Corneal Cross-Linking Delays Due to COVID-19 Cause Worsening Keratoconus

Over the past 14 or so months, COVID-19 has dominated the headlines. It has reshaped the way that we work, attend school, build relationships with others, and receive medical treatment. In many cases, doctors have pushed back “non-urgent” medical procedures to protect people from the possibility of getting COVID-19. Unfortunately, this has caused some additional medical issues in and of itself. According to Healio, patients with keratoconus who delayed corneal cross-linking treatment now have increased disease progression and vision loss.

Corneal Cross-Linking

According to All About Vision, corneal cross-linking is a procedure used to treat keratoconus and other conditions which cause corneal weakening. All About Vision explains:

The corneal cross-linking procedure strengthens and stabilizes the cornea by creating new links between collagen fibers within the cornea. The two-step procedure applies specialty formulated riboflavin (vitamin B) eye drops to the surface of the eye immediately followed by a controlled exposure of the eye to ultraviolet light.

Towards the onset of the pandemic, the Royal College of Ophthalmologists (UK) shared guidelines for ophthalmologic treatment. In it, they listed patients with keratoconus as low-risk.

However, new research suggests that this might have been a mistake. Researchers from the Royal Liverpool University Hospital evaluated 34 patients with keratoconus who delayed corneal cross-linking for 3+ months. During this study, the researchers determined that:

  • The keratoconus worsened in a majority of patients. In fact, about 70% experienced disease progression.
  • 17% of patients saw increased corneal thinning.
  • Patients with keratoconus who delayed their procedures saw a loss of visual acuity. Unfortunately, a loss of visual acuity that cannot be fixed with glasses or contacts can only be fixed with an invasive surgical procedure: a corneal transplant.

Now, researchers believe that keratoconus needs to be treated within 6 weeks (1.5 months) following diagnosis to prevent disease progression and protect both ocular health and visual acuity.


Doctors are unsure what exactly causes keratoconus, a corneal disorder characterized by progressive corneal thinning. As the cornea thins, the center of the eye bulges, causing a conical (cone-shaped) bulge. However, a variety of potential factors for developing keratoconus include a family history, genetics, frequent or intense eye rubbing, having Down syndrome or Marfan syndrome, intense sunlight exposure, or allergies. Patients who are Black or Latinx are more likely to develop keratoconus than white individuals. Symptom onset usually occurs in teenage years, though it can also occur in childhood or adulthood. Symptoms include:

  • Increased light sensitivity
  • Blurry vision
  • Sudden clouded or worsening vision
  • Light streaks
  • Halos around light sources
  • Nearsightedness
  • Difficulty driving

Learn more about keratoconus.

Jessica Lynn

Jessica Lynn

Jessica Lynn has an educational background in writing and marketing. She firmly believes in the power of writing in amplifying voices, and looks forward to doing so for the rare disease community.

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