Biomedical subjects
Publications and source records attributed to Michael E Snyder.
Two patients developed a hyperopic shift following uneventful phacoemulsification with implantation of a Collamer plate-haptic intraocular lens (Staar Surgical) in the capsular bag. Posterior bowing of the IOL was corrected by IOL exchange, achieving near emmetropia.
A new modification of the Siepser sliding knot technique allows the surgeon to create a locking knot when performing iris reconstruction or intraocular lens fixation to the iris.
Iris reconstruction in cases of iridocorneal endothelial (ICE) syndrome is extremely challenging because of the nature of the iris tissue, which is typically friable and poorly suited to suture repair. Reconstruction in such cases often requires artificial iris implantation. This report illustrates cataract extraction and iris reconstruction with a multipiece endocapsular iris prosthesis that can be inserted through a small incision. Maintenance of a small incision size is a distinct advantage when glaucoma is coexistent in patients with ICE syndrome. It also demonstrates the presence of an ICE membrane over the anterior capsule and the importance of recognizing this membrane rather than confusing it with the anterior capsule when performing the capsulorhexis.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A 54-year-old woman with leukocoria from a white cataract requested evaluation for the undesired cosmetic appearance of her blind right eye. The eye was hypotonous from chronic total retinal detachment, and the lens appeared loose and partially resorbed. A solid, black poly(methyl methacrylate) intraocular prosthesis was placed in the phakic posterior chamber and sutured into the ciliary sulcus, leaving the lens undisturbed. The patient achieved excellent cosmesis and a significant improvement in self-image.
We developed and evaluated a method of visualizing vitreous gel in the anterior segment. In this study, 0.2 mL of injectable triamcinolone (Kenalog) 40 mg/mL was captured in a 5 microm filter and rinsed with 2 mL of balanced salt solution (BSS). It was then resuspended in 5 mL of BSS and recaptured to thoroughly remove the preservative. The Kenalog particles were ultimately resuspended in 2 mL of BSS and injected into the anterior chamber through a 27-gauge cannula. Kenalog particles were trapped on and within the vitreous gel, making it clearly visible. The visualization provided direct observation of vitreous behavior in various experimental settings and assisted surgeons intraoperatively in the identification and removal of vitreous in the anterior segment.
PURPOSE: To evaluate the results of implantation of a modified capsular tension ring (MCTR) and a posterior chamber intraocular lens (PC IOL) in patients with congenitally subluxated crystalline lenses. SETTING: Cincinnati Eye Institute, Cincinnati, Ohio, USA. METHODS: Ninety eyes of 57 patients with congenital loss of zonular support (Weill-Marchesani syndrome, idiopathic ectopia lentis, and Marfan's syndrome) had phacoemulsification with PC IOL and MCTR implantation. The preoperative examination included best corrected visual acuity (BCVA) and the presence or absence of phacodonesis, lens decentration, and vitreous prolapse. The postoperative evaluation included BCVA and the presence or absence of pseudophacodonesis, PC IOL centration, and posterior capsule opacification (PCO). RESULTS: At the last postoperative examination, the BCVA was 20/40 or better in 80 eyes (88.9%); 1 eye (1.1%) lost 1 line of acuity. Preoperatively, 18 eyes (20%) had phacodonesis; 1 eye had postoperative pseudophacodonesis. Decentration before surgery was present in 86 eyes (95.6%); 6 eyes (6.7%) developed late symptomatic PC IOL decentration a median of 17.84 months +/- 10.73 (SD) after surgery. Other complications were increased intraocular pressure (2.2%), persistent iritis (3.3%), broken suture (10.0%), retinal detachment (1.1%), and PCO (20.0%). CONCLUSIONS: Use of the MCTR resulted in centration of the capsular bag and PC IOL in 90 eyes with congenitally subluxated crystalline lenses. Fixation of a 9-0 polypropylene suture is recommended to decrease the risk for late suture breakage.
The anatomy of the capsules and zonules varies with each patient, particularly in the zonule-free zone. We present a case in which indocyanine green dye highlighted the anterior lens capsule and centrally encroaching zonular fibers within a 2.0 mm zonule-free zone. We suggest technique modifications to reduce the risk for capsule extensions and related complications.
PURPOSE: To report the histopathologic and ultrastructural features of three cases of interlenticular opacification (ILO) between piggyback intraocular lenses. DESIGN: Interventional case series with clinicopathologic correlation. METHODS: Three pairs of acrylic piggyback lenses were explanted due to decrease in visual acuity associated with ILO. Lenses were evaluated with gross and light microscopic examinations in all cases. The anterior lens in one case was examined with scanning electron microscopy and energy dispersive x-ray spectroscopy. RESULTS: The material opacifying the interlenticular space was composed mostly of retained/regenerative cortical material in all cases. From the peripheral interface towards the central interface, the opacifying material changed as the interlenticular space was progressively narrower. The material attached to the peripheral interface, where the interlenticular space was wider, was very thick. At the midperipheral interface, the thick cortical material was broken into multiple globules due to liquefactive degeneration. At the paracentral zone, compression of the globules formed a flat, compact layer of an amorphous material. At the central interface (contact zone), almost no material could be found between the piggyback lenses. CONCLUSIONS: Analyses of ILO cases where all the components of the opacifying material were in situ allowed us to confirm that the pathogenesis of this complication is similar to that of posterior capsule opacification; thus, careful removal of lens epithelial cells and cortical material is mandatory in piggyback implantation.