Purpose A new perimetry method is described to evaluate central vision under multiple hue, illumination, and contrast conditions; results are described for normal individuals using high-contrast targets. Methods For 70 normal eyes of individuals with varying age, the ETDRS chart acuity was determined as well as discriminated target perimetry using high-contrast targets presented for 250 ms at locations up to 101 eccentricity. Retesting was performed to evaluate for learning and repeatability for the thresholded acuity at each eccentricity. Results The ETDRS acuity averaged 1.15 ± 0.37 arc min minimum angle of resolution (MAR) with best correction (20/23 equivalence). At fixation, the thresholded acuity for high-contrast targets paralleled the ETDRS acuity and averaged 1.75±0.85 arc min MAR (20/35 equivalence), and declined with increasing eccentricity in a linear fashion to 5.81 ± 3.97 arc min (20/116 equivalent) at 101 eccentricity. Linear regression showed Vmar ¼ 1.74 þ 0.330 * eccentricity in degrees (R 2 ¼ 0.966, Po0.0001). Testing time required B8-10 min per eye. Repeated testing showed only minimal learning experience at the most peripheral locations. The test-retest 95% confidence limits of difference measured 1.12 arc mins MAR at fixation (64% of the mean) and remained approximately the same proportion to the mean thresholded acuity outwards to 101 eccentricity. Conclusion The methodology seems rapid and reliable for measuring discriminatory visual function of optotype targets throughout the central 201 diameter visual field.
Purpose This pilot study was undertaken to examine the relationships between clinical measures of visual function and anatomic changes occurring in the eyes treated with bevacizumab for choroidal neovascularization (CNV) due to age-related macular degeneration (AMD). Methods A retrospective review was conducted for 50 eyes that had been treated with at least three injections of bevicizumab for CNV due to AMD, and followed for at least 6 months. Vision outcomes included best-corrected ETDRS chart acuity, scored by best-line read (ETDRS line) and by total letters read (ETDRS letter), and two measures obtained from central acuity perimetry with 98% Michelson contrast targets, the best acuity within 61 of fixation (BA61), and global macular acuity (GMA), representing a weighted average of the acuities thresholded at all intercepts within a 101 radius of fixation. Assessment of anatomic outcomes included fibrosis, atrophy, and subretinal hemorrhage grading on fundus photography, CNV size, pigment epithelial detachment (PED) size and grading of CNV leakage on fluorescein angiography, and central retinal PED, and subretinal fluid (SRF) thickness on optical coherence tomography. Results Logistic regression analysis showed an association between the vision outcomes of EDTRS letter and BA61 with the change in SRF thickness (R 2 : 0.47 and 0.35, respectively). The outcome of the vision measurement of GMA was associated with the change in SRF thickness, in CNV thickness, and in CNV fibrosis grade (R 2 : 0.34). No association was noted between the outcomes of ETDRS line with the change in any anatomic outcomes. Conclusion Acuity perimetry outcomes in this study seemed to offer improved understanding of the relationship between the vision outcomes and the measured anatomic changes. It seemed that neither ocular coherence tomography nor fluorescein angiography alone offered sufficient morphologic markers for prediction of functional outcomes.
Application of MIRT modeling procedures is dependent on the quality of parameter estimates provided by the estimation software and techniques used. This study investigated model parameter recovery of two popular MIRT packages, BMIRT and flexMIRT, under some common measurement conditions. These packages were specifically selected to investigate the model parameter recovery of three item parameter estimation techniques, namely, Bock-Aitkin EM (BA-EM), Markov chain Monte Carlo (MCMC), and Metropolis-Hastings Robbins-Monro (MH-RM) algorithms. The results demonstrated that all estimation techniques had similar root mean square error values when larger sample size and higher test length were used. Depending on the number of dimensions, sample size, and test length, each estimation technique exhibited some strengths and weaknesses. Overall, the BA-EM technique was found to have shorter estimation time with all test specifications.
Purpose To evaluate the testing performance, reliability, and validity of a self-administered visual function questionnaire designed for a Palm Pilot in comparison with the interviewer-administered-National Eye Institute Visual Function Questionnaire-25 (NEI-VFQ-25) (interviewer-NEI-VFQ-25) and self-administered-NEI-VFQ-25 (self-NEI-VFQ-25). Method The interviewer-NEI-VFQ-25 was administered to 135 sequential patients who visited a retina clinic, followed on separate days by the Palm Pilot-Visual Function Questionnaire (PalmPilot-VFQ) and self-NEI-VFQ-25. Rasch analysis of ordinal difficulty ratings for the PalmPilot-VFQ was used to estimate interval measures of perceived visual ability. Reliability was determined by calculating Cronbach's a and test-retest intraclass correlation coefficients (ICCs). Concurrent validity was determined by calculating correlations of the PalmPilot-VFQ score with that of a general vision question. For evaluating convergent validity, the PalmPilot-VFQ was compared with the interviewer-NEI-VFQ-25, habitual-correction visual acuity (HCVA), and with two visual analogue scale (VAS) questions. Performance time and testability were compared among the three questionnaires. Results Rasch analysis eliminated two items in the PalmPilot-VFQ due to poor-fit statistics. The final items showed internal consistency (Cronbach's a ¼ 0.89) and test-retest reliability (ICC ¼ 0.79), as well as an excellent separation index (3.23 and 4.01) for item parameters with significant concurrent correlation (Po0.0001). On evaluating convergent validity, the PalmPilot-VFQ showed strong correlations with interviewer-NEI-VFQ-25, with the HCVA of the better-seeing eye, and with the VAS questions (P ¼ 0.0001). Ninety percent of the 135 patients (HCVA 420/200 in the betterseeing eye) could perform the PalmPilot-VFQ with their habitual correction or high-plus spectacles, but in significantly less time than either interviewer-NEI-VFQ-25 or self-NEI-VFQ-25 (Po0.0001). Conclusion The PalmPilot-VFQ seems to be a reliable, valid, interactive, computer-based, self-administered questionnaire that can be used routinely by physicians to evaluate functional vision disability in populations with a high prevalence of macular disease.
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