Optometry Final E xam Questions with Answers How does this add change based on the patient's working distance? - Answer -The closer the w orking distance, the higher the add must be to make the target clear. Describe accommodation - Answer -Increase in optical power (plus power) of lens to maintain clear retinal image of object that is clo ser than optical infinity; this occurs through contraction and relaxation of ciliary muscles of eye, which attach to suspensory ligaments (zonules of Zinn) which changes the shape and power of the lens. What kind of light rays are produced if the target i s at optical infinity? and closer than optical infinity? - Answer -at optical infinity -targets produce parallel light rays; if the target is closer than optical infinity, divergent rays are produced and require a plus (convergent) lens or increased accommod ation to see it clearly. Describe accommodation when the lens is in its resting state - Answer -The resting state is adjusted for distance viewing. The ciliary muscle is relaxed, pulled back which puts tension on zonules, causes lens to have thinner, less convex profile and so less plus power Describe accommodation when lens is in its accommodative state - Answer -the accommodative state is adjusted for near viewing. The ciliary muscle is contracted, bulges forward which releases tension on zonules, causes lens to have a thicker, more convex profile and so more plus power Which is more correct when referring to patient's refractive error? a. 3.00D myope b. -3.00D myope - Answer -b -3.00D myope Always refer to pt's refractive error in terms of lens required to correct it Is it necessary to include a sign indicating whether a power is plus or minus? - Answer -
YES What does plano reflect? and What is an accepted abbreviation? - Answer -PL indicates zero sphere power What does sph or DS indicate? - Answer -Sphere and diopter sphere are ways of indicating no cyclindrical componenet ie. +3.00 sph or +3.00 Ds never +3.00 How many digits should be written in each part of Rx? - Answer -Sphere and cylinder powers to the second decimal point. Axis with three digits, no decimal points. Do we use plus cylinder form? - Answer -No, ophthalmologists however do. What can this Rx be correcting? -1.00 Ds - Answer -simple myopia What can this Rx be correcting? +5.25 -5.25 X 095 - Answer -simple hyperopic astigmatism What can this Rx be correcting? -2.50 -0.50 X 095 - Answer -compound myopic astigmatism What can this Rx be correcting? +3.00 -3.50 X 170 - Answer -mixed astigmatism What are the 8 different types of refractive error? - Answer -7 distance refractive errors which assume that accommodation is at rest and that the eye is looking at a distant target (optical infinity) 1 near ref ractive error that involves a target closer than optical infinity and may involve accommodation Define diopter - Answer -unit of measurement of the refractive power of the lens, and is equal to the reciprocal of the focal length as measured in meters What is the focal point of a +2.00D lens? - Answer -0.5 m or 50 cm What is the dioptric power of a lens that has a focal point of 20 cm? - Answer -+5.00 D Define spherical refractive error - Answer -Refractive error is uniform in all meridians. No matter where cross -section is taken, the refractive error is the same magnitude throughout Define hyperopia - Answer -parallel light entering the eye is focused behind the retina and requires a plus lens to converge the light to properly focus it on the retina; eye has too much minus power Define myopia - Answer -parallel light entering the eye is focused in front of the retina and requires a minus lens to diverg the light to properly focus it on the retina; eye has too much plus power What kind of lens is necessary to correct for astigmatism? - Answer -the two focal lengths need a lens with 2 different powers to bring the light to one single focal point on the retina; a sphere -o-cylinder lens (compound lens or sphere -cylinder lens) has one
YES What does plano reflect? and What is an accepted abbreviation? - Answer -PL indicates zero sphere power What does sph or DS indicate? - Answer -Sphere and diopter sphere are ways of indicating no cyclindrical componenet ie. +3.00 sph or +3.00 Ds never +3.00 How many digits should be written in each part of Rx? - Answer -Sphere and cylinder powers to the second decimal point. Axis with three digits, no decimal points. Do we use plus cylinder form? - Answer -No, ophthalmologists however do. What can this Rx be correcting? -1.00 Ds - Answer -simple myopia What can this Rx be correcting? +5.25 -5.25 X 095 - Answer -simple hyperopic astigmatism What can this Rx be correcting? -2.50 -0.50 X 095 - Answer -compound myopic astigmatism What can this Rx be correcting? +3.00 -3.50 X 170 - Answer -mixed astigmatism What are the 8 different types of refractive error? - Answer -7 distance refractive errors which assume that accommodation is at rest and that the eye is looking at a distant target (optical infinity) 1 near ref ractive error that involves a target closer than optical infinity and may involve accommodation Define diopter - Answer -unit of measurement of the refractive power of the lens, and is equal to the reciprocal of the focal length as measured in meters What is the focal point of a +2.00D lens? - Answer -0.5 m or 50 cm What is the dioptric power of a lens that has a focal point of 20 cm? - Answer -+5.00 D Define spherical refractive error - Answer -Refractive error is uniform in all meridians. No matter where cross -section is taken, the refractive error is the same magnitude throughout Define hyperopia - Answer -parallel light entering the eye is focused behind the retina and requires a plus lens to converge the light to properly focus it on the retina; eye has too much minus power Define myopia - Answer -parallel light entering the eye is focused in front of the retina and requires a minus lens to diverg the light to properly focus it on the retina; eye has too much plus power What kind of lens is necessary to correct for astigmatism? - Answer -the two focal lengths need a lens with 2 different powers to bring the light to one single focal point on the retina; a sphere -o-cylinder lens (compound lens or sphere -cylinder lens) has one
