Incision into the cornea
Question: Whats the difference between Photorefractive keratectomy vs Radial Keratotomy?
Answer: Refractive keratoplasty is a generic term, which includes all surgical procedures on the cornea to improve vision by changing the shape, and thus the refractive index, of the corneal surface. Refractive keratoplasties can be broadly subdivided into keratotomies, i.e., corneal incisions; keratectomies, i.e., removal of corneal epithelium; and keratomileusis, i.e., reshaping a stromal layer of the cornea. Additionally ocular implants are now commercially available for the treatment of mild myopia. The following is a description of the most common type of keratoplasties performed as a treatment of myopia, hyperopia, and astigmatism.
Radial keratotomy (RK) Using a high-powered microscope, the physician places microincisions (usually eight or fewer) on the surface of the cornea in a pattern much like the spokes of a wheel. The incisions are very precise in terms of depth, length, and arrangement. The microincisions allow the central cornea to flatten, thus reducing the convexity of the cornea, which produces an improvement in vision.
Photorefractive keratectomy (PRK) uses a computerized laser for corneal reshaping. The excimer laser produces a beam of ultraviolet light in pulses that last only a few billionths of a second. Each pulse removes a microscopic amount of tissue by evaporating it, producing very little heat and usually leaving underlying tissue almost untouched. Overall, the surgery takes approximately 10-20 minutes; however, the use of the laser beam lasts only 15-40 seconds. In patients with myopia, corneal tissue is removed in its center in order to flatten it, while in hyperopia, corneal tissue is removed at its periphery, in order to create corneal steepening. Astigmatism describes a corneal contour which is not perfectly symmetrical, similar to the shape of a back of a spoon. The amount of tissue removal thus varies along different corneal meridians.
Automated lamellar keratoplasty (ALK) This is also referred to as keratomileusis in situ and is used for treating hyperopia. In this procedure a "cap" of corneal tissue is removed and a refractive cut is made with a microkeratome in the stromal bed of the cornea. When the "cap" is positioned back into its original location on top of the eye, microscopic scar tissue is formed, causing the "cap" to bulge out, thus correcting the overly flattened cornea that is associated with hyperopia. The cornea and "cap" adhere to each other, eliminating the need for sutures. Normally, one eye is treated at a time, with about 3 to 4 weeks allowed between each eye surgery. To ease any discomfort, the eye is anesthetized with special drops, and the patient is given a mild sedative to remain relaxed and aware throughout the procedure.
Epikeratophakia or Epikeratoplasty (lamellar keratoplasty) These procedures involve suturing a prelathed donor cornea onto the surface of the recipient's cornea. A microkeratome is used to remove a layer of the patient's cornea and the donor cornea is sutured into the keratectomy bed. This surgery has been proposed as a means of correcting adult and pediatric aphakia, keratoconus (a conical protrusion of the cornea, caused by thinning of the stroma, and resulting in major changes in the refractive power of the eye), and myopia. As a treatment of myopia, this technique has been largely abandoned because of its lack of predictability and poor optical results.
Laser in-situ keratomileusis (LASIK) In this technique the epithelial layer of the cornea is pulled back, creating a flap and the stromal bed of the cornea is reshaped with the laser. Finally, the protective layer is repositioned without sutures and is secure after five minutes of air-drying. The LASIK procedure appears to be gaining in popularity. Removal of tissue from the stromal bed is more precise in comparison to PRK or ALK. Additionally, compared to PRK, LASIK is associated with fewer healing complications and is less painful since the epithelial surface of the cornea remains intact. The location and amount of tissue removed is similar to that described for PRK.
Ocular implants. In April 1999 the FDA approved ocular implants composed of tiny transparent crescents that can be implanted in the periphery of the cornea, resulting in a flattening of the cornea. The ocular implants, called KeraVision Intacs, are designed to treat mild myopia and astigmatism. The implants, although considered permanent, can be removed if complications develop.
Clean Lens Extraction (CLE) Phacoemulsification of the lens with intraocular lens implantation (also called clear lens (CLE) extraction) has been proposed as an alternative to corneal refractive surgery in patients with moderate to severe hyperopia and high myopia. The available clinical evidence consists of case series with small numbers of patients. The outcomes reported indicate a postoperative uncorrected visual acuity ranging from 20/25 to 20/50 in patients with severe hyperopia and 20/40 in eyes with high myopia. There
Question: How much does astigmatic keratotomy(AK) cost? I am considering this procedure for my astigmatisms.I can't find a quote anywhere online and I just want a rough estimate. Has anyone had this done and can tell me how much it cost?
This procedure is done not much anymore. LASIK is the preferred refractive surgical procedure for near-sighted, far-sighted and astigmatism because of its precision and predictability.
Question: Can you get LASIK done if you have had radial keratotomy before? I was extremely near sighted and I had radial keratotomy surgery performed on both eyes in the early 90's. Laser surgery wasn't even FDA approved back then.
As I approached 40, I've lost some of the crispness that I had andI wear glasses some of the time now. I've heard conflicting answers on whether or not I could have LASIK even though I've had RK.
Answer: Depends on how deep the cuts for the RK were. In general, anyone who was myopic enough to require RK had cuts that were deep enough to disallow LASIK now. I suspect what you are experiencing now is presbyopia, and LASIK does not help that anyway.
But be heartened, the first clinical trials for presbyopia repair have been done. The changes of presbyopia are loss of accommodation (ability of the lens to "round up") due to the crystalization and hardening of the fluid comprising the lens. You sound as though you may need reading glasses only. The good news is the changes of presbyopia that are so rapid in your 40s slow down or stop shortly after you turn 50.
Question: Does radial keratotomy vision deteriorate throughout life? I had radial keratotomy in 1985. It was great for a few years. Now my eyes are too flat, and it hurts both near and far vision. Does the flattening ever stop? Can RK eyes have laser surgery without further weakening the structure?
Answer: Most surely, radial keratotomy, has nothing to do with your present state of things:
There are two solid facts: as we do age, the crystaline (the lens behind the pupil,) becomes hadrer and harder, and its difficult for the cuilliary muscles (the ones that accomodate your vision for long and short eyesight), and you will reach some point, in which you will deen eyeglasses, no matter how succesful was you keratotomy
Keratotomy, only corrects the vision defects given by the cornea, however, it does not affect changes with aging, of other structires of the eye (retina, cilliary muscles etc.
Second, the retina also suffers soma changes, that give decreased vision with time.
It will be a matter of determining whether this s proble, of transparency of the fluids behind the cornea (reflexion problems) or the retina has some explaining to do,,,
By the way, have you had your ocular presure checked lately?
That would help a lot.....................
Question: Can radial keratotomy be done again to correct "middle aged eyes" after 15 years? Fifteen years ago I had radial keratotomy on both eyes with an excellent result. I am now 52 and have middle aged eyes. Can the surgery be done again or should I just get reading glasses?
Answer: Of course you can get more refractive surgery. As RK has been shown to be sort of a 'mistake' and no one does it anymore because of the complication rate and the degree it weakens the cornea from ANY trauma. Still they can reshape your cornea with some of the newer laser surgeries. BUT your lens inside your eye grows as you age. The older you get the bigger it gets.
One can actually slice the lens with the slitlamp and have sort of a life journal from the moment your lens formed when you were about an inch long to now. Sort of like the rings of a tree...there's the fire of 1907, remember that? And the changes in the lens as far as growing during our lifetime is the reason we need a new refraction every few years. Once cataract surgery is done, no more change in refraction.
At your age, if you are really concerned about doing surgery and have decided that that's the option you choose, you could get a refractive lensectomy which is cataract surgery but without the foggy lens. THIS we know how to do. Then you'll have distance vision in that eye. There are newer accommodating lenses which may give you distance AND close vision such as the Crystal lens, and the newer Crystal lens.
Another route would be to have a lens insert which is where an incision is made in the cornea and a soft lens placed just in front of the lens inside your eye, just behind the iris. This is a nice way to go. The complication? cataract. The surgery is to remove the implant lens, remove the cataract, place a new lens in the capsule of the old lens, and you are back in business. and with that you've only done one surgery, one risk to that eye.
More RK, well,.......just don't.
Question: Can I enlist in the military with Radial Keratotomy?
Answer: No. History of radial keratotomy is disqualifying. The source below is the medical standard.
Question: Can excessive computer use cause cataracts in people who have had eye surgery? Can excessive computer use cause cataracts in people who have had eye surgery, specifically RADIAL KERATOTOMY?
Answer: No. Cataracts are usually congenital or age related.
Question: Are there any contacts that are good years after refractive surgery? I had keratotomy done on my eyes 13 yrs ago. I'm interested in contacts for my trouble seeing close up and my astigmatism. The trial pair that I tried on today did not work and nothing else was ordered.
Answer: go back and talk it over with your optometrist
Question: can overcorrection by Radial Keratotomy be treated by LASIK? i see things smaller wth right eye . i got operated in 1992 for myopia. the surgery performed was radial keratotomy. and what is the kind of treatment. Can u suggests some names of doctors in INDIA
Answer: It really depends on how many incisions were made during the RK procedure. Our center has treated former RK patients in the past, but we've also had to turn quite a few away. It would be really hard to determine if you would be a Lasik candidate without seeing what your cornea looks like. Best bet would be to find a place to give you a consultation.
Best of luck to you.
Question: Are there contact lens for for post keratotomy(13 ys ago.? The trial pair my dr ordered for me did not work. He sent me home without hope for contacts because of the refractive surgery. Over the yrs, I have developed stigmatism and I also having seeing close up. I was told after the procedure that I may have trouble with this at the age most people do. I didn't count on the stigmatism, too, though. iF i could find some contacts to work, would I be able to order these on my own? Can my prescription be given to me at my request and maybe I could try some contacts on my own ? I don't think he wants to order any others for me to try.
Answer: I dont think he'll right you a perscription if your Samples wouldnt even work. Because if your eye got jacked up it be his fault.
Question: radial keratotomy???how old do u have to be for it?
Answer: Radial Keratotomy (RK) is a procedure that is rarely done anymore, because it tends to be unstable over time (years). Laser vision correction (LVC) is a general term referring to both LASIK and PRK and these procedures are currently more often used than RK. Both LASIK and PRK are typically safer and more accurate than RK.
Most providers consider 18 years of age the minimum age for laser vision correction (LVC). It may be possible for you to have LVC at age 18, depending upon the amount of your refraction (glasses prescription), the stability of your refraction during the last several years, your general medical health, your family history, and other factors. I have treated many patients as young as 18 years old. However, I have also advised many patients in the 18 - 25 year old range that they need to wait a few more years to make sure their eyes are stable before proceeding
Question: Am I the only person in the world this happened to? I wore hard contact lenses before they made the "gas permeable" ones. I wore them form age 13-28. At about age 16, my left eye started bothering me only with the contact in. My opthamologist told me my eyes had almost no tears and to buy some artificial tears. That helped some. So I continued to wear them. Once I was 27 the left one really hurt bad, and another opthamologist said my eyes were extremely dry, but wearing the lenses wouldn't hurt anything. When I was 28, I had to stop wearing them because the left eye was too painful. only with the contact in Then an opthamologist told me a was a perfect candidate for "Radial Keratotomy".(That was before lasik.) Ever since, I've had the pain in my left eye just like the contact lens was in, but I can't take it out because there's no lens in there. After going around the country to over 60 doctors, they all agreed that pain medication was the only option. So I'm on morphine and codeine. It helps some.
Answer: I've never heard of such a thing but, I agree that sucks. It would seem like these doctors would have seen this coming and been able to change treatment somehow. What I don't understand is whether this was a natural thing or something brought on by wearing the contacts ... etc.
I'm sad to hear about that happening to you - good luck.
Question: I need information on cataracts and lens implant surgery. Safety, how long will it last? Where can I locate information this type of surgery and can I locate information about my Doctor doing the surgery as well??
I have tried Mareck.com (only can find Radial keratotomy for myopia.
Answer: This is a sight that I found that may help you.
Question: AF Special Operations vision requirements? Applicants must have normal color vision and the vision of their best eye must be at least 20/70 and their worst eye, 20/100, with each correctable to 20/20 (No Radial Keratotomy).
Im sweating bullets here because my eyesight is worse the the requirements.....where it says correctable to 20/20: does that mean wearing glasses or contacts is ok??
Im 20/20 with my glasses and contacts on.
Answer: You can get a waiver if one eye is 20/70 or better and other no worse than 20/200, or if both eyes are no worse than 20/100.
You can also look into PRK or LASEK (not LASIK). Both of these are now accepted by the AF and will allow you to get a waiver. You will have to wait for about a year after the procedures, however. LASIK is NOT authorized due to military freefall requirements.
Question: Has anyone else ever had pain like this? I wore hard contact lenses from age 13-28. That was before they had "gas permeable" lenses. I had trouble with my left eye from the beginning. My opthamologist told me my eyes were very dry, and to try artificial tears. That helped somewhat. By the time I was 28 I couldn't stand to wear the contacts anymore, because the pain in my left eye felt like there a hot branding iron on my eyeball. When I popped the lens out it was fine. Then a different opthamologist told me a was a pefect candidate for "Radial Keratotomy." That was before "Lasik." Ever since the day I had the RK, I have the same pain in my left eye. After seeing over 60 doctors around the country, they all agreed that drug therapy was the only thing that could help me. So I've been on morphine and codeine for over 20 years. The doctors call it "optic neuralgia." Has anyone ever experienced anything like this? Thank you.
Answer: You need to see your physician to clarify this diagnosis. There are a few things that can cause this. I am not a doctor, but treating it with morphine and codeine seems rather radical to me. In this day and age there should alternative pain relief choices. Have you seen a specialist whose specialty is this type of problem?
Question: Eye pain?? Anyone else in the world? I wore hard contacts from age 13-28. That was before they had "Gas permeable" lenses. My eyes were super dry, but no one seemed to care. Over the years my left eye bothered me. My opthamologist told me to use artificial tears. That helped a little. By age 28, I couldn't wear the lenses anymore. The pain was too extreme. It felt like a hot branding iron on my eyeball. So at least I could pop the contact out. An opthamologist told me I was a perfect candidate for "radial keratotomy." (That was before Lasik.) So I had the RK. Since that day (22 years ago) my left eye hurts just as if I had a contact in. After going to 60 doctors around the country, it was agreed that pain medication was the only thing that would help my "optic neuralgia." So I've been on Morphine and Codeine for years now. The pain is under control. Anyone ever hear of anything similar? Thank you.
I asked this question yesterday, and clicked a "Best Answer" totally by mistake. Sorry about that.
Answer: When RK was done, radial, like the spokes of a wheel, incisions are made in the cornea down to a certain depth. The number of cuts made was determined by the amount of flattening of the cornea the surgeon was attempting to adjust. So the surgery you had, basically cutting the cornea in 8 to 12 radial areas (like a clock), sparing the central cornea, may have caused the surface of your cornea slightly irregular. And these cuts are 95% of the corneal thickness!
It'd be like taking a cake before you put the icing on it, and making cuts, then wanting the areas around the cuts to be perfectly flat. Most of the time it worked. Some of the time, like you, it didn't.
So, your irregular surface causes pain because when your lid slides over the cornea, it causes a slight tearing of the epithelial surface and you have pain. I'm not sure the pain is the type that morphine would be good for, cuz then you are just stoned all the time. Yes the pain is less, but life is less too. Makes everything numb.
Not being a CORNEA specialist, I'm not going to tell you what surgery you'd need to repair this. It would seem that the PRK or the WAVEFRONT types of surgeries now performed for myopia, hyperopia, astigmatism, etc., as it uses the energy of the different types of lasers to basically evaporate tissue, and thus change the shape of the cornea, could be used therapeutically to resurface your cornea(s) so that whey you re-epithelialize that area, it would become spherically smooth. But then you'd be cutting on little slices of corneal pie, and those wounds don't heal so well being inside the corneal structure. So it might be 'dangerous' to attempt this, I'm not sure. Recently in Medscape Medical News the CustomCornea LASIK Algorithms for Myopia were recalled because the results left some eyes irrepairably damaged and contacts nor glasses could correct for it. OUCH!
It seems that when your lid comes crashing down over your corneas, when you blink, if there was some type of surgery that would smooth this out, the lid would then not hit any microscopic edge, and you wouldn't have pain any different than a 'normal' person.
I'd imagine that artificial tears have also been suggested. The one's that would seem to work best, would be those that lubricate...the longer chained molecules, like vaseline vs. baby oil, would be the better choice. Soooooo try celluvisc which does make things a bit blurry, but it'll sure make your eyes feel better. There are other 'thicker' ones too like Refresh PM. Most people BLINK their drops out by squeezing. They become FACE drops, which somehow just don't make the eye any better.
Question: will this fail me at meps (trying to join CCT) ? I was just readying on specialtactics.com (trying to join the USAF CCT) and this is what there telling me.. Have vision of best eye 20/70, worst eye 20/100; correctable to 20/20. (No Radial Keratotomy..)I also just got off the phone with my eye doctors office and they told me that with out glasses I am a 20/200 both eyes, with glasses I am a 20/20.. am I unable join now ?
Answer: Well the website lays out the standards...that being said..what you are asking is like asking..."they say I need two arms but I only have one...will this hinder me?"...well..unless you can magically grow an arm..or in your case...come from 20/200 to 20/70-20/100 at MEPS...yes it will probably disqualify you.
Question: What type of glasses does an optometrist usually recommend for a post RK that uses a computer a lot? What type of glasses does an optometrist usually recommend for a post RK (Radial Keratotomy) that uses a computer a lot? I've noticed problems with my vision in low light conditions. Can it be that I use the computer for too many hours? I have a CRT graphics monitor (LCD was too bright for me) and I currently use some glasses with yellow lenses that are supposed to be for computer and night-driving. I have about 6 incisions per eye.
Please don't just say, "ask your optometrist". I need some informal advice and opinions please.
Answer: To minimise glare effects, you want a reasonably high level of ambient lighting, and the contrast/brilliance on the screen only just high enough to give clear resolution of the letters.
(more is not better at that point)
A tinted glass is not really indicated, but a good anti-reflection coating is.
Unless you are working with copy material, or other reference documents, a single-vision lens set to suit your accommodation and the screen distance is normally the best.
If you are presbyopic, and have differing distance requirements, office varifocals or intermediate/near executive bifocals could be the best set-up.
Here it does really turn on individual considerations and working distances.
Question: What sort of health issues does/did your miniature Schnauzer have? I'm just trying to see what other owners have dealt with along the line of health issues with their miniature Schnauzers. Not Standards or others, but purebred minis.
After 9.5 years, we just lost our sweet girl overnight 11/30-12/1. What's killing me the most is that the vet said she was doing better and would be coming home the next day. Well, she came home, but to be buried.
She was purchased at a pet shop. I KNOW, so the last thing I need is someone finger-wagging and saying how it's "Wrong". Trust me, I KNOW. The only regret I don't have is of her temperament/disposition. Nobody would ever have found a sweeter, better-natured dog. She was playful and active up until 3 days before she died. We as a family are heartbroken and while we knew we did everything we could for her, it still doesn't seem like enough.
What's killing me the most is that we were told how she "perked up" on the IV this time, and had there been even a cautionary "You never know what's going to happen," maybe we could have somewhat mentally prepared ourselves for this. But she died alone, overnight, in a cage at the vet's. I can only hope she didn't know what was happening and that she wasn't afraid. This is what's making me walk the floors at night, and why Xanax is the only reason I'm functioning right now.
We never crate-trained her. From her first night that we brought her home, she slept with us. She meant the world to us and the void in our home now is unspeakable.
She seemed to be prone to just about any and every ailment that this breed is prone to.
The pancreatitis is what started the beginning of the worse, when 2 Christmas Eves ago, she was rushed to the vet and put on an IV. She basically blew her pancreas out and 13 months ago, was diagnosed as a diabetic. She was getting 2 shots a day of Humulin.
She had 2 corneal ulcers (same eye), one requiring a (successful) grid keratotomy.
Just before her death, evidence of the beginning of cataracts (a slight "clouding") had begun in her eyes.
She had several lesser eye infections from time to time.
Chronic ear infections.
Skin allergies, worst at change of seasons.
Figured I'd add due to an answer citing this breed as a popular one...I had my first miniature Schnauzer in 1974. He got hit by a car at the age of 6, and never had any health problems. But I don't want it thought that this is some sort of popularity thing or "fad" breed with me.
@Melly Belly...thank you very much. Big hugs to your little guy and I pray he stays in good health. My girl didn't have cysts so much as, I don't want to call them pimples but they would sometimes come to a head. Other times they -felt- like cysts but would break. And if your guy licks his front paws a lot, that could be a signal of other skin allergies. Hers were more often than not soaked.
@Schnauzer Mom..I don't know how you did it but there's a special place in heaven for people like you. I've had people suggest for me to rescue younger adults, but I can't. I can't deal with more heartbreak on top of this. You are a very special person and thank you for answering my question. I'll keep a good thought for yours and wish them stable health.
Answer: I'm so sorry for your loss. I can't imagine what I would be like without my little guy. I have a 9 year old mini schnauzer and the only real problem he has is that he develops cysts all over his skin. He actually got one surgically removed because it was growing too quickly and now he has 3 more in different places. We're told that they're completely benign and don't really harm him in any way. Other than that..he's had a few gastrointestinal problems because he likes to get into everything and eat it, but nothing genetically I don't think. We also got him at a pet store (which i will never do again) but he's definitely extremely perky.
Question: What to do with my windfall? So I got an extra part time job for the next few months and will be getting a small chunk of change when it is complete. If you read my previous question, I want to take a vacation without my husband because he's a spoilsport. We have always had a "common funds" philosophy regarding our finances, but now he's talking about using the money from my job to get radial keratotomy (eye surgery so he won't need glasses).
Since I told him I don't want to go on vacation (didn't tell him the other part yet), he wants to use the extra money to get his surgery.
Part of me would like to see this happen...but part of me is a little ticked off because he's allocating money I had planned on using for MY vacation on HIS eyes. I know this sounds unfair, since he's always been a good provider, so why do I feel so bitter about it, and how do I get happy about his eyes, instead of focusing on the fact that he's spending the money I made on something that's exclusively for him?
LOL Val, you're a hoot. I'm giving you a thumbs up just for a snappy answer.
Let me add that I've been in charge of our finances for years, and he has always hidden money from me and spent $500 here or there for stuff for himself...but never that amount on anything for me.
Answer: Good grief!
Woman, how many times have YOU used money that HE earned on things that YOU wanted or thought YOU needed?
Newsflash: HE HAS A PHILOSOPHY ON "COMMON FUNDS"!!!!
YOU HAVE A VERY SELFISH PHILOSOPHY.
And to think you a) were going to use this money to take an "escape" from him, b) you lied to him about wanting to go, and c) he's not using the money for a trophy case or a spoiler for the car....but for SURGERY!
He's a spoilsport?
Betcha he wasn't until he met you.
Shame on you very much young lady!
Keratotomy Related Products and News
In this first of a two-part series, Arun C. Gulani, MD, will address the entire corneal aspects of correcting radial keratotomy (RK). The next column will address the lens-based surgeries from phakic to pseudophakic when they are associated with RK ...
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