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At least 1,081 records · Page 60Linked to original sources
PubMed2005

Posterior capsule opacification in rabbit eyes implanted with 1-piece and 3-piece hydrophobic acrylic intraocular lenses.

PURPOSE: To evaluate the outcome of posterior capsule opacification (PCO) after implantation in rabbit eyes of currently available 3-piece and 1-piece hydrophobic acrylic intraocular lenses (IOLs) with square optic edges. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: The 3-piece designs evaluated were the AR40e (Advanced Medical Optics Inc.) and the MA60AC (Alcon, Inc.); the 1-piece designs were the SA60AT and the SA30AT (Alcon, Inc.). Nine lenses of each type were implanted in a randomized manner by the same surgeon in 18 Dutch Belted pigmented rabbits. After a follow-up of 3 weeks, the rabbits were killed and analyses of the enucleated eyes were performed from the posterior or Miyake-Apple view. The intensity of central PCO, peripheral PCO, and Soemmering's ring formation was scored from 0 to 4. The area of Soemmering's ring formation was also scored from 0 to 4 based on the number of quadrants involved. Other parameters analyzed were capsulorhexis coverage of the IOL anterior surface, IOL centration, fixation, and presence of striae. Results from the posterior view were complemented by histopathologic evaluation of the eyes. RESULTS: No statistically significant difference was found between the 4 groups of IOLs in the parameters analyzed from the posterior view. When cell ingrowth occurred with the 1-piece designs, causing peripheral and central PCO formation, it was more likely to start at the optic-haptic junctions, as observed during the clinical follow-up with slitlamp examination and confirmed by gross and histopathologic analyses of the enucleated eyes. CONCLUSIONS: The square, truncated optic edge is the most important IOL design feature for PCO prevention. The optic-haptic junctions of the 1-piece designs appear to be sites where the barrier effect of the truncated optic edge is less effective.

Acrylic Resins↗
PubMed2005

Laser in situ keratomileusis for primary hyperopia.

PURPOSE: To evaluate the efficacy, predictability, stability, and safety of hyperopic laser in situ keratomileusis (H-LASIK) over a 24-month period and analyze topographic changes after H-LASIK to assess topographic pseudokeratectasia (TPKE) following H-LASIK. SETTING: Eye Institute of Utah, Salt Lake City, Utah, USA. METHODS: This prospective study included 139 eyes of 77 patients having H-LASIK for primary hyperopia. The mean follow-up was 15.6 months +/- 7.6 (SD) (range 6 to 48 months). One hundred twenty-two eyes (88%) were followed at 1 year and 36 eyes (26%) at 24 months. Topographic pseudokeratectasia was defined as 1 or more positive keratoconus screening findings in an eye with topographic central or inferior steepening detected by the Topography Modeling System but without corneal thinning or progressive change. RESULTS: The mean spherical equivalent manifest refraction was +2.39 +/- 0.99 diopter (D) preoperatively and -0.05 +/- 0.61 D at the last visit. Ninety-one percent of eyes were within +/-1.00 D of emmetropia and 71% of the eyes were within +/-0.50 D. Uncorrected visual acuity of 20/20 or better was present in 42%, 20/25 in 63%, and 20/40 or better in 93% of eyes. Loss of 2 lines of BSCVA occurred in 2 eyes (1.4%). In 1 eye, ischemic optic neuropathy occurred, and in another, choroidal neovascularization developed postoperatively. Topographic pseudokeratectasia was detected in 28% to 56% of eyes postoperatively. No significant difference between postoperative visual and refractive outcome, regression, or irregularity was found between the eyes with or without TPKE. CONCLUSION: Hyperopic LASIK appears to be an effective, predictable, and safe procedure to correct low to moderate primary hyperopia. Topographic pseudokeratectasia, which was observed after H-LASIK with a keratoconus-like topographic pattern in otherwise normal eyes, may represent a relatively static condition.

Adult↗
PubMed2005

Evaluation of the cataractogenic effect of viscoanesthetic solutions on the rabbit crystalline lens.

PURPOSE: To evaluate the toxicity and cataractogenic effect of solutions combining sodium (Na) hyaluronate 1.0% and 1.5% with lidocaine 1.0% on the rabbit crystalline lens. The amount of pupil dilation provided by the addition of lidocaine to the Na hyaluronate solutions was also assessed. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: Five solutions were injected into the anterior chamber of 18 pigmented rabbits in a randomized manner by the same surgeon, the intraocular component of VisThesia (Na hyaluronate 1.5%/lidocaine 1.0%), the intraocular component of VisThesia Light (Na hyaluronate 1.0%/lidocaine 1.0%), Ophthalin Plus (Na hyaluronate 1.5%), and a balanced salt solution; and both eyes of 2 other rabbits were injected with nonpreserved aqueous lidocaine 1.0%. The pupil diameter of each eye was measured before injection, immediately after, and 1 and 5 minutes after injection. After a follow-up of 3 months with slitlamp examinations, the rabbits were killed, and their eyes were enucleated. The crystalline lenses were evaluated from a posterior or Miyake-Apple view, and the eyes were fixated in 10% formalin for histopathologic analyses. RESULTS: Pupil diameter was significantly larger 1 and 5 minutes after injection in the VisThesia (P = .01 and P = .007) and VisThesia Light (P = .008 and P = .007) groups, whereas the differences were not significant in the Ophthalin Plus (P = .317 and P = .102) and balanced salt solution groups (P = .317 and P = .180). Fast and large pupillary dilation was observed in the aqueous lidocaine group, starting during the injection. No differences in the transparency of the natural lens and the red fundus reflex were noted during slitlamp examinations. Postmortem analyses from a posterior view also showed no differences in the transparency of the crystalline lens. The histopathologic appearance of the lens capsule, anterior and equatorial lens epithelial cells, and epithelial lens bow was comparable in the eyes, without signs of cell vacuolization or disruption. CONCLUSIONS: Intracameral injection of the solutions used in this study caused no localized opacity or overall change in the transparency of the crystalline lenses as observed during clinical and postmortem examinations as well as histopathologic analyses of the enucleated rabbit eyes. Viscoanesthesia may have application in phakic intraocular lens implantation.

Anesthetics, Local↗
PubMed2005

Experimental evaluation of the Corneal Concept 360 intraocular lens with the Miyake-Apple view.

PURPOSE: To evaluate a new single-piece, hydrophilic acrylic intraocular lens (IOL) designed to keep the anterior capsule away from the IOL optic, create the effect of a capsular tension ring, and prevent posterior capsule opacification (PCO). SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. MATERIALS AND METHODS: Four Concept 360 IOLs (Corneal Laboratoire) were implanted in 4 human cadaver eyes of various sizes (Miyake-Apple technique). Lens centration, ovalization of the capsular bag and capsulorhexis opening, distance between the anterior optic surface and the anterior capsule and between the posterior optic surface and the posterior capsule, as well as presence of capsular striae were evaluated. The capsular bag was stained with trypan blue, and the ophthalmic viscosurgical device (OVD) was stained with fluorescein to enhance visualization. RESULTS: In each eye, the lens conformed to the capsular bag with precise centration. No ovalization or distortion of the capsular bag or the capsulorhexis and no posterior capsule striae were observed. Measurements of the capsulorhexis diameter before and after IOL implantation were the same. The anterior capsule remained at distance from the anterior optic surface for 360 degrees, and tight contact between the posterior optic edge and the posterior capsule was observed. CONCLUSIONS: Use of the Miyake-Apple technique is useful in the evaluation of new IOL designs in experimental studies. Design features of the Concept 360 IOL are likely to decrease the outcome of postoperative capsular bag opacification. Long-term clinical studies are necessary to confirm these findings.

Acrylic Resins↗
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

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

Thermal inertia associated with ultrapulse technology in phacoemulsification.

PURPOSE: To determine whether very short pulses of ultrasound (5 to 6 milliseconds) have less heat propagation in biological tissue (thermal inertia) than traditional pulses (50 milliseconds). SETTING: Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences Center, Salt Lake City, Utah. METHODS: Thermal testing was done in balanced salt solution (BSS) and in eye-bank eyes. In the same fresh human eye-bank eye, net temperature increase after 20 seconds of ultrasound (50 milliseconds on and 50 milliseconds off) was compared with the increase after 6 milliseconds on and 12 milliseconds off with the same phacoemulsification unit. The same experiment and setting was run in BSS and the eye-bank ratios compared with the BSS ratios. Twenty runs were done at each power setting in BSS and 22 in the eye-bank eye. RESULTS: There was 10.9% less heat generated with 6-millisecond pulses of ultrasound in limbal tissue than in BSS compared with 50-millisecond pulses of ultrasound (P = .0002). CONCLUSION: Very short pulses of ultrasound (5 to 6 milliseconds) propagated less thermal energy in limbal tissue than in BSS compared with 50-millisecond ultrasound pulses.

Acetates↗
PubMed2006

Hydrophilic acrylic intraocular lens as a drug-delivery system for fourth-generation fluoroquinolones.

PURPOSE: To evaluate the ability and safety of a hydrophilic acrylic intraocular lens (IOL) as a drug-delivery system for commercially available gatifloxacin and moxifloxacin. SETTING: David J. Apple, MD, Laboratories for Ophthalmic Research, John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, USA. METHODS: Thirty rabbits were divided into 2 similar groups. In Group A (15 rabbits, 30 eyes), hydrophilic acrylic IOLs (C-flex, Rayner Intraocular Lenses, Ltd.) presoaked for 24 hours in commercially available solutions of gatifloxacin 3 mg/mL or moxifloxacin 5 mg/mL were implanted after evacuation of the crystalline lens. Group B (15 rabbits, 30 eyes) had topical preoperative and postoperative cataract prophylaxis with gatifloxacin 3 mg/mL or moxifloxacin 5 mg/mL; IOLs that were not presoaked were also implanted after evacuation of the crystalline lenses. In both groups, aqueous humor samples were taken 4, 8, or 12 hours after IOL implantation (5 eyes at each time point) to determine the antibiotic concentrations. Clinical examinations were performed 24 hours postoperatively. RESULTS: The antibiotic concentrations in Group A (presoaked IOLs) were statistically significantly higher than those in Group B (topical) for both antibiotics in all postoperative samples except moxifloxacin at 12 hours. In both groups, there was no statistically significant difference between the concentrations of the 2 antibiotics. No eye showed signs of clinical toxicity. CONCLUSION: Results show the C-flex IOL is a safe and effective drug-delivery system for fourth-generation fluoroquinolones.

Acrylic Resins↗
PubMed2006

Long-term capsular bag survival without functional lens epithelial cells.

PURPOSE: To evaluate the survival of the capsular bag without the support of functional lens epithelial cells (LECs). SETTING: David J. Apple, MD, Laboratories for Ophthalmic Devices Research, John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, USA. METHODS: One hundred slides of cadaver pseudophakic eyes (from 1991 to 2000) stained with hematoxylin and eosin were analyzed to determine the presence of Soemmering's ring, integrity of the capsular bag, fixation configuration of the haptics, and presence and functionality of the LECs. RESULTS: A Soemmering's ring was present in 69% of cases. The capsular bags were intact in 100% of cases. In-the-bag fixation was seen in 44% of cases. In 89% of cases, either no cells or nonfunctional LECs were found. CONCLUSION: Results suggest the capsular bag can survive anatomically without the support of functioning LECs.

Epithelial Cells↗
PubMed2006

Postoperative surface deposits on intraocular lenses in children.

PURPOSE: To report the clinicopathologic features of 4 intraocular lenses (IOLs) composed of 3 different hydrophilic biomaterials explanted from children who had postoperative opacification of the IOL optic. SETTING: David J Apple, MD, Laboratories for Ophthalmic Devices Research, John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, USA. METHODS: The IOLs were explanted 20, 11, 22, and 25 months postoperatively from children aged 10, 3, 36, and 20 months old, respectively, at IOL implantation. Clinical data were obtained to correlate the findings with possible associated risk factors. The explanted IOLs were examined by gross and light microscopy. They were further analyzed with a stain for calcium, alizarin red 1%. Scanning electron microscopy and energy dispersive X-ray spectroscopy (EDS) were also performed. RESULTS: The primary reason for cataract surgery in Case 1 and Case 2 was persistent hyperplastic primary vitreous (PHPV); 1 patient received a B-Lens IOL (Hanita) and the other a Centerflex IOL (Rayner). The primary reason in Case 3 was familial bilateral congenital cataract and in Case 4, rubella cataract; both patients received a Hydroview IOL (Bausch & Lomb). All 4 IOLs had surface deposits on the optic, but the morphology of the deposits on the B-Lens and Centerflex IOLs was different than that in previously reported cases. The deposits in all four cases stained positive with alizarin red and consisted of calcium and phosphorus when imaged with EDS. CONCLUSIONS: Calcified deposits on 2 Hydroview IOLs explanted from children were similar to those seen in adults with the same IOL. The deposits on the B-Lens and Centerflex IOLs were probably secondary to a breakdown of the blood-aqueous barrier caused by preexisting PHPV.

Anthraquinones↗
PubMed1994

Ovulation induction with gonadotropins and intrauterine insemination compared with in vitro fertilization and no therapy: a prospective, nonrandomized, cohort study and meta-analysis.

OBJECTIVES: To determine whether one to four cycles of ovulation induction with hMG and IUI or one cycle of IVF results in the highest pregnancy rate and is least expensive and whether published pregnancy rates for one to four cycles of hMG and IUI results in a higher pregnancy rate than rates for one cycle of IVF, zygote intrafallopian transfer (ZIFT), or GIFT. DESIGN: Prospective, nonrandomized, cohort study. Patients were excluded who were infertile for < 18 months, had a significant male factor, had greater than mild endometriosis, or had bilateral nonpatency of the fallopian tubes. Cohort groups included 47 hMG and IUI patients (99 cycles), 19 IVF patients (19 cycles), and 21 patients (210 cycles) receiving no treatment. A meta-analysis on accumulated hMG and IUI data using similar entry criteria was also performed. Theoretical calculations were performed and stable fecundity assumed to compare with national data on IVF, ZIFT, and GIFT. SETTING: Fertility Center, Division of Reproductive Endocrinology, University of Utah, Salt Lake City, Utah. RESULTS: A course of therapy with one to four cycles of hMG and IUI was just as effective as one cycle of IVF in achieving pregnancy. No significant difference in pregnancy rates was found between one IVF cycle and one to four cycles of hMG and IUI in our population. In vitro fertilization was more expensive than four cycles of hMG and IUI. Both IVF and hMG and IUI were more effective than no therapy. Published data also suggest that four cycles of hMG and IUI theoretically result in higher pregnancy rates than one cycle of IVF, ZIFT, or GIFT. CONCLUSION: Cost-benefit analysis comparing hMG and IUI, IVF, and no therapy in infertility patients may favor a course of four cycles of hMG and IUI as the first line of therapy. Using meta-analysis and theoretical assumptions, the pregnancy rate for one cycle of hMG and IUI is inferior to IVF, GIFT, or ZIFT; two cycles are comparable to IVF or ZIFT and inferior to GIFT; three cycles are superior to IVF or ZIFT and comparable to GIFT; and four cycles are theoretically superior to all techniques.

Adult↗
PubMed2001

The development of a stochastic physiologically-based pharmacokinetic model for lead.

This presentation describes the development of a prototype Monte Carlo module for the physiologically-based pharmacokinetic (PBPK) model for lead, created by Dr Ellen O'Flaherty. The module uses distributions for the following: exposure parameters (soil and dust concentrations, daily soil and ingestion rate, water lead concentration, water ingestion rate, air lead concentration, inhalation rate and dietary lead intake); absoption parameters; and key pharmacokinetic parameters (red blood binding capacity and half saturation concentration). Distributions can be specified as time-invariant or can change with age. Monte Carlo model predicted blood levels were calibrated to empirically measured blood lead levels for children living in Midvale, Utah (a milling/smelting community). The calibrated model was then evaluated using blood lead data from Palmerton, Pennsylvania (a town with a former smelter) and Sandy, Utah, (a town with a former smelter and slag piles). Our initial evaluation using distributions for exposure parameters showed that the model accurately predicted geometric (GM) blood lead levels of Palmerton and Sandy and slightly over predicted the GSD. Consideration of uncertainty in red blood cell parameters substantially inflated the GM. Future model development needs to address the correlation among parameters and the use of parameters for long-term exposure derived from short-term studies.

Dust↗
PubMed1986

Comparison of an implanted abdominal aortic counterpulsation device with the intraaortic balloon pump in a heart failure model.

The abdominal aortic counterpulsation device is a round pumping chamber with a valveless opening which is implanted retroperitoneally on the abdominal aorta. The Utah driver is connected to the device through an air conduit and is synchronized on the electrocardiographic signal to provide diastolic aortic augmentation. For comparison an intraaortic balloon was also driven by the Utah driver system. The abdominal aortic counterpulsation device (stroke volume = 30, 40 and 60 ml) and the intraaortic balloon pump (balloon volume = 20 ml) were tested in dogs with acute left ventricular failure. The abdominal aortic counterpulsation device was also tested in normal animals. In acute left ventricular failure the abdominal aortic counterpulsation device at a stroke volume of 30, 40 or 60 ml decreased left ventricular end-diastolic pressure by an average of 28.56 (p less than 0.001), 39.56 (p less than 0.001) and 44.14% (p less than 0.005), respectively; aortic end-diastolic pressure by 24.11 (p less than 0.001), 26.67 (p less than 0.001) and 19.57% (p less than 0.01); and aortic systolic pressure by 18.56 (p less than 0.002), 26.0 (p less than 0.001) and 22.43% (p less than 0.005). It increased cardiac index by 27.58 (p less than 0.02), 35.59 (p less than 0.005) and 43.42% (p less than 0.001) and it provided peak aortic diastolic augmentation of 64.5 (p less than 0.001), 69.78 (p less than 0.001) and 74.43% (p less than 0.001), respectively, above the control aortic end-diastolic pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2000

Retreatment after initial laser in situ keratomileusis.

PURPOSE: To report the results of laser in situ keratomileusis (LASIK) retreatment in patients with primary undercorrection and with postoperative regression and to assess the efficacy and safety of LASIK retreatment. SETTING: The Eye Institute of Utah, Salt Lake City, Utah, USA. METHODS: The prospective study included 157 eyes of 108 patients. Using the VISX Star laser, retreatments were performed for undercorrection in 43 eyes (27%) and for regression in 114 eyes (73%). The mean follow-up was 15 months (range 6 to 28 months) after the initial surgery and 10 months (range 3 to 25 months) after the repeat LASIK procedure. RESULTS: Overall, the mean spherical equivalent (SE) was -6.11 +/- 2.35 diopters (D) (range -1.87 to -15.00 D) before LASIK and -1.28 +/- 0.57 D (range -0.50 to -3.25 D) prior to retreatment. At the last visit, it was -0.23 +/- 0.41 D (range -2.55 to 1.13 D). One hundred fifty-three eyes (97.5%) were within +/-1.00 D of emmetropia and 128 (81.5%), within +/-0.50 D. The uncorrected visual acuity was 20/20 or better in 68.8% of eyes and 20/40 or better in 98.1%. In all eyes, the best corrected visual acuity (BCVA) improved or remained within 1 line of the pre-revision level. However, 2 eyes (1.3%) lost 2 or more lines of pre-initial LASIK BCVA. Both eyes had a preoperative SE greater than -8.00 D; corneal irregularity was the cause of the decrease in vision. CONCLUSIONS: Several conclusions can be drawn from this study. First, LASIK retreatment is effective and safe for correcting undercorrection and regression after initial LASIK, and a good visual outcome is expected. Second, in most eyes, regression occurs within 6 months after the initial LASIK. However, regression can develop up to 2 years after LASIK. Third, multiple retreatments will be required in some patients. The outcome in these cases is promising.

Adult↗
PubMed2000

Dysphotopsia in phakic and pseudophakic patients: incidence and relation to intraocular lens type(2).

PURPOSE: To determine the relationship between various intraocular lens (IOL) types and the incidence of unwanted light images. SETTING: The Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: A telephone questionnaire was administered to 302 postoperative patients who had received 1 of 6 commonly used IOLs between January and September 1998. Patients were included only if they had uneventful cataract surgery, no additional ocular pathology, and a postoperative best corrected visual acuity of 20/25 or better. A control group of 50 patients with the diagnosis of presbyopia only also participated in the questionnaire. Patients reported on incidence of glare, light sensitivity, and unwanted images. The data were analyzed for statistically significant relationships between incidence of photopsias and IOL type. RESULTS: The AcrySof 5.5 mm, AcrySof 6.0 mm, and SI-40 groups reported significantly more unwanted images than the control group (P =.0014). The 2 AcrySof groups also reported a greater incidence of light to the side causing a central flash, and the SI-40 group, a higher incidence of glare. The control group was more likely to experience symptoms of glare than any pseudophakic group. Overall, a mean of 49% of patients reported some light-related phenomenon postoperatively. The majority in all groups reported being satisfied with their eyesight despite the light-related problems. CONCLUSIONS: A significant number of pseudophakic patients reported symptoms of dysphotopsia. Patients who received an acrylic IOL with flattened edges were at increased risk of experiencing images associated with edge reflections. The SI-40 lens group, although less than the AcrySof groups, reported a higher incidence of glare than the non-AcrySof groups; however, it also had the highest number of patients still driving at night. The phakic population commonly experienced glare reported as more severe than several of the IOL groups.

Aged↗