Increasing the solutions for your cataract patients with RayOne EMV
While multifocal intraocular lenses (IOLs) are still a great option for some patients, the RayOne EMV lens broadens the range of options for cataract patients who want to increase their intermediate range of vision, and even for those with myopia who want to increase their near range of vision as well. This lens is particularly appealing for individuals not suitable for diffractive multifocal lenses or those who are not bothered by using a pair of glasses for the smallest print.
From my years of experience, I have found that a target of -1.0 diopter (D) with a standard monofocal lens does not result in high rates of patient satisfaction. They do not achieve adequate distance vision and intermediate vision is quite limited as they do not achieve a table- or arm-length range of reading vision. This makes the results we have seen with the RayOne EMV compelling, particularly with the intermediate and closer range of vision. I started using the RayOne EMV in the spring of 2021 and patients are very happy with the results. In general, they have an increased range of focus and tolerate the small degree of anisometropia without issues. The quality of vision reported is excellent.
Selecting the right patients
I continue to implant a range of premium IOLs, so I work with my patients to decide what is the best fit for their needs and expectations. In this regard, I consider two general categories of patients when making these decisions. First, there are the patients who are undergoing cataract surgery solely for visual impairment without other significant pathology. Then, there are patients with small amounts of other pathologies such as mild glaucoma, mild age-related macular degeneration (AMD), or those with up to 0.8D of corneal cylinder. I now routinely offer the RayOne EMV lens to the majority of my standard cataract patients, but I am increasingly comfortable considering this option in patients with these other mild pathologies. I find the lens is quite forgiving and thus increases the range of patients undergoing cataract surgery who are suitable candidates for a lens that increases their functional range of vision. When I started with the RayOne EMV, most of my patients had received a standard monofocal lens in the dominant eye and a RayOne EMV lens in the contralateral eye, which produced very good outcomes and patient satisfaction levels. This remains a very valid and worthwhile approach for patients coming in for second eye surgery or those who may be cost sensitive.
When starting with any new lens, I make sure that I am happy with my biometry and IOL power calculation, and that the A-constant has previously proved to be reliable. I utilise multiple formulas and make sure I countercheck them. I also check the corneal curvature on more than one piece of equipment.
I also tend to start on patients with myopia because that allows me to test my biometry and resulting refractions. I started targeting myopia at -2.0 D, with a goal of enhancing their near vision. I have also implanted RayOne EMV in patients targeting what I call ‘indoor myopia’ at -1.0 D and -2.0 D, including two wheelchair-bound patients and one patient who works indoors in hospitality who wanted to have indoor vision and did not drive very often. I am now aiming for -0.75 D and -1.75 D for my ‘indoor vision’ patients. Considering these patient types for a lens like RayOne EMV allows surgeons to test different IOL power selections based on the patient’s biometry and their ability to blend vision if this is a new management strategy in your practice. These initial patients were very happy with their outcomes, and they now only require glasses for distance vision when they are driving or walking around. That is a significant improvement that compares superior to standard monofocal outcomes with a target of -1.0 D, which often results in visual outcomes that are not ideal for any activity, leaving patients unhappy.
In practice, I tend to implant EMV in the non-dominant eye with a target of up to -1D and do not perform monovision trials with contact lenses at this level. Specifically, I choose a target of -0.50 D, -0.70 D, or -0.90 D depending on my assessment of patient tolerance and preference. I know some colleagues who suggest increasing the degree of myopia in the non-dominant eye to -1.25 D or -1.50 D, which does increase near vision in some patients. However, on the odd occasion when the outcome is more myopic than planned, you run the risk of diminishing distance visual acuity further, which hyperopic patients in particular find difficult. With a goal of -1.5 D or -1.75 D, an initial monovision trial might be warranted. Higher myopia targets increase the risk of patient dissatisfaction which can prove problematic, especially if subsequent revision or laser top-up procedures are not possible due to availability or cost concerns.
With a goal of just under -1.0 D (-0.8 D or -0.9 D) patient expectations need to be set ahead of time about potential distance blur and the reality that visual outcomes should not be compared between the two eyes. With these expectations communicated prior to surgery, patients understand that the non-dominant eye may demonstrate some degree of distance blur. Another way of adequately explaining this to patients is that one eye will be predominantly for outdoor vision and one with be for indoor vision. Again, surgeons should exercise caution in aiming for higher degrees of myopia in the non-dominant eye. This strategy may be satisfactory if you commonly offer a subsequent laser vision correction option in your clinic. Otherwise, with a myopic goal that does not extend beyond -1.0 D, patients should be consistently happy with their outcomes but with particular care with counselling if the non-dominant eye is operated on first.
Patients who received RayOne EMV with a target of between -0.6 D to -0.9 D have generally achieved very good intermediate vision at 1 to 2m, consistently between 6/9 and 6/12 Snellen, and some with quite good arm’s length reading vision as well. I have recently been offering the EMV targeting emmetropia in the dominant eye and adjusting the power of the second eye to blend in from the extended first eye range. Patients are satisfied as they can see the range of the dominant eye and appreciate the intermediate range starting point provided by the non-dominant eye.
In terms of nighttime vision and dysphotopsia, I have not yet seen any problems in my patients who received RayOne EMV. I nevertheless counsel all RayOne EMV patients because, with a target of about -1.0 D to -0.75 D, patients may notice distance blur if they cover their dominant emmetropic eye. Therefore, I tell my patients that they may need a pair of driving glasses for driving at night, as well as a pair of computer or reading glasses. I do not promise complete spectacle independence, just a high degree of spectacle independence particularly for indoors and intermediate vision. I will look forward to tracking outcomes with Rayner’s RayPRO platform that allows patients to report satisfaction and functional vision over a period of three years, as we gain more experience with this IOL in the future.