Contact Dr. Stephen Hollis for any questions you may have.

Hollis Nomogram for the Allegretto Laser

The Wavelight Allegretto gives the most accurate corrections of the 7 excimer lasers I have owned.

There is a tendency to overcorrect on the higher minus patients. .

I subtract -0.25 at 5 diopters and -0.25 for each additional diopter up to -14.00.

I was told that we would get overcorrections with astigmatism. I have not found this to be true. I have had several patients with a plano-6.00X some axis. I treated the full Rx and all were 20/20 the next day. I have never been able to correct this error with any other laser.

I do wavefront corrections on all patients that I get a good study and the procedure is indicated. I do it even if the wavefront error is less than 0.3. My 20/15 rate is about 99 % in these cases. There is a tendency to overcorrect myopia even more with wavefront corrections. With wavefront errors:

I subtract -0.25 at 3 dipoters and -0.25 for each additional diopter of error up to -7.00.

In cases that I modified the wavefront prescription because of my refraction, I find I was usually wrong. I would have had a better result when I trust the wavefront. The problem with wavefront corrections is that I cannot get a good study in about 50% of the eligible patients. The Allegretto wavefront device not only measures and corrects wavefront errors but also corrects centration errors. I believe the inability to get a good study is caused by centration errors beyond the capability of the wavefront device to compensate. If Allegretto would allow me to do my job and center every case, I believe we could attain 100% good wavefront studies. I have noticed that when the wavefront device will not align or I cannot export the study, when I do the surgery, centration on that eye is way off. It is the auto centration of the wavefront that is inadequate, not the wavefront study itself. I have achieved a good wavefront study on one eye and not in the other in 20 patients. I did wavefront guided on one eye and standard allegretto lasik on the other.

Not one patient has noticed the difference.

I have done 115,000 refractive cases over the last 30 years. I believe I have done this primarily because I offerred same day surgery. Almost all cases with theAllegretto laser have been done with a dilated pupil. It centers on the larger pupil, and I am re-centering on the optical reflex and not the pupil center anyway. I do tend to use lower light levels to make the patient more comfortable.

Hyperopic procedures tend to undercorrect. I think it is critical to center the procedure on the opical reflex from the microscope, the way we used to center all radial keratotomy procedures. The apparent optical zone is smaller with hyperopia surgery than with myopia. Also, there is a huge difference in how much the optical reflex point varies from the center of the pupil in hyperopes. Hyperopes will often be off one millimeter. Centering hyperopic procedures on the optical center is therefore important in these cases. I make it a habit to recenter all cases, in that I put the blinking green light on the red light. I have seen myopes in which the optical center is 1 mm from the pupil center.

I add an additional +0.25 to the prescription up to 2 diopters of hyperopia, +0.50 up to 4 diopters, and +0.75 up to 6 diopters. This is added to the dilated/cyclopleged prescription on the distance eye. On reoperations I treat the prescription “as is” and I do not add these corrections. I also add these adjustments in mixed astigmatism, eg. +2.00 -3.00X any axis. I change the sphere to +2.50.

My target for monovision is -1.50. To this I add +2.25 to achieve this. Eg. A patient is +1.00 and I want to obtain monovision. I input a +3.25 correction in the laser. There is a slight regression in the near eye, because of the modeling of the epithelium to fill in the low spots. Mitomicin seems to stop haze, but also reduces the modeling, yielding overcorrections with hyperopic PRK. This can yield a 20 to 30 percent overcorrection. I believe the use of computers has moved the near point out to 18 inches on the majority of the population. Ten years ago it was 16 inches.

Be sure to check eye dominance in monovision cases. 1 % of right handed men are left eye dominant, while 50 % of right handed women are left eye dominant. Handedness is useless and misleading when looking for eye dominance. I believe eye dominance is more related to which side of the brain is being used, most of the time, than it is to handedness.

Extended wear single vision contact lens are often used in the office to see how the patient will tolerate monovision. If the astigmatism is over 0.75, I find toric contacts cannot approximate the vision for monovision and are not helpful. I find the patients tell me how well they are handling monovision within an hour of putting the contacts on them. With contacts, cataract surgery, RK, ALK, CK and lasik, I have attempted monovision 40,000 times over the last 30 years. I attempted monovision in most of the 20,000 cataracts that I did.

In my experience, 99 % of patients will adapt to monovision, if it is +/-0. 25 in sphere and cylinder for distance, and -1.25 to -1.75 for near.

Age has long been known to influnce the effect with refractive surgery. I have been impressed that the flying spot of the Allegretto does not show a lot of change with age I used to subtract 1/3 of the error at 45 and ½ of the error at age 60 with RK.

With the Nidek laser, I subtracted 10% at age 45 and 20% at age 60. This occurred abruptly at ages 45 and 60 and was not gradual as shown in many nomograms. I read an article in the Russian literature that said the fibrils in the cornea realign themselves at 45 and 60 years of age.

With the Allegretto I reduce the attempted correction in myopes 5% at age 45 to 59, and 10% at age 60 and above. I use no age adjustments in hyperopes.

I used to see bad epithelial breaks in older patients. I have eliminated this by pre-treating the cornea with oxygen for 10 minutes prior to the procedure in everyone over 35 years old. I use a home health oxygen generator combined with goggles made by Medlogics to apply the oxygen.

I do dilated/cycloplegic refractions on all new and post-operative patients. Most patients are wearing glasses that have too much minus. Most hyperopes will reveal more hyperopia when dilated. Patients after myopia surgery will come in at 3 months with perfect vision, but the dilated exam may reveal a +1.50 Rx. If I did not dilate/cycloplege my postoperative patients I would not have caught this overcorrection. It is rare for me to see my patients back 10 years later after being dismissed from lasik. Ninety percent of my patients are dismissed on their 3 month visit to see me, and returned to their primary eye doctor.

I have read that some doctors operate on the undilated/noncyclopleged hyperopic examination. Since we undercorrect no matter what we do, that makes no sense. I have had a few patients return from hyperopic surgery with blurred vision and -1.50 Rx. I dilated them and they were 20/20 showing that this was residual accomodation. I put them in a -0.75 extended wear contact, and brought them back in 3 weeks and then eliminated the contacts. I have re-operated on no patients that ended up minus after the first hyperopic procedure.

I find a tendency to leave myopic patients without enough minus for monovision in their near eye. If their prescription on their near eye is -3.50-1.00X180, I would correct

-2.00 -1.50X180. There near eye would end up -1.00, which is not good enough for near. Now I target them for -2.00 and it ends up -1.50. The Allegretto laser is right on in astigmatism and myopia up to 5 diopters. I do not understand why I am getting over corrections when I attempt monovision in myopes. My answer is that it is harder to induce myopia than it is to treat myopia. It seems there is a built in mechanism that modifies the result when the targeted distance vision is not 20/20 in the eye targeted to be the near eye..

I use the 6.5 OZ up until the patients pupils excedes a 7 OZ. Glare problems at night are extremely rare with the Allegretto. I have used the 7 OZ setting on about 20 patients and the 8 OZ on about 5 patients. The 7 and the 8 OZ tend to give undercorrections. I add 10 percent to the corrections with the 7 OZ and add 20 percent with the 8 OZ. In some patients with a thin cornea and high myopic error I have switched to a 6 OZ to save tissue. The “sweet spot” with the Allegretto laser seems to be set for an OZ of 6.5 mm.

I find I get overcorrections when I use a 6 mm OZ,. so therefore I back up 10 percent on the desired correction in myopes..

Cataract surgeons lose one eye in a thousand to infection or hemorrhage. I was pleased that we only lose 1 to 4 lines of vision in one eye per thousand lasik procedures. Why does this occur. I believe there are 2 reasons:

1) decentrations of procedures, caused by not centering on the optical reflex on the cornea. This is much more of a problem in hyperopes.

2) After using the Pentacam for 2 years now, there is no such thing as a normal cornea. All corneas are “lumpy bumpy” and the patients are choosing the best area to look through and ignoring the worse one. When we do standard lasik, we are inducing more or “different” irregularity, or at least compounding what is there. The patient does not find the new optimum window to look through and experiences a loss of vision. Therefore, topography guided lasik has to be approved in America. Lasik surgeons are being asked to do our job with our hands tied behind us, until we get topograpy guided lasik approved. The Pentacam type topographer is far more accurante than standard topography.

Someone came up with the theory that flying spot lasers have to have auto-fixation, while large beam lasers do not. I do not agree, but I like the convenience of auto-fixation. I have done 15 patients who would not fixate after the flap was made, or they had very irregular pupils, that would give erroneous fixation. I did all these patients without the auto-fixation and the results were good and none required re-operation. This is example of someone’s good idea becoming a law, but it is incorrect..

I apply a fluoroqinolone antibiotic to the bed just before applying the laser and then dry it with a weck cell. This gives a fluorescence which has the following benefits:

1) I can see the treatments.

2) This is good for teaching and for the families observing.

3) I can see if I am hitting the hinge, or outside of the bed.

4) If one area glows brighter or gets a variegated appearance, it needs to be dried.

Iquiix is a more concentrated medication and it glows the brightest.

The mixed astigmatism feature of the Allegretto is remarkable. Most lasers will flatten the cornea to correct the astigmatism and then steepen the cornea for the hyperopis. The Allegretto will steepen both. The results are incredible. Sometimes the laser is steepening and sometimes flattening the meridian for the astigmatism based on the prescription.

About 6 events have occurred in my practice to improve the results with the Allegretto.

1) I do my own refractions.

2) I do cycloplegic refractions on all patients on all visits (midriacyl 1 drop 20 minutes before refraction). The end points are much crisper. Of course I find more hyperopia, which decreases undercorrections.

3) The Medlogics microkeratome is giving me consistent 80 to 100 micron flaps with a 9.5 mm diameter. This improved the hyperopic corrections.

4) Incorporating the Pentacam was confusing for a year, and then it really added to my understanding of what was happening with lasik.

5) Recentering all procedures on the optical reflex and not the center of the pupil, drastically improved the results with hyperopia. I recenter every eye.

6) Applying pre-op oxygen for 10 minutes to the cornea in all patients over 35 years old has eliminated epithelial breaks on the flap.

I have seen 4 infections in the last 16,000 eyes, all related to epithelial breaks or PRK.

All were on Zymar when they developed the infection. All got better overnight with Azasite, and were completely healed at 7days. Since then, I use Azasite along with Zymar in all PRK’s or with epithelial breaks (whick I do not see anymore). I have seen no corneal ulcers since starting this regimen. I have eliminated the Acular or Xybrom, since they are not necessary with lasik, and in it’s place added Azasite along with the Zymar in all cases.

One of the most important changes in my practice has been giving Imitrex 100 mg orally just prior to PRK. I have completely eliminated narcotics from my practice with this change. Any of the similar drugs also works. Most of these medications are now given with a nasal spray, so this is a new use for the pills.

There is some controversy over the doing of refractive surgery on lazy eyes. I have accomplished this on over 200 patients successfully. If I can improve the vision in the lazy eye by 3 or more lines of vision, it seems logical to do it. I have seen patients with refractive amblyopia improve 2 lines of best corrected vision, a year after their full surgical correction. The main risk, is that if the eyes do not align, bacause of the reduced vision in one eye, we may induce diploplia. I have found this to rarely be a problem, but it is important to examine the patient for phoria/tropia errors prior to the prodedure.

Even if the patient does have diplopia after refractove surgery, it tends to improve with

time.

The main problem I have found with the Allegretto laser is figure 8 haze in patients using the 6.5 mm OZ in PRK. The OZ for the astigmatism correction is 8 mm. Changing to a 6 mm OZ for PRK, gives an astigmatism OZ of 6.5 mm. The large OZ for astigmatism works well with lasik, but can cause a figure 8 shaped haze with PRK, that is very difficult to repair. This is because of the large excavation of corneal tissue in a figure 8 pattern. At first I did not like the Allegretto for PRK, until I discovered the success of using the smaller OZ. If the patient has a large pupil, this could be a problem with doing PRK.

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