Biomedical subjects

Lene Martin

Publications and source records attributed to Lene Martin.

7 recordsLinked to original sources

PubMed2006

Visual field defects in prematurely born patients with white matter damage of immaturity: a multiple-case study.

PURPOSE: White matter damage of immaturity may affect visual, motor and cognitive functions. This multiple-case study presents standardized perimetry results in six teenagers and young adults born prematurely with visual dysfunction due to white matter damage of immaturity of pre- or perinatal origin. METHODS: Six subjects, aged 13-25 years, born at a gestational age of 28-34 weeks, with white matter damage of immaturity documented by MRI, and optic disc appearances documented by fundus photography, were examined with manual and computerized quantitative perimetry. RESULTS: All subjects had subnormal visual field (VF) function, although the depth and extension of the VF defects differed between subjects. The inferior VF function was more deviant than the superior in all cases. The concordance between the VF defects detected with the different techniques was good, although the static computerized techniques revealed slightly more abnormality. CONCLUSION: White matter damage of immaturity may affect the VF. The lower VF is often more affected than the upper. The abnormalities can be demonstrated by both manual and computerized perimetry.

Adolescent↗

PubMed2005

Rarebit and frequency-doubling technology perimetry in children and young adults.

PURPOSE: To describe the outcome of visual field examinations performed with rarebit (RB) and frequency-doubling technology perimetry (FDT) in children and young adults. METHODS: Twenty-one children (aged 6.5-12 years) and 30 teenagers and young adults (aged 14-20 years), participated in the study. RESULTS: Reliable RB examinations were carried out in 76% of the younger group and 90% of the older group. Corresponding values for FDT were 57% and 90-95%, respectively. The RB results were very similar to those previously obtained in adult subjects, while some subjects showed borderline values in FDT, depending on the criteria used. The RB perimetry was preferred by 88% of the examined subjects. CONCLUSIONS: Rarebit perimetry seems useful for visual field examination in children aged 7 years and over, if age-corrected normative data are established; this test was also preferred by the tested subjects. No adaptation or special instructions were needed and the children found it rather amusing.

Adolescent↗

PubMed2004

Algorithms for optimizing drug therapy.

BACKGROUND: Drug therapy has become increasingly efficient, with more drugs available for treatment of an ever-growing number of conditions. Yet, drug use is reported to be sub optimal in several aspects, such as dosage, patient's adherence and outcome of therapy. The aim of the current study was to investigate the possibility to optimize drug therapy using computer programs, available on the Internet. METHODS: One hundred and ten officially endorsed text documents, published between 1996 and 2004, containing guidelines for drug therapy in 246 disorders, were analyzed with regard to information about patient-, disease- and drug-related factors and relationships between these factors. This information was used to construct algorithms for identifying optimum treatment in each of the studied disorders. These algorithms were categorized in order to define as few models as possible that still could accommodate the identified factors and the relationships between them. The resulting program prototypes were implemented in HTML (user interface) and JavaScript (program logic). RESULTS: Three types of algorithms were sufficient for the intended purpose. The simplest type is a list of factors, each of which implies that the particular patient should or should not receive treatment. This is adequate in situations where only one treatment exists. The second type, a more elaborate model, is required when treatment can by provided using drugs from different pharmacological classes and the selection of drug class is dependent on patient characteristics. An easily implemented set of if-then statements was able to manage the identified information in such instances. The third type was needed in the few situations where the selection and dosage of drugs were depending on the degree to which one or more patient-specific factors were present. In these cases the implementation of an established decision model based on fuzzy sets was required. Computer programs based on one of these three models could be constructed regarding all but one of the studied disorders. The single exception was depression, where reliable relationships between patient characteristics, drug classes and outcome of therapy remain to be defined. CONCLUSION: Algorithms for optimizing drug therapy can, with presumably rare exceptions, be developed for any disorder, using standard Internet programming methods.

Algorithms↗

PubMed2004

New perimetric techniques: a comparison between rarebit and frequency doubling technology perimetry in normal subjects and glaucoma patients.

PURPOSE: To compare rarebit microdot perimetry (RB) with frequency doubling technology (FDT) perimetry in normal subjects and a group of patients with ocular hypertension or glaucoma, with age-matched controls. MATERIALS AND METHODS: : Eighty-one subjects (age 17-88 years) were examined. Twenty-seven of these were patients, aged 50 to 88 years, with ocular hypertension or suspected/manifest glaucoma in at least one eye. All subjects were examined with the RB and FDT perimetry, using the standard procedures, recommended by the respective manufacturer. RESULTS: All patients were able to perform the RB perimetry, but three patients could not perceive the strongest FDT stimulus. The concordance in RB and FDT classifications as normal/outside normal limits was 96% (Cohen's kappa = 0.90). A curvilinear (quadratic) relationship (Rsq = 0.75) was found between RB hit rate and FDT MD. All patients, who could perform both examinations, preferred the RB perimetry. CONCLUSION: In the current study, the information from the RB and FDT perimetry was almost completely equivalent. However, RB perimetry was preferred by the patients and seemed to have a larger dynamic range than FDT. The RB hit rate is apparently a straightforward and efficient measure of visual field function.

Adolescent↗

PubMed2003

Concordance of high-pass resolution perimetry and frequency-doubling technology perimetry results in glaucoma: no support for selective ganglion cell damage.

PURPOSE: To compare the results of frequency-doubling technology perimetry (FDT), assumed to test the magnocellular visual pathway, and high-pass resolution perimetry (HRP), assumed to test the parvocellular visual pathway, in patients with ocular hypertension or glaucoma. PATIENTS AND METHODS: Forty-eight consecutive patients with glaucoma or ocular hypertension, covering the entire range of optic nerve function from normal to severely damaged, were examined on the same day using FDT and HRP. RESULTS: There was a linear correlation between both global and local indices in FDT and HRP (r = -0.84 P<0.0001 and r = 0.8 P<0.001, respectively). The HRP and FDT classifications agreed in 32 of the 48 (67%) eyes (Cohen kappa = 0.5). There was no significant difference between the ability of the different techniques to detect abnormality. CONCLUSION: The observations in the present study indicate either that both cell populations are similarly affected by glaucomatous damage or that both methods measure activity in the same cell populations.

Adult↗

PubMedDate not supplied

Peripheral and central visual fields in 11-year-old children who had been born prematurely and at term.

PURPOSE: To examine the peripheral and central visual fields in children who had been born prematurely and at term. METHODS: Four groups of 11-year-old children were examined: group 1 included 24 children who had been born at term (control group); group 2 included 20 children who had been born prematurely without ROP; group 3 included 22 children who had been born prematurely with untreated ROP (stages 2 and 3); and group 4 included 21 children who had been born prematurely and underwent cryotreatment for severe ROP. Their peripheral visual fields were examined with Goldmann perimetry. Static high-pass resolution perimetry was used to evaluate their central visual fields within 30 degrees. RESULTS: The peripheral visual fields were constricted in children who had undergone cryotreatment (group 4), as compared with the other groups (1 to 3). We found no difference between the groups of children who had been born prematurely with or without ROP (groups 2 and 3) and the control group. The function of the central visual fields, expressed as neural capacity, was reduced in the children who had been born prematurely compared with the controls, significantly in their left eyes only. The children who underwent cryotreament did not differ from the other children who had been born prematurely in this respect. CONCLUSIONS: The peripheral visual fields were constricted in children who had undergone cryotreatment. It is uncertain whether this was caused by the treatment or by severe ROP. The central visual fields showed a tendency of reduced neural capacity in the children who had been born prematurely, reflecting a reduced density of retinocortical neural channels. However, this was not related to ROP or cryotreatment.

Child↗

PubMedDate not supplied

Visual function in young adults following intrauterine growth retardation.

BACKGROUND: Intrauterine growth retardation (IUGR) resulting in infants born small for gestational age is a known risk factor for neurologic deficits and may predispose to poor cognitive development later in life. We recently found an association between IUGR and a reduced neuroretinal rim area at 18 years of age. We evaluated the possible association between IUGR and visual function. SUBJECTS AND METHODS: We studied 26 subjects who had been born small for gestational age and 20 subjects whose birth weights were appropriate for gestational age (controls) using letter acuity thresholds, color vision testing, full-threshold frequency doubling technology perimetry, and rarebit perimetry at 18 years of age. gestational age had a rarebit hit rate below the normal range as compared with none of the controls (P = .006). These 8 subjects had a significantly smaller rim-disc ratio compared with the subjects who were small for gestational age who had a normal rarebit hit rate (P = .047). The frequency doubling technology indices did not differ significantly between the control group and the group that was small for gestational age, nor did the visual acuity, refraction, and color vision test results. CONCLUSION: These data indicate that IUGR is associated with an increased rate of impaired visual function, which can be detected by using rarebit perimetry but not frequency doubling technology perimetry, visual acuity, or color vision tests.

Adolescent↗