Study: Iris Implant Safe, Effective Aniridia Treatment

Severe ocular trauma that results from blunt or penetrating injuries often result in damage to several anatomical structures. For major traumas, when large aniridic defects are seen along with traumatic cataracts or aphakia that require intraocular lens (IOL) implantation—an iris prosthesis can be safely and effectively utilized, according to a study published recently in BMC Ophthalmology. 

A retrospective observational case series indicated that the combination of an iris prosthesis and an intraocular lens can lead to improved monocular corrected distance visual acuity (CDVA), reduced glare sensitivity and pupil area, and decreased endothelial cell density (ECD), as seen at a 5-month follow-up with patients.

The foldable, custom-made iris prosthesis, can be implanted without fixation sutures. Surgeons can use an IOL injector to implant it into the posterior chamber. It received FDA approval in 2018 for the treatment of vision and cosmetic problems stemming from aniridia in both adult and pediatric patients. 

The research looked into 7 years worth of combined IOL and iris prosthesis surgeries from one surgeon. It took into account 59 eyes of 56 adult patients who had cataracts, or aphakia, and large aniridic defects. Fifty-three of the 59 eyes were post-traumatic upon referral. The patients underwent cataract surgery with either implantation of a one-piece hydrophilic acrylic IOL in the capsular bag or suture of a polymethylmethacrylate IOL to the sclera. They then received artificial iris implants through an incision into the ciliary sulcus. 

Before surgery and at the five-month follow-up, the physicians assessed the patients’ intraocular pressure (IOP), CDVA using optotypes, photopic and mesopic contrast sensitivity (CS) using the Pelli-Robson chart, ECD, and reduction of pupil area and centration of iris prosthesis. Patients also rated their sensitivity to glare from 1 to 10 on a visual analog scale.

Results from the surgery showed that 32 patients experienced at least an increase of 0.2 logMAR in their monocular CDVA (P <.0001). CDVA improved in 41 eyes, was approximately the same in 2 eyes, and worsened in 13 eyes.The patients’ pupil area decreased 79.30%, from 51.27 mm² to 8.81 mm² (P <.0001). Their edian ECD decreased from 2646.0 mm² to 2497.5 mm² (P =.007) andmedian glare decreased from 9.0 to 4.0 (P <.0001). 

In the 36 eyes that photopic contrast sensitivity could be recorded, the median increased from 0.9 to 1.35 (P =.008). Under mesopic light conditions with glare, contrast sensitivity was approximately the same (P =.844). The median IOP remained at 15.0 mm Hg (P =.881).

Factors for limited increase of postoperative visual outcomes included central corneal scarring and clouding, dislocation of the iris pro, and persistent macular edema,” the researchers wrote.

Four eyes experienced device dislocation, and 2 of the eyes developed glaucoma. One of the 59 eyes in the study developed chronic irritation and persistent macular edema and corneal decompensation, and the artificial eye was explanted.

The implants significantly decreased glare, eliminated severe photophobia and corrected refractive disorders, the researchers concluded. They added that their approach offers surgeons an option to treat partial or total aniridia as well as aphakia in a single surgery with very few severe adverse events.

References

Mayer C, Hoffmann A, Prahs P, et al. Functional outcomes after combined iris and intraocular lens implantation in various iris and lens defects. BMC Ophthalmol. 2020;20:370. doi: 10.1186/s12886-020-01621-8