Assessment of a novel pinhole supplementary implant for sulcus fixation in pseudophakic cadaver eyes

Abstract

PurposeTo evaluate a novel small-aperture supplementary implant that applies the principle of pinholes for management of irregular astigmatism, in postmortem human eyes.MethodsPseudophakic human cadaver eyes were imaged by anterior segment optical coherence tomography (AS-OCT) to assess position of the in-the-bag intraocular lens (IOL). Eyes were prepared as per the Miyake-Apple technique. Two versions of the supplementary implant (open-loop and tripod designs) were then inserted into the sulcus of each eye. Evaluations under AS-OCT and from anterior and posterior views of the anterior segment were used to assess IOL fixation, centration, tilt, and interlenticular distance (ILD). This experimental study has been conducted in John A. Moran Eye Center, University of Utah.ResultsNine eyes were selected, with various sizes, primary IOL materials/designs, and Soemmering's ring formation. The open-loop model exhibited a mild degree of decentration and tilt in 2 eyes with zonular dehiscence. Mild decentration and tilt of the tripod were observed in 4 eyes; in 1 additional eye it was centered but mildly tilted. Three eyes with zonular dehiscence had one of the closed loops of the tripod located posteriorly to the ciliary processes. In all cases, an ILD was observed between the lenses (open loop: 0.65±0.13 mm; tripod: 0.41±0.12 mm).ConclusionsIt is important to take into account anatomical aspects related to ciliary sulcus fixation of supplementary IOLs. Both designs evaluated, exhibited appropriate centration and ILD. The open-loop design had less risk of tilt in association with haptics protruding posteriorly through areas of zonular weakness.

Predictability of Refractive Outcome of a Small-Aperture Intraocular Lens in Eyes With Irregular Corneal Astigmatism

“…Compared to the add-on IOL XtraFocus (Morcher), which was especially designed for corneal irregularities and has no optical power, the IC-8 IOL can be placed directly in the capsular bag and can therefore be used during standard cataract surgery. 19 Its special design with an integrated smallaperture membrane for artificial pinhole effect reduces visual distortion, leading to a better visual perception. The extended depth of focus counteracts the currently difficult IOL power calculation in these eyes and still shows good visual results and patient satisfaction.…”

Small aperture IC-8 intraocular lens in cataract patients: achieving extended depth of focus through small aperture optics

“…With 4.25 D of corneal cylinder and an UNVA of 6/19 postoperatively, the patient was 'delighted' with the functional range of vision provided in their work as a truck driver. The advantage of the pin hole design in the treatment of irregular corneal astigmatism is also well documented with the XtraFocus pin hole IOL (Morcher, Stuttgart, Germany) [18][19][20][21]. The XtraFocus implant is a black, hydrophobic acrylic sulcus IOL that can be used in pseudophakic eyes, masks a greater area which may help with pupil abnormalities such as Aniridia and is translucent to infrared imaging.…”

A pinhole implant to correct postoperative residual refractive error in an RK cataract patient

“…32 Tsaousis et al hypothesized that the size of the central opening in Xtrafocus IOL may not be small enough to cause significant visual field loss. 33 Our results did not show any apparent changes in the visual field secondary to the pinhole lens implantation, with equal mean defect (MD) values of −4.3 dB on both eyes ( Fig. 5 ).…”