Keratoconus: what it is and how it progresses

Keratoconus is an eye condition in which the cornea, the clear dome at the front of the eye, thins and bulges outward into a cone shape. The changed shape bends light unevenly, so vision becomes blurry and distorted, and glasses stop correcting it fully. The cause is not known for certain; keratoconus tends to run in families, it is linked to eye allergies and eye rubbing, and in most people the changes worsen gradually over a period of years.

Keratoconus at a glance

• Part of the eye affected: the cornea, the clear front window that focuses light into the eye.
• What changes: the cornea thins and steepens into a cone, which produces irregular astigmatism.
• When it usually starts: the late teens to early twenties, with symptoms that worsen slowly over roughly 10 to 20 years.
• Eyes affected: usually both, often to different degrees.
• Known associations: a family history (about 1 in 10 people with keratoconus have a parent who has it), eye allergies, eye rubbing, and certain connective tissue disorders.
• How it is found: an eye exam that includes corneal mapping (topography) and a measurement of corneal thickness.
• Treatments offered at our Westerville office: glasses and soft contact lenses in the early stage, specialty contact lenses, corneal crosslinking, and corneal transplant.

What keratoconus does to the cornea

The cornea focuses light into the eye. A healthy cornea is evenly curved, like the surface of a ball, so light passing through it lands in focus on the retina. In keratoconus the cornea loses some of its strength, grows thinner, and the thinned area steepens and bulges forward. The MedlinePlus Medical Encyclopedia describes the shape slowly changing from round to cone.

A cone shaped cornea bends light unevenly. The result is irregular astigmatism, a focusing error that eyeglasses cannot correct the way they correct ordinary nearsightedness or astigmatism. That is why a person with keratoconus often reports that new glasses never seem quite right, and why rigid or specialty contact lenses, which create a smooth new front surface for the eye, do a better job of restoring clear vision.

Keratoconus is not an infection and it is not caused by anything a person did at work or at school. It is a structural change in the corneal tissue itself, and the sections below cover what is known about why it happens and how it moves over time.

What causes keratoconus

The cause of keratoconus is not known for certain. The American Academy of Ophthalmology states that doctors do not know for sure why people develop it, and that in some cases it appears to be genetic. MedlinePlus adds that the tendency is likely present from birth and may be due to a defect in collagen, the tissue that gives the cornea its shape and strength.

Several factors are associated with keratoconus, which means they are found more often in people who have it, even though none of them is a proven cause on its own:

• Family history. About 1 in 10 people with keratoconus have a parent who has it too (American Academy of Ophthalmology).
• Eye allergies, and the itching that comes with them.
• Excessive eye rubbing. MedlinePlus states that allergy and eye rubbing may speed up the damage.
• Connective tissue disorders such as Marfan syndrome and Ehlers-Danlos syndrome.
• Down syndrome. MedlinePlus notes a link between keratoconus and Down syndrome.

Because allergies and rubbing are the two associations a person can act on, controlling itchy eyes is part of keratoconus care at our office. The section on eye rubbing below explains why.

What keratoconus feels like

Keratoconus symptoms begin mildly and change over time, and they can be different in each eye. If any of these describe your vision, an eye exam with corneal mapping is how the cause is sorted out; the symptoms alone do not mean keratoconus is present.

Early symptoms

• Mild blurring of vision, often the first sign, and blurring that glasses do not fully correct.
• Slightly distorted vision, where straight lines look bent or wavy.
• More sensitivity to light and glare.
• Halos around lights and more trouble seeing at night.
• Eye redness or swelling.

Later symptoms

• Blurring and distortion that are more pronounced.
• Nearsightedness or astigmatism that keeps increasing, so your eyeglass prescription changes often.
• Contact lenses that no longer fit comfortably or stay in place.

Most people with keratoconus have a history of nearsightedness, and the nearsightedness tends to get worse as the cornea steepens. A prescription that keeps changing from one visit to the next is one of the clearest reasons to have the cornea mapped.

How keratoconus progresses

Keratoconus is a progressive condition in most people. The American Academy of Ophthalmology states that it often starts in the late teens to early twenties and that the vision symptoms slowly worsen over a period of about 10 to 20 years. MedlinePlus notes that it is often discovered during the teenage years, although it may also develop in older people.

Progression is usually gradual, but not always. For some people keratoconus worsens quickly, and the cornea can swell suddenly and begin to scar. Scar tissue makes the cornea less smooth and less clear, which adds to the blur and distortion. Sudden swelling is one of the reasons the same day symptoms list below matters for anyone who has been diagnosed.

Keratoconus usually affects both eyes, but not equally. One eye may be much further along than the other, and symptoms can change at different rates in each. That asymmetry is why the two eyes are mapped and tracked separately at every visit.

The rate of change is what determines treatment. The American Academy of Ophthalmology’s Corneal Ectasia Preferred Practice Pattern recommends corneal crosslinking for progressive keratoconus because it stabilizes the cornea and reduces the risk of further progression. Tracking the cornea over time is therefore the core of keratoconus care, and the next section explains how that tracking is done.

How keratoconus is diagnosed

Keratoconus is diagnosed during an eye exam. The American Academy of Ophthalmology notes that it can be found during a routine eye exam, where the ophthalmologist examines the cornea and may measure its curvature and map its surface. The Corneal Ectasia Preferred Practice Pattern states that patients with unstable refractions, meaning a prescription that will not settle, should be evaluated for evidence of corneal ectasia, the broader term for a thinning and bulging cornea.

Three tests do most of the work:

• Corneal topography, a map of the curvature of the cornea’s surface. MedlinePlus calls it the most accurate test for keratoconus. The map shows the steepening pattern that marks the condition, and repeated maps over time show whether it is changing.
• Corneal tomography, a related scan that measures the front and back surfaces of the cornea and its thickness across its whole width.
• Pachymetry, a measurement of corneal thickness, which is reduced in keratoconus.

A slit lamp examination, the microscope examination used at every eye exam, can show the signs of keratoconus in its later stages. At our office these tests are part of a keratoconus evaluation, and the same maps are repeated at follow up visits so that any change can be measured rather than guessed.

Keratoconus treatment at Comprehensive EyeCare of Central Ohio

Keratoconus treatment depends on the stage of the condition and on whether it is still progressing. Our practice offers each of the treatments below at the Westerville office, under the direction of our Director of Corneal Services, with ophthalmologists and optometrists in the same building so that corneal care, lens fitting, and routine eye care can happen in one place.

Glasses and soft contact lenses

Glasses and soft contact lenses correct vision in the early stage. The American Academy of Ophthalmology states that when symptoms are mild, vision can be corrected with eyeglasses or soft contact lenses. They correct the focusing error for a time; they do not change the cornea.

Specialty contact lenses

Specialty contact lenses restore clearer vision once glasses fall short. Rigid gas permeable, hybrid, and scleral lenses hold their own shape and create a smooth, regular front surface over the irregular cornea. MedlinePlus states that contact lenses are the main treatment for most patients with keratoconus and that in most cases vision can be corrected with rigid gas permeable lenses, while noting that lenses provide good vision but do not treat or stop the condition. The Corneal Ectasia Preferred Practice Pattern states that specialty contact lenses, including hybrid and scleral lenses, should be tried for visual rehabilitation before a transplant and may delay and even eliminate the need for one. Specialty lens fitting is offered at our office.

Corneal crosslinking

Corneal crosslinking is intended to strengthen the cornea and slow or halt progression. The procedure uses riboflavin eye drops and ultraviolet light to create new bonds within the corneal tissue; the American Academy of Ophthalmology describes it as a way to stiffen the cornea and keep it from bulging further. The Corneal Ectasia Preferred Practice Pattern states that crosslinking reduces the risk of progressive ectasia in patients with keratoconus and recommends it as the treatment for progressive keratoconus. Our practice performs corneal crosslinking with the KXL System. Crosslinking does not replace glasses or contact lenses; most people still need them for clear vision afterward, and it does not undo scarring that has already formed.

Corneal transplant

A corneal transplant replaces all or part of the cornea with donor tissue. The American Academy of Ophthalmology states that an ophthalmologist may suggest a transplant when symptoms are severe. The Corneal Ectasia Preferred Practice Pattern names two approaches, a full thickness transplant (penetrating keratoplasty) and a partial thickness transplant (deep anterior lamellar keratoplasty), and states that the partial thickness approach carries no risk of rejection of the inner corneal layer. MedlinePlus notes that results are very often good, that the recovery period can be long, and that many people still need contact lenses after surgery. Corneal transplant surgery for keratoconus is performed by our Director of Corneal Services.

Which of these fits you depends on your corneal maps, your vision in glasses and lenses, and whether the maps are changing. A keratoconus evaluation at our office is where that decision is made.

Call us the same day if you notice any of these

Some symptoms need care the same day. Call 614-890-5692 or go to an emergency room if you have:

• A sudden drop in vision in one eye or both, even if it lasts only a short time. MedlinePlus states that sudden vision loss is always an emergency, even when vision is not completely lost.
• A sudden clouding of vision with pain or redness in one eye, which can mean the cornea has swollen suddenly, as can happen in keratoconus.
• A red, painful eye with light sensitivity, watering, or discharge, especially if you wear contact lenses. The American Academy of Ophthalmology states that these can be symptoms of a corneal infection and that treatment must start right away. Remove the lens and call.
• A chemical splash in the eye. Flush the eye with plenty of clean water right away and seek emergency care.
• A cut to the eye or an object stuck in the eye. Do not rinse it and do not try to remove the object; cover the eye gently and get emergency care.

During office hours, call 614-890-5692 and ask for the first available evaluation. If you have a medical emergency during evening or weekend hours, call the same number and a physician on call will contact you.

Eye rubbing and allergies: what you can do

Eye rubbing matters more in keratoconus than in almost any other eye condition. The American Academy of Ophthalmology advises people with keratoconus to avoid rubbing their eyes, because rubbing can damage thin corneal tissue and make symptoms worse, and to talk with their ophthalmologist about medicines to control allergies if itching is what drives the rubbing. MedlinePlus states that there is no known way to prevent keratoconus, and that most health care providers believe people should control allergies and avoid rubbing their eyes.

At our office, allergy control is part of the keratoconus visit. Itchy eyes have treatable causes, and treating them removes the urge to rub. If you catch yourself rubbing, tell us; it is one of the few parts of this condition that you and we can act on together.

World Keratoconus Day is November 10

World Keratoconus Day is observed on November 10 each year. The day, sponsored by the National Keratoconus Foundation, is set aside to bring attention to a condition that most people have never heard of until it affects them or someone in their family, and to recognize the people who live with it. For a condition that often begins in the teenage years and is usually caught only when glasses stop working well, attention matters: the earlier keratoconus is found, the more options there are for stabilizing the cornea and keeping vision correctable. If you or someone close to you has keratoconus, or you have been told your prescription keeps changing for no clear reason, November is a good month to put an eye exam with corneal mapping on the calendar. Our Westerville office sees patients with keratoconus year round; call 614-890-5692 to schedule.

Frequently asked questions about keratoconus

Is keratoconus hereditary?

Keratoconus runs in some families. The American Academy of Ophthalmology states that about 1 in 10 people with keratoconus have a parent who has it, and that in some cases the condition appears to be genetic. Most people with keratoconus have no affected relative, so a family history raises the chance of the condition without settling it. If a parent or sibling has keratoconus, mention it at your eye exam so the cornea can be mapped.

Can keratoconus be cured?

No treatment returns the cornea to its original shape. Glasses and contact lenses correct the vision without changing the cornea; MedlinePlus states that lenses provide good vision but do not treat or stop the condition. Corneal crosslinking is intended to stabilize the cornea and reduce the risk of further progression, and a corneal transplant replaces the damaged tissue. Keratoconus is managed over a lifetime, and with regular corneal mapping most people keep useful, correctable vision.

Does keratoconus stop progressing?

Keratoconus usually progresses slowly over many years. The American Academy of Ophthalmology states that symptoms worsen over about 10 to 20 years and that it usually takes years to go from the early to the late stage, while for some people it worsens quickly. Whether keratoconus is still progressing is measured, not assumed: repeated corneal maps show whether the cornea is steepening, and that measurement is what guides the decision about crosslinking.

What is the difference between keratoconus and astigmatism?

Ordinary astigmatism is a common focusing error in which the cornea is shaped more like a football than a ball, and it is fully corrected with glasses. Keratoconus produces irregular astigmatism from a thinned, cone shaped cornea, and glasses cannot fully correct it. MedlinePlus describes the earliest symptom of keratoconus as a slight blurring that cannot be corrected with glasses, and the Corneal Ectasia Preferred Practice Pattern directs that anyone whose prescription keeps changing be evaluated for a thinning cornea. If you have been told you have astigmatism and your glasses never seem right, corneal mapping is the next step.

Can I wear contact lenses with keratoconus?

Most people with keratoconus can wear contact lenses, and specialty lenses are the main way clear vision is restored. MedlinePlus states that contact lenses are the main treatment for most patients and that vision can most often be corrected with rigid gas permeable lenses. Soft lenses work in the early stage; rigid gas permeable, hybrid, and scleral lenses are fitted as the cornea steepens. A lens that stops fitting well is a sign the cornea has changed and the maps should be repeated.

Does keratoconus affect both eyes?

Keratoconus usually affects both eyes, but rarely to the same degree. The American Academy of Ophthalmology states that it often affects both eyes and can lead to very different vision between them, with symptoms that differ in each eye and change over time. Each eye is mapped, corrected, and treated on its own.

Schedule a keratoconus evaluation in Westerville

If your glasses never seem right, your prescription keeps changing, or you have been told you may have keratoconus, a keratoconus evaluation with corneal mapping at our Westerville office is the next step. Comprehensive EyeCare of Central Ohio, founded in 1975, serves Westerville, the greater Columbus area, Worthington, Sunbury, and Lewis Center, with ophthalmologists and optometrists in one building. Call 614-890-5692, or use our contact page to request an appointment. Our office at 450 Alkyre Run Drive, Suite 100, Westerville, Ohio 43082 is open Monday to Friday, 7:00 AM to 4:30 PM, and Saturday, 8:00 AM to 12:00 PM; see appointments and office hours for what to bring.

Keep reading

• Keratoconus ophthalmologist near me: keratoconus care at our Westerville office, including crosslinking, specialty lenses, and corneal transplant.
• Kenneth A. Beckman, MD, Director of Corneal Services: the physician who directs corneal care at our practice.
• Appointments and office hours: how to schedule, what to bring, and what to do after hours.

Sources

• American Academy of Ophthalmology, What Is Keratoconus?, reviewed by Brenda Pagan-Duran, MD, published January 6, 2026, https://www.aao.org/eye-health/diseases/what-is-keratoconus, accessed 10/20/2026.
• MedlinePlus Medical Encyclopedia, Keratoconus, review date July 9, 2024, https://medlineplus.gov/ency/article/001013.htm, accessed 10/20/2026.
• American Academy of Ophthalmology, Corneal Ectasia Preferred Practice Pattern, approved September 22, 2023, Highlighted Findings and Recommendations for Care, https://www.aao.org/education/preferred-practice-pattern/corneal-ectasia-ppp-2023, accessed 10/20/2026.
• U.S. National Library of Medicine, DailyMed, Photrexa Viscous and Photrexa (riboflavin 5′-phosphate ophthalmic solution) for use with the KXL System, prescribing information, https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f82cfe92-1a24-11e3-8ffd-0800200c9a66, accessed 10/20/2026.
• MedlinePlus Medical Encyclopedia, Blindness and vision loss, review date August 5, 2024, https://medlineplus.gov/ency/article/003040.htm, accessed 10/20/2026.
• American Academy of Ophthalmology, What Is Bacterial Keratitis?, reviewed by Omar R. Chaudhary, MD, published July 2, 2026, https://www.aao.org/eye-health/diseases/what-is-bacterial-keratitis, accessed 10/20/2026.
• MedlinePlus Medical Encyclopedia, Eye emergencies, review date April 29, 2025, https://medlineplus.gov/ency/article/000054.htm, accessed 10/20/2026.