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Biomedical subjects

A L Hård

Publications and source records attributed to A L Hård.

10 recordsLinked to original sources
PubMed2002

Large variability in performance IQ associated with postnatal morbidity, and reduced verbal IQ among school-aged children born preterm.

AIM: To assess cognitive ability in a population-based group of prematurely born school-aged children and to relate these findings to postnatal morbidity. METHOD: The study group consisted of a cohort of 51 children born preterm, 43 (26 boys, 17 girls) of whom were available for psychological evaluation At evaluation, their median age was 10 y (range 8-11 y). They were all born between 1988 and 1991, with gestational age less than 29 wk (median 27, range 24-28). Their median birthweight was 1060g (range 450-1450). The Wechsler Intelligence Scale for Children (WISC-III) was used, and the test results were compared with those of a standardized, age-matched, normative group of children. RESULTS: Thirteen children (30%) performed below average [intelligence quotient (IQ) < 80] for Full Scale IQ (FSIQ). Thirty-six children had a Verbal IQ (VIQ) below the mean value of 100 [84%, 95% confidence interval 73-95%], p < 0.0001. The Performance IQ (PIQ) was within the expected range of a normal population, although a large variability was observed. Discrepancies between VIQ and PIQ of more than 15 IQ units were found in 42% of the children. High postnatal morbidity (days with assisted ventilation, number of blood transfusions) and low birthweight standard deviation scores (SDS) were associated with lower PIQ than VIQ, while low postnatal morbidity and high birthweight were associated with higher PIQ than VIQ. CONCLUSION: This cohort of preterm children had reduced overall verbal capacity independent of morbidity, and a large variability in performance capacity that was associated with postnatal morbidity. The findings suggest that there are different mechanisms influencing the outcome of verbal and performance capacity in preterm children.

Blood Transfusion↗
PubMed2000

Visual function in school-aged children born before 29 weeks of gestation: a population-based study.

The aim of this study was to assess visual function, including visual perception, in a geographically-based population of school-aged children, with a median age of 7.2 years (range 5.1 to 9.3 years), born before 29 weeks of gestation to mothers living in Goteborg, Sweden. Fifty-one preterm children participated in the study, six of whom had known brain lesions. Visual acuity, visual fields, stereoacuity, and visual perception were tested. The Test of Visual Perceptual Skills Revised (TVPS-R, Gardner 1996) was used to measure visual perception, and the results were compared with those of 50 term (control) subjects. Six percent of the preterm children were visually impaired, with a visual acuity of less than 0.3 (6/18), while 42% of all the preterm children and 34% of those without known brain lesions had a total score below the 5th centile of the reference material for the test, compared with 14% of the control subjects. In conclusion, visual-perceptual problems seem to be common among very preterm children and should be screened for and assessed before the children start school.

Child↗
PubMed2000

Ocular fundus abnormalities in children born before 29 weeks of gestation: a population-based study.

PURPOSE: Preterm birth has been found to be associated with increased morbidity of the central nervous and vascular tissues. To investigate the influence of preterm birth on the optic disc and retinal vessels, we examined the ocular fundus in school-aged children born very preterm. METHODS: A prospective, population-based study was performed in 50 very preterm children (median age 7 years, range 5-9 years) with a median gestational age at birth of 27 weeks (range 24-28 weeks) and a median birth weight of 1055 g (range 450-1520 g). The ocular fundus was examined by ophthalmoscopy in 50 children, and the optic nerve and retinal vessel morphology was evaluated by digital image analysis of ocular fundus photographs in 45 of these children. RESULTS: The median optic disc area was significantly smaller (p = 0.0002) in the preterm children compared with a reference group. There was no difference in cup area and, consequently, the rim area was significantly smaller (p = 0.0002) in the preterm children. Children with early signs of brain lesions commonly had a rim area below the median of the reference group. Preterm children also commonly had an abnormal retinal vascular pattern that was independent of a previous history of retinopathy of prematurity. CONCLUSION: Very preterm birth was associated with subnormal optic disc and rim areas and an abnormal vascular pattern. The findings clearly demonstrate the effect of preterm birth on the development of these structures. The long term clinical prognosis of these findings has yet to be determined.

Adolescent↗
PubMed1997

Ocular fundus morphology in preterm children. Influence of gestational age, birth size, perinatal morbidity, and postnatal growth.

PURPOSE: To determine the influence of gestational age, birth size, perinatal morbidity, and postnatal growth on fundus morphology in preterm children using digital image analysis of fundus photographs. METHODS: Thirty-nine preterm children (mean postmenstrual gestational age, 29.1 weeks; range, 24.6 to 32) were included in the study. Thirty-nine healthy children, born at term, were used as control subjects. Fundus photographs were obtained at a mean age of 4.8 years (preterm) and 6.1 years (control subjects). RESULTS: There was no difference in optic disc, excavation, or peripapillary crescent area between the two groups. In the group of preterm children, a large optic disc size was associated with a low birth weight (rs = -0.29, P = 0.07), duration of assisted ventilation (rs = 0.43, P = 0.006), and number of blood transfusions (rs = 0.33, P = 0.04). The girls born prematurely showed a negative relation between the length of gestation and the area of the optic disc (r2 = 0.28, P = 0.009). No such relation was found in boys. The preterm children had increased tortuosity of retinal vessels (P < 0.001 and P < 0.002 for arteries and veins, respectively) and reduced number of vascular branching points (P < 0.001) compared with those of the control subjects. There were no associations between these vascular abnormalities and the perinatal and postnatal variables studied. CONCLUSIONS: No difference in optic disc morphology between preterm children and control subjects was found. However, preterm birth seems to affect the retinal vascular pattern close to the optic disc, independently of retinopathy of prematurity. Among the girls born preterm, optic disc size was negatively correlated to gestational age.

Birth Weight↗
PubMed1995

Do we have optimal screening limits in Sweden for vision testing at the age of 4 years?

The purpose of this study was to evaluate the Swedish screening criteria for referral of children to ophthalmic care after visual acuity testing at the age of 4 years. The screening limit has generally been 0.8. To what extent do children with 0.65 in each eye (0.65/0.65) or 0.65 in one and 0.8 in the other (0.65/0.8) at the age of 4 years have visual defects needing early treatment? Sixty-three children who had failed screening underwent orthoptic and ophthalmologic evaluation. Twenty-four patients (38%) saw 0.65/0.65 or 0.65/0.8 and were studied further. None of them had manifest strabismus. Refractive errors were minor except in 2 patients who had significant hyperopia. Twenty-two of these 24 patients returned for reevaluation at the age of five years and that time 18 of them saw 0.8 or more without treatment. Our findings suggest that children with visual acuity of no less than 0.65 and no more than one line's difference between the eyes at 4 years of age seldom have visual defects needing treatment.

Child, Preschool↗
PubMed1993

Glare measurements before and after cataract surgery.

The efficacy of cataract surgery in improving visual performance was evaluated in 10 patients by measuring changes in intraocular light scatter, contrast sensitivity and glare induced visual loss. Two different methods were used to estimate these functions before and after cataract extraction with implantation of a monofocal posterior intraocular lens. By one method intraocular light scattering was assessed. By the other, letter contrast sensitivity and glare induced visual loss were determined. Preoperatively most patients had various glare problems, glare induced visual loss and increased intraocular light scatter. Following surgery the letter contrast sensitivity increased by a factor of 3 or more (mean 4.3). The glare problems diminished or disappeared after surgery, although several patients still had increased intraocular light scattering and glare induced visual loss compared to normals. Postoperatively the contrast sensitivity both with and without glare had increased to a level where the glare induced visual loss did not create any visual problems.

Adult↗
PubMed1992

Comparison of two glare measurement methods through light scattering modeling.

Two methods used for evaluation of glare in patients with opacities of the ocular media are compared. One is a low contrast letter test and the other is a direct light scattering meter. Theoretical expressions for the measures obtained from the two different glare tests are derived in terms of the point spread function. Measurements on healthy test persons wearing diffusive glasses with known light scattering properties were in good agreement with the theory. Data from 26 cataractous eyes are presented and discussed in light of the theory.

Adult↗
PubMed1990

A new glare test based on low contrast letters--evaluation in cataract patients.

A new simple glare test was designed and evaluated regarding clinical usefulness and reproducibility. The ability to recognize letters of equal size and varying contrast was determined with the absence and presence of glare sources above and below the letters. Ten patients with cataract, visual acuity of at least 0.3 and glare problems, and three age matched controls were tested, as well as one patient with glare complaints and exophoria, one with lens subluxation and one with cataract and no glare problem. The test was found to be cheap and simple to produce and useful for clinical testing. Normal eyes had no detectable reduction of letter contrast sensibility with glare. All cataractous eyes had a letter contrast sensitivity without glare that was well below that of the controls and under glare conditions they all had a drop in visual function that was unrelated to their visual acuity. The reproducibility was of a magnitude similar to that of other low contrast letter tests. Our conclusion is that this test will be a valuable tool in the evaluation of cataract patients providing information not only about glare-induced visual loss but also about contrast sensitivity, separating eyes with increased intraocular light scattering from normal eyes.

Adult↗