ISSN:1040-5488    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

The purpose of this 3-year prospective study is to compare high school-aged subjects, randomized into wearing soft contact lenses and spectacles, in terms of ocular health, refractive status, and self-esteem. This report focuses on ocular response to the lens care systems used through the first 18 months of the investigation. Eighty-four subjects were randomly fitted with either CibaSoft Visitint or CibaSoft-Standard Visitint contact lenses. Three lens care systems, Ciba Vision AOSept Disinfection/Neutralization Solutions (AOSept), Opti-Free Rinsing, Disinfection, and Storage Solution (Opti-Free), and ReNu Multi-Purpose Solution (ReNu), were randomly prescribed to the subjects wearing contact lenses. Limbal congestion, conjunctival hyperemia, corneal staining with fluorescein, corneal edema, and corneal neovascularization were graded at dispensing and at 6-, 12-, and 18- month visits. There were no significant differences among the groups at baseline. At 6 months statistically significant difference (p=0.0131, Kruksal-Wallis) was found for fluorescein staining of the cornea among the systems. At 12 months significant differences were found for corneal edema (p=0.0404, Kruksal-Wallis) and neovascularization (p=0.0315, Kruksal-Wallis) among the systems. At 18 months generalized conjunctival hyperemia was significantly different (p=0.0234, Kruksal-Wallis) among the systems along with greater limbal congestion (p=0.0015, Kruksal-Wallis) and neovascularization (p=0.0238, Kruksal-Wallis). In conclusion, the cornea, limbal vessels and the conjunctiva respond differently to the lens care systems used in this study. Overall, patients using AOSept showed less corneal staining and inflammatory response than patients using ReNu and Opti-Free.

ISSN:1040-5488    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Using computer-assisted videokeratoscopy we measured corneal astigmatism and compared these results over a range of corneal zone diameters with total ocular astigmatism derived by subjective refraction. Videokeratoscopes permit a more detailed analysis of the power distribution within a given corneal surface area, enabling comparison to the total astigmatism for equivalent aperture sizes. Although there were significant individual variations, the group average data supports the traditional view of a linear relation between corneal and total astigmatism. This was true across the range of apertures tested from 2 to 7 mm, with the coordinates of the relation being consistent with that of the modified Javal's rule; namely a slope of 1 and an intercept of approximately 0.50 D against-the-rule residual astigmatism.

ISSN:1040-5488    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Foveation periods are brief intervals in the congenital nystagmus (CN) waveform when the image is on or near the fovea and eye velocity is relatively slow. The purpose of this study was to determine how visual acuity depends on image velocity for foveation periods of different durations. Visual acuity was measured using high-contrast, single Landolt Cs in four normal observers during image motion simulating that in jerk nystagmus. The “simulated foveation periods” ranged from 20 to 100 ms in duration and 0 to 167s in velocity. The “critical velocity” was defined as the velocity during simulated foveation periods that produced a just-noticeable worsening of acuity (0.05 and 0.1 logMAR) from that in the zero-velocity condition. Critical velocity increased from approximately 3°/s for simulated foveation durations between 100 and 40 ms to approximately 5°/s for a simulated foveation duration of 20 ms. Critical velocities increased further when the targets were presented peripherally or with optical blur, to introduce an additional acuity loss. A consequence of these findings is that less recovery of acuity should be expected when retinal image motion is reduced in individuals with CN if a sensory acuity deficit coexists.

ISSN:1040-5488    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Lens retention in metal and zyl safety frames was tested using both a high mass (500 g), low velocity impact (HM-LV), and a low mass (1.04 g), high velocity impact (LM-HV) for piano polycarbonate lenses of various thicknesses. The results showed that the metal safety frames retained lenses better than the zyl (p / 0.01) after a HM-LV impact. For the LM-HV impact, metal and zyl frames performed equally (p=1.00). Lens thickness was not a factor in lens in frame retention for the HM-LV impact (p=0.958). However, for the LM-HV impact, 1.6-mm thick lenses were more easily displaced than lenses with thicknesses of 2.0, 2.4, and 3.2 mm (p=0.003).

ISSN:1040-5488    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Background. Two to four percent of epileptics have their seizures triggered by flickering light, an effect which may be wavelength-dependent. We evaluated a patient with a long-standing history of light-induced petit mal seizures to determine if the seizures were triggered more effectively by a particular range of wavelengths and to determine whether this information could be used in the optometric management of such patients. Methods. Flickering lights of different wavelengths but equal luminance were presented while the patient's electroencephalogram (EEG) and subjective reports were monitored. Results. The EEG results were not significantly different for different wavelengths, but the patient reported that longer wavelength light induced stronger seizures more consistently. Based on these results we concluded that the patient might benefit from spectacles tinted to exclude transmission of red light. The patient was given 4 pairs of 85% transmission spectacles, which differed only in lens tint (red, yellow, green, and blue), to try over a period of time. The patient felt that the tinted lenses were not dark enough to decrease his seizures effectively and he has opted to wear standard sunglasses. Conclusions. We feel this case shows that patients with light-induced seizures can benefit from optometric consultation. Because the patient's subjective report identified the clearest wavelength effect, we feel that it is reasonable for the general practitioner to suggest deeply tinted lenses to reduce the frequency of seizures in these patients.

ISSN:1040-5488    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Patients with congenital nystagmus (CN) often have associated conditions (e.g., strabismus, high astigmatism, and binocular inefficiency) that also impair visual acuity. Unfortunately, individually used techniques directed at reducing nystagmus have generally produced only slight increases in Snellen acuity. We present case reports of six patients with nystagmus seen in our clinic (University of Houston, College of Optometry) to illustrate the use of problem-specific management to improve visual acuity and/or binocular function. The results suggest that a comprehensive management strategy should include treatment of all associated conditions as well as therapy to improve the characteristics of the nystagmus wave form.

ISSN:1040-5488    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Using a recently discussed three-point Vernier alignment test,1'2 data were obtained on patients with macular dysfunctions with and without a pseudo-nuclear cataract 6/60 (20/200) at the Aravind (Free) Eye Hospital, Madurai, India. The pseudo-cataract caused measurably and predictably reduced Vernier alignment thresholds, and necessary modifications deemed to be necessary in the protocol for later study are defined.

ISSN:1040-5488    

出版商:OVID    

年代:1996

数据来源: OVID

ISSN:1040-5488    

出版商:OVID    

年代:1996

数据来源: OVID

ISSN:1040-5488    

出版商:OVID    

年代:1996

数据来源: OVID