My pre-op journey: f/26, -3 diopters, thin corneas

If you are thinking about having Lasik, IntraLasik, PRK, LASEK, Epi-Lasik, RLE, or P-IOL eye surgery, this is the forum to research your concerns or ask your questions.

My pre-op journey: f/26, -3 diopters, thin corneas

Postby cursorial » Sat Feb 16, 2008 3:39 am

Hi - I love this forum, it has been very helpful, even though I am not in the USA.

By the research I have done, I have found a lot of problems can be avoided by taking extra care selecting procedures, clinics, and surgeons. For the patient, the actual surgery is only a very small part of the process, doing adequate research pre-op and following instructions post-op is much more important. After all, it is your eyes we are talking about so it's very important. I would like to chronicle my pre-op experience here and concerns I have with this experience in the hope it will help others.

Quick stats:
female, 26 years old
Contact lenses are -3.0 left, -3.5 right
EDIT: corneas are 485 and 489 (not 430 like i thought)
Don't know astigmatism.

I had a new-years resolution to get rid of my glasses. They limit me in my favourite activities, contacts are just as bad - eg. one time I went mountain climbing, I woke up in my tent and my contact lens case had frozen. I filled in a form on a web site for a 'free consultation' at a nearby clinic which was the first clinic that came up on my search engine. They rung me up shortly after and booked me in for an assessment.

I turned up keen and excited at the initial assessment. They took me into a small room with flowers, lots of 'thank you' cards from happy clients, and even some framed autographed pictures of local celebrities. They put a 'consent' dvd on. It went for about 15 minutes, had an animation of the lasik, keretome, and Intralase procedures, and ran through some risks and the occurrence rate of those risks. I thought it was a bit glossed over, interspersed with lots of happy smiling people doing things like running along the beach, and didn't really explain the implications of the complications.

Next I met my "co-manager" and she ran some tests. I went through a line-up of about 4 machines that I had to look into. One had red swirls, one a orange dot, one a blue slit that whirled around while I had to keep my eye still in the center, one had an image of a house that kept moving backwards and I was told to keep refocussing on. Then the tester looked at my eyes using an instrument with a tube, held like a gun away from my eye, while I focused in the distance. The tester took my glasses and calculated the prescription of them.

Next I went into a different room and had the usual chart test with different lenses - "which is clearer, A or B". I was asked some questions, such as health history, family health history, if I am pregnant or breast feeding.

After all this, the co-manager told me about my thin corneas, and that I may have to have PRK, or one eye PRK and one Lasik, but she said as PRK is more painful and slower recovery, so she will ask the surgeon to decide what is best. The clinic booked me in for Tuesday next week (8 days away): for a pre-op consultation in the morning, and surgery in the afternoon. They gave me a glossy brochure with what I need to do preparation-wise (no makeup, spray deodorant, get someone to drive me home etc.) and they gave me some brochures and forms for payment plans. The co-manager phoned me the next day and congratulated me because the surgeon said I am eligible for Lasik.

I had read about lasik before going to the assessment, but I did not know what thin corneas meant, or what PRK was. I was under the impression that PRK is an out-of-date procedure that is not done anymore. After doing some research (this site is fantastic and I will link to it from my site and tell my friends, Google books and Google scholar have been invaluable too), I have found that lasik may not be suitable, as my corneas are thin. I know that this puts me at higher risk of certain complications, there is less room for follow-up correction, and I may be better off having PRK - not that the clinic told me this - I found this out myself. So I had second thoughts, and canceled my surgery, but I am still going back to the clinic for a consultation with the surgeon. Judging by the cost they quoted me, I think they want to do Lasik with Intralase to cut the flap (so it is thinner), and with wavefront. They didn't actually tell me what they are doing other than saying I am "eligible for lasik" and that I am booked in for surgery.

Even though I was at the clinic 8 days before surgery, the only forms they have given me is the finance forms, and a glossy brochure about preparation I need - eg. wash hair the night before, get someone to drive me home etc. I didn't get any informed consent form, or any information about the procedure or complications to take home and read. I am wondering when they are planning to give the informed consent form to me - when I am being rolled into the theatre?

I also have concerns that they did not measure my naturally dilated pupils. I had no eye drops put in during assessment, and was not put in a dark room at any time during the assessment. Considering I have thin corneas and thus may have a smaller treatment zone, this is a concern to me.

I will go to the consultation on Tuesday with the surgeon, but I would like to double check a few things here, so it can help me know what to ask him. I will also ask why he recommends Lasik over PRK, based on my layman research I think PRK would be better, especially considering my thin corneas, even though the recovery will be painful. I worry that he prefers lasik because it costs more (more profitable?) and is less work for them with follow-up. Maybe he does heaps of lasiks and not many PRK procedures and prefers lasik because he is more comfortable with it.

Anyway the main questions I have to anyone who knows the answer:

1. Are there ways to measure dilated pupils without using drops or a darkened room?

2. Technology is always changing. I have read some surgeons will not lasik on corneas less than x microns - where x is anything from 450 to 530, although this info may be out of date and based on manual blade. At the assessment they told me at their clinic they go down to pre-op thickness limit of 380 microns (I understand this depends on many other factors and each patient is individually assessed). Does this 380 figure sound like a reasonable minimum for todays technology? I ask because I think the minimum number a clinic gives may give an idea how conservative they are.

3. What would you consider a "large pupil" to be? (under both light and dark conditions)

4. I think intralase can make a flap as thin as 100 microns. Is this figure correct? What is the precision/error of this figure? What risks are increased with a thinner flap?

5. All other factors equal, does PRK allow for a larger treatment area than lasik?

Thanks in advance. I am going to see a few clinics and surgeons. I have already booked in for an assessment at a second clinic. I will share my experiences here.
Last edited by cursorial on Wed Feb 20, 2008 2:47 am, edited 2 times in total.
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Re: My pre-op journey: f/26, -3 diopters, thin corneas

Postby Pappy » Sat Feb 16, 2008 4:44 pm

cursorial wrote:Anyway the main questions I have to anyone who knows the answer:

1. Are there ways to measure dilated pupils without using drops or a darkened room?

2. Technology is always changing. I have read some surgeons will not lasik on corneas less than x microns - where x is anything from 450 to 530, although this info may be out of date and based on manual blade. At the assessment they told me at their clinic they go down to pre-op thickness limit of 380 microns (I understand this depends on many other factors and each patient is individually assessed). Does this 380 figure sound like a reasonable minimum for todays technology? I ask because I think the minimum number a clinic gives may give an idea how conservative they are.

3. What would you consider a "large pupil" to be? (under both light and dark conditions)

4. I think intralase can make a flap as thin as 100 microns. Is this figure correct? What is the precision/error of this figure? What risks are increased with a thinner flap?

5. All other factors equal, does PRK allow for a larger treatment area than lasik?

Thanks in advance. I am going to see a few clinics and surgeons. I have already booked in for an assessment at a second clinic. I will share my experiences here.


1. Yes, they are is a "machine" that can measure it but it is not as accurate as dilation and dim light.

2. The minimum cornea left untouched should be >250microns. I read a few papers about this and basically that thickness of uneffected cornea reduces the chances of ectasia (which is basically a steeping of the cornea due to presure). The more you can leave unaffected the better.

3. Anything greater than 7mm is considered a large pupil. Most ablation zones, specifically lasik are around 6.5mm which may lead to night vision issues.

4. My doc said he regularly does flaps of 90 microns but it can range up to 110. I think this will depend on the particular surgeon. I think this maybe more skill and luck than anything else.

5. Yep, but PRK is really more of a 3 to 6 month recovery versus lasiks "1-week" recovery. You might heal very slowly leaving you with sub optimal vision for 2 weeks or more until you epithelium heals.

You are not in the US, you'd have to check your local laws to see if you have an agency which requires informed consent prior to surgery.
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Postby cursorial » Mon Feb 18, 2008 2:41 am

Thanks Pappy.

I know PRK is more painful and longer recovery, but I am not too busy that I can't take a few weeks off, and I am not afraid of pain so long as I know it is temporary.

I measured my dilated pupils: first I measured my irises with a tape measure in the light (12mm), and then quickly looking at my dilated pupils in the mirror after waking up in the middle of the night, and checking the iris/pupil ratio and making a rough estimate I think they are about 7.5mm. I guess the measurement you really want is what they while driving at night.

So if I do Lasik, my corneal thinness will limit the treatment zone available, and this may be unacceptably less than my dilated pupil size. Wheras with PRK, I can have a deeper ablation depth as a flap will not be required thus allowing a higher larger treatment zone and reduced chance of night vision problems.

I will see what the surgeon says tomorrow, but at this stage I am leaning toward either PRK or just putting up with contacts till something better comes along.
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Postby Pappy » Mon Feb 18, 2008 3:04 am

cursorial wrote:Thanks Pappy.

I know PRK is more painful and longer recovery, but I am not too busy that I can't take a few weeks off, and I am not afraid of pain so long as I know it is temporary.

I measured my dilated pupils: first I measured my irises with a tape measure in the light (12mm), and then quickly looking at my dilated pupils in the mirror after waking up in the middle of the night, and checking the iris/pupil ratio and making a rough estimate I think they are about 7.5mm. I guess the measurement you really want is what they while driving at night.

So if I do Lasik, my corneal thinness will limit the treatment zone available, and this may be unacceptably less than my dilated pupil size. Wheras with PRK, I can have a deeper ablation depth as a flap will not be required thus allowing a higher larger treatment zone and reduced chance of night vision problems.

I will see what the surgeon says tomorrow, but at this stage I am leaning toward either PRK or just putting up with contacts till something better comes along.


Good luck and if you are guessing your dilation zone is 7.5mm make sure they do this measurement low light scenario and maybe a few times. You really want to find the full size, I've been told it's not possible to get too large a measurement. Meaning that if some one measures it at 8mm, that's what it is.

I'm at 4 week post prk (-5.25 each eye) and seeing I'd guess better than 20/20 individually with each eye so my recovery to this point is pretty fast. I don't have "crispness" as of yet on far vision but I expect this will come as the epithelium heals closer to it's final state over the next 4 weeks.

As a personal experience, I was prepared for the pain and the blurry vision. Living it though was a bit different. You find out just how impatient you become. I wish you all the best!

Edit: I should add my pupils are measured at 7mm. I get minor starbursting and currently have a weird "greys" in low light look like they have a glare to them. My doc said my nightvision is going to be affected and slowly return closer to what I had pre-op over the next year. From reading glenns postings here pupil size is not the only determinant in night vision problems but I think most people cosider it to be the major one.
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Postby cursorial » Wed Feb 20, 2008 1:31 am

I will probably write a more detailed response later, but I went to the consultation with the doctor. I must have misheard my corneal thickness, turns out it is 489 and 485, not ~430 like I thought. The doctor does not operate under 450, not 380 like I thought I heard. The corneas are also very normal shape and are healthy, I got a copy of the orbscan. I double-checked the calculations the doctor gave for lasik and they look good compared to the rule-of-thumb measurements on this site. I will have 340microns left after lasik.

He said pupils are 7mm which is normal for my demographic. I noticed that the area where I got my pupils tested initially was lit with red lights (I know about red lights and nightvision from my astronomy days).

He said that he will do a 6.5mm zone, whether PRK or Lasik.

He does 90 micron flaps for all lasik procedures. He says he has never seen thin-flap related astigmatism.

I am going to clinic number 2 in two weeks time.
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Postby Pappy » Wed Feb 20, 2008 3:33 am

You know if he's going to do a blended edge Lasik or PRK?

My pupils are the exact same size(7mm) as is my ablation zone(6.5mm), I'm at 4 weeks post prk and I'd say my night vision is "different", kind of hard to describe as it seems my low light vision is better but my "dark" vision is...different. I'll probably post on it after my next eye exam and I knew that night vision was going to be whacky for at least the first year. It's not bad, it's just different going to take a little adjusting.

In any case I wish you the best of luck, come back and update with what you chose and how it went!
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Postby cursorial » Wed Feb 20, 2008 10:01 am

I don't know what blended edge is. But he really seemed keen on doing lasik rather than PRK. So was the optometrist/co-manager. Which I can understand as it is easier for them (follow-up wise), and they probably perform this on most patients so it is more familiar to them.

There are 4 clinics to choose from in my area, the bigger, more commercial ones (one who have ads on the radio, sponsored in search engines) do intralase, the smaller ones don't. It also seems the better doctors are at the smaller clinics.

The clinic I just went to seemed very busy. I waited 50 minutes for my appointment and the doctor saw maybe 4 patients in that time, also there were others seeing other doctors, and others getting initial testing done. The doctor says he typically does 6-10 operations a day. He must do a lot of consultations too. I think if I decide to do lasik I will go with him because he does thin flaps as standard so he should be good at it. But I am still leaning toward PRK at this stage, although the convenience of lasik is attractive.

Anyway Pappy: about your pupils and nightvision, you are only a month out, so it will probably get better.
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Postby cursorial » Tue Mar 04, 2008 10:41 pm

Clinic number 2:

As the first time, I filled in a contact form on thier web page. Got an info pack in the mail, and the clinic arranged an appointment via email.
The info pack contained a medical history form to fill out. It was pretty comprehensive and I needed to look some things up so I could fill it out.

I went to the clinic, and was the only person there, I asked for the earliest appointment possible. I was taken into a darkened room where I did the blue slit thing where it spins around and you have to keep looking at the middle. Then did a test with red swirls, and the one focussing on a distant image. I noticed the optometrist did not use the pupilometer like the first clinic.
Next I went into the normal room and had my prescription and my current glasses tested. During the whole process, the optometrist talked a lot and explained things well. He says he does the calculations about tissue removal, and the surgeon redoes the testing and calculations on the day of surgery to double-check. The optometrist explained the operation process. This happened while the results of the scans were being printed out.
Then he went through my results and told me my corneas were 502 and 498, and explained what the average corneal thickness, and what the standard deviation is. He said I am a routine case. He also said that I am a candidate for lasik, but there is not much room for further correction. He made his preference for surface procedures clear, and told me he has trouble talking patients into surface procedures because of the recovery time.
He did a Schirmer test, and told me I am the first patient he has had that knew the name of the test 8) The bits of paper felt like they were falling out, it was very hard to keep my eyes still, the paper was in there for about a minute. Then he put fluro drops in to see the tear film, and then looked at my eyes with bright lights. He said that he 'knew I didn't have dry eyes', but needed to quantify it with these tear tests. Next he warned me about the affects of the pupil dilation drops to make sure I was able to make it through the rest of the day, then he popped them in. They took a while to work so it was a good opportunity to talk to him. We got a lot of talking done. Unfortunately I couldn't ask surgeon-specific questions because I don't know which surgeon to choose yet. I asked some of the questions on my list that were applicable. He said he ran a wavefront diagnostic and I have a low level high-order aberations and wavefront guided correction is not necessary. He talked about the Nidek 5000 laser they use, and said it was the "Toyota of lasers" - being reliable, does the job well, not agressively marketted. After all this chatting he looked at my dilated eyes another time. He asked if there were any more questions, and told me to ring them if I think of anything, or if I want to book surgery. I went back to the waiting room which was now busy, one bloke in the room had the eye sheilds on. They sent me off - told me to take it easy with the dilated pupils, and gave me a sample consent form and information sheet.
I walked home 2km (about 1.5 miles i think for y'all Americans :D ) and it was blindingly bright without sunglasses. I should have taken a hat as well, it was sunny and standing in direct sun wearing sunnies I still had to sheild my eyes with my hands. Also close up vision was blurred, but distance was ok - so that's what it is like being far-sighted. I couldn't read the consent form or newspaper, but could watch tv. I watched 'Brokeback Mountain' until I was ready to go to work. Went to work and hilarity pursued over my dilated pupils and sunglass wearing.
And that's about it!
At the moment my emplyment is not secure, while I can afford the surgery easily, for financial security I don't want to do surgery till I know I have a job for at least 6 months or so. So I will wait till that is sorted before I do anything further.
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Postby LasikExpert » Wed Mar 12, 2008 4:26 am

Your refractive error is lower than Pappy started with, and this lower prescription would make the probability of night vision problems less likely.

The surface ablation techniques of PRK, LASEK, or Epi-Lasik all will leave more tissue untouched and give more margin of error. I am admittedly biased toward surface ablations because they eliminate any possibility of a Lasik flap complications (although flap complications are relatively rare). The delayed vision recovery may make PRK impractable for you, but that is your choice.

It looks like you are doing your homework and will make an informed decision.
Glenn Hagele
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I am not a doctor.
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Postby cursorial » Sat May 31, 2008 11:23 pm

I had epi-lasik done on Wednesday, with the epithelium discarded and contact bandage lens (i am day 4 now). The contact is still in and I see the surgeon for the first post-op check tomorrow.

It has been a rough four days, but not as bad as I expected. The boredom was the worst part. I have discovered some interesting radio stations.

I can finally see the computer screen now well enough for it not to be an effort. I will do a write up in the "just had it" section when my vision gets more comfortable.
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