Qalabka indhaha ee Maqaalka isha aadanaha
Qaybaha isha
Cornea-gu waa xuub hufan oo adag oo daboolaya hore ee isha. Cornea-gu wuxuu dib u celiyaa iftiinka galaya isha.
Ilkuhu waa qaybta madow ee isha. Ilkuhu waa madow, sidaas darteed waxay nuugtaa ku dhawaad dhammaan iftiinka. Ilkuhu waa god uu iftiinku ka galo isha. Inta dhexroorka ilkuhu sii weynaado, iftiinka badan ee isha soo gala iyo inta yar ee ilkuhu, iftiinka yar ee isha soo gala.
Irisku wuxuu xakameeyaa cabbirka isha. Marka deegaanka ku xeeran isha uu aad u iftiimo, irisku wuxuu yareeyaa isha. Taas bedelkeeda, marka deegaanka ku hareeraysan indhaha uu aad u iftiimo, irisku wuxuu weyneeyaa isha si cadadka iftiinka soo galaya isha uu u weynaado. Haddii aad aragtay farqiga u dhexeeya isha bisadda maalintii iyo habeenkii, markaa si fudud ayaad u fahmi kartaa shaqada irisku.
Muruqyada ciliary waxay u shaqeeyaan inay beddelaan qalooca muraayadda indhaha. Isbeddellada ku yimaada muraayadda indhaha waxay saameeyaan dhererka diiradda ee muraayadda indhaha. Haddii isha ay ku aragto walxaha meel fog, muruqyada ciliary waxay dabciyaan si gacanka qalooca muraayadda uu u kordho oo dhererka diiradda ee muraayadda uu u kordho.
Marka isha ay ku aragto walxaha meel u dhow, muruqyada ciliary-ga ayaa isku soo urura si gacanka qalooca muraayadda uu u yaraado, dhererka diiradda muraayaddana uu u yaraado. Markaa, si dadban, shaqada muruqyada ciliary-ga waa inay xakameeyaan dhererka diiradda muraayadda indhaha si isha si sax ah ugu foorarsato sawirka shayga. Isbeddelka dhererka diiradda indhaha ee isha waxaa loo yaqaan hoy u ahaanshaha indhaha.
Muraayadda indhaha waa muraayad isku dhafan ama muraayad isku dhafan ama muraayad togan. In kasta oo iftiin badan uu ka dhaco cornea-ga, muraayadda isha ayaa sidoo kale dib u celisa oo diiradda saarta iftiinka si sawirku ugu sameysmo retina-ga. Sawir waa in lagu sameeyaa retina-ga si walxaha si cad loogu arki karo. Retina-du waxay u shaqeysaa inay hirarka iftiinka u beddesho calaamado koronto, kuwaas oo markaa u gudba neerfaha indhaha una gudba maskaxda.
Hoyga isha caadiga ah
Is-waafajinta indhaha waa hagaajinta dhererka diiradda (f) ee muraayadda indhaha iyo masaafada shayga u jirta isha si sawirku diiradda ugu saaro retina. Dhererka diiradda ee muraayadda indhaha waa masaafada u dhaxaysa muraayadda indhaha iyo barta diiradda ee muraayadda (F). Marka isha la dhigo, qalooca muraayadda indhaha ayaa isbeddela, taasoo keenta in radius-ka qalooca isha uu isbeddelo sidaas darteedna dhererka diiradda ee muraayadda indhaha ayaa sidoo kale isbeddela.
Haddii isha ay ku aragto shay meel fog, muruqa ciliary wuu nastaa, taasoo keenta in muraayadda indhaha ay noqoto mid siman si ay u korodho wareegga qalooca iyo dhererka diiradda ee muraayadda. Meesha fog waa masaafada ugu fog ee isha ay diiradda saari karto, halkaas oo meesha fog ee isha caadiga ahi aanay dhammaad lahayn. Marka muruqyada ciliary ay nastaan si dhererka diiradda ee muraayadda indhaha uu u dheeraado oo uu diiradda u saaro shayga meel fog, isha waxay leedahay hoy ugu yar.
Marka isha ay aragto walxaha meel u dhow, muruqyada ciliary-ga ayaa isku soo urura, taasoo keenta in muraayadda indhaha ay noqoto mid qaloocan si ay gacanka qalooca iyo dhererka diiradda muraayadda u yaraato. Masaafada shayga ee isha ugu dhow ee wali isha ay diiradda saari karto waxaa loo yaqaan barta u dhow. Qofka caadiga ah ee aadanuhu wuxuu leeyahay meel u dhow 25 cm. Marka muruqyada ciliary-ga ay isku soo ururaan si dhererka diiradda muraayadda isha uu u gaabiyo oo uu diiradda u saaro shayga meel u dhow (25 cm), isha waxay leedahay hoy ugu badan.
Samaynta sawirka
Meesha fog
Haddii shaygu aanu dhammaad lahayn, muraayadda indhaha ayaa si siman u beddesha ilaa dhererka diiradda (f) ee muraayadda ay la mid noqoto masaafada sawirka (di). Masaafada sawirku waa masaafada u dhaxaysa muraayadda iyo meesha iftiinka iftiinka uu isgoysmo. Barta ay fallaadhaha iftiinku isgoysmo, waxay la mid tahay muraayadda indhaha. Markaa waxaa la soo gabagabeyn karaa in marka isha ay aragto shay aan dhammaad lahayn, qalooca muraayadda indhaha ayaa si siman u beddesha ilaa dhererka diiradda muraayadda (f) uu la mid noqdo masaafada u dhaxaysa muraayadda iyo muraayadda indhaha. Falaadhaha iftiinku waa inay isgoysmo gudaha muraayadda indhaha si iftiinku ugu beddelo calaamado koronto oo ku jira muraayadda indhaha.
Kuwa soo socda waa caddayn xisaabeed oo muujinaysa sababta marka shay uu ku jiro xad la'aan, dhererka diiradda muraayadda (f) uu la mid yahay masaafada sawirka (di). Xiriirka ka dhexeeya dhererka diiradda (f), masaafada shayga (do) iyo masaafada sawirka (di) waxaa lagu muujiyaa isla'egta soo socota.
1/f = 1/ samee + 1/di —- Isla'egta 1
Muraayadda indhaha waa muraayad isku soo ururaysa. Sidaa darteed, dhererka diiradda (f) waa mid togan. Masaafada shayga (do) waa mid aan dhammaad lahayn, markaa ku beddel masaafada shayga (do) ee isleegta 1 calaamad aan dhammaad lahayn.
1/f = 1/~ + 1/di
1/f = 0 + 1/di
1/f = 1/di
di = f —– Isle'egta 2
Isleegga 2aad wuxuu muujinayaa in muraayadaha isku soo ururaya haddii shaygu uu yahay mid aan dhammaad lahayn, dhererka diiradda (f) wuxuu la mid yahay masaafada sawirka (di).
Barta u dhow
Ka warran haddii shaygu u dhow yahay isha? Hore, waxaa loo sharraxay in meesha ugu dhow ee isha caadiga ah ama masaafada shayga ugu dhow ee isha caadiga ah si sax ah diiradda loo saari karo ay tahay 25 cm. Sidaa darteed, dhererka diiradda (f) ee muraayadda isha waa inuu ka yar yahay masaafada shayga (do) 25 cm. Dhererka diiradda ee muraayadda isha waa inuu ka yar yahay masaafada 25 cm si muraayadda isha ay u soo saarto sawirka dhabta ah. Muraayadda isha waa muraayad wareegsan oo samayn karta sawir dalwad ah iyo sawir dhab ah. Sawir dhab ah waxaa soo saara muraayad wareegsan marka dhererka diiradda (f) uu ka yar yahay masaafada shayga (do). Tan waxaa looga hadlay mowduuca sameynta sawirka muraayadda qulqulka.
Qiyaas dhererka diiradda (f) ee nidaamka muraayadda indhaha:
Barta u dhow isha caadiga ah waa 25 cm si masaafada shayga (yaasha) ugu dhow ay u noqoto 25 cm. Masaafada u dhaxaysa cornea iyo retina waa qiyaastii 2.5 cm. Sawirku waa cad yahay haddii iftiinka iftiinku uu ku dhaco retina si masaafada u dhaxaysa cornea iyo retina loo tixgeliyo masaafada sawirka (di). Markaa, masaafada sawirka (in) waa 2.5 cm.
1/f = 1/samayn + 1/di
1/f = 1/25 + 1/2.5 = 1/25 + 10/25 = 11/25
f = 25/11
f = 2.27 cm
Iyada oo lagu saleynayo natiijooyinka xisaabinta kor ku xusan, waxaa lagu soo gabagabeyn karaa in dhererka diiradda (f) uu ka yar yahay masaafada sawirka (di). Farqiga u dhexeeya masaafada sawirka (di) iyo dhererka diiradda (f) waa 2.5 cm – 2.27 cm = 0.23 cm. Barta diiradda ee nidaamka muraayadda indhaha ee isha cornea waa 0.23 cm dhanka bidix ee sawirka ama retina.
Nidaamka muraayadda indhaha ee cornea-indhaha waa muraayad qaloocan si sawirka loogu sameeyo retina inkastoo uu yahay mid dhab ah laakiin rogrogma. Inkasta oo sawirka retina-ku uu rogrogmayo, neerfaha maskaxdu waxay u rogaan si toosan.
