Surgeons seek best IOL match for patients after cataract surgery.
Matching patients to the correct lens is becoming an art because of the advances in technology, and what was once a choice of monofocal, monovision, monofocal plano, and monovision near vision 20 years ago is now much more.
Neda Shamie, MD, cataract, LASIK, and corneal surgeon and partner of the Maloney-Shamie Vision Institute in Los Angeles, California, described 2 cases and how she determines the best course of action for individuals.
“Cataract surgery is now a fellowship of its own,” Shamie said. “The nuances of how to match patients to the right options are incredible. Physicians really need to understand the patients and what their needs are.”
Shamie said she often finds that involving the family in the decision-making process is helpful because they can shed more light on the lifestyle of the patient, and careful questioning of the patient uncovers how they use their vision on a daily basis.
This patient was a 65-year-old professor who wore contact lens monovision in the left eye until about 3 to 5 years previously because it was no longer serving her well, likely because of cataract development.
The patient conducted her classes in a lecture hall and wanted to be able to see the students in the first and last rows, ie, distance and near vision, and be able to view the monitor and see her notes.
To pinpoint this patient’s needs, Shamie asked a number of very specific questions, such as whether she put on her glasses or contact lenses upon awakening or later when leaving the house?
Some patients may apply makeup or read without glasses/contacts and later use them during the drive to work. Consequently, these patients may miss their reading vision.
Shamie explained that often myopes do not realize that to maintain that myopic focal point to which they are accustomed, they have to trade off the distance vision with cataract surgery. Surgeons must have these conversations with their patients. If a patient explains that she does not wear glasses or contacts until noon when she drives to lunch, but she does not want to wear glasses for driving, the surgeon must explain that that scenario is achievable, but she will need a magnifier when using her near vision to apply makeup, or that there is the option of monovision that requires an adjustment period.
A newer option is trifocal correction for patients who want a full range of vision. However, considering the visual needs of the professor under discussion that choice might not be tolerable. When dry eye is factored in, multifocality might not be a good choice.
An option for patients who use monovision is the extended depth-of-focus lenses, which provide great distance vision but not near vision. An option for a myope accustomed to reading at a comfortable distance is mini-mono with an extended depth-of-focus lens, which moves the near vision slightly closer at the expense of the distance vision.
Shamie said she is partial to the Light Adjustable Lens (LAL; RxSight), an IOL implant made of special material that reacts to light delivered to it. Postoperatively, when the refractive error has stabilized, the refractive target for the patient is determined and plugged into the in-office light delivery system, which exposes the IOL to a pattern of light that changes the refractive power of the lens.
“This technology has caused a paradigm shift in cataract surgery. It’s the wave of the future: titratable monovision,” she explained.
These IOLs require a few postoperative visits to achieve the targeted correction. Shamie recommended the light applications be done every 7 days; that schedule provided better results than treatments scheduled every 3 days.
Mixing and matching patients with different IOL designs is another option in which a multifocal can be implanted in 1 eye and an LAL in the other eye. The choices can be complex and the best results are achieved when the patient’s lifestyle and ocular pathologies are considered.
She also discussed toric correction and that multifocal lenses can be toric lenses. In addition, LAL also can treat astigmatism.
“LALs are actually a very good option for patients with astigmatism,” she commented.
Shamie presented this patient with 2 recommendations: the LAL with titratable monovision, plano in the right eye and –1.5 diopters in the left eye; or a toric monofocal IOL in both eyes, plano in the right eye and –2 diopters in the left eye with the hope that she would be satisfied with the refractive outcome.
This patient was a 56-year-old photographer. He needed to toggle between subjects in the distance and midrange and he complained bitterly of glare; he also needed astigmatic correction. He was advised by the referring doctor to get a standard IOL implant. His right and left eye visual acuities were 20/25 and 20/20, respectively.
Because this patient may be hyperopic, a multifocal IOL may be a good choice. Despite the glare, the vision is 20/20, but he is developing a cataract. He may want a full range of vision, but Shamie wants to carefully select her options.
She said a standard lens and a monofocal plus lens that is not diffractive, an LAL, is a reasonable option. The choice depends on what the patient hopes to gain and the willingness to invest the time and money.
In patients with a mild cataract, she may ask them to wait longer until the cataract develops further and not do a refractive lens exchange because they may still have some residual accommodation or because any existing dry eye may worsen. Performing a surgery at this point will not result in much of a difference in the vision.
“I want to make sure that they know what they’re getting themselves into,” Shamie said. “A post-LASIK patient who invested in their vision and now is using glasses may want to be spectacle independent; when I see signs of cataracts, implanting the LAL is a good option.”
Moreover, Shamie explained that if a patient has dominant monovision or monovision with LASIK and returns for refractive lens exchange or cataract surgery, she does monovision for them. If a patient has never had monovision, she tends to target plano for both eyes, or if their vision is good and the dominant eye can be determined, she may do a little mini-mono vision, that is, plano and they’re dominant, –0.5 or –0.75 diopter.
“The benefit with a LAL is that the lens can be titrated more for near vision, up to 2 diopters more for near vision. If you start at –0.5 diopter, you can even get them to –2.5 diopters and really push the monovision,” she said. “However, with a history of monovision, I start off with monovision planned. With the LAL, if their monovision history was a near vision with –1.75 diopters, I start with –1.0 diopter because adjusting them toward –1.75 diopters, sometimes even –1.25 diopters, gives them that extended depth-of-focus effect and a greater range of vision.”
Shamie said she also advises that with the LAL, patients must understand that there is not an infinite number of adjustments that can be done. In her practice, she explains that after the planned number have been performed, they cannot change their minds. If the patients cannot decide on a target, they do a contact lens trial first.
For the patient under discussion, she discussed toric, nonrefractive, and extended range of vision (Vivity; Alcon) options.
The multifocal lenses may be associated with neuroadaptation issues that can result in delayed responses to the implant.
“Patients may not be able to read or be able to appreciate the promise of that lens right away,” Shamie explained. “It can take time for someone to get accustomed to their new IOL and neuroadaptation. The most important thing as a surgeon is to make sure that before the surgery you clearly present the limitations and benefits of each technology offered to the patient.”
When she discusses the refractive option for a patient, she begins with the option that she thinks is best based on how they use their eyes throughout the day. This approach streamlined the practice and eliminated any confusion that patients might have had when presented with every possible option at once.
Neda Shamie, MD
Shamie is a cataract, LASIK, and corneal surgeon and partner of the Maloney-Shamie Vision Institute, Los Angeles, California. She has nofinancial interest in this subject matter.