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Dive into the research topics where Michael E. Snyder is active.

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Featured researches published by Michael E. Snyder.


Ophthalmology | 2000

Indocyanine green-assisted peeling of the retinal internal limiting membrane.

Scott E. Burk; Andrea P. Da Mata; Michael E. Snyder; Robert H. Rosa; Robert E. Foster

OBJECTIVE To determine whether indocyanine green (ICG) stains and facilitates peeling of the retinal internal limiting membrane (ILM). To investigate the different staining properties of the posterior cortical hyaloid, retinal ILM, and the retina after ILM removal. DESIGN Autopsy eye study. MATERIALS Eleven human cadaveric eyes. METHODS Open sky vitrectomy including removal of the posterior cortical vitreous was performed. A 0.5% ICG solution was then injected into the posterior vitreous cavity over the macula. The dye was allowed to settle on the macula for 5 minutes and was then removed by mechanical aspiration. Peeling of the ILM was initiated with a bent needle and completed with intraocular forceps. Specimens were submitted for light and electron microscopy. MAIN OUTCOME MEASURES Staining properties and ease of peeling of retinal ILM were evaluated. Retinal ILM removal was confirmed by histopathologic and electron microscopic examination. RESULTS ICG contact with the retinal surface resulted in bright green staining of the ILM. This stain greatly facilitated ILM peeling by improving direct visualization of the membrane. The underlying retina did not stain, thus providing a clear distinction between the stained ILM and the unstained retina. Continuous circular peeling of the ILM was easily completed with this technique. Light microscopic and ultrastructural studies confirmed removal of the ILM. CONCLUSIONS ICG solution distinctly stains the nearly invisible retinal ILM in human cadaveric eyes. ICG staining greatly facilitates ILM peeling by providing a stark contrast between the stained ILM and the unstained retina.


Ophthalmology | 2000

Indocyanine green–assisted peeling of the retinal internal limiting membrane1

Scott E. Burk; Andrea P. Da Mata; Michael E. Snyder; Robert H. Rosa; Robert E. Foster

OBJECTIVE To determine whether indocyanine green (ICG) stains and facilitates peeling of the retinal internal limiting membrane (ILM). To investigate the different staining properties of the posterior cortical hyaloid, retinal ILM, and the retina after ILM removal. DESIGN Autopsy eye study. MATERIALS Eleven human cadaveric eyes. METHODS Open sky vitrectomy including removal of the posterior cortical vitreous was performed. A 0.5% ICG solution was then injected into the posterior vitreous cavity over the macula. The dye was allowed to settle on the macula for 5 minutes and was then removed by mechanical aspiration. Peeling of the ILM was initiated with a bent needle and completed with intraocular forceps. Specimens were submitted for light and electron microscopy. MAIN OUTCOME MEASURES Staining properties and ease of peeling of retinal ILM were evaluated. Retinal ILM removal was confirmed by histopathologic and electron microscopic examination. RESULTS ICG contact with the retinal surface resulted in bright green staining of the ILM. This stain greatly facilitated ILM peeling by improving direct visualization of the membrane. The underlying retina did not stain, thus providing a clear distinction between the stained ILM and the unstained retina. Continuous circular peeling of the ILM was easily completed with this technique. Light microscopic and ultrastructural studies confirmed removal of the ILM. CONCLUSIONS ICG solution distinctly stains the nearly invisible retinal ILM in human cadaveric eyes. ICG staining greatly facilitates ILM peeling by providing a stark contrast between the stained ILM and the unstained retina.


Journal of Cataract and Refractive Surgery | 2003

Visualizing vitreous using Kenalog suspension.

Scott E. Burk; Andrea P. Da Mata; Michael E. Snyder; Susan Schneider; Robert H. Osher; Robert J. Cionni

&NA; 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 &mgr;m 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.


Journal of Cataract and Refractive Surgery | 2001

Prosthetic iris implantation for congenital, traumatic, or functional iris deficiencies

Scott E. Burk; Andrea P. Da Mata; Michael E. Snyder; Robert J. Cionni; John S. Cohen; Robert H. Osher

Purpose: To determine the efficacy and safety of surgical implantation of prosthetic iris devices in patients with anatomic or functional iris deficiencies. Setting: Cincinnati Eye Institute, Cincinnati, Ohio, USA. Methods: Twenty‐five patients were enrolled in an interventional prospective noncomparative case series. Twenty‐eight eyes had prosthetic iris diaphragm implantation for traumatic iris defects, congenital aniridia or iris coloboma, herpetic iris atrophy, surgical iris loss, or ocular albinism. Prosthetic iris implantation was performed with phacoemulsification and intraocular lens (IOL) implantation in 20 eyes, secondary IOL implantation in 6 eyes, and IOL exchange in 1 eye. A single pseudophakic eye with disabling glare secondary to traumatic aniridia had secondary prosthetic iris implantation alone. The surgical ease of insertion, intraoperative and postoperative complications, postoperative anatomic results, visual acuity, and subjective glare reduction were evaluated. Results: Patients were followed postoperatively for a mean of 10.2 months (range 1.4 to 25.7 months). All eyes achieved the desired anatomic result. Visual acuity was improved in 22 of 28 eyes (79%), unchanged in 5 eyes, and worsened by a single line in 1 eye. Patients were surveyed postoperatively to determine the change in glare disability. The severity of glare disability was subjectively improved in 23 of 24 patients (96%) who responded to the survey. Intraoperative complications included 3 fractured implants as well as an incomplete or torn capsulorhexis in 3 eyes. Postoperative complications included transient hypotony in 2 eyes, mild persistent inflammation in 1 eye, and macular edema followed by a retinal detachment in 1 eye with recent severe trauma. Conclusions: Implantation of prosthetic iris devices improved postoperative outcomes by reducing glare disability and, in selected cases, by correcting aphakia. Although operating on traumatized, congenitally aniridic, or uveitic eyes presents special challenges, implantation of prosthetic iris devices appears to be a safe and effective method for reducing the ubiquitous glare in patients with iris deficiency.


Journal of Cataract and Refractive Surgery | 2003

Modified capsular tension ring for patients with congenital loss of zonular support.

Robert J. Cionni; Robert H. Osher; Daniela M.V Marques; Frederico F. Marques; Michael E. Snyder; Scott Shapiro

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 Marfans 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.


Journal of Cataract and Refractive Surgery | 2009

Visual outcome comparison of unilateral versus bilateral implantation of apodized diffractive multifocal intraocular lenses after cataract extraction: Prospective 6-month study

Robert J. Cionni; Robert H. Osher; Michael E. Snyder; Michael L. Nordlund

PURPOSE: To evaluate the visual outcomes and patient satisfaction after unilateral implantation or stepwise bilateral implantation of an apodized diffractive multifocal intraocular lens (IOL). SETTING: Private practice, Cincinnati, Ohio, USA. METHODS: Patients requiring cataract surgery in 1 eye were recruited. AcrySof ReSTOR IOLs were implanted in 1 eye of patients with phakic contralateral eyes, patients with contralateral monofocal IOLs, and patients with a contralateral multifocal IOL of the same model. Six months postoperatively, patients were assessed for visual acuity (31.0 cm, 50.0 cm, 4.0 m), contrast sensitivity, and stereopsis. Patients were surveyed for visual disturbances and lifestyle visual quality. RESULTS: Of unilateral multifocal IOL patients, 75% were satisfied with their vision (score 7.3 out of 10) and a majority (56% multifocal–phakic, 65% multifocal–monofocal) achieved spectacle independence. These values were slightly lower than values for bilateral multifocal patients (92% satisfied, 77% spectacle independent), but not at a statistically significant level. Mean overall patient satisfaction was statistically significantly different: 8.9 for bilateral patients versus 7.3 for unilateral patients. Objectively, significant differences favored bilateral implantation over unilateral implantation for stereopsis, uncorrected near visual acuity, and best corrected near and intermediate visual acuities. Contrast sensitivity was similar between groups in most cases. The incidence of halos was lower in unilateral patients (57%) than in bilateral patients (77%), although the difference did not reach statistical significance. CONCLUSION: Although unilateral implantation of a multifocal IOL provided patients with high levels of spectacle freedom and good visual acuity without compromising contrast sensitivity, overall clinical results favored bilateral implantation.


Journal of Cataract and Refractive Surgery | 2013

Management of the subluxated crystalline lens.

Richard S. Hoffman; Michael E. Snyder; Uday Devgan; Quentin B. Allen; Ronald Yeoh; Rosa Braga-Mele

The surgical management of ectopia lentis presents the ophthalmic surgeon with numerous challenges and options. From the clinical evaluation to the surgical approach, ectopia lentis patients require additional methodologies, techniques, and devices to ensure the best possible outcome. The continued refinement of surgical techniques and adjunctive prosthetic devices has led to incremental improvements in the ability to achieve successful in-the-bag placement and centration of intraocular lenses while reducing complications. A thorough understanding of the challenges inherent in ectopia lentis cases and the management of intraoperative complications will ensure that surgeons approaching the correction of these eyes will achieve the best possible surgical results.


Journal of Cataract and Refractive Surgery | 2007

Outcomes of prosthetic iris implantation in patients with albinism

Ekaterini C. Karatza; Scott E. Burk; Michael E. Snyder; Robert H. Osher

PURPOSE: To assess the safety and efficacy of implantation of prosthetic iris devices in patients with albinism. SETTING: Private practice, Cincinnati, Ohio, USA. METHODS: This retrospective noncomparative case series comprised 13 eyes of 8 patients with diminished pigment epithelium of the iris secondary to albinism. All eyes had anterior segment surgery with intraocular lens (IOL) and prosthetic iris device implantation. Eleven eyes received an endocapsular‐type iris reconstruction implant (Morcher aniridia interdigitating rings), and 2 eyes (1 patient) received a combined iris–IOL device (Ophtec model 311). The visual acuity, subjective glare reduction, postoperative anatomical outcomes, and intraoperative or postoperative complications were reviewed. RESULTS: All eyes achieved the desired anatomic result. The best corrected visual acuity improved in 8 of 13 eyes, remained stable in 3 eyes, and decreased in 2 eyes. Glare and photophobia improved subjectively in 6 of 8 patients, remained unchanged in 1 patient, and increased in 1 patient after implantation of an artificial iris diaphragm. There were no intraoperative or postoperative complications. CONCLUSIONS: Implantation of prosthetic iris devices appears to be useful in the management of patients with iris deficiency secondary to albinism. The procedure was safe and particularly effective in reducing glare and photophobia in most patients.


Canadian Journal of Ophthalmology-journal Canadien D Ophtalmologie | 2014

Prosthetic iris devices

Sathish Srinivasan; Darren S.J. Ting; Michael E. Snyder; Somdutt Prasad; Hans-Reinhard Koch

Congenital iris defects may usually present either as subtotal aniridia or colobomatous iris defects. Acquired iris defects are secondary to penetrating iris injury, iatrogenic after surgical excision of iris tumours, collateral trauma after anterior segment surgery, or can be postinflammatory in nature. These iris defects can cause severe visual disability in the form of glare, loss of contrast sensitivity, and loss of best corrected visual acuity. The structural loss of iris can be reconstructed with iris suturing, use of prosthetic iris implants, or by a combination of these, depending on the relative amount of residual iris stromal tissue and health of the underlying pigment epithelium. Since the first implant of a black iris diaphragm posterior chamber intraocular lens in 1994, advances in material and design technology over the last decade have led to advances in the prosthetic material, surgical technique, and instrumentation in the field of prosthetic iris implants. In this article, we review the classification of iris defects, types of iris prosthetic devices, implantation techniques, and complications.


Journal of Cataract and Refractive Surgery | 2011

Randomized comparison of postoperative use of hydrogel ocular bandage and collagen corneal shield for wound protection and patient tolerability after cataract surgery

Steven J. Dell; John Hovanesian; Michael B. Raizman; Alan S. Crandall; John F. Doane; Michael E. Snyder; Samuel Masket; Stephen S. Lane; Nicole R. Fram

PURPOSE: To compare the safety and efficacy of a hydrogel bandage and a collagen corneal shield in providing wound protection and relief of pain/discomfort in the acute period after uneventful unilateral clear corneal phacoemulsification cataract surgery with foldable intraocular lens (IOL) implantation. SETTING: Seventeen investigational sites in the United States. DESIGN: Prospective randomized single‐masked parallel study. METHODS: The study comprised patients scheduled to have unilateral clear corneal cataract surgery with posterior chamber intraocular lens implantation. The patients were examined preoperatively and frequently for 30 days postoperatively. The design was a noninferiority study of the 2 primary endpoints, device performance and maximum reported postoperative pain. RESULTS: The device performance success was 78.6% (228/290) for the hydrogel bandage and 26.5% (26/98) for the corneal shield (P<.0001 for noninferiority). Analyses indicated that the hydrogel bandage was superior to the corneal shield in device performance (P<.001; difference = 52.1%; 95% confidence interval, 41.6%‐61.4%). The maximum postoperative pain/discomfort score of the hydrogel bandage (mean 1.3 ± 1.8 [SD]; scale 0 to 10) was noninferior to that of the corneal shield (1.1 ± 1.6) in the first 4 hours after surgery (P<.001). Adverse events in the cataract surgeries were reported in 22.2% (70/316) and 36.5% (38/104) of hydrogel bandage patients and corneal shield patients, respectively (P = .0045). CONCLUSION: The hydrogel bandage was safe and effective for ocular surface protection and relief of pain/discomfort when applied topically to clear corneal incisions used in cataract or IOL implantation surgery. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes.

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Robert H. Osher

University of Cincinnati Academic Health Center

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Robert J. Cionni

University of Cincinnati Academic Health Center

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Andrea P. Da Mata

Universidade Federal de Minas Gerais

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Samuel Masket

University of California

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