PROCEDURES

Should I have LASIK surgery on Both Eyes at the Same Time?
(Or in, medical terms Bilateral Simultaneous LASIK?)

By James J. Salz, MD

I have personally never performed bilateral simultaneous RK, AK, PRK, LASIK, clear lens extraction, or cataract surgery because I am convinced it is not in the patient’s best medical interest to do so. Of all these procedures, I would agree that the strongest case for bilateral simultaneous surgery can be made for LASIK. Why then do I advise my patients not to have any refractive surgery procedure on both eyes at the same time? It really comes down to a personal philosophy to always place the patient’s best medical interest before issues of patient and surgeon convenience, financial considerations for patients, surgeons and laser centers, and building refractive surgery volume.

I will concede that if the surgery and post operative course are without complications and side effects, bilateral simultaneous LASIK and even PRK and RK are very convenient for the patient since both eyes heal together, time away from work is minimized, and the necessity of temporarily wearing a contact lens in one eye is eliminated. The surgeon and the laser center also benefit financially since it takes just a few additional minutes to perform the surgery on the second eye once everything is set but the fees are usually doubled (at times with a modest discount for the second eye) and the follow-up visits are effectively cut in half. Because the vast majority of patients will do quite well, this is a very effective practice builder since all these satisfied (WOW) patients will go out and sing the praises of the surgeon and the center.

So why not do it? Let’s look at that little word if at the beginning of the previous paragraph. What if the surgery, the postoperative course and side effects present problems. I can separate my arguments against simultaneous surgery into three potential disadvantages for the patient and one potential major disadvantage for the surgeon. Potential disadvantages for the patient are: the risk of serious complications leading to significant visual loss; the possibility of an unpredictable outcome; and potential dissatisfaction with the side effects of the surgery. For me to recommend simultaneous surgery, I have to be certain there will not be a vision threatening complication, that the outcome will be predictable, and if the outcome is predictable that the patient will be satisfied with the quality of their vision in the real world. Since I can never be certain of any of these three conditions, I cannot in good conscience recommend this to my patients. If our primary responsibility as physicians is to always do what is in the patient’s best medical interest, it’s hard to justify elective, simultaneous surgery. The disadvantage to the surgeon involves the potential magnitude of a potential malpractice claim in the event of significant bilateral loss of vision. Let’s first explore the potential disadvantages to the patient.

Risk of serious bilateral loss of vision

The risk of infection following LASIK appears to be very low, despite the fact that it is not truly a completely sterile technique like cataract surgery because it is not performed in a hospital operating room with more stringent standards of sterile technique and the entire microkeratome cannot be completely sterilized because of the motor and cord. Although the risk of infection appears to be quite low, the presence of an infection under the LASIK flap presents unique challenges in management and would be quite likely to lead to significant scarring and loss of vision. Should an infection occur in one eye, it will quite likely occur in the other eye since the same microkeratome and blade are used in both eyes. Even if this risk is only 1 in 5,000, given the potential for the infection to occur in both eyes and the potential for serious scarring at the interface, even if the infection is adequately controlled, I don’t think the risk is justified. What’s the hurry?

Although not as potentially serious as an infection, Bobby Maddox and others have reported numerous cases of bilateral interface haze appearing within the first two or three postoperative days. At the recent ISRS meeting is San Francisco, Dr. Lawrence Spivak from Denver, Colorado described interface haze in 22 eyes following LASIK. Although one or two were unilateral cases, most had bilateral simultaneous surgery. On the first postoperative day, the haze was mild to moderate, gradually increasing over the next several days, with clearing over the next few weeks following treatment with topical corticosteroids. The decrease in best corrected visual acuity varied from 20/25 to 20/200 during the acute phase with recovery to 20/20 in all but one eye which was overcorrected to +2.00 D with 20/30 visual acuity. Interestingly, this case was a re-operation where the original flap was lifted without the use of the microkeratome. Since the etiology and exact incidence of this unusual but perplexing complication is unknown, it would seem only prudent not to put both eyes at risk. What’s the hurry?

Just this past year I have examined 3 patients for second
opinions that had bilateral complications following LASIK. One was an
ophthalmologist, one a dentist and one a businessman. All three missed
several weeks of work because of their bilateral complications, primarily
related to the inflammation under the flap, called diffuse lamellar
keratititis. Had only one eye been operated on, they would have been able to
function with their contact lens in the unoperated eye while the eye with the
complication gradually improved with treatment.

In addition to the risk of bilateral simultaneous infection and bilateral interface haze, an even more serious concern is the possibility of vision threatening retinal complications. Certainly the possibility of vitreous hemorrhage , central retinal artery occlusion, retinal hemorrhage and retinal detachment all exist, and some of these complications have now been documented. At the International Society of Refractive Surgery Symposium, October 25, 1997 in San Francisco, Dr. Jose Luna from Argentina reported non-refractive complications after 700 bilateral simultaneous LASIK cases. One patient (approximately -12 D pre-op) who underwent bilateral simultaneous LASIK was found to have bilateral sub-macular hemorrhages and best corrected visual acuity of 20/400 on the first post-operative day. Six months later best spectacle corrected visual acuity was 20/60 in each eye. Dr. Luna also reported a post-operative retinal detachment in one eye and another case with bilateral iatrogenic keratoconus following the inadvertent use of a 360 micron thickness plate.

At the annual meeting of the Argentine Society of Ophthalmology last summer, Dr. Ricardo Dodds reported bilateral simultaneous retinal detachments on the first post-operative day following bilateral LASIK and another case with extension of lacquer cracks into the macula. Try to tell these unfortunate patients with the retinal complications, some facing permanent loss of vision in both eyes, that these complications are rare. For them, the incidence is 100%. These problems could have been avoided with even a delay of one day between eyes.

In a recent article in Ophthalmology Times the headline stated "Same-time LASIK safe, study says." This was based on a study at Emory comparing the results of a prospective randomized study on 709 patients, 378 had bilateral simultaneous LASIK and 331 had sequential LASIK two weeks apart. Fortunately, there was no significant difference in intraoperative complications or in the number of patients who lost two or more lines of best spectacle corrected visual acuity. In discussing the study, Dr. George Waring stated: "The risk for intraoperative complications is the same, because if we are operating on a patient where we intend to do bilateral surgery and have a complication in the first eye, we don’t do the second eye, so that safety is built in."

In fact, not having an intraoperative complication in the first eye is certainly no guarantee that the patient will not end up with a bilateral post-operative complication. None of the procedures leading to serious retinal complications in the patients from Argentina and none of the patients with bilateral interface haze had complications at the time of surgery. I think it is misleading to state that the Emory study showed that "same time LASIK is safe, "because the numbers are too small. Simply doubling the number of cases as was reported in the study in Argentina, resulted in serious bilateral complications.

If I performed 378 bilateral simultaneous cataract operations without a serious complication and compared them to a series of 378 unilateral cataract operations, I could state that my study showed that bilateral simultaneous cataract surgery is safe. Does that really mean we should all start doing it? At least cataract surgery is being performed on eyes with true pathology and already decreased vision. The majority of these LASIK eyes have 20/20 best corrected vision. Why risk permanent bilateral visual loss no matter how low the risk. Refractive surgery, being performed on essentially normal eyes, should surely be held to a higher standard. What’s the hurry?

Predictability of outcome

Although there is certainly less influence in the healing process by surface mediators in LASIK compared to PRK, the possibility of an unexpected result still exists. The algorithms are still being modified for the various lasers and even now the role of factors such as patient age, amount of myopia and room humidity in predicting the final refractive outcome in LASIK are still being debated among the experts. Individual variations in the cornea’s response to the excimer laser still occur, and by delaying the surgery at least five to seven days between eyes permits the surgeon to modify the surgical plan in the second eye based on the results in the first eye. This can at least theoretically lead to a better outcome in the second eye and possibly eliminate the need for a re-operation in the second eye.

Although many LASIK surgeons discuss the ease of lifting the flap and doing more surgery, this is not as benign as it sounds, and many of the speakers at the recent ISRS symposium discussed the increased risk of complications such as epithelial ingrowth following secondary flap manipulations. If sequential surgery can possibly improve the outcome in the second eye because the amount of correction can be adjusted after seeing the result in the first eye, then the incidence of re-operations in the second eye can be reduced, thus reducing the risk of complications. What’s the hurry?

Patient satisfaction with the procedure

There is certainly more to the final result of any refractive surgery procedure than the uncorrected visual acuity and best spectacle corrected visual acuity. Both of these objective measurements can be excellent in a patient who is nonetheless quite unhappy with some aspect of their postoperative vision. We have all had patients who have had a refractive surgery procedure with an excellent outcome in terms of visual acuity but are unhappy about some aspect of their vision in the real world. It can be halos or glare at night, difficulty with night vision due to some loss of contrast sensitivity, or vision that is simply "not as good as it is with my contact lens in the other eye." Of course I have heard bilateral LASIK advocates seriously state that this is one reason to do the two eyes together, so that the patient can’t compare the LASIK eye with the contact lens eye!

This perceived difference in the quality of their vision can be a major concern for some patients, and it is certainly in their best interest to let them fully appreciate the quality of their new vision in the real world before they commit to having the surgery in the second eye. This is particularly true in patients with relatively low refractive errors who have the option of either wearing glasses or contact lenses in the untreated eye. With all the advances in contact lens technology, even the higher myopes can usually be fit with a contact lens in the second eye while they evaluate the quality of their vision in the treated eye. If they are not completely satisfied, they have the option of continuing in the contact lens until new developments such as larger ablation zones, flying spot lasers with customized potentially smoother ablations or phakic intraocular lenses become available. Once again, what’s the hurry?