Astigmatic Incisions

 Astigmatic Incisions are a refractive surgery procedure.  The two types of Astigmatic Incisions  are Limbal Relaxing Incisions (LRIs) and  Acurate Incisisions.  Astigmatic Incisions are also referred to as Corneal Relaxing Incisions (CRI's) and are not surprisingly to help reduce vision problems due to:

If you have astigmatism, objects will be blurry and could be doubled both far and/or near depending on whether you have nearsighted or farsighted astigmatism. To learn more about this vision problem, please visit our discussion on Astigmatism.  

Below is a video on Corneal Relaxing Incisions.

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Types of Astigmatic Incisions

The two types of Astigmatic Incisions for refractive surgery are:

  • Arcuate Incisions
  • Limbal Relaxing Incisions 

Arcuate Incisions are referred to as :Astigmatic keratotomy" or "AK" in the ophthalmology.

Who is a Candidate for Astigmatic Incisions?

Corneal Relaxing Incisions and Limbal Relaxing Incisions are  most helpful for people with significant astigmatism who have been corrected for Monovision.  Corneal Relaxing Incisions and Limbal Relaxing Incisions can help improve astigmatism (blurry vision) associated with nearsightedness, farsightedness or presbyopia (reading problems) but will have little to no effect in correcting any  nearsightedness, farsightedness or reading problems (Presbyopia).   Again, Astigmatic Incisions can help with the blurriness but not your other vision problems without another vision correction treatment and can be performed in connection with other vision correction procedures like lens implants and cataract surgery.   

Differences Between Astigmatic Incisions and Limbal Relaxing Incisions  

While both techniques aim to achieve similar goals, there are some differences in their placement and intended effects.

Location of the Incisions

Arcuate incisions. These incisions are made on the cornea, which is the transparent front surface of the eye. Arcuate Incisions are typically created on the steep axis of the cornea to flatten that meridian, thereby reducing astigmatism.

Limbal Relaxing Incisions. LRIs, on the other hand, are made at or near the limbus, which is the border between the cornea and the sclera (the white part of the eye). These incisions are designed to change the shape of the cornea by altering its curvature and reducing astigmatism.

Depth of the Incisions

Arcuate incisions.  These incisions are usually deeper and longer than LRIs, penetrating into the corneal stroma (the middle layer of the cornea).

Limbal Relaxing Incisions . LRIs are typically shallower and shorter than Arcuate Incisions, since they are placed at the limbal region of your eye,  .

Indications Based Upon Astigmatism

The type of incisions made will depend on the level of astigmatism and whether you have mixed astigmatism.

Arcuate incisions.  These incisions are often preferred for patients with moderate to high levels of astigmatism or those with mixed astigmatism (astigmatism with different meridians).

Limbal Relaxing Incisions. LRIs are more commonly used for patients with lower levels of astigmatism or those with regular astigmatism, where the astigmatism is confined to a single axis.

Stability of the Incisions

Arcuate incisions.  These incisions tend to be more stable over time, providing a relatively predictable outcome in terms of astigmatism correction.

Limbal Relaxing Incisions (LRIs): LRIs may exhibit some regression or less predictable outcomes compared to CRIs.

It's important to note that the choice between Arcuate Incisions and Limbal Relaxing Incisions will depend on the specific characteristics of your astigmatism, the shape, thickness and curvature of your cornea, your eye health, the surgeon's expertise, and other factors that may influence the best surgical approach. A refractive surgeon with proven expertise in a wide range of refractive surgery options is better qualified  (a) to properly evaluate vision problems and the health of your eyes health, (b) recommend the best treatments most suited to your eyes and vision goals and (c) successfully perform  those refractive surgery procedures.

Use in Cataract Surgery and Lens Implant Procedures (IOLs)

Arcuate Incisions and Limbal Relaxing Incisions  to reduce astigmatism may be performed in conjunction with any lens implant (IOL) procedure including an IOL implanted in connection with Cataract Surgery.   

Because there are recent advancements in Toric lenses and femtosecond lasers that can help correct Astigmatism for cataract surgery patients, Limbal Relaxing Incisions (LRIs) are less likely to be  used today to correct pre-existing corneal astigmatism.  However, Limbal Relaxing Incisions remain a safe, reliable and predictable option in  correcting pre-existing moderate levels of corneal astigmatism during cataract surgery where other more expensive options (like Toric lenses and lasers) are not available or affordable.

How Are Astigmatic Incisions Performed?

Astigmatic Incisions are made directly on the cornea of your eye with a special diamond scalpel or by using a femtosecond laser (like the one used in All-Laser LASIK or Laser Cataract Surgery). The length and position of these incisions on the cornea will be determined by the amount of astigmatism you have for your eye.

If your surgeon uses a femtosecond laser to make the incision, the surgeon will typically utilize instruments in the laser to measure the thickness of your cornea. Preliminary studies show that these incisions are more precise and effective than diamond blade incisions performed manually.

If your surgeon uses a diamond to make the incision, the surgeon will use instruments to measure the thickness of your cornea and then use a micrometer to set the blade depth in order to properly and accurately make the incisions.

For Limbal Relaxing Incisions, the incisions are placed in the more curved portion of the Cornea in order to reduce the curvature and in that way reduce the Astigmatism.

For Arcuate Incisions), the incisions are made in the more central clear portion of the cornea.

Cataract Surgery

Both Arcuate Incisions  and Limbal Relaxing Incisions may  be performed in connection with cataract surgery to help correct astigmatism.

Arcuate Incisions  and Limbal Relaxing Incisions are typically not covered by medical or other health insurance, so patients selecting one of these vision correction procedures will have to pay an additional charge to the refractive surgeon.

Additional Resources

For more complete and detailed overview on Astigmatic Incisions (aka Corneal Relaxing Incisions or "CRI"), please visit the EyeWiki discussion on Limbal Relaxing Incisions by the AAO (American Academy of Ophthalmology).  This overview discusses the differences between Limbal Relaxing Incisions and Arcuate Incisions including pros and cons of each procedures, risks and complications, as well as pre and post-operative care.  Please note that this article uses the term "Arcuate Keratectomy" and its abbreviation "AK"  so when you see these references to please realize they are referring to what we call "Arcuate Incisions" in our discussions at our site.

How Should I Choose an Eye  Surgeon to Perform Astigmatic Incisions?

Arcuate Incisions  and Limbal Relaxing Incisions  are two refractive surgery procedures that are not performed by every  LASIK surgeon  nor every  cataract surgeons.  Therefore, you may want to find a refractive eye surgeon with proven experience who can properly diagnose your astigmatism and any other vision problems, recommend the best course of treatment, and perform the appropriate procedure.  

How to Find a Highly Qualified and Experienced Surgeon for Limbal Relaxing and Arcuate

Both our Trusted LASIK SurgeonsTM Directory and our Trusted Cataract SurgeonsTM Directory feature highly qualified LASIK and refractive eye surgery experts who have proven experience, are active in the field of refractive surgery, and have been professionally recognized for their research, accomplishments, and contributions to advancing vision correction care.

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