How can pupil constriction be tested when light response is absent/abnormal?
By inducing accommodation and measuring the constriction due to the accommodative response. Used ONLY when light response is abnormal/ absent. Under these conditions:
- Constriction = iris has normal innervation, but there may be an APD.
- No constriction = possible paralysis of iris sphincter muscle.
How is a RAPD detected?
Detected by swinging flashlight test.
How long should light be shined on the eye during the swinging flashlight test?
3-5 seconds
Under what conditions is the swinging flashlight test done?
o No room illumination
o Shine light in OD for 3 seconds then rapidly move to OS and hold for 3 seconds
o Normal pupils will stay equally constricted
o Repeat 2-3 times
Under what conditions is pupil constriction response checked?
o Done in dim room at 5-6 cm
o Check direct and consensual response for 2 seconds
How is pupil constriction response graded?
Based on how brisk constriction is upon exposure to light. On a scale of 0-4.
0= no response 4=brisk response
How is a RAPD scored?
o Pupil dilates immediately: Grade 3-4+
o Dilates after a few seconds: Grade 1-2+
o Pupil constricts initially but then dilates: Trace APD
o Can also be quantified by neutral density filter
How is pupil size measured?
o Remove glasses
o Look at 20/400 letter
o Use pupil gauge on PD and measure to nearest 0.5mm; note pupil shape (round or oval)
o Measure in bright and dim light
What does PERRLA stand for?
Pupils Equal, Round, Reactive to Light and Accommodation
How is an Afferent Pupillary Defect in the left eye noted?
(+) APD OS
What do the following abbreviations mean and what do they describe?
R/R O/R Irg/R
Round and Reactive
Oval and Reactive
Irregular and Reactive
They describe pupil shape and reactivity to light
What does the finding D/C mean?
Direct and consensual pupillary response to light.
What is the procedure for checking the pupillary Accomodative Response?
- Direct patient to the 20/400 letter at distance
- Switch gaze to a near card 10-40cm from their eyes
- Recheck 2-3 times looking for both dilation and constriction
- Note the briskness of the constriction
- Can check during NPC measurement
What factors affect the measuring of IOP?
- Diurnal Variation: Highest early AM, Lowest early PM
- Arterial pulse: 2-4 mm Hg variation
- Position: 2-3 mm Hg higher when supine vs seated
- Vascular integrity: Poor perfusion from the carotid will reduce aqueous production on the ipsilateral side
- Arobic exercise: can cause 20% IOP reduction
- External globe pressure
- Medication: beta blockers, marijuana and alcohol reduce IOP; steroids may increase IOP
- Trauma and inflammation: inflammatory cells clog trabecular meshwork
- Corneal hysteresis/ thickness: thicker corneas lead artificially high IOP measurements
What IOP measurement technique is the standard of care in optometry?
Goldman tonometry. You will be held to this standard in a court of law.
What are some advantage of NCT?
- Displaces virtually no aqueous so it is repeatable
- Fairly accurate up to 30 mmHg
- Requires no anesthetic
- Can be used without risk of contamination in eye infections
What are some disadvantages of NCT?
- Need to take repeated readings since one reading might be measured at the height of the ocular pulse
- Higher pressures become inaccurate
What is the average IOP?
15.5 mmHg
What range is considered a normal for IOP?
8-23 mmHg
A diurnal IOP variation of more than ____ is considered significant.
4 mmHg
IOP asymmetry of more than ____is considered significant.
2 mmHg
How is IOP recorded?
Eye: measurements @ time , equipment used
ex. OD: 16, 14, 14 mmHg @ 4:15 pm Pulsair NCT
Who is the “father” of classic perimetry?
Traquair
What type of perimeter did Goldman introduce?
Bowl perimeter.
-Controlled: Retinal adaptation, fixation, target size and intensity
