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  • Cataract/Anterior Segment

    Review of: Evaluation of a new device to treat negative dysphotopsia

    Roop P, Nayak S, Kittur A, et al. Journal of Cataract & Refractive Surgery, February 2024

    A prospective interventional study evaluated a prototype of a device designed to be implanted in the sulcus to help treat the symptoms of negative dysphotopsia (ND).

    Study Design

    This was a prospective interventional cohort study conducted at tertiary eye centers in India. The ND ring implant is made of a proprietary hybrid hydrophilic acrylic and measures 12.8 mm with a 5-mm inner diameter. The device is 0.25 mm thick and has a bi-concave cross-section that diverges the light on its inner edge, which is then distributed to the area of ND shadow. It is injected into the anterior chamber through a 2.2-mm incision using a disposable injector and cartridge that is provided with it. Thirty-eight patients with ND were asked if they wanted to be fitted with the ND ring; 15 opted to have the ring implanted in the eye with ND (treatment group), 7 opted to have the ring implanted in the fellow eye while they underwent cataract surgery (prophylactic group), and the remaining patients opted to not be fitted with the ring. Efficacy and safety outcomes were reviewed at several time points following ND ring implantation.

    Outcomes

    Complete resolution of ND symptoms was seen in 93% of the patients in the treatment group, and no patients who underwent prophylactic implantation reported ND in the fellow eye. Investigators did not note any significant anterior segment inflammation, and iris rubbing, chafing, and transillumination defects were not seen until the 1-year follow-up visit. No subjective changes in refraction were noted in either group.

    Limitations

    There were several limitations with this study. There was no quantitative assessment of the ND, and the study population was relatively small. As well, changes over time in pupil size, capsule fibrosis, and capsulorrhexis capsule size were not discussed.

    Clinical Significance

    It would be valuable to have a solution to a visually significant and sometimes unpredictable outcome of cataract surgery that any surgeon can encounter. Patients who develop ND are often frustrated with the lack of ease or feasibility and reliability of resolving the problem. This experimental device has a unique mechanism of action that can potentially address the problem of the peripheral retinal shadow between the light rays refracted by the nasal IOL optic and those that miss the optic. This could overcome the need for more complex IOL exchange techniques that require skilled surgical maneuvers. Further evaluation will be needed before the ND ring can be submitted for approval by regulatory agencies.

    Financial disclosures: Dr. Amal Alwreikat discloses no financial relationships.