Fluid filled vesicles (20-50µm). Almost circular, intra-epithelial inclusions that show unreversed illumination indicating a lower refractive index than the surrounding tissue.
A measure of how well a person is able to distinguish detail at a specified distance. Testing involves a patient reading high contrast letters off a standardized chart at 6 meters until they can no longer distinguish letters. The standard visual acuity score for a healthy human eye is 6/6, where it is able to resolve detail of at least 1 arc minute. Various factors can influence visual acuity performance during testing, such as tear film disturbances and contact lens deposits.