Lasik 8 years ago

Post your questions and start your research in this forum if more than three months ago you had any type of surgery to reduce the need for glasses and contacts.

Lasik 8 years ago

Postby ygalver » Sun Jun 04, 2006 3:58 pm

--38 years old today
--Lasik in 1998 in both eyes
--good day vision
--haloes and starbursts at night and low light
--small amount of astigmatism
--glasses sharpen vision but do not eliminate haloes
--considering wavefront
--Should I wait until the FDA approves a laser specifically for correcting night vision problems and perhaps for the doctors to get some more experience? In you website you say that (a) wavefront is only off-label approved and (b) doctors do not really know what causes haloes and starbursts, they think its pupil size but there are cases that contradict this. Also, another patient on the forums said she had wavefront after lasik and she only improved 50%. Seems that if I try it, it may work, but it may not and then what!?

To add to my worries, my doctor warns me of:
--the chance of new cells growing under the flap post-surgery
--the chance of over-correction and presbyopia
--and of course the usual chance of infection and all the other things that may go wrong with surgery

Should I wait?

Thanks
ygalver
 
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Joined: Fri Jun 02, 2006 6:30 pm

Postby LasikExpert » Sun Jun 04, 2006 10:52 pm

Yours is one of the more difficult situations. There is the possibility, even a relatively high probability, that additional surgery will improve your night vision. The problem is that nobody will be able to predict with any sense of certainty what will be the final outcome. There are many patients with similar symptoms who have had Complex Wavefront Enhancement (CWR) with success, but others find only limited improvement or no improvement at all.

Only you will be able to decide if you want to have CWR, but I’ll do my best to provide some ideas and issues for you to discuss with your doctor.

Determining what has caused night vision problems (past tense) is rather easy. Light passing through the undercorrected periphery of the Lasik treatment area is out of focus or otherwise diffused. When the pupils are large enough, this light enters the eye and is “seen”, often presenting as haloes around light sources at night or starbursting.

Past tense is straightforward. Future tense is not so certain.

The difficult part of this issue is determining before surgery who will get night vision problems (future tense). People who have night vision problems tend to have larger pupils, but not everybody with large pupils have night vision problems. Pupil size alone is a poor predictor. There are other issues at play, but exactly what and to what amount is not fully understood. It may be important to read about Lasik and Pupil Size for all the details.

There are some non-surgery techniques for night vision improvement that you did not mention in your posting. These should be investigated.

Rigid Gas Permeable (RGP) contact lenses have a very good history of providing relief from night vision and similar Lasik induced problems. Fitting a post-refractive eye can sometimes be difficult, but there are a few doctors around the country who specialize in custom fitted RGPs that accommodate the reversed geometry of the cornea after refractive surgery.

Before jumping into RGPs, soft contacts may be enough to resolve the problem. Sometimes just a bit of correction or the gentle shaping of the cornea that occurs with contact lenses is enough to resolve the problem.

Orthokeratology (Ortho-K) is a process of using RGP lenses to reshape the cornea while sleeping, During the day the corneas retain some or all of the shape change derived from the RGP lenses. It is possible that you could use RGPs for only a period of time through the day or only at night and get the relief you need.

There are two kinds of eye drops that will cause the pupil size to be reduced. Pilocarpine is a rather strong medicine that will snap down the pupil size rather small and keep it there for a long time. Because of the severity of the action, pilocarpine may have some side effects like headaches that are not desired. Alphagan P is actually a glaucoma medicine that has a side effect of making the pupil smaller, but not as sever as pilocarpine and at a variable amount across the range of pupil size. Alphagan P is almost always preferred over pilocarpine, if it works for the patient. For some, Alphagan P is just not enough.

There are lighting tricks, such as driving with the interior light on, but these are hardly appropriate for the long-term.

When people do have night vision problems, it is almost always able to be traced to an optical ablation zone that is smaller than the size of the naturally dilated pupils. The optical ablation zone is the fully corrected area of the treatment.

It would seem obvious that expanding the optical ablation zone would resolve the issue, but that is not always as easy as it may first appear. Treating just an outer ring of undercorrection is not exactly what the lasers were designed to do. CWR tends to do this better than a conventional ablation, but all currently approved wavefront-guided lasers have a pre-determined optical ablation zone size limitation between 6.0mm and 6.5mm wide. If you pupils are larger than 6.0mm, then CWR may provide some improvement, but not necessarily enough. This is one of the reasons that a recent study determined that for some people traditional ablation with a larger treatment area may be more beneficial than CWR.

Several lasers have created new ablation profiles that do a much better job of correcting the outer edges of the treatment zone. The WaveLight Allegretto is a wavefront-optimized laser that is known for this positive effect. Others do well too, but because the Allegretto is wavefront-optimized and not customized wavefront, it may be able to create a larger optical ablation zone with maximum benefit. This is an issue to discuss with your doctor.

The important objective measurements to be considered are your current prescription, the size of your naturally dilated pupils in a low-light environment, the size of your current optical ablation zone, and which Higher Order Aberrations (HOA) are elevated when your pupils are naturally dilated. CWR tends to work well on Spherical Aberration HOA and coma, but not on trefoil, quatrefoil, and other lower level HOA. I recommend you read about Custom Wavefront Lasik and discuss with your doctor if this is an option.

Cells under the Lasik flap (epithelial ingrowth) is a possibility with any enhancement, but it rather rare and is a somewhat benign complication. It can be resolved successfully in virtually all cases. See Epithelial Ingrowth for details.

Your doctor is wise to warn you about the effects of presbyopia. At 38 you are probably not yet affected, but at some point in your future you will. If you are currently slightly myopic (nearsighted, shortsighted) then this will work to your advantage as presbyopia makes itself known. You should read about Lasik and Presbyopia for the relevant details.

I very highly recommend that after investigating these alternatives, you seek a second opinion before proceeding with any additional surgery. It appears that your doctor is providing appropriate warnings, but the final decision is yours. If multiple doctors all come to the same conclusion, you can be assured your decision is based upon good information.
Glenn Hagele
Volunteer Executive Director
USAEyes

Lasik Info &
Lasik Doctor Certification

I am not a doctor.
LasikExpert
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