Frequently Asked Questions
- I have keratoconus, will I go blind?
- I'm 15 and have just found out that I have keratoconus. Is the cone very noticeable to other people?
- Is it possible for keratoconus to simply get better and heal on its own, or is it a permanent condition that can only degenerate?
- Is my keratoconus going to get worse and how quickly will it change?
- Keratoconus has been confirmed in my right eye. Will my left eye be affected also?
- Will certain activities, such as sports or long hours in front of the computer, hasten the progression of keratoconus?
- Why is my vision sometimes more than "double"? I only have 2 eyes so where do the other images come from?
- What is the difference between keratoconus and "common astigmatism"?
- What is the meaning of the numbers used to describe the degree of astigmatism?
- What is the best contact lens for keratoconus?
- Can I still wear soft lenses if I have keratoconus?
- My friend wears soft contact lenses for her short sightedness. Why can't I wear soft lenses for my keratoconus?
- I am going on 58 and have just been diagnosed with keratoconus. My doctor has recommended contact lenses but I've never worn them before and I'm worried that I may not be able to handle them at my age.
- Can I take advantage of different brands of contact lens solutions and eye drops, depending on what's on sale?
- Recently I have noticed a 'general fog' which affects my vision like my lens is not clean. This usually comes on after a few hours of contact lens wear. What would cause this?
- Some GP keratoconus lenses have aberration control incorporated into their design. Is this necessary and what advantages does this have over lenses that do not have aberration control?
- I've had transplant surgery and I've been told to expect changes in my vision for many months. How long should it take for my eye to stabilize, and is the astigmatism likely to get better or worse as my eye continues to heal? Also, will I need contact lenses after surgery?
- Can I have LASIK?
- My lenses become uncomfortable in airplane cabins. What can I do?
Q: I have keratoconus, will I go blind?
A: No, keratoconus is not a blinding condition, although vision is likely to progressively worsen. Keratoconus causes thinning and distortion of the cornea, which is the clear dome at the front of the eye. The cornea normally has a rounded dome-like shape, but in keratoconus the thinned area bulges forward to produce a cone-like protrusion. This results in distortion and reduced vision, blurred distance vision, glare, light sensitivity and distrubed night vision. However with the use of contact lenses, most keratoconus patients can maintain good functional vision and a normal lifestyle. Back to Top
Q: I'm 15 and have just found out that I have keratoconus. Is the cone very noticeable to other people?
A: The corneal changes in keratoconus are so subtle that special instruments and training are required to see them. Except in the most advanced cases, it is virtually impossible for someone other than a doctor to tell that you have keratoconus. Back to Top
Q: Is it possible for keratoconus to simply get better and heal on its own, or is it a permanent condition that can only degenerate?
A: Keratoconus either progresses or remains stable: it does not get better. Back to Top
Q: Is my keratoconus going to get worse and how quickly will it change?
A: Keratoconus invariably does get worse in the majority of cases, however progression is difficult to predict. In some cases it changes very little from the time it is first diagnosed. In other cases progression occurs rapidly over a relatively short period of time. The younger the patient is when keratoconus first appears, however, the more chance there is that it will progress significantly, particularly during the teenage years. It is very important to control any allergies which affect the eye during this time, so that any eye rubbing can be avoided. Back to Top
Q: Keratoconus has been confirmed in my right eye. Will my left eye be affected also?
A: Keratoconus is bilateral (i.e. affects both eyes) in about 97% of all cases. Only about 3% of cases are truly unilateral. A topography or mapping of the cornea by your practitioner will nearly always show some steepening in the unaffected eye at the time of the first diagnosis of keratoconus, even though the vision in this eye at this stage may be unaffected. Frequently one eye will show symptoms before the other, and the degree of severity is normally worse in one eye and often remains this way. Back to Top
Q: Will certain activities, such as sports or long hours in front of the computer, hasten the progression of keratoconus?
A: There is no evidence that any physical or visual activity has any affect on the progression of keratoconus. The exception is eye rubbing where the trauma caused by rubbing the eye can damage the cornea which may cause the condition to advance more rapidly. Back to Top
Q: Why is my vision sometimes more than "double"? I only have 2 eyes so where do the other images come from?
A: Multiple images can be caused by a disparity between the two eyes or from multiple refractive zones within the optical zone of just one eye. If you see double and it disappears when you close either eye, it is most likely a binocular problem caused by the two eyes not working together. The causes of this are many and some are potentially serious. Mulitple images in one eye occur more frequently in ocular surface diseases like keratoconus or in diseases affecting the lens or iris of the eye. In keratoconus, surface thinning can create multiple optical zones that individually focus the same image to different areas of the retina, thus creating the additional perceived images. Contact lenses usually eliminate most of these problems. Back to Top
Q: What is the difference between keratoconus and "common astigmatism"?
A: Astigmatism is a common condition where the curvature of one or more of the optical surfaces of the eye (the cornea and lens surfaces) are more "curved" in one direction than the other. In "regular" astigmatism the maximum and minmum powers of the cornea are aligned at 90 degrees to each other, while in "irregular" astigmatism they do not align. An egg is a good example of a surface with regular astigmatism, whereas an orange (sphere) is a good example of a surface which has no astigmatism. Keratoconus is a degenerative condition where the cornea thins in affected areas. This can lead to astigmatism, often regular at first but becoming increasingly irregular as the condition progresses. It is possible to correct regular astigmatism with glasses or soft contact lenses. However for irregular astigmatism, where the cornea can often have multiple curves (giving multiple focuses), it is impossible to correct these multiple focuses with spectacles or soft contact lenses. Back to Top
Q: What is the meaning of the numbers used to describe the degree of astigmatism?
A: Astigmatism is measured in diopters (D), a standard optical measure. In simple terms, the diopter represents the reciprocal of the focal distance in meters. For example, a patient with 2 D of nearsightedness would have a far focal point of 1/2 meter. A patient with 4 D would have a focal length of 1/4 meters or 25 cm. A patient with 1/2 D would have a focal point 2 meters in the distance. Many patients have between 0.25 and 2.00 D of astigmatism. Between 2.25 and 3.75 is less common but still seen. Much above that in a "normal" patient is unusual. Keratoconus and post-transplant patients can have up to 10 D of more of astigmatism. Back to Top
Q: What is the best contact lens for keratoconus?
A: There is no single lens type or brand that works for every keratoconus patient. In the early stages, conventional soft lenses can work remarkably well. As keratoconus progresses, gas permeable (GP) lenses work best for the majority of patients. In other cases where tolerance of a GP lens is a problem, piggybacking a rigid lens over the top of a soft disposable lens can, in many cases, improve the tolerance dramatically and provide successful contact lens wear. Unfortunately, contact lenses alone may not completely correct your vision. For some patients, spectacles worn over contact lenses or special lens designs may help. In some cases, corneal scarring or other problems may limit vision, and no amount of correction will be completely effective. Surgery may be the best choice when the vision obtained with a contact lens correction is inadequate. Back to Top
Q: Can I still wear soft lenses if I have keratoconus?
A: Soft contact lenses may work well in early keratoconus. In more advanced cases they will do no harm but they rarely provide adequate visual correction. GP contact lenses usually offer better vision correction for keratoconus. Back to Top
Q: My friend wears soft contact lenses for her short sightedness. Why can't I wear soft lenses for my keratoconus?
A: Unfortunately, soft contact lenses very rarely provide the same standard of vision that GP lenses provide. By nature, soft lenses wrap around the cornea giving rise to that same optical issues (distorted vision) that the keratoconus cornea causes. A GP (rigid) lens provides a new optical surface for light entering the eye, so light can be focused back to a single point. However, in some early cases of keratoconus where the corneal distortion is minimal, soft lenses can provide an acceptable standard of vision. Back to Top
Q: I am going on 58 and have just been diagnosed with keratoconus. My doctor has recommended contact lenses but I've never worn them before and I'm worried that I may not be able to handle them at my age.
A: Give contact lenses a try. Handling lenses is far less difficult than you would imagine and the improvement in your vision is likely to be subtantial. Make sure that you find a contact lens specialist who is patient and is willing to take the time needed to properly train you on how to insert and remove your contact lenses and how to care for them. With sufficient training it would be most unusual that lens handling would prevent you from being able to use contact lenses. Back to Top
Q: Can I take advantage of different brands of contact lens solutions and eye drops, depending on what's on sale?
A: Recently published research has shown significant incompatabilities between newer contact lens materials and some contact lens care products. The result is irritation and increased risk of more serious problems. Clearly, not all care products are the same. You should avoid problems by first checking with your contact lens specialist before switching lens care products. Back to Top
Q: Recently I have noticed a 'general fog' which affects my vision like my lens is not clean. This usually comes on after a few hours of contact lens wear. What would cause this?
A: Fogging can be caused by a build-up of deposits on the surface of the contact lens, or by some physiological change to the cornea. If fogging occurs, always remove the lens, clean it with a GP cleaner such as MeniCare Plus, re-wet the lens and reinsert it. If the fogging problem is resolved then this was obviously due to some build-up on the lens surface. However if the fogging persists, then it is likely to be due to some change in the cornea such as edema, where the cornea swells and becomes less transparent. In this case you should consult your contact lens fitter as soon as possible to determine the cause of your symptoms. Back to Top
Q: Some GP keratoconus lenses have aberration control incorporated into their design. Is this necessary and what advantages does this have over lenses that do not have aberration control?
A: The most common type of lens aberration is spherical aberration and it is caused by two lens surfaces not being parallel, the front surface of the lens being significantly flatter than the back surface. This causes light passing through different points on the lens to have different focal points onto the retina (back of the eye) and produces a 'ghost' image around the original image like a television set that is not tuned properly. By subtly changing the curves on the surface of the lens, a significant amount of the spherical aberration can be eliminated. The amount of spherical aberration produced is proportional to the lens power, so as keratoconus gets worse, the lens power also needs to increase and the spherical aberration increases likewise. Keratoconus patients commonly require very high powers on their lenses to see well and therefore obtain significant benefit from having aberration control incorporated into their lenses. The Rose K2 lens (and also the IC, PG, and NC designs) is an example of a lens which has aberration control. In a study in the USA, where a group of over 50 patients wore Rose K lenses both with and without aberration control, 100% reported their vision with Rose K2 to be the same or better than the original Rose K design which did not incorporate aberration control, and 75% of patients reported their vision with Rose K2 to be better or much better. Many patients gained at least one line of vision which is very significant. Back to Top
Q: I've had transplant surgery and I've been told to expect changes in my vision for many months. How long should it take for my eye to stabilize, and is the astigmatism likely to get better or worse as my eye continues to heal? Also, will I need contact lenses after surgery?
A: Healing and refractive results after transplant surgery vary tremendously from patient to patient making it difficult to predict results. There is also no way to know if a contact lens will be necessary until your eye is stable. In addition to contact lenses and glasses, several adjunctive surgical procedures can be performed to reduce post-transplant astigmatism if needed. The majority of patients can obtain reasonable vision with spectacles, however for both eyes to work together to give good binocular vision, a contact lens is still often required. Back to Top
Q: Can I have LASIK?
A: No, keratoconus is a corneal thinning condition and LASIK is a corneal thinning procedure. Surgically making a thin cornea thinner will weaken an already weak cornea and speed the progression of keratoconus thereby exacerbating the condition. Back to Top
Q: My lenses become uncomfortable in airplane cabins. What can I do?
A: Ideally one would never wear any contact lenses in an airplane cabin because of the reduced oxygen available and the very low humidity. This is certainly not an ideal environment for contact lens wear. Both of these factors invariably lead to dryness, irritation, discomfort and subsequent reduced wearing time. However for the keratoconic patient, leaving the lenses out when flying is often not an option as their uncorrected vision is insufficient for them to manage. Therefore while flying, we recommend frequent (at least hourly) use of contact lens rewetting drops, removal of lenses if sleeping, and removal of the lenses even for short periods to clean and re-wet the lens if this is a possible option. Also, keep your body hydration levels to a maximum by drinking plenty of water and avoiding alcohol and coffee, both of which cause dehydration. Back to Top
Our special thanks to the National Keratoconus Foundation for providing much of the information contained on this page.