Publications by authors named "Calogero D"

29 Publications

  • Page 1 of 1

Experimental and analytical quantification of light scattering from vacuoles in intraocular lenses.

J Cataract Refract Surg 2020 May;46(5):762-773

From the Optical Therapeutics and Medical Nanophotonics Laboratory, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health (Spiezio, Ilev), and Office of Device Evaluation, Center for Devices and Radiological Health (Walker, Calogero), U.S. Food and Drug Administration, Silver Spring, Maryland, USA.

Purpose: To develop an advanced test methodology for quantification of scattered light from intraocular lenses (IOLs) and to evaluate the correlation between IOL vacuole characteristics and measured scattered light.

Setting: U.S. Food and Drug Administration, Optical Therapeutics and Medical Nanophotonics Laboratory, Silver Spring, Maryland, USA.

Design: Experimental and analytical study.

Methods: Twenty-four IOLs containing vacuoles were evaluated using a digital microscopy approach for identifying and characterizing the vacuoles present. A scanning light scattering profiler (SLSP) was used to evaluate and quantify the amount of scattered light from each IOL and from a 25th control IOL without any vacuoles. A variety of IOLs and vacuoles were also modeled in a Zemax simulation of the SLSP, and the simulated scattered light was modeled.

Results: The scattered light as measured with SLSP was well correlated with vacuole characteristics, specifically density and size, as measured under the digital microscope for the 24 vacuole-containing IOLs. Additional correlations were found between vacuole sizes, orientations, and the angle at which light was scattered most severely. These correlations were also present in the Zemax model.

Conclusions: Vacuole optical characteristics can be well correlated with measured scatter, demonstrating an ability to predict scattered light based solely on microscope evaluation. Furthermore, the quantitative amount of scatter predicted with Zemax simulations trended closely with the experimentally measured trends.
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http://dx.doi.org/10.1097/j.jcrs.0000000000000167DOI Listing
May 2020

Quantitative Multiparameter Evaluation of Vacuoles in Intraocular Lenses Employing a High-Magnification Digital Microscopy Method.

J Ophthalmol 2019 4;2019:7929014. Epub 2019 Aug 4.

Optical Therapeutics and Medical Nanophotonics Laboratory, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland 20993, USA.

As small imperfections with micrometric sizes, fluid-filled vacuoles, also referred to as glistenings, in intraocular lenses (IOLs) have been known to induce significant unwanted light scattering that in several cases presumably cause complaints and sometimes lead to IOL explantation and replacement. This unwanted scatter is of particular concern for patients viewing bright light in reduced-light conditions such as when driving at night, as the scattered light toward the retina can cause temporary blindness. In this study, we have developed and implemented an accurate test methodology based on a high-magnification digital microscopy approach for quantitative multiparameter evaluation and classification of IOL vacuoles depending on their critical optical characteristics including vacuole size, density, shape, and orientation within the IOL material. Using the multiparameter database developed by evaluating vacuole characteristics, we established a classification grading system that can be used to evaluate vacuole effects on light scattering.
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http://dx.doi.org/10.1155/2019/7929014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6701293PMC
August 2019

Noncontact method for sensing thickness and refractive index of intraocular lens implants using a self-calibrating dual-confocal laser caliper.

J Biomed Opt 2018 06;23(6):1-6

US Food and Drug Administration, Center for Devices and Radiological Health, Office of Science and E, United States.

We present a fiber-optic dual-confocal laser caliper method for noncontact high-precision sensing and measuring thickness and refractive index of intraocular lens (IOL) implants. The principle of the method is based on sensing and measuring the confocal intensity response of the laser beam reflection from the opposite object surfaces, which provides the advanced feature of having no limitations on the object shape, thickness, and transparency. Using single-mode optical fibers and a 658-nm laser source, the thickness measurement accuracy was assessed to be as high as 5  μm. In addition, refractive index of a transparent object with thickness smaller than the working distance of the focusing lenses can be measured. The thickness and refractive index of a planoconvex IOL were measured with a high accuracy.
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http://dx.doi.org/10.1117/1.JBO.23.6.067004DOI Listing
June 2018

Scanning Light Scattering Profiler (SLPS) Based Methodology to Quantitatively Evaluate Forward and Backward Light Scattering from Intraocular Lenses.

J Vis Exp 2017 06 6(124). Epub 2017 Jun 6.

Optical Therapeutics and Medical Nanophotonics Laboratory, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration.

The scanning light scattering profiler (SLSP) methodology has been developed for the full-angle quantitative evaluation of forward and backward light scattering from intraocular lenses (IOLs) using goniophotometer principles. This protocol describes the SLSP platform and how it employs a 360° rotational photodetector sensor that is scanned around an IOL sample while recording the intensity and location of scattered light as it passes through the IOL medium. The SLSP platform can be used to predict, non-clinically, the propensity for current and novel IOL designs and materials to induce light scatter. Non-clinical evaluation of light scattering properties of IOLs can significantly reduce the number of patient complaints related to unwanted glare, glistening, optical defects, poor image quality, and other phenomena associated with the unintended light scattering. Future studies should be conducted to correlate SLSP data with clinical results to help identify which measured light scatter is most problematic for patients that have undergone cataract surgery subsequent to IOL implantation.
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http://dx.doi.org/10.3791/55421DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5608261PMC
June 2017

Special Report: American Academy of Ophthalmology Task Force Consensus Statement for Extended Depth of Focus Intraocular Lenses.

Ophthalmology 2017 01 13;124(1):139-141. Epub 2016 Oct 13.

Food and Drug Administration, Center for Devices and Radiological Health, Silver Spring, Maryland.

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http://dx.doi.org/10.1016/j.ophtha.2016.09.039DOI Listing
January 2017

Confocal laser method for quantitative evaluation of critical optical properties of toric intraocular lenses.

J Cataract Refract Surg 2016 Mar;42(3):455-61

From the Optical Therapeutics and Medical Nanophotonics (Walker, James, Song, Ilev), Office of Science and Engineering Laboratories, and the Office of Device Evaluation (Walker, Calogero), Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland, USA.

Purpose: To present a proof-of-concept study on the development and implementation of an innovative confocal laser method platform for precise quantitative evaluation of critical optical properties unique to toric intraocular lenses (IOLs).

Setting: U.S. Food and Drug Administration, Optical Therapeutics and Medical Nanophotonics Laboratory, Silver Spring, Maryland, USA.

Design: Experimental study.

Methods: The optical properties of hydrophobic toric IOLs were evaluated with a confocal laser method that was modified to isolate the 2 planes of focus that are observed with toric IOLs.

Results: The results show the confocal laser method has the potential to measure the orthogonally separated optical powers and then calculate them to the commonly referenced spherical equivalent and cylinder powers of toric IOLs with high accuracy (≤1 μm of focal length measurement). Furthermore, the proposed confocal laser method design includes a new component for precise differentiation of the 2 focal planes and isolation of the 2 focal points, and thus for accurate measurement of the anterior cylinder axis of toric IOLs.

Conclusion: The modifications to the confocal laser method platform enabled the quantitative evaluation of optical properties attributed to toric IOLs.

Financial Disclosure: None of the authors has a financial or proprietary interest in any material or method mentioned.
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http://dx.doi.org/10.1016/j.jcrs.2015.09.031DOI Listing
March 2016

A novel full-angle scanning light scattering profiler to quantitatively evaluate forward and backward light scattering from intraocular lenses.

Rev Sci Instrum 2015 Sep;86(9):095004

Optical Therapeutics and Medical Nanophotonics Laboratory, Office of Science and Engineering Laboratories, U.S. Food and Drug Administration, Silver Spring, Maryland 20993, USA.

Glare, glistenings, optical defects, dysphotopsia, and poor image quality are a few of the known deficiencies of intraocular lenses (IOLs). All of these optical phenomena are related to light scatter. However, the specific direction that light scatters makes a critical difference between debilitating glare and a slightly noticeable decrease in image quality. Consequently, quantifying the magnitude and direction of scattered light is essential to appropriately evaluate the safety and efficacy of IOLs. In this study, we introduce a full-angle scanning light scattering profiler (SLSP) as a novel approach capable of quantitatively evaluating the light scattering from IOLs with a nearly 360° view. The SLSP method can simulate in situ conditions by controlling the parameters of the light source including angle of incidence. This testing strategy will provide a more effective nonclinical approach for the evaluation of IOL light scatter.
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http://dx.doi.org/10.1063/1.4930179DOI Listing
September 2015

Special Commentary: Food and Drug Administration and American Academy of Ophthalmology Sponsored: Developing Novel End Points for Premium Intraocular Lenses Workshop.

Ophthalmology 2015 Jul 18;122(7):1522-31. Epub 2015 Apr 18.

Office of Device Evaluation, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, Maryland. Electronic address:

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http://dx.doi.org/10.1016/j.ophtha.2015.02.038DOI Listing
July 2015

Assessing the effect of laser beam width on quantitative evaluation of optical properties of intraocular lens implants.

J Biomed Opt 2014 May;19(5):055004

Optical Therapeutics and Medical Nanophotonics Laboratory, Office of Science and Engineering Laboratories, U.S. Food and Drug Administration, Silver Spring, Maryland 20993.

The design and manufacture of intraocular lenses (IOLs) depend upon the identification and quantitative preclinical evaluation of key optical properties and environmental parameters. The confocal laser method (CLM) is a new technique for measuring IOL optical properties, such as dioptric power, optical quality, refractive index, and geometrical parameters. In comparison to competing systems, the CLM utilizes a fiber-optic confocal laser design that significantly improves the resolution, accuracy, and repeatability of optical measurements. Here, we investigate the impact of changing the beam diameter on the CLM platform for the evaluation of IOL dioptric powers. Due to the Gaussian intensity profile of the CLM laser beam, the changes in focal length and dioptric power associated with changes in beam diameter are well within the tolerances specified in the ISO IOL standard. These results demonstrate some of the advanced potentials of the CLM toward more effectively and quantitatively evaluating IOL optical properties.
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http://dx.doi.org/10.1117/1.JBO.19.5.055004DOI Listing
May 2014

Impact of environmental temperature on optical power properties of intraocular lenses.

Appl Opt 2014 Jan;53(3):453-7

Optical power properties of lenses and materials in general can be influenced by thermal changes of the material and surrounding medium. In the case of an intraocular lens (IOL) implant, the spherical power (SP), cylinder power, (CP), astigmatism, and spherical aberration are the critical fundamental properties that can significantly impact its efficacy. Directly evaluating how changes in temperature can affect these optical properties may show the importance of considering temperature when evaluating IOL optical characteristics. In this paper, we present a quantitative study on evaluating the impact of environmental temperature changes on IOL fundamental optical properties by testing IOL samples with different materials (e.g., hydrophobic and hydrophilic) and designs (e.g., monofocal and toric) to better encompass types of IOLs in conventional use today. The results from this study demonstrate that significant changes are observed as temperatures are changed from room temperature (20°C) to slightly above body temperature (40°C). Findings indicate that evaluating optical properties at arbitrary temperatures could significantly affect the characterization of IOLs that are already near the tolerance thresholds.
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http://dx.doi.org/10.1364/AO.53.000453DOI Listing
January 2014

Detecting endotoxin contamination of ophthalmic viscosurgical devices: intracameral versus intravitreal assays in rabbits.

Ophthalmology 2012 Jul 11;119(7):e11-8. Epub 2012 May 11.

Food and Drug Administration, ORISE contractor, Silver Spring, Maryland 20993-0002, USA.

Objective: To compare the sensitivities of intracameral and intravitreal assays in the rabbit model to determine the relative adequacy of these methods in detecting bacterial endotoxin contamination of ophthalmic viscosurgical devices (OVDs).

Design: Experimental, randomized animal study.

Participants: Twenty New Zealand white rabbits.

Methods: Rabbits were randomized into 4 groups to receive a cohesive or a dispersive OVD via intracameral or intravitreal injection. All 40 treated eyes (10 eyes of 5 animals in each group) received bilateral injection of OVD spiked with bacterial endotoxin at 7.0 endotoxin units/ml. All eyes were evaluated by slit-lamp biomicroscopy for inflammatory response at 3, 6, 9, 24, 48, and 72 hours after exposure. Eyes that received intravitreal injection were also dilated at 24, 48, and 72 hours and were re-examined by slit-lamp biomicroscopy and by indirect ophthalmoscopy.

Main Outcome Measures: Conjunctival inflammation, anterior chamber (AC) flare, cells and fibrin, vitreous haze and cells, iridal hyperemia, corneal clouding, lens opacities, and onset times.

Results: Intracamerally injected eyes frequently showed conjunctival congestion, AC cells and flare, iridal hyperemia, and fibrin within 6 hours. Up to 80% showed AC cells and flare at 9 hours, and up to 70% showed fibrin at 24 hours. These signs diminished within 48 hours. Fibrin and cells also were seen on the lens surface of most of the eyes. Intravitreally injected eyes showed no signs of inflammation within 24 hours, other than some conjunctival inflammation. After the 24-hour time point, in addition to some conjunctival inflammation, some other signs of inflammation were observed infrequently in the intravitreally injected eyes, including minor vitreous cell reaction in 2 eyes. Although there was 1 dispersive OVD-treated eye with cells and fibrin on the lens capsule at 48 hours, no aqueous cells or flare were seen in the AC of any intravitreally injected eyes at any time during the course of the study.

Conclusions: The rabbit intravitreal assay, when limited to 72 hours, does not seem to have adequate sensitivity to detect endotoxin reliably in OVDs.
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http://dx.doi.org/10.1016/j.ophtha.2012.04.005DOI Listing
July 2012

Rabbit ocular reactivity to bacterial endotoxin contained in aqueous solution and ophthalmic viscosurgical devices.

Ophthalmology 2012 Jul 11;119(7):e4-e10. Epub 2012 May 11.

Food and Drug Administration, Oak Ridge Institute for Science and Education contractor, Silver Spring, Maryland 20993-0002, USA.

Objective: To describe the ocular reactivity of the rabbit to bacterial endotoxin contained in an aqueous medium and in a cohesive and a dispersive ophthalmic viscosurgical device (OVD).

Design: Experimental, randomized animal study.

Participants: Seventy-five New Zealand white rabbits.

Methods: This study was performed using 75 rabbits to evaluate the ocular reactivity to bacterial endotoxin contained in Dulbecco's phosphate-buffered saline (DPBS), a cohesive OVD, and a dispersive OVD. For each test material, 25 rabbits were randomized into 5 groups and were exposed to the test material containing 0.75 endotoxin units (EU), 0.25 EU, 0.08 EU, and 0.02 EU of endotoxin or the vehicle control. The rabbits in each group received bilateral intracameral injection of 0.05 ml of the same test material. All eyes were examined by slit-lamp biomicroscopy at baseline, 3, 6, 9, 24, 48, and 72 hours after injection. At 24 and 72 hours, slit-lamp biomicroscopy (and additionally indirect ophthalmoscopy) was performed through dilated pupils.

Main Outcome Measures: Corneal clouding, anterior chamber (AC) flare, cells and fibrin, vitreous haze and cells, cells and fibrin on lens surface, lens opacities, and onset time.

Results: The inflammation seen after exposure to the 3 endotoxin-spiked materials followed the same general time course. Anterior chamber cells, flare, iris hyperemia, and conjunctival congestion were seen as early as 3 hours. They started to diminish after 6 hours (DPBS eyes) and 9 hours (OVDs) and were not detectable at 48 and 72 hours, respectively. The AC inflammation was more severe in the OVD eyes than in the DPBS eyes. Anterior chamber fibrin was seen in the OVD eyes only, which persisted through 72 hours in many eyes. A trend toward a dose-response relationship was seen for AC cells and flare and the presence of cells and fibrin on the lens surface in all 3 treatment groups in the first 24 hours.

Conclusions: Inflammation was seen after intracameral injection of as little as 0.02 and 0.08 EU in OVD and DPBS eyes, respectively. Observed responses to intracamerally injected endotoxin in OVDs were more severe and of longer duration than those in aqueous medium.
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http://dx.doi.org/10.1016/j.ophtha.2012.04.006DOI Listing
July 2012

Evaluation of intraocular reactivity to organic contaminants of ophthalmic devices in a rabbit model.

Ophthalmology 2012 Jul 11;119(7):e24-9. Epub 2012 May 11.

Food and Drug Administration Oak Ridge Institute for Science and Education contractor, Silver Spring, Maryland 20993-0002, USA.

Objective: To evaluate the intraocular reactivity to organic contaminants of ophthalmic devices in the rabbit.

Design: Experimental animal study.

Participants: Fifty New Zealand white rabbits.

Methods: The rabbits were allocated to 10 groups of 5 each to receive 2 different doses of human albumin and nonhuman nucleic acids and their respective vehicle controls, a denatured cohesive ophthalmic viscosurgical device (OVD) and a denatured dispersive OVD and their respective nondenatured controls. All 10 eyes in each treatment group received bilateral intracameral injection of the test materials. All the eyes in the study were examined by slit-lamp biomicroscopy at baseline and 6, 9, 24, 48, and 72 hours. Pachymetry was also performed on eyes exposed to albumin, protein vehicle control, and the OVDs at these time points.

Main Outcome Measures: Corneal thickness, grade of corneal clouding, anterior chamber (AC), cells, flare and fibrin, iridal hyperemia, cell and fibrin on lens surface, and onset time.

Results: There were no inflammatory signs in any eyes exposed to human albumin. Anterior chamber cells (1+ to 3+) and flare and fibrin (1+ to 2+), along with cells and fibrin on the lens surface, were seen in the eyes exposed to the nucleic acid samples, and they resolved in 24 hours. Mild (mostly 1+) conjunctival congestion, cells, flare, and fibrin were seen in a few eyes exposed to the 2 denatured OVDs and their controls, with the response durations being shorter in the denatured OVD eyes (24 hours) than in the nondenatured OVD eyes (48 hours). Anterior chamber inflammation was generally observed in fewer denatured OVD eyes than in nondenatured OVD eyes, particularly the dispersive OVD eyes.

Conclusions: Intracameral injection of human albumin protein did not cause ocular inflammation. Nucleic acid intracamerally injected into rabbit eyes caused acute inflammation that quickly resolved. Cohesive and dispersive OVD denatured by drying and steam sterilization alone did not cause ocular inflammation.
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http://dx.doi.org/10.1016/j.ophtha.2012.04.007DOI Listing
July 2012

Rabbit intraocular reactivity to endotoxin measured by slit-lamp biomicroscopy and laser flare photometry.

Ophthalmology 2012 Jul 11;119(7):e19-23. Epub 2012 May 11.

National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA.

Objective: To evaluate the ocular reactivity of the rabbit to an intracameral injection of a dispersive ophthalmic viscosurgical device (OVD) containing various levels of bacterial endotoxin using slit-lamp biomicroscopy and laser flare photometry.

Design: Experimental, randomized, masked animal study.

Participants: Thirty Dutch-Belted rabbits.

Methods: The rabbits were randomized into 6 groups to receive 0.05 ml of a hydroxypropyl methylcellulose-based dispersive OVD to which had been added one of 5 different doses of bacterial endotoxin ranging from 0.02 to 1.4 endotoxin units (EUs) or a vehicle control to both eyes. The eyes were evaluated for anterior segment inflammation at baseline and 3, 6, 9, 24, 48, and 72 hours after injection using slit-lamp biomicroscopy and laser flare photometry.

Main Outcome Measures: Corneal clarity and anterior chamber (AC) inflammation.

Results: All the corneas remained clear throughout the study. Anterior chamber cells were seen at 6, 9, and 24 hours in 60% to 100% of the eyes intracamerally injected with endotoxin-containing OVD, and the response declined rapidly after 24 hours. A dose-response effect was seen between the concentration of endotoxin and the AC cell response. The aqueous flare response in eyes injected with the 2 highest doses of endotoxin was significantly greater (P<0.05) than that of controls. The amounts of fibrin observed in the AC were random, with no apparent dose-response effect seen. The flare values as obtained by laser flare photometry were consistent with the slit-lamp biomicroscopy flare findings up to grade 3+. However, the increase in laser flare value seemed to level off in eyes with more than 3+ flare. Neither measure of flare correlated with endotoxin level.

Conclusions: Among the parameters evaluated in this study, the AC cell response, evaluated by slit-lamp biomicroscopy and graded using a standard grading system, was found to be the most reliable indicator of the amount of endotoxin in the dispersive OVD. The use of laser flare photometry alone does not seem to be useful in detecting an ocular response to endotoxin contamination in OVDs.
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http://dx.doi.org/10.1016/j.ophtha.2012.04.004DOI Listing
July 2012

The Food and Drug Administration's Proactive toxic anterior segment syndrome Program.

Ophthalmology 2012 Jul 11;119(7):1297-302. Epub 2012 May 11.

Food and Drug Administration, Center for Devices and Radiological Health, Office of Device Evaluation, Division of Ophthalmic, Neurological, and Ear, Nose, and Throat Devices, Silver Spring, Maryland 20993, USA.

Toxic anterior segment syndrome (TASS) is a rare inflammatory condition usually observed within the first 48 hours after uncomplicated anterior segment surgery. Over the decades since its initial description, a number of TASS outbreaks have been reported. For a few of these outbreaks, the inciting factors were identified, but for the majority, the precipitating factors were often postulated but not confirmed. In light of the limitations identified in these outbreak investigations, the Food and Drug Administration's (FDA's) Center for Devices and Radiological Health staff has embarked on a number of activities aimed at mitigating medical device-related TASS outbreaks. Under the FDA-designed Proactive TASS Program (PTP), FDA scientists have conducted animal studies to better explore the inflammatory potential of suspected ophthalmic device contaminants implicated in prior cases of TASS. For contaminants displaying a TASS-like reaction in these animal models, the FDA scientists have developed analytic test methods to measure the level of those contaminants in or on ophthalmic devices. Moreover, FDA researchers have developed methods to better capture the clinical information necessary to assist investigations of potential future outbreaks. Last, the FDA has partnered with the Centers for Disease Control and Prevention to facilitate a potential TASS investigation, including expediting the analysis of potentially contaminated medical devices. The PTP is an example of the FDA proactively developing test methods and disease surveillance methods geared toward protecting the public's health.
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http://dx.doi.org/10.1016/j.ophtha.2012.04.008DOI Listing
July 2012

An investigation of enzymatic detergents as a potential cause of toxic anterior segment syndrome.

Ophthalmology 2012 Jul 11;119(7):e30-5. Epub 2012 May 11.

Food and Drug Administration, Oak Ridge Institute for Science and Education (ORISE) contractor, Silver Spring, Maryland 20993-0002, USA.

Objective: To investigate whether enzymatic detergents used in cleaning ophthalmic surgical instruments can cause toxic anterior segment syndrome (TASS)-like responses in a rabbit model.

Design: Randomized, investigator-masked, controlled experimental animal study.

Participants: Thirty-five New Zealand white rabbits.

Methods: The rabbit eyes were randomized into 7 treatment groups to receive intracameral injection of 1 of 3 different doses of Medline Dual Detergent or Enzol Detergent, or sterile limulus amoebocyte lysate reagent water as a control. The eyes were evaluated for anterior segment inflammation at baseline and at 1, 3, 6, 24, 48, and 72 hours after treatment by slit-lamp biomicroscopy.

Main Outcome Measures: Anterior chamber (AC) inflammation, including cells, flare, fibrin, and iris injection; time course of inflammation; and residual detergent levels in luminated instruments.

Results: Moderate to marked injection of the iris vessels was seen as early as 1 hour after treatment with the enzymatic detergents in 41 of 60 eyes, with the response being more severe in the Enzol Detergent-exposed eyes. Severe iris hemorrhages were accompanied by blood in the AC in 13 eyes, which usually persisted through 72 hours, with an associated increase in AC cell and flare. Corneal haze was present in 52 of 56 eyes 1 hour after treatment, but was mild and resolved within 24 hours in all but the Enzol 4.5%-exposed eyes. Median AC cell and flare peaked at 6 hours and resolved by 48 hours.

Conclusions: Enzymatic detergents caused a severe but unusual response from the iris when injected intracamerally into rabbit eyes. This response has not been reported in humans with TASS. The time course of inflammation was faster (peak at 6 hours) and resolved more quickly (within 48 hours) than TASS. Simulated cleaning and extraction studies indicate that the level of residual detergent to which a patient could be exposed is significantly less than the lowest dose used in this study. Because that low dose caused no significant observations other than injection of the iris vessels, these results do not support residual enzymatic detergents on surgical instruments as a cause for TASS.
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http://dx.doi.org/10.1016/j.ophtha.2012.04.016DOI Listing
July 2012

Evaluation of intraocular reactivity to metallic and ethylene oxide contaminants of medical devices in a rabbit model.

Ophthalmology 2012 Jul 11;119(7):e36-42. Epub 2012 May 11.

Food and Drug Administration, Center for Devices and Radiological Health, Office of Device Evaluation, Division of Ophthalmic, Neurological, and Ear, Nose, and Throat Devices, Silver Spring, Maryland 20993-0002, USA.

Objective: To evaluate the intraocular reactivity to metallic and ethylene oxide (EO) contaminants of ophthalmic devices in rabbits.

Design: Two experimental animal studies.

Participants: Thirty-five New Zealand white rabbits.

Methods: A metallic exposure study and an EO exposure study were performed. In the first study, both eyes of 25 rabbits were equally allocated to intracameral injections of alumina 0.2 μg, alumina 20 μg, copper sulfate 0.4 μg, copper sulfate 20 μg, or an aqueous control. In the second study, 10 rabbits were allocated (5 per group) to receive intracamerally an ophthalmic viscosurgical device (OVD) exposed to EO or not exposed to EO (control). All eyes were examined by slit lamp at baseline and 3, 6, 9, 24, 48, and 72 hours after exposure, with dilated indirect ophthalmoscopy being performed at 24 and 72 hours. Tonometry was performed only in the first study.

Main Outcome Measures: Grade of corneal clouding, anterior chamber (AC) flare, AC cells, AC fibrin, iridal hyperemia, cell and fibrin on the lens surface, vitreous haze and cells, lens opacities, intraocular pressure, and onset time.

Results: For metallic compounds at the study's low doses, mean inflammatory grades were 0.2 or less above the control for all responses at all time points. For the high-dose alumina, mean inflammatory grades peaked at 6 to 9 hours at 0.5 to 0.7 above the control responses for conjunctival congestion, iris hyperemia, AC cells, flare, and fibrin and declined over the remaining time points. For the high-dose copper sulfate, mean inflammatory grades peaked between 3 and 24 hours at 1.2 to 1.8 above the control responses for conjunctival congestion, iris hyperemia, AC cells, flare, fibrin, and corneal clouding, then subsequently declined. The intraocular pressure changes appeared significant for only high-dose copper sulfate, with mean declines of 4.3 to 7.5 mmHg at 6 to 72 hours. No clinically meaningful differences in ocular inflammation were observed between the OVD exposed to EO and the OVD not exposed to EO.

Conclusions: Alumina and copper sulfate did not cause clinically meaningful ocular inflammation at the low study levels (levels expected with ophthalmic devices). Ethylene oxide exposure of an OVD was not associated with inflammation.
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http://dx.doi.org/10.1016/j.ophtha.2012.04.009DOI Listing
July 2012

Quantification of glistenings in intraocular lenses using a ballistic-photon removing integrating-sphere method.

Appl Opt 2011 Dec;50(35):6461-7

Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, Maryland 20993, USA.

An alternative method for quantification of glistenings in intraocular lenses (IOLs) using an integrating sphere with an adjustable back aperture to remove ballistic photons is presented. Glistenings in soft IOLs have been known for more than a decade; however, their severity and visual impact are still under investigation. A number of studies have been made to quantitatively describe glistenings in IOLs. Quantization and precise grading of IOLs will provide needed information to evaluate the severity and visual impact of glistenings in patients. We investigated the use of a simple modification of an integrating-sphere method to eliminate ballistic photons to quantitatively measure scattered light from glistenings in IOLs. The method described in this paper provides a simple and effective way to quantitatively characterize glistenings in vitro. It may be especially useful to quantify scattering associated with low-grade glistenings where the density of the scattering centers is low. Finally, the modified integrating-sphere method may also be generally applicable to quantitatively characterize scattering from other optical media.
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http://dx.doi.org/10.1364/AO.50.006461DOI Listing
December 2011

Noncontact common-path Fourier domain optical coherence tomography method for in vitro intraocular lens power measurement.

J Biomed Opt 2011 Dec;16(12):126005

U.S. Food and Drug Administration, Center for Devices and Radiological Health, 10903 New Hampshire Avenue, Silver Spring, Maryland 20993, USA.

We propose a novel common-path Fourier domain optical coherence tomography (CP-FD-OCT) method for noncontact, accurate, and objective in vitro measurement of the dioptric power of intraocular lenses (IOLs) implants. The CP-FD-OCT method principle of operation is based on simple two-dimensional scanning common-path Fourier domain optical coherence tomography. By reconstructing the anterior and posterior IOL surfaces, the radii of the two surfaces, and thus the IOL dioptric power are determined. The CP-FD-OCT design provides high accuracy of IOL surface reconstruction. The axial position detection accuracy is calibrated at 1.22 μm in balanced saline solution used for simulation of in situ conditions. The lateral sampling rate is controlled by the step size of linear scanning systems. IOL samples with labeled dioptric power in the low-power (5D), mid-power (20D and 22D), and high-power (36D) ranges under in situ conditions are tested. We obtained a mean power of 4.95/20.11/22.09/36.25 D with high levels of repeatability estimated by a standard deviation of 0.10/0.18/0.2/0.58 D and a relative error of 2/0.9/0.9/1.6%, based on five measurements for each IOL respectively. The new CP-FD-OCT method provides an independent source of IOL power measurement data as well as information for evaluating other optical properties of IOLs such as refractive index, central thickness, and aberrations.
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http://dx.doi.org/10.1117/1.3660313DOI Listing
December 2011

Testing the dioptric power accuracy of exact-power-labeled intraocular lenses.

J Cataract Refract Surg 2009 Nov;35(11):1995-9

University of California, Los Angeles, California, USA.

Purpose: To test the accuracy of exact-power-labeled intraocular lenses (IOLs) in a limited independent study.

Setting: U.S. Food and Drug Administration Optical Testing Lab.

Methods: Hydrophilic acrylic IOLs were measured using a new confocal laser method for dioptric power measurement per International Organization for Standards standard 11979-2 and American National Standards Institute standard Z80.7. Some of the IOLs were measured at 22 degrees C and 35 degrees C.

Results: For the 18 IOLs tested, the mean difference between the manufacturer's exact labeled power (D(EL)) and the power measured in the study (D(M)) was 0.18 diopter (D) +/- 0.12 (SD) and between D(M) and the usual normal rounded-off (0.50 D steps) dioptric power (D(UL)) labeling, 0.23 +/- 0.09 D (difference 0.05 D). For 15.00 to 20.0 D IOLs, the mean difference between D(M) and D(EL) was 0.08 +/- 0.05 D and between D(M) and D(UL), 0.17 +/- 0.06 D (difference 0.09 D). For IOLs of 20.00 D or greater, the mean difference between D(M) and D(EL) was 0.24 +/- 0.11 D and between D(M) and D(UL), 0.27 D +/- 0.08 D (difference 0.03 D). When the IOL hydration temperature increased from 22 degrees C to 35 degrees C (4 IOLs tested), the IOL power increase on average was approximately 0.13 D.

Conclusions: The small improvement in power-prediction accuracy for exact-power-labeled IOLs decreased in IOLs of 20.00 D or greater. For IOLs of 15.00 to 20.00 D, the increased accuracy (+/-0.09 D) was statistically significant and could increase predictability of postoperative refractions. Acrylic dioptric power was directly proportional to temperature.
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http://dx.doi.org/10.1016/j.jcrs.2009.06.021DOI Listing
November 2009

Assessment of visual performance in the evaluation of new medical products.

Drug Discov Today Technol 2007 ;4(2):55-61

Food and Drug Administration, Center for Devices and Radiological Health, Office of Device Evaluation, Division of Ophthalmic and ENT Devices, 9200 Corporate Boulevard, Rockville, MD 20850, USA.

When evaluating how a medical product affects vision, it is important to assess how that product affects the ability to function in real life, not only the ability to read letters on a vision chart. Nevertheless, the measurement of visual acuity with a vision chart remains the primary test of the effects of medical products on vision. Here, we review efforts to identify reliable, cost-effective clinical tests to serve as surrogate measures of functional visual performance.:
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http://dx.doi.org/10.1016/j.ddtec.2007.10.009DOI Listing
July 2014

Serum levels of soluble interleukin-2 receptor (sIL-2R) in B-chronic lymphocytic leukemia.

Boll Soc Ital Biol Sper 1992 Apr;68(4):259-62

I Cattedra di Ematologia, Università di Catania.

By using an enzyme-linked immunosorbent assay, the levels of the soluble form of the interleukin-2 receptor (sIL-2R) were evaluated in the peripheral blood of 20 patients with cell chronic lymphocytic leukemia in different stages of disease and in supernatants obtained from enriched B cell suspensions. In either all serum samples or in one out of three supernatants, elevated levels of sIL-2R were found. This could indicate that the B leukemic cells release sIL-2R which in turn, for its potential capacity of binding circulating IL-2, could contribute to the abnormal immunoregulation which characterizes B-CLL. This finding, which needs further investigation, could have prognostic significance.
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April 1992

Enhanced percentage of Leu M3+DR+ and Leu M3+CD25+ cells in newly diagnosed IDDM patients.

Autoimmunity 1991 ;9(3):255-9

Second Department of Medical Pathology and Metabolic Diseases, University of Catania, Italy.

The percentage of Leu M3+DR+ and of Leu M3+CD25+ cells was determined by means of immunofluorescence analysis in a group of patients with insulin dependent diabetes mellitus (IDDM). Our results show that an increased percentage of these cells may occur in the early stage of the disease. These data provide evidence for a "phenotypical" activation of Leu M3+ cells at the onset of the disease and warrant future studies to evaluate the potential role of these cells in the pathogenesis of IDDM.
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http://dx.doi.org/10.3109/08916939109007651DOI Listing
March 1992
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