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Biomedical subjects

D W Carlson

Publications and source records attributed to D W Carlson.

14 recordsLinked to original sources
PubMed1997

A randomized study of mitomycin augmentation in combined phacoemulsification and trabeculectomy.

PURPOSE: The purpose of the study is to determine whether the intraoperative application of subconjunctival mitomycin C (MMC), during combined phacoemulsification and trabeculectomy, is an effective means of improving filtration, defined as overall lower intraocular pressure (IOP) and less antiglaucoma medication use. METHODS: Twenty-nine patients with a visually significant cataract and glaucoma were randomized, in a double-masked fashion, to receive intraoperative MMC (0.5 mg/ml) or placebo. RESULTS: Follow-up ranged from 6 to 30 months (mean, 20 months). Postoperative visual acuity at 1 year was 20/40 or better in 14 of 15 eyes operated on in the placebo group and 13 of 14 eyes operated on in the MMC group. Intraocular pressure at 8 months averaged 15.2 +/- 1.5 mmHg in the placebo-treated eyes versus 12.3 +/- 1.6 mmHg in the MMC-treated eyes. At 12 months, IOPs averaged 16.2 +/- 1.5 mmHg in the placebo-treated eyes versus 12.6 +/- 1.0 mmHg in the MMC-treated eyes. On average, the MMC group had postoperative IOP levels 3.0 mmHg lower than did the placebo group (P = 0.04) throughout the study. In the placebo group, laser suture lysis was required in a greater number of patients (80% versus 43%) and to a greater extent (mean = 2.0 versus 0.7 suture lysed) (P < 0.05). At 12 months, 5 of the 15 patients in the placebo group required an average of 1.8 medications for IOP control, whereas 0 of the 14 patients in the MMC group needed IOP-lowering medications. A late endophthalmitis developed through an intact bleb in one patient in the MMC group; otherwise, complications were minimal in each group. CONCLUSION: These results suggest that intraoperative MMC application, during combined phacoemulsification and trabeculectomy surgery, does improve early filtration as shown by overall lower IOPs and less antiglaucoma medication use.

Aged↗
PubMed1996

Laser synechialysis to prevent membrane recurrence on silicone intraocular lenses.

PURPOSE: To determine whether laser posterior synechialysis will prevent recurrence of pigmented membranes that can form on the anterior surface of silicone intraocular lenses. METHODS: Three patients (four eyes) had posterior synechiae and silicone intraocular lens surface membranes that required long-term corticosteroid treatment. Posterior synechiae were lysed by an Nd:YAG laser (1 to 2 mJ per burst; 148 to 485 applications; total energy, 296 to 896 mJ). RESULTS: All four eyes remained free of recurrence from 12 to 14 months. CONCLUSIONS: Silicone intraocular lens surface membranes emanated from posterior synechiae. The Nd:YAG laser synechialysis prevented recurrence and allowed discontinuation of corticosteroids.

Cell Membrane↗
PubMed1995

Aggressive nevus of the iris with secondary glaucoma in a child.

PURPOSE/METHODS: We studied a case of an aggressive iris nevus that caused secondary glaucoma in a child. RESULTS/CONCLUSION: Unlike most iris tumors, this tumor grew from the superior aspect of the iris. The nevus was also unusual because it invaded the trabecular meshwork and caused secondary glaucoma.

Adolescent↗
PubMed1995

Reduced vision secondary to pigmented cellular membranes on silicone intraocular lenses.

PURPOSE: Visually significant, pigmented cellular membranes may form on intraocular lenses after implantation. We studied a series of patients to determine the onset, visual significance, treatment, and recurrent nature of these pigmented membranes in patients who underwent surgery with silicone lens implantation. METHODS: In nine eyes (eight patients) with visually significant pigmented cellular membranes on their Allergan Medical Optics (Irvine, California) silicone intraocular lenses (model SI18NGB or SI26NB), eight underwent combined phacoemulsification, intraocular lens implantation, and trabeculectomy; one underwent phacoemulsification and lens implantation only. We reviewed medical records to identify preoperative, operative, and postoperative similarities and differences in care. Clinical examinations and slit-lamp photographs, over an average of 21.3 +/- 7.2 months (range, 11 to 31 months), documented the effects of different treatment modalities. RESULTS: The patients sought treatment ten to 20 weeks (mean, 15 weeks) postoperatively. Except for the cellular membranes, each eye was without evidence of inflammation or cystoid macular edema. Subjective complaints decreased, and best-corrected Snellen visual acuity improved with topical corticosteroid therapy alone. Pretreatment best-corrected visual acuities ranged from 20/40 to 20/400 (mean, 20/70 using Snellen fractions) and improved two to eight (mean, five) Snellen lines, to a range of 20/20 to 20/50 (mean, 20/25). All nine eyes had recurrence of the membranes after treatment terminated and required a maintenance regimen of corticosteroid eyedrops. CONCLUSION: The pigmented cellular membranes observed on these silicone lenses were visually significant to each patient. The membranes resolved and visual acuity improved with topical corticosteroid treatment alone but recurred in all patients on cessation of treatment.

Aged↗
PubMed1995

Updates in pediatric emergency medicine for the office practitioner.

Emergently ill or injured children may access care through their primary care provider, through prehospital emergency medical services, or directly in a hospital emergency unit. Primary health care providers and emergency care providers need to have the skills, proper equipment, and medications available to care for these children. This paper reviews recent articles on the prevention, evaluation, treatment, and outcomes of illness and injury in children, which should be of interest to primary and emergency care givers. Areas of recent research include the epidemiology, prevention, and evaluation of childhood injuries and the evaluation of infants and children with fever. Other areas reviewed are respiratory disease and the treatment of gastroenteritis. Also reviewed are articles on the role of the primary care physician in emergency medical services for children.

Child↗
PubMed1991

The career impact of keratoconus on Air Force aviators.

Keratoconus causes progressive blurring and distortion of vision, which threatens the career of a military aviator. To assess the impact of keratoconus on flying careers, we reviewed the records of all aviators with keratoconus who have been examined at the United States Air Force School of Aerospace Medicine over the past 23 years. Of the 22 aviators observed for more than three years, 18 were still qualified to fly at their most recent examination. The remaining four aviators were permanently removed from flying duties because of visual dysfunction caused by keratoconus. Of the 22 aviators examined, 15 required hard contact lenses for optimal correction of vision. No aircraft accidents or incidents, attributable to visual factors, were documented. We concluded that the majority of aviators with keratoconus are able to continue their flying careers safely with the aid of spectacles or contact lenses.

Adult↗
PubMed1991

Effect of succinylcholine on the intraocular contents of open globes.

The use of succinylcholine in patients with suspected or proven open globes is considered dangerous by some for fear of extruding the intra-ocular contents as a consequence of the co-contraction of the extraocular muscles it produces. To test this hypothesis, the authors devised an anterior and a posterior trauma model in the cat eye. Thirty events were studied using the anterior trauma model and eight with the posterior model. The only observable effect of succinylcholine administration was forward displacement of the lens and iris. No intraocular content was lost in any event. The authors believe this study supports the argument that, when indicated, succinylcholine may be considered in open globes.

Animals↗
PubMed1989

Touching the cornea enhances pharmacologic dilation of the pupil, mainly in the dark iris.

Adequate pupillary dilation is often difficult to achieve in darkly pigmented persons when using standard dilating drops. To quantify the degree to which mild corneal disruption could enhance this dilation, we touched the cornea of one eye and then placed dilating drops in both eyes of darkly pigmented and lightly pigmented subjects. The touch was either standard Gold-mann applanation tonometry or corneal reflex testing using a cotton-tipped applicator. Pupil diameter was measured using a video infrared pupillometer. The mean difference in pupil diameter between the touched and the control eye at 30 min was six-fold greater in darkly pigmented, compared to lightly pigmented, subjects. Touching the cornea by the method described herein appears to be a safe, useful technique for routinely enhancing pharmacologic dilation of the pupil in persons who have dark irises.

Adult↗
PubMed1988

Central serous chorioretinopathy in U.S. Air Force aviators: a review.

Idiopathic central serous chorioretinopathy (ICSC) is an uncommon disease with the potential to cause loss of visual acuity, decreased color vision, and decreased depth perception. These visual changes may become permanent and require removal of aviators from flight status. This study reviews 55 eyes of 47 USAF aviators with ICSC examined at the United States Air Force School of Aerospace Medicine (USAFSAM), Brooks AFB, TX. Clinical and aeromedical findings, both on initial and on follow-up ophthalmic examination were studied. Ninety-seven percent of aviators otherwise medically qualified were ultimately returned to flight status. Overall, 51% had recurrent episodes, 17% had bilateral disease, and 13% underwent laser photocoagulation. Visual acuity correlated with active disease, and there was a trend toward poor stereopsis and diminished color vision with worsening visual acuity. Eighty-six percent attained a final visual acuity of 20/20 or better. On final examination, 90% had normal stereopsis, 87% had normal color vision, and 49% had a normal central visual field. Eyes with recurrent disease tended to have degraded final visual acuity, stereopsis, color vision, and central visual field. The visual and aeromedical prognosis from a single attack of ICSC is generally favorable, but repeated attacks can lead to a significant decrease in visual functions that may jeopardize flying status.

Adult↗
PubMed1987

Role of sympathetic nerves during developing cardiac hypertrophy in Grollman hypertensive rats.

Peak left ventricular (LV) function, during rapid volume expansion, and cardiocyte structure were studied in rats with developing cardiac hypertrophy in response to Grollman hypertension (1 kidney, 1 figure 8) after chemical sympathectomy with 6-hydroxydopamine. This form of renovascular hypertension led to the same magnitude of hypertrophy in rats with or without sympathectomy. Indices of peak LV function, measured during acute volume expansion, tended to be normal or slightly higher in hypertensive rats than in controls. Sympathectomy in rats with hypertension significantly improved cardiac and stroke indices while decreasing total peripheral resistance at peak cardiac output. Despite similar magnitudes of LV hypertrophy (LVH) in the two hypertensive groups, cardiocytes in sympathectomized rats had higher mitochondrial volume densities and slightly lower myofibrillar volume densities. After regional sympathectomy of the anterior portion of the LV with phenol, mitochondrial volume density increased by 21% in hypertensive rats with LVH. These data indicate that, during the development of LVH in response to renovascular hypertension, sympathetic nerves do not contribute to the magnitude of LVH but may limit improvement in peak LV performance in response to increased preload. However, sympathetic nerves do play a role in the regulation of mitochondrial and myofibril growth.

Animals↗
PubMedDate not supplied

Femur fractures in chest-injured patients: is reaming contraindicated?

OBJECTIVE: To determine if reamed femoral intramedullary nailing increases the pulmonary complications seen in chest-injured patients. DESIGN: Retrospective review of prospectively collected trauma database data from January 1991 to October 1994. SETTING: Methodist Hospital, Indianapolis, Indiana, Level I Trauma Center. PATIENTS: Group I: Chest-injured patients [chest Abbreviated Injury Score (AIS) > or = 2] without femur or tibia fractures. Group II: Chest-injured patients (chest AIS > or = 2) with femoral reamed intramedullary fixation. Group III: Chest-injured patients (chest AIS > or = 2) with femoral shaft fixation using nonreamed fixation (rush rods, plating, or external fixation). Group IV: Non-chest-injured patients (chest AIS < 2) with femoral reamed intramedullary fixation. MAIN OUTCOME MEASUREMENT/HYPOTHESIS: Reamed femoral intramedullary nailing does not alter pulmonary outcomes, even in chest-injured patients. RESULTS: Groups I and II had a very similar incidence of adult respiratory distress syndrome (ARDS), pneumonia, and number of ventilator days. Group III had a significantly higher incidence of ARDS and number of ventilator days than did Group I or II. Group III did not have a chest AIS score significantly different than Groups I and II. Group II had significantly higher ARDS and more ventilator days than did Group IV when only analyzing raw data. When injury severity was adjusted, there were no significant differences in pulmonary outcomes. CONCLUSION: Reamed intramedullary femoral fixation did not increase pulmonary morbidity in chest-injured patients.

Adult↗