Visual aquity and contrast sensitivityVishy SrivastavaThis document provides a summary of a presentation on visual acuity and contrast sensitivity. It discusses:
1. Visual acuity testing methods including Snellen charts, LogMAR charts, and methods for testing children.
2. Contrast sensitivity testing methods including Pelli-Robson charts and Cambridge Low Contrast gradings.
3. The importance of contrast sensitivity over visual acuity for assessing daily visual function, as visual acuity does not account for low contrast situations.
Contrast sensitivityJagdish DukreContrast sensitivity refers to the ability to see objects that have low contrasts or do not stand out clearly from their backgrounds. It is measured using charts with different spatial frequencies and contrast levels to determine the minimum contrast needed to see a target. Contrast sensitivity is affected by many eye diseases and conditions more subtly than visual acuity and can provide early detection of problems. It is tested using various charts like Pelli-Robson, Cambridge Low Contrast Gratings, and Functional Acuity Contrast Testing (FACT) that evaluate contrast sensitivity levels at different spatial frequencies.
modulation transfer function (MTF)AJAL A JThe resolution and performance of an optical microscope can be characterized by a quantity known as the modulation transfer function (MTF), which is a measurement of the microscope's ability to transfer contrast from the specimen to the intermediate image plane at a specific resolution.
Color Vision TestingRyan AlfonsoThe document discusses color vision testing techniques and color deficiencies. It describes various color vision tests including pseudoisochromatic plates, lantern tests, arrangement tests, and anomaloscopes. It explains what each test screens for and its purpose. It also discusses the different types of color deficiencies including red, green, blue deficiencies and how color may appear to those with deficiencies.
Colour visionJagdish DukreColour vision allows for the discrimination of different colours that are excited by different wavelengths of light. Colour vision is mediated by cone cells and functions best in bright light, while in dim light all colours appear grey. There are three properties that specify colour - hue determined by wavelength, saturation describing colour intensity, and brightness indicating light intensity. The distribution of colour vision in the retina ranges from blue-blind in the very centre to monochromatic vision in the far periphery. Two main theories describe the mechanisms of colour vision - the trichromatic theory involving three cone types sensitive to red, green and blue, and the opponent colour theory where red-green and blue-yellow opponent cells code colour contrasts. Both theories are useful, with tr
TQM & Operations Management for SustainabilitySajee SirikraiLesson learned from Operations Management Seminar at Thammasat Business School in Cooperation with CONC and FTQM
TQM & Operations Management for SustainabilitySajee SirikraiLesson learned from Operations Management Seminar at Thammasat Business School in Cooperation with CONC and FTQM