Clinical Optometry I Midterm II

The temporal limbus

When performing the Interpupillary Distance (IPD) test, where do you align the zero point of the ruler at in relation to the patient's left eye?

40 cm (typical working distance)

How far away should you be when viewing the ruler when performing IPD?

left eye; near pupillary distance (PD)

When performing an IPD measurement, what eye (i.e. your eye) do you use to measure the distance between the temporal limbus of their right eye with the nasal limbus of their left eye? What measurement does this give you?

True

True/False: When measuring the distance PD of a patient, ensure you do not move the ruler and read off the measurement, except now, with your right eye open and your left eye closed

If the examiner and patient has significantly different PDs

In what scenario would you have to "move the ruler" in order to achieve an accurate distance PD?

distance/near (in mm)

How do we record IPD?

1. Accomodation
2. Convergence
3. Miosis (pupillary constriction)

What three things occur as part of the "near triad" reflex whe. we focus on something up close?

vergence

A nonparallel or disjunctive movement of the visual axes

Convergence

When the lines of sight are directed to a point in space closer to the observer than the original point of fixation

near point of convergence (NPC)

A measurement of the maximum amount of convergence that a patient can exert to maintain a single (not necessarily clear) vision of a nearpoint target

6-7 cm

What is the approximate expected value of near point convergence (NPC)?

NPC recovery

The distance at which the patient can regain single vision of the same nearpoint target from the near point of convergence test

12 cm

What is the approximate expected value of NPC recovery?

40 cm; 20 degrees

For NPC, how far away should the patient be viewing a threshold, near-point target binocularly? About how many degrees down should this target be?

False--high illumination

True/False: For proper NPC results, conditions are supposed to be under low light conditions.

When the target becomes double ("but try to keep it single")

In NPC examination, what should you instruct the patient to report as the target is moved towards them?

meter angle

Reciprocal of the distance between the centers of rotation of the eyes and the near-point of convergence (MA=100/(working distance in cm + 27)

diopter; prism diopters

The meter angle is convenient to use because it closely approximates the _____________ unit for accomodation, but when we think of convergence, it is in terms of _____________________.

9.37 prism diopters

What is the convergence demand for a patient with a PD of 40mm (4 cm) who works at a 40 cm distance (from the spectacle plane)?

Convergence demand

--Takes into account the patient's PD in order to accurately measure the total convergence of the eyes
--Meter angle x PD (in cm)

accomodation

"The ability of the eye to focus clearly for objects at various distances" via a change in the crystalline lens

Near point of accommodation (NPA)

The nearest point for which a sharp image point will be formed on the retina of an emmetropic or uncorrected ametropic eye

amplitude of accommodation (AA)

The dioptric value of the NPA of the eye less the dioptric value of the far point of accomodation (clinically, the reciprocal of the NPA)

True

True/False: A patient is generally comfortable using no more than half of their AA for prolonged periods of time.

1. Moving an object closer (Push-up or Doner's method)
2. Putting a minus lens in front of the eye (minus lens method)

What 2 methods can stimulate accommodation?

Hofstetter's formulas

Formulas based on the notion that accommodative ability decreases with advancing age

25--0.40 (age)

What is the maximum expected amplitude Hofstetter's formula?

15--0.25 (age)

What is the minimum expected amplitude Hofstetter's formula?

18.5--0.30 (age)

What is the average expected amplitude Hofstetter's formula?

binocularly & monocularly

With NPA testing, the examination is done (binocularly/monocularly/binocularly & monocularly).

high illumination

NPA testing is to be down in (low illumination/high illumination) conditions.

40 cm away; 20 degrees down

How far away is the examiner supposed to hold threshold size near letters away from the patient? How many degrees down?

When they notice their "first sustained blur"

For NPA testing, what should you ask the patient to report as you move the near-point letters toward them?

AA=100/NPA (in cm) or 1/NPA (in m)

What formula do you use to convert NPA to AA?

Centered between their eyes at 40 cm away, 20 degrees down

With NPA testing done binocularly, where do you place the nearpoint target in relation to the patient?

subtract

For a presbyopic patient, after you determine their AA, you must ___________ their dioptric value of their reading add to get their true, unaided AA.

To test the responsiveness of the pupil to near viewing

What is the purpose of the near pupillary response exam?

False

True/False: The task lamp is not needed for the pupillary response procedure.

wear

For pupillary response testing, the patient is to (not wear/wear) his or her distance correction.

20

In the pupillary response procedure, instruct the patient to look at a letter on the distance acuity chart, which is _________ feet away.

Letter on the line of best acuity or above the best acuity level

For the pupillary response procedure, what size should the letter on the distance acuity chart be?

The patient's pupil

What should you ensure you are looking at while the patient is looking back and forth between the near target and the distance acuity chart?

25 cm

In the pupillary response procedure, how far away should the near target be from the patient?

Whether the pupils constrict and the rate of pupil constriction

What should you be assessing during the pupillary response procedure?

1. Blocking the patient's view of the visual acuity chart and stimulating accommodation and subsequent pupil constriction
2. Forgetting to check pupil reflexes prior to instilling a mydriatic or cycloplegic drop

What are the 2 most common errors of the pupillary response procedure?

1. Ductions
2. Versions (aka EOMs)
3. Saccades
4. Smooth pursuits

What are the 4 testing procedures of ocular motility?

Duction

Movement of the eye by the extraocular muscles under monocular conditions

Coordinated relaxation & contraction of the six EOMs and occur in synchrony with movements of the other eye

Under normal physiological conditions, what causes duction movements?

adduction

One eye turns in toward the nose

abduction

One eye turns out away from the nose

Supraduction

The eye turns up

infraduction

The eye turns down

Encycloduction

The top of the vertical axis of the cornea turns in

Excycloduction

The top of the vertical axis of the cornea turns out

Only after versions if results were abnormal

In what situation would you perform ductions?

not wear

For duction testing, the patient should (not wear/wear) correction.

moderate

During ductions, the room illlumination should be (low/moderate/high).

Penlight or transilluminator

What is the main instrument you use to conduct ductions?

monocular

Ductions are performed in (monocular/binocular) conditions

40

During ductions, the target should be presented to the patient directly in front of the patient's non-occluded eye at about _____ cm away.

Follow the target with your eyes as I move it and tell me if you have any pain

What should you instruct the patient to do for duction testing?

1. Double H method
2. Single H method

What 2 methods can be used to conduct duction testing?

1. Restriction in gaze
2. Jerkiness or nystagmus
3. Over- or under- actions

What are the three things you are observing with the patient's eye movements during duction testing?

70 degrees inferior, 50 degrees superior, 50 degrees laterally

What are the normal limits of motion using the H method for duction testing?

Deep seated neurological problem involving one or more of the muscles or their neurological connections

An inability to follow a target or restrictriction may indicate what?

1. FROM
2. SAFE

What are the 2 ways to record "normal" duction results?

Full range of motion

What does the result, FROM, stand for in duction testing?

Smooth, accurate, full, extensive

What does the result SAFE stand for in duction testing?

Which eye is affected and which direction is restricted

If you happen to find any restrictions during duction testing, what information should you include in your result work-up?

Which eye, which direction OR smooth and accurate (if normal)

If you encounter jerkiness or a nystagmus during duction testing, what information should you include in your result work-up?

Which eye & which direction

If you encounter over-actions or under-actions during duction testing, what information should you include in your result work-up?

amblyopic; amblyopic

A/an ___________________ eye will often have poorer 0erformance than the non-______________ eye during duction testing (won't follow target accurately or may be sluggish).

Nine diagnostic positions of gaze method

Duction target movement pattern with nine different positions that can be conceptualized as the 9 squares on a tic-tac-toe game with the center square corresponding to the straight ahead or "primary position"

1. The "H" or double plus method
2. Nine diagnostic positions of gaze method

What are the 2 target movement patterns for duction testing?

The "H" or double plus method

--Duction target movement pattern that attempts to test each of the 6 EOMs independently by forcing the eye to move into the position of primary action for each muscle

superior rectus

During duction testing using the double plus method, to test the _____________________ muscle, the target should be positioned 23 degrees temporal to the primary position and moved upward.

Superior oblique (SO) and Inferior oblique (IO)

During duction testing using the double plus method, to test the __________________ & _________________ muscles, the target should be moved downward and upward respectively from a starting position 51 degrees nasal to the primary position.

Versions

--Binocular eye movement in which the angle between the lines of signt of the two eyes does NOT change; conjugate movements
--Occur when we want to look from one point in space to another point that is the same distance away

1. Dextroversion
2. Levoversion
3. Supraversion
4. Infraversion
5. Dextrocycloversion
6. Levocycloversion

What are the 6 classifications of versions?

Dextroversion

Eyes move to the patient's right (version classification)

Levoversion

Eyes move to patient's left (version classification)

Supraversion

Both eyes move up (version classification)

Infraversion

Both eyes move down (version classification)

Dextrocycloversion

The tops of both vertical axes of the corneas rotate to the right (version classification)

Levocycloversion

The tops of both vertical axes of the corneas rotate to the left (version classification)

version; midline

The same techniques and method of recording are used for __________ testing that were described in duction testing except that no occluder is used and we start at the ___________.

1. Restriction of movement
2. Jerkiness or nystagmus
3. Noncomitance
4. Over-actions or under-actions of one or both eyes

What are the 4 things you should be evaluating as an examiner during version testing?

Noncomitance

Classification of one eye lagging behind the other in a certain field of gaze

Paralysis or paresis of one or more EOMs

Noncomitance would indicate what during version testing?

double

If noncomitance is observed during version testing, often times, the patient will report seeing __________________ in that direction.

True

True/False: If a restrictions exists in one eye, this will always be manifested in both monocular (duction) and binocular (version) testing.

binocularly

Sometimes in strabismus patients, certain types of strabismus will only show an irregularity in motility patterns if tested ________________.

saccades

Eye movement in which the eyes abruptly change fixation from one point in space to another; conjugate movements of the eye (no change in vergence occurs)

Parkinson's disease, OM nerve paresis, cerebellar disease, problems with systemic medications exist

Abnormal saccades exist with what neurological conditions?

wear

With NPC, the patient should (not wear/wear) near correction.

Two targets--pencils with colored tips or pins in erasers

What equipment is needed for saccade testing?

40 cm

How far apart should you hold the targets from the patient in saccade testing?

monocular & binocular

Saccade testing is done in (monocular/binocular/monocular & binocular) conditions.

Horizontal, vertical, oblique

Saccade testing should be tested in what meridians?

1. Accuracy
2. Overshooting or undershooting
3. Number of refixations
4. Any head or body movement involved

What 4 anomalies should the examiner be looking for while performing saccades?