How accurate is an LCD screen version of the Pelli–Robson test?

Zeri, Fabrizio; Calcatelli, Paolo; Funaro, Eleonora; Martelli, Marialuisa; Naroo, Shehzad A.

doi:10.1007/s10792-017-0609-0

Cited by 11 publications

(3 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They concluded that the newly developed numbers CS charts were inexpensive and could replace the Mars CS chart [1]. Zeri et al [11] checked the accuracy and repeatability of the computerized Pelli-Robson chart displayed on LCD systems against its standard printed version and found that the computer test is not interchangeable with the standard chart. Mohammadi et al [2] examined the degree of agreement between the CS results of the Freiburg visual acuity and contrast test (FrACT) and the Monpack3 device (Metrovision, Perenchies, France) in both amblyopic and normal eyes.…”

Section: Introductionmentioning

confidence: 99%

Comparison of CSV-1000 and Metrovision contrast sensitivity tests in normal eyes

Tahkor¹,

Shandiz²,

Khorasani³

et al. 2021

Med Hypothesis Discov Innov Optom

View full text Add to dashboard Cite

Background: Measuring contrast sensitivity (CS) allows a better understanding of the visual performance of the human eye. This study aimed to examine the correlation and agreement between the results of two sinewave grating-based CS measurement methods, Metrovision and CSV-1000, in normal eyes. Methods: This cross-sectional, comparative study was performed between December 2018 and April 2019, at an optometry clinic. Subjects underwent comprehensive ocular examinations, which included pupil reflexes, subjective refraction, external eye examinations, smooth pursuit eye movement assessment, the cover–uncover test, and detailed slit-lamp examination of the anterior and posterior segments. Metrovision and CSV-1000 were employed to assess CS under photopic conditions. The correlation and agreement of the results of the two tests were evaluated. Results: CS was measured for 104 normal eyes for 3, 6, 12, and 18 cycles per degree (cpd) spatial frequencies (participants’ mean age ± standard deviation: 37.3 ± 26.4 years). The CSV-1000 measurements were significantly higher for the 3 and 6 cpd spatial frequencies (both P = 0.01); however, at higher spatial frequencies, CS scores were similar. The highest and lowest differences between the two tests were recorded for the 3 cpd spatial frequency and 18 cpd spatial frequency, respectively. Except for the 3 cpd spatial frequency, in both eyes, the findings correlated significantly between the CSV-1000 and Metrovision (P < 0.05). The narrowest and widest limits of agreement between the two tests were found for the 12 and 3 cpd spatial frequencies, respectively. Conclusions: The CSV-1000 method estimated CS higher than the Metrovision method, mostly at lower spatial frequencies. Furthermore, the agreement between the two methods was greater at higher spatial frequencies than at lower frequencies. This should be kept in mind when using the two methods interchangeably in visual screening.

show abstract

Section: Introductionmentioning

confidence: 99%

Comparison of CSV-1000 and Metrovision contrast sensitivity tests in normal eyes

Tahkor¹,

Shandiz²,

Khorasani³

et al. 2021

Med Hypothesis Discov Innov Optom

View full text Add to dashboard Cite

show abstract

“…On the other hand, it suffers from the limitations of LCDs, mainly represented by the lack of low levels of contrast ratios 18 . The CS grating test measurements provided by the Vision Chart have not yet been investigated (only the Pelli-Robson test performed with this instrument has been analyzed and found to offer repeatable measurements) 19 . Therefore, the aims of this study were to define a normative database of these measurements and to validate them by assessing their repeatability and determining their responsiveness to cataract surgery.…”

Section: Introductionmentioning

confidence: 99%

Precision and Normative Values of a New Computerized Chart for Contrast Sensitivity Testing

Savini

Calossi

Schiano-Lomoriello

et al. 2019

Sci Rep

View full text Add to dashboard Cite

The purpose was to define a normative database for a grating test for contrast sensitivity, based on a chart monitor with high-definition liquid crystal display, and validate its measurements by assessing their repeatability and determining responsiveness to cataract surgery. Three samples were analyzed: (1) healthy volunteers to assess the repeatability of measurements, (2) healthy subjects to develop the normative database, (3) patients undergoing cataract surgery. All subjects were tested with the grating contrast sensitivity test (Vision Chart, CSO) at 1.5, 3, 6, 12 and 18 cycles per degree. The instrument software progressively reduces the contrast of the gratings according to the Quick Estimate by Sequential Testing (QUEST) procedure. In the subjects of the first sample, three consecutive measurements were taken and repeatability was assessed on the basis of the intra-session test-retest variability and the coefficient of variation. The test offered high repeatability, with test-retest variability ranging between 0.05 and 0.23 Log CS and the coefficient of variation between 0.61 and 4.21%. Normative data did not show a normal distribution. The highest median values were observed at 1.5, 3 and 6 cycles per degree frequencies. At these frequencies a ceiling effect was evident. In cataract patients, postoperative values showed an improvement at all spatial frequencies. In conclusion, the new contrast sensitivity test provides repeatable measurements that can be used for clinical purposes. In patients with healthy eyes and good vision, attention has to be paid to the ceiling effect.

show abstract

“…There are also psychophysical methods to determine a gamma luminance function visually, as, for example, described by To et al 6 This report will show that using a gamma-fitted (approximate) luminance function instead of the actual (exact) luminance function may give increasingly larger errors in contrast when displaying stimuli with smaller contrasts. This might also be (part of ) the reason why investigations such as those of Thayaparan et al 7 and Zeri et al 8 did not find a good correlation between a paper and a display version of a contrast sensitivity test for small contrasts.…”

mentioning

confidence: 98%

Display Characterization for Contrast Sensitivity Testing

Wit¹

2023

Optom Vis Sci

View full text Add to dashboard Cite

SIGNIFICANCEContrast sensitivity measurements using a computer display have been reported to lack accuracy when displaying small contrasts. This report investigates if the characterization/calibration of display luminance may contribute substantively to these kinds of described inaccuracies.PURPOSEThis study aimed to investigate what errors in contrast sensitivity may result from characterizing a display by fitting a gamma curve through physical or psychophysical luminance measurement data.METHODSThe luminance functions of four different in-plane switching liquid crystal displays (IPS LCDs) have been measured for all 256 gray levels (the actual luminance function). This has been compared with a gamma-fitted luminance curve (the gamma luminance function). Calculated are the errors in displayed contrast that may arise when assuming the gamma luminance function instead of the actual luminance function.RESULTSThe amount of error differs considerably between the displays. In general, for large contrasts (Michelson logCS <1.2), the error is acceptable (<<0.15 log unit). However, for smaller contrasts (Michelson logCS >1.5), the error may become unacceptably high (>0.15 log unit).CONCLUSIONSTo improve the accuracy of testing contrast sensitivity with an LCD, it is necessary to fully characterize the display, measuring the luminance of each gray level instead of fitting a smooth gamma function through limited luminance data.

show abstract

How accurate is an LCD screen version of the Pelli–Robson test?

Abstract: Computer-generated versions of Pelli-Robson test, displayed on LCD systems, do not provide accurate results compared to classic Pelli-Robson printed version. Clinicians should consider that Pelli-Robson computer-generated versions could be non-interchangeable to the printed version.

Cited by 11 publications

References 38 publications

Comparison of CSV-1000 and Metrovision contrast sensitivity tests in normal eyes

Comparison of CSV-1000 and Metrovision contrast sensitivity tests in normal eyes

Precision and Normative Values of a New Computerized Chart for Contrast Sensitivity Testing

Display Characterization for Contrast Sensitivity Testing

Contact Info

Product

Resources

About