Astigmatism/Presbyopia - Diagnosis and Management of Common Ocular Conditions Spring 2026

When is correcting astigmatism in glasses a problem?

If there is significant meridian by meridian anisometropia present

Is correcting WTR astigmatism easy?

yes

What is an example of with the rule astigmatism?

OD: -1.50-2.50x180

OS: 01.50-2.50x180

Is correcting astigmatism in one eye (monocular) easy?

No -- this is difficult d/t image size differences

What is an example of a prescription with astigmatism correction in one eye?

OD: -1.50DS

OS: -1.50-2.50x180

Is correcting astigmatism obliquely easy?

No -- this is VERY DIFFICULT

What is an example of a prescription that has astigmatism correction in an oblique meridian OU?

OD: -1.50-2.50x110

OS: -1.50-2.50x070

What are the symptoms associated with uncorrected astigmatism?

-blur

-HA

-strain

What are some issues associated with correcting for astigmatism in specs?

-issues with prismatic effects when looking away from the optical center

-aniseikonia (differing image sizes in either eye)

What is the best plan in order to correct astigmatism?

contact lenses (for the same reasons as anisometropia)

If astigmatism is fully corrected in specs, is this guaranteed to cause the patient problems?

no -- it may not cause any problems

If you are going to fully correct a patient's astigmatism in glasses, what should you do?

demonstate the rx in a trial frame and have the patient WALK AROUND

If the full glasses correction is not accepted in a trial frame, what are the next options for the patient to correct their astigmatic prescription?

-eikonic lens design

-modify the prescription for the patient

Is partial correction for astigmatism a valid way to modify the rx of a patient who is symptomatic in full astigmatic correction?

Yes

What do you need to maintain if you reduce the cyl power for an astigmatic patient?

Need to make sure you maintain the spherical equivalent

You can rotate the cyl axis toward _____ or _____ if the cyl is already close to one of these meridians in order to reduce astigmatic correction symptoms

180, 90

If only partially correction a patient's astigmatism, can we try to increase their Rx over time?

Yes

Example Problem

OD: +1.00-3.00x175

OS: pl-0.50x005

The full rx is NOT accepted, you decide to cut 1D cyl. Which eye should you cut the cyl from?

OD

Example Problem

OD: +1.00-3.00x175

OS: pl-0.50x005

You decide to cut 1D of cyl from OD. What is the final rx you will prescribe?

-OD SE: -0.50

-OD Final RX: +0.50-2.00x175

-OS Final RX: pl-0.50x005

Example Problem

OD: +1.00-3.00x180

OS: +1.00-3.00x180

OD: pl-0.75x045

OS: pl-0/75x135

Which of these prescriptions will most likely cause symptoms for the patient?

OD: pl-0.75x045

OS: pl-0/75x135

***Oblique axis = likely to be symptomatic

What are the signs/symptoms of presbyopia?

-reduced VA at near

-blur at near, typically worse under reduced illumination

-blur is worse when fatigued or ill

-increased light needed at near

With early presbyopia, can the patient have good near VA?

Yes -- but the patient may complain of tired eyes or become sleepy after near work

Tests to Consider for the Clinical Determination of an Appropriate Near Add?

-age expected ADD

-dynamic retinoscopy

-amplitude of accommodation

-binocular cross cylinder

-NRA/PRA

What are the WORST tests for determining ADD as established by the "Determining Adds in Presbyopia" Study?

-dynamic retinoscopy

-amplitudes of accommodation

What are the BEST tests for determining ADD as established by the "Determining Adds in Presbyopia" Study?

-age expected

-others were within an acceptable range

What is the formula for an Age-Based Tentative Add?

+0.75+(0.1 for every year over 40)

**This will be rounded to the nearest +0.25

What is the BEST way to gauge acceptance of an ADD power?

demoing the add -- NOT in the phoropter

How are you able to demonstrate an ADD outside of the phoropter?

-Can use trial frames or flippers

-Demo over current glasses if no large change in distance RX

What is the effective ADD?

The actual near addition that a patient is receiving with an RX after factoring in any uncorrected (or under/over corrected) refractive error

What is the effective ADD power in this situation?

A +2.50 Hyperope is wearing +2.00OU ADD +2.00 specs

-This hyperope is +0.50 undercorrected

-+0.50 more accommodation at near than normal

-First +0.50 of the ADD is used to correct the hyperopia

-Effective Add is +1.50

What is the effective ADD power when this patient is wearing their specs?

MR: -2.00

Lenso: -1.50 Add: +1.25

-This myope is -0.50 undercorrected

--0.50 more accommodation at near than normal

-Built in +0.50 add

-Effective Add is +1.75

What is the effective ADD power when this patient is wearing their specs?

MR: -1.00

Lenso: -1.50 Add: +1.25

-This myope is +0.50 overcorrected

-+0.50 more accommodation at near than normal

-First +0.50 of the ADD is used to correct the hyperopia

-Effective Add is +0.75

What is the effective ADD power when this patient is wearing their specs?

Your low vision patient is a -1.00D myope OU and has the best reading performance in +4.00D reading glasses. She is interested in a pair of bifocals. What is the effective ADD?

--1.00 myope has a 1D built in ADD + 4.00D in reading glasses

-Distance RX in bifocals = -1.00

-Near Rx in bifocals (effective add)= +5.00

What rx would you prescribe?

Lenso: -1.50sph ADD: +1.25

MR: -1.50-0.50x180

Using your flippers, you demo lenses over the patients current bifocal while he reads and he prefers the +0.50 lenses.

-SE MR: -1.75

-Patient is a -0.25 undercorrected myope

-Patient will have a +0.25 built in add

-Effective Add = +1.50

-Effective Add = +0.50 flippers over +1.50 = +2.00

What is the effective ADD?

MR: -4.00D OU

With no correction in place, you demo Rx with flippers and the patient prefers -2.00D.

Effective Add = +2.00

What is the prescription you would give for a single vision reading Rx?

MR: -4.00D OU

With no correction in place, you demo Rx with flippers and the patient prefers -2.00D.

-2.00

What is the prescription you would give for a bifocal?

MR: -4.00D OU

With no correction in place, you demo Rx with flippers and the patient prefers -2.00D.

-4.00 w/ +2.00 ADD