ISSN:0275-5408    

DOI:10.1111/j.1475-1313.1986.tb00712.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

ISSN:0275-5408    

DOI:10.1111/j.1475-1313.1986.tb00713.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Abstract—A schematic cortical projection of the human visual field is combined with the concept of dipole planar generators to provide a theoretical model of the scalp distribution of evoked potentials from visual field stimuli. The computations illustrate the importance of gyral surfaces as the principal generators of recorded evoked potentials. Taking several zones of the visual field projection on the striate area as an example, the model is used to produce horizontal profiles of evoked potential amplitude. This indicates the limitation and possibilities of mapping the cortical projections in man and relating these to perimetric finding

ISSN:0275-5408    

DOI:10.1111/j.1475-1313.1986.tb00714.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Abstract—Displacement thresholds for continuous oscillatory movement of a grating, subtending 2 cycle deg‐1, were measured for square‐, triangular‐and sine‐wave oscillation over the frequency range 1–20 Hz. Without reference lines, thresholds were highly dependent upon temporal frequency and oscillation waveform. With reference lines, thresholds were dependent upon oscillation waveform but not frequency. Greatest sensitivity was shown to square‐wave oscillation and least to triangular‐wave. Results are discussed in terms of velocity‐and displacement‐analysing systems. Increasing the spatial frequency of the sinusoidally oscillating grating had little effect on disp

ISSN:0275-5408    

DOI:10.1111/j.1475-1313.1986.tb00715.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Abstract—We studied the effect of 1.25 D of optical blur on visual acuity at luminances ranging from photopic to low mesopic levels. Optical blur reduces acuity at all luminances tested, this reduction being fourfold at a high photopic level (170 cd m‐2) and twofold in low mesopia (0.017 cd m‐2). The reduction of visual acuity with blur at low luminances is greater than might be expected from a spatial frequency analysis of v

ISSN:0275-5408    

DOI:10.1111/j.1475-1313.1986.tb00716.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Optical pachymetry was performed on 15 nearly emmetropic and 15 myopic subjects with accommodation fully relaxed and with 3.00 and 6.00 dioptres of stimulus to accommodation. No significant difference was found between the change in anterior chamber depth per dioptre of stimulus between the two groups. This is in agreement with theoretical considerations, which suggest that a change in the length of the vitreous does not much affect the optical efficiency of the crystalline lens.

ISSN:0275-5408    

DOI:10.1111/j.1475-1313.1986.tb00717.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Abstract—A method named quasi‐static recording of accommodation is introduced. While accommodative stimulus (AS) is slowly changed over a wide range with a constant velocity (0.2 D s‐1), accommodative response (AR) is continuously measured. AS and AR, respectively, are recorded on the abscissa and the ordinate of an x ‐ y recorder to produce a “quasi‐static” response/stimulus curve.This method was applied to 28 monocular amblyopic and formerly amblyopic subjects, and the findings were compared with those from their sound eyes. The recordings and subsequent analysis show reduced accommodative amplitude and reduced accommodative accuracy in amblyopic eyes, similar to those reported in previous static measurements of accommodation. In about a half of the amblyopic eyes, the recordings reveal that the fluctuations of accommodation are greater as the target becomes closer. Increased microfluctuation associated with a loss of sensitivity to change of contrast is discussed. This phenomenon suggests that increased microfluctuation is directly associated with reduced performance. In three recovered amblyopes, the accommodative functions were considerably reduced, while the other 10 subjects showed improved functions. It is suggested that, in some cases, the abnormal accommodation is the cause of

ISSN:0275-5408    

DOI:10.1111/j.1475-1313.1986.tb00718.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Abstract—Contrast sensitivity was measured in pseudophakic and aphakic patients. No difference could be demonstrated between the contrast sensitivities of patients with anterior chamber/iris‐supported and posterior chamber intraocular lenses (IOLs). Little difference was found between pseudophakics and aphakics. Interocular contrast ratios in five pseudophakic patients with normal fellow eyes revealed a range of contrast attennation characteristics which may be attributed to the IOL and corneal and posterior capsule transmiss

ISSN:0275-5408    

DOI:10.1111/j.1475-1313.1986.tb00719.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Abstract—It has frequently been reported that the spontaneous ocular oscillation in congenital nystagmats is less intense for near viewing than during distance fixation. The reason for this effect was sought, and the influences of monocular adduction, convergence and accommodation acting separately and synergistically were assessed. The frequent assumption that nystagmus intensity (amplitude and frequency) is determined by convergence angle (either symmetrical or asymmetrical) was confirmed, and it was found that binocular viewing was not necessary. An identical effect on nystagmus intensity could be created for distance fixation by the use of base‐out prisms, and these were prescribed for constant wear in two congenital idiopathic nystagmats. Although nystagmus intensity was constantly reduced, no concomitant increase in binocular contrast sensitivity or Snellen visual acuity occur

ISSN:0275-5408    

DOI:10.1111/j.1475-1313.1986.tb00720.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Abstract—(1) The effect of fluoromethalone 0.1% suspension (FML), clobetasone butyrate 0.1% (Eumovate) and betamethasone phosphate 0.1% (Betnesol) in post‐operative inflammation was studied in 60 eyes (50 patients) in a randomized trial.(2) No significant differences were noted, although two patients required higher penetration steroids than FML or Eumovate.(3) Betnesol seemed to have a greater tendency to cause raised intraocular pressure than FML. In this series, however, the authors are unable to comment on differences between Eumovate and Betne

ISSN:0275-5408    

DOI:10.1111/j.1475-1313.1986.tb00721.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY