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The chart was designed by Ian Bailey [5] and Jan E. Lovie-Kitchin at the National Vision Research Institute of Australia. [1] [3] They described their motivation for designing the LogMAR chart as follows: "We have designed a series of near vision charts in which the typeface, size progression, size range, number of words per row and spacings were chosen in an endeavour to achieve a ...
Diabetic retinopathy (also known as diabetic eye disease) is a medical condition in which damage occurs to the retina due to diabetes.It is a leading cause of blindness in developed countries and one of the lead causes of sight loss in the world, even though there are many new therapies and improved treatments for helping people live with diabetes.
Intraretinal microvascular abnormalities (IRMA) are abnormalities of the blood vessels that supply the retina of the eye, a sign of diabetic retinopathy. [1] IRMA can be difficult to distinguish from and is likely a precursor to retinal neovascularization. One way to distinguish IRMA from retinal neovascularization is to perform fluorescein ...
For 6/6 = 1.0 acuity, the size of a letter on the Snellen chart or Landolt C chart is a visual angle of 5 arc minutes (1 arc min = 1/60 of a degree), which is a 43 point font at 20 feet. [10] By the design of a typical optotype (like a Snellen E or a Landolt C), the critical gap that needs to be resolved is 1/5 this value, i.e., 1 arc min.
Red free fundus photography utilizes a filter in order to better observe superficial lesions and some vascular abnormalities within the retina and surrounding tissue. A green filter ~540–570 nm is used to block out red wavelengths of light.
Epiretinal membrane or macular pucker is a disease of the eye in response to changes in the vitreous humor or more rarely, diabetes.Sometimes, as a result of immune system response to protect the retina, cells converge in the macular area as the vitreous ages and pulls away in posterior vitreous detachment (PVD).
There is an association between the grade of retinopathy and mortality. In a classic study in 1939 Keith and colleagues [6] described the prognosis of people with differing severity of retinopathy. They showed 70% of those with grade 1 retinopathy were alive after 3 years whereas only 6% of those with grade 4 survived.
PVR is graded as Grade A, B, or C by the Silicone Oil Study and as Grade A, B, C, or D by the Retina Society Terminology Committee. [10] Grade A is characterized by the appearance of vitreous haze and RPE cells in the vitreous. Grade B is characterized by wrinkling of the edges of the retinal tear or the inner retinal surface.