- Age-related macular degeneration (AMD) is a condition that gradually leads to the loss of central vision due to damage to the macula, the central region of the retina.
- There is a lack of effective treatments for advanced AMD, resulting in a lower quality of life and a reduced ability to perform daily activities.
- Implantable devices, including sets of lenses that function as a miniaturized telescope with the cornea, have been explored as a potential treatment.
- A small retrospective study recently showed that the smaller-incision new-generation implantable miniature telescope (SING IMT), an implantable tiny telescope, safely improved both near and distance visual activity.
It is estimated that about 20 million people in the United States have some form of age-related macular degeneration (AMD), a condition that causes central vision loss.
Previous
This first-generation implant has been described as cost-effective and compatible with other procedures such as cataract surgery. It has been approved for use in individuals aged 65 years and older with advanced AMD.
A second generation of this prosthetic developed by Samsara Vision, Inc., called the smaller-incision new-generation implantable miniature telescope (SING IMT), is designed to reduce the complexity of the surgical process, improve safety, and increase the speed of recovery.
A recent three-month study suggests that the SING-IMT is safe and improves distance and near visual in people with advanced AMD as well as resulting in lower levels of surgical trauma than its predecessor.
SING-IMT has not yet been approved by the Food and Drug Administration (FDA).
Dr. Edward Wood, a vitreoretinal surgeon with Austin Retina Associates in Texas who was not involved in the study, said the new technology shows promise.
“[This study evaluating the impact of the SING IMT showed] that at postoperative month three, 70.83% of patients gained ≥ 2 lines of visual acuity on the eye chart, 58.33% gained ≥ 3 lines, and 25.00% gained ≥ 4 lines of corrected distance visual acuity. Near visual acuity improved as well,” Wood told Medical News Today.
“Postoperative changes to the cornea (including changes to the endothelial cell layer) were comparable to those seen in modern cataract surgery. Overall, this trial showed that the SING IMT appeared to be safe and effective as a low-vision rehabilitation aid in patients with moderate to profound vision loss due to advanced AMD.”
— Dr. Edward Wood, vitreoretinal surgeon
The retina is the innermost layer of the eye, made up of photoreceptors that convert light into nerve impulses.
The macula is the central part of the retina and is involved in sharp, straight vision, also known as central vision.
The damage to the cells in the macula, known as macular degeneration, causes a gradual loss of central vision, impairing the ability to view fine details.
Age-related macular degeneration is the
AMD hinders the performance of daily activities, such as reading and driving, and is associated with a decline in quality of life.
Wet vs. dry AMD
AMD can be categorized as either wet or dry AMD.
While therapeutics are available for the treatment of early-stage AMD, there is a lack of interventions for people with advanced AMD.
There are also ongoing efforts to develop interventions to regenerate the cells in the macula that are lost due to macular degeneration. However, these interventions are still in the clinical trial phase and are years away from clinical use.
Currently, nonsurgical options for individuals with AMD include spectacles and magnifiers. However, using these aids requires individuals with AMD to get accustomed to hand or head movements to scan the visual field.
An alternative to these optical aids includes surgery to implant optics that are more intuitive to use and can attenuate the deficits in vision associated with AMD.
One such technology is the implantable miniaturized telescope (IMT), which uses a combination of lenses that function as a tiny Galilean telescope.
This implantable telescope consists of an objective biconvex lens that converges light rays from the object to form an image and another biconcave lens called the eyepiece that projects this image to the eye. These lenses are sealed to prevent exposure to fluids in the eye.
This miniaturized telescope helps to project light to the healthier regions of the retina and form a 2.2 to 2.7 times magnified image of the central visual field.
The other unoperated eye provides information about the peripheral visual field.
The first-generation IMT required an incision of 10-12 mm for implantation.
A clinical trial
The second generation of this prosthetic, the smaller-incision new-generation implantable miniature telescope (SING IMT), was developed to reduce surgical complexity and improve safety while retaining the same magnification as its predecessor.
Specifically, the implantation of the SING IMT requires fewer sutures and a smaller incision of 6-8 mm. The ease of implantation and reduced surgical complexity can reduce trauma during surgery and the recovery time after the operation.
“The smaller incision next-generation implantable miniature telescope (SING IMT) is a special lens that goes inside the eye to improve the visual experience for patients with bilateral moderate to profound central vision impairment due to advanced age-related macular degeneration. The patient undergoes cataract surgery followed by implantation of a special implantable miniature telescope (IMT) lens instead of one of the more commonly used intraocular lenses (IOLs).”
— Dr. Edward Wood, vitreoretinal surgeon
“It does not alone improve the health of the eye, but it is a sophisticated example of a low vision aid that is placed inside the eye, minimizing the burden of using other low vision aids,” Dr. Wood explained.
“The SING IMT is the second generation lens of its kind, with improvements including smaller size and subsequently more efficient surgery.”
The recent three-month study was done with people with moderate to advanced AMD in both eyes.
Researchers said it showed that the implantation of SING IMT prosthetic significantly improved far and near-visual acuity in the operated eye compared with before surgery.
Moreover, the study found that the damage caused to the inner layer of the cornea during the implantation of SING IMT was less severe than that due to the first-generation prosthetic.
This suggests that SING IMT may indeed reduce trauma during surgery, presumably due to the fewer sutures needed during surgery.