Dilation Protocol Flashcards
Purpose of dilated fundus exam
- improve visualization of the fundus
- improve visualization increases detection rate of abnormalities
- pharmological dilation is generally required for the thorough eval of ocular structures
Indications of a dilated fundus exam
-routine exam on ALL patients
For pts between the ages of 18 and 39, a comprehensive eye examination on including ocular health evaluation is recommended at least every…
2 years
How often should patients over 65 have comprehensive eye exams?
Annually in the absence of a diagnosed ocular condition
When would more frequent monitoring with dilation be indicated?
In a patient with a previous diagnosis of ocular pathology
What type of patients should be monitored more frequently with a dilation?
- pts at higher risk of introcular disease (DM, high myopia)
- pts with symptoms or signs indicative of intraocular disease (flashing lights (photopsia), floaters, and reduced VA
Contraindications and precautions of dilated fundus exam
- sensitivities to pharmacologic agents
- narrow anterior chamber angle
- presence of iris-fixed IOL
- documentation/preservation of pupil status
Sensitivities to phenylephrine
Adrenergic supersensitivtiy
Sensitivity to cyclopentolate
Spastic paralysis and brain damage
What are most people sensitive to if they are sensitive at all to pharmacological agents?
Sensitivity to preservatives
Narrow anterior chamber depth
Consider prophylactic peripheral laser iridologist prior to DFE if angle appears susceptible to closure on gonioscopy
Presence of iris-fixes IOL and dilation
- Risk of IOL dislocation with pupil dilation
- DOCUMENTATION
- they usually have a card the surgeon has given them but always check anyways to CYA
Documentation/preservation of pupil size
- pupil status may serve as an important vital sign in patients with intracranial disease
- dilate with care in patients with recent history of head trauma
- unilateral pharmacologic mydriasis may masquerade as a sign of intracranial disease (hutchinson’s pupil)
Pre dilation work up
- history
- VA
- pupil reflexes
- IOP
- anterior chamber angle
History
- vitally important in guiding the DFE
- aids in what you are looking for during ophthalmoscopy
What to get from history
-demo, occupation, hobbies
-CC plus FOLDARQ
-ocular hx (LEE, visual aids)
-med hx
LME
ROS
Meds, allergies
Family ocular and med hx
Social hx
VA before dilation
-always performed prior to any other procedure for medico-legal reasons
What does VA help detect problems with?
- refractive error
- optical media
- retina
- optic nerve
- visual pathways
- there are serious disorders that do not affect VA
What do you tell the pt you are going to do for VAs?
“Im going to check your vision” then follow with proper patient directions
-watch them and make sure they aren’t cheating
If you cant get patient to 20/20
State a reason why you cannot
Pupil reflexes before dilation
- screen for abnormalities prior to dilation
- especially important to search for an afferent pupillary defect in patients with decreased acuity in one eye
Should there be a difference between direct and consensual when doing swinging flashlight test?
No
Will direct or consensual be stronger in APD?
Consensual
What do you tell patient when doing pupils?
“Im going to check how your eyes react to light)
Normal recording for pupils
Pupils Equal Round Reactive to Light with no APD
IOP before dilation
-serves as a baseline against which post-dilation IOP can be compared
Normal range of IOP
8-23mmHg
Average IOP
15.5mmHg
A difference in pressure readings of more than ____ between the two eyes is considered significant
2mm
Diurnal variations of IOP
3 to 4mm Hg are considered normal
When is IOP higher?
AM
POAG patients will experience what following dilation with an anti-cholinergic agent?
A mild transient elevation of IOP
What are the ways you can measure IOP?
- digital palpation
- NCT
- goldman applanation tonometry
What is the gold standard for IOP measuring?
Goldman applanation tonometry
Digital palpation (IOP)
- simplest and least expensive technique for approximate IOP assessment
- used for conditions where tonomtery is not possible
Advantages of digital palpation
- simplest, least expensive
- instrumentation not required
- useful when external tonometry is not possible, for example, after penetrating keratoplasty or corneal scarring
- may be the only feasible technique in patients who are unwilling or unable to undergo other methods of IOP measurements
Disadvantages of digital palpation
- least accurate method of IOP
- palpation is best avoided in eyes with significant trauma or in certain post op conditions
Technique for digital palpation
- clean hands
- say” going to check pressure in eyes”
- tell them close their eyes
- feel eyeballs with fingertips through closed lids
During digital palpation if the eye feels soft
IOP <6-8
-if pts eyes feel like this, the IOP is probably too low
During digital palpation if eye feels hard
IOP>30
-feel bony part of chin, if patients eyes feel like this, the IOP is probably too high
What should the patients eye feel like if the pressure is normal?
Like the tip of your nose
Recording digital palpation
-low to palpation
-normal to palpation
-high to palpation
INCLUDE THE TIME
NCT
The cornea is applanated by an air pulse, and IOP is measured without direct contact between the eye and the instrument
When is NCT useful
When contact techniques are contraindicated, or as in the case of a red eye of infectious origin
Advantages of NCT
- quick
- no anesthetic required
- can be delegated
- no epithelial damage
- measure through contact lenses
Disadvantages of NCT
- cost
- large instrument
- less portable
- must be factory calibrated
- multiple readings necessary (ocular pulse)
- most patients are apprehensive
What do you tell patient you are doing for NCT?
“Im going to check the pressure in your eyes, please keep both eyes open and look at the light, you will feel a light puff of air
Set up for NCT
- turn instrument on
- disinfect forehead and chin rest
- adjust table and chin rest to align the patients outer canthus with the notch on the upright supplier of the headrest
Recording NCT
NCT @ 10:30am
OD 15mmHg
OS 15mmHg
Anterior chamber angle assessment
A narrow anterior chamber angle increases the risk of angle closure glaucoma
Shadow test
-anterior chamber depth can be estimated with oblique penlight illumination across the surface of the iris
Slit lamp eval of anterior chamber angles
Van Herick technique of peripheral anterior chamber death estimation
Gonioscopy
The gold standard for anterior chamber angle eval
When is shadow test used to eval anterior chamber angle?
- when slit lamp is not available
- gross estimation method
- light is presented from the temporal side
- shadow provides a rough estimate of chamber depth
- full illumination
Shadow test technique
- instruct patient to look straight ahead
- light is presented from the temporal side
- shadow provides a rough estimate of chamber depth
When is shadow test useful?
For basic screening where availability of more sophisticated equipment may be limited
If there is a narrow angle, what will happen during shadow test?
There will be a larger shadow
Open angle in shadow test
Will show little to no shadow
What do you tell patient during shadow test?
-im going to take a quick measurement using this light
Recording shadow test
Anterior chamber angle estimation
- OD grade 4
- OS grade 3
What can happen to patients with narrow anterior chamber angles after dilation?IO
They can develop acute angle closure glaucoma, with a rapid and severe elevation of IOP
What should be checked in persons with narrow angles post dilation?
IOP
Warning pts with narrow angles
Warn about the signs and symptoms of angle closure glaucoma and instruct patient to contact you in the symptoms occur
Documenting pts with narrow angles
Document warnings and instructions gave to patients
Risk factors for narrow angle glaucoma
Age
Race
Sex
Age as a risk factor for narrow angle glaucoma
As we grow older, the lens inside out eyes gets larger, increasing the risk for pupil block. Also, the anterior chamber tends to become increasingly shallow, and the drainage angle may narrow as we age
Race as a risk factor for narrow angle glaucoma
Asians, as well as inuits and other northern indigenous people, who have anatomically narrowe anterior chamber angles than whites, have a higher incidence of angle-closure glaucoma
Sex as a risk factor for narrow angle glaucoma
- 3x more likely in women than in men
- among African americans, men and women appear to be affected equally
Causes of narrow angle glaucoma
- hyperopia
- pupillary block
- iris plateau
- tumors and other causes
Hyperopia as a cause of narrow angle glaucoma
People how are farsighted are more likely to have eyes with shallow anterior chamber and narrow angles, increasing their risk for angle closure glaucoma from pupil dilation or aging changes in the eye
Signs and symptoms of angle closure glaucoma
- severe eye pain
- blurred vision/halos
- headache
- Nausea and vomiting
- profuse tearing
- red eye
- dilated pupils
Angle closure glaucoma as an ocular emergency
- if not reduced within hours, may cause permanent vision los
- if experiencing symptoms, need to contact eye care provider ASAP or go to hospital ER
What is a key component of an annual comprehensive exam, but may indicate more often in certain cases?
Dilation
What is key to determine indications, contraindications, and precautions when dilating?
A complete history
What are important components of pre dilation work up?
History VAs Pupils IOP Anterior chamber eval
Predication IOP and anterior chamber angle eval
Important especially where patients are at risk for angle closure glaucoma. It is important to make sure the patient is aware of the signs of the symptoms
