Implantable Macula Lenses for Patients with AMD—Focus on the Scharioth Macula Lens
Age-related macular degeneration (AMD) is the leading cause of visual impairment in the western world and its incidence is projected to increase: by 2020, 196 million people will have AMD, rising to 288 million in 2040. Although the use of anti-vascular endothelial growth factor (VEGF) intravitreal injections has transformed the management of neovascular (wet) AMD, a substantial proportion of patients do not respond to these therapies.2 In addition, there are no effective treatments for dry AMD, which accounts for 90% of all cases.3 Patients with AMD often develop significant visual impairment, which limits their ability to perform many activities such as reading, driving, recognizing facial features, watching television, and other social activities. This substantially reduces their quality of life and can lead to anxiety and depression.4,5 Low vision rehabilitation, involving external magnifying aids, can help patients to maximize their remaining vision and adapt to activities of daily living.6 However, external optical devices have limitations, particularly for reading,7 and elderly people can struggle to adapt to using magnifying aids, especially when high magnification is needed.
Intraocular implants offer an alternative approach for improving vision in patients with AMD by creating a magnified retinal image. A number of different approaches are available. The Implantable Miniature Telescope (IMT, VisionCare Ophthalmic Technologies, Saratoga, CA) is the only Food and Drug Administration–approved surgical device for AMD. It is a cylindrical device that is implanted in the capsular bag of one eye after removal of the natural lens and implantation of an intraocular lens (IOL). The eye implanted with the telescope provides magnified central vision, while the other eye provides peripheral vision. Its size (4.4 mm long, 3.6 mm in diameter) requires a 10–11 mm limbal or scleral tunnel incision and six to eight sutures to close the wound.8 A multicenter clinical trial (NCT03011554) is currently assessing the efficacy and safety of implanting IMT in pseudophakic patients. A limitation of this implant is that it reduces the field of vision to 22–25°.8
Other systems involve smaller incisions: the Intra-ocular Lens for Visually Impaired People (IOL-VIP, Soleko, London, UK), which is implanted into the capsular bag, and the iolAMD (London Eye Hospital Pharma, London, UK), which can be implanted in phakic or pseudophakic eyes, each comprise two small intraocular lenses to give a telescope effect. Evidence to date suggests that visual acuity improvements with the iolAMD are modest in comparison to those reported for the IOL-VIP.9,10 Another telescope approach, the Lipshitz Macular Implant (LMI, Optolight Vision Technology, Herzlia, Israel) is intended for phakic eyes and uses mirrors instead of lenses, but is expensive and carries the risk of glare effects.11 Optolight has also developed a version of the LMI that can be implanted in the sulcus as a piggy-back lens over an existing IOL, but no data is currently available on the efficacy and safety of this lens. The Fresnel Prism Intraocular Lens displaces the retinal image from a potentially damaged central macula to a healthier, peripheral part of the retina.12 All these techniques require complicated pre- and post-implantation visual rehabilitation programs, which can last for months.
The most recent advance is the Scharioth Macula Lens (SML, Medicontur, Geneva, Switzerland), a one-piece hydrophilic acrylic foldable “add-on” aspheric bifocal lens with a 1.5 mm diameter central portion that has a refractive power of +10 diopters. Therefore, it does not provide distance vision magnification but provides approximately 2x magnification for objects in a range of 10–15 cm from the eye. It is designed for pseudophakic eyes and is implanted into the ciliary sulcus in addition to the patient’s existing IOL through a minimum incision of 2.2 mm. This can be performed alongside conventional cataract surgery and posterior capsular IOL implantation or at a later date.13 Two studies, both involving eight patients, have shown that patients receiving the implant achieved good near visual acuity at a recommended reading distance of 15 cm.13,14 No corneal endothelial cell loss and no postoperative complications were reported. Further clinical studies (unpublished to date) involving nine centers in eight countries and 106 implanted eyes, have reported stable improvements in visual acuity at one month and high levels of patient satisfaction.15 Visual rehabilitation is needed but adaptability to these lenses has been good.
A study presented at the 2018 European Society of Cataract and Refractive Surgeons, which was held on September 22–26, 2018, in Vienna, Austria, assessed the quality of life of 26 patients with AMD implanted with the SML.16 After implantation of the lens, patients did not experience any change in distance vision, which was expected. However, 35% or them achieved normal reading vision, with a gain of at least three lines. Quality of life was assessed using the Vision Function Questionnaire, which comprises 25 questions about general health, vision, and difficulty with daily activities, as well as individual responses to vision problems. Patients demonstrated significant improvement, with an overall improvement of 28% on the questionnaire. Improvement was particularly marked in patients with legal blindness vision loss (48%), while people with low vision showed only a 16% improvement. Improvements were reported in parameters relating to general heath, vision, and daily activities. The lenses enabled patients to perform near-vision tasks that had been previously impossible, including shopping and working in the kitchen.16
The lead author, Niels Vesti Nielsen, MD, of Charlottenlund, Denmark, emphasized the importance of discussing expectations with the patient. It is also essential to provide precise information to the patient and help them in the learning process.16 “Professor Scharioth’s lens (SML, Medicontur) is an excellent new concept, overcoming the limitations, discomfort, and stigma attached to extended low vision aids,” Dr. Nielsen said. “It is a simple add-on IOL with bifocal design, with a central 1.5 mm optical zone of +10 D and optically neutral peripheral zone. It is easily implanted and explanted if needed.”17
Despite major advances in the treatment of AMD, patients with advanced disease still experience substantial vision loss. Implantation of intraocular lenses has shown clinically meaningful improvements in visual acuity and quality of life. To date, only short-term outcomes have been reported; larger, long-term studies are needed. It is also important to remember that success will depend on the commitment of the patient to visual rehabilitation programs. The latest data on the SML suggest that it may overcome the limitations of existing options and that it has demonstrated positive outcomes, giving hope to many patients with AMD and low vision.
References
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15. Medicontur. The Macula Lens. Available at: https://macula-lens.com/introduction/ (February 7, 2019).
16. Nielsen Niels V, Helgesen A, Muus G. Scharioth Macula Lens for AMD: Quality of Life Study. Presented at: European Society of Cataract and Refractive Surgeons meeting, Vienna, Austria, September 22–26, 2018.
17. Nielsen NV. Macula add-on lens improves quality of life for patients with AMD. 2018. Available at: www.healio.com/ophthalmology/refractive-surgery/news/online/%7B39f1a7c0-5d6f-43b3-accb-b273375b730e%7D/macula-add-on-lens-improves-quality-of-life-for-patients-with-amd (February 7, 2019).