December 2019

IN FOCUS

Examining presbyopia treatments
‘Blended vision’ for presbyopia patients


by Ellen Stodola EyeWorld Editorial Co-Director


Dr. Rebenitsch’s practice simulates monovision by
adding plus in the nondominant eye until the patient loses stereopsis.
Source: Luke Rebenitsch, MD

A sheet used by Dr. Kugler with every patient being evaluated for refractive or cataract surgery. Patients initial by the line corresponding to the level of near vision they expect to achieve after surgery, which helps Dr. Kugler and his practice guide them to the solution that is best able to achieve that, including blended vision for some people, or use the tool to set more realistic expectations, if their desired result is not achievable.
Source: Lance Kugler, MD

When faced with presbyopia correction, there are a variety of options for these patients. Brandon Baartman, MD, Lance Kugler, MD, and Luke
Rebenitsch, MD, discussed using monovision, particularly highlighting which patients do best with this option, potential concerns, special testing, and other considerations.

What percent of your presbyopic laser vision patients choose monovision?

Dr. Kugler said he uses this option in his practice for around 80% of patients over 43 years old. He stressed the importance of referring to it more as “blended vision” rather than “monovision.” Monovision implies that the near eye is seeing closer than blended vision, he said. Blended is less near in the near eye, which allows the brain to blend the vision better together. He said almost all patients can tolerate –1 or –1.25 D in the nondominant eye, and it gives them almost a full range of vision.
Dr. Baartman said monovision accounts for less than 10% of the laser vision correction in his practice. “However, those for whom I do perform monovision laser often swear by its results, making it something I’m certain to discuss with all eligible patients,” he said. “It is generally those myopic presbyopes, who have grown tired of bifocal spectacles or looking over or under their single-vision lenses, who opt for this method of presbyopic vision correction in contact lenses and choose to recreate this without the use of contacts.” He added that it’s critical to not only explain what the correction will do to uncorrected near vision but to show patients as well. For the presbyopic age group, Dr. Rebenitsch agrees with Dr. Baartman. “Blended vision is around 10% of my treatments for the presbyopic age group; 20% choose distance only, while 70% choose refractive lens exchange with a multifocal IOL. It does depend on where they are “coming from.” For myopes I am more likely to recommend blended vision. If they do not adjust as hoped, we will do a flap lift enhancement at no cost to bring them to full distance correction in both eyes. For hyperopes we tend to recommend distance only or RLE,” Dr. Rebenitsch said.

What are the negatives you cover with them?

For monovision/blended vision candidates, who are typically in their 40s and early 50s, Dr. Rebenitsch said it’s important to ensure the lens is clear. “We also simulate blended vision in the clinic,” he said, adding that he can typically tell within a few minutes if patients are likely to neuroadapt quickly.
Dr. Baartman said that the conversation with the 40 to 50-year-old refractive surgery consult is often the most nuanced of conversations in the practice of comprehensive refractive surgery. “Patients often come in envisioning the perfect solution for their problem, many having had friends and relatives that have
enjoyed excellent outcomes from LASIK in their younger, pre-presbyopic years,” he said. “Whenever discussing the option of monovision laser with patients of this type, I explain that the drawbacks to this solution include a loss of depth perception, contrast sensitivity, and image blur in one eye or the other at any distance.” Dr. Baartman added that the brain generally adapts to this and suppresses the blurrier of the two images, but there are still instances where the blur may cause problems, including while driving or reading in dim lighting conditions. “I make sure to tell them that this option often requires spectacle use while driving, particularly at night,” he said.
Dr. Kugler said you certainly have to be careful with determining which eye to treat for near vision. Sometimes, patients might be left-eye dominant, but they have certain activities where they’re using the right eye as dominant, he said. If you suddenly take that eye and make it see near, those activities could be difficult for them. Part of that conversation is explaining that whatever you’re choosing for the near target is not going to see distance as well, he added. It’s also important to counsel patients about the adaptation period.

Any preoperative testing that is special to these patients?

Determining the dominant eye is really important, Dr. Kugler said, even though he believes patients still tolerate it well if you make the dominant eye near. “We’ll certainly use contact lens trials in certain situations,” he said. However, he noted, two problems with this are that people spend a lot of time on how the contact feels rather than the vision. If somebody likes the contact lens trial, they’ll like blended vision LASIK, but if they don’t like contact lens trial, they’ll still probably like blended vision LASIK, as a few days isn’t necessarily enough time to determine if you’re going to blend it with your vision, he said.
The presbyopic age is complex, Dr. Rebenitsch said, so he recommended careful ocular analysis. We want to make sure the macula is healthy without early AMD or epiretinal membrane, he said, adding that it’s also important to look for the ocular surface disease. “For anyone who has poor ocular surface, blended vision is even more likely to cause blurry, fluctuating vision,” he said, adding that he will treat the ocular surface first, if needed, and likely recommend a lens-based option instead.
Dr. Baartman will always personally perform a precision refraction at distance and show non-emmetropic patients what their best-corrected vision can be with both eyes at distance.
It’s important for patients to understand the limitations their own eyes are setting, Dr. Baartman said. “With loose lenses, I’ll then add power to their non-dominant eye until they love the monocular near vision and then show them what it looks like with optimal monovision correction at both distance and near,” he said. If they are accepting of this, and the remainder of exam and testing shows good candidacy for corneal-based refractive surgery, Dr. Baartman provides a contact lens trial for at-home, real-life use to ensure this is something they want to commit to.

Do you do laser vision monovision for plano presbyopes? Do you do anything different in your process?

Plano presbyopes are one of the best challenges to the comprehensive refractive surgeon’s chairside chat, Dr. Baartman said. “This is one scenario where all options must be openly discussed and very detailed conversations are had about vision correction, including monovision LASIK and refractive lens exchange,” he said. “Some of these patients may be disappointed to learn that laser vision correction for enhanced reading vision, in most instances, will be gained at a mild sacrifice to binocular distance vision or depth perception.”
Depending on lens status, Dr. Baartman said some of these patients are better candidates for refractive lens exchange and opt for this. In those that are motivated to give monovision a try, he often uses longer trials of contact lens monovision to ensure this is a suitable option for their visual needs and lifestyles. “I’ll often work with the patient’s local optometrist to arrange a proper fitting and prescription, so we can identify the perfect monovision correction, and feel confident when we proceed to the laser suite,” he said.
Dr. Rebenitsch said that his decision would depend on a case-by-case basis. For someone who is younger, we’d opt for blended vision with laser vision correction, he said. But for those age 50 and older, he would recommend refractive lens exchange in one or both eyes, depending on the refractive status and level of dysfunctional lens syndrome. He added that these are “some of our happiest patients,” although a well neuroadapted person with blended vision can be just as happy, if not happier.
Dr. Rebenitsch also added that there are some technologies in other parts of the world that are not yet approved in the U.S., specifically PRESBYOND (Carl Zeiss Meditec). “In my mind it’s kind of monovision-plus,” he said, adding that this option increases the depth of focus through increased spherical aberration. It’s typically done in the non-dominant eye, and by doing this, the patient maintains better distance vision and increased near over a more traditional blended vision.

At a glance

• Experts stressed the importance of referring to it more as “blended vision” rather than “monovision,” as monovision tends to have a negative connotation.
• Ideal patient age may be in the 40s to early 50s.
• A contact lens trial may be helpful to simulate for patients what their vision will be like after this procedure.

About the doctors

Brandon Baartman, MD
Vance Thompson Vision
Sioux Falls, South Dakota

Lance Kugler, MD, PCEO
Kugler Vision
Omaha, Nebraska

Luke Rebenitsch, MD
ClearSight Center
Oklahoma City

Relevant financial interests

Baartman
: None
Kugler: None
Rebenitsch: Carl Zeiss Meditec

Contact information

Baartman
: brandon.baartman@vancethompsonvision.com
Kugler: lkugler@kuglervision.com
Rebenitsch: Dr.Luke@ClearSight.com

‘Blended vision’ for presbyopia patients ‘Blended vision’ for presbyopia patients
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