Dilation Protocol Flashcards by Carrie Stoelting

KEY: What is the purpose of a dilated fundus exam?

Improve visualization of the fundus
When viewing the fundus is improved, you increase the detection rate of abnormalities
The AOA 2015 evidence based clinical practice guideline states that PHARMACOLOGICAL DILATION is generally required for a thorough evaluation of ocular structures.

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KEY: What are the 6 indications for a dilated fundus exam?

Routine exam for ALL patients
For patients between the ages of 18-39 every 2 years
Patients 65 years and older should have an eye exam ANNUALLY IN THE ABSENCE of a diagnosed ocular condition.
Frequent monitoring with dilation is indicated in a patient with a previous diagnosis of ocular pathology
Patients who are at higher risk of intraocular disease (Diabetic, high myopic)
Patients with symptoms or signs indicative of intraocular disease (Flashing lights, floaters, reduced VAs)

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KEY: What are contraindications and precautions?

Sensitivities to pharmacologic agents
Narrow anterior chamber angle
Presence of iris-fixed intraocular lens (not seen often)
Documentation/Preservation of Pupil Status

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KEY: Contraindications and Precautions

What are pharmacologic agents that people might be sensitive to?

Phenylephrine (adrenergic supersensitivity)
Cyclopentolate: spastic paralysis and brain damage

SENSITIVITY TO PRESERVATIVE

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KEY: Contraindications and Precautions

There is a risk to dilate a patient with a narrow anterior chamber angle. What do you do?

Consider prophylactic peripheral laser iridotomy prior to a dilated fundus exam (DFE) if the angle appears susceptible to closure on gonioscopy.

Note: prophylactic means “to prevent disease”
iridotomy means “incision to the iris”

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KEY: Contraindications and Precautions

If there is the presence of iris-fixed intraocular lens, then there is a risk to do a DFE. What might happen?

There is a risk of IOL dislocation with pupil dilation.

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KEY: Contraindications and Precautions

Why is it important to preserve the pupil status before doing a DFE?

Pupile status can be an important vital sign in patients with intracranial disease (coma evaluation).

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KEY: Contraindications and Precautions

You must dilate with care with patients with a recent ______.

head trauma

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KEY:Contraindications and Precautions

Also, unilateral pharmacologic mydriasis may masquerade as a sign of intracranial disease (_______).

Hutchinson’s pupil

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KEY: What is done in a pre-dilation work-up?

Case History
Visual Acuity
Pupil Reflexes
Intraocular Pressure
Anterior Chamber Angle

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KEY: Why do you need to take a patient’s case history before doing a DFE?

If you get a good history, you know what you are looking for. Ex. If a patient has diabetes, look for diabetic changes.

Visually important in guiding the DFE
Aids in what you are looking for during ophthalmoscopy

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KEY: When should you do a VA in association with a DFE?

ALWAYS do a VA BEFORE any procedure for medico-legal reasons.

Plus, it helps detect problems associated with: Refractive error, optical media, the retina, optic nerve, visual pathways. However, there are serious disorders that do not affect VA.

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KEY: Why do you check pupil reflexes before a DFE?

You need to screen for abnormalities prior to dilation.
It is especially important to search for an afferent pupillary defect (APD) in patients with decreased acuity in one eye.

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KEY: Why check intraocular pressure before a DFE?

It serves as a baseline against which post-dilation IOP can be compared.

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KEY: What is a normal range of IOP?

8 to 23 mm Hg

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KEY: The average intraocular pressure is ____.

15.5 mm Hg

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KEY: A difference in pressure readings of more than _____ between the two eyes in considered to be significant.

2 mm

2 mm is normal. So, anything greater than that is abnormal.

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KEY: Diurnal means “a difference between night and day”. So, with IOP what is a normal diurnal variation?

Between 3 to 4 mm Hg

The highest pressure is in the morning.

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Patients with open-angle glaucoma will often experience a mild transient elevation of IOP after dilation with an __________.

anti-cholingeric agent

Note: Anticholinergics are a class of drugs that block the action of the neurotransmitter acetylcholine in the brain.

What are three ways to measure IOPs?

Digital Palpation
Non-Contact Tonometry
Goldman Applanation Tonometry (The GOLD STANDARD for IOP measurement.

KEY: What is digital palpation?

It is the simplest and least expensive technique for achieving an approximate IOP assessment.

It’s used for conditions where tonometry is not possible like in other countries, nursing homes, etc.

What are advantages of digital palpation?

Simplest and least expensive
Instruments not required
Useful when the external tonometry is not possible (like after penetrating keratoplasty or corneal scarring)
Palpation may be the only feasible technique in patients who are unwilling or unable to undergo other methods of IOP measurement

KEY: What are disadvantages of digital palpation?

THE BIGGEST REASON: Digital palpation is the least accurate method of IOP measurement.

Palpation is best avoided in eyes with significant trauma or in certain postoperative conditions.

How do you record digital palpation?

IOP:

OD, OS Normal palpation @ 1:00 pm

OD, OD

Low to palpation
Normal to palpation
High to palpation

PLUS TIME!!!

What is Non-Contact Tonometry (NCT)?

The cornea is applanated by an air pulse, and IOP is measured without direct contact between the eye and the instrument. It is particularly useful when contact techniques are contraindicated, as in the case of a red eye of infectious origin.

What are advantages of NCT?

1. Quick 2. No anesthetic required 3. Can be delegated 4. No epithelial damage 5. Measure through contact lenses It can be done in a pre-testing room.

What are disadvantages of NCT?

1. Cost 2. Large Instrument 3. Less Portable 4. Must be Factory Calibrated 5. Multiple readings necessary (ocular pulse) 6. Most patients are apprehensive

How do you record NCT?

NCT @ 10:30 am OD 15 mmHg OS 15 mmHg

What are the three anterior chamber angle assessments? Note: Angle closure is when aqueous fills in front part of the eye.

Shadow Test Slit Lamp Evaluation Gonioscopy

KEY: A narrow anterior chamber angle ____ the risk of _______.

INCREASES | angle closure glaucoma

What is the Shadow Test?

The Shadow Test is a rough measurement of the angle of the eye. The anterior chamber depth can be estimated with oblique penlight illumination across the surface of the iris.

What is the Slit Lamp Evaluation?

This method is used the most often. It is the Van Herick technique of peripheral anterior chamber depth estimation.

What is Gonioscopy?

Gonioscopy is the GOLD STANDARD for anterior chamber angle evaluation.

KEY: The anterior chamber angle evaluation that is the gross estimation method is the ____.

Shadow Test

KEY: The shadow test is only used when the _____ is not available.

slit lamp

KEY: On what side is the light presented when doing a Shadow Test?

Temporal Side

KEY: The _____ provides a rough estimate of the anterior chamber depth.

shadow test

When testing the anterior chamber angle depth, what test is useful for basic screening where availability of more sophisticated equipment may be limited?

Shadow Test

Patients with ____________ may develop acute angle-closure glaucoma following pupil dilation, with a rapid severe elevation of IOP.

NARROW anterior chamber angles

KEY: * WARN about the ______ of angle-closure glaucoma and instruct the patient to contact you if the symptoms occur, * DOCUMENT the warning and instructions given to the patients.

signs and symptoms

What are the risk factors for Narrow-Angle Glaucoma?

1. AGE--older people; With age, the lens gets larger and that increases the risk for pupil block. Also, the anterior chamber tends to become increasingly shallow and the drainage may narrow as we age. 2. RACE-- Asians and northern indigenous people who have more narrow anterior chamber angles 3. SEX-- 3x more women get it Interestingly, men and women are affected equally among African-Americans

What are causes of Narrow Angle Glaucoma?

1. HYPEROPIA 2. Pupillary Block* 3. Iris Plateau* 4. Tumors and other causes* * will be discussed more in depth in future lectures

Why is Hyperopia a cause of Narrow Angle Glaucoma?

People who are farsighted are more likely to have eyes with SHALLOW anterior chambers and NARROW angles, increasing their risk for angle-closure glaucoma from pupil dilation or aging changes in the eye.

KEY | Signs and Symptoms of Angle Closure Glaucoma include:

1. Severe Eye Pain 2. Blurred vision and/or seeing HALOS around lights 3. Headache 4. Nausea and vomiting 5. Profuse tearing 6. Red Eye 7. Dilated pupils

Ocular Emergency! If not reduced within hours, ________ may cause permanent vision loss. If the patient experiences any symptoms, he needs to contact the eye care provider ASAP or go to the emergency room.

Angle Closure Glaucoma

KEY: Summary: * Dilation is a key component of an annual comprehensive exam, but it may also indicate more often in certain cases. * A complete history is key to determining indications, contraindications, and precautions when dilating. * Important components of the pre-dilation work-up include ____, ____, _____, ______, ______ * There are several techniques to measure IOP, and advantages and disadvantages with each. * Pre-dilation IOP and anterior chamber angle evaluation are important, particularly in cases where patients are at risk for angle closure glaucoma. It is important to make sure the patient is aware of the signs and symptoms.

History, VAs, Pupils, IOP, Anterior Chamber Evaluation