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Biomedical subjects

L Allarakhia

Publications and source records attributed to L Allarakhia.

18 recordsLinked to original sources
PubMed1991

Ophthalmic pre-inked marking pad.

Various markers that facilitate incision and suture placement are available. The majority are used in conjunction with a surgical marking pen or ink. This report describes a new, disposable pre-inked marking pad which is conveniently packaged, easy to use, and compatible with most markers. The pad is saturated with gentian violet ink which enables an ideal transfer of inked marks from the marker to the eye or skin. The ink marks remain on the tissue for two to four hours before fading, even on wet and moist surfaces such as the cornea and sclera.

Cataract Extraction↗
PubMed1991

Irrigation, aspiration, and polishing cannula.

Aspiration of the lens cortex and capsule polishing are two important aspects of modern extracapsular cataract surgery. In this report we describe simple but useful modifications to the widely used Simcoe irrigation/aspiration cannula. The modifications consist of enlarging the aspiration port diameter from 0.3 mm to 0.4 mm and altering the terminal segment of the cannula to a sandblasted capsule polisher. The 0.4 mm diameter aspiration port reduces the incidence of capsular entrapment and allows a more efficient aspiration of cortex of varying textures. The modifications eliminate the need for a separate capsule polishing instrument and allow simultaneous lens material aspiration and capsular cleanup. These modifications can be used for any irrigation/aspiration cannula whether manually or machine operated.

Cataract Extraction↗
PubMed1991

A test for crystalline lens biocompatibility.

The current use of monkeys for testing intraocular fluids and viscoelastic materials is being questioned because of the decreasing availability and increasing cost of these scarce animals. The rabbit is an inexpensive, readily available, and convenient animal which might provide an alternative model for this purpose. In this study we have outlined the lens changes (clefts or vacuoles) that are observed in the New Zealand white rabbit as a result of toxicity to intraocular test materials. We used two viscoelastic agents, 1% sodium hyaluronate-Healon and 2% carboxymethylcellulose, and balanced salt solution to evaluate the efficacy and reproducibility of lens changes in this test study. The lens changes in each case were reproducible and could easily be graded. When used in concert with other tests, this new test can help in the preliminary evaluation of an ophthalmic material before its final clinical use in humans.

Animals↗
PubMed1990

New cystotome for intercapsular cataract procedures.

Intercapsular cataract extraction, a variation of extracapsular cataract extraction (ECCE), has recently become popular, particularly in Europe and Asia. It is gaining popularity in the United States among both phacoemulsification and planned ECCE surgeons. The initial steps in the intercapsular capsulotomy include either a linear or curvilinear opening. To facilitate anterior capsulotomy for intercapsular surgery, we developed a disposable 27-gauge cystotome with a specially designed curved configuration. This cystotome also facilitates capsulotomies in deep-set eyes, which may be difficult when standard cystotomes are used. The new cystotome has a conventional beveled tip with a 90-degree bend and a main shaft curved at a radius of 14.5 mm. When attached to a syringe this cystotome allows the surgeon a more comfortable holding position during the capsulotomy procedure.

Cataract Extraction↗
PubMed1990

New minitrephine makes lacrimal canalicular rehabilitation an office procedure.

A new minitrephine, with a stainless steel tube of 0.81-mm outer diameter, 16-mm length, a plastic hub and handle assembly for manual rotation, Luer lock attachment to either standard or specially designed 3-ml syringe with spring-assisted plunger, and an intraluminal stylet--all disposable--has been designed by us principally for opening a distally occluded lacrimal canaliculus prior to stenting with any desired implant. Local anesthesia via a nasociliary nerve block makes this an office procedure. Other potential uses include transscleral globe biopsies of suspected malignancies, intraorbital biopsies, drainage of fluid-filled spaces wherein a beveled needle evacuation might undesirably pierce the far end of the cyst--all with possible ultrasonic monitoring--or the creation of a correctly sized, round, noncollapsible passage for a Molteno valve stenting of the anterior chamber, for intractable glaucoma.

Ambulatory Care↗
PubMed1990

Eye banking: the Minnesota experience.

We present a brief report on the activities of the Minnesota Lions Eye Bank. This eye bank receives and supplies tissue to several midwestern states. In addition, it plays a vital role in providing tissue for research and training at the University of Minnesota. In association with the Department of Ophthalmology, the eye bank is also actively involved in the research and development of various corneal preservation systems. Included below is information relative to procedures used in the eye bank for the selection and collection of donor material; the decontamination, preparation, and storage of corneas; cost of eye bank services; and staff coverage. Also included is some data on the number of eyes received and processed and the eventual uses of the tissues, during the last ten years.

Corneal Transplantation↗
PubMed1990

A new ophthalmic microtrephine.

We present a new instrument designed to facilitate the microtrephination of tissues required in various ophthalmic procedures. This microtrephine is a 21-gauge stainless steel tube, 0.81 mm in diameter and 16 mm long, with a sharpened cutting end and a plastic finger-grip area to facilitate micro-rotation. A standard plastic luer hub allows the trephine to be used with a syringe, either a standard type or one with a spring-assisted plunger. Scar tissue, biopsy specimens, or abnormal inflammatory fluids can be suctioned into the syringe for subsequent pathologic examination.

Equipment Design↗
PubMed1989

New disposable cystotome for capsulorhexis.

Circular tear capsulotomy, or capsulorhexis, is becoming an increasingly popular method of anterior capsulotomy. We describe a new cystotome with a simple tip modification which is useful for performing a circular tear capsulotomy. The cystotome is a 27 gauge disposable device that is similar to a conventional cystotome used for a can-opener-type capsulotomy except for its unique but simple tip modification. The beveled tip is first bent at 90 degrees and then twisted on its main axis so that the beveled cutting edge is parallel (i.e., in the same axis) to the shaft of the cystotome. We also briefly describe its method of use.

Cataract Extraction↗
PubMed1989

Intraocular lens implantation in phakic rabbit eyes.

Three sizes (13.5 mm, 17.5 mm, and 18.5 mm) of open loop, one piece, poly(methyl methacrylate) anterior chamber intraocular lenses (IOLs) were implanted in 12 phakic rabbit eyes to evaluate the effect of the IOL on the crystalline lens and the anterior chamber. Six eyes were used as a control group. Minimum follow-up was four weeks. All the IOLs touched the crystalline lenses, and on the first postoperative day, round subcapsular lens opacities were found in all eyes in the area of IOL contact. The lens opacities became more dense with time. Only one eye in the control group showed a subcapsular opacity, which was linear rather than round. Anterior chamber inflammation was 1+ to 2+ in ten eyes (80%) in the IOL group during the first and second weeks, whereas minimal inflammatory changes occurred in the control group. These results suggest that with current IOL technology, IOL insertion in the phakic eye to correct refractive errors results in a high incidence of cataract if IOL-to-lens touch occurs.

Animals↗
PubMed1989

New silicone tipped cannulas for subretinal fluid drainage.

Two new disposable cannulas for internal drainage of subretinal fluid are described in this article. We describe a curved and a straight version consisting of plastic hubs, 20 gauge proximal and 25 gauge distal stainless steel hypodermic tubing, and soft and flexible silicone tubing overmounts. Both these cannulas facilitate atraumatic drainage of subretinal fluid through pre-existing retinal holes and tears or through a retinotomy performed during vitreoretinal microsurgery.

Body Fluids↗
PubMed1989

Preclinical evaluation of a new donor corneal trephination system.

A new corneal trephination system developed by the University of Minnesota, Department of Ophthalmology and Vision Care/3M features a corneal holder that orients and stabilizes the donor cornea during storage, transportation, and trephination. A gravity corneal punch, and disposable trephine and cutting block minimize corneal button irregularities that in other devices may contribute to postoperative astigmatism. This new system was compared with the Iowa Press by evaluating trephinated corneas on the basis of profile projectors. Buttons trephined from 10 pairs of human corneas stored in (CSM) preservation solution at 4 degrees C were evaluated by measuring diameters and edge angles and correlating them with the trephine size used. In contrast with the Iowa Press, this new system produces corneal buttons that are consistently circular, parallel-edged, and identical in size to the trephine used.

Analysis of Variance↗
PubMed1989

A new cannula for nucleus hydrodissection.

This disposable 25-gauge cannula has a specially designed distal segment which facilitates crystalline lens nucleus hydrodissection or viscodissection. The injection of a fluid or viscous material creates a cleavage plane between the nucleus and cortex or capsule, thus facilitating extraction of the nucleus. The flattened, smooth, cannulated tip allows easier insertion and manipulation under the capsule.

Cataract Extraction↗
PubMed1987

Soft intraocular lenses.

An in-depth review of the current status of soft intraocular lenses (IOLs) is presented. We have outlined the historical aspects of IOL development from polymethylmethacrylate material to newer soft polymers such as silicones and hydrogels. Chemical, physical, and biomaterial properties as well as the advantages and disadvantages of these materials and lenses are discussed. Clinical results from international investigators are presented, along with some thoughts about future trends in small incision cataract surgery and IOL substitutes.

Humans↗
PubMed1987

Neodymium:YAG laser interaction with Alcon IOGEL hydrogel intraocular lenses: an in vitro toxicity assay.

The objective of this study was to determine the potential toxicity generated by the interaction of the Nd:YAG laser and Alcon IOGEL intraocular hydrogel lens material. The IOGEL lens is composed of poly 2-hydroxyethylmethacrylate, containing 38% water, previously shown to be highly biocompatible in a wide range of tissue culture and implantation experiments. In this study, intraocular lenses (IOLs) immersed in serum-free cell culture medium were purposely exposed to exaggerated doses of laser energy to cause extensive damage. An IOLAB polymethylmethacrylate (PMMA) lens served as a control lens material. The resultant solutions were assayed for cytotoxicity in a bioassay system using fourth passage human corneal endothelial cells. No cytotoxicity was seen in the bioassay for the IOGEL hydrogel IOLs or the PMMA control IOL at any laser range/dosage tested over a 72-hour incubation period. Hydrogel lenses exhibited decreasing yellowing with decreasing energy levels, and no lens discoloration was apparent at the lowest level of irradiation, 5 mJ/50 laser bursts; the PMMA control lens exhibited moderate yellowing at 15 mJ/50 bursts. Lens marking was moderate for all IOGEL IOLs; the PMMA lens marking was severe at the power level tested.

Cataract Extraction↗
PubMedDate not supplied

Spontaneous choledocoduodenal fistula--due to chronic duodenal ulcer.

A case of spontaneous choledocoduodenal fistula due to penetrating posterior duodenal ulcer is reported. The only presenting symptoms were pain and vomiting. There was no fever or recurrent jaundice which is usually expected in such a condition. The radiological findings included barium and air in the biliary tract. Biliary fistula are not uncommon. Although external biliary fistulae are seldom seen in present times, internal biliary fistulae are not a rare entity. Internal biliary fistulae are either spontaneous or due to operations on biliary tract. The common causes for spontaneous internal biliary fistula includes cholelithiasis, peptic ulceration and malignant neoplasm (Shiu) 1967. In a study of 819 cases by Waggoner and Le Mone (1949) 51% of such fistulae were cholecystoduodenal, 21% cholecystocolic, 19% choledocoduodenal, while the rest were choledocogastric and cholecystocholedocal. Most common cause for spontaneous choledocoduodenal fistula is due to gall stones, but, rarely posterior penetrating duodenal ulcer may also cause this condition. The following report concerns a spontaneous biliary fistula of the choledocoduodenal type, due to chronic duodenal ulcer.

Biliary Fistula↗