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What is Keratoconus: What You Need to Know About This Eye Condition

Medically reviewed by Victor Paulino, MD, DPBO · Ophthalmology · Makati Medical Center

Written by Shienna Santelices · Updated Feb 18, 2022

What is Keratoconus: What You Need to Know About This Eye Condition

What is keratoconus? Keratoconus is a non-inflammatory eye disorder in which the cornea gradually thins, bulging outward in the shape of a cone. It usually affects only one eye, but it can eventually develop in both eyes. 

What is Keratoconus?

The severity of keratoconus differs from patient to patient, depending on several factors. Patients may experience blurry vision and light-sensitivity that can be an early symptom of this condition that can lead to vision impairment if not treated during the early stage.

Symptoms of keratoconus may develop during late teens up to 30 years of age. It is considered a rare eye condition as it affects 1 out of 2,000 individuals worldwide. 

What are its Causes? 

The primary cause of keratoconus is undefined. However, professionals believe that this disease is already present at birth and which develops later in puberty to adulthood.

Based on research, the common finding among keratoconus patients is the loss of collagen in the cornea. Collagen is the second layer of the cornea that is made up of water and protein. It is responsible for the eye keeping its shape. The loss of collagen is due to an imbalance in production and destruction of the corneal tissue by the corneal cells.

Risk Factors

The following are the factors that may increase the risk of the development of keratoconus:


Research shows that keratoconus is a genetic disease. One in 10 patients of this disease has a relative who suffers from the same condition. However, researchers believe that the development of keratoconus only occurs when triggered by environmental factors.


Most teenagers are diagnosed with an advanced stage of keratoconus. In this situation in which the disease progresses, they are more likely to get treated by some surgical procedures.

Chronic Eye Inflammation

The development of keratoconus may be triggered by experiencing constant inflammation due to environmental factors. These factors include wearing contact lenses and having health conditions that lead to hypersensitivity reactions like fever, allergy, and eczema.

Eye Rubbing

Aggressive eye rubbing may cause trauma in the eye that may lead to the thinning of the cornea. It is an unclear cause of keratoconus, but it may be a factor in aggravating the condition. 


Keratoconus is barely visible. The following tests are needed to perform by an eye care professional to check signs of the condition:

Corneal Topography

The most accurate test among all the other examinations is an imaging test that captures the projections from the light rings placed on the cornea. The recording will help in determining the shape and integrity of the cornea. Corneal topography is also useful in monitoring the progression of the keratoconus and its severity.

Slit-Lamp Examination

For this test, a vertical beam light is used directly on the surface of the cornea. Using a microscope, the doctor will examine the shape or potential problems of the eye.


It is primarily used for screening patients with glaucoma. It is a test that measures the thickness of the cornea.


This test is for measuring astigmatism. However, the reflection coming from the circle light focusing on the eye can help determine the shape of the cornea. 


Keratoconus can be addressed with the following options:


Patients diagnosed with an early stage of keratoconus can use appropriate eyeglasses or soft contact lenses to improve blurry or distorted vision. 

Contact Lenses

If the disease has progressed into an advanced stage, eyeglasses and soft contact lenses are not helpful anymore. Using fit and hard contact lenses (gas permeable) will help in reshaping the cornea and also provide excellent vision. 


It is a known treatment procedure that successfully treats patients with keratoconus. This process involves ultraviolet A light and a type B vitamin riboflavin used through eye drops. The riboflavin acts as the photosensitizer that helps the corneal tissues to absorb the ultraviolet light.

Corneal Ring

If the keratoconus is in its advanced stage, the corneal ring is one of the appropriate treatments out there. The procedure includes implantation of C-shaped intra-stromal corneal segments in the substance of the cornea that will help in improving the vision. After the implantation, contact lenses will have a better fit. 

Corneal Transplant

It is a surgical procedure that replaces the cornea. However, the vision after the surgery is arbitrary. Thus, it will require the use of eyeglasses or contact lenses for better sight. Blurry vision will remain for about three to six months after the procedure, and taking medications is a must to prevent transplant rejection.

Key Takeaways

Keratoconus is an uncommon but not rare eye disorder that affects the cornea. It causes the said part of the eye to thin and bulge into a cone shape.

Most people who develop this disease are mostly teenagers and adults who will experience blurry and distorted vision.

This disease will lead to vision impairment and loss if not treated earlier. Some factors may increase the risk of developing keratoconus, but there are no ways to prevent it. Still, some treatments can help in easing the symptoms of this disorder.

Learn more about Eye Diseases here.


Hello Health Group does not provide medical advice, diagnosis or treatment.

Medically reviewed by

Victor Paulino, MD, DPBO

Ophthalmology · Makati Medical Center

Written by Shienna Santelices · Updated Feb 18, 2022

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