There have been relatively few attempts to represent sight or blindness ontologically. This is unsurprising as the related phenomena of sight and blindness are surprisingly difficult to represent ontologically for a variety of reasons. This paper discusses those reasons, explores the current attempts to represent sight or blindness, and how these attempts fail at representing certain types of b...

In combination with randomization, blinding or masking is an important factor in randomized controlled trials (RCTs), particularly in trials that assess therapeutic effects. Here an attempt is made to explain blindness and why it is important. In clinical trials, blinding is defined as the condition imposed on a study in which study participants, health care providers and assessors collecting o...

purpose: to estimate the magnitude and causes of visual impairment (vi) in subjects aged ≥ 50 years in varamin district in 2009 using the proposed method by the world health organization (who). method: this cross sectional population based survey was performed in varamin targeting people over the age of 50 years using the proportional probabilities to size and cluster compact segment sampling m...