Patient selection, preoperative evaluation critical for success

Frank A. Bucci Jr.

Multifocal IOLs, such as the ReZoom IOL (Advanced Medical Optics [AMO]) and the ReSTOR IOL (Alcon), can offer patients with cataracts presbyopia correction, in addition to treating cataract.

Proper patient selection is the first important step to ensure successful multifocal IOL implantation and can greatly increase the number of satisfied patients. I find that the ReZoom multifocal IOL provides patients with improved near and intermediate vision. The number of potential candidates for multifocal IOL implantation, therefore, is increased.

Some patients, however, are unsuitable for multifocal IOL implantation, and careful patient selection is, therefore, imperative.

Patient needs, expectations

Preoperatively, the surgeon should discuss the option of multifocal IOLs with patients with cataracts. The surgeon should interact with patients to develop a relationship and to determine their vision needs. In addition, surgeons must educate patients preoperatively so they know what outcomes to expect, increasing the likelihood of patient satisfaction. Patients are more likely to tolerate expected outcomes than unanticipated outcomes. Furthermore, surgeons must understand the vision demands of each patient and should take time to learn about each patient’s daily activities, such as night driving habits, computer use, reading habits, and sports or performance activities. For example, a night-time taxi driver in New York City may look at point sources of light all night. An IOL that could create glare, therefore, is not an appropriate option for this patient.

In addition to evaluating a patient’s vision needs, surgeons should also determine whether a patient is tolerant or demanding. Evaluating the patient’s traits will greatly affect the surgeon’s management of patient expectations.

Stress functional vision

The goal of implanting a multifocal IOL in patients is to reduce dependence on glasses. In the preoperative discussion, surgeons should explain to patients that visual outcomes might not be as clear as outcomes with glasses, but I believe patients will be happy when provided with the best possible distance, intermediate, and near vision. The goal of implanting a ReZoom IOL is to achieve reasonable distance, intermediate and near vision, and surgeons should stress that, for most patients, the ReZoom offers independence from glasses for most activities and the ability to perform most daily functions without reading glasses. In fact, 93% of patients implanted with ReZoom IOLs have independence from glasses for distance and intermediate vision, and 81% have independence from glasses for near vision (Figure 1).¹

Independence from glasses Figure 1. Product labeling shows that 93% of patients implanted with ReZoom IOLs have independence from glasses for distance and intermediate vision, and 81% have independence from glasses for near vision.1 Source: Advanced Medical Optics

With reasonable expectations, ReZoom’s strengths can be emphasized. In my clinical experience, the ReZoom IOL offers patients excellent distance vision in bright light, reading vision in low light, and intermediate vision for many of today’s functional tasks, such as using a computer. In fact, intermediate vision needs may be increasing, as a recent AARP survey suggests. Study results published in AARP’s The State of 50+ America 2006 show that Internet use among the older population is increasing (Figure 2). ²

Intermediate vision is also necessary to accomplish other tasks, such as serving and eating food, looking at a wristwatch or dashboard gauges, and dialing on a cellular phone, among others.

Internet use and the aging population Age 1998 2005 Increase 50 to 64 years 31% 65% 2.1 x 65 to 74 years 12% 45% 3.8 x 75+ years 4% 25% 6.3 x Figure 2. Intermediate vision needs may be increasing. Study results demonstrate increased Internet use among the older population.2

The ideal patient

Patients who have an acceptance of realistic goals and motivation to reduce dependence on glasses are favorable candidates for multifocal IOLs. Motivated patients are more willing than other patients to tolerate the process of reducing dependence on glasses with multifocal IOL implantation and to recognize that some time is required to adapt to the new visual system.

Patients with cataracts, with or without presbyopia, are also ideal. In addition, patients who are candidates for bilateral implantation, as well as patients with hyperopia, are preferred.

The ideal patient will also understand that loss of contrast is possible. Surgeons should explain that in addition to possible contrast loss, patients may experience glare or halos and that glasses may be necessary for work requiring prolonged near vision.

Patient acceptance of the process with multifocal IOL implantation also relies on the knowledge that a second procedure may be necessary. I inform patients that about one third of all patients will require another procedure to treat residual spherical error or residual astigmatism.

“Patients who have an acceptance of realistic goals and motivation to reduce dependence on glasses are favorable candidates for multifocal IOLs. ” —Frank A. Bucci Jr., MD

Surgeons should carefully consider patients who have unrealistic expectations and who are overly critical, such as patients who complain of significant glare with contact lenses. Patients with night-time occupations, as well as pilots, should also be carefully considered.

Previous refractive surgery or the potential for progressive keratoconus or age-related macular degeneration may also be concerns for multifocal IOL implantation.

I recommend that the first ReZoom IOL implantation be performed on a patient with bilateral cataracts that reduce best corrected visual acuity. The patient should be glasses-dependent, have hyperopia and presbyopia, and anticipated postoperative astigmatism of < 0.75 D. This patient should also be optimistic and have normal ophthalmologic examination results and no systemic disease.

In my experience, the most unlikely candidate for multifocal IOLs has presbyopia and < 4 D of myopia, has worn glasses for distance vision for most of his or her life, and has better near than distance vision.

Preoperative evaluation

A patient’s preoperative evaluation can help avoid any condition that will delay or eliminate the promised or anticipated postoperative result. Surgeons performing a preoperative evaluation should also consider each patient a potential laser vision correction patient. Surgeons should review a patient’s medical and surgical history and be careful with patients who have diabetes or collagen vascular or autoimmune disease. Other concerns include previous ocular or corneal surgery and previous and existing ophthalmic conditions, such as glaucoma, strabismus, amblyopia, and dry eye.

“A patient’s preoperative evaluation can help avoid any condition that will delay or eliminate the promised or anticipated postoperative result.” —Frank A. Bucci Jr., MD

Patients who wear soft contact lenses should discontinue lens wear at least 2 weeks before examination, and patients who wear hard or rigid gas-permeable (RGP) lenses should discontinue lens wear at least 3 weeks before examination for reliable keratometry readings in the preoperative evaluation. A stable ocular surface with reliable keratometry readings is desired. Hard contact or RGP lens wearers should have keratometry readings taken at 1-week intervals, and the last two readings must not differ by > 0.5 D.

In the preoperative examination, surgeons should also determine eye dominance, visual acuity, and refraction. The keratometer must be calibrated, and surgeons should perform a pupillary examination, measuring in bright and dim light illumination. Corneal topography is necessary for all patients to rule out keratoconus or any other abnormality, to check ocular surface quality, and to plan for astigmatism management.

Surgeons should also confirm agreement between the topographic and keratometric cylinder; otherwise, I advise surgeons to proceed carefully and repeat measurements. Astigmatism is not always reflected on keratometry readings, however. Topography thus may be helpful in diagnosing irregular astigmatism.

Additional tests

Adequate assessment for dry eye is also important and can be performed using slit lamp examination. Although multifocal IOL implantation will not worsen a patient’s dry eye, visual recovery may be delayed if the condition is not treated. A healthy ocular surface is also necessary to obtain reliable keratometry readings. Preoperative evaluation of precorneal tear film and ocular surface is necessary and can be accomplished using Schirmer’s test, fluorescein staining, or vital dyes.

Slit lamp examination will allow surgeons to identify patients with pseudoexfoliation syndrome or corneal guttata or Fuchs’ dystrophy. Patients with corneal guttata or Fuchs’ dystrophy are at risk of reduced visual function, disease progression, and postoperative corneal edema and, I believe, are not good candidates for multifocal IOL implantation.

Surgeons should also perform tonometry, pachymetry, and dilated media and fundus examination in the preoperative evaluation of possible candidates for multifocal IOLs. A dilated media and fundus examination will help surgeons avoid patients with any retinal pathology, such as diabetic retinopathy and age-related macular degeneration.

The eight Ps Surgeons can use the eight Ps as a checklist for correcting presbyopia. The eight Ps, which summarize key issues of treating patients with multifocal IOLs, include: Patient selection, which is critical; Preoperative counseling to manage patient expectations; Preoperative examination, especially of the cornea and retina, to assess visual potential; Presbyopia-correcting IOL selection; Phacoemulsification and IOL implantation that are efficient and accurate; Plano +/- target obtained so that distance vision is not reduced and residual refractive error is aggressively treated; Posterior capsular opacification treated early because patients have already lost some contrast sensitivity; and Psychophysiology, which is important to facilitate continued neuroadaption. Source: Bucci FA

Pearls for calculating IOL power

Preoperative measurements are key to IOL power accuracy. Both eyes must be measured preoperatively to obtain an accurate IOL power. Components for accurate IOL calculations include accurate keratometry, biometry, and IOL power formula, as well as an appropriate surgical technique.

Keratometry values should be within 1.5 D between eyes. If the difference is > 1.5 D, the surgeon should repeat measurements. Measurements should also be repeated if cylinder is > 4 D. In addition, surgeons should reconfirm keratometry if readings are < 40 D or > 47 D.

Biometry can be obtained with applanation A-scan, immersion A-scan, or optical coherence biometry with the IOLMaster (Carl Zeiss Meditec). In my experience, applanation A-scan, which depends highly on the operator, may offer falsely short axial length measurements due to varying amounts of corneal compression. Immersion A-scan is more consistent than applanation A-scan, is less operator dependent, and does not have direct corneal contact or corneal compression. In using immersion A-scan, a surgeon should have the patient lie in the supine position. The scleral shell should be placed between the eyelids and centered over the cornea, then filled with balanced salt solution with the probe tip in the solution. The surgeon should align the ultrasound beam with the macula by having the patient look at the probe tip fixation light, then take readings as usual.

The IOLMaster is a noncontact optical coherence biometer that allows measurements of axial length and surface curvature. Similar refractions should have similar axial lengths. Axial length should correlate with the clinical picture, including keratometry and refractive error, and should be within 0.33 mm between eyes. If axial length is < 22 mm or > 26 mm, surgeons should proceed with caution.

I also recommend that surgeons develop a personalized A constant and encourage careful, ongoing restrospective analysis of results. Surgeons should strive to be within 0.5 D of their refractive targets in more than 90% of patients.

In addition, I target the ReZoom IOL power to be plano or slightly minus for some patients, as well as plano in one eye and slightly minus in the other eye for other patients.

Axial length-based formulas are important in multifocal IOL implantation. I recommend that surgeons use the Holladay II or Hoffer-Q formulas for patients with < 22 mm in axial length; the Holladay I, Hoffer Q, or SRK-T formulas for patients with axial length between 22 mm and 26 mm; and the SRK-T or Holladay II formulas for patients with axial lengths > 26 mm.

Good refractive outcomes in patients with multifocal IOL implantation are difficult to achieve if patients had previous keratorefractive surgery, keratoconus, extreme axial myopia with posterior staphyloma, nanophthalmic eye, or silicone oil lens coverage.

With careful patient selection and thorough preoperative evaluation, multifocal IOL implantation can be successful and result in satisfied patients.

References

1. ReZoom Acrylic Posterior Chamber Intraocular Lens [package insert] Santa Ana, Calif: Advanced Medical Optics, Inc.
2. Beedon L, Southworth L, Gist J. The state of 50+ America 2006. Washington, D.C.: AARP Public Policy Institute; January 2006. Pub ID: D18469.

Frank A. Bucci Jr., MD, is founder and medical director of Bucci Cataract and Laser Vision Institute in Wilkes-Barre, Pa.

Mixing and matching eliminates complaints Frank A. Bucci Jr., MD With voluntary intermediate vision complaints increasing among my patients with bilateral ReSTOR IOLs (Alcon), I decided to compare the effects of a ReZoom (Advanced Medical Optics)/ReSTOR combination with bilateral ReSTOR IOLs. In the first cohort, 55 patients were implanted with bilateral ReSTOR IOLs with a mean follow up of approximately 27 weeks. Twenty-two patients in the cohort underwent cataract surgery, and 34 had lensectomies. Fifteen of 55 patients offered voluntary intermediate vision complaints. Eleven of the 15 had lensectomies, and 10 of the 11 were younger than 60 years. One of the patients in this cohort is a 48-year-old woman with high myopia who underwent lensectomy with bilateral ReSTOR IOLs. She achieved 20/20 uncorrected distance vision and uncorrected near vision of J 1.00 in both eyes. Her bilateral intermediate uncorrected visual acuity was J 6.00, however. This patient complained that she could not see her desk or computer. Since surgery, she wears + 1.25 spectacles 8 hours a day. The second cohort included 95 patients implanted with ReZoom/ReSTOR. Data are available on 39 patients with at least 21 weeks’ follow up. To date, none of the patients implanted with ReZoom/ReSTOR IOLs offered any voluntary intermediate vision complaints. One of the patients in this cohort is a 58-year-old man with myopia who underwent lensectomy and was implanted with a ReSTOR IOL in one eye. He achieved 20/20 uncorrected distance vision and uncorrected near vision of J 1.00. Intermediate vision was J 6.00, however. The patient said he would not be able to tolerate two similar eyes. After implanting a ReZoom IOL in the second eye, he achieved J 2.00 uncorrected intermediate vision in that eye. The patient’s uncorrected bilateral intermediate vision is J 1.00, and the patient is extremely happy. A comparison of bilateral near vision between the cohorts demonstrates no statistical difference. Patients implanted with bilateral ReSTOR IOLs achieved a mean bilateral near vision of J 1.00; patients implanted with ReZoom/ReSTOR IOLs achieved J 1.07. A comparison of bilateral intermediate vision between the cohorts, however, demonstrates a statistically significant difference (P = .0001). Patients implanted with bilateral ReSTOR IOLs achieved a mean bilateral intermediate vision of J 3.81; patients implanted with ReZoom/ReSTOR IOLs achieved J 2.39. My colleagues and I concluded that a combination of ReZoom and ReSTOR IOLs is statistically and clinically superior to bilateral ReSTOR IOLs. One of every four patients implanted with bilateral ReSTOR IOLs volunteered an immediate vision complaint. One of every three lensectomy patients with bilateral ReSTOR IOLs volunteered a complaint. In contrast, the ReZoom/ReSTOR combination appeared to completely eliminate intermediate vision complaints. The unique optical characteristics of each multifocal IOL appear to be complementary. In this clinical experience, the synergistic effect results in high rates of spectacle independence and high levels of patient satisfaction.