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Biomedical subjects

L Benjamin

Publications and source records attributed to L Benjamin.

At least 19 recordsLinked to original sources
PubMed2005

Iatrogenic eccentric full thickness macular holes following vitrectomy with ILM peeling for idiopathic macular holes.

PURPOSE: To document a previously unreported complication after vitrectomy with peeling of the internal limiting membrane (ILM) for idiopathic macular holes. METHOD: Retrospective review of notes of 232 consecutive patients who underwent vitrectomy with peeling of the ILM for idiopathic macular holes from 1996 to 2001. Four patients were found to have eccentric iatrogenic macular holes postoperatively. Optical coherence tomography was used to evaluate these holes. RESULTS: The idiopathic macular holes were graded from stages II to IV preoperatively with visual acuities from 6/18 to 6/60. All patients had surgery within 6 months of presentation. They underwent vitrectomy with complete separation of the posterior cortical vitreous, peeling of the ILM, injection of platelets (0.1 ml), and gas tamponade with SF6 20%. Postoperatively the patients postured strictly face down for 10 days. Follow-up ranged from 8 months to 6 years. Iatrogenic eccentric macular holes were noted postoperatively. The holes were located between 3 and 6 o'clock in three patients and at 9 o'clock in the fourth patient, relative to the macula. Optical coherence tomography showed them to be full thickness and completely flat. No further intervention was necessary. No complications have arisen during follow-up. COMMENT: To our knowledge iatrogenic eccentric full thickness macular holes after macular hole surgery have never been reported. We believe that the location of the holes represents the initial site of ILM elevation. These holes are asymptomatic, have not required any treatment and have not caused any complications in up to 6 years of follow-up.

Aged↗
PubMed2002

Dilated pupils and loss of accommodation following diode panretinal photocoagulation with sub-tenon local anaesthetic in four cases.

AIM: To describe pupillary abnormalities associated with diode laser photocoagulation with subTenon's local anaesthetic. METHODS: We describe four cases of tonic pupils following diabetic panretinal photocoagulation with subTenon's local anaesthetic. RESULTS: Six pupils of four patients became dilated and sustained loss of accommodation with denervation hypersensitivity with 0.1% pilocarpine after undergoing panretinal photocoagulation with a subTenon's local anaesthetic. The numbers of burns were not excessive and in one patient it even occurred after only 1200 laser burns. CONCLUSION: Diode laser causes histological changes deeper in the retina and the choroid than in Argon laser. Intense diode laser burns may cause damage to the short ciliary nerves traversing the choroid. In the unanaesthetised patient, pain arises when the laser burn hits these nerves and so may protect the eye from excess damage to the nerves. When the eye is anaesthetised with a subTenon's, local anaesthetic damage to the choroidal nerves may occur without the laser operator being aware that the burns are too intense.

Adult↗
PubMed2002

Nd:YAG vitreolysis and pars plana vitrectomy: surgical treatment for vitreous floaters.

PURPOSE OF STUDY: To determine the efficacy of Nd:YAG vitreolysis and pars plana vitrectomy in the treatment of vitreous floaters. METHODS: This is a single centre retrospective study of 31 patients (42 eyes) who underwent 54 procedures, Nd:YAG vitreolysis or pars plana vitrectomy, for the treatment of vitreous floaters between January 1992 and December 2000. Main outcome measures were percentage symptomatic improvement following treatment and incidence of post-operative complications. Statistical analysis was performed using the Fisher exact test. RESULTS: Posterior vitreous detachment was the primary cause of floaters in all 42 eyes with co-existing vitreous veils in three eyes and asteroid hyalosis in two eyes. Thirty-nine of 42 eyes received Nd:YAG vitreolysis. Thirty-eight percent found Nd:YAG vitreolysis moderately improved their symptoms while 61.5% found no improvement. After an average of 14.7 months follow-up no post-operative complications were recorded. Fifteen eyes underwent a pars plana vitrectomy, one with combined phacoemulsification and posterior chamber implantation and 11 following unsuccessful laser vitreolysis. Pars plana vitrectomy resulted in full resolution of symptoms in 93.3% of eyes. One patient developed a post-operative retinal detachment which was successfully treated leaving the patient with 6/5 VA. CONCLUSION: Patients' symptoms from vitreous floaters are often underestimated resulting in no intervention. This paper shows Nd:YAG vitreolysis to be a safe but only moderately effective primary treatment conferring clinical benefit in one third of patients. Pars plana vitrectomy, while offering superior results, should be reserved for patients who remain markedly symptomatic following vitreolysis, until future studies further clarify its role in the treatment of patients with floaters and posterior vitreous detachment.

Adult↗
PubMed2000

The impact of amphetamine-related disorders on community psychiatric emergency services: 1993-1997.

Trends in number, relative prevalence, and demographics of adult psychiatric admissions to the county psychiatric emergency service in Sacramento, California, for treatment of Amphetamine-Related Disorders (ARDs) (N = 2,428) between July 1993 and July 1997 were examined. ARDs accounted for 11.2% of all emergency admissions (N = 21,615) and were the most frequent substance-related disorder requiring admission during the study period. Patients with ARDs tended to be Caucasian or Hispanic males in their mid 30s. 38% of the ARD patients required further inpatient psychiatric care. The trends in numbers of ARDs tended to parallel other local and national non-psychiatric indicators of amphetamine-induced morbidity.

Adolescent↗
PubMed1999

Measuring the effectiveness of cataract surgery: the reliability and validity of a visual function outcomes instrument.

AIMS: To assess test-retest reliability and validity of the "TyPE" patient self assessed visual function questionnaire, as part of a study in two hospitals measuring the effectiveness of cataract surgery. The American TyPE questionnaire had minor adaptations made for use in Britain. METHODS: Test-retest reliability was assessed on 63 out of 378 adult cataract surgery patients in the study, using Spearman correlation coefficients and kappa coefficients of agreement. "Construct" validity was evaluated by comparing the association between changes in visual function questionnaire scores after surgery, with patients' perception of change in visual function obtained by independent interview of 24 patients. RESULTS: The TyPE questionnaire items showed very good test-retest reliability. Average Spearman and kappa coefficients for 39 patients from hospital 1 were 0.93 and 0.84 respectively. Spearman and kappa coefficients of 0.9 and 0.81 were obtained for those nine patients in hospital 2 where both the test and retest questionnaires were filled in by the same people. However, for the 15 patients from hospital 2, where the questionnaire was filled in by different people in the retest, reliability was less good: the Spearman coefficients were still high, average 0.72, but the kappa coefficients were poor, 0.27. Good construct validity was exhibited, with a correlation of 0.79 between change in distance vision score from the questionnaires and the independent interview. CONCLUSIONS: The adapted TyPE questionnaire is both very reliable and has good construct validity. The kappa coefficient should be used wherever possible to evaluate reliability. The test-retest reliability and validity and practicability of other visual function questionnaires have not been assessed adequately, and further development should be carried out of all such questionnaires, so that they may be introduced into routine clinical care.

Activities of Daily Living↗
PubMed1998

Endothelial cell death, angiogenesis, and microvascular function after castration in an androgen-dependent tumor: role of vascular endothelial growth factor.

The sequence of events that leads to tumor vessel regression and the functional characteristics of these vessels during hormone-ablation therapy are not known. This is because of the lack of an appropriate animal model and monitoring technology. By using in vivo microscopy and in situ molecular analysis of the androgen-dependent Shionogi carcinoma grown in severe combined immunodeficient mice, we show that castration of these mice leads to tumor regression and a concomitant decrease in vascular endothelial growth factor (VEGF) expression. Androgen withdrawal is known to induce apoptosis in Shionogi tumor cells. Surprisingly, tumor endothelial cells begin to undergo apoptosis before neoplastic cells, and rarefaction of tumor vessels precedes the decrease in tumor size. The regressing vessels begin to exhibit normal phenotype, i.e., lower diameter, tortuosity, vascular permeability, and leukocyte adhesion. Two weeks after castration, a second wave of angiogenesis and tumor growth begins with a concomitant increase in VEGF expression. Because human tumors often relapse following hormone-ablation therapy, our data suggest that these patients may benefit from combined anti-VEGF therapy.

Androgens↗
PubMed1998

Lymphangiectasia haemorrhagica conjunctivae.

PURPOSE: To re-describe a condition that has not been mentioned in the literature for more than four decades and to outline a new method of treatment of the pathology using an argon laser. METHODS: Nine patients were identified over a 2 year period who fitted a clinical picture consistent with the features of lymphangiectasia haemorrhagica. Three were treated for frequent recurrent haemorrhages with a newly developed technique using the argon laser and followed for up to 2 years. RESULTS: None of the three treated patients has had a recurrence of the condition to date. In the six untreated patients the condition resolved spontaneously after repeated attacks over between 8 months and 8 years. CONCLUSIONS: Lymphangiectasia haemorrhagica conjunctivae is probably more common than expected and may resolve spontaneously, but is readily amenable to treatment with the argon laser if attacks become frequent, uncomfortable or unsightly.

Adult↗
PubMed1997

Clinical assessment of a hand-held automated keratometer in cataract surgery.

PURPOSE: Pre-operative keratometry was performed on 32 eyes of 32 patients undergoing extracapsular cataract extraction with intraocular lens implantation, for calculation of intraocular lens power. In an additional 20 eyes of 20 patients post-operative keratometry was performed to guide selective suture removal. Readings from a manual keratometer and an automated hand-held keratometer were compared. METHODS: Pre-operative measurements were repeated three times on each subject to assess the repeatability of each machine. Mean-difference plots were performed to define the limits of agreement of the two machines. RESULTS: Repeatability was higher using manual keratometry (MK) than automated keratometry (AK). There was broad agreement between the two machines in pre-operative and post-operative assessment, although clinically significant differences are likely to occur in some cases. CONCLUSIONS: MK should continue to be used for routine pre-operative keratometry, with the AK providing a useful alternative when MK is not possible. AK is sufficiently accurate to allow its use in post-operative assessment of suture-induced astigmatism.

Astigmatism↗
PubMed1995

Gender and haplotype effects upon hematological manifestations of adult sickle cell anemia.

In Africa, the beta-globin gene cluster haplotype may be associated with variation of Hb F levels in subjects with sickle cell anemia (SS). These observations have not yet been conclusively confirmed in SS out of Africa, perhaps because of small sample sizes, the predominance of haplotype heterozygotes, and diverse influences, including gender, upon Hb F levels. We studied 384 adult African-American SS patients (mean age, 31 years) and explored the relationship of gender, beta-globin gene cluster haplotype, and alpha thalassemia to hematological values and Hb F levels. Both haplotype and gender influenced Hb F concentration. In the total sample, Hb F was higher in females than in males (8.2 vs. 6.5%). In 35 males who were either homozygous for the Senegal chromosome or had the Senegal/Benin haplotype, the mean percent Hb F (8.0%) was equivalent to the Hb F level in females with Benin and Bantu haplotypes (approximately 7.5%). Both females and males homozygous for the Senegal haplotype chromosome or with the Senegal/Benin combination had a significant increase in Hb F compared to other groups. In 44 Senegal/Senegal or Senegal/Benin females the Hb F was 10.9%, or 1.0 g/dl, the highest value observed in all primary analysis groups. Preliminary analyses suggested that the presence of a Bantu chromosome blunted the gender-associated difference in Hb F, but Hb F differences between females with the Senegal/Benin haplotype (11.2%) and the Senegal/Bantu haplotype (8.8%) were not statistically significant. Hemoglobin concentrations were higher in males than in females except in subjects with at least one Senegal haplotype chromosome, where hemoglobin levels were equal. As expected, alpha thalassemia reduced the MCV, increased hemoglobin concentration, and lowered reticulocyte counts, regardless of haplotype. Hb F levels were not affected by the presence of alpha thalassemia in any group. We conclude that gender and beta-globin gene cluster haplotype interact significantly in the modulation of Hb F and anemia in adults with SS.

Adult↗
PubMed1994

Acute angle closure glaucoma: relative failure of YAG iridotomy in affected eyes and factors influencing outcome.

The treatment of acute angle closure glaucoma has been influenced by the development of the YAG laser and its ability to perform iridotomies as an outpatient procedure. In this retrospective study the results of YAG iridotomy were compared with surgical peripheral iridectomy. When compared with surgical peripheral iridectomy patients, YAG iridotomy patients were at greater risk of proceeding to further surgery, with this risk being significantly associated with increasing duration of attack. The authors suggest that in selected cases, surgical iridectomy should be given consideration as a primary procedure.

Acute Disease↗