Todays presbyopia patients have more vision correction choices than ever before. And for those patients with aging eyes who opt for refractive surgery instead of contacts or ophthalmic lenses, they may have even more options available to them right around the corner.
Case Report: The Nighttime Driver By Paul M. Karpecki, O.D. Patient History and Diagnostic Data A 61-year-old white female presented with uncorrected vision of 20/200 O.D. and 20/400 O.S., which was correctable to 20/25 O.U. with -3.50D0.50Dx180 O.D. and -3.75D0.75D x175 O.S. contact lenses. The patient is a long-standing contact lens wearer who has demonstrated success in monovision contact lenses. Management Discussion
Now, presbyopes have myriad refractive surgery choices to select from, including multifocal and accommodative IOLs, conductive keratoplasty (CK) and monovision LASIK through a wavefront-guided platform, just to name a few. As new technologies and techniques continue to surface, other promising surgical options may be available in the near future that can correct presbyopia without removing tissue from the eye.
Slit lamp exam revealed normal lids, clear corneas, and a deep and quiet anterior chamber, but showed the presence of grade 2+ nuclear sclerotic cataracts (NSC) O.U. A glare test was conducted, and the patients vision decreased to 20/80 O.D. and 20/100 O.S. Dilation showed the presence of early cortical cataracts as well as grade 2+ NSC. The fundus exam was unremarkable.
Treatment options were discussed, including accommodative IOLs, multifocal IOLs and monovision cataract surgery. The patient noted that she drove a town car as a part time job in the evening and on weekends. The patient was very hesitant about any technology that could compromise her night vision; however, she did not want to lose her reading vision with monovision contact lens.
Laser vision correction was contraindicated due to the presence of cataracts that produced glare testing worse than 20/50 O.U. Due to her occupation, we decided not to pursue multifocal IOLs. The two remaining options were either monovision after cataract surgery or the Crystalens accommodative IOL (eyeonics). The patient was very interested in the accommodating IOL option, despite her tremendous success with monovision contact lenses.
The patient discussed the options with her husband, and they decided on the monovision cataract procedure because of financial considerations and the previous success she had experienced with monovision. She selected the Bausch & Lomb SofPort lens since it is a neutral aspheric IOL. Its design will improve her night vision. Additionally, the SofPort has been shown to extend depth of focus for monovision.
Here is whats current, whats new and whats on the horizon in refractive surgery for your presbyopic patients.
New Developments
The promise of corneal inlays to correct presbyopia is receiving a strong buzz from eye care professionals. AcuFocus launched clinical trials in 2006 for a corneal inlay called the ACI 7000. Earlier this year, Bausch & Lomb announced a business partnership with AcuFocus for this new technology. The corneal inlay has been designed to maintain normal corneal physiology and corneal health, and the procedure involves neither tissue removal nor permanent cornea alteration.
Recent studies have shown that the ACI 7000 improves near vision in patients who did not previously require vision correction, as well as in those who have undergone LASIK surgery. Trials are being conducted to study the ACI 7000 in patients with intraocular lenses, according to the company.
The inlays are made of biocompatible material that resembles the surface of the eye. Should this new approach to presbyopic refractive surgery gain approval from the FDA, it could prevent complications that may result from other surgeries, such as LASIK, since the tissue of the patients eye would remain undisturbed.
This technology is extremely promising, says optometrist Paul Karpecki, director of research at
CustomVue Monovision LASIK
In July of this year, the FDA approved Advanced Medical Optics CustomVue laser platform for performing monovision LASIK. This new approval for monovision correction utilizes the previously approved wavefront-guided treatments for myopia and astigmatism.
At the FDAs request, AMO/VISX will conduct a study post-approval, following 500 patients for six months after surgery to characterize quality-of- vision and quality-of-life issues associated with permanent LASIK monovision correction, according to the FDA.
The objective of the study is to estimate the proportion of monovision LASIK patients who experience visual disturbances that are severe enough to limit activities or adversely affect a patients quality of life.
There is still some debate on the optimal point of correction for presbyopia: the cornea or the lens, Dr. Karpecki says. Three procedures (LASIK, ACI 7000 and CK) all work on corneal modification, and a number of accommodative IOLs and multifocal IOLs work on the lens. The FDA approvals show that both optical systems work for the correction of presbyopia, he adds. Both structures can result in glare, halos and multifocality in a some patients, and both show great independence from spectacle use."
The approval of a presbyopic LASIK procedure will provide us with vast amounts of data to determine these answers, adds optometrist Brian Chou of
Actually, from a clinical standpoint, the approval doesn"t mean much because practitioners have been doing monovision LASIK all along, says Dr. Chou. However, it does have some implications. More refractive surgeons may specially market CustomVue as a treatment for patients needing bifocals. So, patients may inquire about monovision and presbyopia, he adds.
Case Report: The Extremely Hyperopic Presbyope By Anthony Tran, O.D. Patient History and Diagnostic Data A 51-year-old male presented with a chief complaint of extremely poor uncorrected distance and near vision that required him to be completely dependent on glasses his entire life. He was not interested in contacts because he would still be dependent on some type of vision correction device. His best-corrected vision was 20/25+1 with a refraction of +8.00D-2.50Dx167 O.D. and 20/25 with a refraction of +8.75D-2.75Dx017 O.S. Slit lamp examination revealed normal anterior segment findings, and there was no apparent pathology noted upon dilated fundus exam. Management Available treatment options to reduce his dependence on glasses were limited due to his extreme hyperopia and significant astigmatism. He was not interested in contact lenses. Maximum laser correction would still leave him with moderate hyperopia and not address his presbyopia at all. The only option that could realistically provide any independence from glasses would be a bioptic procedure. Discussion Although the maximum power for either the ReSTOR (Alcon) or ReZoom (AMO) multifocal IOLs was not as high as the Crystalens, either may have provided a satisfactory end result with a higher-powered piggyback IOL. However, the patient would be left with a much higher residual refractive error in the interim between the two IOL implantation procedures. Additionally, the patients specific visual needs had to be taken into consideration when selecting the most appropriate IOL. In this particular case, the patients extensive near and intermediate visual demands made the Crystalens the best choice.
This would consist of a refractive lens exchange (RLE) procedure with an accommodating or multifocal IOL, combined with limbal relaxing incisions (LRIs) to treat the astigmatism. Once the vision stabilized after this procedure, any residual hyperopia and/or astigmatism could be corrected with laser surgery or a piggyback IOL.
Based on preliminary calculations, we determined that an IOL with the maximum available power would be necessary to correct as much of his refractive error as possible. The Crystalens accommodating IOL (eyeonics) had the highest power available (33D), while the maximum power of the multifocal IOLs was 30 diopters.
We decided that the Crystalens would be the best treatment option, not only because of its high power availability, but also due to the patients occupation. As a post office clerk, the patient desired the ability to transition from computer distance to near. We discussed realistic expectations regarding the outcome of the procedure at length, including the strong possibility that he would still need glasses for certain distance and/or near activities.
Refractive lens exchange with the maximum power Crystalens IOL was performed in the left eye first, along with two 8mm LRIs to correct the astigmatism. At the two-week follow-up visit, his uncorrected vision was 20/100 O.S., which was correctable to 20/25 with a refraction of +3.50D-1.00Dx007. Refractive lens exchange with Crystalens was then performed in the right eye.
Three weeks later, the uncorrected vision was 20/80 O.D. and 20/100 O.S., correctable to 20/20-2 with +2.25D-0.50Dx174 O.D. and 20/25 with +3.25D-1.00Dx010 O.S. He was given separate distance and near glasses prescriptions to use temporarily until his vision stabilized and the second stage of the bioptic procedure could be executed. He was instructed to perform accommodation exercises through his distance glasses to begin the intermediate and near vision rehabilitation process with the Crystalens implants.
At the four-month post-op visit, uncorrected distance visual acuity measured 20/80 O.D. and 20/100 O.S., intermediate (32 inches) acuity was 20/50 O.D. and 20/50 O.S., and near acuity was J10 O.D. and J10 O.S. At this visit, he had mild posterior capsular opacification that progressed over the next couple months, which was ultimately treated with a laser posterior capsulotomy O.U.
At ten months, uncorrected distance acuity was stable at 20/60 O.D. and 20/100 O.S., intermediate acuity was 20/50 O.U., and near acuity was J10 O.U. The patients refractive error was +2.75D-0.75Dx159 O.D. (20/20-2) and +3.25D-0.75Dx111 O.S. (20/20-1). We discussed the options available to treat this residual hyperopic astigmatism: glasses, contact lenses, laser surgery or a piggyback IOL.
The patient preferred to further reduce his dependence on glasses if possible, so we went into greater detail about the two surgical options. We ultimately decided in favor of the piggyback IOL due to the rapid recovery, better predictability regarding the amount of residual hyperopia being treated, and the fact that no additional incisions would be necessary with a second IOL implantation.
Sulcus implantation of a Staar silicone IOL was performed in the left eye first. On day one, the uncorrected vision had already improved to 20/25 at distance, 20/20 at intermediate and J3 at near. One week later, a Staar silicone IOL was implanted in the sulcus of the right eye. The one-day post-op visit for the right eye also revealed a significant improvement in uncorrected vision, measuring 20/25 at distance, 20/20 at intermediate and J3 at near.
At the one-month post-op visit, his unaided acuity was relatively stable: at 20/25 O.U. at distance, 20/20 O.U. at intermediate and J2 O.U. at near, with a residual refractive error of Pl-0.75Dx150 O.D. and Pl-0.75Dx105 O.S. Needless to say, the patient was ecstatic with the final results of the bioptic procedure, giving him the independence from glasses that he never imagined possible. We instructed him to continue his accommodation exercises, as his near vision was expected improve even more over time.
Regarding correction of the residual refractive error following IOL implantation, there is often debate over whether laser surgery or a piggyback IOL is a better option. There are several factors to consider, including the amount of the residual refractive error, ocular surface issues, surgeon expertise with both techniques, and, with the case of a piggyback IOL, anterior chamber depth. The decision must be made on a case-by-case basis, as each alternative presents its own set of risks and benefits.
Intraocular Lenses
Presbyopia-correcting IOLs have been on the market in the
AcrySof ReSTOR (Alcon) is a multifocal IOL that gained FDA approval in March 2005. It uses apodized diffractive technology to provide near, intermediate and distance vision. Such an optic design allows it to focus light correctly on the retina for viewing images at numerous distances.
Clinical studies previously reported that 80% of those who received the lens did not wear glasses for any activities after their cataract surgery; 84% of patients who had lenses in both eyes had distance vision of 20/25 or better, and near vision of 20/32 or better.
The other multifocal on the market is ReZoom (AMO), which also received FDA approval in March 2005. This second generation multifocal distributes light over five optical zones, with three zones blended out from the original array design. Each zone is designed for different light and focal distances.
The ReZoom has proportioned the size of its zones to provide for good vision in a range of light conditions. Some zones have been designed to offer greater low light/distance vision support during night driving, according to the company.
Crystalens (eyeonics) is a singlefocus accommodative lens that received FDA approval in 2003. It remains the only accommodative lens on the market. The Crystalens comes equipped with a hinged haptic on either side, which permits ease of movement and allows the eye to focus more naturally.
The lens technology was recently modified, which appears to have improved its design and function, Dr. Karpecki says. The optic zone has been increased from 4.5mm to 5.5mm, and the haptics have been modified to prevent both movement in the capsule and the potential Z-phenomenon, where the IOL can shift on an angle. These modifications appear to have increased the accommodative capacity as well, Dr. Karpecki says.
Conductive Keratoplasty
Since the procedure gained FDA approval in April 2004, conductive keratoplasty has been considered a staple in refractive surgery vision correction for presbyopia.
CK remains a viable option as a niche play in presbyopia, especially for presbyopic correction after previous surgeries, Dr. Karpecki says. Although it is most effective at treating low hyperopia or
presbyopia. Rather than lifting the flap or trying to do a surface hyperopic ablation, eight CK spots at 8mm in one eye are a quick and effective treatment.
Patients must be informed that the positive effects of the procedure may diminish over a two- to seven-year period, necessitating another treatment, Dr. Karpecki adds.
Pending FDA approval, other new surgery options may become available, including presbyopic LASIK, laser presbyopia reversal and surgical reversal of presbyopia with scleral expansion bands.
The Future?
So, what else does the future hold in refractive surgery options for presbyopes? The future holds great promiseperhaps the most exciting potential presbyopic corrections of the future are polymer injections, which could replace soft lenses and possibly restore accommodation, Dr. Karpecki says. We know that the ciliary body continues to work throughout our life. If we would replace the lens material inside the capsule with a pliable polymer with good optics, it could be a treatment for both cataracts and presbyopia.
Case Report: ReSTOR Versus ReZoom By Loretta Ng, O.D. Patient History and Diagnostic Data A 63-year-old female was referred for bilateral cataract surgery. The patient complained of decreased vision at both distance and near in recent months, as well as increased glare at night. Her vision was correctable to 20/50 O.D. with +1.75D-0.50Dx068 and 20/80 O.S with +1.75D-0.75Dx117. During glare testing, her acuity dropped to 20/60 O.D. and 20/100 O.S. Her pupils were 4.0mm O.U. under mesopic illumination. She is right-eye dominant. Detailed dilated examination of her anterior and posterior segments was unremarkable, except for Grade 2 nuclear sclerosis O.D. and Grade 3 nuclear sclerosis O.S. Management Presbyopic treatment options currently available for this patient with significant cataracts are traditional IOL implants in a monovision system, the ReZoom acrylic refractive multifocal IOL (AMO), the AcrySof ReSTOR acrylic multifocal IOL (Alcon), and the Crystalens accommodative IOL (eyeonics). The ReSTOR lens has a 3.6mm apodized diffractive central near zone consisting of 12 concentric steps of gradually decreasing heights with a power of +4.00D (equivalent to a +3.20D add at spectacle plane) surrounded by a refractive region for distance. As such, it is the ideal lens for those patients wanting excellent near vision, especially within a 16-inch (40cm) working distance. This IOL was the logical choice for our patient. The patient was very happy with her distance and near vision, but noticed that intermediate was quite difficult. Upon discussion with the patient, the surgeon decided to implant the ReZoom lens, instead of the ReSTOR, which provides better intermediate vision, in the right eye. To date, our clinic usually implants the same multifocal IOL in both eyes, as it theoretically induces bilateral visual summation. But on occasion, such as in this case, the result of the first surgery guided our decision to implant a different multifocal IOL in the fellow eye. Spending the necessary time to identify the patients visual needs at different distances for both work and play is the key to selecting the most appropriate premium IOL. The whole process is more effective when the referring optometrist plays a role both in educating patients on presbyopic IOL options and communicating the recommended IOL to the surgeon.
Other technologies include light-adjustable IOLs, which can be modified with laser or light treatment to alter the refractive error; these may even be reversible. The future is very exciting in the area of surgical presbyopic correction, Dr. Karpecki says. This is fortunate, since there will soon be over 90 million presbyopes in the
This patient was using rigid gas permeable contact lenses for distance and +2.50D readers for near. After discussing the surgical options, she expressed interest in presbyopic IOL implants. All of our cataract and refractive lens exchange patients are given a questionnaire that discusses the five lifestyle zones of vision, and queries their pertinent visual objectives. This method segregates common visual demands into five zones, or basic working distances, that most people use. The patient is then asked to identify the range of three consecutive zones that are the most useful to them. Our patient indicated Group A (zones 1, 2 and 3) to be the most pertinent to her daily activities, especially working distance within 16 inches (40 cm), due to her hobbies. The patients goal was to see clearer at distance, while being independent or less dependent on glasses for near. She had tried monovision several years ago, but was unable to adapt.
The patient had already tried monovision contact lenses without success, so monovision IOLs were eliminated as an option. Since our patient had less than one diopter of expectant post-operative astigmatism and no macular pathology or other conditions that might have compromised contrast sensitivity, all three presbyopic IOLs were viable options.
Crystalens draws on the theory that when the ciliary muscles constrict during accommodation, they redistribute the IOLs mass backwards, promoting an increase in vitreous pressure and a decrease in pressure in the anterior chamber. This pressure gradient causes the plus-powered, central hinged haptics of the Crystalens to shift forward, yielding the resultant accommodative effects. When accommodation is relaxed, the pressure gradient reverses and the optic shifts back into its original position.
In our practice we have found great intermediate vision with this lens after a few weeks, and with some effort from the patient (visual exercises after the second week), fair near vision can be obtained. The Crystalens is our presbyopic IOL of choice for patients with relatively large pupils under dim illumination or patients who require good night vision. As our patients near visual demands were paramount, we decided the Crystalens was not the ideal choice for her.
Both the ReZoom and ReSTOR lenses work best in patients with a pupil size of at least 3.5mm due to their multifocal design. Patients need to be aware that these multifocal IOLs can be associated with more halos at night, especially in patients with larger pupils. Considering that our patient has 4.0mm pupils, either multifocal IOL would be an appropriate lens. The main difference between the ReZoom and the ReSTOR is their relative superiority at different working distances.
The ReZoom lens evolved from the array with its balanced-view optics design that functions well at both distance and intermediate distance viewing. This is accomplished thanks to the aspheric transitions between its five concentric ringsa large central 2mm distance zone and four peripheral rings of varying sizes that alternate between near and distance power. Ultimately, three of the five rings are used for distance vision, as the other two are for near vision. This is our current lens of choice for patients with strong intermediate vision needs, such as computer use, menu and price tag reading, and other indoor activities.
During our discussion of IOL choices, we thoroughly educated the patient on the benefits and drawbacks of each lens and emphasized that none are perfect. For example, still having to wear glasses after surgery in certain situations is one potential drawback. Additionally, patients with multifocal IOLs may see nighttime halos. Our patient understood and accepted these issues, and we scheduled surgery with a bilateral ReSTOR IOL in the left eye for three weeks later.
At the one-week post-op visit, our patient was seeing 20/25-2 with a residual refraction of +0.25D-0.50Dx180 at distance and J1 (20/25) at 16 inches O.S.
One week after implantation of the ReZoom lens in the right eye, the patient saw 20/25+2 with J3 at 16 inches and J1 at computer distance. The residual refraction was -0.25D-0.50Dx050 O.D. The patient is extremely happy with her vision, and reports no problems to date, nor any need to wear spectacles. She is aware that some halos may appear at night.
Discussion
Equally important is evaluating the patients outcome following surgery on the first eye to help decide the appropriate IOL option for the second eye.
As with laser refractive procedures, the optometrist who has spent the most time caring for a particular cataract patients visual needs is also the best individual to provide comanagementfrom selection of the IOL to subsequent follow-up care.
