Visual Acuity TestingVisual Acuity Testing

Lynn Lawrence, CPOT, ABOCLynn Lawrence, CPOT, ABOC

Define Visual AcuityDefine Visual Acuity

The The measurement measurement of the ability of of the ability of the eye to see the eye to see detaildetail

The procedureThe procedure

LightingLighting Patient positionPatient position Distant/nearDistant/near OccluderOccluder Pin-hole… what Pin-hole… what

makes it better?makes it better? Plus lensPlus lens

The Hardest AcuityThe Hardest Acuity

What is the most difficult acuity you What is the most difficult acuity you have ever takenhave ever taken

Were you prepared for it?Were you prepared for it? Are children difficult?Are children difficult? What do you do with the parents?What do you do with the parents? What happens when it is taking too What happens when it is taking too

long?long?

DocumentationDocumentation

Test distanceTest distance Test targetTest target Pupil reactionPupil reaction

– Constriction/Constriction/distdist

– Dilation/nearDilation/near CorrectionCorrection

RobotsRobots

Don’t be a robotDon’t be a robot Know why you are testing a patientKnow why you are testing a patient Know how the test is to be performedKnow how the test is to be performed Know what is WNLKnow what is WNL Know how to document the findingsKnow how to document the findings Know when to testKnow when to test When in doubt…test it outWhen in doubt…test it out

Visual AcuityVisual Acuity

Baseline dataBaseline data Quantification of visual statusQuantification of visual status Sets criteria to help patient Sets criteria to help patient

achieve better visionachieve better vision

Visual AcuityVisual Acuity

TypesTypes– NearNear– DistantDistant

ChartsCharts– SnellenSnellen

AlignmentAlignment ConversionsConversions Test DistancesTest Distances

Types of Acuity ChartsTypes of Acuity Charts

SnellenSnellen Metric (Bailey-Lovie)Metric (Bailey-Lovie) Low Vision Charts Low Vision Charts Illiterate ChartsIlliterate Charts

-Landolt “C” or rings-Landolt “C” or rings

-Tumbling “E”-Tumbling “E”

-Lighthouse charts-Lighthouse charts

ProcedureProcedure Always observe patient.Always observe patient. No squinting. Why?No squinting. Why? When do you obtain pinhole acuity?When do you obtain pinhole acuity? Visual acuity better with one eye or Visual acuity better with one eye or

two?two? Note any consistent pattern in the Note any consistent pattern in the

letters missed by the patient. letters missed by the patient. Why?Why?

Preschool ChildrenPreschool Children

Allen Picture ChartAllen Picture Chart

11947R Courtesy of Richmond Products

Snellen FractionSnellen Fraction

NumeratorNumerator -Represents the testing distance in -Represents the testing distance in

feet or metersfeet or meters - 20/___; 6/_____- 20/___; 6/_____• DenominatorDenominator -Represents the distance at which -Represents the distance at which

the letter subtends a 5-minute angle the letter subtends a 5-minute angle or arc in distance or meters. Also or arc in distance or meters. Also referred to as the letter sizereferred to as the letter size

Techniques for TestingTechniques for Testing

Monocular and binocularMonocular and binocular With and without RxWith and without Rx Distance and near Distance and near Pinhole acuity (20/30)Pinhole acuity (20/30) Testing errorsTesting errors What happens when a patient can’t What happens when a patient can’t

see the largest letter at 20 feet?see the largest letter at 20 feet?

Types of Acuity Charts Types of Acuity Charts

SnellenSnellen Metric (Bailey-Lovie)Metric (Bailey-Lovie) Low Vision ChartsLow Vision Charts Illiterate ChartsIlliterate Charts

– Landolt “C” or ringsLandolt “C” or rings– Tumbling “E”Tumbling “E”– Lighthouse chartsLighthouse charts

ProcedureProcedure

Patient unable to see the big Patient unable to see the big “E”“E”– Walk up method (15/400, 10/400, Walk up method (15/400, 10/400,

5/400)5/400)– Count Fingers- CF @ _____ftCount Fingers- CF @ _____ft– Hand Motion- HM @______ftHand Motion- HM @______ft– Light LocationLight Location– Light PerceptionLight Perception

Near VA’sNear VA’s

Test distance is Test distance is 16 inches or 40 16 inches or 40 cmcm

Proper lightingProper lighting

PinholePinhole The pinhole test is used to The pinhole test is used to

confirm whether or not confirm whether or not refractive error is the cause of refractive error is the cause of decreased visual acuity.decreased visual acuity.

DocumentationDocumentation

Connect the Dots!Connect the Dots!

Listen to the patientListen to the patient Watch the patient when testing ptWatch the patient when testing pt You need to know what direction You need to know what direction

to goto go

Refractive HistoryRefractive History

Past history of Past history of corrective lensescorrective lenses

Current corrective Current corrective wear…recent Rx? wear…recent Rx?

-age of correction-age of correction

-state of -state of correctioncorrection

-quality of vision-quality of vision

Case HistoryCase History

This is a legal documentThis is a legal document… … write everythingwrite everything

Use the components of case HxUse the components of case Hx– Chief complaintChief complaint– Medical and ocular historyMedical and ocular history

PatientPatient FamilyFamily

– Occupation and avocationOccupation and avocation– Hobbies…piano teacher-vs-cross Hobbies…piano teacher-vs-cross

stitching stitching

Pre-Pre-TestingTesting

Visual AcuityVisual Acuity - Aided and Unaided- Aided and Unaided - Distance and Near- Distance and Near Letter size calibrationLetter size calibration - 20/200 = 87mm at 20 feet- 20/200 = 87mm at 20 feet

Case HistoryCase History

Chief ComplaintChief Complaint Reason for the patient visitReason for the patient visit recorded in Patient’s own words.recorded in Patient’s own words.

- Ask all the questions necessary to aid your doctor - Ask all the questions necessary to aid your doctor in discovering the root cause of the patients in discovering the root cause of the patients current condition (ie. Who, what, where, how, current condition (ie. Who, what, where, how, how long, How old is patient, pain assessment, is how long, How old is patient, pain assessment, is there anything that brings relief, last eye exam, there anything that brings relief, last eye exam, last physical exam, illicit and legal drug use, last physical exam, illicit and legal drug use, dosage/frequency, alcohol use/amount, and dosage/frequency, alcohol use/amount, and patient/family medical history)patient/family medical history)

Ocular History Cont…Ocular History Cont…

Rule out specific Rule out specific ocular problems or ocular problems or conditionsconditions

surgerysurgery injuryinjury vision trainingvision training MedicationsMedications AllergiesAllergies refractive historyrefractive history

A great question: Are you wearing your most current Rx?

Ocular SymptomsOcular Symptoms

Ask open ended Ask open ended questions and questions and document what document what the patient saysthe patient says

itchingitching burningburning tearingtearing rednessredness irritationirritation other symptomsother symptoms

Ocular History Cont…Ocular History Cont…

Rule out specific Rule out specific ocular problems ocular problems and conditions, and conditions, such as:such as:

-glaucoma-glaucoma

-cataracts-cataracts

-keratoconus-keratoconus

-surgery-surgery

-previous injuries-previous injuries

SOAPP FormatSOAPP Format

Subjective… Subjective… Chief ComplaintChief Complaint

Objective… Objective… test test resultsresults

Assessment… Assessment… for the O.D. onlyfor the O.D. only

Plan… Plan… for the O.D. for the O.D. onlyonly

Prevention… Prevention… duty to warn/counselingduty to warn/counseling

Document Pain Document Pain AssessmentAssessment If the patient is in If the patient is in

pain, you must pain, you must evaluate the level evaluate the level of painof pain

Ask if anything Ask if anything relieves the painrelieves the pain

Ice Ice Pain associated Pain associated

with traumawith trauma Penetrating injuriesPenetrating injuries

Recording Visual Recording Visual AcuityAcuity

Verify with your Verify with your doctordoctor

DDVVA 20/ NA 20/ NVVA A 20/20/

CC SC CC SCCC SC CC SC

Thank youThank you