Iris na cikin tsarin gani na ido, yana daidaita yawan hasken da ke wucewa ta cikin almajiri. Bangaren ido ne mai launi.

Iris wani sinadari ne na kwan fitilar ido, yana cikin rigarsa na jijiyoyin jini (tsakiyar Layer). Yana samuwa a gaban ido, tsakanin cornea da ruwan tabarau, a cikin ci gaba da choroid. Almajiri ne ya huda shi a tsakiyarsa wanda ke ba da damar haske ya shiga cikin ido. Yana aiki akan diamita na ɗalibin ta hanyar aikin tsoka mai santsi na madauwari ( tsokar sphincter) da haskoki ( tsokar dilator).

Ikon ɗalibi

Iris yana bambanta buɗewar almajiri ta hanyar yin kwangila ko fadada tsokoki na sphincter da dilator. Kamar diaphragm a cikin kyamara, don haka yana sarrafa adadin hasken da ke shiga ido. Lokacin da ido ya lura da wani abu na kusa ko haske yana haskakawa, tsokar sphincter yana yin kwangila: almajiri yana ƙarfafawa. Akasin haka, lokacin da ido ya kalli wani abu mai nisa ko kuma lokacin da hasken ya yi rauni, tsokar dilator tana yin kwangila: almajiri yana faɗaɗa, diamita yana ƙaruwa kuma yana barin ƙarin haske ya wuce.

Launukan ido

Launi na iris ya dogara ne akan maida hankali na melanin, launin ruwan kasa mai launin ruwan kasa, wanda kuma ake samu a cikin fata ko gashi. Mafi girma da maida hankali, da duhu idanu. Idanun shuɗi, kore ko hazel suna da matsakaicin yawa.

Aniridie : sakamakon rashin iris. Yana da lahani na kwayoyin halitta wanda ke bayyana a lokacin haihuwa ko lokacin yaro. Rare Pathology, yana shafar 1/40 haihuwa a kowace shekara. Adadin hasken da ke shiga ido ba a sarrafa shi: da yawa, zai iya lalata sauran tsarin ido. Aniridia na iya zama mai rikitarwa ta cataracts ko glaucoma, alal misali.

Ocular albinism : cutar cututtukan da ke nuna rashi ko raguwar melanin a cikin iris da retina. A wannan yanayin, iris yana bayyana shuɗi ko launin toka tare da almajiri ja mai haske saboda jijiyoyin jini da ake iya gani a bayyane. Wannan depigmentation shi ne saboda rashi ko rashi na tyrosinase, wani enzyme da ke cikin samar da melanin pigments. Alamomin da aka gani gabaɗaya sune:

• nystagmus: motsin idanu
• photophobia: rashin haƙuri na idanu zuwa haske wanda zai iya haifar da ciwon ido
• raguwar hangen nesa: myopia, hyperopia ko astigmatism na iya shafar mutanen da ke da zabiya.

Wannan depigmentation kuma na iya shafar fata da gashi, muna magana akan albinism na oculocutaneous. Wannan cuta tana haifar da fata mai kyan gani da fari fari ko gashi mai gashi.

Ciwon ciki : wanda aka fi sani da "idon bango", ba cuta ba ne amma yanayin jiki ne kawai wanda ke haifar da wani bangare ko duka bambancin launi na iris. Yana iya shafar irises na idanu biyu kuma yana bayyana a lokacin haihuwa ko kuma zai iya haifar da cututtuka irin su cataracts ko glaucoma.

Heterochromia na iya shafar karnuka da kuliyoyi. Daga cikin mashahuran mutane, David Bowie an kwatanta shi a matsayin mai duhu idanu. Amma launin ruwan kasa a idonsa na hagu ya kasance saboda mydriasis na dindindin, sakamakon bugun da ya samu a shekarun samartaka. Mydriasis shine haɓakar dabi'a na ɗalibi a cikin duhu domin ya kawo haske gwargwadon iyawa cikin ido. Ga Bowie, tsokar da ke cikin iris ɗinsa ya lalace sakamakon bugun da ya sa ɗalibin nasa ya faɗi har abada tare da canza launin idonsa.

Babu maganin wadannan cututtuka. Fitar da rana ga mutanen da ke da zabiya na iya haifar da lalacewar fata kuma haɗarin su na cutar kansar fata yana da yawa. Don haka Hukumar Lafiya ta Duniya (WHO) (6) ta ba da shawarar cewa kada ka taba kai wa ga hasken rana kai tsaye, tun daga karama. Ana ba da shawarar sanya hula da tabarau tunda iris ɗin da ba ya da launi ya daina yin rawarsa a matsayin shinge ga hasken ultraviolet na rana.

Iridologie : a zahiri "nazarin iris". Wannan al'ada ta ƙunshi karantawa da fassara iris don ganin yanayin jikinmu da yin gwajin lafiya. Wannan dabarar da aka yi hamayya ba ta taɓa samun ingantacciyar hanyar kimiyya ta hanyar bincike ba.

Biometrics da iris ganewa

Kowane iris yana da tsari na musamman. Yiwuwar gano irises iri ɗaya guda biyu shine 1/1072, a wasu kalmomi ba zai yiwu ba. Hatta tagwaye iri ɗaya suna da irises daban-daban. Kamfanonin halittu suna yin amfani da wannan halayyar da ke haɓaka dabarun gano mutane ta hanyar gane irises. Yanzu haka hukumomin kwastam na amfani da wannan hanyar a duk duniya, a bankuna ko a gidajen yari (8).

Me yasa jarirai ke da idanu shudi?

A lokacin haihuwa, ana binne pigments na melanin a cikin iris (9). Zurfinsa, mai launin shuɗi- launin toka, ana iya gani a bayyane.

Wannan shine dalilin da ya sa wasu jarirai suna da idanu masu launin shuɗi. A cikin makonni, melanin zai iya tashi zuwa saman iris kuma ya canza launin idanu. Ajiye a saman melanin zai haifar da idanu masu launin ruwan kasa yayin da idan bai tashi ba, idanun za su kasance shuɗi. Amma lamarin bai shafi dukkan jarirai ba: yawancin jariran Afirka da Asiya sun riga sun sami duhun idanu lokacin da aka haife su.

Blue idanu, juyin halitta

Asali, duk maza suna da idanu masu launin ruwan kasa. Wani maye gurbi na kwatsam ya shafi aƙalla babban nau'in launi na ido guda ɗaya, kuma idanun shuɗi sun bayyana. Bisa ga binciken 10 (2008), wannan maye gurbi ya bayyana 6000 zuwa 10 shekaru da suka wuce kuma ya samo asali daga kakanni guda. Wannan maye gurbin zai iya yaduwa zuwa ga dukkan jama'a.

Wasu bayanai kuma suna yiwuwa, duk da haka: wannan maye gurbi zai iya faruwa sau da yawa a kansa, ba tare da asali ɗaya ba, ko wasu maye gurbi na iya haifar da idanu shuɗi.