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Biomedical subjects

G K Shah

Publications and source records attributed to G K Shah.

35 records · Page 2Linked to original sources
PubMed1999

Ultrasound biomicroscopy as a tool for detecting and localizing occult foreign bodies after ocular trauma.

OBJECTIVE: To show the utility of ultrasound biomicroscopy (UBM) in imaging small ocular foreign bodies of the anterior segment. DESIGN: Retrospective case series. PARTICIPANTS: Twelve eyes of 12 consecutive patients evaluated in the emergency department or referred to specialty services at 1 institution between August 1994 and November 1997 were examined. INTERVENTION: Ocular ultrasound biomicroscopy was performed. MAIN OUTCOME MEASURES: Detection and localization of an ocular foreign body were measured. RESULTS: An intraocular or superficial foreign body was detected by UBM in 9 (75%) of 12 eyes. The foreign body was classified as corneal in two eyes, subconjunctival in two, intrascleral in three, and intraocular in two eyes. The foreign body was not visible by ophthalmic physical examination in seven of the nine eyes with a confirmed ocular foreign body. In the remaining two eyes, UBM was used to determine the depth of a visible foreign body. In three of the eyes with a confirmed foreign body, computed tomography and/or contact B-scan ultrasonography was obtained and failed to show a foreign body. Six of the foreign bodies were nonmetallic. CONCLUSIONS: Clinical detection of ocular foreign bodies after trauma can be hindered by small size, haziness of the optical media, poor patient cooperation, or hidden location. Ultrasound biomicroscopy is a valuable adjunct in the evaluation of suspected ocular foreign bodies, especially in cases involving small, nonmetallic objects.

Adult↗
PubMed1999

Treatment strategies for postoperative Propionibacterium acnes endophthalmitis.

PURPOSE: Propionibacterium acnes endophthalmitis after cataract extraction and posterior chamber intraocular lens (IOL) implantation is characterized by a chronic indolent course, frequently associated with recurrence after standard endophthalmitis treatment. This study was designed to evaluate the efficacy of various therapeutic methods in the treatment of primary and recurrent episodes of postoperative P. acnes endophthalmitis. DESIGN: Retrospective, noncomparative case series. PARTICIPANTS: Twenty-five patients treated at Wills Eye Hospital for P. acnes endophthalmitis. METHODS: The authors retrospectively reviewed the clinical charts and microbiology files of all patients treated at Wills Eye Hospital between January 1991 and April 1998 with culture-proven P. acnes endophthalmitis after cataract extraction and posterior chamber IOL implantation. MAIN OUTCOME MEASURES: Results of cultures and microbiologic examinations, efficacy of various treatment methods in the prevention of recurrent inflammatory episodes, and final visual outcome. RESULTS: Twenty-five patients who met inclusion criteria were identified; initial therapy consisted of 1 of the following: intraocular antibiotic (IOAB) injections alone (2 patients); IOAB combined with pars plana vitrectomy (PPV) (10 patients); IOAB and PPV combined with partial capsulectomy (9 patients); and IOAB, PPV, total capsulectomy, and IOL exchange (4 patients). Nearly half of the patients (10 of 21, or 48%) initially treated with IOAB alone (1 of 2), IOAB and PPV (5 of 10), and IOAB combined with PPV and partial capsulectomy (4 of 9) required further therapeutic interventions for recurrent disease. Retreatment with IOAB alone or combined with PPV and partial capsulectomy in these patients failed to eradicate the infection in three (75%) of four patients. None of the patients (0 of 4) treated initially with total capsulectomy and IOL exchange required additional surgical intervention. Furthermore, none of the patients (0 of 13) who underwent total capsulectomy with IOL removal or exchange or IOL exchange alone as an initial, secondary, or tertiary treatment required further intervention. CONCLUSION: In the authors' series, approximately half of the patients with P. acnes endophthalmitis were treated successfully initially with nonsurgical or limited surgical intervention. All patients treated with total capsulectomy and IOL exchange or removal, either as an initial treatment or for recurrent disease, were cured. Removal of the entire capsular bag and the IOL may be performed as a definitive initial therapy and should be performed for recurrent inflammation.

Adult↗
PubMed1998

Branch retinal vein obstruction secondary to retinal arteriovenous communication.

PURPOSE: To document a branch retinal vein obstruction secondary to a congenital arteriovenous communication. METHOD: Case report of a young patient with retinal arteriovenous communication. RESULTS: A 12-year-old girl had a grade 2 retinal arteriovenous communication in her right eye. She was asymptomatic and was subsequently followed up. Magnetic resonance imaging of the brain was normal and disclosed no signs of Wyburn-Mason syndrome. Nine years later, she developed a branch retinal vein obstruction in the area of the arteriovenous communication. Six months later, the patient was free of secondary complications of branch retinal vein obstruction; however, she is being followed up to detect any retinal or iris neovascularization. CONCLUSION: Awareness of retinal vascular obstruction associated with arteriovenous communication may help its timely recognition, as well as prompt treatment of potential complications, such as retinal and iris neovascularization.

Arteriovenous Fistula↗
PubMed1998

Rhegmatogenous retinal detachments with cytomegalovirus retinitis.

The most important ocular opportunistic infection in patients with AIDS is cytomegalovirus (CMV) retinitis. Management of CMV retinitis has become complex, as the life expectancy of many patients has increased exponentially. Most retinal detachments in CMV retinitis are rhegmatogenous in nature. Because of atrophic changes in the retina and alterations in the vitreous, surgical management of these detachments leads to a stepladder approach. Options include laser demarcation, scleral buckle, and vitrectomy with silicone oil. In some patients, a combination of all three procedures may be necessary. Management in all cases should be individualized, with the realization that failure of retinal reattachment may occur.

AIDS-Related Opportunistic Infections↗
PubMed1998

The role of ultrasound biomicroscopy in ocular trauma.

PURPOSE: To demonstrate the usefulness of ultrasound biomicroscopy (UBM) in detecting and localizing small ocular foreign bodies. METHODS: This is a retrospective study of the records of 555 consecutive patients evaluated by UBM by the Visual Physiology Unit of the Wills Eye Hospital from August 1994 to November 1997. RESULTS: In 9 patients, a foreign body was identified. In 6 patients, the history suggested the presence of a foreign body, but one could not be detected by clinical examination. In 2 patients, the referring physicians requested UBM to determine whether or how deep a known foreign body had penetrated the globe. In 1 patient, the foreign body was not suspected clinically. In regard to other diagnostic techniques, CT failed to identify the foreign body in 1 patient. In another, contact B-scan ultrasonography failed. In a third, both CT and contact B-scan ultrasonography failed. The foreign body was intracorneal in 2 eyes, subconjunctival in 2, intrascleral in 3, and intraocular in 2. Six were nonmetallic. Two were metallic. In one case, the foreign body was lost and its composition is unknown. In 5 cases, the UBM findings altered the patient's management. CONCLUSIONS: UBM is a valuable adjunct in the evaluation of small, anteriorly located foreign body that may not be detectable by other methods. UBM may be especially useful for finding nonmetallic foreign bodies.

Adult↗
PubMed1997

Optic nerve neovascularization in incontinentia pigmenti.

PURPOSE: To describe the presence of optic disk neovascularization in a child with incontinentia pigmenti. METHODS: A 6-month-old infant with incontinentia pigmenti developed optic disk neovascularization in addition to vascular abnormalities in the peripheral retina. Panretinal photocoagulation was performed. RESULT: The optic disk neovascularization regressed after panretinal photocoagulation. CONCLUSIONS: Optic disk neovascularization is another notable retinal manifestation of incontinentia pigmenti. When optic disk neovascularization is detected, retinal ablation should be considered as treatment.

Female↗
PubMed1996

Diagnosis of microsporidial keratitis by confocal microscopy and the chromatrope stain.

PURPOSE: To illustrate the value of confocal microscopy and chromatrope stain in the diagnosis of microsporidial keratitis. METHODS: In vivo confocal microscopy was performed on a man with the human immunodeficiency virus who had severe bilateral epithelial keratitis refractory to topical antibacterial medications. The results were compared to conjunctival scrapings stained with the chromatrope-based Weber stain. RESULTS: Confocal microscopy demonstrated many small, intraepithelial opacities of the corneal epithelium, which were suggestive of Microsporidia. Results of the chromatrope stain of conjunctival scrapings confirmed the diagnosis of microsporidial keratitis. CONCLUSIONS: Rapid diagnosis allowed prompt initiation of topical fumagillin, which permitted rapid, long-term control of the symptoms of microsporidial keratitis.

AIDS-Related Opportunistic Infections↗
PubMed1995

Vortex keratopathy associated with atovaquone.

PURPOSE: We studied a case of vortex keratopathy that was associated with the use of atovaquone. METHOD: A patient with acquired immunodeficiency syndrome (AIDS) with pulmonary Pneumocystis carinii was treated with 750 mg of atovaquone three times a day. RESULTS: Similar to previous findings of drug-induced vortex keratopathy, atovaquone vortex keratopathy is presumably caused by its lipophilic properties. This property is similar to that of other lipophilic agents such as amiodarone, chloroquine, chlorpromazine, quinacrine, and suramin. CONCLUSION: Atovaquone should be added to the list of agents causing vortex keratopathy involving the corneal epithelium.

AIDS-Related Opportunistic Infections↗
PubMed1992

Ketamine suppresses ischemic injury in the rabbit retina.

Overstimulation of the N-methyl D-aspartate (NMDA) receptor has been implicated as a factor in the pathogenesis of ischemic injury in the central nervous system. The present study was undertaken to determine whether ketamine hydrochloride, a potent NMDA antagonist, could attenuate ischemic injury in the rabbit retina. Retinal ischemia was induced for 60 min in one eye of 18 albino rabbits by raising intraocular pressure above the systolic blood pressure. Three concentrations of ketamine, 0.5, 1.5, 5.0 mumol were dissolved in 20 microliters of saline solution and injected in the midvitreous in each eye of 14 rabbits 1 hr prior to ischemia. Four rabbits received saline solution as controls. The scotopic electroretinogram was monitored in each eye to assess the postischemic recovery of retinal function. A statistically significant reduction in the b-wave was detected in the eyes treated with saline (P less than 0.05), whereas the postischemic recovery of b-wave amplitude was enhanced by pretreatment with lower doses of ketamine. The highest dose depressed b-wave amplitude regardless of ischemia. Six rabbits underwent unilateral ocular ischemia under general anesthesia with ketamine. A small ameliorative effect was seen (P = 0.029). These results suggest that ketamine may alleviate ischemic injury in the rabbit retina, presumably by antagonizing the NMDA receptor-mediated toxicity. Thus, ketamine may have potential in the treatment of retinal vascular occlusive diseases. Moreover, a modified ischemic state may exist in experiments on ischemia conducted under general anesthesia with ketamine hydrochloride.

Animals↗
PubMed1979

Demonstration of bleeding site by 99mTc-labeled red cells.

Radionuclide angiography using in vivo 99mTc-tagged red cells demonstrated different bleeding sites in one patient on three occasions. The study is easy to perform and may be more sensitive than contrast angiography in the presence of slow bleeding.

Angiography↗
PubMedDate not supplied

Phacoemulsification and modern cataract surgery.

The techniques and results of cataract surgery have changed dramatically during the past three decades. In the USA, we have moved from intracapsular cataract extraction as the preferred technique to almost exclusively extracapsular techniques. Smaller incisions have become the standard, with phacoemulsification now being the method of choice for most surgeons. Along with these advances have come improved intraocular lens materials and designs, especially well suited for use with smaller incisions. Phacoemulsification as a method to remove the cataractous lens was first proposed more than 20 years ago. Advances in techniques and equipment have led to a dramatic increase in the popularity of phacoemulsification with increased safety and efficiency. Viscoelastic agents have been developed synchronously with modern phacoemulsification techniques, playing an integral role in the success of this new technology. Improved surgical techniques for removing the anterior lens capsule have decreased the incidence of both intraoperative and postoperative capsular complications. Nucleus removal, formerly performed primarily in the anterior chamber, is now performed in the posterior chamber, decreasing damage to the corneal endothelium. Improved wound construction allows many wounds to be left unsutured, and smaller wounds allow shorter recovery time and greater intraoperative control and safety. Intraocular lenses can have smaller optic sizes and still maintain accurate centration. Foldable intraocular lenses can take advantage of the smaller incision, even further shortening the time to visual recovery. Continual evolution of this technology promises to further improve patient outcomes after cataract surgery.

Anesthesia, Local↗
PubMedDate not supplied

Lipemia retinalis.

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Adult↗