Cornea shape condition
Keratoconus
Keratoconus can cause increasing blur, distortion, glare, and changing astigmatism.
Keratoconus is an eye condition where the normally smooth, round cornea gradually becomes thinner and more cone-shaped.
The cornea is the clear front window of the eye. When its shape becomes irregular, light does not focus neatly, which can make vision blurry, distorted, or harder to correct with ordinary glasses.
How keratoconus affects vision
Keratoconus affects the way the cornea focuses light into the eye.
Irregular astigmatism
The changing corneal shape can create irregular astigmatism, which may be harder to correct with standard glasses.
Blur and distortion
Vision may become blurred, doubled, ghosted, smeared, or distorted, especially in low light or with bright lights.
Changing prescription
Frequent prescription changes, increasing astigmatism, or reduced clarity despite new glasses can sometimes be warning signs.
Eye rubbing can make keratoconus worse
People with keratoconus, or suspected keratoconus, are usually advised to avoid rubbing their eyes. If itchy or allergic eyes are a problem, it is better to manage the itch rather than rub.
Corneal thinning and bulging
In keratoconus, the cornea can gradually thin and bulge forward. This can make the front surface of the eye less regular.
Because the cornea provides much of the eye’s focusing power, even small changes in its shape can affect the quality of vision.
Keratoconus can affect each eye differently, and one eye may change more than the other.
Do not ignore increasing distortion or rapid prescription change
Blurry or distorted vision does not always mean keratoconus, but increasing astigmatism, frequent prescription changes, ghosting, halos, or reduced clarity should be checked.
Sudden vision changes, eye pain, injury, flashes, floaters, or a curtain or shadow in the vision should be assessed promptly.
Possible signs of keratoconus
Symptoms vary depending on the stage of keratoconus and how regular or irregular the cornea has become.
Blurred or distorted vision
Vision may look smeared, stretched, shadowed, or doubled, even when wearing glasses.
Glare and halos
Night driving, bright lights, glare, halos, and light sensitivity may become more noticeable.
Frequent lens changes
Repeated changes in prescription, especially increasing astigmatism, may need further corneal assessment.
The cornea is a key focusing surface
In a normal eye, the cornea and lens help focus light onto the retina at the back of the eye.
If the cornea becomes irregular, light may focus unevenly. This can cause blur, distortion, glare, and reduced quality of vision.
A full eye exam helps check whether blur is due to a simple prescription change, dry eye, keratoconus, or another eye condition.
Who can be affected?
Keratoconus is often first detected in teenagers or young adults, but it can be diagnosed at different ages.
Teenagers and young adults
Keratoconus often begins during the teenage years or early adulthood, when prescription changes may start to become noticeable.
Family history
Having a family history of keratoconus can increase the importance of checking for early corneal changes.
Allergy and eye rubbing
Itchy eyes, allergies, and frequent eye rubbing can be relevant and should be discussed during an eye exam.
How keratoconus is checked
Keratoconus assessment may involve several parts of an eye examination.
Vision and prescription
We check your vision, prescription, astigmatism, and whether the vision can be corrected clearly with glasses.
Cornea examination
The front surface of the eye is examined for signs of corneal thinning, irregular shape, scarring, or other changes.
Imaging and referral
If keratoconus is suspected, further corneal imaging or referral may be recommended, depending on the findings.
Glasses, contact lenses, and specialist care
In earlier keratoconus, glasses or soft contact lenses may provide useful vision. As the cornea becomes more irregular, specialty contact lenses may be needed to improve vision.
Rigid gas permeable lenses, hybrid lenses, or scleral lenses may be used in some cases. These require careful fitting and follow-up.
Treatment and monitoring options
Management depends on the stage of keratoconus, whether it is changing, and how well vision can be corrected.
Monitoring
If keratoconus is mild or suspected, monitoring may be recommended to check whether the corneal shape is stable or changing.
Corneal cross-linking
Corneal cross-linking may be considered by an eye specialist to slow or reduce progression in suitable cases.
Surgery in advanced cases
In more advanced keratoconus, specialist treatment such as corneal ring segments or corneal transplant may be considered.
Cross-linking is time-sensitive when keratoconus is progressing
Corneal cross-linking is generally considered when keratoconus is showing signs of progression. If keratoconus is suspected in a young person, it is important not to delay assessment and referral where needed.
The decision about cross-linking is made with an eye specialist after appropriate corneal testing.
Related eye health information
Keratoconus can overlap with other focusing and eye health topics.
Astigmatism
Keratoconus can cause irregular astigmatism, which may be harder to correct than regular astigmatism.
Contact lens exams
Contact lenses for keratoconus often need careful fitting, review, and ongoing monitoring.
Our eye exam standard
A full eye exam helps check prescription, vision quality, and eye health.
Can keratoconus be corrected with glasses?
Glasses may help in early keratoconus. As the cornea becomes more irregular, contact lenses or specialist care may be needed.
Is keratoconus the same as astigmatism?
No. Astigmatism describes uneven focusing. Keratoconus is a corneal condition that can cause irregular astigmatism.
Can keratoconus get worse?
It can progress, especially in younger people. Monitoring helps check whether the cornea is stable or changing.
Should I stop rubbing my eyes?
Yes. If keratoconus is present or suspected, avoiding eye rubbing is important. If your eyes are itchy, ask about safer ways to manage the itch.
Concerned about keratoconus?
You can book online, phone us, or call in and see us at Waipapa Eyecare.
For urgent eye problems, sudden vision changes, flashes, floaters, eye pain, or injury, please phone us rather than using online booking.