dolhyancha takta

dolhyancha takta kinwa optotype haah eka takta aahe joou drushya tikshnata vyaktinishthapane mojanyasathi vaparla jaato. drushtidosh asalelya vyaktinchi tapasani karnyasathi netramapak, doctor kinwa paricharika yansarkhya aarogya seva vyavsayikandvare dolhyanche takte anekada vaparale jaatat. netratadnya, jeey dolhyamadhye tadnya aahet, teey dekhil aushadhe kinwa shastrakriya yasarkhya vividh upcharanna pratisad mhanoon tyanchya rugnanchya drushya tikshnatevar laksh thevanyasathi dolhyanche takte vapartat.
jyaa vyaktichya drushtichi chachani kelee jaat aahe tyaa vyaktipasoon pramanit antaravar takta thewala jaato. tyanantar tee vyakti taktyavaril chinhe olakhanyacha prayatna karate, mothya chinhanpasun suruvat karate aanee tee vyakti chinhe olakhoo shakat nahee toparyant haloohaloo lahan chinhansah suru rahate. vishvasarhpane olakhali jaau shakanari sarvat lahan chinhe hii tyaa vyaktichi drushya tikshnata manali jaatat.
snellen chart sarvat jaast vaparla jaato. paryayi prakarchya netra taktyanmadhye logmar takta, landolt see, eae takta, lii chachani, golovin-sivatsev takta, rosenbaum takta aanee jegger takta yancha samavesh hoto. aadhi namood kelyapramane, dolhyanche takte drushya tikshnata mojatat. dolhyanche takte doctoranna kachbindu, drushtipatalatil samasya kinwa paridhiy drushti gamavane yasarkhya dolhyanchya aajaranchi mahitee dett naheet. 
vyavharat, duochrom chachani vaparoon nikal punha tapasane khoop mahatvache aahe, kaaran yamule apavartan antim goal sudharu shakato. snellen chartmadhye, visheshtah chashmyapeksha vegale vagoo vagoo toric contact lensasathi, paripoorn durbini drushti asanyapeksha tee chachani uttirn hone adhik mahatvache aahe. anyatha durbini sanlayan heey apekshit asalelyapeksha white asoo shakate.
itihas.
drushti sudharanyasathi dolhyanche chashma vaparanyachi sankalpana teravya shatkachya uttaradhapasun prachalit aahe. vidnyan haloohaloo sudharat asatana, netravidnyan kshetratil cornelius donders sarkhya pratishthit doctoranni rugnachya drushtiche kalatit dosh sudharanyasathi kaay kele pahije yabaddal spasht vyakhya denyas suruvat kelee. rugnachya kamatoon fayda honyasathi hii prakriya kaay hotee heey haloohaloo spasht jhaale asale taree, aekhadyachya drushtitil dosh siddha karnyasathi konatihi eksaman tapasani kelee gelee nahee. yaa kalat netravidnyan kshetratil dnyan prachand vadhale. 
mageel abhyasanmule doctoranni (jagbharat) drushti tikshnatechi tapasani karnyacha marg nishchit keela. german netra chikitsak, heinrich kuhler yanni druk tikshnatechi chachani ghenyasathi pahili tapasani prastavit kelee. tyanantar thodyach velat, edward jegger yaa austriyan doctorane eka takta tayar keela jyane drushtichya tikshnatechi chachani kelee. jaree dolhyanchya taktyachi samanya sankalpana 1830 chya dashakat aadhi namood kelelya doctoranni sadar kelee asali, taree tyaa velee drushya tikshnatechi chachani karnyasathi sarvat prabhavi takta 1862 madhye dutch netratadnya herman snellen yanni parishkrut keela. snellen haah dondercha pahila sahayyak jhaala tevha tyachya taktyachi sankalpana suru jhaali. snellen yanni dow. tyanni rugnanna bhintivaril takta pahoon tyanchya drushtidoshanche nirdharan kele tevha teey aswasth jhaale. sharirshastrasarkhya vidnyanachya itar shakhanmadhye too khoop vyagra asalyamule, dondersney akheris snellen karnyachya aaplya aaplya sopavalya. 
donderschee prasiddhi aanee netravidnyan kshetraprati snelanchya naisargik pratibhemule, anek doctoranna utrectmadhye tyanchya kalpana samayik karnyasathi bhet denyache aamish dakhavanyat aale. tyachya saravadarmyan jawalun kaam karat asatana, snelanane swatacha takta tayar keela joou drushya tikshnata mojato. snelancha dolhyancha takta haah tyachya prakaratil pahila banala, mhanoon tyaa kalat drushtiche antar tapasanyasathi hii sarvat vaidnyanikdrushtya vishvasarh rachana aahe. snelanche tyachya taktyanmadhye yash heey hote qee teey drushya tikshnata tikshnata mageel modelpeksha vegale hote. tyachya taktyat uttejananchya aakarat farak hota. snelanchya netrapattikene drushya tikshnatechya chachaniche darvaje ughadale, tyamule teey jaagtik manak banale. 
yaa taktyala sarvatra mothee magani hotee. snelanchya khalee abhyas abhyas japani netratadnya eema tenko yannihi japanmadhye vaparla jaanara dolhyancha takta tayar keela. dolhyanche takte tayar jhalyamule, mulanchya dolhyanchi chachani ghenyasathi shalanmadhye drushti tapasani (andaje 1899 madhye suru) sarkhya chachanya ghenyat aalya. dolhyancha takta paribhashit karoo shakanari dusari sandnya, optotype, hii pramanit drushtichi chachani ghenyasathi sarvat samanya pariksha aahe.
prakriya.
takte drushtipatalanchya anek ranga darshavtat, jee drushti chachanisathi pramanit chinhe aahet. optotypes heey sahasa akshare, sankhya kinwa bhaumitik chinhe asatat. taktyachya pratyek panktit vegvegalya aakarache optotype darshavile aahet. samanyatah sarvat mothe optotype varchya ranget asatat. taktachya talashi optotype haloohaloo lahan hotat.
tee vyakti konatehi chashma kinwa contact lains kadhoon takte aanee taktyapasoon pramanit antaravar ubhi rahate kinwa basate (udaa.jee., snellen chartsathi 20 phoot). tyanantar tyaa vyaktila taktyavaril optotypes olakhanyas sangitale jaate, mothya panktinpasoon suru houn joparyant optotypes yapudhe vishvasarhpane olakhale jaau shakat naheet toparyant lahan panktinparyant suru thevanyas sangitale jaate. jyaa ranget vyakti chinhe vishvasarhpane olakhoo shakate tee drushya tikshnata paribhashit karate.
eka velee eka dolhyachi chachani kelee jaate. vyavharikdrushtya, haah dusra dolha hatane, kagadachya tukadyane kinwa chhotya paddlene zakoon sadhya keela jaato. chashma kinwa contact lensshivay chachani kelyanantar, lagoo asalyas, tee vyakti tee paridhan karat asatana chachani punha kelee jaate. anekada, asha apavartak lenscha vapar kelyane drushya tikshnata samanya hoil. pinhole aucluder vaparoon apavartak truti sudharali jaau shakate. pinholechya vaparane jarr drushya tikshnata sudharali tarr drushya tikshnata sudharanyasathi apavartak lenscha vapar keela jaau shakato. squinting pinhole aukludarsarkhach parinam sadhya karoo shakate.
snellen charts, drushya tikshnata anshamadhye (varchya kramankat) 20 aanee vibhajkamadhye (khalchya kramankat) 10 teey 600 paryantchya moolyansah apurnank mhanoon nondavali jaate. chhed haah payanmadhil antar darshavito jyavar samanya drushti asaleli vyakti chachani kelelya vyaktine olakhaleli samaan chinhe yogyaritya olakhanyasathi ubhe rahoo shakate. udaharanarth, 20/20 chee drushya tikshnata samanya manali jaate.
vividhata.
dolhyanche takte anek prakarche aahet aanee teey vividh paristhitinmadhye vaparale jaatat. udaharanarth, snellen chart 6 meater kinwa 20 footanvar vaparnyasathi tayar keela gela aahe aanee tyamule durchya drushtichya chachanisathi yogya aahe, tarr eae. dii. dii. aar. ess. chart 4 meterver vaparnyasathi tayar keela gela aahe. jawalpasachya kinwa vyavsayik kamanmadhye (jase qee vachan kinwa sanganakacha vapar) ekhadya vishayachi drushti tapasanyachi dekhil anekada garaj asate. yaa paristhitinsathi, rosenbaum chart kinwa jegger chart vaparla jaau shakato.
snellen chart purvanirdharit rahila asala taree, kahee lekhakanni assa yuktivad keela aahe qee logmar chart shreshth aahe. logmar chart pratyek olivar samaan sankhyene chinhe sadar karato, vividh aakaranmadhye samanpane supathya asalelya aksharansah eka aksharshail vaparato aanee chinhacha aakar laghuganakinusar badaloon, manak nasalelya antaravar vaparane sope aahe. yaa sudharanancha parinam mhanoon, drushya tikshnata mojanyasathi logmar chart adhik vishvasarh sadhan mhanoon prastavit karnyat aala aahe.
arbhake, lahan mule aanee ashikshit praudhanmadhye drushtichi tikshnata mojane katheen asoo shakate. lii chinhansarkhe vishesh netra takte vaparale jaau shakatat. eka aavruttit sadhee chitre kinwa namune vaparale jaatat. itar 'eae' heey block akshar vegvegalya dishene valavoon chhapale jaatat, tathakathit 'eae'. pratyek 'eae' konatya dishene jaat aahe heey rugna fakt soochit karato. landolt see chart samaan aaheh ranganmadhye vegvegalya vibhagansah vartule gahal asatat aanee chachani ghenara pratyek tutalela tukada kuthe aahe yache varnan karato. shevatchya done prakarchya taktyanmule rugnachya pratimancha andaj lagnyachi shakyata dekhil qamee hote.
dolhyanchi kalji kalji vyavsayikanchi aavashyakta asalelya drushtichya sambhavya samasya olakhanyasathi palak aanee kalji ghenare tyanchya mulachya drushtichi chachani gharatoon karoo shakatat. teen aanee tyahoon adhik vayachya mulachi chachani 'pointing game' khelanyasathi tumbling eae chartcha vapar karoon purn kelee jaau shakate. yaa chachanisathi, mool taktyapasoon 10 phoot antaravar eka khurchivar basate, eka dolhyavar haluvarpane dolha zakoon thevate. palak kinwa kalji ghenara pratyek eae kadey nirdesh karato, jyachi suruvat sarvat mothya eae pasoon hote. mug mool eae jyaa dishene aahe tyaa dishene nirdesh karate (varr, khalee, davikade, ujavikade). mulane olakhali asaleli eae. ess. asaleli sarvat lahan resha nondavali jaau shakate. eae laa laa vividh dishanirdeshancha gharee chachani karnyapurvi mulasobat aadhava ghetala pahije. vyavsayik netratadnyanni ghetalelya parikshanitake gharguti chachanya achook nasatat. gharguti netra chachanyanni vyavsayik netrachikitsakakade bhet denyachya jaagi gheu naye.
paryay.
dolhyanchya taktyasathi sanganak-aadharit paryay vikasit kele gele aahet, parantu uchch pradarshan resolution aanee dii. pii. aay. lokpriy honyapurvi teey farse samanya naheet. tyanche anek sambhavya fayade aahet, jase qee adhik achook mapan, qamee parikshak-prerit purvagrah aanee yadruchchik optotypes.
jarr tee vyakti, visheshtah lahan mool, dolhyanchya taktyadvare drushya tikshnatechya chachanila sahkarya karoo shakat nasel, tarr mulala changle disate qaa heey palakanna vicharoon vyavsayikanna drushya tikshnatechya sambhavya kamataratebaddal savadh kele jaau shakate. eka sanket assa aahe qee laksh kendrit karnyacha prayatna kartana mool vastoo vastoo jawal dharoo shakate. chhayachitranadware apavartak truticha andaj lavala jaau shakato, jyala photoscreening mhanatat.
tantrik tapasheel.
optotype gardi.
sanshodhananusar, ekada optotype varn 4.4 baar rundipeksha jaast antaravar aale qee, optotype 'gardi' foviatil drushya tikshnata ('vilakshan' drushya tikshnatechya viruddha) qamee karate. yala foviatil optotype aksharansathi 'critical spacing' asey mhanatat. parigh drushya tikshnatesathi, gambhir antar khoop jaast asate, jase qee 15-20 baar rundichya jawalil optotype varn durvaroon drushya tikshnatevar nakaratmak parinam karatat.

