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Corneal Cross Linking | Keratoconus

Corneal Cross Linking Treatment for Keratoconus in San Antonio

Corneal cross linking, also called corneal collagen cross-linking, is a treatment that can prevent or slow down the progression of a corneal eye disease called keratoconus. Our experienced eye doctors at Parkhurst NuVision offer corneal cross linking in San Antonio, Texas.

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What is Keratoconus?

Keratoconus is a type of corneal ectasia, which means it is an eye disease that affects the corneal tissue. In keratoconus, the cornea becomes thin and starts to protrude forward causing the eye to form into a cone-shape. The cone-shaped cornea causes irregular astigmatism, which means the light that passes through this cone-shaped cornea becomes distorted. The distorted light can cause halos, starbursts, blurred vision (even with glasses or contacts), double vision, and ghosting. The biggest problem with keratoconus is that it is progressive in nature. Early keratoconus can progress into advanced keratoconus, which could lead to a significant loss of vision and the need for a corneal transplant.

What Causes Keratoconus?

While some experts think patients are born with a certain predilection to keratoconus (and we actually have a genetic test that we offer at our practice to see if you have any of the keratoconus genetic factors), most agree that the only significant risk factor is rubbing of the eyes. Multiple episodes of eye rubbing exerted onto the cornea, can cause corneal deformation and thinning of the cornea, which then can lead to keratoconus. If you only take one thing away from this information—please avoid rubbing your eyes!

Symptoms of Keratoconus

Typically once keratoconus occurs, patients go into their eye doctors office reporting the following keratoconus symptoms:

  • Distorted vision
  • Halos or starbursts around light
  • Blurred vision even with glasses or contacts
  • Vision not correctable to 20/20
  • Double vision
  • Ghosting

Eye exam tests for keratoconus can include corneal topography, corneal tomography, epithelial thickness mapping, keratometry, astigmatism measurements, and retinoscopy.

small icon of eye .. an eyecon

If your doctor suspects keratoconus they can image the cornea to evaluate if it truly has a cone shape.

What is Corneal Cross Linking?

Corneal cross-linking was approved in 2016 by the FDA for progressive keratoconus. Corneal cross linking, sometimes referred to as CXL, is a keratoconus treatment that can prevent or slow down the progression of keratoconus.

The corneal cross linking surgery is centered on making the cornea stronger. Keratoconus causes the cornea to become thinner and weaker, so the goal of this procedure is to make the cornea stronger. We can make the cornea stronger with more covalent bonds in the cornea with cross linking. In order for this process to happen we need two ingredients: riboflavin and UV light.

Young woman smiling

Types of Corneal Cross Linking

There are two types of cross linking procedures: Epithelium-off cross-linking and Epithelium-on cross-linking. However, only epithelium-off cross-linking performed with a Glaukos iLink KXL System is FDA approved for use in the U.S.

Epithelium-off corneal cross linking procedure involves temporarily disrupting the top layer of your cornea with a soft brush or similar device. Then vitamin b2 eye drops, called riboflavin, are applied to the eye for 30 minutes. This allows for the eye drops to completely soak into the cornea. After this, a device is used to project ultraviolet light onto the surface of your eyes for another 30 minutes. The UV light combined with the riboflavin can increase the strength of the collagen fibers in the cornea.

close up of eye

What to Expect During Cross Linking

  • Procedure
  • Recovery

Cross Linking Procedure

During this one hour long procedure your eyes will be numbed, so typically patients do not feel anything during the procedure. Most patients bring headphones to listen to music or listen to a podcast during the procedure. A bandage contact lens is placed on the eye typically for the first week after the procedure as the eye heals.

extreme close up of eye

Cross Linking Recovery

After corneal cross linking, a patient will be on an antibiotic drop for a week and a steroid eye drop for a few weeks after the procedure. Patients will typically avoid water, sweat, and make up in and around the eyes for the first week. The first few days after the procedure can be uncomfortable as the eye heals, so you will want to allow a few days off from work as you recover.

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Four Facts About Cross Linking for Keratoconus

  1. Corneal Cross Linking works best if used as a treatment for patients who have mild keratoconus. By cross linking the cornea early, we can stop the worsening of the disease and allow mild keratoconus to stay as mild keratoconus. If we cross link the cornea when there is moderate keratoconus, it will keep the cone shape as moderate keratoconus.
  2. Epithelial off corneal cross linking is the only FDA approved keratoconus treatment option for progressive keratoconus. FDA-approval means that your insurance could possibly cover the procedure.
  3. Corneal cross linking is safe and effective. In the two corneal cross linking studies submitted to the FDA, patients who had corneal cross linking for progressive keratoconus, on average, had a flattening of the cone shape by 1.4 diopters and 1.7 diopters at month 12. This means after epithelial off corneal cross linking the cone shape of keratoconus did not progress on average but rather became less cone-like. The progressive keratoconus group that did not get corneal cross linking continued to progress by 0.5 diopters in study 1 and 0.6 diopters in study 2 at month 12. In the study, <2% of patients had corneal inflammation or opacity, reduced visual acuity, corneal striae, or blurred vision.
  4. A goal of corneal cross linking is to avoid a corneal transplant. Keratoconus is a progressive disease in most patients.2 If a patient’s keratoconus continues to advance, the cornea shape will continue to change and distort the light coming in. The advancement of specialty contact lenses have helped so many keratoconus patients, especially advanced keratoconus patients, have functional vision. However, keratoconus can progress to a point where even specialty contact lenses can’t help with vision. When a patient has severe vision loss from keratoconus and can’t be helped with specialty lenses, then a corneal transplant should be considered. A corneal transplant involves the removal of the central part of the cornea and replacing it with a matched donor button of the cornea. In this photo of a corneal transplant, the stitches can be seen, as this helps to keep the donor cornea in place. The healing process following a cornea transplant can be long, often taking a year or longer. The stitches are most commonly removed 6 to 17 months after the procedures. Steroid eye drops may be needed for months and sometimes years after a corneal transplant.1

Frequently Asked Questions About Corneal Cross Linking

Can Cross Linking be performed on patients with advanced keratoconus?

A recent study found that “despite advances in diagnostic tools keratoconus is often diagnosed at a relatively late stage.”3 Currently we see more advanced keratoconus patients getting corneal cross linking, because it is being diagnosed at a later stage. If there is any suspicion you may have keratoconus, we recommend getting scans to see if you have keratoconus. Remember, the earlier we diagnose keratoconus, the earlier we can do corneal cross linking.

Does Corneal Cross Linking correct your vision?

When we do corneal cross linking, the flattening of the cone shaped cornea can allow for the vision to get better after corneal crosslinking. Will you notice the improvement in vision? That depends on the severity of the keratoconus. Most of the time, patients do not notice the slight improvement in vision after corneal cross linking. To achieve your best vision before or after corneal cross linking you will likely need a specialty contact lens. Corneal cross linking will not eliminate the need for a specialty contact lens.

Are There Vision Correction Procedures for Patients with Keratoconus?

At Parkhurst NuVision, we do have vision correction solutions for patients with keratoconus who would like less dependence on glasses and contacts. The three vision correction procedures that you could consider with keratoconus are: EVO ICL, topography guided PRK, and INTACS.

ICL is a surgery where a lens is placed just beneath the surface of the eye. It can correct high amounts of myopia and high amounts of regular astigmatism, both which are seen in keratoconus patients.4 The ICL does not make any big changes to your cornea, so this is our most popular option for keratoconus patients wanting better vision without contacts or glasses. A recent study compared INTACS to ICLs and showed that ICLs were more stable and provided more predictable vision results.5

Topography guided PRK is gaining traction both in the United States and outside the United States as a treatment option for keratoconus patients. Topography guided PRK uses a laser to reshape the cone shape to a more natural shape. In order to reshape the cornea with topography guided PRK the laser will need to remove the tissue causing the abnormal shape. We have to remember keratoconus causes patients to have a thinner cornea, so this procedure can be done only if you have enough corneal thickness. This procedure will also not be ideal for advanced keratoconus or those with a very cone shape, the laser will not be able to normalize the shape in these eyes. Topography Guided PRK can be done at the same time of corneal cross linking or can be done after cornea cross linking. These two can work very well together as corneal cross linking makes the cornea strong and topography guided PRK makes the cornea a more normal shape.6 Corneal crosslinking, topography guided PRK, and ICLs may need to all be combined in order to give the best possible vision without glasses or specialty contact lenses.7

INTACS are an intrastromal ring that is inserted into the middle part of the cornea in eyes with keratoconus to provide structural support to the thin cornea. INTACS attempt to improve the corneal shape and provide slightly better uncorrected vision for those with keratoconus. Typically INTACS are used for patients who can no longer fit in their specialty contact lenses due to their cornea becoming an advanced cone shape. These patients want to try something before doing a corneal transplant and intacs could be a solution. These patients need to be watched closely over time, because the cornea can have excessive inflammation after this procedure.

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Contact Parkhurst NuVision

To know what procedure or procedures are best for you, we recommend a keratoconus evaluation. In this evaluation we will evaluate the front shape of your eye, get an idea of your prescription, and recommend the best keratoconus surgical treatment for you. Contact us or call us at 210-585-2020 to schedule a consultation appointment.

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1 Belin MW, Lim L, Rajpal RK, Hafezi F, Gomes JAP, Cochener B. Corneal Cross-Linking: Current USA Status: Report From the Cornea Society. Cornea. 2018 Oct;37(10):1218-1225. doi: 10.1097/ICO.0000000000001707. Erratum in: Cornea. 2019 Oct;38(10):e49. PMID: 30067537.
2 Chatzis, Nico, and Farhad Hafezi. “Progression of Keratoconus and Efficacy of Corneal Collagen Cross-Linking in Children and Adolescents.” Journal of Refractive Surgery, vol. 28, no. 11, 11 Oct. 2012, pp. 753–758.,
3 ​​Kreps EO, Claerhout I, Koppen C. Diagnostic patterns in keratoconus. Cont Lens Anterior Eye. 2021 Jun;44(3):101333. doi: 10.1016/j.clae.2020.05.002. Epub 2020 May 21. PMID: 32448765.
4 Kalra, Nidhi, et al. “Posterior Chamber Phakic Intraocular Lens Implantation for Refractive Correction in Corneal Ectatic Disorders: A Review.” Journal of Refractive Surgery, vol. 37, no. 5, 1 May 2021, pp. 351–359.
5 Ramin S, Sangin Abadi A, Doroodgar Fet al.. Comparison of visual, refractive and aberration measurements of INTACS versus Toric ICL lens implantation; a four-year follow-up. Med Hypothesis Discov Innov Ophthalmol. 2018; 7(1):32–39.29644243.
6 Nattis, Alanna S. DO, FAAO; Rosenberg, Eric D. DO, MSE; Donnenfeld, Eric D. MD One-year visual and astigmatic outcomes of keratoconus patients following sequential crosslinking and topography-guided surface ablation: the TOPOLINK study, Journal of Cataract and Refractive Surgery: April 2020 – Volume 46 – Issue 4 – p 507-516. doi: 10.1097/j.jcrs.0000000000000110
7 Sakla, Hani F., et al. “Visual and Refractive Outcomes of Toric Implantable Collamer Lens Implantation in Stable Keratoconus after Combined Topography-Guided PRK and CXL.” Journal of Refractive Surgery, vol. 37, no. 12, 1 Dec. 2021, pp. 824–829.,

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