摘要:

The pathogenesis of myopia in humans is a complex and multifactorial process. Hereditary and environmental factors are both important in determining the ultimate refraction of the eye, although their relative importance has yet to be elucidated. With the advent of reliable animal models for experimental myopia, the environmental factors that influence ocular growth and the physiological and biochemical mechanisms underlying these processes are beginning to be understood.

ISSN:1040-8738    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Dynamic retinoscopy for the objective examination of accommodation was described in the ophthalmologic literature in the 1890s but is rarely used in ophthalmology today. The technique has been extensively investigated by the optometric profession, however, sometimes with confusing, and sometimes with useful, results. It can be of value in screening infants for astigmatism and anisometropia, in detecting incomplete cycloplegia, in detecting abnormalities oi accommodation, and probably in determining the treatment strategy for eyes with amblyopia and deficient accommodation.

ISSN:1040-8738    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Contrast sensitivity can be measured in various ways that, depending on the clinical situation, may or may not reflect similar information. Under pathologic conditions, there will be differences in static grating plates versus temporally alternating oscilloscope sine waves versus Snellen acuity letters of decreased contrast. Choosing an appropriate methodology for the information needed is recommended. Orientation of gratings may give different results depending on the location of brain lesions. The “normal” side may be abnormal in amblyopia and hemianopia, a reflection of the binocularity of vision. Increased intracranial pressure with pseudotumor causes a contrast sensitivity abnormality that reverses to normal within days of shunting. Refraction is important for Snellen (letter) and contrast sensitivity but less so in grating, and it influences contrast sensitivity significantly. Recognition contrast sensitivity targets (letters) degrade faster with eccentric viewing than gratings, a finding important in low-vision aid therapy.

ISSN:1040-8738    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

This paper reviews recent advances in low vision and its rehabilitation. There has been a rapid expansion of the literature in this diverse field. This article reviews and provides annotated references on statistics on blindness and low vision, on orientation and mobility and their relation to residual vision, and on the controversial issue of allowing visually impaired persons to drive. New approaches to assessing residual vision are described, and there is discussion of patterns of the progression of visual field and visual acuity losses in retinitis pigmentosa. Current advances in electronic imaging systems are beginning to be applied to assist the visually impaired.

ISSN:1040-8738    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The ability of contact lens materials, and lenses made from these materials, to permit the diffusion of oxygen, has been measured for twenty years. Interest in oxygen diffusion through contact lenses has become increasingly important as our understanding of the oxygen requirements of the cornea (to maintain its normal metabolism) has developed in parallel. We herein review both the current techniques and controversies related to in vitro measurements, and also discuss both the known critical oxygen values and some of the physiological consequences of reduced oxygen availability.

ISSN:1040-8738    

出版商:OVID    

年代:1991

数据来源: OVID

ISSN:1040-8738    

出版商:OVID    

年代:1991

数据来源: OVID

ISSN:1040-8738    

出版商:OVID    

年代:1991

数据来源: OVID

ISSN:1040-8738    

出版商:OVID    

年代:1991

数据来源: OVID