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Which refractive procedure would you choose?
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Laser vision correction vs. IOL surgery
Case presentation: The patient is a 37-year-old white man who is self-employed as an insurance agent. He is interested in decreasing his dependence on corrective eyewear because he is active with his hobbies of playing golf and watching baseball. The patient currently has no other medical eye complaints.
His ocular, medical and surgical histories are negative. The patient does not wear contact lenses, only glasses to sharpen his vision. The patient’s uncorrected vision is 20/50 in the right eye, 20/70 in the left eye and 20/40 – with both eyes open. Best corrected vision is 20/20 in the right with a refraction of –3.00 +3.25 × 085. Best corrected vision in the left eye is 20/20 with a refraction of –3.00 +375 × 93.
Corneal pachymetry by ultrasound was 520 µm in the right eye and 528 µm in the left eye. Scotopic pupils were 7.5 mm in each in eye, and photopic pupils were 4.5 mm in each eye. Tear breakup time was 10 seconds in each eye. The examination showed a normal anterior segment without any evidence of corneal or lenticular pathology. Funduscopic examination was also normal.
- Which refractive procedure, if any, would you choose: laser vision correction or an IOL implant?
- If you would choose laser vision correction, would you perform surface ablation or LASIK?
- If you would choose a lens procedure, which lens implant would you use?
- If you would choose to hold off on surgery, why?
Orbscan image reading of the patient's left eye.
- Orbscan reading image of the patient’s right eye.
- Wavescan image of the patient’s left eye.
Wavescan image of the patient's right eye.
Approach 1: Jeffrey Whitman, MD
I would perform LASIK if the topography was normal and the patient did not have significant dry eyes; however, even with this correction on the Allegretto Wave Eye-Q excimer laser system (Alcon) and a 110-µm IntraLase (Abbott Medical Optics) flap, the patient would still have well over 300 µm of stromal tissue left.
Another option would be to “debulk” the astigmatism with limbal relaxing incisions (LRIs), wait for refractive stability during the course of a few months and then do LASIK, leaving a rounder optical zone and reducing glare and halo at night with this large scotopic pupil. This would also leave even more of a residual stromal bed.
A third option would be to wait until the patient is in his 40s and perform clear lens extraction with Crystalens AO (Bausch + Lomb) implantation. Assuming that all of the astigmatism is corneal, this would require LRIs at the time of lens surgery and then a touch-up with LASIK or PRK to get the remaining cylinder correction.
Approach 2: Phillip C. Hoopes Sr., MD
This appears to be a fairly straightforward case but lacks the additional data that we would gather in our practice. Two indices are elevated in the left eye Orbscan (Bausch + Lomb). In addition to the Orbscan and ultrasound measurements, we would perform Pentacam imaging (Oculus), TMS-4 analyzer (Tomey) and Tomey ultrasound, and Ocular Response Analyzer (ORA, Reichert) before feeling comfortable with our decision. In our experience, after calibration of all topographic units, the Pentacam readings would show even thinner corneas than the Orbscan. The Tomey has keratoconus-specific detection software and helps rule keratoconus out. The ORA gives valuable information on corneal strength.
The most conservative approach would be to do nothing, followed by having the patient wait another year. After waiting a year, and after a thorough explanation of risks and benefits, and assuming our additional testing showed no changes or problems, if this patient still desires surgery, we would offer PRK as the best procedure. My practice is not a big fan of performing pre-presbyopic clear lens extractions until improvements are made in current multifocal and accommodative lens implants. Furthermore, with this patient’s current astigmatism, current IOL technology would still require PRK touch-up.
Approach 3: Arun C. Gulani, MD
My approach to any refractive case starts with an unbiased evaluation, which then culminates with the one surgical choice that can deliver what I call the entire “vision wish list,” based on that patient’s clinical anatomy, optical status and individual vision goals.
Having reviewed the detailed exam, I feel that this patient’s corneas are normal, with no influence of any contact lenses or evidence of instability. This is regular astigmatism and an excellent opportunity to correct his high keratometry measurements, along with inducing some negative spherical aberration to help with future presbyopia.
In this case of a pre-presbyopic, astigmatic male patient, I would correct the following (vision wish list):
- Astigmatism (mark the axis at the slit lamp)
- Hyperopia (to 0 D or –0.6 D mono)
- Prepare for future presbyopia (correcting the hyperopia, which will induce negative spherical aberration, and additionally aiming for –0.6 D myopia in the nondominant eye based on accommodative reserve measurement and bilateral vision simulation with the patient)
- Remove the least amount of tissue and create a large optical zone (astigmatism correction removes the least amount of tissue and provides a large ablation zone based on laser algorithms)
- Normalize his keratometry (by correcting astigmatism on the cornea, we will flatten his keratometry measurements to a more normal range for better optical quality of vision)
All of these goals can be achieved with one surgery: excimer laser PRK. I will use mitomycin C for 20 seconds, especially at the periphery of his flat axis, with a Weck-Cel sponge (Medtronic Ophthalmics); this is because in some cases of high astigmatism done without MMC, you may see semi-lunar scars in the periphery in a few months, which eventually decrease the laser corrective impact.
Dr. Chu’s response
This patient had very reasonable expectations about his surgical and nonsurgical options. He had tried contact lenses but did not like dealing with them. We had a long discussion about all his various refractive options, focusing on the high degree of astigmatism in each eye. Given his age, we did emphasize the possibility of an IOL-based procedure with a toric IOL implantation. We also talked about waiting for future toric IOL technology to be approved.
We educated the patient about the possibilities of performing laser vision correction, with the downsides of increased glare and halo given the high degree of astigmatism and large pupil size. We also educated the patient about the risks of ectasia. We did emphasize with the patient that his situation is not straightforward and that each of the refractive surgical options has a set of risks that could affect the quality of his vision and the potential long-term health of his eye.
We have encouraged the patient to educate himself and weigh the risks prior to proceeding with surgical options. My initial preference would be for this patient to wait for a higher level of intraocular toric lens correction and/or the possibility of a toric presbyopia-correcting IOL that will be available in the very near future. The patient understands this and is currently considering his options.;
Y. Ralph Chu, MD, can be reached at Chu Vision Institute, 9117 Lyndale Ave. S., Bloomington, MN 55420; 952-835-0965; fax: 952-835-1092; e-mail: yrchu@chuvision.com.
Jeffrey Whitman, MD, can be reached at Key-Whitman Eye Center, 2801 Lemmon Ave., Suite 400, Dallas, TX 75204; 214-754-0000; e-mail: whitman@keywhitman.com.
Phillip C. Hoopes Sr., MD, can be reached at Hoopes Vision, 10011 S. Centennial Parkway, Suite 400, Sandy, UT 84070; 801-568-0200; e-mail: pch@hoopesvision.com.
Arun C. Gulani, MD, can be reached at Gulani Vision Institute, 8075 Gate Parkway W., Suite 102, Jacksonville, FL 32216; 904-296-7393; fax: 904-296-0393; e-mail: gulanivision@gulani.com.
Disclosures: Drs. Chu, Gulani and Hoopes have no direct financial interest in the products discussed in this article, nor are they paid consultants for any companies mentioned. Dr. Whitman has no direct financial interest in the products discussed in this article. He is a paid consultant for Alcon and Bausch + Lomb.