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Biomedical subjects

A B Thach

Publications and source records attributed to A B Thach.

At least 19 recordsLinked to original sources
PubMed2000

Eye injuries in a terrorist bombing: Dhahran, Saudi Arabia, June 25, 1996.

OBJECTIVE: We report the experience of our institution in the evaluation and care of multiple simultaneous ocular trauma patients after a terrorist bomb attack on a United States military base in Saudi Arabia. DESIGN: Retrospective, noncomparative small case series. PARTICIPANTS: Three patients who received severe ocular injuries after a terrorist bombing. INTERVENTION: All patients underwent surgical repair of the injuries that were inflicted as a result of the terrorist bombing. MAIN OUTCOME MEASURES: Baseline ocular characteristics, intraoperative findings, surgical procedures, and final (3 years after injury) anatomic and visual outcomes were noted. RESULTS: Glass fragments caused by the blast were the mechanism of all the ocular injuries in these patients. All patients had primary repair of the injuries done in Saudi Arabia and were sent to our institution for tertiary care. Three of the four eyes injured had stable or improved visual acuity and one eye was enucleated. Two patients had no serious injury other than the globe trauma. One patient had extensive eyelid trauma and required serial procedures to allow fitting of a prosthesis. CONCLUSIONS: Blast-injury patients are at risk for open globe injury as a result of glass fragments. The types of injury that can occur from terrorist blasts can be extensive and involve all the tissues of the eye, the ocular adnexa, and the orbit.

Adult↗
PubMed2000

Outcome of sulcus fixation of dislocated posterior chamber intraocular lenses using temporary externalization of the haptics.

OBJECTIVE: This study evaluated the visual outcome and complications of repositioning and sulcus fixation of a dislocated posterior chamber intraocular lens (PC IOL) using a technique in which the haptics of the IOL are temporarily externalized for suture placement. DESIGN: Retrospective, noncomparative case series. PARTICIPANTS: Seventy-eight patients with a dislocated PC IOL. INTERVENTION: All patients underwent surgery to fixate the PC IOL using this technique. MAIN OUTCOME MEASURES: Patients were evaluated for visual acuity, refractive error, and surgical complications associated with the procedure. RESULTS: The average visual acuity before surgery was 20/205 (range, 20/20 to light perception), with a median refractive error of -1.00 diopters (D; range, -7.25-+15.00 D). After surgery, the average visual acuity improved to 20/72 (range, 20/20 to no light perception), with a median refractive error of -0.75 D (range, -5.50-+3.50 D). Patients were observed for a median of 15.5 months (range, 6-57 months). Twenty patients had postoperative cystoid macular edema (26%), 7 patients had an epiretinal membrane (ERM) (9%), and 5 patients had a retinal detachment (6%). Eight patients (10%) experienced iris capture of the sutured IOL, and in three patients (4%) the PC IOL dislocated again after surgery. CONCLUSIONS: This technique is an effective method for securing a dislocated PC IOL.

Adult↗
PubMed2000

Eye injuries in the U.S. Armed Forces.

OBJECTIVE: To develop prevention and treatment modalities for eye injuries, ophthalmologists require epidemiological data on the various types of eye injuries. This study sought to define eye injury patterns in the U.S. armed forces. METHOD: Data on patterns of eye injury in the armed forces were obtained through voluntary reporting by U.S. military ophthalmologists throughout the world. The reporting format was standardized with the U.S. Eye Injury Registry initial and follow-up report forms. The data were analyzed for significant injury patterns. RESULTS: Data on 112 patients were submitted, representing a broad range of the military population. Data on a total of 96 patients with a 6-month follow-up were analyzed in this study. Immediately after injury, 43% of the patients were noted to have poor vision (worse than 20/200). After treatment, only 20% were noted to have poor vision. Patients lost an average of 21.6 days of work after a severe eye injury. CONCLUSION: An eye injury is a traumatic and potentially debilitating event. The loss of visual acuity can be drastic, resulting in an extensive recovery period.

Absenteeism↗
PubMed1999

Ocular injuries from paintball pellets.

OBJECTIVE: To evaluate the ocular effects of blunt trauma due to injury from a paintball pellet. DESIGN: Noncomparative case series. PARTICIPANTS: Thirteen patients who suffered ocular injury from paintballs are described. The patients presented to six different civilian and military emergency departments in tertiary care medical centers. INTERVENTION: Patients were treated for the ocular injury. MAIN OUTCOME MEASURES: Patients were evaluated for initial and final visual acuity. The reason for persistent loss of vision was delineated. RESULTS: There were 12 males and 1 female with an average age of 21 years (range, 12-33 years). Eleven of the 13 had no ocular protection at the time of the ocular injury. On initial examination, nine patients had a hyphema, nine had a vitreous hemorrhage, six had a retinal tear or detachment, three had corneal or corneal-scleral ruptures, and one had traumatic optic neuropathy. The final visual acuity was 20/40 or better in two patients, 20/50 to 20/150 in three patients, and 20/200 or worse in eight patients. CONCLUSION: Injuries due to paintball pellets can result in severe ocular damage and significant loss of vision. Eyecare professionals should be aware of the risks of this sport and must strongly advise participants to wear adequate protection when involved in this activity.

Adolescent↗
PubMed1999

Laser injuries of the eye.

With the increasing use of lasers in the military and industry, a moderate number of significant retina injuries have occurred. These injuries have been due to lasers in the visible and near-infrared spectrum primarily, with a pulse duration in the nanosecond range. Use of lasers in the ophthalmic community has resulted also in structural damage to the cornea, lens, IOL, and retina. Because we have no proven treatment for most injuries to the retina, we must continue to strongly emphasize the use of wavelength-specific protective goggles to try to prevent future eye injuries.

Animals↗
PubMed1998

Open globe injuries in children.

PURPOSE: A retrospective review of open globe injuries in children was performed to identify the common types of injury and to correlate features of the injuries and surgical management with visual prognosis. METHODS: The hospital records of 70 patients were reviewed to determine demographic data, the nature and location of the injuries, the anatomic and functional status of the injured eye before the initial repair, the details of all primary and subsequent surgical procedures, and the final visual outcome. RESULTS: Fifty of the patients studied (71%) were male and 20 (29%) were female. The average age of the patients was 5 years. Sharp objects caused the majority of injuries (67%). Most of the injuries happened at home (72%). The cornea was involved in a majority of the injuries (92%). Thirty-two eyes (46%) required only primary repair; 15 eyes (21%) required primary repair with anterior vitrectomy and primary lensectomy; 17 eyes (24%) underwent secondary lensectomy or vitreoretinal surgeries, and 5 eyes (7%) were enucleated. Visual acuity of 20/40 or better was achieved by 45% of those patients who required only primary repair. Of those patients requiring a second procedure, 19% had a visual acuity of 20/40 or better. Initial clinical findings associated with an unfavorable visual outcome were retinal detachment, relative afferent pupillary defect, vitreous hemorrhage, and hyphema. CONCLUSION: The prognosis after an open globe injury in children is strongly influenced by the nature of the injury and the extent of the initial damage. Visual outcome is better in eyes that require only primary repair.

Adolescent↗
PubMed1998

Retinopathy of prematurity: evaluation of risk factors.

OBJECTIVES: The purpose of this study was to determine what risk factors play a role in the development of retinopathy of prematurity (ROP). STUDY DESIGN: Data were collected on 157 infants born and cared for in one institution between January 1991 and July 1994. Initially we evaluated all children enrolled in the study to determine potential risk factors for the development of ROP. We subsequently compared multiple variables for ROP positive singletons with ROP positive twins to determine ROP risk factors for each group and to determine if one group was more susceptible to a given risk factor. RESULTS: Of the 157 infants examined, 72 infants (46%) developed ROP. Infants who developed ROP had a lower gestational age, a lower birth weight, a higher number of days on oxygen/ventilator, more days in the intensive care unit (ICU), a greater need for steroids and a higher incidence of sepsis when compared to infants who did not develop ROP. There was no significant difference noted between singleton and twin gestation infants that developed ROP when comparing gestational age, weight, ventilator time or length of ICU stay. Total number of days on oxygen therapy was higher in the singleton group and this difference did reach statistical significance. CONCLUSIONS: Several risk factors are associated with a higher incidence of ROP. These variables may not be independent risk factors but may be a sign of the increased severity of illness associated with those infants who are born earlier with a lower birth weight. Multiple gestational births do not appear to increase the risk of developing ROP when compared to a similar group of singleton birth infants.

Female↗
PubMed1997

A comparison of retrobulbar versus sub-Tenon's corticosteroid therapy for cystoid macular edema refractory to topical medications.

OBJECTIVE: The objective is to compare the effectiveness of retrobulbar and posterior sub-Tenon's injection of corticosteroids for treatment of post-cataract cystoid macular edema that was refractory to topical medications. DESIGN: A retrospective study was performed. PARTICIPANTS: A total of 48 patients (49 eyes) with post-cataract cystoid macular edema refractory to topical medications was studied. INTERVENTION: Patients received either a single retrobulbar injection (18 eyes) or 3 biweekly posterior sub-Tenon's injections (31 eyes) of corticosteroids. MAIN OUTCOME MEASURES: Patients were observed for clinical resolution of the cystoid macular edema, visual acuity, and intraocular pressure. RESULTS: Both treatment methods resulted in significant improvement in visual acuity. The posterior sub-Tenon's group had a visual improvement from 20/92 pretreatment to 20/50 post-treatment (P = 0.0001) with a median follow-up of 12 months. The retrobulbar group had a visual improvement from 20/97 pretreatment to 20/58 post-treatment (P = 0.035) with a median follow-up of 10 months. The visual improvement was not significantly different between the two groups. The average intraocular pressure increased from a pretreatment level of 14.1 mmHg to a high of 17.7 mmHg (P < 0.00005) in the sub-Tenon's group. The average intraocular pressure increased from 15.1 mmHg to a high of 17.6 mmHg (P = 0.04) in the retrobulbar group. CONCLUSIONS: Cystoid macular edema that persists after treatment with topical medications may improve after retrobulbar or posterior sub-Tenon's corticosteroid injections. There was no significant difference in outcome between the two treatment groups.

Administration, Topical↗
PubMed1997

Annular peripheral choroidal detachment simulating aqueous misdirection after glaucoma surgery.

PURPOSE: The purpose of the study was to define a newly recognized complication after glaucoma surgery and to recommend a therapeutic regimen. METHODS: Eighteen patients diagnosed initially as having aqueous misdirection after glaucoma surgery, but who subsequently were found by ultrasonography to have an annular peripheral choroidal detachment that resulted in secondary angle closure glaucoma, were studied. Ten of these patients were treated with topical cycloplegics and corticosteroids, and 8 were treated with drainage of suprachoroidal fluid. Outcomes of these two treatment methods were compared. RESULTS: Annular peripheral choroidal detachment reliably was diagnosed with ultrasonography. Of the variables studied, time elapsed before resolution of the annular peripheral choroidal detachment was noted to be statistically significant (P < 0.00005). Immediate resolution followed drainage of suprachoroidal fluid, whereas a mean of 19.6 days was required for resolution after medical therapy. CONCLUSIONS: Annular peripheral choroidal detachment should be considered in the differential diagnosis of a flat or shallow anterior chamber with normal or high intraocular pressure after glaucoma surgery. The diagnosis of annular peripheral choroidal detachment can be confirmed most reliably by ultrasonography. Medical therapy is as effective as is surgery, although a significantly longer time to resolution is required.

Adult↗
PubMed1997

Presumed multifocal cryptococcol choroidopathy prior to specific systemic manifestation.

PURPOSE: Disseminated cryptococcosis is a major cause of morbidity and mortality in immunocompromised individuals, especially those with the acquired immunodeficiency syndrome (AIDS). Early diagnosis and treatment greatly improves the outcome, so clinical clues that lead to prompt diagnosis are important. METHODS: Three patients with AIDS in whom multifocal choroiditis and choroidal lesions were the initial signs of disseminated cryptococcosis were treated with systemic amphotericin B and flucytosine. All of the patients had a systemic work-up that included evaluation of the cerebral spinal fluid (CSF). RESULTS: All three patients who were seen with the choroidal lesions as the presenting sign were noted to have either positive titers for cryptococcus or cultures that grew cryptococcus in the CSF. The choroidal lesions are presumed to be due to cryptococcus as no histopathologic or microscopic studies were available for ocular tissues. The choroidal lesions started to resolve one to three months after systemic treatment with amphotericin B and flucytosine. CONCLUSION: Primary choroidal lesions in patients with AIDS may herald severe systemic disseminated disease. Funduscopic examination, however, may detect disseminated cryptococcal disease before other overt clinical manifestations, thereby allowing prompt institution of effective therapy.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Retinal manifestations of acute murine typhus.

PURPOSE: To report the ocular manifestations of acute serologically confirmed murine typhus. METHODS: A retrospective analysis of the clinical history, photography and fluorescein angiography of two patients with acute murine typhus with ocular involvement was conducted. RESULTS: A 38 year old male and a 49 year old female were included in the study. Both complained of fever, headache, rash, night sweats and pulmonary symptoms. They had noted the recent onset of diminished visual acuity and floaters. Examination of the posterior pole revealed mild optic nerve head edema (in one patient), intraretinal hemorrhages and small localized areas of retinal whitening. The history confirmed that both patients had been exposed to fleas and the serologic testing was positive for Rickettsia typhi. The systemic and ocular findings resolved after the use of systemic antibiotics. CONCLUSION: Rickettsial diseases such as murine typhus should be included in the differential diagnosis of otherwise healthy individuals who present with an acute systemic febrile illness and retinitis or neuroretinitis. SUMMARY STATEMENT: The clinical features of two patients with serologically proven acute murine typhus with ocular involvement are presented. Both patients presented with a retinal whitening that resolved after treatment.

Acute Disease↗
PubMed1996

Cytomegalovirus papillitis in patients with acquired immune deficiency syndrome. Visual prognosis of patients treated with ganciclovir and/or foscarnet.

BACKGROUND: Of those patients with acquired immune deficiency syndrome in whom cytomegaloviral retinitis develops, cytomegaloviral papillitis reportedly develops in up to 4% as well. Although occasionally patients have a good visual outcome, the majority have a poor visual prognosis, with a visual acuity of 20/200 or worse, even with treatment. METHODS: To evaluate the effects of prolonged induction with foscarnet or ganciclovir on the visual prognosis of cytomegalovirus (CMV) papillitis, the records of 22 patients seen between 1990 and 1995 at the Los Angeles County-University of Southern California Eye Clinic were reviewed. Papillitis was defined as greater than 270 degrees of disc edema/blurring of the disc margins as seen on direct examination and on color fundus photographs. RESULTS: Eighteen patients with a mean initial visual acuity of 20/69 (range, 20/ 15-20/400) were treated with induction doses of intravenous ganciclovir (range, 5-7.5 mg/kg twice daily) or foscarnet (range, 60-90 mg/kg twice or 3 times daily) for a mean of 3.3 weeks. The mean follow-up period was 4.8 months (range, 1-13 months). These patients maintained a mean final visual acuity of 20/68 (range, 20/ 25-20/400) with greater than 90% resolution of the papillitis. The remaining four patients had poor outcomes (visual acuity < 20/400) because of progressive CMV papillitis or retinitis. The median survival time was 4.5 months from the diagnosis of papillitis, but 7 months from the onset of CMV ocular infection. CONCLUSION: Patients with CMV papillitis have good visual prognosis when managed with high and prolonged doses of intravenous foscarnet and/or ganciclovir.

AIDS-Related Opportunistic Infections↗
PubMed1996

The effects of California Proposition 187 on ophthalmology clinic utilization at an inner-city urban hospital.

PURPOSE: To determine the effect on ophthalmology clinic utilization at a major public inner-city hospital of California Proposition 187 and the debate surrounding its passage. Proposition 187 was a statewide referendum passed by 63% of the electorate in the November 1994 election that would restrict social services to undocumented immigrants and require providers to report them to immigration authorities. METHODS: The ophthalmology clinic volume at the Los Angeles County/ University of Southern California Medical Center was analyzed from October 1 to December 31, 1993 and 1994. RESULTS: New walk-in patients significantly decreased (P < 0.001) for a 2-month period around the election, but returned to baseline levels in December 1994. The new patient cancellation and no show rate was not affected. No change in return patient behavior was noted for general and specialty clinics. CONCLUSIONS: Proposition 187 may have caused a statistically significant decrease in new walk-ins to the ophthalmology clinics during a 2-month period surround the November 1994 election, but it had no measurable effect on other indicators of utilization. In addition, utilization rates returned to baseline after the implementation of Proposition 187 was stayed by the judicial system, and concern that providers would be required to report undocumented immigrants to authorities was alleviated.

Appointments and Schedules↗
PubMed1996

Transdifferentiated retinal pigment epithelial cells are immunoreactive for vascular endothelial growth factor in surgically excised age-related macular degeneration-related choroidal neovascular membranes.

PURPOSE: To determine the cellular origin and the vascular endothelial growth factor (VEGF) immunoreactivity of the nonvascular stromal cells in surgically excised age-related macular degeneration (ARMD)-associated choroidal neovascular membranes (CNVMs). METHODS: Immunohistochemical analysis was performed on frozen sections of eight surgically excised ARMD-related CNVMs. RESULTS: Cytokeratin-positive, smooth muscle actin-positive polygonal or fibroblastic (transdifferentiated RPE) cells were the principal nonvascular stromal cells detected. The polygonal cells were more commonly found in active (highly vascularized) regions and were strongly immunoreactive for VEGF. The fibroblastic cells were predominantly found in fibrotic (hypovascular) regions and were minimally immunoreactive for VEGF. CONCLUSIONS: Transdifferentiated RPE cells are the principal nonvascular stromal cells of both vascular and fibrotic ARMD-related CNVMs. Preferential localization of VEGF immunoreactivity with the cytoplasm of the polygonal transdifferentiated RPE cells in the highly vascularized regions of the surgically excised CNVMs suggests an important angiogenic role of these cells and this growth factor in the progression of ARMD-related choroidal neovascularization.

Actins↗
PubMed1995

Accidental Nd:YAG laser injuries to the macula.

PURPOSE: To study the clinical course of accidental, single-focus Nd:YAG laser injuries to the macula. METHODS: We reviewed the clinical course of five eyes (four patients) that sustained macular injuries from a Nd:YAG laser. All patients were examined within 24 hours of injury and were observed without surgical intervention for a mean of 20 months (range, 12 to 32 months). RESULTS: A single full-thickness foveal or parafoveal retinal hole was apparent in all eyes either on initial examination or within two weeks of injury. All macular holes were within 650 microns of the foveal center. The mean final visual acuity was 20/60 (range, 20/25 to 20/400) and was related to the distance between the macular hole and the foveal center. None of the eyes developed either subretinal neovascularization or clinically significant epiretinal membrane formation during the study period. CONCLUSIONS: Despite initial poor visual acuity in patients who had a full-thickness foveal or parafoveal retinal hole, visual acuity improved without treatment when the site of the laser injury was located outside the foveal center.

Adult↗
PubMed1994

En bloc capsulectomy in the diagnosis and treatment of refractory, chronic, recurrent pseudophakic endophthalmitis.

Anterior chamber and vitreous aspiration may fail to isolate a microorganism in chronic pseudophakic endophthalmitis. In some eyes, obtaining a portion of the central posterior lens capsule may assist in determining the infectious etiology of the endophthalmitis. We describe a technique by which the entire lens capsule and its internal contents are removed and cultured. This surgical method facilitated the isolation and eradication of the causative pathogen in a patient with chronic recurrent pseudophakic endophthalmitis that was diagnostically and therapeutically refractory to previous vitrectomy, posterior capsulectomy, and intravitreal antibiotic injection.

Aged↗
PubMed1991

Phacoanaphylactic endophthalmitis: a clinicopathologic review.

Lens-induced uveitis or phacoanaphylactic endophthalmitis (PE) is a chronic endophthalmitis with a zonal granulomatous inflammation surrounding a ruptured lens. One hundred forty four cases of PE were retrospectively evaluated clinically and histopathologically. The disease was not well recognized clinically as only six of the cases were given the clinical diagnosis of PE. Most cases (80%) occurred after trauma, surgical or non-surgical. The time after injury varied from two days to fifty nine years. Of those individuals less than 55 years of age who had no history of trauma. 29% were noted by clinical history to have microphthalmia. Although classically the inflammation of PE has been described as being confined to the anterior aspect of the eye, the choroid was involved with an inflammatory reaction in 76% of the cases.

Acute Disease↗