ISSN:1040-5488    

出版商:OVID    

年代:2002

数据来源: OVID

ISSN:1040-5488    

出版商:OVID    

年代:2002

数据来源: OVID

ISSN:1040-5488    

出版商:OVID    

年代:2002

数据来源: OVID

ISSN:1040-5488    

出版商:OVID    

年代:2002

数据来源: OVID

ISSN:1040-5488    

出版商:OVID    

年代:2002

数据来源: OVID

ISSN:1040-5488    

出版商:OVID    

年代:2002

数据来源: OVID

ISSN:1040-5488    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD) can cause rapid and severe central vision loss in many older people. Until recently, the only treatment proven beneficial was thermal laser photocoagulation, which was applicable to only a small subset of patients. Furthermore, the thermal laser damaged the retina overlying the CNV, which is especially problematic for lesions involving the foveal center. Photodynamic therapy is a new treatment consisting of intravenous infusion of a drug that is then activated by a low-energy laser, causing damage to CNV. Photodynamic therapy with verteporfin (Visudyne, Novartis AG) has been shown to reduce the risk of moderate and severe vision loss in patients with predominantly classic subfoveal CNV secondary to AMD. With the advent of verteporfin therapy, eye care providers will play an increasingly important role in managing patients with AMD, especially in the early detection and rapid referral of appropriate cases.

ISSN:1040-5488    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

An implantable miniaturized telescope (IMT) for low vision has recently been developed. Surgically inserted into only one eye of patients with bilateral central visual loss, the IMT provides a nominal magnification of 3.0× and a field-of-view of 6.6° (9.2° for the 2.2× magnification version). Theoretical concerns have been raised regarding the ability of patients to function with a large interocular magnification difference, the impact of the monocular restriction of the field-of-view, and the impact of this design on depth perception. This article addresses these concerns regarding the design of the IMT in comparison with spectacle-mounted telescopes and combined intraocular lens/spectacle (or combined contact lens/spectacle) telescopic systems. The effective field-of-view (as determined by the combination of both the field-of-view and the field-of-fixation), the effects of head motion and the vestibular reflex, and the disruption of stereo depth perception with a monocular device are considered here. Physiological optics considerations of these issues show that the IMT may have important advantages over other designs of magnification devices for patients with age-related macular degeneration.

ISSN:1040-5488    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Background.Correction of infant aphakia with conventional soft and rigid designs induces significant amounts of positive spherical aberration.Methods.Different levels of positive spherical aberration were induced by rigid lenses positioned close to the eye. Visual acuity and depth of focus were measured for twelve young adult subjects.Results.Positive spherical aberration acts to produce an increase in relative depth of focus, but because of the reduction of best visual acuity, there is a concurrent decrease in absolute depth of focus. As the spherical aberration increases, there is a progressive loss of best-corrected visual acuity.Conclusions.The correction of spherical aberration in contact lenses for infant aphakia provides the best theoretical optical conditions for normal ocular growth and visual development. We provide examples of the optimal aspheric surfaces to minimize spherical aberration in contact lenses for infant aphakes.

ISSN:1040-5488    

出版商:OVID    

年代:2002

数据来源: OVID