Hypertension Classification

V Visual Acuity

o Purposes:

§ To establish a baseline

§ Legal reasons (driver’s licenses, insurance claim, pension, and disability based on legal blindness)

· Legal blindness: 20/200 or worse in better eye OR less than 30 of visual field in the widest meridian of the better eye

§ Monitor progression or improvement of eye disease

§ Guide for the rest of the exam (prediction of refractive error, correlation of data, determines additional testing)

o Always the first test performed after history

§ Exception: chemical burn/spill; irrigate first, then check VA

o Definition: the resolving power of the eye, or the ability to see two objects as separate

§ “Normal” resolving power is defined as the ability to detect a gap with a width of 1 min of arc

o VA is highest at the fovea and decreases with increasing retinal eccentricity

o VA best if pupil is 2-5 mm

o Types

§ Minimum Detectable Resolution (minimum visible): the ability to distinguish an object from its background

§ Minimum Separable Resolution (minimum resolvable): the ability to resolve two or more spatially separated targets

· Gratings, bars, Vernier acuity, preferential looking

§ Recognition Resolution (minimum legible): the ability to recognize letters, numbers, and geometric forms

· Snellen, Landolt C, Tumbling E

o Snellen acuity chart is the universal method of measuring VA

§ Snellen optotypes: width of each stroke is equal to the width of a gap on that line

· “Best” letter is E (3 strokes and 2 gaps)

· “Not as good” letters are T and L ( no gaps)

§ At 20 feet, a 20 foot optotype subtends 5 min of arc

· Its details each subtend 1 min of arc

§ 20/20 letter is defined as a letter that has a height (x) such that it subtends 5’ arc at 20 ft

· Letter height can be altered with test distance

· Details (gaps and strokes) each subtend 1’ arc at 20 ft

§ Utilizes a “folded” room/operatory system

· Projector with letters, 2 mirrors and a screen

· Test distance= patient to mirror + mirror to screen

o MAR (minimum angle of resolution) in minutes of arc is equal to the reciprocal of the decimal acuity value or the Snellen fraction

§ Snellen fraction = 1/MAR

§ 20 ft (6m) is considered optical infinity, which is defined as the distance at which no accommodation is being used

§ Snellen fraction = testing distance

distance at which the smallest letter read subtends an angle of 5’ of arc

· Also described as the distance at which a “normal” eye can see the smallest letter read by this patient

o Snellen equivalent is used when VA is taken at a distance other than 20 ft or when other nomenclature is used

§ It is better to report the actual acuity, not the equivalent

o Limitations:

§ Number of letters tested per line changes as you move down

§ Letter sizes between lines do not change by a constant ratio

§ Between row and between letter spacing is not proportional to the letter size

§ Legibility for optotypes often varies

o Standard Chart Specifications

§ Chart luminance: at least 10 foot lamberts

§ Chart contrast: at least 90%

§ Subdued room illumination to enhance chart contrast

· Uncorrected refractive error is more likely to impact VA when pupils are slightly dilated

o Distance VA should be performed during ALL patient encounters

§ Procedure

· Seat patient comfortably and dim lighting

· VAs taken without correction(sc) and then with correction(cc)

o Minimizes chance of patient memorizing

· Clean occluder with alcohol swab

· Begin with full chart open and ask “Which of these is the smallest line of letters that you can read?”

· Isolate smallest LOL that the patient can read; continue to scroll down to the next LOL and have patient read it; stop when the patient is unable to read the entire LOL

o Find the patient’s threshold

· OBSERVE the patient (no squinting, cheating, leaning forward, etc)

o Observe the speed and degree of difficulty

· Record VA as the smallest line in which not more than 2 letters were missed for OD, OS, OU

o The number at the end of each line signifies the level of acuity

o Some use several 20/20 lines to minimize memorization

o “normal” best-corrected VA is 20/20

§ Corrected visual acuity (best corrected VA) is measured with the best refractive correction in place

§ Habitual visual acuity is measured with patient’s own spectacles/CLs

o Near VA performed during full/comprehensive exam and if they have a near vision complaint

§ Procedure

· Use full illumination: stand lamp on recording card

· Done without, then with near correction

· Measure the distance from the patient’s spectacle plane to the reading card in cm

· Cover OS and instruct to “Read the smallest paragraph that you are able to”, switch to cover OD, and then remove to read with both eyes open

· Re-measure the working distance with their correction

· Record working distance (in meters!) over the smallest print read for OD, OS, OU

§ M system: a 1M letter subtends 5’ of arc at 1 meter

· Allows patient to hold card at their desired reading distance

§ Reduced Snellen system:gives the appearance of expressing the distance VA that is equivalent to the near VA

· Should NOT be used for near VA (not appropriate to use a term that suggests a test at 20 ft when that distance is not relevant to near vision)

§ Jaeger system: indicates the size of the print by the letter J followed by a number

· Poor system because there is no standardization of the Jaeger sizes and there is no intrinsic meaning to the “J” number

o Pinhole testing: a measure of potential visual acuity

§ Nullifies small amounts of refractive error by 1) increasing the depth of focus and 2) decreasing the size of the blur circles

§ Most effective diameter is 1.32 mm

§ If VA improves with pinhole, suggests that refractive error is probably the cause of the reduced VA

§ Done when entering acuities are 20/40 or worse (based on better VA)

§ Record PH followed by VA obtained

· If no improvement, record PHNI

§ Super Pinhole, PAM (potential acuity measure) and laser interferometer are commonly used to determine potential VA before cataract surgery

o Brightness Acuity Test (BAT): used when you suspect acuity would be worse in a glare situation

§ VA with BAT is worse than without BAT for patients who have glare problems

o Alternative distance VA charts

§ OKN drum: cortical function only; objective test

§ Teller acuity cards: infants, non-responsive patients

§ Tumbling E: preschool, illiterate or non-verbal patients

§ LEA chart: children

§ Allen figures: children

§ Landolt C:

§ HOTV chart: amblyopes

· Each letter is surrounded by crowding bars

· Amblyopia: decreased VA (not correctable to 20/20) NOT due to pathology

o Snellen chart produces contour interactions (slow responses, some correct responses over a wide range of letter sizes, correct end-letter responses, out of order responses, perform better with isolated lines or letters)

§ Feinbloom chart: patients unable to see the 20/400 E on Snellen

· Full illumination and test distance of 5 or 7 ft

· Record test distance over smallest number size seen

o Alternative near VA charts (used during low vision)

§ Bailey-Love Chart: patients unable to see large print on other cards

· Space between the letters is equal to the letter width (prevents crowding effect)

· 5 letters on each line

· Between row spacing is equal to the height of the letters in the smaller row

§ Lighthouse cards

o Other measures of VA

§ Light perception (performed at ~ 1 ft)

· LPP: light perception with projection

· LPO: light perception only

· NLP: no light perception

§ Hand motion (used as last ditch effort when Feinbloom efforts exhausted)

§ Count Fingers

§ “Fix and follow”: unresponsive patients

· MUST ALWAYS ATTEMPT TAKING VISUAL ACUITIES

o Correlation of VA and refractive error

§ General rule: each 0.25DS of uncorrected refractive error accounts for ~ 1 line of Snellen VA

· For cylinder, take spherical equivalent (sphere + ½ cyl)

· For oblique axis, add a line for the axis

· Patient must have NO accommodation or be cyclopleged

V Pupil Testing

o Pupil performs 3 primary functions

§ Controls entering light

§ Modifies depth of focus (inverse relationship)

· Smaller pupil increases depth of focus

§ Varies optical aberrations (smaller has less aberrations)

o Should be performed during ANY patient encounter regarding eye health

§ Important because it is a neurological test that can detect optic nerve disease, brain mass and aneurysm

§ Gross examination can detect iris abnormalities, media opacities, and leukocoria

o Shape

§ Pupils should round and centered within the iris on optic axis

§ Irides should be of the same color

· Abnormalities

o Corectopia: displaced or misshapen pupil

o Ectopic pupil: significantly decentered

o Polycoria: more than one pupil

o Heterochromia: iris color different between eyes or between different areas in one eye

o Aniridia: absence of iris, therefore non-existent pupil

o Size

§ Average of 3.5 mm in adults under normal illumination

§ Become smaller after adolescence due to senile miosis

§ Should equal one another within 1 mm

· Anisocoria: unequal pupil size

· 20 % have physiologic anisocoria

§ Controlled by the autonomic nervous system

· Iris dilator muscleà dilates; sympathetic innervation

· Iris sphincter muscleà constricts; parasympathetic innervation

o Pupillary pathways

Afferent

· Light enters pupilà impulse in retina (PR and ganglion cells)à optic nerveà optic chiasm: ½ cross, ½ ipsilateralà optic tracts to superior colliculià pretectal nuclei of hypothalamusà crossed and uncrossed fibers to EWà synapse with efferent fibers

Parasympathetic efferent

· From EW nucleus travels with CN III (inferior division)à cavernous sinusà pierces globeà deviates from CN III and synapses at ciliary ganglionà postganglionic fibers reach iris sphincter via short ciliary nerves

o 97 % of the fibers control accommodation (ciliary body)

o Only 3 % innervate the sphincter

Sympathetic efferent

· Hypothalamusà synapses at ciliospinal center of Budge (C8-T4)à 2^nd order neurons leave spinal cord ascending close to the apex of lungà synapses at superior cervical ganglionà 3^rd order neurons follow the ICA’s to the globeà iris dilator via the long ciliary nerves

· Sympathetic innervation reaches Muller’s muscle in upper lids

o Response to light

§ Miosis (=constriction) occurs via parasympathetic innervation

· Some latency in initial constriction is normal (depends on brightness and age)

§ Direct response: response that occurs in one eye while the light is shone in that eye

§ Consensual response: response that occurs in one eye while the light is shone in the other eye

§ Pupillary escape: gradual and partial re-dilation without change in light intensity

§ Pupillary unrest or hippus: small oscillations in pupillary diameter that occur during maintained stimulation

· Due to normal fluctuation in sym/parasym equilibrium

o Response to near

§ Independent of retinal illumination

§ Near reflex is ALWAYS present when direct light reflex is intact

§ Near triad: pupil constriction, convergence, accommodation

o Swinging flashlight test

§ Compares the strength of the direct pupillary response with that of the consensual response

§ Detects afferent pupillary defect due to retinal abnormalities or optic nerve pathway anterior to LGN (APD or RAPD)

o Procedure

§ Remove spectacles and examiner positioned off to one side

§ Use a distant, non-accommodative target (2-3 lines above VA)

§ Measure pupil size under normal lighting conditions

· Expected findings: should equal one another

o Size in bright: 2-4mm Size in dark: 4-8mm

· If pupils are unequal, measure size in both dark and bright light

· To visualize dark irides, use:

o Burton lamp: hold ~25 cm (10in) from the patients and below the patient’s line of sight

o Ophthalmoscope: use as a dim flashlight to illuminate both eyes simultaneously (“light from below”)

§ Judge the roundness of each pupil and describe any abnormalities

§ Observe pupil’s response to light in dim illumination

· Note the magnitude of change (quantity) using scale 0-3

· Note the rapidity of reaction (quality) using slow (-) or fast (+)

· Expected findings

o Direct response of OD should equal direct response of OS

o Consensual response of OD should equal consensual response of OS

o Direct response of OD should equal consensual response of OD

§ Perform the swinging flashlight test

· Expected findings

o Rate and amount of constriction should be the same for both pupils

o Direct should equal consensual for both eyes

· If it is not the case for either eye: afferent pupillary defect in the eye with less constriction

§ Record using PERRLA (-) APD if all reflexes are normal

· PE: pupils equal

· R: round

· RL: reactive to light (direct and consensual)

· A: responsive to accommodation

· (-) APD: no APD

o Afferent pupil anomalies result in an APD

§ Severe retinal disease, optic nerve diseases or compromise, mass/lesion behind eye compressing optic nerve or chiasm

§ NOT with disorders of ocular media

§ Afferent pupillary defect (RAPD) indicates unilateral or asymmetric damage to the anterior visual pathways

· When the consensual response is greater than the direct response of one eye

· If present, pupils of both eyes will constrict less when the light is directed into the affected eye

o Both eyes will constrict when light beam directed into unaffected eye

· When light beam is directed in affected eye, causes less constriction in

o Affected eye: reduced direct reflex

o Unaffected eye: reduced consensual reflex

· Graded from trace to 4+

o 3-4+APD: immediate dilation of the pupil, instead of initial/equal constriction

o 1-2+APD: no change in pupil size immediately, followed by dilation

o Trace APD: initial constriction, but greater escape to a larger intermediate size than when light is swung back to normal eye

§ Amaurotic Pupil: severe or 4+APD

· Patients have an eye with “NLP”

· Light beam directed into affected eyeà no direct response in affected eye and no consensual response in unaffected

· Light beam directed into unaffected eyeà direct response in unaffected eye and consensual response in affected eye

· Near reflexes will be intact

Reverse (indirect) APD

· Performed when one pupil is fixed, dilated, or constricted

o ONLY observe the reactive pupil

· If APD in eye with reactive pupil, that pupil will constrict more with consensual stimulation than with direct

· If APD in eye with fixed pupil, the reactive pupil will constrict more with direct stimulation than with consensual

· Note reverse APD (implies you used a reverse technique)

o Efferent pupil anomalies: unilateral defects/lesions will often generate anisocoria

§ Anisocoria: usually 2-4 mm difference in dark and light

· If same degree of anisocoria in light and dark: physiologic

§ Big pupil problems: anisocoria greater under bright conditions due to a defect/lesion of the parasympathetic

· Adie’s tonic pupil

o Relatively common; primarily in females 20-40

o Presentation

§ Unilateral semi-dilated pupil

§ Pupil with minimal and slow reaction to light

§ Pupil with reduced direct, consensual (poor constriction of sphincter) and near responses to light

§ May present with a reduced near vision complaint

§ Vermiform motion of iris: quivering motion of iris at pupillary border due to segmental palsy of sphincter

§ 10-20% eventually affecting other eye

· Reduced direct response to light bilaterally

· Decreased near VA

· Prolonged pupil cycle time

o Etiology

§ Lesion of the parasympathetic pathway (ciliary ganglion) on the side of the pupil problem

§ Viral

o Diagnosis

§ 0.125% pilocarpine (wait 10-15 min)

· Constriction: Adie’s confirmed

· No constriction: either pharmacologic or 3^rd nerve

o Management

§ Rule other orbital and ocular conditions

§ Cosmesis

§ Accommodation

· Near add, sometimes unequal adds

· Equalize accommodation during refraction and other near or binocular testing

· Accommodation generally returns within 2 yrs

· Cranial Nerve Palsy

o Presentation

§ EOM paresis—exotropia and hypertropia (“down and out”) of eye affected

§ Ptosis

§ Fixed and dilated pupil, or non-reactive pupil

o Etiology

§ Pupil fibers are on the outside of CN III; they are involved early in a compressive lesion and are rarely involved in an ischemic infarction

§ Lesions that involve the pupil: tumor and aneurysm

§ Lesions that spare the pupil: vascular disease causing ischemia (diabetes, hypertension)

o Diagnosis

§ 0.125% pilocarpine—will NOT constrict

§ 1% pilocarpine—WILL constrict

o Management

§ Presentation of acute 3^rd nerve palsy with pupil involvement considered a medical emergency!

§ Manage diplopia and systemic cause of palsy

· Pharmacologic anisocoria: dilation of one eye

o Presentation

§ Usually unilateral, fixed and dilated pupil

§ Anticholinergic substances block the action of acetylcholine on the ciliary muscle and cause mydriasis

o Etiology

§ Scopolamine

§ Jimsonweed

§ Antihistamine drops

§ Atropine, homatropine, cyclopentalate

o Diagnosis

§ 0.125% pilocarpine—Will NOT constrict

§ 1% pilocarpine—Will NOT constrict

o Management

§ Reassurance and patient education

§ Little pupil problems: anisocoria is greater in dim conditions due to a defect/lesion to the sympathetic nervous system

· Horner’s syndrome

o Presentation

§ Miosis (can be mild: less than 1 mm of anisocoria)

§ Ptosis

§ Anhydrosis

***All on the same side as the lesion***

o Etiology

§ Interruption of the sympathetic system anywhere in its path

§ Congenital Horner’s: idiopathic or trauma at birth

· Heterochromia and anhydrosis

§ Central lesions: stroke, MS, spinal cord cancer, neck trauma

§ Preganglionic lesions: pancoast tumor, trauma, thyroid enlargement or lesion

§ Postganglionic lesions: extracranial or intracranial cause (Raeder’s, ICA dissection, complicated otitis media)

o Diagnosis

§ Look at old photographs

§ History of trauma, endardectomy, thyroidectomy?

§ Dilation lag test

· Take picture immediately after turning off lights and take another picture 15 seconds

· Horner’s pupil has a dilation lag in the dark of ~15 sec

§ 0.5% Apraclonidine (Iopidine) (wait 15-30 min)

· Dilates: confirms diagnosis of Horner’s

§ 10% Cocaine drop in affected pupil (wait 15 min)

· Does NOT dilate: confirms diagnosis of Horner’s

o Management

§ Important to determine before or after the bifurcation of the carotid artery

§ Differentiate by testing for anhydrosis (prism bar test and corn starch under heat lamp)

· Postganglionic lesions generally do not cause anhydrosis

· 1 % hydroxyamphetamine (done 48 hrs after cocaine test)

o Dilation: central or preganglionic lesion

o No dilation: postganglionic (“fail safe” affected pupil fails to dilate)

· Argyll-Robertson pupil

o Presentation

§ Bilaterally miotic, irregular pupils

§ Difficult to dilate

§ Direct and consensual responses absent or sluggish in affected eye(s)

§ DOES react to near (there is light-near dissociation)

o Etiology

§ Midbrain lesion

· Neurosyphilis or neuropathy from diabetes, alcoholism

· Pharmacologic anisocoria: constriction of one eye

o Cholinergic agents: pilocarpine (glaucoma drop) and physostigmine

o Near-Light Dissociation: pupils fail to respond to light, but near response intact

§ Afferent pathways interrupted, efferent pathways intact

§ Examples of conditions that manifest near-light dissociation

· Neurosyphilis: Argyll-Robertson pupil

· APD or amaurotic pupil

· Aberrant regenerations

o Pupil Irregularities

§ Aniridia: congenital absence of the iris (usually bilateral)

§ Iris coloboma (“keyhole” pupil)

· Usually involves the inferior nasal portion of the iris

· Wider at the pupillary margin than at the iris root

§ Corectopia: displaced pupil (frequently bilateral)

· May be displaced in any direction

§ Iridectomy: surgically created sector cut of the iris

§ Iris atrophy

· From age, inflammation, ischemia, trauma

· Iris holes may form creating polycoria

· May be sectoral (herpes zoster) or widespread

§ Iris cysts/tumors

· If extensive enough, may distort pupillary margins

§ Laser iridotomy: hole created in iris usually located superiorly at 10:00 or 12:00

· Shape of the pupil usually not affected

§ Persistent pupillary membrane (PPM): persistent embryolic structure

· Rarely affects pupillary movement

§ Trauma

· Tears of pupillary margin and sphincter

o Traumatic mydriasis and abnormal pupil light reflexes permanent

· Iridodialysis

o Tear at the iris root; D-shaped pupil

o Monocular diplopia may occur

§ Posterior synechia: attachment of iris to anterior lens surface from active or history of anterior uveitis or intraocular inflammation

§ Iridonesis: quivering of the iris

· Pupillary margins are irregular and reactivity will be reduced

· Seen in aphakic patients

o Pharmacologic dilation (bilateral)

§ Anticholinergics

§ Antihistamines

§ CNS depressants

§ Sympathomimetis and CNS stimulants (bind with alpha receptors on dilator muscle to cause mydriasis)

· Epinephrine, Cocaine, amphetamines

o Pharmacologic constriction (bilateral)

§ Barbituates

§ Opioids

§ Levodopa

§ Marijuana

§ Vitamin A

V EOM Testing

O Saccades

§ Rapid abrupt conjugate movement; stimulated by alternately fixating objects

§ Can be voluntary or reflex

O Pursuits (Versions)

§ Slower smooth conjugate movements; stimulated by target movements

§ Used to test binocular, conjugate movements of the eyes allowing the lines of sight (LOS) to move in a parallel direction (or fixed angle)

o EOM

§ Innervation

· CN VI (abducens): LR

· CN IV (trochlear): SO

· CN III (oculomotor): MR, SR, IR, IO

§ Planes of action

· LR and MR: horizontal plane

· SR and IR: vertical plane, 23-25° temporal

· SO and IO: vertical plane, 51-53° nasal

· Muscle paresis is most obvious when the LOS is directed to move the eye in the direction of its primary action within its plane of action

§ Synergistic muscles: muscles in same eye that assist in an action

§ Antagonistic muscles: muscles in same eye that have opposite actions

§ Yoked muscles: neurologically paired in opposite eyes

· Hering’s Law of Equal Innervation

o Procedure

§ Remove spectacles and use high illumination

§ Fixation target held ~40 cm from patient’s eyes

§ Instruct patient to follow light as its moved in “H” pattern

· Make sure you test to the extreme field of gaze (limit of the EOM)

§ Note any overactions (+) or underactions (-); perform ductions

§ Ductions are monocular eye movements into the 6 cardinal positions of gaze

· Identifies the faulty muscle(s)

· Can test each muscle in its field/plane of action

§ Parks 3-step used for hyper deviations to determine faulty muscle

§ Record EOM: full and smooth (F and S)

· FROM: full range of motion

· SAFE: smooth accurate full extent

** Also record if ductions=versions, etc**

V Stereopsis

o Stereopsis: the perception of 3-D visual space due to binocular disparity cues (disparities of the two retinal images)

o Stereoacuity: ability to discriminate very fine differences of objects in space by using binocular vision

§ Stereo acuity is not the same as depth perception

§ Must have some level of binocular vision to appreciate stereo acuity

§ Requires changes in both vergence and accommodation

o Monocular cues to depth perception must be learned

§ Retinal image size, linear perspective, texture density, luminance variations, aerial perspective, overlay, motion parallax, kinetic depth, myosensory cues from muscles controlling accommodation and convergence

o Each point on the retina has a local sign or directional value

§ Fovea: principal visual sign (straight ahead)

§ Corresponding retinal points: pairs of points in each eye that have the same local sign (point in one eye corresponds to an area in the other eye)

§ Objects that stimulate a pair of corresponding points appear to be single and located at the same position in space

o Stereo Tests Designs

§ Local stereopsis (line or contour)

· Targets have edges that are separated on background to produce disparity

· Smaller separation defines better stereopsis

· Howard Dolman Peg Test

o Thresholds stereopsis

o Most accurate

o Two types of testing: null threshold and JND

· Titmus Stereofly

o Linear polarized test

o 3 parts: “fly” for gross stereo (3,000’’), “animal” test (400’’-100’’), Wirt circles (800’’-40’’)

· Stereo Reindeer

Global stereopsis

· Matrix of black dots on gray background

· Lateral shift in central pattern

· NO monocular cues

· Random Dot

o Uses 3-D cross polarized spectacles

o Right side: 8 random dot figures-- 500 sec of arc on top and 250 sec of arc on bottom-----must identify which cell is empty

o Left side: modified circles (400’’ – 20’’), animals (400’’ – 100’’)

o Procedure

§ Present test perpendicular to LOS at a distance of 40 cm (16 in)**

§ Spectacles are placed over habitual

§ Score last number correct after 2 errors

§ Record sec of arc @ test distance, test used and note cc or sc

V Color Vision

o Three types of cones responsible for color vision

§ Each contain photopigments that maximally absorb different wavelengths

· Red (long), green (middle), blue (short)

o Defects

§ Protan: red wavelength (L cones)

§ Deutan: green wavelength (M cones)

§ Tritan: blue wavelength (S cones)

o Inherited color deficiencies

§ Anomalous trichromat (3 cone pigments)

· Protananolmalous: red weak

· Deutananolmalous: green weak

· Tritananolmalous: blue weak

§ Dichromat ( 2 cone pigments)

· Protanopia

· Deutanopia

· Tritanopia

§ Monochromat

· Rod

o True color blindness (may have few cones but abnormal in shape) and poor vision

· Cone

o Variation of color blindness (only one cone type present)

o Prevalence

§ Overall 4%

· Males 8%

o Protanomaly 1% Protanopia 1%

o Deuteranolamly 5% Deutranopia 1.1%

o Tritanopia 0.002%

· Females 0.5%

o Patient selection

§ Children at an early age

§ Patients at initial office visit

§ Unexplained decreased in VA

§ Report changes in color vision

§ Abnormal fundus findings

o Types of color vision tests

§ Color Naming

§ Color Mixing

· Anomaloscope

o Assess ability to make metameric matches

o Change mixture of monochromatic red and green

§ Color Confusion

· Pseudoisochromatic plates (PIC)

o Diagnostic plates: figure is isochromatic for one defect but not for another so it identifies type of deficiency

o Vanishing figure: normal sees, defective does not see

o Transformation: normal and defective see different figures

o Hidden digit/symbol: defective sees, normal does not see

o Screening mostly for inherited defects

· HRR

o Detects inherited and acquired defects

o Can be used on illiterate patients (symbols used)

· Ishihara

o Screen for inherited red/green anomalies

§ Color Matching (arrangement)

· Detects inherited or acquired

· Farnsworth D-15

o Quantifies depth of defect (mild/severe)

o Used only as diagnostic (not screener)

· Farnsworth-Munsell 100-Hue

o Good for detecting/classifying early acquired color deficiencies caused by ocular disease

o Detects subtle color discrimination

§ Occupational

· PIC, D-15, Farnsworth Lantern test (FALANT), ISCC Color Matching Aptitude test

o Procedure

§ Use “standard” illumination “C”

· MacBeth Easel Lamp

· Incandescent lighting inadequate

§ HRR

· Plates perpendicular to LOS at 75 cm

· Use correction unless tinted and test monocular!

· Ask patient how many symbols, what are they, and have trace where they are with brush

· Time limit: 20 sec/page

· Record check marks when correct for screening plates 5-10

o If ALL 6 correct: normal CV

o Only plate 5 or 6 missedà test plates 21-24: B/Y defect

o Only 1 or more plates 7-10 missedà test plates 11-20: R/G defect

§ Ishihara

· Plates perpendicular to LOS at 75 cm

· Use correction unless tinted and test monocular!

· Ask patient what do they see

· Time limit: 3 sec/plate

· Record number plates correct over number tested with pass/fail noted and the numbers said if missed

o Normal if 10/1l

o If </= 7 correct, test plates 12,13,14 to classify whether protan or deutan

§ Farnsworth D-15

· Caps should be 45 deg to patient’s LOS at 50 cm

· Use correction unless tinted and test monocular

· Instruct patient to place caps in chromatic order

· No time limit

**When recording, note the test used and if cc or sc**

o Management

§ Rod chromatism (poor VA and photophobia)

· Tinted lenses (red and amber) to obtain low scotopic luminance transmittance but decreased visibility in short wavelengths

§ Acquired defects should be directed to cause

§ Inherited defects: counseling, career limitations

V Cover Test

o Fusion: both eyes are looking at the same target at the same time

o Alignment

§ Orthophoria (ortho): “normal”, both eyes fixate on the same spot even after you break fusion

o Misalignment

§ Tropia (strabismus): manifest deviation of the line of sight of one eye

· The LOS of one eye is directed toward the object and the LOS of the other eye is directed elsewhere

· If the eye is misaligned outward it is called exotropia

o Will move in when the other eye is covered

· If the eye is misaligned inward it is called esotropia

o Will move out when the other eye is covered

· If the eye is misaligned upward it is called hypertropia

o Will move down when the other eye is covered

· If the eye is misaligned downward it is called hypotropia

o Will move up when the other eye is covered

§ Patient may have symptoms such as double vision, eye strain, headaches, fatigue, and reduced stereo

§ Phoria: latent deviation of the LOS

· Eye aligned except when fusion is disrupted

o Bruchner: observe the red reflex from the retina with the ophthalmoscope to detect leukocoria, strabismus, or anisometropia

o Hirschburg: use the transilluminator to find the corneal light reflex

§ To see 1 mm, patient must have 22 diopters

o Krimsky: perform Hirschburg and line up the corneal light reflex with prism

o Cover Test: objective test to determine the presence, amount, and direction of misalignment

§ Unilateral cover test (cover-uncover): detects tropia

§ Alternating cover test: to detect phoria and measure amount of tropia

o Procedure

§ Unilateral

· Distance: patient fixates on a letter that is one line larger than the best VA of the worst eye

· Near: patient uses a fixation stick with a small accommodative target

o Done at 40 cm or working distance

· Important to come from the nose

· Clinician covers OD and watches OS for movement; then covers OS and watches OD for movement

o Presence of movement indicates strabismus or tropia

§ Alternating

· Patient still fixates a target

· Clinician covers OD for 2 sec, then swings cover paddle from one eye to next

· Do NOT allow patient to view with both eyes at the same time

o Presence of movement on alternating but not on unilateral indicates phoria

o If there is movement on both unilateral and alternating, it is a tropia (tropia trumps a phoria)

o If there is no movement on both unilateral and alternating, check with 4 BI and 4 BO and there should be equal and opposite movements

o Measuring magnitude

§ Prisms deviate the image towards the apex

· ‘Exos’ need the image sent OUT---- use base IN

· ‘Esos’ need the image sent IN---- use base OUT

· ‘Hypers’ need the image sent UP---- use base DOWN

· ‘Hypos’ need the image sent DOWN---- use base UP

§ Procedure

· Put the prism behind the cover paddle and place in front of the eye at the same time

o For eso and exo, put prism in front of either eye

o For hyper and hypo, put prism in front of deviated eye

· Move occluder to other eye without allowing binocular fixation

· Increase prism amount without allowing binocular fixation until movement stops=neutrality

· Continue to increase amount until the direction of the movement reverses

· Record amount of prism that resulted in neutrality before reversal

o Recording

§ Orthophoria (lack of manifest or latent deviation)

· Horizontally ortho

· Vertically ortho

· Ortho both horizontally and vertically

§ Magnitude: prism diopters

§ Direction: exo (X), eso (E), hyper, hypo*

· Only name the hypo eye if it also has a horizontal constant tropia

§ Laterality: right (R), left (L), alternating (A)

· Note the fixation preference

§ Frequency: constant (C) or intermittent (I)

· If intermittent, write down percentage

§ Nature: comitant or incomitant

· Use 9-gaze test or Park’s 3-step test

§ Also note: Testing distance, cc or sc

§ Normal: Distance 1 XP + 2 Near 3 XP + 3

§

o Duane’s Classifications

§ Basic: <8 Δ difference between distance and near

§ Distance vs. Near Deviations

· Convergence Insufficiency

o Exo at near > distance

· Convergence Excess

o Eso at near > distance

· Divergence Insufficiency

o Eso at distance > near

· Divergence Excess

o Exo at distance > near

V Blood Pressure

o Important to do routine BP measurements:

§ Elevated blood pressure increase the risk of coronary heart disease, stroke, and kidney failure

§ “Silent killer” since you cannot tell by the way you feel

§ Patients will often seek eye care before other health care

§ HTN can result in significant visual morbidity

o Risk Factors for HTN

§ Smoking, high cholesterol, obesity, diabetes, age (elderly), family history, race (African-Americans), gender (male) and stress

o Systolic pressure: ventricular contraction

o Diastolic pressure: ventricular relaxation

O Korotkoff Sounds

§ Phase 1: appearance of clear taping sounds (systolic)

§ Phase 2: swishing of sounds

§ Phase 3: increase clear sounds, increase intensity

§ Phase 4: abrupt muffling of sounds (diastolic I)

§ Phase 5: complete disappearance of sound (diastolic II)

§ Auscultatory gap: early, temporary disappearance of sound between phase 1 and 2 that can cause serious underestimation of systolic (or overestimation of diastolic pressure)

o Procedure

§ Patient should be seated and relaxed with legs uncrossed

§ Patient’s arm should be slightly bent, resting on the arm rest with palm up and unrestricted baring of arm

§ Palpate for systolic pressure

· Place cuff ~1’’ above antecubital crease

· Palpate the radial artery at wrist using fore finger and middle finger

· Inflate cuff to ~30mmHg above level at which the pulse disappears

· Note reading and deflate cuff

§ Place diaphragm over brachial artery between the crease and the lower edge of the cuff

§ Inflate cuff to 30 mmHg above systolic (determined by palpation)

§ Deflate at a rate of 2-3 mmHg/sec

§ Listen for phase 1 sound (regular tapping sound)

· Note reading: systolic pressure

§ Continue deflation and listen for phase 5 (complete disappearance of sound)

· Note reading: diastolic pressure

§ If sounds are too weak, ask patient to open and clench fist ~10x or inflate cuff quickly

· Repeated inflation will cause venous engorgement and decrease sounds

§ Deflate cuff and remove

§ Record: systolic/ diastolic, arm used, posture, time of day, and cuff size if other than regular

o Sources of Error

§ Falsely High

· Brachial artery below heart level

· Asucultatory gap (diastolic)

· Cuff too small

· Anxiety or fear

· Isolated sources: anxiety, stress, recent exertion, pain, caffeine

§ Falsely Low

· Brachial artery above heart level

· Asucultatory gap (systolic)

· Cuff too large

· Deflating too rapidly

Hypertension Classification

Referral Guidelines

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