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Biomedical subjects

M Wolffe

Publications and source records attributed to M Wolffe.

9 recordsLinked to original sources
PubMed2006

Identification of the source of permanent glare from a three-piece IOL.

OBJECTIVE: To identify the source of unwanted glare images from a three-piece intraocular lens (IOL) implant following cataract surgery. METHOD: The IOL and posterior capsule were examined under mydriatic and nonmydriatic conditions using direct focal illumination from a slit lamp biomicroscope. Direct focal illumination was undertaken with both a narrow beam (0.1 mm in width) and small spot (0.1 mm in diameter) to identify the points at which the glare images were stimulated. While observing the location of the beam with the slit lamp biomicroscope, the patient indicated when the glare images were stimulated. RESULTS: The nasal haptic insertion into the optic was identified as the source of temporal line images arising from lights such as headlamps from oncoming cars and street lamps. The adjacent edge of the IOL was also identified as the likely source of additional cob web-like light rays. CONCLUSIONS: The haptic insertions in three-piece IOLs may, under certain conditions, interfere with light entering the pupil and produce extraneous images. Large mesopic pupils and decentred IOLs are conditions that increase the likelihood of unwanted glare images.

Aged↗
PubMed2006

Characterizing reflections from intraocular lens implants.

OBJECTIVE: To develop a test method for characterizing glare from intraocular lenses (IOLs) and to confirm a clinical finding that the haptic insertion in the optic of a three-piece IOL produces extraneous line images. METHOD: The method consists of directing a collimated Gaussian laser beam to various parts of the IOL to be tested in a water-filled model eye. Reflected images produced in the retinal plane are photographed with a digital camera. RESULTS: A test method was developed to characterize the source of glare images from IOLs. The test method developed was used to confirm a clinical finding that the haptic insertion in the optic of a three-piece IOL produces extraneous line images. CONCLUSIONS: The method developed can be used to characterize and pin point the source of extraneous glare images from intraocular lens implants. The haptic insertion in the optic of a three-piece IOL has been identified as a source of line images.

Female↗
PubMed1995

Role of peripheral vision in terms of critical perception--its relevance to the visually impaired.

It is recognised that discrimination of fine detail is dependent on an intact macula with the peripheral retina being responsible for motion detection. There is evidence, however, to suggest that the peripheral retina does play a critical part in such discrimination. Studies of the performance of visually impaired school children have revealed levels of visual perception far exceeding anything that would be expected for individuals so severely handicapped. The art work of visually impaired youngsters was compared with the predicted results based on their visual acuity. The results showed detail that in theory could not have been resolved with such low acuity levels. All the youngsters had dense central scotomata. The peripheral retina, therefore, must have been involved in the discrimination of such detail. These results have implications not only for the visually impaired in terms of what they are capable of doing, but also for our understanding about the way the visual cortex processes information from the peripheral retina and the use that it makes of this relatively poor quality information.

Blindness↗
PubMed1985

The employment and education of the partially sighted in the period immediately after leaving special school.

Initial results are reported of a major study undertaken to determine factors which could be used to predict employment success of partially-sighted school leavers. The sample involved 355 individuals from 13 schools for the partially sighted taken from three successive final academic years and followed up 1 year after leaving school. Questionnaire techniques were used, the response rate being 85.6%. Analysis revealed that 55.6% sought or experienced employment and 44.4% undertook further education. Eighty-seven per cent of those seeking employment obtained jobs alongside the normally sighted. Only 12 leavers remained totally unemployed. Forty-seven per cent were still in their initial employment.

Adolescent↗
PubMed1984

The occupational success of visually handicapped adolescents in the first year after leaving school for the partially seeing.

Data on 355 partially sighted youngsters was obtained during the final year of schooling by clinical assessment and by perusal of appropriate school records. Approximately 12 months after leaving school, a postal questionnaire was used to obtain information on employment record. A response rate of 85.6% was achieved. A measure of occupational success, based on job tenure, was derived for the 169 respondents who had sought employment. Correlational analysis was undertaken between occupational success and 46 visual, biographical, psychological and educational parameters. Small but statistically significant correlations were obtained for the sex of the youngster, academic qualifications, one measure of distance visual acuity and the youngsters' attitudes to visual impairment and to the interaction with the normally sighted.

Adolescent↗
PubMed1982

Residual vision in the low vision patient--some concepts.

The ability to function with residual sight--visual ability--varies widely among individuals with low vision. The theoretical nature of visual ability, however, is poorly understood. Various components of visual ability are defined in an attempt to advance the understanding of this subject.

Blindness↗
PubMed1980

Screening optometric patients by questionnaire: methods of improving response.

Mailed questionnaires are a quick and cheap means of obtaining data, but they have two disadvantages. They often produce low response rates irrespective of the nature of the group sampled, and they may seem inappropriate for clinical samples with visual problems. High response rates are needed for reliable results and valid conclusions. This paper presents a set of techniques enabling high response rates to be obtained. It also reports research showing that such techniques are appropriate even for the partially sighted.

Adolescent↗