ISSN:1040-5488    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

External ocular disease associated with human immunodeficiency virus (HIV) infection can often be overlooked by the eye care practitioner. Different types of external ocular disease can be an indication of the patient's overall immune status as well as the stage of HIV infection. The external ocular sequelae of HIV infection can be of visual consequence for the patient. Eye care practitioners need to become familiar with these conditions. The diagnosis and management of the following ocular conditions associated with HIV infection are reviewed: conjunctival microvascular disease, dry eye, allergic conjunctivitis, microsporidial keratoconjunctivitis, herpes zoster ophthalmicus, herpes simplex keratitis, molluscum contagiosum, fungal keratitis, bacterial keratoconjunctivitis, and Kaposi's sarcoma (KS).

ISSN:1040-5488    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

In this case report, we present 3 years of longitudinal, refractive component data for a young adult who became myopic and progressed in myopia (late-onset myopia, LOM) during that period. We found a high correlation between refractive error and axial length (AL). The axial elongation was a consequence of the change in the vitreous chamber depth (VCD). Furthermore, the change in AL and VCD corresponded quantitatively to the change in refractive error. Corneal curvature change was not correlated with refractive error change. These findings support the suggestion that VCD is the refractive component that changes in LOM development.

ISSN:1040-5488    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Presbyopia is caused by changes in the visco-elastic properties of the lens or the choroid or both. Far-tonear (FN) accommodation dynamics are dominated by the properties of the lens, whereas near-to-far (NF) accommodation dynamics depend on the properties of the lens as well as the choroid. The aim of this study was to gain more insight into the cause of presbyopia by analyzing how FN and NF accommodation dynamics change as a function of age. Changes in axial lens thickness during accommodation were measured in vivo using continuous ultrasonographic biometry. The measurements were analyzed with the use of a biomechanical model of the mechanism of accommodation. Fitting the model to the responses yields time constants of FN and NF accommodation. The time constants FN and NF increase with age at an approximately equal rate: 7 ms/year (±1.8 SEM) and 6 ms/year (±1.6 SEM), respectively. This result supports a lenticular cause of presbyopia. In addition, estimations of the lens damping coefficients at different ages are given for the first time: the damping coefficient of the lens increases 20-fold between 15 and 55 years of age.

ISSN:1040-5488    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Residents of nursing homes do not have the same access to health care as do others. A retrospective study of the records of optometric examinations at three nursing homes with demographics presumably similar to those of most nursing homes in the United States was performed in order to determine the prevalence of vision anomalies in this population and to determine if optometric intervention was beneficial. Sixty-five percent of the patients received an immediate benefit from the optometric examination in either treatment or referral to another health care provider for an undetected or poorly controlled health problem. We concluded that this type of service was needed by the patients in the nursing homes and was professionally rewarding to the optometrist providing it.

ISSN:1040-5488    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

The assessment of soft contact lens fit by observation of the lens behavior on the eye is one of the most common procedures undertaken in contact lens practice. Nevertheless, the guidelines for doing so have been derived empirically with little or no research into the usefulness of these observations. Over 2000 evaluations of soft contact lens fit were analyzed to determine the predictive value of various indicators of contact lens fit, namely: subjective comfort, lens centration, postblink movement (PBM), version and upgaze lag, and tightness assessed by the push-up test. The receiver-operator characteristic (ROC) curves were prepared for each variable by plotting sensitivity values against false positive rates (FPRs) for various cut-off points. Sensitivity was defined as the proportion of “bad” fits correctly identified by a given variable; FPR was defined as the proportion of “good” fits incorrectly identified as bad fits. With each fitting variable, the optimum cut-off point and its corresponding sensitivity and FPR were determined from the ROC curves. Subjective comfort was found to be of little value in identifying tight fitting lenses but was of some limited value in identifying loose fitting lenses, particularly high water content (HWC) lenses. The push-up test was the most accurate single test of lens fit acceptability having a high sensitivity for both tight (92%) and loose (80%) lens fits. Assessment of PBM was a sensitive indicator of tight fitting lenses (95%), but was a poor indicator of loose fitting lenses, having a low sensitivity (51%). Assessment of version lag showed better sensitivity than upgaze lag in assessing loose fits, whereas upgaze lag showed better sensitivity for tight lens fits. Lens centration was of no predictive value in identifying tight fitting lenses but, as expected, was of some value in identifying loose fitting lenses. The results of this study enable a critical reassessment of the procedures that practitioners follow when fitting soft contact lenses.

ISSN:1040-5488    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Purpose. A masked investigation of the relation between performance on various vision tests and reading was conducted with 90 kindergartners (mean age 5.73 years) and 91 first graders (mean age 6.76 years) from a middle class, suburban, elementary school near Cleveland, Ohio.Methods.Vision testing included the Modified Clinical Technique (MCT), ±2.00 D flipper lenses with red/green suppression check for accommodative facility, and Randot for stereoacuity. Reading performance was independently evaluated with the Metropolitan Achievement Test 6 Reading Test and teachers' assessments.Results.The results revealed that accommodative facility was predictive of successful reading performance in 7-year-olds (p=0.0431), first graders (p=0.0125), and in the entire subject group when age (p=0.0254) or grade (p=0.0224) was controlled. Failure on the MCT was significantly associated with decreased reading skill in 5-year-olds (p=0.0431). In addition, stereoacuity worse than 100 sec arc (p=0.0316), MCT failure plus stereoacuity worse than 50 sec arc (p=0.0316), and accommodative facility (p=0.0155) were predictive of whether children of average intelligence would show successful or unsuccessful reading ability.Conclusions.Thus, visual performance was significantly related to reading performance even in children of average intelligence when IQ was partially controlled. Also, the predictive value of the MCT for reading achievement could be improved by the addition of a referral criterion for stereoacuity. This would make the results of MCT screening more readily applicable to educators.

ISSN:1040-5488    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Background. Many theories of myopia etiology suggest differences in accommodation and convergence in children who become myopic. Several studies have found differences in accommodation and convergence in myopes and emmetropes. Only one previous study examined accommodation and convergence before youth onset myopia. Methods. A cohort of initially emmetropic children was given eye and vision examinations at 6-month intervals for 3 years. The data collected included fusional vergence ranges at 4 m and 40 cm, and relative accommodation findings with a target at 40 cm. These clinical accommodation and vergence test findings were compared in children who became myopic (became-myopic group) to children who did not (remained-emmetropic group). The mean test findings were used to construct a zone of clear single binocular vision (ZCSBV) for each group. Results. The midpoint between the 40-cm fusional vergence range blur points was more convergent in the became-myopic group (+5.8 A compared to +3.2 A in the remained-emmetropic group; p<0.004). The positive relative accommodation (PRA) finding was less in magnitude in the became-myopic group (-.46 D) than in the remained-emmetropic group (-.04 D), the difference being significant at the 0.02 level. Conclusions. The ZCSBV near blur points were more convergent in the children who became myopic as indicated by the more convergent position of the midpoint of the near fusional vergence range. The lower value for the PRA test in the became-myopic group duplicates the same result reported in a previous study for retrospective longitudinal private practice data

ISSN:1040-5488    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Background. Some contemporary theories of the etiology of youth onset myopia suggest differences in accommodation and convergence function. Previous studies have related esophoria to various aspects of myopia development. This paper examines whether differences in phorias exist before the onset of myopia. Methods. A cohort of initially emmetropic children had eye and vision examinations at 6-month intervals for a period of 3 years. Dissociated phorias were measured by the von Graefe method. These prospective data were analyzed by: (1) comparing phorias in children who became myopic to those in children who remained emmetropic; (2) determination of sensitivity and specificity of phorias to distinguish between children who became myopic and those who did not; and (3) determining the change in phorias with time. These same analyses were also performed as additional analyses of some previously published retrospective private practice data. Results. Distance phorias were not significantly different in the became- myopic and remained-emmetropic group by the Mann Whitney U test in either the private practice data or the prospective data. The near phoria was more convergent in the became-myopic group than in the remained-emmetropic group in the private practice data (p<0.02 by Mann Whitney U test). In the prospective data there were proportionately more children who became myopic outside the near phoria range of 3 A exo to 1 A eso (p<0.05 by )£ test). In both data sets the near phoria showed an eso shift with time in the children who became myopic, beginning before and continuing after the onset of myopia. The children in the remained-emmetropic groups did not show eso shifts in near phoria. Conclusions. A near phoria which is not close to orthophoria appears to be a risk factor for youth onset myopia, but sensitivity and specificity were not as high as those for other variables such as corneal power, axial length to corneal radius ratio, positive relative accommodation (PRA), and midpoint of the near fusional vergence

ISSN:1040-5488    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Background. We conducted a study to compare variables in children who were initially emmetropic and became myopic to those in children who remained emmetropic. This paper examines parental history of myopia in the two groups of children. Methods. A cohort of initially emmetropic children was given eye and vision examinations at 6-month intervals for 3 years. Data on parental history of myopia were obtained by questionnaire. Results. A greater proportion of children in the became-myopic group had myopic parents compared to children in the remained-emmetropic group. The sensitivity for onset of myopia was 0.95 and specificity was 0.38 if at least one parent was myopic. A sensitivity of 0.36 and a specificity of 0.87 were found for both parents being myopic. There was a significant association between parental history of myopia and development of myopia in the children in the study (p<0.01 by x2for categorization of whether neither, one, or both parents were myopic for children in the became-myopic and remained-emmetropic groups). Conclusion. Parental history of myopia is a risk factor for the development of myopia

ISSN:1040-5488    

出版商:OVID    

年代:1996

数据来源: OVID