Microincisions in cataract surgery.

UNLABELLED: Improvements in phacoemulsification technology and instrumentation and intraocular lens materials and design have enabled cataract surgery to be performed through incisions smaller than 2.0 mm in external width. This evolution has occurred over time, with new challenges arising at each step of the decrease in incision size. This article reviews the current trend of using increasingly smaller incisions to perform phacoemulsification. Specifically, each facet of phacoemulsification is briefly reviewed from a historical context and then evaluated predominantly from a current perspective to better understand the development of the microincision in cataract surgery. The goal is to help the operating surgeon recognize the potential benefits as well as the potential weaknesses of the smaller incision. FINANCIAL DISCLOSURES: Proprietary or commercial disclosures are listed after the references.

Multifocal intraocular lenses: relative indications and contraindications for implantation.

UNLABELLED: This article presents an extensive overview of best clinical practice pertaining to selection and use of multifocal intraocular lenses (IOLs) currently available in the United States. Relevant preoperative diagnostic evaluations, patient selection criteria, counseling, and managing expectations are reviewed, as well as how to approach patients with underlying ocular intricacies or challenges and best practices for intraoperative challenges during planned implantation of a multifocal IOL. Managing the unhappy multifocal IOL patient if implantation has been performed is also addressed. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Effects of resynchronization strategies for lactating Holstein cows on pattern of reinsemination, fertility, and economic outcome.

The objectives were to evaluate the pattern of re-insemination, pregnancy outcomes to re-insemination in estrus and at fixed time, and economic outcomes of lactating Holstein cows submitted to three resynchronization protocols. Cows were enrolled in the Experiment at 32 ± 3 d after pre-enrollment Artificial Insemination (AI), 7 d before pregnancy diagnosis, and randomly assigned to three resynchronization protocols. All cows diagnosed not pregnant at 39 ± 3 d after pre-enrollment AI were submitted to the Cosynch72 (Day 0 GnRH, Day 7 prostaglandin F(2α), and Day 10 GnRH and fixed time AI). Cows assigned to the control treatment received no further treatment, cows assigned to the GGPG treatment received a GnRH injection on Day -7, and cows assigned to the CIDR treatment received a controlled internal drug release (CIDR) insert containing 1.38 g of progesterone from Days 0-7. Cows observed in estrus were re-inseminated on the same day. Pregnancy was diagnosed at 39 ± 3 and 67 ± 3 d after re-insemination. Costs of the resynchronization protocols were calculated for individual cows enrolled in the study and pregnancies generated were given a value of $275. The GGPG treatment resulted in the slowest (P ≤ 0.06) rate of re-insemination. Overall pregnancy per AI (P/AI) at 39 ± 3 (P = 0.50) and 67 ± 3 (P = 0.49) d after re-insemination were not affected by treatment. Although cost of the control protocol was (P < 0.01) the smallest, return per cow resynchronized was (P < 0.01) greater for GGPG and CIDR protocols. We concluded that presynchronizing the estrous cycle of cows with GnRH or treating cows with a CIDR insert during resynchronization altered the pattern of re-insemination and improved the economic return of resynchronized cows.

Prevention, diagnosis, and management of acute postoperative bacterial endophthalmitis.

This distillation of the peer-reviewed scientific literature on infection after cataract surgery summarizes background material on epidemiology, etiology, and pathogenesis, describes the roles of surgical technique and antibiotic prophylaxis in prevention, and discusses diagnostic and therapeutic interventions in cases of suspected endophthalmitis.

A method for determining the analytical form of a radionuclide depth distribution using multiple gamma spectrometry measurements.

When characterizing environmental radioactivity, whether in the soil or within concrete building structures undergoing remediation or decommissioning, it is highly desirable to know the radionuclide depth distribution. This is typically modeled using continuous analytical expressions, whose forms are believed to best represent the true source distributions. In situ gamma ray spectroscopic measurements are combined with these models to fully describe the source. Currently, the choice of analytical expressions is based upon prior experimental core sampling results at similar locations, any known site history, or radionuclide transport models. This paper presents a method, employing multiple in situ measurements at a single site, for determining the analytical form that best represents the true depth distribution present. The measurements can be made using a variety of geometries, each of which has a different sensitivity variation with source spatial distribution. Using non-linear least squares numerical optimization methods, the results can be fit to a collection of analytical models and the parameters of each model determined. The analytical expression that results in the fit with the lowest residual is selected as the most accurate representation. A cursory examination is made of the effects of measurement errors on the method.

A method for the quantitative gamma spectroscopic analysis of an unusually shaped unknown source.

An unmarked cylindrical device, identified as a ceramic high voltage capacitor, needed its radioactivity assessed so that proper disposal and shipping requirements could be met. Using a high purity germanium detector, naturally occurring 232Th was identified as the source of radioactivity. A series of point source measurements was made along the length of the item's axis using 60Co, having a gamma ray of nearly the same energy as one of the primary 232Th progeny photopeaks. These measurements were then numerically integrated to determine the response of the detector to a line source. A correction for the self shielding of the item was estimated using Monte Carlo simulations. The item was found to contain approximately 1.85 x 10(5) Bq of uniformly distributed 232Th. The overall method has application to any unusually shaped source, with point source measurements performed using an appropriate radionuclide used to establish an overall sensitivity of the detector, including its dead layer, to the radioactivity in a simple geometric representation of the object. An estimation of self shielding from Monte Carlo is then applied to that result.

Posterior capsule opacification.

PURPOSE OF REVIEW: This paper assesses the factors that contribute to the formation of an effective capsular bend as a deterrent to posterior capsule opacification. Its goal is to assist the practicing ophthalmologist in separating current understanding of this process from various working models previously proposed. RECENT FINDINGS: While a square-edge design appreciably improves resistance to posterior capsule opacification, significant factors remain under the control of the surgeon. These factors combine to form the physical and psychological barrier of a capsular bend. Innovative digital imaging has shown lens epithelial cell migration, allowing for a more rapid assessment of posterior capsule opacification resistance. A three-piece intraocular lens allows for full 360 degree capsular bend formation surrounding the optic edge; some single-piece designs may inhibit capsular bend formation. Decreasing, but not eliminating, the surviving lens epithelial cell population may diminish capsular bend strength, which may decrease resistance to posterior capsule opacification in the face of a regenerating cortex. All demographic features of clear/refractive lens exchange suggest higher rates of posterior capsule opacification than with standard cataract surgery. SUMMARY: The quality of capsular bend formation will determine how resistant an intraocular lens will be to posterior capsule opacification as a consequence of regenerating cortex. As refractive lens exchange and new accommodating intraocular lens designs become more popular, the problems of regenerating cortex will increase in magnitude.

Design of an inexpensive, flexible, shielded cave for environmental radioactivity measurements.

A graded-absorber radiation shield (cave) was designed with low cost and flexibility to lower background for counting environmental and other samples containing small amounts of radioactivity.

Forceps insertion with incisional anesthesia for Sensar intraocular lenses.

This technique to prevent self-adherence of the Sensar acrylic intraocular lens (IOL) optic during forceps insertion with wound stretch includes modifications to the 3-and-9 insertion technique to prevent difficulties that may be encountered with this phenomenon. To decrease patient sensation during IOL insertion and thus improve surgeon control, the corneal tunnel incision is directly anesthetized.

Cortical removal simplified by J-cannula irrigation.

Subincisional cortical removal is one of the more specific obstacles impeding the performance of uneventful cataract extraction. In this technique, staged use of a J-cannula irrigates the cortex remaining after phacoemulsification, particularly in the subincisional space. This is followed by standard automated aspiration. The irrigation procedure is independent of a small pupil or capsulorhexis and typically allows for complete cortical cleanup in less than 1 minute. The details of the procedure, used in more than 3000 cases, are reported.