THE IC-8 APTHERA ASPHERIC MONOFOCAL INTRAOCULAR lens (IOL) from Bausch + Lomb serves a unique set of patients in a way that no other implant currently does, so surgeons need to be familiar with how to succeed with it.

Developed by AcuFocus, the IC-8 Apthera IOL was approved by the FDA in July 2022 as the first and only small-aperture nontoric extended-depth-of-focus (EDOF) IOL for cataract patients who have as much as 1.5D of corneal astigmatism and wish to address presbyopia at the same time. The IOL is a hydrophobic, acrylic, single-piece lens implant. In January 2023, Bausch + Lomb acquired AcuFocus.

In this article, I’ll share my experience with this new wavefront-filtering lens and then provide additional perspectives from other surgeons who have experiences with it as well.

Optical Mask

Most surgeons will find the IC-8 Apthera similar to many other lenses they use, except for the notable difference of an optical mask, referred to as the FilterRing component with a small central aperture, built into the lens material itself. The lens has an optic diameter of 6.0 mm and an overall diameter of 12.5 mm. The FilterRing component has an outer diameter of 3.23 mm and an aperture diameter of 1.36 mm.

This design allows the majority of the light coming into the eye to enter through the center of the implant. Because of the small aperture design, the IC-8 Apthera can correct mild to moderate levels of astigmatism and decrease the blur circle on the retina. This allows patients not only to have well-focused light for the intended range of focus but also a reasonable range of focus on both sides of the focal point of the lens.

The lens is designed for unilateral implantation in patients with as much as 1.5D of corneal astigmatism in the implanted eye.

The FDA Study

In an FDA study, the IC-8 Apthera was implanted in the second eye after the patient received a monofocal or a monofocal toric lens in the first eye. The first eye was targeted for distance vision, and the second eye was targeted for about -0.75D.

This arrangement of having the first eye, which was the dominant eye in about 90% of the cases, corrected for distance and the second eye for -0.75D allowed the majority of the patients with the nondominant eye to achieve J2 vision correction and to have reasonable distance vision in the eye as well. Binocularly, patients had excellent performance, and satisfaction was high in this population.

Two Patient Types

In general, surgeons can consider using a small-aperture design in 2 types of patients: those with irregular eyes and those in whom identifying the axis is difficult. For the first population, consider using the IC-8 Apthera for patients with keratoconus with milder degrees of astigmatism and perhaps those with previous radial keratotomy (RK), as long as the patient has a clear corneal medium centrally in the affected eye. I have implanted the lens in these patient types and even implanted it bilaterally in some of these patients with very good results. So while the IC-8 Apthera has been tested for unilateral implantation in eyes with regular astigmatism, clearly it has value for bilateral implantation in those who have more irregular eyes.

The second population where the IC-8 Apthera could fit is patients who want a mild degree of monovision and have low astigmatism where it may be hard to identify the axis. No doubt you’ve encountered patients with enough astigmatism to correct with an implant (perhaps 1D), but with varying axis measurements. With the IC-8 Apthera, you can break the rule of axis alignment and implant the lens wherever you like, with the assurance that you will have a good correction. You simply need to get the lens within about three-quarters of the desired spherical equivalent, and you will more or less hit your target.

Selection Considerations

When selecting candidates for the IC-8 Apthera, choose patients whose eyes dilate to about 7.0 mm. The reason is that the FilterRing component will obscure the retina. Because it’s difficult to do a retinal exam by looking only through the central aperture, you want to look at the retina peripheral to the FilterRing. With adequate dilation, even retina specialists agree that the examination is relatively unhindered.

In addition, having patients with ample dilation is important if a patient develops posterior-capsule opacity and needs a YAG laser capsulotomy. Directing YAG laser pulses through the FilterRing will damage the lens. You’ll want to direct the YAG laser pulses peripheral to the FilterRing using an inverted “U” or Omega pattern.

Also, exercise caution with patients who have significant ocular surface disease causing surface disruption in the central part of the cornea. The FilterRing does not improve vision when there is significant central opacity. In fact, implanting the lens could make things worse if you force light to focus through a particularly irregular central cornea.

Surgically, the lens requires a 3.2 mm incision—larger than most foldable single-piece lens implants used today. With continued revision, this need may become less.

As noted above, 2 other surgeons who have experience with this lens have provided their perspectives.

• William F. Wiley, MD, Medical Director of the Cleveland Eye Clinic

Our results show that the IC-8 Apthera is very effective for improving near vision in 1 eye. More specifically, the lens can be used with patients who have been accustomed to monovision in the past, are considering monovision, or who have irregular astigmatism.

One patient population in whom we’ve used this lens is experienced contact lens wearers who now want pseudophakic monovision to mimic their contact lens monovision. This lens provides them with a similar experience.

Patients with contact lens monovision still retain a bit of accommodation, so there is some forgiveness. When patients move to traditional pseudophakic monovision, that accommodation goes away, so hitting the targets becomes critical. However, the IC-8 Apthera provides a softer landing in the near eye and extends the depth of focus, making it more similar to what patients have experienced with contact lens monovision or phakic monovision.

We’ve also used the lens off-label in patients who have had radial keratotomy (RK) or other forms of irregular astigmatism, such as keratoconus or mild keratectasia. The IC-8 Apthera pinhole effect can act as a pinhole occluder in the lane, where it blocks the irregular light and lets the clear light through. We’ve seen some patients have success in improving not only uncorrected visual acuity but best corrected visual acuity through the aperture effect.

Moreover, some RK patients have a diurnal fluctuation, in which refraction changes throughout the day. The aperture optic mutes that effect, providing more stable vision throughout the day. Furthermore, some of those patients had some irregular astigmatism with glare and halo; the lens can block some of that irregularity.

We’ve also seen the IC-8 Apthera perform well for patients in whom it’s challenging to predict where the astigmatism axis lies or how much to correct. When there is up to 1.5D of astigmatism, it performs the same as if there were no astigmatism. Functionally, the IC-8 Apthera can correct astigmatism without using a toric lens.

As with any single-piece monofocal lens, you need to ensure it’s centered on the visual axis; you don’t want to use the IC-8 Apthera in a patient in whom decentration could occur. You also won’t want to use this lens for patients who have central visual pathway opacity, such as a central scar or many vitreous floaters. Similarly, it’s best to avoid this lens in patients who have dry eye surface disorder.

You’ll also want to use care in implanting the lens for patients who might need retina surgery—trying to perform retina surgery through the aperture is not ideal.

• Doug Wallin, OD, Vance Thompson Vision, Sioux Falls, SD

In our practice, our initial goal was to use the IC-8 Apthera, in some cases off-label, for patients in whom we normally wouldn’t use an advanced optic lens because they had significant optical aberrations in their corneas, perhaps from previous corneal surgeries, such as RK or LASIK. Typically we would steer such a patient away from the most common advanced lens we would use, which is a diffractive multifocal lens. In those patients, we saw success with the IC-8 Apthera’s ability to extend the depth of field over a fairly wide range.

Before the IC-8 Apthera, we would implant a monofocal lens or a monofocal with light adjustability in a cataract patient who had undergone a previous surgery, such as RK or LASIK. If we didn’t hit the target, the patient might have to wear glasses to get the best vision. Alternately, we might consider doing a corneal enhancement, which might not be optimal or predictable in these patients. Now, we have the option to use the IC-8 Apthera.

We’ve also used the lens with patients who have had no previous corneal surgeries. We’ve enjoyed pairing the IC-8 Apthera with enhanced monofocal lenses that provide a little extra depth of focus. Keeping patients slightly on the myopic side to move the defocus curve slightly into the nearsighted side is where the Apthera shines.

The FDA clinical trial data show that there’s just shy of about 2D of extended depth of focus with Apthera. That puts patients at good intermediate vision and decent near vision. That’s where that target becomes so important because, if you can move patients slightly on the myopic side, then you extend that 2D range, which improves near vision.

Compared with other advanced implants, I’ve been impressed with the IC-8 Apthera’s image quality. With the FilterRing, you eliminate some of the peripheral light rays that could impair image quality.

The FDA study looked at contrast sensitivity, both mesopic and photopic. When the control group monofocal was compared to the Apthera, both mesopic and photopic contrast sensitivity was very similar. You’re getting good contrast sensitivity with an implant that is also giving you that enhanced intermediate and near vision. You don’t find that with every lens. ■

Dr. Hovanesian is in practice at Harvard Eye Associates in Laguna Hills, CA, and is the founder of MDbackline and Research InSight.

Disclosures
Dr. Hovanesian is a consultant for AcuFocus and Bausch + Lomb.
Dr. Wiley is a consultant for Bausch + Lomb.
Dr. Wallin has no relevant disclosures.