Pom yog ib qho tseem ceeb tshaj plaws ntawm tib neeg lub siab. Thaum lub teeb pom kev zoo yog ib qho nyuaj ntawm lub hlwb, cov txheej txheem yog tsav los ntawm lub teeb pom kev zoo: lub qhov muag. Nws tsim cov duab ntawm retina, qhov twg lub teeb yog absorbed los ntawm photoreceptors. Nrog lawv cov kev pab, cov teeb liab hluav taws xob raug xa mus rau qhov pom cortex rau kev ua haujlwm ntxiv.
Lub ntsiab lus tseem ceeb ntawm qhov kho qhov muag ntawm lub qhov muag: lub cornea thiab lub lens. Lawv pom lub teeb thiab ua rau nws mus rau retina. Nws yog ib qho tsim nyog sau cia tias cov cuab yeej ntawm lub qhov muag yog qhov yooj yim dua li cov koob yees duab nrog ntau lub lo ntsiab muag tsim hauv nws qhov zoo li. Txawm hais tias tsuas yog ob lub ntsiab lus ua lub luag haujlwm ntawm lo ntsiab muag hauv lub qhov muag, qhov no tsis cuam tshuam rau kev nkag siab ntawm cov ntaub ntawv.
Lub teeb
Qhov xwm txheej ntawm lub teeb kuj cuam tshuam rau qee yam ntawm lub qhov muag qhov muag. Piv txwv li, retina yog qhov rhiab tshaj plaws nyob rau hauv nruab nrab ib feem rau kev xaav ntawm qhov pom spectrum, sib xws rau cov hluav taws xob spectrum ntawm lub hnub. Lub teeb pom tau tias yog transverseelectromagnetic yoj. Pom pom wavelengths los ntawm kwv yees li xiav (400 nm) mus rau liab (700 nm) tsuas yog ib feem me me ntawm cov electromagnetic spectrum.
Nws yog qhov nthuav kom nco ntsoov tias qhov xwm txheej ntawm lub teeb (photon) tuaj yeem cuam tshuam qhov pom ntawm qee yam xwm txheej. Kev nqus ntawm photons tshwm sim hauv photoreceptors raws li cov cai ntawm cov txheej txheem random. Hauv particular, qhov kev siv ntawm lub teeb mus txog txhua tus photoreceptor txiav txim tsuas yog qhov tshwm sim ntawm absorbing ib photon. Qhov no txwv tsis pub muaj peev xwm pom ntawm qhov ci qis thiab hloov lub qhov muag mus rau qhov tsaus ntuj.
Transparency
Hauv cov tshuab kho qhov muag, cov ntaub ntawv pob tshab yog siv: iav lossis yas nrog cov khoom siv refractive. Ib yam li ntawd, tib neeg lub qhov muag yuav tsum tsim cov duab loj, kev daws teeb meem siab siv cov ntaub so ntswg nyob. Yog hais tias daim duab uas pom rau ntawm retina yog qhov muag plooj dhau, fuzzy, qhov muag pom yuav tsis ua haujlwm zoo. Yog vim li cas rau qhov no tej zaum yuav yog qhov muag thiab neuronal kab mob.
Anatomy ntawm qhov muag
Tib neeg lub qhov muag tuaj yeem piav qhia raws li cov kua dej puv quasi-spherical qauv. Optical system ntawm lub qhov muag muaj peb txheej ntawm cov ntaub so ntswg:
- external (sclera, cornea);
- internal (retina, ciliary lub cev, iris);
- intermediate (choroid).
Nyob rau hauv cov neeg laus, lub qhov muag yog kwv yees li 24 hli nyob rau hauv txoj kab uas hla thiab muaj ntau yam cellular thiab non-cellular Cheebtsam muab tau los ntawm ectodermal thiab mesodermal germlineqhov chaw.
Sab nraud ntawm lub qhov muag yog npog los ntawm cov ntaub so ntswg tiv taus thiab hloov pauv tau hu ua sclera, tshwj tsis yog rau pem hauv ntej uas lub pob tshab pob tshab tso cai rau lub teeb nkag mus rau cov menyuam kawm ntawv. Ob txheej txheej nyob rau hauv lub sclera: choroid muab cov as-ham thiab retina qhov twg lub teeb yog absorbed los ntawm photoreceptors tom qab tsim duab.
Lub qhov muag muaj zog vim yog kev ua ntawm rau lub cev nqaij daim tawv los ntes thiab luam theej duab qhov pom qhov chaw. Lub teeb nkag mus rau hauv lub qhov muag yog refracted los ntawm lub pob kws: ib txheej pob tshab uas tsis muaj cov hlab ntsha, txog 12 hli inch thiab li 0.55 hli tuab nyob rau hauv nruab nrab ib feem. Dej kua muag zaj duab xis ntawm lub pob kws lav qhov zoo tshaj plaws duab zoo.
Lub qhov muag sab hauv ntawm lub qhov muag muaj cov khoom ua kua. Lub iris, ob pawg ntawm cov leeg nrog lub hauv nruab nrab qhov uas nws qhov loj me yog nyob ntawm kev cog lus, ua zoo li lub diaphragm nrog cov yam ntxwv xim nyob ntawm tus nqi thiab kev faib cov pigments.
Tus menyuam kawm ntawv yog lub qhov nyob hauv nruab nrab ntawm iris uas tswj cov teeb pom kev nkag mus rau qhov muag. Nws qhov loj me yog li ntawm tsawg dua 2 hli hauv lub teeb ci mus rau ntau dua 8 hli hauv qhov tsaus ntuj. Tom qab cov menyuam kawm ntawv pom lub teeb, lub lens crystalline sib txuas nrog lub cornea los tsim cov duab ntawm lub retina. Lub lens crystalline tuaj yeem hloov nws cov duab. Nws yog ib puag ncig los ntawm cov tshuaj ntsiav elastic thiab txuas rau lub cev ciliary los ntawm zonules. Qhov kev txiav txim ntawm cov leeg hauv lub cev ciliary tso cai rau lub lens kom nce lossis txo nws lub zog.
Retina thiab cornea
Muaj kev nyuaj siab hauv nruab nrab hauv retina qhov twgmuaj cov receptors ntau tshaj plaws. Nws cov khoom peripheral muab kev daws teeb meem tsawg dua, tab sis tshwj xeeb hauv qhov muag txav thiab tshawb pom cov khoom. Lub ntuj pom yog loj heev piv rau cov khoom siv dag zog thiab yog 160 × 130 °. Lub macula nyob ze thiab ua haujlwm raws li lub teeb lim, supposedly tiv thaiv retina los ntawm cov kab mob degenerative los ntawm kev tshuaj xyuas cov kab xiav xiav.
Lub pob kws yog ib qho kheej kheej nrog lub voj voog sab nrauv ntawm 7.8 hli, lub voj voog tom qab curvature ntawm 6.5 hli thiab ib qho inhomogeneous refractive index ntawm 1.37 vim cov txheej txheem txheej.
qhov muag loj thiab tsom
Qhov nruab nrab qhov muag zoo li qub muaj tag nrho axial ntev ntawm 24.2 hli thiab cov khoom nyob deb tau tsom raws nraim ntawm qhov nruab nrab ntawm retina. Tab sis kev sib txawv ntawm qhov loj ntawm lub qhov muag tuaj yeem hloov qhov xwm txheej:
- myopia, thaum cov duab tsom mus rau pem hauv ntej ntawm retina,
- farsightedness thaum nws tshwm sim tom qab nws.
Lub luag haujlwm ntawm lub qhov muag qhov muag kuj raug ua txhaum thaum astigmatism - qhov curvature ntawm lub lens tsis raug.
duab zoo ntawm lub retina
Txawm tias thaum lub qhov muag pom qhov muag pom tau zoo, nws tsis tsim cov duab zoo meej. Ntau yam cuam tshuam qhov no:
- diffraction ntawm lub teeb nyob rau hauv cov tub kawm ntawv (blur);
- optical aberrations (qhov loj dua cov menyuam kawm ntawv, qhov pom kev tsis zoo);
- muag hauv qhov muag.
Cov duab tshwj xeeb ntawm lub qhov muag, qhov ntsuas qhov ntsuas qhov sib txawv, thiab cov duab geometry yog qhov tsis txaus ntawm lub qhov muag qhov muag.piv rau cov khoom siv dag zog. Lub qhov muag ib txwm muaj tsawg kawg yog rau lub sij hawm qis dua thiab txhua tus tsim ib qho bitmap qub nyob ntawm qhov aberrations tam sim no. Yog li, piv txwv li, cov duab pom ntawm cov hnub qub yuav txawv ntawm ib tus neeg mus rau lwm tus.
Kev pom tsis pom kev
Lub hauv nruab nrab ntawm lub retina muab qhov kev daws teeb meem loj tshaj plaws, tab sis qhov tsis tshua muaj kev ceev faj ntawm sab hauv kuj tseem ceeb. Ua tsaug rau peripheral tsis pom kev, tus neeg tuaj yeem taug kev hauv qhov tsaus ntuj, paub qhov txawv ntawm qhov kev txav mus los, thiab tsis yog qhov khoom txav nws tus kheej thiab nws cov duab, thiab taug kev hauv qhov chaw. Peripheral vision yog feem ntau nyob rau hauv cov tsiaj thiab noog. Ntxiv mus, ib txhia ntawm lawv muaj lub kaum sab xis saib ntawm tag nrho 360 ° kom muaj kev muaj sia nyob ntau dua. Kev pom kev tsis pom kev yog xam los ntawm cov yam ntxwv ntawm lub zeem muag peripheral.
Result
Qhov kev kho qhov muag ntawm tib neeg lub qhov muag yog qhov yooj yim thiab txhim khu kev qha thiab ua tau zoo rau kev nkag siab ntawm lub ntiaj teb ib puag ncig. Txawm hais tias qhov zoo ntawm qhov pom yog qis dua hauv cov txheej txheem kev tshaj lij, nws ua tau raws li qhov xav tau ntawm lub cev. Lub qhov muag muaj ntau yam kev them nyiaj rov qab uas tso qee qhov kev txwv qhov muag tsis pom zoo. Piv txwv li, qhov cuam tshuam loj ntawm chromatic defocusing yog tshem tawm los ntawm cov xim lim dej uas tsim nyog thiab bandpass spectral rhiab heev.
Nyob rau hauv lub xyoo caum kawg, muaj peev xwm kho qhov muag aberrations siv adaptiveoptics. Qhov no yog tam sim no technically ua tau nyob rau hauv lub chav kuaj nrog kho cov cuab yeej xws li intraocular lo ntsiab muag. Kev kho tuaj yeem rov qab muaj peev xwm pom, tab sis muaj qhov nuance - kev xaiv ntawm photoreceptors. Txawm hais tias cov duab ntse tau npaj rau ntawm retina, tsab ntawv me tshaj plaws kom pom tau yuav xav tau ntau lub photoreceptors los txhais kom raug. Cov duab ntawm cov tsiaj ntawv me dua qhov pom kev sib raug zoo yuav tsis raug qhov txawv.
Txawm li cas los xij, qhov pom kev tsis pom kev tseem ceeb yog qhov tsis muaj zog aberrations: defocusing thiab astigmatism. Cov teeb meem no tau raug kho tau yooj yim los ntawm ntau yam kev tsim kho tshuab txij li xyoo pua kaum peb, thaum lub cylindrical lo ntsiab muag tau tsim. Cov txheej txheem niaj hnub no koom nrog kev siv cov kev sib cuag thiab cov lo ntsiab muag intraocular lossis laser refractive phais cov txheej txheem los hloov kho cov qauv ntawm tus neeg mob qhov kho qhov muag.
Lub neej yav tom ntej ntawm ophthalmology zoo li cog lus. Photonics thiab teeb pom kev zoo tshuab yuav ua lub luag haujlwm tseem ceeb hauv nws. Kev siv cov optoelectronics siab heev yuav tso cai rau cov prostheses tshiab los kho qhov muag pom deb yam tsis tau tshem tawm cov ntaub so ntswg, zoo li tam sim no. Tshiab optical coherence tomography yuav muab tag nrho-scale real-time 3D visualization ntawm lub qhov muag. Kev tshawb fawb tsis nyob twj ywm kom lub qhov muag kho qhov muag tso cai rau peb txhua tus pom lub ntiaj teb nyob rau hauv tag nrho nws lub yeeb koob.
