I had a Lasik surgery a week ago, questions

[ericliutexas]

I had a lasik surgery last Thursday. The doctor didnt use wavefront lasik for me. He explained that i am very nearsighted--my right eye was -1000 and left eye -950; if he uses wavefront lasik, more tissue would be removed. So, introlasik was less risky and he did it. Was he correct?

Now, my right eye vision is 20/40 and left eye 20/30. I can not see very far. I also expereince double-images which bother me a lot. What cause double images? When do they disappear? My vision has been relatively stable since the day after my surgery. Do I need an enhancement surgery? If I need it, can the wavefront lasik procedure be applied to my eyes?

Before I had this lasik surgery, another local doctor said I was very nearsighted and not good for LASIK. His explanation was that my cornea would be so flat after surgery that could cause me lose my vision. Therefore, He recommended IOL. But my current doctor, the socalled most expereinced, said that he would recommend lasik because IOL involves more implications. He also added that he would only consider IOL surgery for patients with -1300 or so, but for me (-1000) he recommend Introlasik surgery. What is your opion?

I will greatly appreciate your answer~

Eric

[ericliutexas]

Sorry, I forgot to add the important information:

the thickness of my both eyes is 550.

[LasikExpert]

Your doctor’s logic about conventional Lasik ablation removing less tissue than custom wavefront-guided Lasik ablation is correct and would undoubtedly be an issue with your large refractive error. Additionally, no laser is currently able to provide wavefront-guided Lasik ablation for your high myopia (nearsighted, shortsighted) vision correction. You may want to see FDA Approved Lasik Lasers. An Intralase femtosecond laser created flap can be thinner than a flap with a mechanical microkeratome and has a greater accuracy of realized thickness. See IntraLasik. These are both good reasons to recommend IntraLasik with conventional ablation for a very high myope (nearsighted, shortsighted) patient.

Surface ablation techniques PRK, LASEK, and Epi-Lasik would have a higher probability of corneal haze than Lasik or IntraLasik.

The multiple ghost images are undoubtedly due to an irregularity in the cornea, probably astigmatism either induced or residual. These irregularities may be caused by Lasik induced temporary dry eyes, partial healing that is irregular across the cornea, astigmatism correction that was not complete, or induced astigmatism. The only way to know will be to allow healing to complete and then evaluate your vision.

Lasik induced dry eyes is very common. We have a detailed article on the issue at Lasik Induced Temporary Dry Eye Treatment. Dry eye can cause an irregular cornea and exacerbate astigmatism. Keeping the eyes properly lubricated will promote good healing.

It is reasonable to expect regression back toward the original refractive error when the patient has such a high correction. Regression of 1.00 – 2.00 diopters is likely in your case. Regression is not always even. One spot can regress faster than another and this would cause an irregularity in the cornea. This too should resolve – or at least stabilize – with healing. Regression can normally be resolved with enhancement surgery. Your enhancement surgery can probably be performed with a custom wavefront-guided ablation, however you will need to wait until your eyes have settled down before you will know if wavefront-guided is appropriate or necessary. Your enhancement recommendation may not be Lasik, but may be PRK or LASEK on the Lasik flap. This will depend upon the exact nature of the needed enhancement correction.

Extremely flat corneas can cause noticeable loss of contrast sensitivity or night vision problems, however you have not remarked about either. Different lasers provide different ablation profiles. Some are more prolate than others and the doctor has some adjustment by manipulating ablation size. It sounds like your doctor was able to accommodate your needs in this regard. Flat corneas would normally not cause ghost images.

There are two kinds of intraocular lenses (IOLs) that may have been considered. One is a conventional IOL that is used to replace the natural lens inside the eye. This is called Refractive Lens Exchange (RLE) and would be appropriate only if you are fully presbyopic (over about age 50) and do not present any elevated vitreoretinal concerns. You may want to read Refractive Lens Exchange.

Phakic IOLs (P-IOL) do not require the removal of the natural lens of the eye. P-IOLs are place immediately in front or immediately behind the iris. If your corneas were already a little flat, you may not have had enough anterior chamber depth between the back side of the cornea and the front side of the iris for one type of P-IOL. The other P-IOL may have been appropriate, but much depends upon the exact nature of your refractive error, size of naturally dilated pupils, and the structure within your eyes. You may want to read Phakic Intraocular Lenses

At 10.00 diopters myopic RLE and P-IOLs could be considered, but whether or not they would be recommend depends upon the individual circumstances of the patient and the bias of the surgeon. On this issue I really cannot second-guess the surgeon who actually evaluated your eyes. There is nothing that you have said that would indicate IntraLasik, P-IOLs, or RLE should be excluded. All could have been appropriate alternatives.

[ericliutexas]

Thanks a lot for the reply. I learned much from it. My concern is that my cornea would be too thin or too flat after the enhancement. The thickness of my cornea was 550 before surgery. So, if only 300 is left, would it be a problem?

The second question is: i cannot see ver far. Before my enhancement lasik, is it good to have a new prescription and have a new pair of glasses? or just wait for the enhancement.

Again, thanks!

[LasikExpert]

About a half of century of study has shown that 250 microns of untouched cornea is the minimum required for the cornea of a healthy eye to remain stable. More is always better. Depending upon the exact circumstances, your doctor may recommend PRK for enhancement. This would actually be PRK on the Lasik flap. PRK on the flap would not require removal of tissue under the flap and therefore the thickness of the untouched portion of your cornea would remain the same. You would not want to have enhancement surgery of any kind until about three months postop or until the eye has stabilized (no matter how long that takes).

Because you can expect significant regression, a pair of glasses will undoubtedly be required to give you needed distance vision between now and the time for enhancement surgery. You will want a vendor who will replace the lenses at a very low cost because your vision will be changing rapidly over the next several months. Perhaps this is a service your Lasik surgeon can provide.

[ericliutexas]

will regression occur even after enhancement lasik? How to deal with this? is an additional enhancement normal?

[LasikExpert]

Regression will stablize at some point, usually between 3-6 months. Once stabilized, enhancement surgery may be appropriate.

Regression can occur after enhancement surgery also, but regression does not normally occur on changes of less than about 5.00 diopters. Your enhancement will probably be for no more than 2.00 diopters of refractive change. Regression after enhancement surgery is not likely. Additionally, your surgeon will better understand exactly how your cornea responds to surgery so an enhancement can be a little more accurate.

One enhancement for someone who started at 10.00 diopters myopic (nearsighted, shortsighted) is to be expected. Two enhancements may occur, but is rare. If three enhancements are considered then you probably have other problems that need to be evaluated.

[ericliutexas]

Thanks for the answer~

According to my understanding, the first time Introlasik removes some tissue from cornea; but a PRK enhancement that reopens the flap removes no more tissue, and the thickness of cornea remains same.

Thus my first questions is: If no tissue is removed, how can vision be improved?

My second question is: What are the differences between Introlasik and PRK? Do PRK lasik for enhancement involve using blade? What if the doctor insists on wavefront lasik other than PRK for enhancement? Should I ask help from a different doctor who can do PRK?

My third question is: if the doctor does not create a new flap in the enhancement surgery, how can he exactly tell and reopen the old flap?

I will greatly appreciate your answers.

[LasikExpert]

The key difference between IntraLasik and PRK is where the tissue is removed. IntraLasik ablates the cornea underneath a flap of corneal tissue. PRK ablates the cornea at the surface.

If your enhancement is PRK on the Lasik flap, the Lasik flap will not be lifted. The ablation will be on the surface of the flap. Tissue is removed, but since the tissue is removed on the surface of the flap and there is no additional tissue removed under the flap, the amount of untouched tissue remains the same. It is the untouched tissue that is important for stabilization.

For patients who have a limited amount of untouched tissue, PRK on the Lasik flap can be an appropriate alternative to a traditional Lasik enhancement.

Traditional Lasik enhancement would involve lifting the existing flap, ablating more tissue underneath the flap, then repositioning the flap. No new flap would need to be cut. Even months after surgery the surgeon can manipulate the flap enough to get it to lift. Although you cannot see the flap edge, a surgeon with a microscope can. Traditional Lasik enhancement can be appropriate if there is enough untouched corneal tissue remaining, or if the Lasik flap is especially thin and PRK on the flap is not appropriate.

Wavefront is a method of mapping refractive error and determing where the laser should ablate tissue. A wavefront-guided ablation can normally be done with IntraLasik, PRK, Lasik enhancement, or PRK on Lasik flap enhancement.

[ericliutexas]

As far as I know, my doctor is specialized in Introlasik. I am not sure if he is willing to do PRK. Does PRK require particular equipments different from those for introlasik?

Oilment is required for two weeks. To be honest, I skipped one night. I was so sleepy as to forget to use it. But my sleep was only about 4 hours. Will this mistake cause serious problems?

Also, the hard tip of the oilment tube happened to touch the central part of the surface of my left eye last night. I had my surgery a week ago. Will this possibly cause flap wrinkles?

I used the TEARS of a kind for TWO days. Eventually the doctor helped me find out that it was not preservative free. It is only conventional preservative free--meaning unconventional preservative contained. I switched back to vials immediately. But will this cause problems? Why do preservative TEARS harm?

Although I have tried to protect my eyes as carefully as possible, unexpected things still happened. I feel nervous. I will appreciate your answers!

[LasikExpert]

PRK is a predecessor to Lasik and IntraLasik. It does not require special tools that the average ophthalmologist does not already have. Your doctor will determine what, if any, enhancement procedure is best.

Skipping the ointment for a night should not have caused any problems, but make a note to tell your surgeon on the next appointment.

If you had caused damage to your cornea by touching it with the tip of the ointment tube, you would have noticed immediately. If you didn’t notice any changes then you undoubtedly did not cause damage, however do let your surgeon know at the next appointment.

The preservatives used in eye drops are a mild toxin. They kill the bugs we don’t want there and that allows the drops to last longer. A healing eye is best without extra toxins, so using preservative-free eye drops is always best. If you had caused damage you would already know.

[ericliutexas]

Thank you so much Glenn!

Based on our discussion, I am making a list for next appointment:

For next post-op vist:
1, about the ointment misuse
2, about the TEARS preservative
3, about the one-night skip
4, about eyeglasses discount

For the appointment for enhancement in 3 months:
1, PRK vs Intralasik

[LasikExpert]

Putting together a list of questions and concerns is an excellent idea. All too often in the rush of a busy practice both you and the doctor can get sidetracked. A list helps tremendously.

Also, submit the list to your doctor a day or two before your exam. This allows staff to prepare responses and schedule for any exams that may be needed.

Although you had IntraLasik for your initial surgery, it is highly unlikely that a new flap would be created for enhancement surgery. The existing flap would be lifted, if traditional Lasik enhancement surgery is recommended. If PRK enhancement is recommended, then the flap would not be lifted at all.

[ericliutexas]

Thanks Glenn!

My left eyes is healing well. Although it is not 20/20, maybe 20/30, my vision is not as blurry as last week. My right eye is only about 20/40-50, though. Halo still exists. I hope things will be getting better.


Can cornea of 250 be thick enough to resist the inner pressure of eyes? You said 250 is necessary to assure stability of cornea. I was informed by a friend today that if too much cornea tissue is removed, the inner pressure of the eye will be likely to damage the cornea after surgery. This is especially true for patients with large refractive errors

I was wondering if the pressure increases over time as part of aging process. I am worried because mine vision used to be -9.50, and -10.00, my original cornea was 550. I dont wanna lose vision in my 40s...

[LasikExpert]

I'm glad to hear that your left eye is doing so well. Hopefully the right eye will resolve with healing. Remember that for someone with as much refractiv error as you had, Lasik will not be a "20 Minute Miracle". You will require some time for healing and stabilization.

The condition which concerns you is called keratoectasia, commonly called ectasia. It is the forward bulging of the cornea due to weakness induced by surgery. During the past five decades it has been determined that a healthy eye needs at least 250 microns of corneal tissue untouched to remain stable. More untouched tissue is always better.

Intraocular pressure (IOP) is always greater than the external atmospheric pressure. This is necessary to keep the eye firm and stable. Glaucoma is a naturally occurring disease of the eye that can cause the IOP to increase to the point that damage occurs to the optic nerve. The elevated IOP related to glaucoma is treated with medication and sometimes laser surgery using a laser significantly different from the laser used for Lasik. If you IOP became elevated, ectasia would be the least of your worries. It is the optic nerve that would be at risk. Fortunately glaucoma is easily treated in nearly all cases.

If ectasia occurs, it can present as nothing more than agressive regression of the refractive error - you would become more nearsighted. If the extasia is irregular, you would also have astigmatism. The effects of minor ectasia is commonly resolved with rigid gas permeable (RGP) contact lenses. Catastrophic ectasia may require a corneal transplant.

Fortunately ectasia is quite rare. In two studies with which I am familiar the rate of occurrance was 1 in 3,000 and 1 in 10,000. Because the dynamics Lasik are relatively well understood, surgeons are able to determine in advance if surgery would put the patient at an unacceptable risk of ectasia before surgery.

I highly recommend you discuss your unique situation with your doctor at your next regular visit. The doctor should be able to provide you with the thickness of the untouched portion of your cornea within about 10 microns. My educated guess is that you have about 300 microns of untouched tissue, but your doctor will be able to tell you with accuracy.

Another question to add to your list!