CASE HISTORY
A 58-year-old white male with no history of medical problems presented with an interest in undergoing LASIK in order to become free of his bifocals. He reported having abandoned his contact lenses 10 years earlier “because they were too much of a hassle.” Although he described no particularly adverse visual symptoms, upon questioning, the patient admitted that he did not like driving at night because he experienced “halos and bright lights.” He acknowledged that he would require reading glasses postoperatively.
The preoperative examination revealed that the patient had 2.5-mm photopic pupils and dark brown irides that dilated to 4.5 mm in the dark. He wore +3.50-D spherical bifocals with an add of +1.75 D. His bilateral manifest refraction was +2.75 D with an add of +2.25 D. The patient's average keratometry reading was +46.50 D OU. His BSCVA was 20/20 OU. Upon questioning, the patient recalled that his optometrist had changed his glasses' prescription slightly during the previous year. Biomicroscopy revealed normal corneas without guttata, a lustrous tear film, and a rating of 0.5 to 1.0 on the nuclear sclerosis and opalescence sections of the LOCS scale (Figure 1). His lenticular cortex could have been interpreted as less than totally clear but was basically unremarkable, as was the capsule. The patient's fundus examination was also normal.
HOW WOULD YOU PROCEED?1. Is this patient a good candidate for LASIK?
2. If not, should he be considered for another refractive procedure now or in the future?
3. What are the relative risks and advantages of an intraocular procedure (either a phakic or replacement lens implant versus a keratorefractive procedure such as LASIK or PRK)?
SURGICAL COURSE
I recognized that this patient was undergoing sclerosis (and presumably secondary swelling) of his natural lenses, which accounted for the small myopic shift in the patient's spectacle prescription evidenced by his history and the refraction at examination. Nevertheless, the patient's BSCVA remained 20/20 OU under examination-room conditions. Although his natural lenses did not have the crystalline clarity of a 20-year-old, they were not much different from what one might encounter in a typical 58-year-old.
I weighed the options: (1) Advising the patient that there might be “early cataracts” forming and to wait until they impaired vision enough to merit cataract surgery with IOL implantation; (2) performing hyperopic LASIK or LASEK; (3) electing to use a corneal, midperiphery, collagen-shrinking technology such as hyperopic thermokeratoplasty; or (4) performing a refractive lensectomy with either a monofocal or multifocal IOL.
Although the most aggressive choice was a refractive lensectomy without waiting for further progression of the developing cataract, I could reasonably expect that this procedure would achieve a UCVA close to distance emmetropia. If not, IOL exchange would be an alternative. I realized that the patient would, in all likelihood, eventually require an Nd:YAG capsulotomy, but this procedure has not been associated with a significant degree of pathology in reliable studies.
The patient underwent an uncomplicated lensectomy in each eye. I used the Holladay II formula in order to leave the patient plano after surgery and the implantation of two single-vision IOLs. In each eye, I created a clear corneal incision at the far temporal limbus with a limbal relaxing incision at 90º. The procedures occurred
1 month apart and were performed in the office-based ASC department. The patient paid for his surgery out-of-pocket.OUTCOME
The patient's UCVA 3 months postoperatively was 20/25+1 OD with a manifest refraction of +0.75 -1.00 X 90º = 20/16 and 20/32+3 OS with a manifest refraction of -0.50 -0.75 X 85º = 20/16. He was enthusiastic about his distance vision; he had regained the ability to drive, watch television and films, and attend social functions without spectacle correction. The patient was only moderately pleased with his vision at arm's length and required pharmacy-bought magnifiers for reading and computer use. He underwent bilateral Nd:YAG laser capsulotomies 6 months postoperatively.
DISCUSSION
Deferring lensectomy until it was justified by the degree of cataract-induced opacity would undoubtedly have been the most conservative approach to this case. After 7 years, the patient would have become eligible for Medicare coverage of the procedure, which he might well have appreciated. A surgeon expert at the use of third-generation IOL formulas and no-contact axial length measurement would probably be able to achieve a visual result close to 20/20 bilaterally at distance. I did not select this option because it would have ignored the patient's stated goal, which was the immediate optimization of uncorrected distance vision.
That desire prompted the patient's original request for LASIK (or PRK/LASEK), and certainly current excimer technology could have corrected his degree of hyperopia. In his case, there did not appear to be a danger of overly steepening the cornea, and the patient would likely have easily tolerated a residual error that was slightly plus or minus. I decided against performing LASIK in this patient because of the strong likelihood that he would experience progressive nuclear sclerosis. This development would have produced a further myopic shift in his near-to-intermediate future that would probably have rendered him sufficiently myopic to necessitate spectacle-wear for distance. Declining visual acuity due to decreasing clarity of the lens would later require cataract surgery with IOL implantation, which would involve further surgical costs (although not necessarily born by the patient himself). An additional complicating factor of this eventuality would have been that IOL formulas require the adjustment of K values for previous keratorefractive surgery and can be difficult as well as error-prone.
The patient's hyperopia qualified him for midperipheral collagen-shrinking technologies. Available in various forms for more than 20 years, these technologies have an enviable record of safety but have been plagued by refractive instability; the obtained correction tends to drift back with time to the original degree of hyperopia. As with LASIK, I considered that the patient would eventually need cataract surgery after an intervening period of visual decline. Once again, the IOL formula would require adjustment, this time with the additional uncertainties of corneal stability and the smaller population of HTK-treated eyes available for analysis of its effect on keratometry-dependent visual function.
Supporters of the Array multifocal lens (Advanced Medical Optics, Inc., Santa Ana, CA) would probably consider this patient to be an ideal case for this IOL. Because the patient had never had normal near vision (as would an emmetrope or myope at an early age), inserting a multifocal IOL would restore a significant degree of both near and intermediate vision, in addition to the primary goal of uncorrected distance vision. Although many individuals have been successful with the Array, its use has been dogged by frequent complaints of nighttime halos and glare, and some surgeons find it difficult to determine which patients will tolerate these imperfections. High patient satisfaction depends on the absence of residual ametropia, particularly cylinder. Patients therefore may require further surgery, which entails additional risk and expense.
The availability of an FDA-approved, truly accommodative IOL would further strengthen the argument for refractive lensectomy. Monovision was an alternate visual strategy. Because the patient lacked interest in and a positive history of monovision contact-lens wear, we agreed on binocular surgery intentionally biased toward full distance visual function.
Small-incision lensectomy by phacoemulsification with a foldable IOL is a generally safe and reliable operation, the skills for which are already possessed by a vast number of general and specialty-trained ophthalmologists. Nevertheless, even its low, serious complication rate of 1:1,000 to 1:1,500 is significantly higher than that of LASIK. While near-blindness resulting from LASIK is a possible, although rare, complication, almost every cataract surgeon has had at least one regrettable experience with a severe complication such as endophthalmitis or expulsive choroidal hemorrhage. This situation could be even more devastating in the case of a patient with much of his life and career still ahead of him.
J. Trevor Woodhams, MD, is Surgical Director of the Woodhams Eye Clinic in Atlanta. He holds no financial interest in the product mentioned herein. Dr. Woodhams may be reached at (770) 394-4000; trevorw@mindspring.com.
