PubMed Health⌕ Search

Biomedical subjects

Nick Mamalis

Publications and source records attributed to Nick Mamalis.

At least 19 recordsLinked to original sources
PubMed2006

Outbreak of toxic anterior segment syndrome following cataract surgery associated with impurities in autoclave steam moisture.

BACKGROUND: Toxic anterior segment syndrome (TASS), a complication of cataract surgery, is a sterile inflammation of the anterior chamber of the eye. An outbreak of TASS was recognized at an outpatient surgical center and its affiliated hospital in December 2002. METHODS: Medical records of patients who underwent cataract surgery during the outbreak were reviewed, and surgical team members who participated in the operations were interviewed. Potential causes of TASS were identified and eliminated. Feedwater from autoclave steam generators and steam condensates were analyzed by use of spectroscopy and ion chromatography. RESULTS: During the outbreak, 8 (38%) of 21 cataract operations were complicated by TASS, compared with 2 (0.07%) of 2,713 operations performed from January 1996 through November 2002. Results of an initial investigation suggested that cataract surgical equipment may have been contaminated by suboptimal equipment reprocessing or as a result of personnel changes. The frequency of TASS decreased (1 of 44 cataract operations) after reassignment of personnel and revision of equipment reprocessing procedures. Further investigation identified the presence of impurities (eg, sulfates, copper, zinc, nickel, and silica) in autoclave steam moisture, which was attributed to improper maintenance of the autoclave steam generator in the outpatient surgical center. When impurities in autoclave steam moisture were eliminated, no cases of TASS were observed after more than 1,000 cataract operations. CONCLUSION: Suboptimal reprocessing of cataract surgical equipment may evolve over time in busy, multidisciplinary surgical centers. Clinically significant contamination of surgical equipment may result from inappropriate maintenance of steam sterilization systems. Standardization of protocols for reprocessing of cataract surgical equipment may prevent outbreaks of TASS and may be of assistance during outbreak investigations.

Anterior Eye Segment↗
PubMed2006

Role of silicon contamination on calcification of hydrophilic acrylic intraocular lenses.

PURPOSE: To verify the presence of the element silicon on hydrophilic acrylic intraocular lenses (IOLs) explanted because of calcification. DESIGN: Interventional case series with clinicopathological correlation. METHODS: Twenty explanted IOLs with surface deposits (MemoryLens), and 20 with deposits mostly within their optic substance (SC60B-OUV and Aqua-Sense; 10 each) were used. After gross, microscopic, and histochemical analyses to confirm the presence of deposits, the lenses underwent scanning electron microscopy (SEM) with energy dispersive x-ray spectroscopy (EDS) for elemental composition, on the external surface of MemoryLens IOLs, and on the surface and internal substance of SC60B-OUV and Aqua-Sense IOLs. The weight percentage of the element silicon was obtained at the level of deposits, and at adjacent deposit-free areas in all lenses. RESULTS: Scanning electron microscopy (SEM) coupled with EDS confirmed that the composition of the deposits was calcium/phosphate in all cases. The element silicon was found in all 40 lenses, on all areas analyzed. The silicon weight percentage was higher at the level of the deposits. The presence of aluminum on five MemoryLens IOLs, and in most of the SC60B-OUV and Aqua-Sense lenses might be related to scattering from the aluminum mounting stubs used for surface analyses. CONCLUSIONS: Silicone compounds have been implicated in the calcification of another hydrophilic acrylic design (Hydroview). They may also have a role in the calcification of other hydrophilic acrylic IOLs. Further investigation on the relationship between the presence of the element silicon and the silicone compounds found on calcified hydrophilic acrylic lenses is necessary.

Acrylic Resins↗
PubMed2006

Late opacification of a silicone intraocular lens caused by ophthalmic ointment.

A 55-year-old man had uneventful phacoemulsification with implantation of a 3-piece silicone intraocular lens (IOL). Postoperative medications included antibiotic-steroid drops and ointments. Eight months postoperatively, the patient started having recurrent episodes of anterior chamber inflammatory reaction. Suspicion that lens instability was causing the reactions led to a lens repositioning procedure 11 months after the initial surgical implantation and again at 13 months. Eighteen months postoperatively, the IOL had a "greasy" film. Despite antiinflammatory and antibiotic treatment, the clinical outcome did not improve. Twenty-seven months after implantation, the lens was exchanged with a hydrophilic acrylic IOL. The course after the exchange was uneventful. The explanted lens was examined by gross and microscopic evaluations, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and gas chromatography-mass spectrometry (GC-MS) using electronic ionization. Gross and microscopic evaluations confirmed the presence of a thin, oily film covering the IOL optic surface. Surface analyses at the level of the oily substance showed unspecific peaks of sodium, chloride, and potassium. The GC-MS analysis showed the presence of compounds characteristic of hydrocarbons, including docosane, tricosane, and tetracosane, which are commonly found in the vehicle of ophthalmic ointments. The GC-MS analysis of 1 ointment used postoperatively found matching peaks, suggesting deposition of those compounds on the IOL.

Device Removal↗
PubMed2006

Postoperative opacification of the peripheral optic region and haptics of a hydrophilic acrylic intraocular lens: case report and clinicopathologic correlation.

We report the first case of opacification of the BioComFold 92S (Morcher GmbH) intraocular lens. The opacification pattern is unique, presenting mainly in the periphery of the optic and the haptics of the lens, leaving the central portion of the optic clear. The clinical course of this opacification pattern is not observed typically with other hydrophilic acrylic lens designs and requires further study.

Aged↗
PubMed2006

Toxic anterior segment syndrome and possible association with ointment in the anterior chamber following cataract surgery.

PURPOSE: To report clinical and laboratory findings of 8 cases of toxic anterior segment syndrome (TASS) related to an oily substance in the anterior chamber of patients following cataract surgery with intraocular lens (IOL) implantation. SETTING: John Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: Eight patients had uneventful phacoemulsification by the same surgeon via clear corneal incisions with implantation of the same 3-piece silicone IOL design. Postoperative medications included antibiotic/steroid ointment and pilocarpine gel; each eye was firmly patched at the end of the procedure. On the first postoperative day, some patients presented with diffuse corneal edema, increased intraocular pressure, and an oily film-like material within the anterior chamber coating the corneal endothelium. The others presented with an oily bubble floating inside the anterior chamber, which was later seen coating the IOL. Additional surgical procedures required included penetrating keratoplasty, IOL explantation, and trabeculectomy. Two corneal buttons were analyzed histopathologically. Two explanted IOLs had gross and light microscopic analyses (as well as surface analyses of 1 of them), and 4 other explanted IOLs had gas chromatography-mass spectrometry. RESULTS: Pathological examination of the corneas showed variable thinning of the epithelium with edema. The stroma was diffusely thickened and the endothelial cell layer was absent. Evaluation of the explanted IOLs confirmed the presence of an oily substance coating large areas of their anterior and posterior optic surfaces. Gas chromatography-mass spectrometry of the lens extracts identified a mixed chain hydrocarbon compound that was also found in the gas chromatography-mass spectrometry analyses of the ointment used postoperatively. CONCLUSIONS: The results indicate that the ointment gained access to the eye, causing the postoperative complications described. These cases highlight the importance of appropriate wound construction and integrity, as well as the risks of tight eye patching following placement of ointment.

Aged↗
PubMed2006

Early opacification of silicone intraocular lenses: Laboratory analyses of 6 explants.

PURPOSE: To report laboratory analyses of 6 intraocular lenses (IOLs) explanted from patients who had visual disturbances caused by early postoperative opacification of the lens optic. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: Six patients with 3-piece silicone lenses presented with optic cloudiness as early as a few hours after implantation. The lenses were implanted in 4 locations in Brazil and in France. The lenses in Brazil were stored at the same location before implantation. Gross and microscopic analyses were performed (dry and hydrated states). One half of each specimen underwent gas chromatography/mass spectrometry (GC/MS) analysis and/or extraction by isopropyl alcohol or acetonitrile. One lens also underwent scanning electron microscopy (SEM) with energy dispersive x-ray spectroscopy (EDS). The IOLs were examined for the presence of contaminants or deposits that could cause fast optic opacification. RESULTS: The IOLs showed a white optic discoloration in the hydrated state but became transparent on complete dehydration. Suspect exogenous chemical compounds were identified in GC/MS analyses; general classes included terpenes and ketones, typically found in industrial cleaning agents and fumigants. Surface analysis (SEM and EDS) did not show any significant deposits on the external surfaces and sagittal cut in 1 of the specimens. CONCLUSIONS: Most IOLs are enclosed in semipermeable packages to allow sterilization by ethylene oxide gas. During cleaning or disinfection of storage rooms, aerosolized solutions may introduce chemicals through the package and onto the IOLs. This may cause surface changes in the IOL, promoting opacification by water ingress in the aqueous environment. Cleaning and disinfection procedures of IOL storage areas should be monitored carefully.

Aged↗
PubMed2006

Interlenticular opacification: dual-optic versus piggyback intraocular lenses.

PURPOSE: To evaluate and compare the incidence of capsular bag opacification, particularly interlenticular opacification (ILO), in rabbit eyes implanted with a dual-optic silicone intraocular lens (IOL) or piggyback lenses. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: Ten dual-optic study IOLs (Synchrony), 10 control pairs of piggyback silicone-plate lenses, and 10 control pairs of piggyback single-piece hydrophobic acrylic lenses were implanted in the capsular bag of 30 rabbit eyes following phacoemulsification. After a 6-week follow-up, the rabbits were killed and their eyes enucleated. Anterior capsule opacification and posterior capsule opacification were graded on a 0 to 4 scale from a posterior or Miyake-Apple view. Interlenticular opacification was noted in relation to the center of the interlenticular space (periphery, paracentral, and central area) and to the number of quadrants involved. The eyes were then evaluated histopathologically. RESULTS: Postoperative inflammatory reaction was similar in all groups. Interlenticular opacification formation was statistically different among the 3 groups of lenses (ILO extension, P = .0013, and ILO extension x ILO quadrants, P = .0023; Kruskal-Wallis test). Pairwise post comparisons of ILO formation showed that the differences between the study IOL group and the silicone-plate lens group were not significant. Interlenticular opacification post comparisons between the hydrophobic acrylic lenses and the study lens or the silicone-plate lenses were significant (P = .002 and P = .001, respectively). Histopathologic examination showed extension of the proliferating cortical material from the peripheral Soemmering's ring into the interlenticular space, causing ILO, especially with the pairs of hydrophobic acrylic lenses. CONCLUSIONS: In this rabbit model, ILO was significantly associated with pairs of hydrophobic acrylic lenses implanted in the bag. This study appears to confirm clinical observations that implantation of 2 silicone-plate lenses in the bag is not associated with ILO. There was also a relative lack of ILO with the dual-optic silicone lens.

Animals↗
PubMed2006

Hydrophilic acrylic intraocular lens as a drug-delivery system: Pilot study.

PURPOSE: To evaluate the ability of a hydrophilic acrylic intraocular lens (IOL) to serve as a drug-delivery system for commercially available gatifloxacin and moxifloxacin. SETTING: David J. Apple, MD, Laboratories for Ophthalmic Devices Research, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: Hydrophilic acrylic IOLs (C-flex, Rayner Ltd.), presoaked for 24 hours in commercially available solutions of gatifloxacin (Zymar) or moxifloxacin (Vigamox), were implanted in the capsular bag of 6 rabbits for a total of 12 eyes (6 in each group). Aqueous humor samples were taken 2, 4, and 6 hours after implantation. One rabbit served as a control and had nonpresoaked C-flex IOLs implanted. At the end of the operation, 1 drop of Vigamox was applied to the right eye and 1 drop of Zymar was applied to the left eye of the control rabbit. RESULTS: High concentrations of both antibiotics were found in all the samples of the eyes implanted with the presoaked IOLs. The concentrations of the antibiotics decreased over time, but even the 6-hour sample concentrations were markedly higher than the concentrations found in the control rabbit after 4 hours. CONCLUSION: The results suggest that the Rayner C-flex IOL can be effective as a drug-delivery system for fourth-generation fluoroquinolones.

Acrylic Resins↗
PubMed2006

Toxic anterior segment syndrome.

Toxic anterior segment syndrome (TASS) is a sterile postoperative inflammatory reaction caused by a noninfectious substance that enters the anterior segment, resulting in toxic damage to intraocular tissues. The process typically starts 12 to 48 hours after cataract/anterior segment surgery, is limited to the anterior segment of the eye, is always Gram stain and culture negative, and usually improves with steroid treatment. The primary differential diagnosis is infectious endophthalmitis. Review of the literature indicates that possible causes of TASS include intraocular solutions with inappropriate chemical composition, concentration, pH, or osmolality; preservatives; denatured ophthalmic viscosurgical devices; enzymatic detergents; bacterial endotoxin; oxidized metal deposits and residues; and factors related to intraocular lenses such as residues from polishing or sterilizing compounds. An outbreak of TASS is an environmental and toxic control issue that requires complete analysis of all medications and fluids used during surgery, as well as complete review of operating room and sterilization protocols.

Anterior Eye Segment↗
PubMed2006

Two opacification patterns of the same hydrophilic acrylic polymer: case reports and clinicopathological correlation.

We report 2 intraocular lenses (IOLs) manufactured from the same hydrophilic acrylic polymer by Ioltech that developed optic opacification. In both cases, the postoperative course after implantation of the IOLs was complicated by significant inflammatory reaction with fibrin formation in the anterior chamber. Pathologic analyses of the explanted IOLs were consistent with dystrophic calcification leading to optic opacification, but the pattern was different between the 2 IOL designs. Patient-related factors might have been responsible for this complication.

Acrylic Resins↗
PubMed2006

New photochromic foldable intraocular lens: preliminary study of feasibility and biocompatibility.

PURPOSE: To evaluate a new hydrophobic acrylic intraocular lens (IOL) with photochromic properties in vitro and in vivo in a rabbit model. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: The photochromic optic change of 5 study IOLs was evaluated in vitro on ultraviolet (UV) light exposure. The tests were done in the dry state and during immersion of the lenses in a balanced salt solution. Six additional IOLs were implanted in the right eye of New Zealand rabbits. The left eyes were implanted with SA60AT or SN60AT IOLs (Alcon Laboratories, 3 each). After a clinical follow-up of 6 months, the rabbits were killed and their eyes enucleated. Three study IOLs and 2 control SN60AT IOLs were evaluated in vitro on UV exposure after explantation. The other IOLs and the rabbit eyes had histopathologic examination. RESULTS: On in vitro UV light exposure, the optic of the study IOLs changed from colorless to yellow, turning again colorless on discontinuation of UV light projection. The same photochromic change was also observed on UV light exposure throughout the clinical follow-up of 6 rabbits, as well as after explantation of the IOLs. Postoperative clinical inflammatory reactions and cellular reactions on the surface of the explanted IOLs were similar in the study and control groups. No sign of untoward toxicity was observed in the histopathological sections of the rabbit eyes in all groups. CONCLUSIONS: The new photochromic IOL turned yellow only on exposure to UV light; otherwise it remained clear. This lens was also found to be biocompatible.

Acrylic Resins↗
PubMed2006

Toxic anterior segment syndrome after Verisyse iris-supported phakic intraocular lens implantation.

We report a case of toxic anterior segment syndrome (TASS) after implantation of a Verisyse (AMO) iris-supported phakic intraocular lens (IOL). The patient presented the day after surgery with significant decreased visual acuity and severe, persistent, limbus-to-limbus corneal edema. After treatment with topical steroids, oral steroids, nonsteroidal antiinflammatory agents, and hypertonic solution, the edema resolved over the course of 2 months and best corrected visual acuity improved to 20/20. Toxic anterior segment syndrome has been reported after implantation of IOLs previously, but this new case of TASS should alert surgeons to the possibility of the syndrome after phakic IOL placement.

Adult↗
PubMed2006

A light adjustable lens with injectable optics.

The light adjustable lens (LAL) is an innovative intraocular lens optic composed of partially polymerized macromers with an appropriately bonded photosensitizer. The injectable technology and multifocality associated with the LAL can produce precise refractive correction and, it is hoped, the type of accommodative range that is taken for granted during youth. Combining these technologies with a lens material that behaves like the crystalline lens of 25-year-old could precisely return near and distance vision to older adults.

Accommodation, Ocular↗
PubMed2006

New endoscopic technique to analyze various modern specialized intraocular lenses in research eyes and human eyes obtained postmortem.

PURPOSE: To describe a new modification of the Miyake-Apple posterior video photographic technique and its 2 variations. We have developed a new endoscopic technique that is especially amenable for observation of modern specialized intraocular lenses (IOLs). DESIGN: Laboratory study. PARTICIPANT: Three cadaver eyes obtained postmortem. METHODS: Human eyes obtained postmortem were prepared according to our modified preparation technique used for analyses of whole globes. An intraocular endoscope was utilized to demonstrate all aspects of the interior of an experimentally implanted IOL, with specialized reference to anterior segment structures, obtaining posterior, oblique, and side view images. MAIN OUTCOME MEASURES: Different interior dynamic views of the anterior segment structures before and after implantation of an IOL. RESULTS: High-magnification images of different intraocular structures both before and after device insertion as well as the device itself were obtained. Oblique and side view images from different locations were also available and informative. These images helped to create a 3-dimensional view of these objects and their relations to the surrounding structures. CONCLUSION: The combination of the intraocular endoscope with the closed-system technique is a useful addition to our 3 previously described techniques: (1) the original Miyake-Apple posterior video/photograph technique and the (2) closed system and (3) side/oblique view (keyhole technique) modifications.

Anterior Eye Segment↗