dome-shaped front surface of the eye. This structural change alters the cornea’s normal shape, causing it to assume a cone-like form. As a result, vision becomes distorted, and individuals with keratoconus often experience increasing astigmatism and nearsightedness. Understanding the causes, recognizing symptoms, and exploring the diverse treatment options available are crucial aspects of managing and addressing this unique corneal disorder.

Causes of Keratoconus

While the precise etiology of keratoconus remains a subject of ongoing research, several factors are believed to contribute to its development. These include:

  • Genetic Predisposition: There is a significant genetic component associated with keratoconus. Individuals with a family history of the condition are at a higher risk of developing it themselves. Genetic studies have identified certain gene abnormalities linked to keratoconus.
  • Biomechanical Factors: Structural weaknesses in the cornea’s collagen fibers may play a role in the development of keratoconus. These weaknesses can make the cornea more susceptible to thinning and distortion over time.
  • Environmental and Behavioral Factors: Excessive eye rubbing, particularly during adolescence or young adulthood, has been associated with keratoconus. Continuous mechanical stress on the cornea may contribute to its thinning and deformation. Additionally, environmental factors such as UV exposure and allergies may play a role.
  • Hormonal Changes: Some studies suggest a possible link between hormonal changes, especially during puberty, and the onset or progression of keratoconus. Hormones may influence the biomechanical properties of the cornea.
  • Chronic Eye Irritation: Conditions leading to chronic eye irritation, such as dry eyes or allergic conjunctivitis, might contribute to the development or worsening of keratoconus.

While these factors provide insights into potential contributors, the interplay of genetics and environmental factors in the development of keratoconus remains complex and multifaceted.

Symptoms of Keratoconus

Keratoconus typically manifests during adolescence or early adulthood and progresses gradually over time. The symptoms can vary in severity, and individuals may experience a combination of the following:

  • Blurred or Distorted Vision: As the cornea progressively changes shape, vision becomes blurred and distorted. Straight lines may appear wavy or bent.
  • Frequent Changes in Eyeglass Prescriptions: Individuals with keratoconus often require frequent updates to their eyeglass prescriptions as the condition progresses.
  • Increased Astigmatism: Astigmatism, characterized by irregular curvature of the cornea, becomes more pronounced with keratoconus, leading to difficulties in focusing.
  • Sensitivity to Light (Photophobia): Many individuals with keratoconus experience sensitivity to light, making bright lights uncomfortable or irritating.
  • Halos and Glare: The altered corneal shape can cause light entering the eye to scatter, leading to the perception of halos around lights, especially in low-light conditions.
  • Difficulty with Night Vision: Night vision may be compromised, with increased difficulty seeing in low-light environments.
  • Frequent Changes in Contact Lens Prescription: Contact lens wearers may find that their lenses no longer fit properly, requiring adjustments or changes in prescription.
  • Corneal Scarring: In advanced stages of keratoconus, corneal scarring may occur, further compromising vision.

It is important to note that the progression of keratoconus can vary among individuals, with some experiencing a slow progression and others a more rapid deterioration of vision. Regular eye examinations are crucial for early detection and management.

Diagnosis of Keratoconus

Diagnosing keratoconus involves a comprehensive eye examination conducted by an optometrist or ophthalmologist. Key diagnostic tools and procedures include:

  • Corneal Topography: This imaging technique creates a detailed map of the cornea’s surface, highlighting any irregularities or changes in shape associated with keratoconus.
  • Slit-Lamp Examination: The slit-lamp allows for a detailed examination of the cornea’s structure, enabling the healthcare professional to observe any thinning or bulging indicative of keratoconus.
  • Refraction Test: Assessing the refractive error using a phoropter helps determine the degree of nearsightedness and astigmatism, common features of keratoconus.
  • Pachymetry: This measures the thickness of the cornea. Thinning of the cornea is a hallmark characteristic of keratoconus.
  • Visual Acuity Test: This standard eye chart test evaluates how well a person can see at various distances and helps assess the impact of keratoconus on central vision.
  • Keratometry: This measures the curvature of the cornea, providing additional information about its shape.

Early diagnosis is crucial for implementing appropriate management strategies and optimizing treatment outcomes.

Treatment Options for Keratoconus

The management of keratoconus aims to improve visual clarity and halt or slow the progression of the condition. Treatment options vary based on the severity of the condition and individual factors. Some common approaches include:

  • Eyeglasses: In the early stages of keratoconus, individuals may achieve improved vision with prescription eyeglasses. Regular updates to the eyeglass prescription may be necessary as the condition progresses.
  • Contact Lenses: Specially designed contact lenses, such as rigid gas permeable (RGP) lenses or scleral lenses, are often recommended for individuals with keratoconus. These lenses provide a smooth and even optical surface, compensating for the irregularities in the cornea.
  • Hybrid Lenses: Hybrid contact lenses combine a rigid center with a soft outer skirt, offering the comfort of soft lenses and the optical benefits of rigid lenses.
  • Corneal Cross-Linking (CXL): This minimally invasive procedure aims to strengthen the cornea by using ultraviolet (UV) light and riboflavin (vitamin B2). CXL has been shown to slow or halt the progression of keratoconus.
  • Intacs: Intrastromal corneal ring segments, commonly known as Intacs, are small implants placed in the cornea to reshape and provide additional support. This can help improve vision and reduce the need for contact lenses.
  • Customized Soft Lenses: Advancements in soft contact lens technology have led to the development of customized lenses designed to address the unique needs of individuals with keratoconus.
  • Scleral Lenses: Larger than traditional contact lenses, scleral lenses vault over the cornea and rest on the sclera (white part of the eye). These lenses provide greater stability and comfort for individuals with irregular corneal shapes.
  • Corneal Transplant (Penetrating Keratoplasty or PKP): In cases where keratoconus has advanced to a stage where vision cannot be adequately corrected with contact lenses or other interventions, a corneal transplant may be considered. This involves replacing the diseased cornea with a donor cornea. However, corneal transplants are typically reserved for cases where other treatment options are not effective due to the risks and potential complications associated with surgery.
  • Topography-Guided Conductive Keratoplasty (CK): This is a non-invasive procedure that uses radiofrequency energy to reshape the cornea and improve visual acuity. It is primarily considered for individuals with mild to moderate keratoconus.
  • Intrastromal Corneal Cross-Linking (PiXL): PiXL is an alternative cross-linking technique that targets specific areas of the cornea using a lower-intensity UV light. It is being investigated as a potential option for managing keratoconus.
  • Phakic Intraocular Lens (IOL) Implantation: In some cases, especially when the natural lens is clear, a phakic IOL may be implanted to improve vision. This involves placing a lens inside the eye while preserving the natural lens.
  • Collagen Cross-Linking with Topography-Guided Photorefractive Keratectomy (CXL Xtra with TG-PRK): This combination approach involves combining corneal cross-linking with topography-guided photorefractive keratectomy to reshape the cornea and improve visual outcomes.

Living with Keratoconus

Managing keratoconus requires ongoing collaboration between individuals affected by the condition and their eye care professionals. Here are some key considerations for living with keratoconus:

  • Regular Eye Examinations: Continuous monitoring of the condition through regular eye examinations is essential. This allows for timely adjustments to treatment plans and ensures optimal visual outcomes.
  • Compliance with Treatment Plans: Whether using contact lenses, undergoing corneal cross-linking, or exploring other interventions, following the prescribed treatment plan is crucial. Compliance enhances the effectiveness of the chosen approach.
  • Protection from UV Rays: Since UV exposure may contribute to the progression of keratoconus, wearing sunglasses that block harmful UV rays is advisable. This can help protect the eyes and potentially slow down the condition.
  • Avoiding Eye Rubbing: Given the potential association between eye rubbing and keratoconus, individuals with the condition are often advised to avoid excessive rubbing to minimize the risk of further corneal thinning.
  • Adapting to Changes: Keratoconus is a progressive condition, and visual changes may occur over time. Adapting to these changes and communicating openly with eye care professionals are essential for optimizing visual function and quality of life.
  • Exploring Technological Advances: Keeping abreast of technological advancements in the field of keratoconus management can open up new possibilities for improved visual outcomes. This includes staying informed about new contact lens designs, surgical techniques, and treatment modalities.
  • Support Networks: Joining support groups or online communities for individuals with keratoconus can provide a valuable platform for sharing experiences, tips, and coping strategies. Connecting with others who face similar challenges can be empowering.
  • Educating Others: Since keratoconus may not be well-known among the general public, educating friends, family, and colleagues about the condition can foster understanding and support.


Keratoconus presents a unique set of challenges for affected individuals, but advancements in diagnostics and treatment options offer hope for improved outcomes. From contact lenses and corneal cross-linking to emerging technologies and genetic research, the landscape of keratoconus management continues to evolve.

Living with keratoconus requires proactive collaboration between individuals and their eye care professionals. Regular eye examinations, adherence to treatment plans, and staying informed about advancements in the field are essential components of effectively managing the condition.

As research progresses and technology advances, the future holds the promise of more targeted, personalized approaches to keratoconus management. Ultimately, the goal is to enhance the quality of life for individuals affected by this corneal disorder and provide them with the best possible visual outcomes.

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