摘要:

Letter charts were used to measure visual acuity and peak contrast sensitivity of the short wavelength sensitive (S cone)-pathway. The accommodative response was monitored retinoscopically. The mean visual acuity (0.92 logMAR) and spatial contrast threshold (8.7%) were comparable to values reported elsewhere, and variability was relatively low. Both S-pathway acuity and contrast sensitivity were selectively reduced in one patient with central serous retinopathy and in another with retinitis pigmentosa. These simple spatial tests offer an additional index of S-pathway integrity which will be useful for detection and evaluation of ocular disease.

ISSN:1040-5488    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Utilizing the principal diagnostic criterion of an absent or cloudy Meibomian gland secretion upon repeated expression, patients with Meibomian gland dysfunction (MGD) were selected to participate in a study of the efficacy of lid scrubs and massage in the treatment of MGD. Twenty-one patients with contact lens intolerance unrelated to lens, care system, or health factors were randomly assigned to treatment of one eye with common clinical therapy for MGD. After 2 weeks of treatment, gland expression, biomicroscopy, staining, comfort, and fluorescein breakup time were assessed in a masked manner. Analyzed using a paired-data t-test, the results indicated a significant increase in mean tear film breakup time (BUT) in the treated eye at followup compared to baseline (mean increase=4.0 s, p=0.0001). The control eye demonstrated no significant change (mean increase=0.2 s, p=0.5955). These objective results were corroborated by reports of improved subjective comfort with contact lens wear after therapy.

ISSN:1040-5488    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

ABTRACTTear film proteins are known to adsorb to new hydrogel contact lenses. Using a radioiodine tracing technique, proteins were shown to adsorb to contact lens surfaces. The quantity of protein adsorbed to the contact lenses within 2 to 4 h was 1 to 3 /µg/lens. The degree of protein adsorption varied from lens-to-lens depending in part on the water content of the lens. High water content ionic lenses bound the most protein, whereas lower water content and nonionic lenses bound less protein. Enzyme cleaning of the protein-coated contact lenses removed about 75% of the adsorbed protein. When the enzyme-cleaned lenses were reincubated with protein, similar quantities were quickly readsorbed within a similar period of time. The rate of readsorption appeared to vary with the type of enzyme used to clean the lenses. Hydrogel lenses adsorb protein from the tear film rapidly and irreversibly. Cleaning the lenses has only a partial and temporary effect on the bound protein. The lens-bound proteins could become partly denatured during their binding to the lenses. These observations suggest a possible role for such proteins in ocular sensitivity to contact lenses.

ISSN:1040-5488    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Maxwellian-view projection systems are used clinically to evaluate visual acuity in cataract patients because they allow the clinician to direct a beam of light around any localized opacity. However, theory predicts that, as the beam is displaced from the visual axis, acuity will suffer with those instruments using white light due to the effects of ocular chromatic aberration. Using three commercially available Maxwellian-view instruments, we examined the decline of visual acuity with beam decentration in the clear pupil of normal subjects. With all three instruments (Lotmar interferometer, Randwal interferometer, and the Potential Acuity Meter) acuity fell by a factor of 3 for beams placed near the edge of a dilated pupil. Control experiments with monochromatic light indicated that lateral chromatic aberration was the primary cause of acuity loss with the two interferometers, but other off-axis aberrations also contributed to the acuity loss with the Potential Acuity Meter. A detailed analysis of the beam in the pupil plane indicates that the beam's complex structure may be altered if the beam strikes the iris or an opacity in the ocular media. These findings indicate that potential acuity may be significantly underestimated with polychromatic Maxwellian-view systems.

ISSN:1040-5488    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

We investigated the effects of selected disinfecting solutions on the structural integrity of Goldmann applanation tonometer tips. Hydrogen peroxide, isopropyl alcohol, dilute sodium hypochlorite (household bleach), and glutaraldehyde-phenate (Sporicidin) have been used for disinfecting tonometer tips. However, the effect of these solutions on the tips' structure has not been fully investigated. Haag-Streit tonometer tips were soaked separately for 30 days (723 h) in 5 different solutions and distilled water, approximately 1 working year of routine use (310 days by 14 patients per day). During the soaking period, the tips were regularly removed from solution, examined through a slitlamp, measured with vernier calipers, and photographed to monitor for structural degradation. Alcohol was the only solution that damaged the tips. The other disinfecting solutions appear to be safe for use on the tips after the equivalent of 1 working year of routine use.

ISSN:1040-5488    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Among the 80 subjects who were recruited with normal retinal and neural function, 54 had cataract and a visual acuity (VA) better than 6/24. The 26 age-matched subjects had clear media. Contrast sensitivity (CS) at low and intermediate spatial frequencies was measured using the Pelli-Robson letter chart. Two measures of glare disability (GD) were obtained using the Mentor Brightness Acuity Tester (BAT) in conjunction with a logMAR VA chart and the Pelli-Robson chart. Although CS is predominantly affected at high spatial frequencies in early cataract, we found that some subjects had reduced scores on the Pelli-Robson chart. This CS loss could not be predicted from VA measurements and was particularly found in subjects with posterior subcapsular cataract. High GD scores were found in a number of subjects with relatively good VA and could not be predicted from results of VA or CS. We suggest that CS and GD measurements using the Pelli-Robson chart and the BAT provide valuable information regarding the management of patients with early cataract.

ISSN:1040-5488    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Contrast sensitivity (CS) was measured in children ages 3 to 7 years using the Vistech Contrast Sensitivity distance chart (VCTS 6500). The purpose of the study was to determine how effectively the technique could be used with young children and to establish normative data for this age group. Of 286 children participating in a vision screening, the contrast sensitivity function (CSF) was measurable on 241 (84%) under binocular conditions and 229 (80%) under both binocular and monocular conditions. The 219 binocular CSF's and 208 monocular CSF's obtained from visually normal children were used to establish normative data and then compared to similar data from 50 visually normal young adults. The results indicated that there is an effect of age between 3 and 7 years, children are significantly less sensitive than adults, and adult-like levels of CS are not yet reached at 7 years of age. In addition, although the children's mean contrast thresholds fell within the norms provided with the VCTS 6500, the variability in the children's CSF's precludes using the Vistech data for diagnostic purposes in the young. The normative data are presented to assist the clinician in evaluating CS in young children when using the VCTS 6500.

ISSN:1040-5488    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

A retrospective survey of 5000 active aircrew records was performed at 12 United States Air Force (USAF) bases to obtain information about the prevalence of spectacle wear and refractive error. The data revealed that 27.4% of pilots and 51.5% of navigators/weapons systems operators (Nav/WSO) required spectacles when flying. Of the spectacle-wearing pilots, 12.4% required bifocals. Myopia was the predominant refractive error and a relatively large percentage of aircrew members had astigmatism of 0.75 D or more, e.g., 33.1% of pilots. At the time of entry into the USAF, refractive error data were clustered around emmetropia with a definite skew toward hyperopia.

ISSN:1040-5488    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

A 66-year-old white male presented with complaints of redness of his left eye, blurred vision, lid edema, and an intermittent throbbing pain above his left eye for 4 days. Significant clinical findings included mild hyperemia and edema of the left upper lid, marked engorgement and tortuosity of the conjunctival and episcleral vessels, mild chemosis, and extreme limitation of the extraocular movements of the left eye in all directions of gaze, especially adduction. This eye also showed a measurable proptosis with positive retropulsion. Pupillary responses and color vision were normal in both eyes. A CT scan revealed an enlarged medial rectus muscle, including its tendinous insertion with a normal cavernous sinus. On the basis of the clinical findings and the CT scan, a diagnosis of orbital pseudotumor was made. The patient was treated with high dose systemic prednisone, which resulted in a dramatic improvement of symptoms and signs.

ISSN:1040-5488    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Although previous reports of ischemic optic neuropathy resulting from herpes zoster have appeared in the literature, these reports have not been convincing of a true optic neuropathy. The case presented is a true posterior ischemic optic neuropathy due to inflammation of the medial posterior ciliary artery, diagnosed on the basis of a deep, steep-sided altitudinal visual field defect. The herpes zoster infection also resulted in retinitis, damage to the iris sphincter, and corneal scarring. The effects of herpes zoster on the visual system are reviewed.

ISSN:1040-5488    

出版商:OVID    

年代:1990

数据来源: OVID