摘要:

Spatial contrast sensitivity was investigated in a group of 17 patients with macular degeneration or optic atrophy. It has been reported earlier that patients with optic atrophy may have reduced contrast sensitivity at low spatial frequencies without decrease of visual acuity, a phenomenon called ‘hidden visual loss’. The present study shows that also the opposite may be true: patients with macular degeneration or optic atrophy may have greatly decreased visual acuity and yet normal or nearly normal contrast sensitivity at low spatial frequencies and resonably good sensitivity at intermediate spatial frequencies. This phenomenon could be called ‘hidden vision’. In normal individuals and many visually impaired patients the spatial contrast sensitivity at high and intermediate spatial frequencies is equal when measured using grating fields of different size. In patients with central scotoma due to macular degeneration or optic atrophy contrast sensitivity is dependent on the size of the grating field: the maximal contrast sensitivity is higher when larger grating fields are used. The size of the smallest grating field that is needed for normal contrast sensitivity values at low spatial frequencies is one measure of visual impairment in this group of patients. Another measure of the function of the eccentric viewing area is the grating acuity which may also vary as a function of the grating fie

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1983.tb01409.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Contrast sensitivity for moving and stationary sine grating patterns was determined in central and peripheral parts of the visual field. The method was primarily developed as a possible screening procedure for visual defects in glaucoma. Contrast sensitivity to moving patterns seemed maximal both in central and in 10 degrees of eccentric viewing for square wave reversals of temporal frequencies 0.5‐5 Hz. We selected 2Hz for the clinical procedure. Further, we have determined normal central and peripheral contrast sensitivity in 10 subjects 61–71 years‐old, to serve as a basis for the glaucoma studies. We used this age group since glaucoma mainly affects elderly people. We confirmed that contrast sensitivity was higher for dynamic than for static presentation of gratings of low spatial frequencies (below 1 c/d) both centrally and peripherally. For patterns of medium or high spatial frequencies, dynamic and static stimuli were equally detectable. The absolute level of contrast sensitivity was higher centrally than peripherally in the interval 0.3–4 c/d. The lower visual hemifield exhibited greater sensitivity, for both static and dynamic gratings, than the up

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1983.tb01410.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

An operant preferential looking technique was successfully used for testing of visual acuity in mentally retarded children with visual dysfunction.

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1983.tb01411.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Computerized visual field testing with the Competer automatic perimeter including automatic profile perimetry revealed early glaucomatous field loss in 9 of 10 eyes with photographically demonstrable retinal nerve fibre layer (RNFL) defects after optic disc haemorrhages despite the fact than conventional routine perimetry had failed to do so. In 7 of these cases the Competer central pattern test was abnormal; in 2 cases field defects could be shown only when automatic high‐resolution static profile perimetry was performed and directed according to the information present in wide‐angle RNFL photographs. A field defect was also found in one of five eyes with no photographic RNFL changes. Visual field defects seem to occur in a higher proportion of cases with RNFL defects than was previously thought, but they can be very subtle and hard to find. There are, however, cases where in spite of the presence of an undisputable RNFL defect no visual field defects can be shown even with painstaking technique and conversely field defects may be present without RNFL defects. Automatic perimetry and RNFL photography complement each other in early detection and quantitation of glaucomatous dam

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1983.tb01412.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Simultaneous bilateral fluorescein angiography of the iris vessels (SIFA) was performed on 2 groups of patients. One group comprised previously untreated patients with elevated intraocular pressure who underwent a SIFA both before and after a 3 days' timolol treatment in one eye and pilocarpine treatment in the other eye. The other group consisted of glaucomatous patients treated with timolol for 4 to 24 (mean 11) months before the angiography. Short‐ or long‐term use of timolol neither caused, increased nor decreased leak of the dye from the iris vessels, either at the pupillary border, or in other areas of the iris. Dynamics of the blood flow also remained unaffected. Short‐term use of pilocarpine increased extrapupillary focal leakage in on

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1983.tb01413.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Compliance with pilocarpine eye drop therapy was studied in relation to different measures of visual ability and different features of the drug regimen. Neither visual ability, nor complexity of the drug regimen nor side effects were significantly releated to the patients' compliance with their pilocarpine therapy. Nevertheless, non‐compliance was significantly more common among patients who regarded the eye drops as very unpleasant than among patients who did not. This indicates that non‐compliance is related to the patient's perception of side effects and/or negative attitudes to the treatm

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1983.tb01414.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

A 51% increase in number of cataract extractions during the period 1970‐79 is found. Neither population growth nor changes in age structure could alone account for this increase. Other factors such as economic resource allocation, changes in indications for cataract surgery and increased demand appear to be involved in this increase. Two large danish data sources were examined to determine the age and sex specific cataract extraction rates 1977‐79. These rates are found to be in part equivalent to rates reported from England but substantially lower than rates found in USA. The age and sex specific rates are used as basis for estimation of number of extractions year 2000. A 60 to 80% increase is likely because of population growth in the older age groups, extention of indications for cataract surgery and more demand for good vision in old

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1983.tb01415.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

A method for individual endothelial cell analysis using modern microcomputer hardware and the program package “ENDO”, developed specially for this purpose, is described. To determine the areas and perimeters of individual cells the coordinates of cell apices are recorded directly from specular photomicrographs with a manual digitizer. To digitize 100 cells with this method takes on average 16 min. A new parameter for cell shape, called hexadev and derived from cell areas and perimeters, is introduced. The shapes of the individual cells are compared with the shape of an equilateral hexagon and the deviations from this reference shape are expressed in percentage. In addition, the program calculates 6 other morphological parameters for the cell sample analyzed. Accuracy and repeatability of the method are presented, Current status of individual cell analysis and previous attempts to describe cell shape are discus

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1983.tb01416.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Radial keratotomy was performed on Owl Monkey corneas using 8 incisions with sparing of a 3.5mm central pupillary area. Cornea endothelial membrane permeabilities were determined at 2 days, and 4 weeks, following the procedure using simultaneous flux determinations of3H‐labeled inulin and14C‐labelled dextran. Inulin permeability was increased 27% two days following the procedure, and had returned to levels comparable to the unoperated eye 4 weeks following the procedure. Dextran permeability was unaltered at both 2 days, and 4 weeks, following the procedure. This study has shown that radial keratotomy causes a transient reduction in endothelial barrier function with the production af physiologically significant ‘holes’ in the membrane in the immediate post‐operative period. The relationship of this physiological alteration to ultimate endothelial cell function is, at the present time

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1983.tb01417.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The endothelium was studied by light‐ and electronmicroscropy in a cryo‐preserved cornea transplanted to a woman with herpetic keratitis and removed after 18 months because of wound dehiscence and epithelialization of the anterior chamber. The graft was perfectly transparent and of normal thickness. Light microscopy revealed the existence of a continuous layer of endothelial cells, showing pronounced pleomorphism when examined in flat preparation, with large multinuclear cells between smaller more normal looking mononuclear cells. The heterogeneous cell pattern resembled that observable in vitro after freezing and 24 h of culture. The cells therefore are not considered to be in a steady state. The ultrastructure of the majority of the cells was similar to that of non‐cryopreserved endothelium. Cell cohesion took place by tight junctions, the intercellular spaces were of normal width. Ultrastructurally there was, however, a cellular heterogeneity, due to the occurrence of light cells with few organelles, but always with intact cell membranes. These cells probably represent slow death of endothelial cells, demonstrated by falling cell density during the 18 months between grafting and examination. We conclude from this study that cells surviving the freezing can maintain a clinically normal endothelial function for 18 months by forming a continuous quasistatic monolayer of tightly bound living

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1983.tb01418.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY