Comparison of Snellen and Early Treatment Diabetic Retinopathy Study charts using a computer simulation
AIM: To compare accuracy, reproducibility and test duration for the Snellen and the Early Treatment Diabetic Retinopathy Study (ETDRS) charts, two main tools used to measure visual acuity (VA). METHODS: A computer simulation was programmed to run multiple virtual patients, each with a unique set of...
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| Format: | Article |
| Language: | English |
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Press of International Journal of Ophthalmology (IJO PRESS)
2016-01-01
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| Series: | International Journal of Ophthalmology |
| Subjects: | |
| Online Access: | http://www.ijo.cn/en_publish/2016/1/20160120.pdf |
| _version_ | 1818272312064999424 |
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| author | Reuben R. Shamir Yael Friedman Leo Joskowicz Michael Mimouni Eytan Z. Blumenthal |
| author_facet | Reuben R. Shamir Yael Friedman Leo Joskowicz Michael Mimouni Eytan Z. Blumenthal |
| author_sort | Reuben R. Shamir |
| collection | DOAJ |
| description | AIM: To compare accuracy, reproducibility and test duration for the Snellen and the Early Treatment Diabetic Retinopathy Study (ETDRS) charts, two main tools used to measure visual acuity (VA).
METHODS: A computer simulation was programmed to run multiple virtual patients, each with a unique set of assigned parameters, including VA, false-positive and false-negative error values. For each virtual patient, assigned VA was randomly chosen along a continuous scale spanning the range between 1.0 to 0.0 logMAR units (equivalent to 20/200 to 20/20). Each of 30 000 virtual patients were run ten times on each of the two VA charts.
RESULTS: Average test duration (expressed as the total number of characters presented during the test ±SD) was 12.6±11.1 and 31.2±14.7 characters, for the Snellen and ETDRS, respectively. Accuracy, defined as the absolute difference (± SD) between the assigned VA and the measured VA, expressed in logMAR units, was superior in the ETDRS charts: 0.12±0.14 and 0.08±0.08, for the Snellen and ETDRS charts, respectively. Reproducibility, expressed as test-retest variability, was superior in the ETDRS charts: 0.23±0.17 and 0.11±0.09 logMAR units, for the Snellen and ETDRS charts, respectively.
CONCLUSION: A comparison of true (assigned) VA to measured VA, demonstrated, on average, better accuracy and reproducibility of the ETDRS chart, but at the penalty of significantly longer test duration. These differences were most pronounced in the low VA range. The reproducibility using a simulation approach is in line with reproducibility values found in several clinical studies. |
| first_indexed | 2024-12-12T21:40:04Z |
| format | Article |
| id | doaj.art-22804b1d1a9d4b38b0867523806c62a1 |
| institution | Directory Open Access Journal |
| issn | 2222-3959 2227-4898 |
| language | English |
| last_indexed | 2024-12-12T21:40:04Z |
| publishDate | 2016-01-01 |
| publisher | Press of International Journal of Ophthalmology (IJO PRESS) |
| record_format | Article |
| series | International Journal of Ophthalmology |
| spelling | doaj.art-22804b1d1a9d4b38b0867523806c62a12022-12-22T00:11:04ZengPress of International Journal of Ophthalmology (IJO PRESS)International Journal of Ophthalmology2222-39592227-48982016-01-019111912310.18240/ijo.2016.01.20Comparison of Snellen and Early Treatment Diabetic Retinopathy Study charts using a computer simulationReuben R. Shamir0Yael Friedman1Leo Joskowicz2Michael Mimouni3Eytan Z. Blumenthal4School of Engineering and Computer Science, the Hebrew University, Jerusalem 91120, Israel.Department of Ophthalmology, Hadassah – Hebrew University Medical Center, Jerusalem 91120, Israel.School of Engineering and Computer Science, the Hebrew University, Jerusalem 91120, Israel.Department of Ophthalmology, Rambam Medical Center, Haifa 31096, Israel.Department of Ophthalmology, Rambam Medical Center, Haifa 31096, Israel.AIM: To compare accuracy, reproducibility and test duration for the Snellen and the Early Treatment Diabetic Retinopathy Study (ETDRS) charts, two main tools used to measure visual acuity (VA). METHODS: A computer simulation was programmed to run multiple virtual patients, each with a unique set of assigned parameters, including VA, false-positive and false-negative error values. For each virtual patient, assigned VA was randomly chosen along a continuous scale spanning the range between 1.0 to 0.0 logMAR units (equivalent to 20/200 to 20/20). Each of 30 000 virtual patients were run ten times on each of the two VA charts. RESULTS: Average test duration (expressed as the total number of characters presented during the test ±SD) was 12.6±11.1 and 31.2±14.7 characters, for the Snellen and ETDRS, respectively. Accuracy, defined as the absolute difference (± SD) between the assigned VA and the measured VA, expressed in logMAR units, was superior in the ETDRS charts: 0.12±0.14 and 0.08±0.08, for the Snellen and ETDRS charts, respectively. Reproducibility, expressed as test-retest variability, was superior in the ETDRS charts: 0.23±0.17 and 0.11±0.09 logMAR units, for the Snellen and ETDRS charts, respectively. CONCLUSION: A comparison of true (assigned) VA to measured VA, demonstrated, on average, better accuracy and reproducibility of the ETDRS chart, but at the penalty of significantly longer test duration. These differences were most pronounced in the low VA range. The reproducibility using a simulation approach is in line with reproducibility values found in several clinical studies.http://www.ijo.cn/en_publish/2016/1/20160120.pdfEarly Treatment Diabetic Retinopathy StudySnellencomputer simulationvisual acuity testingvirtual patients |
| spellingShingle | Reuben R. Shamir Yael Friedman Leo Joskowicz Michael Mimouni Eytan Z. Blumenthal Comparison of Snellen and Early Treatment Diabetic Retinopathy Study charts using a computer simulation International Journal of Ophthalmology Early Treatment Diabetic Retinopathy Study Snellen computer simulation visual acuity testing virtual patients |
| title | Comparison of Snellen and Early Treatment Diabetic Retinopathy Study charts using a computer simulation |
| title_full | Comparison of Snellen and Early Treatment Diabetic Retinopathy Study charts using a computer simulation |
| title_fullStr | Comparison of Snellen and Early Treatment Diabetic Retinopathy Study charts using a computer simulation |
| title_full_unstemmed | Comparison of Snellen and Early Treatment Diabetic Retinopathy Study charts using a computer simulation |
| title_short | Comparison of Snellen and Early Treatment Diabetic Retinopathy Study charts using a computer simulation |
| title_sort | comparison of snellen and early treatment diabetic retinopathy study charts using a computer simulation |
| topic | Early Treatment Diabetic Retinopathy Study Snellen computer simulation visual acuity testing virtual patients |
| url | http://www.ijo.cn/en_publish/2016/1/20160120.pdf |
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