PRK day 8

It’s now been about 8 days since the surgery. I’ve gone into the office the last two days as well as today, but have been unable to work full days. The fact that 99% of my job includes reading and writing on a computer screen has really sunk in. I can handle enough for a while, but my eyes get too fatigued and the doublevision/ghosting seems to increase over time.

Still, I’m not disappointed at all, as I continue to see improvements every day. I just wish they would start coming faster  I’m driving still, but try to keep my time on the road under ten minutes and within daylight hours. Yesterday I came home at lunch time and took an hour long nap, and my eyes were rejuvenated afterwards and I could work another 4 hours. Today, I skipped this rest period and went to lunch with the guys, but could only make it an hour into work afterwards before the fatigue made me pack up and head home.

As for vision – the right eye is doing better and the ghosting is less pronounced but still blurry to an extent. Large fonts are a must, but they’re starting to clear up to the point that, come Monday, I’m hoping to be able to take the screen size down a notch. Things like this are cause for celebration with my new eyes, as I edge ever closer towards that (fingers crossed) 20/20 vision I’m hoping for.

The left eye is worse and the ghosting/double vision is more significant. Today I realized that with just my left eye open, if I focused through the page I was reading, the two images resolved themselves. This is more of a chore than it’s worth, as I think I overworked my eye muscles doing this from time to time today.

Vision seems to be best when the eyes are thoroughly moistened. I’ll usually use the re-wetting drops and close my eyes for a while, and things are much clearer when I open them back up. For a little while, at least. After several minutes, things start blurring up and separating again.

So in all, I’m happy with the progress so far. There are some blogs that I’ve read of people who take weeks to get to such a point. I have no doubt that in time, the ghosting and double vision will go away and I’ll forget what it was like to ever have this screwy eyesight. The sooner that day comes, the better.

PRK day 4

It's been a total of four days since my PRK surgery. I haven't been able to post any updates because of the insane light sensitivity of my eyes, I could not navigate my PC to save myself. 

The first 2 days were very rough, I'm not gonna lie. There is nothing you can do but sleep. I had some audiobooks and podcasts prepared for the recovery process but they proved very difficult to listen to as I was so focused on my eyes throbbing, there is a constant irritation that is present even when my eyes felt the most soothed from the eyedrops. I was only given enough painkillers for the first day in hindsight I should have kept some more for the follow up day.

Approximately 15 hours after the surgery I had a follow up appointment with the Doctor to check my eyes, he told me they were very inflamed so I'm assuming that means the first day might've been a bit rougher for me than usual.

As of today (Day 4) I have no real discomfort but my vision is very blurry. I've got the huge dark glasses they gave me on and I'm squinting with the page zoomed in to 300% of normal. My eyes get tired after looking at light sources for a while and the eye drops are a relief. Tomorrow morning I will be getting the contacts out I'm very much looking forward to that.

PRK day 0

Greetings friends, I am one hour out from getting PRK eye surgery done. In the interest of science I plan to record the procedure and all or any effects it has on my person be it physical, emotional or mental.

I've seen my Doc, old man Hamish earlier today I was given no type of pre-surgery information other than the usual legal mumbo-jumbo I was required to sign upon agreeing to the preceedure. I am anxious to see the results but from I understand the recovery process for PRK is pretty brutal. I opted PRK over LASIK due to a huge discrepancy in price, the trade off is a longer recovery process.

In PRK they use the same type of laser to reform the eye. The difference is in the method they use to get past the outer corneal layer. Instead of cutting a circular flap they use some type of chemical agent to dissolve then rub away the outer layer. After that is removed the inner cornea can be reshaped by the laser.

In the event of my blinding or death learn from my mistakes: farewell friends

Lasik vs PRK Part 2: Which proceedure is right for you?

PRK and LASIK are the most popular modern methods to correct nearsightedness, farsightedness, and astigmatism, but how do you make the LASIK versus PRK decision?

LASIK is a laser vision correction treatment where nearsightedness, farsightedness, and astigmatism can be corrected by using an Excimer laser to reshape the corneal surface. With LASIK, treatment is performed beneath a very thin flap in the cornea (the cornea is the clear tissue at the front of the eye that light passes through as it enters your eye). PRK is the identical laser vision correction treatment performed directly on the corneal surface (rather than beneath a flap as with LASIK). Both LASIK and PRK treatments provide excellent visual outcomes and freedom from glasses for distance vision for nearly all patients. PRK and LASIK generally provide equivalent visual outcomes. So why would someone choose LASIK versus PRK? Some patients prefer LASIK for its faster healing, and others prefer PRK for its extra safety.

One advantage to LASIK is faster healing times. This is the main reason why LASIK tends to be more popular with patients. With LASIK, the area treated by the Excimer laser is covered by a flap of corneal tissue. Because only the edges of this corneal flap need to heal, usually the healing is quite rapid after the procedure. Patients typically will recover within 24 hours so that they are able to resume driving, reading and computer use within 1 day.

As LASIK requires creation of a flap in the cornea, it does weaken the cornea a little bit more than a PRK procedure does. This is usually not a significant risk, unless the patient has an unusually thin cornea or a corneal shape that may suggest instability.

The main advantage of PRK is its greater relative safety compared to LASIK. LASIK is extremely safe (although no procedure is entirely risk free). Yet as safe as LASIK is, PRK is even safer. Because the laser treatment is performed on the corneal surface with PRK, there is no corneal flap. Without a corneal flap, there are zero risks of flap-related complications. Therefore, PRK has zero risk of a wrinkled flap, displaced flap, incomplete flap, debris under the flap, inflammation under the flap or an imperfect flap. Also, without a corneal flap, more corneal tissue is left intact and the cornea is generally stronger and more stable after the procedure. This also leaves more tissue available for a second treatment or enhancement if it is ever needed. Also, there is some evidence that patients may experience less short-term post-operative dry eye symptoms with PRK compared to LASIK.

The one (and only) disadvantage of PRK is the relatively longer healing time as compared to LASIK, and it’s definitely an important consideration when comparing LASIK versus PRK. With PRK, patients may require an average of 3-4 days before the surface of the eye has healed. During these first 4 days or so, a bandage contact lens is worn to protect the healing corneal surface. Vision is typically better immediately after PRK, but the best vision does require at least 1-2 weeks of healing. PRK patients will usually return to normal activities within 4-5 days.

Every LASIK candidate is generally a candidate for PRK too. Some patients are candidates for PRK only and they may not be LASIK candidates. Examples of patients who may be PRK candidates include patients with thinner corneas, irregular astigmatism, or prior eye surgery. Some patients with certain occupational or sports pursuits may favor PRK if there is a concern about the possibility of future eye trauma. Approximately 15 percent of patients are not suitable for either procedure.

Patients who prefer LASIK will experience a safer procedure when the LASIK corneal flap is made by a laser rather than by a blade.

PRK versus LASIK

There have been a number of studies comparing LASIK to PRK. LASIK is associated with decreased inflammation and quicker recovery, but at the cost of decreased expression of Nerve Growth Factor (NGF) at the surgical bed. PRK, on the other hand, has longer recovery time with more postoperative discomfort and irritation, but rates of ocular dryness are less, as only the epithelium is denuded in this approach. LASIK, on the other hand, involves creation of a corneal flap. The medical literature is not uniform, however, regarding comparative effects on ocular dryness, although the majority of research supports PRK as causing less reduction in tear film. Surgical technique has improved with time, and a more recent study has shown no difference in ocular dryness in LASIK or PRK at 12 months, as compared to pre-operative baseline, although interval assessments at months 1, 3 and 6 did show dryness in both groups. Quantitative changes occurring at the eye surface are more pronounced with LASIK, but more irritation, pain and eyelid sticking are felt with PRK, which could be related to increased denervation with LASIK. A Cochrane Systematic review compared PRK and Lasik; it concludes that LASIK may be better in terms of recovery time and pain.

PRK does not create a permanent flap in the deeper corneal layers, while LASIK involves a mechanical microtome using a metal blade or a femtosecond laser microtome to create a 'flap' out of the outer cornea. As such, the cornea's structural integrity is less altered by PRK. The LASIK process covers the laser treated area with the flap of tissue which is from 100 to 180 micrometres thick. This flap can mute the nuances of the laser ablation, whereas PRK performs the laser ablation at the outer surface of the cornea. The use of the anti-metabolite mitomycin, which is referred as M-LASEK, can minimize the risk of post-operative haze in persons requiring larger PRK corrections, although the medication can worsen the dry eye that occurs after surgery in some patients.Unlike LASIK, PRK does not involve a knife, microtome, or cutting laser, but there may be more pain and slower visual recovery. Unlike LASIK, PRK does not have an increased risk of dislocated corneal flap, which may occur with trauma after LASIK.

PRK Complications

PRK Complications

Some complications that can be temporary or permanent include:

• Dry eyes^[17]
• Recurrent erosions during sleep
• Long healing period
• Pain
• Glare, halos, or starburst aberrations
• Increased ocular straylight
• Under- or over-correction
• Recurrence of myopia
• Corneal haze
• Scarring
• Reduced best corrected visual acuity
• Reduced acuity in low light
• Increased sensitivity

Dry eyes 

As with other forms of refractive surgery, keratoconjunctivitis sicca, colloquially referred to as 'dry eye,' is the most common complication of PRK, and can be permanent. In more advanced cases, recurrent erosions occur during sleeping from adherence of the corneal epithelium to the upper eyelid with rapid eye movement. Adjuvant polyunsaturated fatty acids (PUFAs) with high Omega-3 content before and after surgery improves sicca, possibly due to their anti-inflammatory effects. Foods containing PUFAs include flax and fish oil. Brush PRK to denude the epithelium, instead of alcohol based techniques, also result in quantitatively lower ocular dryness after surgery. The amount of corneal hazing after surgery is also decreased with brush technique. The platelet activating factor LAU-0901 has shown effect in mitigating dry eye in mouse models. Rabbit models have also shown improvement with topical nerve growth factor (NGF) in combination with docosahexaenoic acid (DHA). Mitomycin C worsens post-surgical dry eye.

PRK may be performed on one eye at a time to assess the results of the procedure and ensure adequate vision during the healing process. Activities requiring good binocular vision may have to be suspended between surgeries and during the sometimes extended healing periods.

Halos, starbusts and refractive errors 

PRK can be associated with glare, halos, and starburst aberrations, which can occur with postoperative corneal haze during the healing process. Night halos are seen more often in revisions with small ablation zone size. With more recent developments in laser technology, this is less common after 6 months though symptoms can persist beyond a year in some cases. A dilute concentration of the chemotherapeutic agent, Mitomycin-C, can be applied briefly at the completion of surgery to reduce risk of hazing, although with increased risk of sicca

Predictability of the resulting refractive correction after healing is not totally exact, particularly for those with more severe myopia. This can lead to under/over-correction of the refractive error. In the case of the over-correction, premature presbyopia is a possibility. Experienced surgeons employ a custom-profile algorithm to further enhance predictability in their results.

In 1 to 3% of cases, loss of best corrected visual acuity (BCVA) can result, due to decentered ablative zones or other surgical complications. PRK results in improved BCVA about twice as often as it causes loss. Decentration is becoming less and less of a problem with more modern lasers using sophisticated eye centering and tracking methods.

What is Photorefractive keratectomy or PRK?

Well, where do I start?

Photorefractive keratectomy (PRK) is a laser eye surgery procedures intended to correct a person's vision, reducing dependency on glasses or contact lenses. The first PRK procedure was performed in 1987 by Dr. Theo Seiler, then at the Free University Medical Center in Berlin, Germany. The first LASEK procedure was performed at Massachusetts Eye and Ear Infirmary in 1996 by ophthalmologist, refractive surgeon, Dimitri Azar. The procedure was later popularized by Camellin, who coined the term LASEK for laser epithelial keratomileusis. LASEK and PRK permanently change the shape of the anterior central cornea using an excimer laser to ablate (remove by vaporization) a small amount of tissue from the corneal stroma at the front of the eye, just under the corneal epithelium. The outer layer of the cornea is removed prior to the ablation. A computer system tracks the patient's eye position 60 to 4,000 times per second, depending on the brand of laser used, redirecting laser pulses for precise placement. Most modern lasers will automatically center on the patient's visual axis and will pause if the eye moves out of range and then resume ablating at that point after the patient's eye is re-centered.

The outer layer of the cornea, or epithelium, is a soft, rapidly regrowing layer in contact with the tear film that can completely replace itself from limbal stem cells within a few days with no loss of clarity. The deeper layers of the cornea, as opposed to the outer epithelium, are laid down early in life and have very limited regenerative capacity. The deeper layers, if reshaped by a laser or cut by a microtome, will remain that way permanently with only limited healing or remodelling. With PRK, the corneal epithelium is removed and discarded, allowing the cells to regenerate after the surgery. The procedure is distinct from LASIK (Laser-Assisted in-Situ Keratomileusis), a form of laser eye surgery where a permanent flap is created in the deeper layers of the cornea.

A cool video I found explaining the Basics