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Conquering the holy grail: New treatments for presbyopia on horizon
A better understanding of how the presbyopic eye works has opened the door to new approaches to treatment.
Many premium surgeons are still trying to seek and conquer the holy grail of presbyopia treatment. Despite the many advances in presbyopia correction, we have not had a better understanding of the true model of what happens to the eye during presbyopia in terms of extralenticular components until recent evidence was published by Croft’s and Goldberg’s groups. Corneal and IOL approaches have been the predominant methods of surgical presbyopia correction, but scleral approaches are gaining momentum based on this new research.
Corneal approaches
Aside from the traditional monovision approach with LASIK, PRK and/or monofocal IOLs, there have been limited new options on the cornea for presbyopia correction. Multifocal ablation patterns of the past created intolerable aberrations for patients until the CE approval of the Supracor technique (Bausch + Lomb Technolas). Supracor is an optimized presbyopic algorithm with minimal induced corneal aberration error, but unfortunately, this technique is not available in the United States yet. In the hyperopia cohort, 87% of patients achieved a minimum of J2 and 20/25 binocularly at 6 months postoperatively. Only two out of 46 eyes in this small cohort lost one line of best corrected distance visual acuity at 6 months.
Corneal inlays are another popular approach to presbyopia correction, and the Kamra inlay (AcuFocus) is the first presbyopia-correcting inlay submitted to the U.S. Food and Drug Administration for approval. The current state-of-the-art procedure of inlay implantation is into a femtosecond laser-created lamellar pocket between 200 µm to 250 µm deep. Mean uncorrected near visual acuity in more than 20,000 procedures worldwide is 20/25 (J1 to J2), and mean uncorrected distance visual acuity is 20/25; only 1.03% lost two or more lines of best corrected distance visual acuity at 24 months. Interestingly, the removal rate was exceedingly low at 1.2%. There are other inlays in FDA trials as well, such as the Flexivue Microlens (Presbia) and the Raindrop (ReVision Optics).
IOL approaches
The newest player to the presbyopia-correcting IOL arena is the Trulign (Bausch + Lomb), currently FDA approved and available to correct cylinder power at the corneal plane up to 2 D. The Trulign offers a broader range of vision, especially for intermediate tasks such as laptops, computers, cell phones and tablets. The Trulign is the only toric IOL in its class that can be called a “toric with benefits” while still filling the needs of presbyopia visual function. A unique feature of this toric design is its extreme rotational stability, with 96.1% having rotation of 5° or less at 6 months vs. prior assessment. Trulign is the only toric in its class with an FDA indication of improved uncorrected near, intermediate and distance vision. Toric multifocal IOL technology is still not available in the U.S.
Scleral approaches
The Helmholtz lenticular theory of accommodation has stood the test of time while various technological advances have allowed us to understand the relationship among the ciliary body, vitreous, zonules and anterior hyaloid face as they apply to current scleral-based presbyopia surgical options.
The first of these two technologies is the PresView Scleral Implant (Refocus Group), which is currently in phase 3 of the FDA approval process. The mean age of patients in the 645 eye cohort (330 primary eyes, 315 fellow eyes) was 54.3 years, with 73% of patients rating excellent-acceptable bilateral intermediate computer vision at 24 months postoperatively vs. 24% preoperatively. The scleral implant works by vaulting the sclera over the ciliary muscles, increasing the circumlental space and affecting zonular tension on the lens. The second technology in this category is the LaserACE system (ACE Vision Group). The system uses the VisioLite Er:YAG laser to ablate 600 µm laser spots in the sclera, which are presumed to facilitate ciliary muscle contraction by decreasing scleral resistive forces, based on recent publications studying extralenticular components of presbyopia. Current clinical trials are being performed outside the United States. Data presented at the 2013 European Society of Cataract and Refractive Surgeons meeting showed an average of four lines of improvement at 12 months, with an average increase in accommodative amplitude of 1.5 D and 90% patient satisfaction ratings.
The exciting news is we continue to get closer to that esteemed holy grail known as presbyopia correction. Our most recent understanding in how the eye works in presbyopia will pave the way for other technologies to evolve in the continual hunt for the grail.
Stay tuned for next month’s Premium Channel column, Femtosecond laser technology a decade later: It seems like yesterday.