Muaj ntau yam kev ntsuam xyuas kom pom qhov muag tsis pom xim, qhov pom kev tsis pom kev cuam tshuam rau qhov sib txawv ntawm cov xim, thiab cuam tshuam rau 8% ntawm cov txiv neej cov pej xeem tawm tsam tsuas yog 0,45% ntawm cov poj niam. Qhov zoo tshaj plaws paub ntawm cov kev xeem no yog ntawm Ishihara.

Kev dig muag xim (npe tom qab xyoo pua 18th English physicist John Dalton) yog qhov tsis pom kev cuam tshuam rau kev nkag siab ntawm xim. Nws yog kab mob caj ces: nws yog vim muaj qhov tsis zoo (tsis muaj lossis hloov pauv) nyob rau hauv cov noob encoding xim liab thiab ntsuab, ob qho tib si nyob rau ntawm X chromosome, los yog ntawm cov noob encoding xiav, ntawm chromosome 7 Xim qhov muag tsis pom kev yog vim li no, vim hais tias ib tug los yog ob leeg niam txiv tuaj yeem dhau ntawm qhov kev hloov caj ces no. Nws muaj ntau dua rau cov txiv neej vim lawv nqa ob X chromosomes. Tsis tshua muaj, qhov muag tsis pom xim tuaj yeem ua rau mob qhov muag lossis mob dav dav (mob ntshav qab zib).

Nyob ntawm seb qhov txawv txav ntawm caj ces, muaj ntau hom xim dig muag:

Monochromatism (los yog achromatism): tus neeg tsis paub qhov txawv ntawm cov xim thiab yog li pom tsuas yog dub, dawb thiab ntxoov grey. Qhov no anomaly yog tsawg heev.

Lub dichromie : ib qho ntawm cov noob, thiab yog li ntawd ib qho ntawm cov pigments, tsis tuaj.

• Yog hais tias nws yog cov noob encoding liab, tus neeg yog protanopic: nws perceives xiav thiab ntsuab;
• Yog hais tias nws yog cov noob encoding ntsuab, tus neeg yog deuteranopic: nws perceives xiav thiab ntsuab;
• Yog hais tias nws yog cov noob coding rau xiav, tus neeg yog tritanopic: nws perceives liab thiab ntsuab.

Qhov txawv txav trichomatie : ib tug ntawm cov noob yog mutated, kev xaav ntawm cov xim yog li hloov.

• Yog hais tias nws yog cov noob encoding liab, tus neeg yog protanormal: lawv muaj teeb meem perceiving liab;
• Yog hais tias nws yog cov noob coding rau ntsuab, tus neeg yog deuteranormal: lawv muaj teeb meem perceiving ntsuab;
• Yog hais tias nws yog cov noob coding rau xiav, tus neeg yog tritanormal: lawv muaj teeb meem perceiving xiav.

Txhawm rau txheeb xyuas cov kev tsis zoo no, muaj ntau yam kev ntsuam xyuas. Nov yog cov tseem ceeb:

• le sim Ishihara, muaj npe tom qab nws tus tsim Japanese Shinobu Ishihara (1879-1963), yog qhov nquag siv. Nws tso cai rau kev txheeb xyuas qhov pom ntawm liab thiab ntsuab tsis txaus (protanopia, protanomaly, deuteranopia, deuteranomaly). Nws los nyob rau hauv daim ntawv ntawm 38 thiaj li hu ua pseudo-isochromatic daim hlau: nyob rau hauv ib lub voj voog muaj cov dots ntawm ntau thiab tsawg thiab xim, los ntawm uas sawv tawm, rau cov neeg uas perceives ib txwm (trichomate), ib tug xov tooj. Cov phiaj xwm no tau nthuav tawm hauv kev txiav txim meej rau tus neeg mob, leej twg yuav tsum hais tus lej nws txawv lossis tsis.
• le test "xim pom tau yooj yim" yog cov menyuam yaus version ntawm pseudo-isochromatic xeem. Hloov ntawm cov duab, cov no yog cov duab uas tuaj yeem paub qhov txawv ntawm cov laug cam.
• les xeem Vaj Huam Sib Luag D15 thiab Farnsworth-Munsell 100-hue, tsim los ntawm Dean Farnsworth xyoo 1943, tuaj hauv daim ntawv ntawm cov xim me me kom muab tso rau hauv qhov kev txiav txim kom raug.
• Le test d'Holmgren siv cov xim skeins ntawm wool. Peb ntawm lawv ua haujlwm raws li kev siv: skein A rau ntsuab, B rau ntshav thiab C rau liab. Tus neeg mob yuav tsum xaiv ntawm 40 lwm skeins 10 uas ze tshaj rau xim A, 5 mus rau xim B thiab tom qab ntawd 5 mus rau C. Nws yuav tsum tau muab faib ua xim xim. Qhov kev sim no tsuas yog siv los kuaj xyuas qhov muag tsis pom xim hauv cov neeg tsav nkoj, cov neeg ua haujlwm hauv tsheb ciav hlau thiab cov neeg caij tsheb, cov haujlwm txwv tsis pub rau cov neeg dig muag xim vim yog siv cov cim liab thiab ntsuab.
• xeem Verriest, tsim nyob rau hauv 1981, yog npaj rau cov me nyuam. nws tuaj nyob rau hauv daim ntawv ntawm cov xim tokens los sib sau ua ke, zoo li domino.
• le sim Pease and Allen (1988) kuj yog npaj rau menyuam yaus. Nws tuaj nyob rau hauv daim ntawv ntawm 4 xim duab plaub (dawb, liab, ntsuab thiab xiav) nrog ib tug me me square ntawm ib tug txawv xim nyob rau hauv ib lub ces kaum, nyob rau sab saum toj ntawm lub duab plaub. Tus menyuam yuav tsum paub cov xim.

Cov kev ntsuam xyuas no tau ua nyob rau hauv qhov xwm txheej ntawm qhov tsis txaus ntseeg ntawm qhov muag tsis pom xim, hauv "tsev neeg" ntawm cov neeg dig muag xim lossis thaum nrhiav haujlwm rau qee yam haujlwm (cov haujlwm thauj pej xeem tshwj xeeb).

Tsis muaj kev kho rau qhov muag tsis pom xim, uas tsis zoo zuj zus lossis txhim kho ntau xyoo. Thiab cov neeg uas muaj qhov muag tsis pom xim feem ntau ua tau zoo heev nrog qhov tshwj xeeb me me no.

Muaj, tau kawg, tsom iav, thiab txawm tias lo ntsiab muag tshwj xeeb, uas muaj cov xim lim los hloov cov xim spectrum, tab sis lawv feem ntau siv me ntsis.