Can anyone explain the simple way of understanding how to determine the effective powers at any meridian and a cylinder power. I DO NOT KNOW THE STEPS IF THERE IS. I am taking the ABO Exam this May 20,2012. GOD HELP ME!

I WAS WONDERING HOW COME ON NUMBER 9 THE ANSWER IS 0%?
IF YOU DO THE PROBLEM…90TH MERIDIAN-45 SPECIFIED AXIS IS 45…AND 45 DEGREES IN A KEY PERCENTAGE CONVERTS TO 50% OF THE CYLINDER POWER…WOULDN’T 50% BE THE ANSWER? NO 0%? IF IT IS 0%..I JUST WANTED TO MAKE SURE WHY…I HAVE THE TEST IN 2 WEEKS AND IT WOULD BE VERY HELPFUL THANK YOU

This one got me too. The wording is kind of tricky. I thought that when they said “specified axis” they meant the one they were asking about in the previous question, i.e. the 90th meridian. But what the question actually refers to is the axis specified by the RX, i.e. the 45th meridian. Tricky one.

There are 2 questions listed regarding cylinder power. The 1st question asks about cylinder power at the specified axis with the answer – 100%. The 2nd question asks the cylinder power at 90 degrees away from the specified axis with the answer – 100%. Which is correct?

Question #5 is incomplete.

What is the best base curve for a +2.50D lens?

Shouldn’t that be 8.5 not 8? If you add 6 to the sphere power.

+2.50/2 + 6.00 = 7.25 (8.00 is the closes)

Can anyone explain the simple way of understanding how to determine the effective powers at any meridian and a cylinder power. I DO NOT KNOW THE STEPS IF THERE IS. I am taking the ABO Exam this May 20,2012. GOD HELP ME!

Take a look here: http://www.laramyk.com/resources/education/lens-form-and-theory/lens-form-sphere-cylinder-and-axis/

Q5 is incompleate… the q is The reason for using a “best form” lens is to minimize _________.

Thanks Lisa! It’s now fixed.

To k13, if you do cross cilinder you get (-1.00 x 180) (-2.50 x 90). Why is the answer -2.50?

I WAS WONDERING HOW COME ON NUMBER 9 THE ANSWER IS 0%?

IF YOU DO THE PROBLEM…90TH MERIDIAN-45 SPECIFIED AXIS IS 45…AND 45 DEGREES IN A KEY PERCENTAGE CONVERTS TO 50% OF THE CYLINDER POWER…WOULDN’T 50% BE THE ANSWER? NO 0%? IF IT IS 0%..I JUST WANTED TO MAKE SURE WHY…I HAVE THE TEST IN 2 WEEKS AND IT WOULD BE VERY HELPFUL THANK YOU

This one got me too. The wording is kind of tricky. I thought that when they said “specified axis” they meant the one they were asking about in the previous question, i.e. the 90th meridian. But what the question actually refers to is the axis specified by the RX, i.e. the 45th meridian. Tricky one.

There are 2 questions listed regarding cylinder power. The 1st question asks about cylinder power at the specified axis with the answer – 100%. The 2nd question asks the cylinder power at 90 degrees away from the specified axis with the answer – 100%. Which is correct?