I-Astigmatism ingenye yezifo eziyinkimbinkimbi kakhulu ekulungiseni ukukhubazeka kombono, futhi ngesikhathi esifanayo yiyona evame kakhulu phakathi kwamaqembu ahlukene abantu.
I-Astigmatism ingahlanganiswa ne-myopia ne-hyperopia, futhi eyamukelekayo kakhulu ezimweni eziningi iyalungiswa ngosizo lwezibuko ezikhethekile, ama-lens azokhokha izidakamizwa ezibukwayo.
Uma uhumusha incazelo yegama elithi "astigmatism" elisuka kwisiLatini, akulula ukuqonda ukuthi kusho ukuthini ukungabi khona kwephuzu elibalulekile. Ngenxa yesakhiwo esingalungile se-cornea noma i-lens, ukuphazamiseka kwabo kuphazanyiswa, futhi isithombe esibonakalayo sibonakala siphutha.
Amaphuzu we-astigmatism akulula ukuwuthatha, ngoba umuntu akakwazi ukubona kokubili izinto ezikude futhi ezikude, futhi kuvela ukuthi kulezi zimo ezimbili ziyadingeka.
Ngoba namuhla kunezinto ezibizwa ngokuthi i-progressive-bifocals lenses zezibuko, ezihlanganisa imisebenzi emibili - ukulungiswa kombukiso we-myopia nokubukeka phambili.
Indlela yokukhetha izibuko nge-astigmatism?
Ngokokuqala ngqa umqondo wokuhlanganisa izinhlobo ezimbili zama-lens wafika kuBenjamin Franklin, owayekhathele ukushintsha ama-pair of glasses. Ngomnyaka we-1780 wathatha ama-lensi amabili ahlukeneko ebangeni begodu eduze, wawasika begodu wawafaka ehlathini. Indawo ephezulu yayigcwele i-lens yokubona ubude, futhi isuka ngaphansi kwe- myopia . Lesi yisinyathelo esisha ku-ophthalmology - manje abantu banethuba lokusebenzisa izibuko ezilodwa ukuxazulula izinkinga ezimbili ngesikhathi esisodwa. Yiqiniso, kusukela ngo-1780 isimo sesishintshile kancane, kanti izibuko zithuthukisiwe, kodwa umqondo kaBenjamin usuhlale uhlala endaweni ehamba phambili ekudaleni ama-bifocals.
Ukukhethwa kwezibuko nge-astigmatism akuyona into elula, ukuqaliswa okuphumelelayo yiziphi izici eziningana okufanele zicatshangelwe:
- iminyaka yesiguli;
- i-astigmatism;
- Ukubona komuntu ngamunye ngamalensi ngokulungiswa kwamazinga ahlukahlukene.
Phakathi nomkhuba, odokotela bathola ukuthi iziguli ezine-astigmatism zinzima kanzima ukugqoka izilensi zokulungisa - zinesifo esibuhlungu, isizungu, nobuhlungu emehlweni. Okhulile isiguli, kungenzeka ukuthi izibuko ezithinta izidakamizwa zizoletha ukungalungi.
Ngakho-ke, ngokuqala isiguli sinikezwa ukugqoka izibuko ezingagcini ngokuphelele umbono, futhi emva kwezinyanga ezimbalwa zincoma ukuthi zibeke "amalensi aqinile" ahlawulisa ukukhubazeka okubukwayo 100%.
Ngama-glasses ayingqayizivele nge-astigmatism, odokotela baqonda ama-lense ngendawo engavamile engavamile. Njengoba i-cornea ne-lens ingavamile kule sifo, ukuze kulungiswe umbono wezithombe, kuzomele wenze ilensi ekhethekile ezobuyisela isimo esingenakukhubazeka. Njengoba i-astigmatism elula, i-lens ifana ne-oval, hhayi i-sphere -
Ukulungiswa kwe-astigmatism elula
I-lens cylindrical isetshenziselwa ukulungisa i-astigmatism elula, lapho ukuphazamiseka kuphazamiseka kuphela ku-meridian eyodwa, futhi kuye ngokuthi lokhu, kungase kuqoqwe noma kuhlakazeke. I-lens ye-cylindrical ayifani nomphumela wayo ku-lens evamile ye-spherical lens, ngoba ayiphikisi imigwaqo ekhanyayo ewela ngokuhambisana ne-axis yayo. Ngalo, imisebe kuphela ewela ngokuqondile engxenyeni ye-axis iyaphikiswa.
Ukulungiswa kwe-astigmatism eyinkimbinkimbi
Nge-astigmatism ehlanganisiwe noma eyinkimbinkimbi, kusetshenziswe i-lens toric, lapho kuhlanganiswa khona amalensi e-cylindrical and spherical. Kulesi simo, ngayinye yezikhombisi zokuqeda (zihlukile) zinemvume yayo.