2 Chapter 2 Prelims
V550: Clinical Sciences
Lab Manual for Preliminary Testing
Introduction
Welcome to V550: Clinical Sciences! In this lab manual, you will find the schedule and instructions for each week of lab through your first proficiency. You will receive another manual for your next proficiency as this one only covers preliminary testing. You are always more than welcome to reach out if you have any questions!
Weekly Schedule:
Week 1: Intro to Visual Acuity, Externals/Pupils, NPA/NPC
Week 2: Into to Color, Stereo, EOMS, Visual Fields
Week 3: Proficiency 1 Practice
Week 4: Practice for Proficiency
Week 5: Proficiency 1: All Prelims
WEEK 1: Intro to Visual Acuity, Externals/Pupils, NPA/NPC
The first step is to wash your hands and clean ALL equipment that will come into contact with the patient. You will also want to make sure the patient is seated and comfortable. They should be at eye level with you as well. If not, be sure to adjust their chair.
Visual Acuities “VA’s”:
Explain to patient “we are going to test your vision now”
Set up: Overhead lights : ON
Stand light: for distance VA’s – off to side
for near VA’s – on near card
Distance VA cc “test your distance vision with your glasses on”
Start at 20/30 and work towards 20/20.
If worse than 20/25, pinhole. (you ONLY pinhole for distance!)
Instructions:
- Hand patient the occluder and ask them to cover their OS.
- Ask the patient to “Look on the chart and read the lowest line that you can without squinting.”
- Record the VA for the OD
- Have patient cover the OD with the occluder.
- Ask the patient to “Read the lowest line on the chart that you can.”
- Record the OS VA
- Ask the patient to “Read the lowest line on the chart that you can with both eyes.”
- Record the OU VA
Repeat for distance vision sc
Near VA cc “test your near vision with your glasses on”
Near card is held by patient @ 40 cm
Stand light is over near card
Instructions:
- Hand the patient NP card, and ask them to cover their OS.
- Ask the patient to “Look on the card and read the lowest line that you can.”
- Record the VA for the OD.
- Have the patient cover the OD with the occluder.
- Ask the patient to “Read the lowest line on the card that you can.”
- Record the OS VA
- Ask the patient to “Read the lowest line on the card that you can with both eyes.”
- Record the OU VA
Repeat for near vision sc
Near VA sc “test your near vision with your glasses off”
Near card is held by patient @ 40 cm
Stand light is over near card
Distance VA sc “test your distance vision with your glasses off”
Start at 20/400 and work towards 20/20.
If a patient is unable to see the 20/400 E sc, take their arm and walk them towards the screen until they can. Estimate distance (total distance = 20’). If unable to read the near card sc, bring closer until they can and estimate that distance as well (total distance = 40cm)
Results: If the patient only reads ½ the line or less, have them read the next line up.
Record: 20/30+2 (if they read 2 letters on the 20/25 line.)
If the patient reads more than half of the line, then record the following:
Record: 20/20-2 (if they read 4 letters on the 20/20 line and missed 2)
Record OD/OS/OU in 20/__ +/- __ form for both cc and sc for both distance and near vision.
Eye Dominance
Explain to patient “we are going to see which of your eyes is dominant”
Set up: Overhead light: ON
Stand light: ON and off to side
cc
Distance chart: isolated letter (one line above their worst corrected cc)
Instructions: “make a small triangle with your hands and looking through it,
focus on one letter of the chart.” Using the occluder, cover one eye and ask the patient if they can still see the letter. Then cover the other eye and ask again. Repeat this 3X while alternating the eye you cover first.
Results: whichever eye they can still see the letter with is their dominant eye.
Record this as “OD” or “OS”
Example of which line to display for eye dominance: If pt VA’s are OD: 20/20 and OS: 20/30, you would set the chart to 20/40 for eye dominance.
External Evaluation:
External Obs:
Explain to patient “I am going to look at the external features of your face and eyes”
Set up: Overhead light: ON
Stand lamp: ON and tilted towards pt
sc
Distance chart: 20/400 E
Instructions:
LLL: First, observe the lids, lashes and lacrimal apparatus. Instruct the patient to close their eyes. Starting temporally, shine the transilluminator tangentially on the patient’s face. Observe over the lash margin in an “H” pattern.
Conjunctiva: Instruct the patient to now open their eyes. Instruct the patient to look right, scan, then left, scan, then up and scan. Scan by following white sclera and using light to observe any irregularities.
Results:
Record LLL (lids, lashes, lacrimal apparatus): “-” or “+”
Record any abnormalities such as : lesions, papillomas, scars,
redness, crusting of lashes.
Record Conjunctiva: grade conjunctiva by scale:
Clear
Trace
1+
2+
3+
Record Symmetrical/Asymmetrical Pupil Shape:
Is it round, oval or irregular?
Record Color of Iris: Bl, Gr, Hz, Br
Anterior Chamber Angle: (External sub category) to measure depth of anterior chamber
Explain to patient “You may feel my hand on your face here as I use my light to look at your eye”
Set up: Overhead light: ON
Stand light: ON and tilted towards pt
sc
Distance chart: 20/400 E
Instructions: Hold the light to the side of the patient’s face about 2 to 3 cm from the lateral canthus on the plane of the iris with the light at a right angle to the LOS. You may need to use your fingers to steady light. Observe the nasal half of the iris for a shadow
Results:
Record Iris: flat or steep
Record Angle Grade: 0-4+ (with 4+ being no shadow) for OD/OS
Record Chamber Depth: deep or shallow
Here are some example photos to help understand this test:
Fissure Size: all same as External (sub category)
Explain to patient “I am going to measure the distance between your eyelids”
Set up: Overhead light: ON
Stand light: ON and tilted towards pt
sc
Distance chart: 20/400 E
Instructions: Instruct the patient to “look straight ahead at the big E. I will be touching the side of your face” Use the fissure scale on the toucan stick. Place the scale so it is bisecting the patient’s pupil. Line up the scale so that the lid margin matches up with one of the scale increments in mm.
Results: Record: Ptosis (+ or -) and Crusting (+ or -) and fissure size OD/OS
Expected values: no more than 0.5 mm difference between eyes.
If > 0.5 mm it would be ptosis.
Pupils
Pupil Shape: observe
Record: Round (R), Oval (O), Irregular (Irg)
Pupil Size:
Explain to patient “I’m going to measure your pupil size in the light”
Set up: sc
Distance chart – 20/400 Big E
In light:Overhead light: ON
Stand light: On and pointed towards pt
Instructions: Instruct patient “just look straight ahead for me at that Big E.” Use your pupil size gauge to bisect the OD pupil. Move it up and down until the gauge matches the patient’s pupil size. Repeat this for the OS.
Measure and record size OD/OS in mm in light.
Explain to patient “I’m going to measure your pupil size in dim lighting”
In dark: Overhead light: OFF
Stand light: Dimmed and off to the side
Instructions: Instruct patient “just look straight ahead for me at that Big E.” Use your pupil size gauge to bisect the OD pupil. Move it up and down until the gauge matches the patient’s pupil size. Repeat this for the OS.
Measure and record size OD/OS in mm in dim lighting.
Results:
Expected values: pupil size in dark should be at least 2 mm larger than in the light
(otherwise must be stated it is likely due to ambient lighting).
Direct and Consensual
Explain to patient: “I am going to now watch your pupils as they respond to my light”
Set up: Overhead light: OFF
Stand light: Dimmed and off to the side
sc
Distance chart – 20/400 Big E
Instructions:
- Instruct patient to “just look straight ahead for me at that Big E.”
- Hold your transilluminator directly below the OD’s LOS about 5-6 mm from the eye, and shine the light into the pupil. Be sure the light is only shining on one eye at a time. Hold for 2 seconds. Look for the speed of constriction of this (OD) pupil (Direct Response).
- Repeat for OS.
- Then, shine the light into the OS in the same manner as before. Hold for 2 seconds. Look for the speed of the constriction of the OD (Consensual response).
- Repeat by shining the light into the OD and evaluating the consensual response for OS.
Results: Record rate reaction speed (0-4 with 0 being no rxn and 4 being very fast).
__+ for OD/OS for both direct and consensual.
Tips on rating pupil speed:
0 – no response
1-little response at all (in elderly)
2-slow to moderate (kids up until teens & elderly)
3-pretty fast (usually early adult)
4-instantaneous constriction
APD: Afferent Pupillary Defect
Explain to Patient: “I’m going to check how your pupils react to light”
Set up: Overhead light: OFF
Stand light: OFF
Distance chart: OFF
Instructions: Instruct patient to “look where the distance chart was.” Hold the light under the LOS of one eye for 2 seconds. Snap your wrist and flip your light towards the other eye and hold the light under the LOS but at the pupil of the other eye for 3+ sec.
Repeat 3-6x (hold for 3 second each and watch for HIPPUS)
Results:
Record: If both constrict with no dilation other than hippus, (-) APD, if one eye dilates more than the other with direct light stimulus (+) APD.
NPC: Near Point Convergence
Explain to Patient:
“This will test your eye’s ability to come in when looking at something very near”
Set up: Overhead light: ON
Stand light: ON and over target
cc
BINOCULAR
In LOS -Use the PD stick and have the patient focus on the small letter v in the center of the smallest line (20/25). Start 30/40 cm from eye
Instructions: “I would like you to look at the little v in the center of the bottom line. As I move it forward, tell me when you 1st see the image break into two.”
- Tell patient what you are about to do.
- Place target on patient’s LOS and about 40cm from patient’s nose.
- Tell patient to, “Watch target carefully, and tell me when you see it break into two.”
- Move target toward patient’s nose at about 5mm per sec.
- Stop when the patient says they see two or one eye drifts outward (BREAK POINT)
- Ask the patient to close their eyes and measure distance from there to bridge of nose (BON) using PD stick.
- Then move target back until the patient reports “one” object again (RECOVERY POINT)
- Ask the patient to close their eyes and measure the distance from there to BON using PD stick.
Repeat 2X, record the average
Results: Record both breaking and recovery.
Expected value: at least 5-10 cm break; recovery should be within 2 cm of that.
If patient does not report a break, you would say to BON (bridge of nose): no recovery and record “BON/x”
NPA: Near Point Accommodation
Explain to Patient: “I’m going to check your eye’s ability to focus”
Set up: Overhead light: ON
Stand light: ON and over target
Below LOS – Use the PD stick and have the patient focus on the small letter v in the center of the smallest line (20/25). Start 30/40 cm from the eye
*slower than NPC
cc
Instructions: This test is performed monocularly and binocularly.
- Start by having the patient occlude OS (test OD first).
- Instruct the patient “again, look at the small v on the lowest line and let me know when this letter first starts to blur.”
- Holding below LOS, slowly bring in target (slower than NPC).
- After report blur, “can you blink and clear it up?”
If they cannot clear it with a blink, have patient close their eye and measure the distance using PD stick.
- Repeat for OS, and binocularly.
Results: Record: OD/OS/OU (in mm)
Expected values:
<35: better than 12 cm (OD/OS/OU should be w/i 1 or 2 cm)
Presbyope: Hofstetter’s formula
MIN IS 4 CM
WEEK 2: Intro to Stereo, Color Vision, EOMS, Visual Fields
Stereopsis
Explain to Patient: “I am just going to check your depth perception”
Set up: ALSO WEARING POLARIZED GLASSES
Overhead light: ON
Stand lamp: ON and on book
cc
DR HOLD BOOK AT 40 CM
Instructions: starting on right page of book,
- Ask the patient to find one of the objects in the top half while pointing.
- Ask the patient to find one of the objects in the bottom half while pointing.
Move on the left page of book,
- Ask about the R + L box: “What do you see in this box?”
- Ask the patient about boxes with circles 1-10: “Can you tell me which circle in this rectangle looks like it is popping off the page or closer to you?”
- Continue and then stop when they miss TWO in a row.
Results: Record use the cheat sheet to find,
+RDS, __” Method: Randot
Expected values: 20 sec of arc for most adults (fail = 60”, so 40” is passing)
120 sec of arc for children
Color
Explain to Patient: “This will check your color vision”
Set up: Overhead light: ON
Stand lamp: ON and on book
cc
MONOCULAR
Dr will hold book – at 50 cm
Instructions:
- Cover one eye and ask the patient to confirm that there is no problematic glare on the booklet. Then, instruct the patient “point and tell me what shapes you see on each page.”
The first 4 are test plates and don’t need to be tested for OS, but still record __/10 for OS.
It is very important to not have the patient touch the book. The oils from their fingers can discolor them!
Results: Record: __/10 for OD and OS
Method: HRR
Expected values: 10/10
EOMS (H test)
Explain to patient: “This next test will check your eye muscles”
Set up: Overhead light: ON
Stand lamp: ON and on pt’s face
Use transilluminator on ½ illumination
sc
Instructions: Instruct the patient “I would like you to follow the light with your eyes only.” Then, using transilluminator on half brightness, perform H pattern and then converge at center. Be sure to ask patient: “at any point, did you experience any pain or double vision?” after the test.
Results:
Record: SAFE (smooth, accurate, full, extensive)
(-) pain
(-) diplopia
Confrontation VF
Explain to patient: “This will check for defects in your side/peripheral vision”
Set up: Overhead light: ON
Stand lamp: ON and up between pt and dr
sc
MONOCULAR
Instructions:
- Center yourself between patient at about an arm’s length away.
- Close your OD (if you plan to test your patient’s OD).
- Instruct patient: “cover your right eye. Look straight ahead at my open eye. I am going to hold up 1, 2 or 4 fingers and I want you to tell me how many fingers you see while still looking here at my eye.”
- Bring fingers midway between you and patient. Your palm should be facing you.
Can use 1, 2, 4***
Z pattern (4 quadrants)
Results: Record: FTFC (full to finger counting) and specify which eye.
In a normal setting, you would test both eyes.
For this class, you will only be required to test one eye during the proficiency.
ACC: Accommodative Response
Explain to Patient: “Checking how your pupils respond when looking from
distance to near”
Set up:
Overhead light: ON
Stand light: ON and over target
Dr holds near stick held at 10 cm
Use the letter “O” on the 20/80 line on PD stick
cc
Big screen: 20/400 E
Instructions: Instruct patient to “continue looking at the distance chart and when I tell you, look at this small letter “O”. I will have you look back and forth a few times, so just follow my instructions.” Hold the near stick approximately 10 cm from pt and just under the LOS. Both pupils should constrict equally when looking at near.
Repeat 3-4x
Results: Normal response is to see dilation when going from near to far and constriction of pupils when coming near from far. This is recorded as (+/+). If these movements are not seen, it would be recorded as (-/-).
Week 3, 4: Proficiency 1 Practice
DUE: Preliminary Video on September 11
Week 5: Proficiency 1: All Prelims