Biomedical subjects

H Hashemi

Publications and source records attributed to H Hashemi.

8 recordsLinked to original sources

PubMed2006

Uncorrected refractive errors and spectacle utilisation rate in Tehran: the unmet need.

AIM: To determine the prevalence of the met and unmet need for spectacles and their associated factors in the population of Tehran. METHODS: 6497 Tehran citizens were enrolled through random cluster sampling and were invited to a clinic for an interview and ophthalmic examination. 4354 (70.3%) participated in the survey, and refraction measurement results of 4353 people aged 5 years and over are presented. The unmet need for spectacles was defined as the proportion of people who did not use spectacles despite a correctable visual acuity of worse than 20/40 in the better eye. RESULTS: The need for spectacles in the studied population, standardised for age and sex, was 14.1% (95% confidence interval (CI), 12.8% to 15.4%). This need was met with appropriate spectacles in 416 people (9.3% of the total sample), while it was unmet in 230 people, representing 4.8% of the total sample population (95% CI, 4.1% to 5.4%). The spectacle coverage rate (met need/(met need + unmet need)) was 66.0%. Multivariate logistic regression showed that variables of age, education, and type of refractive error were associated with lack of spectacle correction. There was an increase in the unmet need with older age, lesser education, and myopia. CONCLUSION: This survey determined the met and unmet need for spectacles in a Tehran population. It also identified high risk groups with uncorrected refractive errors to guide intervention programmes for the society. While the study showed the unmet need for spectacles and its determinants, more extensive studies towards the causes of unmet need are recommended.

Adolescent↗

PubMed2005

TLR4 polymorphism in Iranian patients with brucellosis.

OBJECTIVE: Brucellosis is a zoonosis of both public health and economic significance in most developing countries. Polymorphisms in Toll-like receptor-4 (TLR4) have been reported to be associated with a blunted immune response to microbial pathogens. Information regarding any association between genetic variation of TLR4 and susceptibility to brucellosis is not available in the literatures. The main purpose of this research is to evaluate the role of polymorphic alleles of TLR4 gene in susceptibility to brucellosis. MATERIALS AND METHODS: In this case-control study, 198 patients with brucellosis and 111 healthy volunteers matched for sex, age and geographic area were evaluated by genotyping for polymorphism in TLR4 gene (Asp299Gly) using amplification refractory mutation system (ARMS)-PCR method. RESULTS: Allele 896G was more prevalent in patients with brucellosis compared to healthy controls (33.6% vs. 20.7%, P=0.000003). Also the frequency of G allele of TLR4 gene was significantly higher in male patients with brucellosis compared to the same sex in control group (36% vs. 21.7%, P=0.00005). Multiple logistic regression analysis demonstrated that male patients heterozygous at allele G gene had a significantly higher risk for brucellosis with an odds ratio of OR 2.89, 95% CI: 1.79-4.69, P<0.0001). CONCLUSION: This study is the first to show an association between genetic polymorphism in TLR4 gene and susceptibility to brucellosis.

Adolescent↗

PubMed2005

Distribution of intraocular pressure in healthy Iranian individuals: the Tehran Eye Study.

AIM: To provide data on the distribution of intraocular pressure (IOP) in an Iranian population. METHODS: Through a population based, cross sectional study, 4565 Tehran citizens were studied in the Tehran Eye Study. The findings from the participants (n = 3834) aged 10 years and older free of glaucoma diagnosis or suspicion who had undergone applanation tonometry examination are presented. All participants received a standardised protocol including applanation tonometry, fundus examination, demographic data, and an interview. IOP measurement was used to evaluate its distribution by age, sex, and some eye parameters. RESULTS: Mean (SD) IOP was 14.5 (2.6) mm Hg in the total population, 14.4 (2.7) in men, and 14.5 (2.5) in women. Mean (SD) IOP in people > or =40 years was 15.1 (2.9) mm Hg. IOP increased significantly with age and cup:disc ratio except for a fall in old age. This relation was also observed when individuals without diabetes or hypertension history were analysed. IOP increased with darker eye pigmentation except for blue/grey eyes. There was a non-linear increase in IOP from emmetropic to high myopic eyes. CONCLUSION: Age, iris colour, and cup:disc ratio were related to IOP but not to sex. The distribution of IOP in this study was different from various other studies in different geographical regions and it seems advisable to employ a geographical approach to normal IOP interpretation.

Adolescent↗

PubMed2004

The prevalence and causes of visual impairment in Tehran: the Tehran Eye Study.

AIMS: To determine the prevalence and causes of visual impairment in Tehran, Iran, through a population based study. METHODS: In a population based, cross sectional study, 6497 Tehran citizens were sampled from 160 clusters using a stratified, random, cluster sampling strategy. The eligible people were enumerated through a door to door household survey in the selected clusters and were invited. All participants were transferred to a clinic for an extensive eye examination and interview. Visual impairment was determined using presenting and best corrected visual acuity (low vision: visual acuity of less than 6/18 to 3/60 in the better eye; blindness: visual acuity of less than 3/60 in the better eye). RESULTS: Of those sampled, 4565 (70.3%) people participated in the study. The age and sex standardised prevalences of visual impairment on the basis of best corrected and presenting visual acuity were 1.39% (95% confidence interval (CI), 1.07 to 1.71) and 2.52% (95% CI, 2.07 to 2.97), respectively. 15 people (0.28%; 95% CI, 0.14 to 0.42) were blind with corrected vision while 22 (0.39%; 95% CI, 0.23 to 0.56) were blind with presenting vision. Using the corrected and presenting vision, the prevalence of low visual impairment was 1.11% (95% CI, 0.84 to 1.39) and 2.13% (95% CI, 1.71 to 2.55), respectively. The causes of visual impairment according to the best corrected vision were cataract (36.0%), macular degeneration (20.0%), and amblyopia (10.7%). However, according to the presenting vision, uncorrected refractive errors were the most frequent primary cause (33.6%) and cataract (25.4%), macular degeneration (12.7%), and amblyopia (8.2%) were the other main causes of visual impairment in the study sample. The prevalence of visual impairment was associated with advancing age and lower education. CONCLUSION: The results indicate that the burden of visual impairment is important and, although easily preventable, uncorrected refractive errors and cataract have a major role as causes of visual impairment in this population. Results also highlight the need for visual impairment prevention programmes, with emphasis on treatment of refractive errors and cataract.

Adolescent↗

PubMed1994

Practical induction heating coil designs for clinical hyperthermia with ferromagnetic implants.

Interstitial techniques for hyperthermia therapy of cancer continue to evolve in response to requirements for better localization and control over heating of deep seated tissues. Magnetic induction heating of ferromagnetic implants is one of several available techniques for producing interstitial hyperthermia, using thermal conduction to redistribute heat within an array of controlled temperature "hot sources." This report describes seven induction heating coil designs that can be used for producing strong magnetic fields around ferromagnetic seed implants located in different sites in the body. The effect of coil design on the extent and uniformity of the magnetic field is characterized, and appropriate electrostatic shield designs for minimizing electric field coupling to the patient are described. Advantages and disadvantages of each coil type are discussed in terms of the radiated fields, coil efficiency, and ease of use, and appropriate applications are given for each design. This armamentarium of induction coils provides the ability to customize magnetic field distributions for improved coupling of energy into ferromagnetic implant arrays located at any depth or orientation in the body. Proper selection of heating coil configuration should simplify patient setup, improve the safety of patient treatments, and pave the way for future applications of interstitial heating in sites that were previously untreatable.

Equipment Design↗

PubMed1993

The cerebral hyperperfusion syndrome: diagnostic value of ocular pneumoplethysmography.

PURPOSE: There were two purposes to our study. The first was to characterize the ocular hyperperfusion associated with carotid endarterectomy. The second was to relate ocular hyperperfusion to the clinical presentation of cerebral hyperperfusion syndrome. METHODS: This was a retrospective chart review of 2331 patients who underwent carotid endarterectomy at our institution between June 1978 and May 1991. RESULTS: Twelve of these carotid endarterectomies were associated with ocular hyperperfusion on the side of operation. Clinical evidence of cerebral hyperperfusion syndrome was observed in five of these 12 procedures. In these five patients there were two associated fatal intracerebral hemorrhages and one permanent coma. In the latter three patients the contralateral internal carotid arteries were totally occluded. CONCLUSION: Ocular hyperperfusion, as documented with ocular pneumoplethysmography, is useful in alerting the physician to the potential for development of the cerebral hyperperfusion syndrome.

Air↗

PubMedDate not supplied

The effect of hyperopic laser in situ keratomileusis on refractive accommodative esotropia.

PURPOSE: To evaluate the efficacy of laser in situ keratomileusis (LASIK) for discarding spectacles and simultaneously correcting ocular alignment in patients with refractive accommodative esotropia. METHODS: LASIK was performed on 20 eyes of 10 patients (mean age, 24.3 years; range, 11 to 43 years) using a Technolas 217C excimer laser. The target refraction was emmetropia. Visual acuity (uncorrected and best-corrected), refractive error, and ocular alignment were recorded before and after LASIK. Minimum follow-up was 12 months. RESULTS: The mean preoperative uncorrected and corrected angle of deviation was 37.1 prism diopters (PD) (range, 17 to 80; standard deviation (SD), 19.8)) and 14.74 PD (range, 0 to 50; SD, 12.9) of esotropia, respectively, which changed to 7.2 PD (range, 0 to 50; SD, 15.78) without correction postoperatively (p=0.005). Of 20 eyes, 15% lost one line of best-corrected visual acuity, 10% gained two lines, and 75% showed no change. CONCLUSIONS: LASIK could be considered an alternative treatment for patients with refractive accommodative esotropia with intolerance to glasses and contact lenses.

Accommodation, Ocular↗

PubMedDate not supplied

A quantitative corneal topography index for detection of keratoconus.

BACKGROUND: Detection of keratoconus has become a critical issue in patients who are potential candidates for refractive surgical procedures. In eyes with early stages of keratoconus, slit-lamp corneal changes are either absent or too subtle for detection, and keratometry may be normal. Videokeratography systems have greater sensitivity for detection of such cases, but interpretation of the topographic map is sometimes difficult, especially when pathologies with similar topographic patterns are suspected. We introduce an index using corneal topography for detection of keratoconus. METHODS: From March 1994 to December 1995, a total of 513 unoperated eyes, with no pathology other than keratoconus, from 283 consecutive patients were categorized into three groups based on slit-lamp examination and corneal topographic findings. Those with clinically obvious keratoconus were placed in the first group (53 eyes [10.3%]), those with keratoconus suspect comprised the second group (17 eyes [3.3%]), and the third group was that of normal eyes (443 eyes [86.4%]). In all videokeratographs of these eyes, the highest rate of corneal power changes (in diopters per millimeter) away from the apex (the point of maximum power) to the periphery was measured along its semimeridian. This index, called the "highest rate of steepening (HRS)", was statistically analyzed in the three groups. RESULTS: The mean +/- SD of highest rate of steepening was 3.60 +/- 1.70 D/mm (range 1.59 to 7.53 D/mm) in the clinically obvious keratoconus group, 1.59 +/- 0.21 D/mm (range 1.35 to 1.98 D/mm) in the keratoconus suspect group, and 0.72 +/- 0.31 D/mm (range 0.18 to 1.63 D/mm) in normal eyes. There was a highly statistically significant difference in the means of highest rate of steepening in the three groups (p < 0.0001). A small overlap in the highest rate of steepening ranges was shown among the three groups. Considering the first and second groups as cases of keratoconus, and 1.40 D/mm as the optimum cut-off value for highest rate of steepening, a sensitivity of 95.7% (67 out of 70 cases were detected), a specificity of 96.4% (16 false-positive cases), and an accuracy of 96.3% was obtained. CONCLUSION: The highest rate of steepening may be a useful measure for keratoconus screening with videokeratography. Validation is needed to evaluate its accuracy.

Adult↗