Methods to Measure Contrast Vision
Conditions
Keywords
Contrast Sensitivity, Diagnostic Techniques, Ophthalmological
Brief summary
This study evaluates the relative performance of different methods to measure the human spectral contrast sensitivity function (CSF).
Detailed description
The human spectral contrast sensitivity function (CSF) is a better way to estimate human vision than letter charts commonly used by ophthalmologists, optometrists and opticians. The current methods used to measure the CSF are often unreliable, due to high variability between measurements. This study will compare four (4) new tests with two (2) currently used standard tests. The contrast sensitivity function will be measured using all of the six (6) methods three times (3) in each of the two (2) eyes at two (2) occasions. Each subjects CSF will be measured 6x3x2x2 = 72 times. In addition, for each of the CSF measurements, the time used to measure the CSF and number of background variables for the subjects will be recorded. After informed consent is obtained, the subjects will undergo a visual examination. If they match the inclusion criteria they will be included. At that time or at their earliest possible convenience, their CSF will be measured using the six methods and some background information will be recorded. The follow-up measurement occasion will occur between 4 to 6 weeks (28 to 42 days) after the first. To facilitate comparison with previous studies, the CSF-measurements (in rel. contrast/cycles/degree) will be converted to a log (Base 10 logarithm) scale. The unit will thus be log CSF (LCSF) \[log\[relative contrast\]/log\[cycles/per degree\]\].
Interventions
DEVICEUCST-V1
A previously developed device, Uppsala Contrast Sensitivity Tester - UCST-V1, that quickly measures the human CSF in one stimulus.
DEVICEUCST-V2
A refined version of the UCST-V1 that randomizes frequency order.
DEVICEUCST-V3
A version that utilises eye-tracking technology to make the measurements more accurate.
DEVICEQuick-CSF (QCSF)
A fast contrast sensitivity measurement method using a Bayesian algorithm.
DEVICEPelli-Robson
A standard method developed using a Sloan-letter chart with decreasing contrast.
DEVICEOptec 6500
A standard test using sinusoidal gratings to measure the contrast sensitivity function.
Sponsors
Uppsala University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
DIAGNOSTIC
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Normal best corrected visual acuity: LogMAR = 0 * No current or previous eye disease in either eye. * Student at Uppsala University
Exclusion criteria
* Previous surgery in any eye * Inability to follow the test procedure.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Average time (in seconds) used to measure the contrast sensitivity function for one eye for each method | At end of data collection (up to 12 months after first subject is included) | — |
| Average area under the curve for the log contrast sensitivity function (AULCSF) in one eye for each method | At end of data collection (up to 12 months after first subject is included) | The area-under-curve of the LCSF, calculated from the measured CSF. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Sources of variability of the average time used to measure the contrast sensitivity function [seconds squared] | At end of data collection (up to 12 months after first subject is included) | The factors occasion, eye, acuity, measurement order, sex,examiner will used in an ANOVA |
| Sources of variability of the average area under the curve for the log contrast sensitivity function [AULCSF squared] | At end of data collection (up to 12 months after first subject is included) | The factors occasion, eye, acuity, measurement order, sex,examiner will used in an ANOVA |
Countries
Sweden
Contacts
Primary ContactLars Malmqvist, M.D
Backup ContactGunneli Ekberg
Outcome results
None listed