b. Diagnostic Evaluation.docx

7/25/2019 b. Diagnostic Evaluation.docx

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Diagnostic Evaluation DIRECT OPHTHALMOSCOPY A direct ophthaloscope is a hand!held

instruent "ith various plus and inus lenses# The lenses can $e rotated into place% ena$ling the

e&ainer to $ring the cornea% lens% and retina into 'ocus se(uentiall)# The e&ainer holds theophthaloscope in the right hand and uses the right e)e to e&aine the patient*s right e)e# The

e&ainer s"itches to the le't hand and le't e)e "hen e&aining the patient*s le't e)e# During this

e&aination% the roo should $e dar+ened% and the patient*s e)e should $e on the sae level as

the e&ainer*s e)e# The patient and the e&ainer should $e co'orta$le% and $oth should $reathenorall)# The patient is given a target to ga,e on and is encouraged to +eep $oth e)es open and

stead)# -hen the 'undus is e&ained% the vasculature coes into 'ocus 'irst# The veins are larger

in diaeter than the arteries# The e&ainer should 'ocus on a large vessel and then 'ollo" itto"ard the idline o' the $od)% "hich leads to the optic nerve# The central depression in the disc

is +no"n as the cup# The noral cup is a$out one third o' the disc# The si,e o' the ph)siologic

optic cup should $e estiated# Are the disc argins sharp% or are the) $lurred. Do the veins have a

silver) or copper) appearance. The peripher) o' the retina can $e e&ained $) having the patientshi't his or her ga,e# The last area o' the 'undus to $e e&ained should $e the acula% $ecause this

area is the ost light sensitive# The retina o' a )oung person o'ten has a glistening e''ect% "hich is

soeties re'erred to as a cellophane re'le The health) 'undus should $e 'ree o' an) lesions#The e&ainer should loo+ 'or intraretinal heorrhages% "hich a) appear as red sudges or% i'

the patient has h)pertension% a) loo+ soe"hat'lae shaped# Lipid a) $e present in the retinao' patients "ith h)percholesteroleia or dia$etes# This lipid has a )ello"ish appearance# So't

e&udates that have a 'u,,)% "hite appearance /ie% cotton!"ool spots0 should $e noted# Thee&ainer loo+s 'or icroaneur)ss% "hich loo+ li+e little red dots% and nevi# Drusen /ie% sall%

h)aline% glo$ular gro"ths0% coonl) 'ound in acular degeneration% appear to $e )ello"ish

areas "ith indistinct edges# Sall drusen have a ore distinct edge# The e&ainer should s+etchthe 'undus and docuent an) a$noralities# I1DIRECT OPHTHALMOSCOPY The indirect

ophthaloscope is an instruent coonl) used $) the ophthalologist# It produces a $right and

intense light# The light source is a''i&ed "ith a pair o' $inocular lenses% "hich are ounted on the

e&ainer*s head# The ophthaloscope is used "ith a hand!held% 23!diopter lens# This instruentena$les the e&ainer to see larger areas o' the retina% although in an unagni'ied state# SLIT!

LAMP E4AMI1ATIO1 The slit lap is a $inocular icroscope ounted on a ta$le# This

instruent ena$les the user to e&aine the e)e "ith agni'ication o' 53 to 63 ties the realiage# The illuination can $e varied 'ro a $road to a narro" $ea o' light 'or di''erent parts o'

the e)e# 7or e&aple% $) var)ing the "idth and intensit) o' the light% the anterior cha$er can $e

e&ained 'or signs o' in'laation# Cataracts a) $e evaluated $) changing the angle o' the

light# -hen a hand!held contact lens% such as a three!irror lens% is used "ith the slit lap% theangle o' the anterior cha$er a) $e e&ained% as a) the ocular 'undus#

COLOR 8ISIO1 TESTI19 The a$ilit) to di''erentiate colors has a draatic e''ect on theactivities o' dail) living# 7or e&aple% the ina$ilit) to di''erentiate $et"een red and green can

coproise tra''ic sa'et)# Soe careers /eg% coercial art% color photograph)% airline pilot%

electrician0 a) $e closed to people "ith signi'icant color de'iciencies# The photoreceptor cells

responsi$le 'or color vision are the cones% and the greatest area o' color sensitivit) is in theacula% the area o' densest cone concentration# A screening test% such as the pol)chroatic plates

discussed in the ne&t paragraph% can $e used to esta$lish "hether a person*s color vision is "ithin

noral range# Color vision de'icits can $e inherited# 7or e&aple% red:green color de'iciencies areinherited in an 4!lin+ed anner% a''ecting appro&iatel) ;< o' en and 3#6< o' "oen#

Ac(uired color vision losses a) $e caused $) edications /eg% digitalis to&icit)0 or patholog)

such as cataracts# A siple test% such as as+ing a patient i' the red top on a $ottle o' e)e drops

appears redder to one e)e than the other% can $e an e''ective tool# Changes in the appreciation o'the gradations o' the color red can indicate acular or optic nerve disease# =ecause alteration in

color vision is soeties indicative o' conditions o' the optic nerve% color vision testing is o'ten

per'ored in a neuro!ophthalologic "or+up# The ost coon color vision test is per'oredusing Ishihara pol)chroatic plates# These plates are $ound together in a $oo+let# On each plate o'

this $oo+let are dots o' priar) colors that are integrated into a $ac+ground o' secondar) colors#

The dots are arranged in siple patterns% such as nu$ers or geoetric shapes# Patients "ith

diinished color vision a) $e una$le to identi') the hidden shapes# Patients "ith central visionconditions /eg% acular degeneration0 have ore di''icult) identi')ing colors than those "ith


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peripheral vision conditions /eg% glaucoa0 $ecause central vision identi'ies color# AMSLER

9RID The Asler grid is a test o'ten used 'or patients "ith acular pro$les% such as acular

degeneration# It consists o' a geoetric grid o' identical s(uares "ith a central 'i&ation point# Thegrid should $e vie"ed $) the patient "earing noral reading glasses# Each e)e is tested

separatel)# The patient is instructed to stare at the central 'i&ation spot on the grid and report an)

distortion in the s(uares o' the grid itsel'# 7or patients "ith acular pro$les% soe o' the s(uares

a) loo+ 'aded% or the lines a) $e "av)# Patients "ith age!related acular degeneration arecoonl) given these Asler grids to ta+e hoe# The patient is encouraged to chec+ the

're(uentl)% as o'ten as dail)% to detect an) earl) signs o' distortion that a) indicate the

developent o' a neovascular choroidal e$rane% an advanced stage o' acular degenerationcharacteri,ed $) the gro"th o' a$noral choroidal vessels# >LTRASO1O9RAPHY Lesions in

the glo$e or the or$it a) not $e directl) visi$le and are evaluated $) ultrasonograph)# A pro$e

placed against the e)e ais the $ea o' sound# High!'re(uenc) sound "aves eitted 'ro a

special transitter are $ounced $ac+ 'ro the lesion and collected $) a receiver that apli'ies anddispla)s the sound "aves on a special screen# >ltrasonograph) can $e used to identi') or$ital

tuors% retinal detachent% and changes in tissue coposition# 7undus photograph) is a techni(ue

used to detect and docuent retinal lesions# The patient*s pupils are "idel) dilated during theprocedure% and visual acuit) is diinished 'or a$out ?3 inutes due to retinal @$leaching $) the

intense 'lashing lights# 7L>ORESCEI1 A19IO9RAPHY 7luorescein angiograph) evaluatesclinicall) signi'icant acular edea% docuents acular capillar) nonper'usion% and identi' ies

retinal and choroidal neovasculari,ation/ie% gro"th o' a$noral ne" $lood vessels0 in age!relatedacular degeneration# It is an invasive procedure in "hich 'luorescein d)e is inBected% usuall) into

an antecu$ital area vein# -ithin 53 to 5 seconds% this d)e can $e seen coursing through the retinal

vessels# Over a 53!inute period% serial $lac+!and!"hite photographs are ta+en o' the retinalvasculature# The d)e a) ipart a gold tone to the s+in o' soe patients% and urine a) turn deep

)ello" or orange# This discoloration usuall) disappears in 26 hours# TO1OMETRY Tonoetr)

easures IOP $) deterining the aount o' 'orce necessar) to indent or 'latten /applanate0 a

sall anterior area o' the glo$e o' the e)e# The principle involved is that a so't e)e is dented oreeasil) than a hard e)e# Pressure is easured in illieters o' ercur) / Hg0# High readings

indicate high pressure lo" readings% lo" pressure# The three ost coon t)pes o' tonoeters

are indentation% applanation% and noncontact# The procedure is noninvasive and is usuall) painless#A topical anesthetic e)e drop is instilled in the lo"er conBunctival sac% and the tonoeter is then

used to easure the IOP# 9O1IOSCOPY 9onioscop) visuali,es the angle o' the anterior cha$er

to identi') a$noralities in appearance and easureents# The gonioscope uses a re'racting lens

that can $e a direct or indirect lens# The indirect lens vie"s the irror iage o' the oppositeanterior cha$er angle and can $e used onl) "ith a slit lap# The direct gonioscopic lens gives a

direct vie" o' the angle and its structures# PERIMETRY TESTI19 Perietr) testing evaluates the

'ield o' vision# A visual 'ield is the area or e&tent o' ph)sical space visi$le to an e)e in a givenposition# Its average e&tent is degrees up"ard% F degrees do"n"ard% 3 degrees in"ard% and

G degrees out"ard "hen the e)e is in the priar) ga,e /ie% loo+ing directl) 'or"ard0# It is a

threediensional contour representing areas o' relative retinal sensitivit)# 8isual acuit) is sharpest

at the ver) top o' the 'ield and declines progressivel) to"ard the peripher)# 8isual 'ield testing /ie%perietr)0 helps to identi') "hich parts o' the patient*s central and peripheral visual 'ields have

use'ul vision# It is ost help'ul in detecting central scotoas/ie% $lind areas in the visual ' ield0 in

acular degeneration and the peripheral 'ield de'ects in glaucoa and retinitis pigentosa# Thet"o ethods o' perietric testing are anual and autoated perietr)# Manual perietr)

involves the use o' oving /+inetic0 or stationar) /static0 stiuli or targets# An e&aple o' +inetic

anual perietr) is the tangent screen# A tangent screen is a $lac+ 'elt aterial ounted on a "all

that has a series o' concentric circles dissected $) straight lines eanating 'ro the center# It teststhe central ?3 degrees o' the visual 'ield# Autoated perietr) uses stationar) targets% "hich are

harder to detect than oving targets# In this test% a coputer proBects light randol) in di''erent

areas o' a hollo" doe "hile the patient loo+s through a telescopic opening and depresses a$utton "henever he or she detects the light stiulus# Autoated perietr) is ore accurate than

anual perietr)# Ipaired 8ision RE7RACTI8E ERRORS In re'ractive errors% vision is

ipaired $ecause a shortened or elongated e)e$all prevents light ra)s 'ro 'ocusing sharpl) on

the retina# =lurred vision 'ro re'ractive error can $e corrected "ith e)eglasses or contact lenses#The appropriate e)eglass or contact lens is deterined $) re'raction# Re'raction ophthalolog)


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consists o' placing various t)pes o' lenses in 'ront o' the patient*s e)es to deterine "hich lens

$est iproves the patient*s vision# The depth o' the e)e$all is iportant in deterining re'ractive

error /7ig# ;!0# Patients 'or "ho the visual iage 'ocuses precisel) on the acula and "ho donot need e)eglasses or contact lenses are said to have eetropia/noral vision0# People "ho

have)opiaare said to $e nearsighted# The) have deeper e)e$alls the distant visual iage 'ocuses

in 'ront o'% or short o'% the retina# M)opic people e&perience $lurred distance vision# -hen people

have a shorter depth to their e)es% the visual iage 'ocuses $e)ond the retina the e)es areshallo"er and are called h)peropic# People "ith h)peropiaare 'arsighted# These patients

e&perience near vision $lurriness% "hereas their distance vision is e&cellent# Another iportant

cause o' re'ractive error is astigatis% an irregularit) in the curve o' the cornea# =ecauseastigatis causesa distortion o' the visual iage% acuit) o' distance and near vision can $e

decreased# E)eglasses "ith a c)linder correction or rigid or so't toric contact lenses are

appropriate 'or these patients# LO- 8ISIO1 A1D =LI1D1ESS Lo" visionis a general ter

descri$ing visual ipairent that re(uires patients to use devices and strategies in addition tocorrective lenses to per'or visual tas+s# Lo" vision is de'ined as a $est corrected visual acuit)

/=C8A0 o' 23:F3 to 23:233 /Ta$le ;!50# =lindnessis de'ined as a =C8A o' 23:633 to no light

perception# The clinical de'inition o' a$solute $lindness is the a$sence o' light perception# Legal$lindness is a condition o' ipaired vision in "hich an individual has a =C8A that does not

e&ceed 23:233 in the $etter e)e or "hose "idest visual 'ield diaeter is 23 degrees or less# Thisde'inition does not e(uate "ith 'unctional a$ilit)% nor does it classi') the degrees o' visual

ipairent# Legal $lindness ranges 'ro an ina$ilit) to perceive light to having soe visionreaining# An individual "ho eets the criteria 'or legal $lindness a) o$tain governent

'inancial assistance# There are ore than 5%36%333 legall) $lind Aericans "ho are 63 )ears o'

age or older# A'rican Aericans have a higher rate o' $lindness than do Caucasians /Preshel Prevent =lindness Aerica% 23320# Ipaired vision is accopanied $) di''icult) in per'oring

'unctional activities# Individuals "ith visual acuit) o' 23:;3 to 23:533 "ith a visual 'ield

restriction o' 3 degrees to greater than 23 degrees can read at a nearl) noral level "ith optical

aids# Their visual orientation is near noral $ut re(uires increased scanning o' the environent/ie% s)steatic use o' head and e)e oveents0# In a visual acuit) range o' 23:233 to 23:633 "ith

a 23!degree to greater than 53!degree visual 'ield restriction% the individual can read slo"l) "ith

optical aids# His or her visual

orientation is slo"% "ith constant scanning o' the environent individuals in this categor) have

travel vision# Individuals "ith hand otion vision or no vision a) $ene'it 'ro the use o'

o$ilit) devices /eg% cane% guide dog0 and should $e encouraged to learn =raille and to usecoputer aids# The ost coon causes o' $lindness and visual ipairent aong adults 63

)ears o' age or older are dia$etic retinopath)% acular degeneration% glaucoa% and cataracts%

/Preshel Prevent =lindness Aerica% 23320# Macular degeneration is ore prevalent aongCaucasians% "hereas glaucoa is ore prevalent aong A'rican Aericans# Age!related changes

in the e)e are descri$ed in Ta$le ;!2# Lo"!8ision Assessent The assessent o' lo" vision

includes a thorough histor) and the e&aination o' distance and near visual acuit)% visual 'ield%

contrast sensitivit)% glare% color perception% and re'raction# Speciall) designed% lo"!vision visualacuit) charts are used to evaluate patients# PATIE1T I1TER8IE- During histor) ta+ing% the

cause and duration o' the patient*s visual ipairent are identi'ied# Patients "ith retinitis

pigentosa% 'or e&aple% have a genetic a$noralit)# Patients "ith dia$etic acular edeat)picall) have 'luctuating visual acuit)# Patients "ith acular degeneration have central acuit)

pro$les# Central acuit) pro$les cause di''icult) in per'oring activities that re(uire 'iner

vision% such as reading# People "ith peripheral 'ield de'ects have ore di''iculties "ith o$ilit)#

The patient*s custoar) activities o' dail) living% edication regien% ha$its /eg% so+ing0%acceptance o' the ph)sical liitations $rought a$out $) the visual ipairent% and realistic

e&pectations o' lo"!vision aids ust also $e identi'ied# These aspects o' the patient*s activities are

iportant indicators 'or planning care that "ill include guidelines 'or sa'et) and re'errals to socialservices#

assessent

Contrast!sensitivit) testing easures visual acuit) in di''erent degrees o' contrast# The initial testa) ta+e the 'or o' sipl) turning on the lights "hile testing the distance acuit)# I' the patient


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coprehend spatial concepts# The goal o' orientation and o$ilit) training is to 'oster

independence in the environent# Training a) $e accoplished $) using auditor) and tactile

cues and $) providing anticipator) in'oration# Having a concept o' the spatial coposition o' theenvironent /ie% cognitive ap0 enhances independence o' those "ho are $lind# Orientation and

o$ilit) training progras are o''ered $) counit) agencies serving the $lind or visuall)

ipaired# Training includes using o$ilit) devices 'or travel% the long cane% electronic travel aids%

dog guides% and orientation aids# The $asic orientation and o$ilit) techni(ues used $) a sightedperson to assist a person "ho is $lind or visuall) ipaired to a$ulate sa'el) and e''icientl) are

called sighted!guide techni(ues# Spatial Orientation and Mo$ilit) in Institutional Settings#A $lind

or severel) visuall) ipaired patient re(uires strategies 'or adapting to the environent# Theonocular postoperative patient "hose 'unctioning e)e is restricted $) a surgical patch or $)

postoperative in'laation re(uires earl) a$ulation Bust li+e an) postoperative patient# The

activities o' dail) living% such as "al+ing to a chair 'ro a $ed% re(uire spatial concepts# The

patient needs to +no" "here he or she is in relation to the rest o' the roo% to understand thechanges that a) occur% and ho" to approach the desired location sa'el)# This re(uires a

colla$orative e''ort $et"een the patient and the nurse% "ho serves as the sighted guide# Patients

"hose visual ipairent results 'ro a chronic progressive e)e disorder% such as glaucoa% have$etter cognitive apping s+ills than the suddenl) $linded patient# The) have developed the use o'

spatial and topographic concepts earl) and graduall) hence% ree$ering a roo la)out is easier'or the# Suddenl) $linded patients have ore di''icult) in adBusting and eotional and

$ehavioral issues o' coping "ith $lindness a) hinder their learning# These patients re(uireintensive eotional support# The nurse ust assess the degree o' ph)sical assistance the patient

"ith a visual de'icit re(uires and counicate this to other health care personnel# The 'ood tra)*s

coposition is li+ened to the 'ace o' a cloc+# 7or e&aple% the ain plate a) $e descri$ed as$eing at 52 o*cloc+ or the co''ee cup at ? o*cloc+# In the hospital% the $edside ta$le and the call

$utton ust al"a)s $e "ithin reach# The parts o' the call $utton are e&plained% and the patient is

encouraged to touch and press the $uttons or dials until the activit) is astered# The patient ust

$e 'ailiari,ed "ith the location o' the telephone% "ater pitcher% and other o$Bects on the $edsideta$le# All articles and 'urniture ust $e replaced in the sae positions# Introducing onesel' on

entering a patient*s roo is al"a)s a polite gesture and helps in the orientation o' a $lind patient#

The nurse should $e a"are o' the iportance o' techni(ue in providing ph)sical assistance%developing independence% and ensuring sa'et)# The readiness o' the patient and his or her 'ail) to

learn ust $e assessed $e'ore initiating orientation and o$ilit) training#

PROMOTI19 HOME A1D COMM>1ITY!=ASED CARE Teaching Patients Sel'!Care#Thenurse% social "or+ers% 'ail)% and others colla$orate to assess the patient*s hoe condition and

support s)ste# I' availa$le% a lo"!vision specialist should $e consulted $e'ore discharge%

particularl) 'or patients 'or "ho identi')ing and adinistering edications pose pro$les# Thelevel o' visual acuit) and patient pre'erence help to deterine appropriate interventions# 7or

e&aple% a plastic pill container "ith dividers that has $een pre'illed "ith a "ee+*s suppl) o'

edication can a+e edication adinistration easier 'or soe patients% "hereas others a)

pre'er to have edication $ottles ar+ed "ith te&tured paints# Man) patients re(uire re'erral tosocial services# Patients "ith ha$its that a) Beopardi,e sa'et)% such as so+ing% need to $e

cautioned and assisted to a+e their environent sa'e# Counit) Progras and Services#In the

>nited States% la"s such as the Reha$ilitation Act% the Civil Rights Act% and the Aericans -ithDisa$ilities Act support assistance o' the $lind# 9overnental services include incoe assistance

through Social Securit) Disa$ilit) Incoe and Suppleental Securit) Incoe health insurance

through Medicaid and Medicare progras support services% such as vocational reha$ilitation

progras o''ered $) the Division o' =lind Services ta& e&eptions and ta& deductionsDepartent o' 8eterans A''airs progras 'or visuall) ipaired veterans and >#S# Postal Service

reduced postage 'or =raille aterials and tal+ing $oo+s# Soe private and nonpro'it services are

identi'ied in @Resources and -e$sites at the end o' this chapter#

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