EST: CL VS SPECS

Question 1

what causes an adaptation period to be required after switching from specs to CL?

Answer 1

Prismatic Effect & Vergence with Contact Lenses

Change in accommodation demand

Question 2

explain Prismatic Effect & Vergence with Contact Lenses

Answer 2

Minus spectacle lens, upon convergence in near gaze–> Base-in effect

myopic CL wearer will have to converge more to see a near object than he would have to, when wearing spectacles

plus spectacle lens, upon convergence in near gaze–> Base-out effect

hyperopic CL wearer will have to converge less to see a near object than he would have to, when wearing spectacles

Question 3

explain the Change in accommodation demand when changing from specs to CL

Answer 3

A myope need to accommodate MORE for near tasks than with spectacles

A hyperope need to accommodate LESS for near task than with spectacles

Question 4

explain the change in retinal image size when changing from specs to CL

Answer 4

myope: retinal image size no longer minified, magnifying effect

opposite for hyperope