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Adjustable accommodating IOLs seem likely in near future
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A number of years ago, David Chang, MD, asked me to write a chapter for a book he was editing on the future of ophthalmology, including cataract and IOL surgery. In that chapter, I predicted the next disruptive technology in IOLs would be an adjustable accommodating IOL. We are now seeing a confluence of technology advances that make this seem a likely commercial product in the next few years.
The accommodating IOL will be a shape-changing lens, just like the human lens, and will be driven by natural accommodation using ciliary muscle power. Studies have shown that the ciliary muscle continues to contract with accommodation in most people throughout their life. This muscle activity delivers a force that can be harnessed to change the shape of an IOL centrally, increasing its dioptric power during accommodation.
One challenge has been retaining the elasticity of the capsular bag, which is reduced as the capsule undergoes fibrosis after surgery, resulting in increased stiffness. Keeping the anterior and posterior leaflets of the capsular bag apart appears capable of reducing capsular fibrosis, late capsular opacification and reducing loss of capsular elasticity. If so, a shape-changing in-the-bag accommodating IOL will be possible and preferred. If capsular elasticity cannot be retained long term after cataract surgery, we can still harness the power of the ciliary body to change an IOL’s shape by having a force-transmitting lever contact the ciliary muscle directly. In this style accommodating IOL, the optic would be captured in the capsular bag and one or more haptics would travel outside the capsular bag to contact the ciliary muscle directly.
Both style accommodating IOLs are in clinical trial and showing promise. We need adequate accommodative amplitude, at least 2 D and preferably 3 D, to allow a full range of vision from distance to near. It is also possible to imagine combining one or more other optical principles that increase depth of focus together to create a hybrid IOL. For example, small diameter aperture optics would work well in combination with an accommodating IOL, as might some extended depth of focus designs.
Once we have the accommodating IOL, we want our patient to have a refraction of plano sphere in every case. In order to achieve this outcome, we will need an adjustable IOL. Here again, both the Light Adjustable Lens (RxSight) and so-called femtosecond laser refractive index shaping show promise.
To allow these new-generation lenses to be implanted through a small astigmatism-neutral incision, they may need to be modular with one or more components implanted into the eye and then the final IOL constructed in the eye. This modular multipiece IOL technology is also in development and working well.
Finally, we need the delivery of these amazing next-generation technologies to be more patient friendly and economical. For that, I see us evolving to in-office bilateral same-day sequential cataract surgery, likely with a cataract removal technology that does not require ultrasound.
All of these advances come to us thanks to the amazing power of the innovation cycle, which leverages human and financial capital to our and our patients’ benefit. I look forward in 5 years to having one of my partners phacoaspirate my two cataracts and implant adjustable accommodating IOLs while performing same-day sequential surgery in our office. There will be no history and physical examination, no anesthesia standby, mild sublingual sedation and definitely no drops required after surgery. I will get a phone call the first day to confirm I am doing OK and see an ophthalmic technician, PA or optometrist in a week or two to see if I need an IOL power adjustment, which if needed can be performed at 4 weeks and repeated if necessary. For the cataract surgeon and patient, the future is bright indeed.
Disclosure: Lindstrom reports relevant financial disclosures with Foresight 6, AcuFocus, Johnson & Johnson Vision and RxSight.