Biomedical subjects

Lillemor Wachtmeister

Publications and source records attributed to Lillemor Wachtmeister.

3 recordsLinked to original sources

PubMed2004

Background light adaptation of the retinal neuronal adaptive system. II. Dynamic effects.

The dynamic effects of continuous exposure to light on the neuronal adaptive system of the retina, as indicated by the oscillatory response (OPs) of the electroretinogram (ERG) were studied in the albino rat. Digitally filtered OPs and the a- and b-waves of the corneal ERG were simultaneously recorded in dark adaptation, during continuous light adaptation to four levels of background light (BGL) changing in steps of two log units from 1.43 x 10(-6) cd/m2, referred to as 'low and high scotopic, low and high mesopic' levels. Exposed to 'high scotopic' BGL the total oscillatory response (SOP) significantly enhanced within the first minute, whereas the amplitudes of the a- and b-waves were unaffected. In 'low mesopic' BGL the SOP increased within the first minute, whereas the a- and b-waves significantly decreased. 'High mesopic' BGL instantaneously and profoundly reduced both the SOP and the slow potentials. The individual OPs changed in amplitudes mainly within the first minute of BGL. In general, the earlier OPs (O1 and O2) reacted more to the two 'scotopic' BGL levels, whereas the later OPs (O3 and 04) were more affected by the relatively brighter two 'mesopic' conditions. In conclusion, the rapid increase of the OPs within the first minute of 'high scotopic' and 'low mesopic' BGL exposure may represent a rudimentary light adaptational effect in the rod-dominated rat retina. These findings also suggest that the neuronal adaptive mechanism of the retina seems to be a robust system, probably attaining preservation of visual abilities in the rat on exposure to light.

Adaptation, Ocular↗

PubMed2003

Retinal function in Bothnia dystrophy. An electrophysiological study.

Using prolonged dark adaptometry, standard dark adaptation (DA) and prolonged DA full-field electroretinograms (ERGs), we analysed the retinal function in patients with Bothnia dystrophy (BD), a variant of recessive retinitis punctata albescens (RPA). A compromised rod and cone function, a likely dysfunction of the Müller cells, and indications of disturbed neuronal function of the inner retina, were found. With prolonged DA, a gradual increase in retinal sensitivity to light and an improvement of the ERG components occurred. The findings indicate a prolonged synthesis of photopigments, retardation of the visual process in the retinal pigment epithelium (RPE), and a loss of retinal cells, probably starting at a relatively early age in BD.

Adolescent↗

PubMed2002

Change of subjective visual function in first-eye cataract patients when the rate of surgery increases in a population.

BACKGROUND: The increasing demand for cataract surgery has stimulated interest in outcome research and the potential public health impact of the intervention. OBJECTIVE: To determine the impact of an increased rate of first-eye cataract surgery on visual acuity (VA) and subjective visual ability/disability, before and after surgery, in a geographically defined population. RESEARCH DESIGN: A prospective, observational study. SUBJECTS: All patients who had first-eye cataract extraction at one clinic during two separate 1-year periods. Five hundred seventy-six patients had surgery in 1997, and 353 had surgery in 1992 (17.2 and 10.6 per 1000 population 65 and older, respectively). MEASURES: Best-corrected VAs were measured, and the patients answered self-administered questionnaires, before and after surgery. The questionnaires focused on the patients' subjective difficulties performing some common vision-dependent activities, such as reading, television-viewing, orientation, etc. RESULTS: In 1997 compared with 1992 the VA of the eye to be operated was on average better (chi2 for trend; P<0.0001), and the subjective visual disability was less before surgery (mean disability index 6.9 vs. 7.5; P<0.0001). There was also a smaller percentage of mature cataracts (15% vs. 23%; P<0.0001). After surgery the VA of the operated eye was better in 1997 (chi2 for trend; P<0.001), but there was no difference in improvement of subjective visual ability, nor change in subjective visual disability, compared with 1992. The patients' expectations and actual postoperative improvement of their ability to cope with daily life were higher in 1997 (chi2 for trend; P<0.0001 and P<0.001). CONCLUSIONS: A higher frequency of first-eye cataract surgery in a population was before surgery associated with an on average better VA of the eye to be operated, a less perceived visual disability regarding some common vision-dependent activities, a lower percentage of mature cataracts and thus earlier surgery. Consequently, a higher rate of surgery would likely be associated with a lesser amount of visual impairment because of cataract in the population.

Aged↗