Dilation Protocol Flashcards
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.
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)
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
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
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”
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.
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).
KEY: Contraindications and Precautions
You must dilate with care with patients with a recent ______.
head trauma
KEY:Contraindications and Precautions
Also, unilateral pharmacologic mydriasis may masquerade as a sign of intracranial disease (_______).
Hutchinson’s pupil
KEY: What is done in a pre-dilation work-up?
- Case History
- Visual Acuity
- Pupil Reflexes
- Intraocular Pressure
- Anterior Chamber Angle
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
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.
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.
KEY: Why check intraocular pressure before a DFE?
It serves as a baseline against which post-dilation IOP can be compared.
KEY: What is a normal range of IOP?
8 to 23 mm Hg
KEY: The average intraocular pressure is ____.
15.5 mm Hg
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.
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.
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?
- Quick
- No anesthetic required
- Can be delegated
- No epithelial damage
- Measure through contact lenses
It can be done in a pre-testing room.
What are disadvantages of NCT?
- Cost
- Large Instrument
- Less Portable
- Must be Factory Calibrated
- Multiple readings necessary (ocular pulse)
- 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?
- 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. - RACE– Asians and northern indigenous people who have more narrow anterior chamber angles
- SEX– 3x more women get it
Interestingly, men and women are affected equally among African-Americans
What are causes of Narrow Angle Glaucoma?
- HYPEROPIA
- Pupillary Block*
- Iris Plateau*
- 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:
- Severe Eye Pain
- Blurred vision and/or seeing HALOS around lights
- Headache
- Nausea and vomiting
- Profuse tearing
- Red Eye
- 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
