What is keratoconus?

Keratoconus is a rare condition that causes a bulging of the cornea. It is associated with a chronic progressive thinning of that portion of the cornea as well. The bulging is caused by the normal pressure of the eye pushing against this weakened area of the cornea. In time, without treatment vision begins to deteriorate to the point that glasses or contacts are no longer an option or a treatment solution. Vision in patients with keratoconus is therefore typically blurry, even with glasses, due to the stretching of the cornea.

The stretching continues to progress until the patient reaches the age between 30 and 40. By that age, the cornea has become stiffer and is less likely to bulge and become irregular.

Soft contact lenses can improve vision in the early stages of keratoconus. As the condition progresses, rigid gas permeable (RGP) contact lenses may be needed. Until now, if RGP contacts became difficult to wear, a corneal transplantation was the last resort.

General Notes on Keratoconus:

  • 10-20% of patients with KC need surgery (lamellar graft or a corneal transplant)
  • Cause: Genetic most likely but /made worse by the environment
  • Eye rubbing likely an important factor
  • Always bilateral as the disease is a deficient corneal cross-linking disease
  • Progresses at different rates in different people
  • Begins in teens, then progresses/, and finally stabilizes between ages 30-35 years
  • Incidence: 1/2,000 people
  • Treatment:
    • RGP (Rigid Gas Permeable) contact lenses
    • Corneal Cross Linking (see CCL)
    • Intacs®;
      • An opportunity to improve functional vision and
      • Defer corneal transplantation in most people with keratoconus
      • Helps correct myopia and astigmatism in keratoconus patients where RGP’s and spectacles no longer provide suitable and functional vision due to contact lens intolerance, thus providing the keratoconus patient with improved functional vision with contact lenses or glasses, all by its flattening effect on the cornea.

Management of Keratoconus

For patients who suffer from keratoconus, a progressive eye disease, Bense Vision™ offers new alternative treatments. Previously, patients with keratoconus relied on corneal transplants when their eyes deteriorated beyond the point at which eye glasses or contacts could assist them.

Now, our patients have two keratoconus treatment options: Intacs® corneal implants and corneal cross linking (CXL). Prior to the use of corneal collagen cross-linking, it is estimated that about 10-20% of keratoconus patients required a corneal transplant.

Current methods of treating keratoconus:

Rigid contact lenses (RGP), can only:

  • Correct the refractive error in some cases, but it has no effect on the progression of the disease.

The Intacs® procedure is however able to:

  • Help restore contact lens tolerance
  • Possibly delay a corneal transplant indefinitely
  • Possibly help delay progression of the disease
  • Help restore functional vision with contact lenses and or spectacles. In most instances, Intacs® improves the best able vision of the patient by helping to correct the myopia and astigmatism in patients with Keratoconus. It is not designed to make patients spectacle independent as with LASIK and or PRK.
  • Help correct this abnormal bulge by flattening the steep portion of the cornea

Corneal collagen cross linking (The application of Riboflavin Eye Drops on the cornea plus UV-A light applied for 30 minutes), is further able to:

  • Increases the mechanical strength of the stroma. This is responsible for further preventing the cornea from bulging out and becoming steep and irregular.
  • This can cause s lowing down of the disease process, delay and or even halt the progression of keratoconus by stiffening and bonding the fibers in the cornea, thus preventing keratoconus from getting worse.
  • Dramatically improving vision without the need for a corneal transplant in some cases.

Treatment Options for Keratoconus:

A: CONTACT LENSES

Patients with very mild disease may initially be corrected with glasses or soft contact lenses; however the vast majority of patients with keratoconus need rigid contact lenses (RGP lenses) for adequate vision correction. There are a variety of types of specialized rigid contact lenses and depending on the contact lens fitters experience or expertise they will describe the one best suited for you. The very latest contact lens for treating keratoconus is one that is rigid in the middle and soft on the edges. This has the potential to give you the good quality vision of the rigid lens with some of the comforts of the soft lens. It is best to go to an optometrist who specializes in fitting lenses for keratoconus in your area. We would be happy to refer you to one should you so desire. It is always a good idea to try several different contact lenses and fitters before giving up on them and embarking on surgery.

Many patients find their contact lenses uncomfortable and can only tolerate their contact lenses for a few hours a day. The reason this happens is that the cornea shape changes by steepening. This creates several problems like the cornea rubbing against the lens which can cause irritation, photophobia, dry eye problems (tears dislike a steep cornea because it has to run uphill), or an abrasion. Dry eye problems so common in these patients contribute to the patient being uncomfortable and developing contact lens intolerance.

There are now many ways to treat dry eyes to improve contact lens tolerance. This includes the use of artificial tears, treating the lids for lid disease, Restasis eye drops to help increase tear production and the use of punctal plugs to prevent tears from draining down your naso-lacrimal ducts and keeping the eye moist.

Sometimes a little scar appears on the tip of the cornea that constantly rubs against the lens making it difficult to tolerate contact lenses. This scar can be removed with a blade or with a laser using the PTK method. This can help the patient return to contact lens tolerance.

B: Intacs® for Keratoconus and Post Laser (LASIK/PRK) Ectasia

For the keratoconus patient having 20/40 vision for only a few hours of the day due to painful contact lens wear, Intacs® are the new standard of care. Intacs® corneal implants can now potentially defer the need for a corneal transplant.

Historically, doctors didn’t have a choice. Once a patient became intolerant of contact lenses or glasses, their only option was to undergo a corneal transplant. Today, surgeons around the world are choosing a less invasive standard of care and achieving excellent results with Intacs® corneal implants.

Intacs corneal implants are a Canada Health approved option for the keratoconus patient who is in-between contact lenses and a corneal transplant i.e. patients or individuals experiencing some degree of intolerance to contact lens and could some day possibly be facing a corneal transplant. Intacs corneal implants may be the best possible option to stabilize the cornea, improve vision and potentially defer the need for a corneal transplant.

This procedure is thus good for patients who are contact lens intolerant and who want to avoid a corneal transplant and are otherwise good candidates for this procedure. It is also useful for individuals with keratoconus who want to improve their present vision with or without contact lenses or possibly switch from hard contact lenses to soft contact lenses.

Bense Vision uses the Intralase laser for making the channels to insert the plastic segments. We also use the manual (Prolate) technique when needed. The Prolate mechanical technique involves using metal blades, so the IntraLase system is safer.

Intacs corneal implants are also indicated for use in the correction of nearsightedness and astigmatism associated with keratoconus where contact lenses and glasses are no longer well tolerated.

Goal of Intacs®:

  • To help restore contact lens tolerance
  • Delays a corneal transplant indefinitely in some cases
  • To restore functional vision with contact lenses and or spectacles. In most instances, Intacs® improves the best able vision of the patient by helping to correct the myopia and astigmatism in patients with Keratoconus. It is not designed to make patients spectacle independent as with LASIK and or PRK.

How does this Intacs® procedure create the intended benefits?

  • By correcting this abnormal bulge in the cornea by flattening the steep portion of the cornea, thus fixing vision irregularities. If properly placed, Intacs® segments can reduce these irregularities caused by keratoconus without removing tissue. Intacs® corneal implants do not replace the cornea; rather, they are implanted within the existing cornea to provide keratoconus treatment. Intacs® are made from the same material used to produce contact lens implants (or intraocular lenses) and do not cause much risk of negative reactions.
  • It is likewise believed by many corneal surgeons that Intacs may possibly delay the progression of keratoconus.
  • Intacs® offer a treatment option between contacts and corneal transplants.

Benefits of using Intacs® as our Corneal Segment of choice:

  • Excellent safety
  • The implant of choice for most corneal surgeons
  • Fast and minimally invasive procedure
  • Clinically established treatment
  • Supported by many peer-reviewed articles
  • Implanted outside optical zone
  • Security of removability
  • Used in many countries
  • Health Canada approved
  • Cornea has more natural dome shape
C: Corneal Cross Linking (CXL)

To stop the progression of Keratoconus

This treatment has the potential to stop the progression of keratoconus. This treatment is recommended for individuals with progressive Keratoconus or Ectasia following LASIK to stabilize the cornea. It can be performed with our without INTACS.

This non-invasive treatment (corneal collagen cross-linking with riboflavin) treatment has been proven to strengthen the weak corneal structure in keratoconus. This method works by increasing collagen cross-linking within the cornea. This is responsible for preventing the cornea from bulging out and becoming steep and irregular.

During the 60-minute, in-office treatment, custom-made riboflavin eye drops are applied to the cornea. Once it has been shown to have entered the anterior chamber of the eye, the eye is then activated by a special light. This is the process that has been shown in laboratory and clinical studies to increase the amount of collagen cross-linking in the cornea and strengthen the cornea. In published studies, such treatments were proven safe and effective in patients.

D: CXL and Intacs® combined

Corneal Cross Linking treatments can also be combined with Intacs® to flatten the keratoconus cone even more than with Intacs alone. In these cases, Corneal Cross Linking treatments stabilize keratoconus from getting worse as well as help the Intacs® reverse the keratoconus steepening that had already occurred up to the time of the treatment.

E: ICL

Implantable Contact Lens

When a patient requires vision correction, but the cornea is too thin or the prescription is too high for laser vision correction, the Implantable Contact Lens (ICL) is an option to consider. Patients with early stages of keratoconus have benefited from the Implantable Contact Lens.

Patients who are extremely nearsighted i.e. more than -10D might benefit from these phakic intraocular lenses. This lens has been approved by for up to -20 Diopters. This treatment is readily available in Canada and we will gladly refer you to a surgeon that is an expert in this technique. This is an exciting new opportunity for a select number of patients with keratoconus who could potentially improve their vision without the need for laser surgery.

F: PRK

In some cases, PRK is a reasonable option for patients with keratoconus:

  • Following corneal collagen cross linking for vision correction.
  • PRK for Early Keratoconus. Many eye care professionals recommend against PRK in patients with early keratoconus because it thins the cornea even further, but this treatment has been available to Canadian patients for years as long as they are aware of the risks involved. The disease generally has stopped progressing at age 40 years. In patients with no associated vision loss, stable 20/20 vision, and in patients whose corneas are thick enough to undergo PRK, can be offered this treatment with special informed consent that outlines the potential risks involved.Bense Vision™ is committed to offering the latest, safest procedures to our patients. We believe that these two new keratoconus treatment options at our practice (CXL and Intacs®) allow for the best possible results. Contact our offices to learn more about Intacs® and corneal cross linking today.
G: CORNEAL TRANSPLANTS

Corneal Transplants are the only option for patients who have significant scarring in the center of the cornea or who are contact lens intolerant because their corneas are too steep and are not candidates for Intacs® and or CXL.

Corneal Transplants in the USA

  • 4771/pa
  • 85% success
  • Problems encountered:
    • Graft rejection
    • Persistent astigmatism +++
    • Endothelial cell loss (70%)
    • Frequent disease recurrence
    • Young patients need to be told that a repeat PK is highly likely

The results of corneal transplants are excellent in keratoconus patients with an over 85% success rate.

Of late, the Femtosecond Laser is being used in Canada and elsewhere for performing Intralase Enabled Keratoplasty (IEK), a laser type of corneal transplant. The results are better than traditional transplants.

Sometimes patients who have had a successful transplant with a clear cornea still do not see well and cannot tolerate contact lenses. The reason for this is that they have large amounts of irregular astigmatism following their transplant surgery. This can be corrected by several surgical techniques like Astigmatic Keratotomy (AK), LASIK or PRK on their transplants after the surgery and become relatively independent of glasses or contact lenses. This procedure called PTK, is covered by MCP when there is a significant amount of irregular astigmatism present that prevents visual restoration. Many our patients achieve 20/30 or better vision with this combination of procedures and in most instances, these patients then become either contact lens tolerant and can see better with glasses or contact lenses.

H: LAMELLAR CORNEAL TRANSPLANTS

Treatments that are less commonly performed include lamellar corneal transplants for keratoconus patients who are extremely nearsighted. In a lamellar corneal transplant, only a part of the cornea is removed and is replaced. This is slightly safer than a full thickness transplant however patients do not have the same quality of vision as patients who have undergone full thickness transplants.