Implantable miniature telescopes (IMTs), as well as various specialized intraocular lenses (IOLs), can significantly improve vision and daily activities for patients with age-related macular degeneration (AMD), according to a review published in Eye. Devices, such as the 8 reviewed in the publication, consider head motion, vestibular ocular reflex adaptation, and monocular depth perception, giving them an edge over external aids, according to the report.
Altogether, the investigators reviewed research into:
• The IOL for Visually Impaired People (IOL-VIP, LensSpecial) system: A double IOL implant consisting of a biconcave high-minus-power IOL in the capsular bag and a biconvex high-plus-power IOL in the anterior chamber. These technologies work with the cornea to create an intraocular Galilean telescope with 1.3 times magnification for distance.
• The IOL-AMD (Enhanced Vision): A system that uses the principle of a Galilean telescope by creating a pair of 3 mm corneal incisions and implanting 1 high-negative and 1 high-positive soft hydrophobic IOL into capsular bag and ciliary sulcus, respectively. This produces a 1.25 to 1.3 times magnification, with a visual field reduction of approximately 30%.
• EyeMax Mono (SharpView Ophthalmology): A wavefront optimized, single-piece, soft, hydrophobic 6 to 13 mm acrylic IOL that provides magnification from 1.1 to 1.2 times by allowing patients with single or multiple preferred retinal loci (PRL) to gain optimum benefit from the most functional areas of the macula.
• IMT Prosthetics (Samsara Vision): Combined with corneal power, this device (designed to be implanted in only 1 eye) enlarges objects in the central visual field. Meanwhile, the contralateral eye compensates for peripheral vision. Of note, a 2-year study of 217 patients with AMD revealed a 3-line or more increase in best-corrected visual acuity (BCVA) in 59.5% of 173 telescope-implanted eyes compared with 10.3% of 174 fellow eyes. The IMT is the “first and only FDA-approved implantable medical device demonstrated to improve vision and quality of life in qualified individuals with advanced AMD,” the researchers report.
• Smaller-Incision New-Generation (SING) IMT (Samsara Vision): Similar in magnification range to the IMT prosthetic, this lens allows for a smaller incision size (6.5 mm) which can reduce surgical trauma, induced astigmatism, and the number of sutures required.
• Scharioth Macula Lens (Medicontur): A single-piece lens designed for patients with advanced AMD, it has the advantage of enhancing near vision without negatively affecting peripheral vision. This lens can be implanted during routine in-the-bag posterior chamber IOL implantation, or years following cataract surgery.
• LENTIS MAX (Teleon Surgical BV): This aspheric, biconvex IOL has 2 sections with a total additional power of +8 diopters (D). A 4-year follow-up of 11 patients revealed functional gains in 100% of the study group in the first 3 to 6 months following cataract surgery, and improved quality of life in 10 patients.
• Lipschitz macular implant (LMI, OptoLight Vision Technology): Dielectric coatings that act as mirrors produce 2.5 times magnified image on the central retina and regular-sized image on the periphery. An analysis of 6 eyes of 4 patients revealed a mean distance acuity gain of 3.66 lines in patients with this implant, and a mean increase in the Early Treatment Diabetic Retinopathy Study (ETDRS) score for near acuity of 50.83 logMAR, according to the review. However, all patients included in the analysis experienced postoperative glare.
All of these devices have demonstrated the ability to improve vision and quality of life in individuals with AMD, but few head-to-head comparisons have been made between the devices and most sample sizes have been small.
However, the IMT, is the exception with evaluation from more than 200 patients and 5 years worth of follow-up data. That research shows that long-term corneal endothelial cell loss, a potential concern for patients with the implant, are comparable to rates from routine cataract surgery, and that it could be reduced even further with the updated SING version of the device.
Evidence-based decisions may be limited by the absence of validated visual function or patient reported outcome measures for patients with AMD. These devices may not produce optimal outcomes for patients with very severe disease and advanced retinal degeneration.
“[T]here are multiple intraocular vision-improving devices available for intervention in patients with advanced AMD,” according to the researchers. “While these advances in technology can offer hope to many patients, it is difficult to predict how well the results in the clinical literature will generalize to actual practice.”
Borkenstein AF, Borkenstein E-M, Augustin AJ. Implantable vision-enhancing devices and postoperative rehabilitation in advanced age-related macular degeneration. Eye. Published online July 22, 2022. doi:10.1038/s41433-022-02179-z