Radial Keratotomy

What is Radial Keratotomy Surgery?

Radial keratotomy (RK) is an eye surgery to correct myopia (nearsightedness). It was developed by Russian eye surgeon Svyatoslav Nikolay Fyodorov in 1974. It was popular in the United States during the 1980s. When it was first introduced, patients were very pleased with the results. However, over time, they became more and more farsighted.

Now, more advanced and precise eye surgery options have emerged. Radial keratotomy is uncommon due to its risks and complications. These other types of refractive surgery include:

• Photorefractive keratectomy (PRK)
• Laser in situ keratomileusis (LASIK)
• Small incision lenticule extraction (SMILE)
• Intraocular lens surgery 

The surgeon uses a diamond knife to make several (4 to 24) incisions in the cornea. These RK incisions help correct refractive error by changing the focusing power of the anterior corneal surface. In other words, the surgical procedure flattens the steep central corneal curvature that patients with myopia have. 

When it was first introduced, RK received recognition for its ability to help correct myopia. Yet, the risks of complications and negative long-term effects outweigh the benefits.

Negative consequences from radial keratotomy include, but not limited to:

• A hyperopic shift or hyperopia (farsightedness)
• Irregular astigmatism 
• Weakened corneas
• Infections and inflammation
• Vision loss
• Fluctuations in vision quality
• Starburst patterns

The cornea is responsible for about 66% of the eye’s refractive power. 

Radial Keratotomy Procedure Steps

The following is a breakdown of the ocular surgery:

1. The eye surgeon performs several incisions in the cornea in a specific pattern. Incision depth reaches around 90% of the corneal thickness.
2. A central “hub” is left untouched in the corner. Radial incisions stem outwards from this element. 
3. Because the number of incisions and hub size affect corneal flattening, the surgeon will determine how many incisions to make and modulate hub size accordingly. 

Eye surgeons typically operate on one eye at a time. They will then wait to monitor the progress and see if vision has improved. These observations of the healing process determine how to proceed with the other eye.

Post-Surgery & Healing

The incisions made during surgery heal slowly and incompletely. The unpredictability of healing is one of the main drawbacks of RK. This is why surgeons will only operate on one eye at a time. They will often wait up to six weeks before operating on the second eye.

Many RK wounds do not heal for years after the surgery. These chronic wounds have a risk of infection the entire time. Studies have also found that patients who receive RK become more and more farsighted throughout their lifetime.

Many patients need additional vision correction years after radial keratotomy.

Pros and Cons of Radial Keratotomy

Radial keratotomy has become an outdated procedure, and its benefits do not outweigh the disadvantages associated with it.

Although it initially helped provide a solution to myopia, negative side effects have occurred.

For example, in a study led by the National Institutes of Health, investigators found that 3% of eyes lost 2 or more lines of best-corrected visual acuity. 

Corneal incisions made during the RK procedure can damage the nerves that affect tear production. This can result in dry eye.

Individuals who underwent the operation also have described experiencing lower contrast sensitivity, halo, haze, glare, poor night vision, and depression.

Lastly, in a 10-year follow-up of RK patients, hyperopic regression (becoming farsighted) occurred post-surgery. 

Additionally, radial keratotomy will not be the first choice listed in an ophthalmology clinic. Better, more precise refractive procedures are available, including LASIK.

Is Radial Keratotomy the Same as LASIK?

Both radial keratotomy and LASIK correct refractive errors. However, there are many differences between the two vision correction procedures. 

LASIK is a less invasive yet more accurate procedure than radial keratotomy. It has a shorter recovery time and less risk of complications. 

LASIK is performed with a laser. This laser removes tissue from the central cornea. Patients can undergo LASIK on both eyes in the same session. This differs from radial keratotomy, which can only be done on one eye in one session. 

An eye surgeon may not prescribe LASIK for individuals who underwent radial keratotomy and now face a deterioration in vision problems. Instead, photorefractive keratectomy may be a more suitable and less invasive procedure in these cases. It is best to consult a surgeon to understand all options available. 

Is Radial Keratotomy Still Performed?

Radial keratotomy is not as common as it was in the 80s and 90s. Other more accurate and stable refractive surgeries are available to treat vision problems. 

However, this does not mean that knowledge of radial keratotomy is irrelevant. Because many individuals have already undergone the procedure, ophthalmologists should be familiar with the procedure and its iterations. Some RK individuals may need visual rehabilitation due to unwanted effects caused by the procedure.  

Similarly, individuals should seek medical advice from their ophthalmologist about this option if highly interested. Radial keratotomy is ideal for those with mild to moderate myopia. 

How Much Does Radial Keratotomy Cost?

Little information about radial keratotomy costs is available because of the procedure’s lack of popularity. 

Also, insurance companies may not provide coverage for this surgery. Other refractive operations can resolve vision issues at a lower price and more efficiently. 

Alternative Surgeries 

The following is a list of alternative surgeries that can treat refractive errors more accurately and with less risk of long-term complications, including:

• Photorefractive keratectomy (PRK). This elective procedure uses a laser to change the cornea’s shape to make the eye bend (refract) light correctly and improve vision.
• Laser in situ keratomileusis (LASIK). This procedure is similar to PRK in that it uses a laser to improve vision. However, it is more invasive because the surgeon creates a corneal flap to reshape the cornea. 
• Small incision lenticule extraction (SMILE). The eye surgeon uses a femtosecond laser to form a round piece of tissue (a lenticule) in the cornea’s inner layer. To remove the lenticule, the surgeon makes a small incision in the cornea. It is comparable to LASIK but with less dry eye and a more stable corneal structure.  
• Intraocular lens surgery. This type of surgery includes the placement of artificial lenses to resolve problems caused by myopia, hyperopia, and astigmatism.