Optometry final exam Answered Questions | Already Passed | 100 % Correct Answers

emmetropia Ans: optical state of the eye in which parallel light enters the eye and focuses on the retina without the need for any corrective lenses or accommodation; this is the absence of refractive error and the "normal" or ideal state of the eye ametropia Ans: refractive error, "abnormal" optical state of the eye in which parallel light rays enter the eye and focus on an area other than the retina; this condition requires corrective lenses to produce clear retinal images astigmatism Ans: optical error in which refractive power is not uniform in all meridians; light entering the eye is focused at two distinct focal points where at least one focal point does not fall onto the retina How can corneal astigmatism be measured? Ans: keratometry What are components of sphere-cylinder lens RX? Ans: 1. Power (magnitude in D) of sphere component 2. Power (magnitude of D) of cylinder component 3. Axis (orientation) of the cylinder i.e. +2.00 -3.00 X 145 i.e. -5.00 -2.00 X 060 If one meridian is at 60 degrees, where is the other Ans: 150 degrees because 60+90=150 What are the possible values for magnitude of axis? Ans: 1 degree-180 degrees How can one determine the powers of the 2 principal meridians? Ans: Principal meridian 1=power of more (+) meridian Principal meridian 2=sum of sphere and cylinder componenets Find primary and secondary meridians for this Rx. +1.00 -2.00 X 110 Ans: Principal meridian 1=+1.00D Principal meridian 2=+1.00D + -2.00D= -1.00D Find the primary and secondary meridians for the Rx. -3.00 -4.50 X 010 Ans: Principal meridian 1= -3.00D Principal meridian 2= -3.00D + -4.50D= -7