It is often disheartening to learn that one has keratoconus. It gives a sort of relief though that finally, you know what is going on. Why your vision keeps on getting worse, and why your vision cannot be improved by glasses anymore. According to the American Optometric Association, keratoconus is a vision disorder that occurs when the normally round cornea (the outer transparent part of the eye) becomes thin and cone-shaped. This irregularity prevents the light entering the eye from being focused correctly on the retina which then causes distortion and blurring of vision. One of the most common questions we encounter is, can keratoconus have 20/20 Vision?
Lazy Eyes? or Keratoconus?
Growing up, parents would notice that there was a need to change the prescription of their child more frequently. It seemed that the prescription was always taken incorrectly, and your child’s astigmatism and nearsightedness got higher with each vision examination. Then eventually, the prescription was not enough to provide the patient the usual coveted 20/20 perfect vision with their glasses or conventional contact lenses. Similar to lazy eyes, a keratoconus patient will not achieve 20/20. The similarity in this may caused the condition to be undiagnosed until at its moderate to late stages.
How To Treat Keratoconus or How To Manage Keratoconus?
Usually, the protocol for managing keratoconus patients would include a discussion about corneal collagen cross-linking that aims in controlling the worsening of the disease. If there is an indication that the keratoconus of the patient is progressing, collagen cross-linking may be performed. In collagen cross-linking, riboflavin (vitamin B2) is administered in conjunction with ultraviolet A which leads to biomechanical stiffening of the cornea. It was shown that this procedure flattens the cornea by about 2 Diopters and may improve vision to about 2 lines or 10 letters. Some patients would delay this procedure, but note that there is a minimum cut-off corneal thickness for the surgeon to still allow to do the procedure for safety purposes. Eye rubbing after the procedure can still cause progression of keratoconus.
Intrastromal corneal ring segments are small, crescent-shaped plastic rings that are placed in the deep, peripheral corneal stroma in order to flatten the cornea. They are made of a material called polymethylmethacrylate (PMMA). This too may flatten the cornea to about 2 Diopters, and may improve uncorrected vision to about 2 – 4 lines as noted in different studies. This is not a must in keratoconus management, however, it may be indicated if contact lenses cannot be fitted due to a very steep cornea.
In the worst cases, a corneal transplant is considered. Only about 28% of keratoconus patients would need corneal transplantation to improve their vision. A corneal transplant is only indicated if vision cannot be improved anymore with contact lenses and if lenses are intolerable already. The average long-term graft survival is nearly 20 years. This means that a young patient can have more than one corneal transplant in a lifetime. Vision with correction will definitely be improved however note that uncorrected, the patient may still have astigmatism. If your keratoconus was severe before the transplantation, it is possible for you to see a dramatic change in your uncorrected vision. Some patients may be happy with their uncorrected vision post-transplant, but most would still need contact lenses to achieve good vision.
Contact Lenses to Improve Vision
In general, to attain good vision, specially designed contact lenses would still be needed after the collagen cross-linking, intrastromal ring implantation and corneal transplant. This is why, before considering corneal transplants, contact lens wear should be initiated to see if vision can still be satisfactory with them. Most often than not, one can achieve good vision with contact lenses.
Vision and Keratoconus
A keratoconus eye is an eye with higher-order aberrations. This caused patients to see blur, haloes and glare. Can keratoconus have 20/20 vision? If the cornea already has a scar, then it may be difficult. We use the analogy of a dirty window from the inside. How much we wipe the window outside will not make the window crystal clear. Some keratoconus can have 20/20 vision though, however, It is good to note that the quality and crispness of the vision will not be the same as an eye without keratoconus. This is evident especially when only one eye has an advanced condition, while the other eye can still use conventional contact lenses. Oftentimes, keratoconus affects both eyes at different magnitudes. This means that one eye would be able to see better than the other thus binocularity may also be affected. Special contact lenses including small GP (gas permeable) lenses, large GP lenses (scleral lens), soft customized contact lenses, and hybrid contact lenses can help in improving vision by masking irregular astigmatism. This will now allow light to be more focused when it enters the eye.
“A Keratoconus Can Have 20/20 Vision, but this is not the default.”
- Javadi M. A., Motlagh B. F., Jafarinasab M. R., et al. Outcomes of penetrating keratoplasty in keratoconus. Cornea. 2005;24(8):941–946. doi: 10.1097/01.ico.0000159730.45177.cd.
- Sykakis E et al. Corneal Collagen Cross-linking for treating keratoconus. Cochrane Database Syst Rev. 2015 Mar 24;93): CD010621.
- Wollensak G, Spoerl E, Seiler T. Stress-strain measurements of human and porcine corneas after riboflavin-ultraviolet-A induced cross-linking. Journal of Cataract and Refractive Surgery. 2003;29(9):1780-1785.
- Zadnik K, Money S, Lindsley K. Intrastromal corneal ring segments for treating keratoconus. Cochrane Database Sys Rev. 2019 May 14.
- Kelly T, Williams KA, Coster DJ, Australian Corneal Graft Registry. Corneal Transplantation for Keratoconus: A Registry Study. Arch Ophthalmol. 2011;129(6):691–697. doi:10.1001/archophthalmol.2011.7
- Kennedy RH, Bourne WM, Dyer JA, 1986. A 48-year clinical and epidemiologic study of keratoconus. Am. J. Ophthalmol 101, 267–273.
- Godefrooij DA et al. Age-specific Incidence and Prevalence of Keratoconus: A Nationwide Registration Study. Am J Ophthalmol. 2017 Mar; 175:169-172.
- Grentzelos MA, Kounis GA, Diakonis VF, Siganos CS, Tsilimbaris MK, Pallikaris IG, Kymionis GD, 2017. Combined transepithelial phototherapeutic keratectomy and conventional photorefractive keratectomy followed simultaneously by corneal crosslinking for keratoconus: cretan protocol plus. J. Cataract Refract. Surg 43, 1257–1262.
About the Author:
Dr. Millette Romualdez is a Fellow of the American Academy of Optometry, Scleral Lens Society, Philippine College of Optometry and International Association of Contact Lens Educators. She has also received a Certification of Advanced Contact Lenses from the Australian College of Optometry.
To book an appointment for a doctor that fits keratoconus contact lenses such as scleral contact lenses, GP lenses and Kerasoft IC , contact us via 09215452389 or firstname.lastname@example.org