Photorefractive keratectomy (PRK)

Overview 

Photorefractive keratectomy (PRK) is a laser eye surgery that corrects vision by reshaping the cornea, the transparent front layer of the eye, to alter how it bends light. Approved by the FDA in 1996, PRK was initially the preferred laser vision correction procedure until LASIK gained FDA approval in 1999 and became more popular due to its advantages. However, PRK remains a valuable and commonly used treatment, especially in situations where LASIK may not be suitable.

Reasons for undergoing the procedure  

The cornea plays a vital role in focusing light onto the retina, working together with the lens to refract (or bend) light rays so they converge precisely on the retina. When light rays don’t focus correctly, a refractive error occurs. 

Corrective lenses, such as glasses or contacts, help by bending light more than the eyes can naturally, correcting refractive errors. However, some people prefer not to wear corrective lenses, or their vision needs exceed what glasses or contacts can provide. In these cases, vision correction surgeries like PRK (Photorefractive Keratectomy) offer a solution. PRK can reduce dependence on corrective lenses or even eliminate the need for them entirely.

PRK can treat all four major types of refractive errors: 

• Nearsightedness (myopia) 
• Farsightedness (hyperopia) 
• Astigmatism 
• Presbyopia

Risks

Certain individuals should not have PRK because the procedure has a lower chance of success or carries a higher risk of complications. You might not be able to have PRK for the following reasons:  

• Glaucoma.  
• Cataracts.  
• Ocular herpes.  
• External problems affecting the eyes, such as intractable allergies, inflammation of the cornea, etc.  
• Pregnancy (due to changes in the eyes caused by hormones). 

You may experience certain difficulties or adverse effects following PRK. These typically result in adjustments to your vision in the afflicted eye. They may consist of:  

• Haloes surrounding lights.   
• Light-induced glare or ghostly effects.   
• Corneal haze, or cloudiness in the cornea.   
• Vision-impairing corneal scarring. 

A portion of these problems are trivial, transient, and might resolve themselves. Others might require further care to address them. You can learn more about what to anticipate and what will probably be helpful from your eye care doctor. 

Like LASIK, PRK can harm your eyes and impair your vision. Thankfully, that doesn’t happen very often.  

Before the procedure  

Your eye care doctor will assist you with a lot of the PRK preparations. Among them are:  

• An examination of the eyes. Your eyesight and general eye health are examined during the eye exam to make sure PRK is not inappropriate for you.  
• Measurements of eye surfaces. These entail carefully mapping the surface of your eyes, particularly the cornea. 

It’s crucial to know what to anticipate if you want to be happy with the results. Since PRK isn’t a miracle treatment, your eye care doctor will urge you to have reasonable expectations. They will discuss what to anticipate from PRK with you and make sure you realize that it should still enhance your sight even if it doesn’t completely correct it.  

During the procedure  

PRK is an outpatient procedure, allowing you to return home soon after it’s finished. The entire process usually takes between five and 15 minutes. Although you’ll stay awake during the surgery, your eye care doctor will use numbing drops to ensure you feel no pain. 

Once your eyes are numbed, the doctor will remove the epithelium, the outermost layer of the cornea. This layer will naturally grow back over the next few days. The epithelium can be removed with a laser, specialized tools, or a liquid solution. You may feel some pressure on your eye during this step, but it shouldn’t be painful.  

After the epithelium is removed, you’ll be asked to focus on a target light from the laser device. This helps the laser make precise adjustments to the shape of your cornea. Modern lasers often track your eye’s position during the procedure to ensure accuracy.

As you focus on the light, the laser will begin reshaping your cornea. Although the laser beam itself is invisible, you might hear a tapping or clicking sound. The laser works without generating heat, carefully removing corneal tissue to achieve the desired shape, with the epithelium expected to regenerate afterward.  

If you have concerns about keeping your eyes still, let your eye care doctor know. They can pause the laser if necessary, and many modern PRK lasers are equipped with systems that automatically stop if they detect significant eye movement. Minor movements generally won’t affect the procedure.

Once the laser treatment is complete, your specialist may apply medicated drops to your eye and place a bandage contact lens over it. This bandage lens helps protect your eye while the outer corneal layers heal and regenerate.  

After the procedure  

Following the surgery, the following will be administered or prescribed by your eye care doctor:  

• Guidelines for taking care of your eye as it recovers.  
• Pain relief, infection control, and corneal healing medications (mostly in the form of eye drops; some may require refrigeration).  
• Contact lenses bandaged. These frequently resemble throwaway soft contact lenses. You can use them as prescribed by your eye care doctor.

You can leave for home once you’ve received everything from your doctor. When you do return home, bear the following in mind:  

• Go gentle on yourself. Take it easy in the initial days. Don’t engage in physical activity unless your provider gives the all-clear, since it may impede the healing process of your cornea. It’s also a good idea to take a few days off from work or school.  
• Abstain from driving. After PRK, most people will need to refrain from driving for a few days at the very least.  
• Adhere strictly to the care and prescription guidelines. As directed by your doctor, take your medication and wear bandage contact lenses. Your chances of a successful outcome increase if you precisely follow your doctor’s directions.  
• Use sunglasses as advised. Sunglasses protect the cornea from UV radiation damage and scarring. When you walk outside throughout the day, you should follow your eye care doctor’s instructions and do this every time.  

Outcome

PRK recovery occurs in stages. The initial phase takes place in the days right after your procedure, during which you’ll wear a bandage contact lens. This lens helps protect your cornea and aids in the healing of its outer layer.  

Day 1 (surgery day)  

You shouldn’t experience pain until the numbing drops wear off, which typically happens within an hour after your PRK surgery. For the rest of the day, it’s important to rest.

For pain relief, you can consider options such as acetaminophen, Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) like ibuprofen or naproxen, but it’s best to consult your doctor first. They might also recommend specific painkillers to support your recovery.  

Days 2 and 3  

Usually by Day 2 or 3, discomfort and pain levels reach their pinnacle. Most people can use Over-The-Counter (OTC) drugs to control their pain and discomfort. Additional anticipated symptoms may consist of:  

• Photophobia, or sensitivity to light.  
• Foreign object sensation, which is the sensation of having sand or anything similar lodged in the eye.  
• Watering or tearing.  
• Hazed vision.

Days 4 and 5  

By Days 4 or 5, your cornea should be healing well enough to close over. You may start feeling more comfortable with activities like driving and might be eager to stop using your bandage contact lens. However, it’s important to wait for your provider’s approval before discontinuing its use. At this stage, you should notice some improvement in your vision, with further enhancements expected in the coming days.

It’s common to observe a slight ridge or raised area in the center of your cornea after removing the bandage contact lenses around this time. This is a normal part of the healing process and should gradually smooth out over the next six weeks. The ridge forms because the cornea heals from the outer edges inward, and the converging healing tissue can temporarily create a ridge in the center. As healing progresses, your vision will continue to improve.  

After Day 5  

Over the next six weeks, you should see significant improvements in your vision, with the most noticeable changes occurring in the first two weeks. Any pain or discomfort you experience should diminish within a few days.

You will need to continue using the prescribed eye drops for one to four months after PRK. It’s crucial to adhere to the prescribed schedule for these drops, even if your eyes start to feel better, to ensure the best possible results. Avoid strenuous activities for at least a week, unless your doctor provides different instructions.  

Most people fully recover within six weeks, and by six months post-PRK, your vision should stabilize, with minimal further changes expected unless you undergo a follow-up procedure to enhance your vision.

You can generally return to work or school about a week after PRK, possibly sooner. However, consult your eye care doctor before resuming your normal activities, as they may advise you to avoid certain tasks for a while. Be sure to ask about any specific activities to avoid and the duration for which you should steer clear of them.