Radial keratotomy (RK) was a ground-breaking refractive surgery helping millions achieve clear vision in the ‘80s and ‘90s. But you might wonder if it’s still being done and how effective it is.
In this article, we’ll discuss everything you need to know about RK and how it holds up to modern innovations in refractive surgery.
What is Radial Keratotomy Surgery?
RK was a commonly performed refractive surgery to correct myopia (nearsightedness). Though it was popular during the late 20th century, radial keratotomy surgery is now considered outdated.
RK surgery was developed by Russian eye surgeon Svyatoslav Nikolay Fyodorov in 1974. Now, more advanced and precise refractive surgery options have emerged.
How Did Radial Keratotomy Work?
When performing RK surgery, the surgeon uses a diamond knife to make 4 to 24 incisions in the cornea. These RK incisions flatten the steep central corneal curvature that causes myopia.
Different numbers, types, and patterns of RK incisions may be used. The most common approach involves eight incisions. Deep incisions are necessary to effectively correct the refractive error.
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.
Why is Radial Keratotomy Considered Outdated?
Radial keratotomy has become an outdated procedure, and it’s rarely performed anymore. This is primarily because there are more accurate and stable refractive surgeries available today.
These other types of refractive surgery include:
- Photorefractive keratectomy (PRK)
- Laser in situ keratomileusis (LASIK)
- Small incision lenticule extraction (SMILE)
- Intraocular lens surgery
Additionally, RK has resulted in long-term side effects and complications.
What Makes Newer Surgeries Better?
As mentioned before, there are plenty of modern techniques that are more accurate and stable than RK. For example, LASIK is less invasive and more precise.
Modern tools like femtosecond and excimer lasers are easier to control and lower the risk of complications. LASIK also has a shorter recovery time.
Is Understanding Radial Keratotomy Important?
While it is outdated, it doesn’t mean that understanding RK is wrong or irrelevant. Ophthalmologists should still be familiar with the procedure because many patients have already undergone RK surgery, and some may need treatment for RK complications.
Potential complications include:
- Hyperopic shift. A 10-year follow-up study showed that more than 40% of people who had undergone RK surgery experienced a gradual shift toward farsightedness (hyperopia).
- Diurnal fluctuations. Most patients who undergo RK experience fluctuating vision throughout the day (diurnal fluctuations). This is because a post-RK cornea tends to flatten during sleep and gradually steepen during the day.
- Irregular astigmatism. Astigmatism is a common refractive error that occurs when the cornea has an irregular curvature. An irregular astigmatism can be treated with rigid gas-permeable contact lenses.
People who received RK surgery may also experience other complications, such as a weakened cornea, ocular infections, inflammation, vision loss, and starburst patterns.
What Are the Long-Term Effects of Radial Keratotomy?
Although RK initially provided a solution to myopia, negative side effects have been reported over time. Long-term effects of radial keratotomy include:
- Reduced visual acuity
- Dry eye
- Lower contrast sensitivity
- Glare and halos
- Hazy vision
- Poor night vision
Why Does Radial Keratotomy Shift Vision?
Radial keratotomy involves precise radial incisions made into the cornea, flattening its center to correct myopia. These incisions permanently alter the corneal stroma, initially providing clear vision.
However, the cornea continues to heal and remodel for years, leading to progressive corneal flattening and a hyperopic shift. Over decades, biomechanical changes in the post-RK cornea can increase visual side effects like glare and irregular astigmatism.
Daily fluctuations in vision occur due to corneal hydration changes and slight shifts in intraocular pressure, causing clearer mornings and blurrier evenings.
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