© 2020 MJH Life Sciences and Optometry Times. All rights reserved.
© 2020 MJH Life Sciences™ and Optometry Times. All rights reserved.
By Kenneth R. Mueller, OD
It is imperative to discuss intraocular lens (IOL) options with our patients requiring cataract surgery. Even if our patient is a poor candidate for a premium IOL, we want the patient to be well informed about what lenses are available. We certainly don’t want to upset the patient because we did not tell him about a fancy lens that his golfing buddy just received.
So, who should help the patient decide which IOL option to choose? The optometrist? The surgeon?
A strong case can be made for the primary eyecare professional to be the expert in the area of IOL choice. The primary eye doctor has the opportunity to know and understand the needs and personalities of his own patients and will have the duty of taking care of the ongoing visual needs of those patients for years after the cataract procedure is performed. He must, therefore, have a thorough understanding of the benefits and limitations of each IOL design.
If the cataract surgeon is not the patient’s primary care doctor, the optometrist and the surgeon must work as a team to agree on which of the available lens designs to offer and recommend.
We have few approved premium IOLs from which to choose in the U.S. Our colleagues outside of this country, however, are using several designs which may soon find their way to our shores. While the FDA is often criticized for being slow to approve IOL designs, this certainly is a double-edged sword. While we are anxious for new technology and options, we and our patients pay the price when results are less than optimal. Specially trained in optics, optometrists are aware of how a multifocal correction, whether it is in the form of a progressive eyewear lens or in a contact lens, can be completely unsatisfactory to a patient. Obviously, while it is fairly easy to remake a pair of eyewear lenses into a different design or to change from one multifocal contact lens to another, an IOL does not offer the same ease of changeability.
How should we go about making the IOL decision? For the primary eyecare provider, following are the steps you might take, with the assistance of your technicians and patient education videos to inform and educate your patient regarding this important decision.
Step One: You and Mrs. Smith decide that her cataracts are at the point that they should be removed.
Step Two: You briefly explain the procedure to Mrs. Smith, including what to expect regarding the procedure, where and by whom the surgery will be performed, and what the post-operative schedule will entail.
Step Three: Mrs. Smith needs to know that she has options regarding her implant. You tell her that not only will she see better without her cataracts, you can now use this opportunity to correct her eyesight so that she is less dependent on glasses or contacts. You explain that a single-vision IOL will help her to see well at one distance, usually far away, and that then she would need glasses or contact lenses for near and intermediate work. If she has over about 1.25 D of astigmatism, you might recommend a toric IOL.
You educate Mrs. Smith that she may elect to have an implant to correct both the distance and near vision and that there are multiple options depending upon her needs, some of which offer better near vision, low light vision, distance vision, etc. You also let her know that while a single-vision IOL is generally covered by Medicare or major medical insurance plans, she would pay extra for a premium IOL such as a toric lens or multifocal lens, and you or your technician would be able to discuss that cost in detail, along with any financing options that your practice offers. This is also an excellent time to mention that while these options may free her up from wearing a correction full time, there will probably be times when she will still wear correction, such as when reading small print, working on the computer, or driving at night, and that some options will be better than others for different situations.
Step Four: A separate visit may be ideal to decide upon an IOL. It is imperative to discuss wants, needs, expectations, hobbies, vocations, lighting issues, and willingness or unwillingness to spend more for a premium IOL, to ascertain which option would best suit her.
Additional cataract surgery examination protocol should include:
• Dry eye testing. As vision with multifocal IOLs in particular can be poor with under-treated dry eyes, you must not wait to discover ocular surface disease after the procedure. Pretreat with Omega 3s, Restasis (cyclosporine, Allergan), punctal occlusion, artificial tears, etc., until the ocular surface disease is satisfactorily controlled. In poorly responsive cases, patients may be best served with single-vision IOLs.
• Lid health evaluation. Clear up any blepharitis pre-surgery.
• Corneal topography Rule out keratoconus and pellucid marginal degeneration, and measure corneal astigmatism. The surgeon will need this information for optimal visual outcome.
• Biometry (such as with the Zeiss IOLMaster.) This allows for accurate IOL power prediction.
• OCT. Check for signs of maculopathy, such as age-related macular degeneration, because multifocal IOL designs may be a poor option when present.
• Aberrometry. Identify patients with extreme aberrations such as coma, spherical, and trefoil, which may make them poor multifocal IOL candidates.
Step 5: When fully satisfied that Mrs. Smith’s eyes are ready for their procedures, and you have chosen an IOL design, you are ready to schedule what should be one of the most rewarding events of her life.
Four general categories of IOLs are currently available in the U.S.:
• Single-vision IOLs. Single-vision IOLs provide excellent vision at one focal point for non-astigmats and can be used for monovision. As with accommodating IOLs, single-vision IOLs provide the most focused light to the retina and may be better the better choice for patients with maculopathy.
• Toric single-vision IOLs. Single-vision lenses with astigmatism correction, toric IOLs such as the AcrySof IQ Toric IOL (Alcon) allow patients with larger amounts of astigmatism to be corrected at one focal point without undergoing LASIK, PRK, or lateral relaxing incisions (LRIs).
• Diffractive multifocals. Alcon’s AcrySof IQ ReSTOR IOL and AMO’s Tecnis Multifocal IOL and ReZoom Multifocal IOL are examples. Diffractive designs use concentric rings to split light into multiple focal points. This type often provides excellent near vision but may cause haloing and poor low-light vision.
• Accommodating/pseudo-accommodating. The accommodating lens designs that are approved in the U.S. are Bausch + Lomb’s Crystalens AO IOL and newer Crystalens HD IOL, which are hinged, single-vision lenses which flex with the muscles of the eye to provide focusing at different distances. The Crystalens AO is thought to offer excellent distant and intermediate vision with variable near efficacy without the addition of low-powered reading glasses. The HD aims to improve near vision.
Outside the US, particularly in Europe, other designs are being used with varying degrees of success, some of which will be available in the U.S. in the future.
• Diffractive designs. The weakness of the diffractive platform is that light is split and lost, so lower light conditions tend to suffer. Newer designs attempt to minimize this. The Carl Zeiss AT Lisa IOL is a diffractive-refractive hybrid lens. PhysIOL’s FineVision trifocal diffractive IOL is another of this type, designed to overcome the problem of poor intermediate vision common to many of the bifocal diffractive designs.
• Toric multifocal IOLs. Carl Zeiss Meditec AT Lisa Toric and Alcon’s AcrySof IQ ReSTOR IOL Toric are diffractive designs which show promise of being approved for the U.S. market.
• Refractive designs. A refractive multifocal, such as the Lentis Mplus, uses zones of different powers either in a bifocal design, which creates two simultaneous images, or by using annular zones utilizing pupil size variations to create the appropriate aperture for varying focal points. They use induced higher-order aberrations to create increased depth of focus.
• Innovative accommodating lens designs. PowerVision’s FluidVision IOL uses silicone fluid stored in the haptics to change the shape of the lens upon accommodation. The Synchrony dual optic accommodating IOL by Visiogen/AMO is already in use in Europe but has not won FDA approval here. It has a moveable anterior optic, which is attached to a posterior optic by spring haptics. Many surgeons are excited by its early efficacy.
• Light adjustable lens (LAL). A novel design from Calhoun Vision of Pasadena, CA, is the LAL, made from photosensitive silicone. By shining a particular wavelength of light at the lens, the user can increase or decrease its power, including astigmatism, after which its power is locked in by using another light application. This lens is in clinical trials in the U.S., with hopes of gaining FDA approval.
As we have found with LASIK and multifocal contact lens patients, not everyone is the best candidate based upon expectations. The patient who is at 20/15 distance and J1 at near may be terribly unhappy because of glare at night, poor intermediate vision, or poor low-light vision, while the patient who is J3 at near may be perfectly happy wearing reading glasses for small print or in dim lighting.
Our premium IOL patients can be the happiest, most grateful people in our practices. It all comes down to proper patient selection, lens choice, and educating our patients about what they can truly expect from a lens. These lenses are very good, not perfect. Even if our patients are much less dependent upon glasses, as opposed to being totally free of glasses, many of our patients will be thrilled with very good…and tell all of their friends.ODT