andlt;strongandgt;Snellen eye test chart.andlt;/strongandgt; Blurred view of aSnellen eye test chart used for measuring visualacuity. A patient stands a set distance (usuallysix metres) from the chart, and covers one eyebefore reading as far down the chart as they can.The letters decrease in size lower down the chart.If they are unable to read a sufficient amount ofthe chart, lenses of different strengths are useduntil their vision is sharp enough to allowrecognition of the smallest letters. Inconjunction with other visual tests, this testallows the diagnosis of eye disorders such aslong- and shortsightedness (andlt;emandgt;hypermetropiaandlt;/emandgt; andandlt;emandgt;myopiaandlt;/emandgt;). These disorders can be corrected withspectacles or contact lenses.
