少年學生如果不注意保護視力，容易造成近視。這(zhe)是因為眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)睛(jing)(jing)在(zai)(zai)看(kan)5米以(yi)(yi)外的(de)(de)(de)(de)目標(biao)時(shi)，平(ping)行光(guang)線恰(qia)好在(zai)(zai)視(shi)(shi)(shi)(shi)(shi)(shi)網(wang)(wang)膜(mo)上(shang)成像(xiang)(xiang)，而(er)能(neng)(neng)(neng)清晰地辨認遠(yuan)處(chu)目標(biao)。若(ruo)看(kan)5米以(yi)(yi)內(nei)的(de)(de)(de)(de)物(wu)(wu)體(ti)(ti)時(shi)，眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)睛(jing)(jing)就必須增(zeng)(zeng)強(qiang)屈光(guang)力(li)(li)(li)，這(zhe)時(shi)眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)內(nei)的(de)(de)(de)(de)睫狀肌收縮，晶(jing)狀體(ti)(ti)變(bian)(bian)凸(tu)，使(shi)物(wu)(wu)像(xiang)(xiang)仍能(neng)(neng)(neng)成像(xiang)(xiang)在(zai)(zai)視(shi)(shi)(shi)(shi)(shi)(shi)網(wang)(wang)膜(mo)上(shang)，眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)睛(jing)(jing)的(de)(de)(de)(de)這(zhe)種自動調節由遠(yuan)看(kan)近(jin)(jin)(jin)(jin)(jin)(jin)的(de)(de)(de)(de)能(neng)(neng)(neng)力(li)(li)(li)叫(jiao)調能(neng)(neng)(neng)作(zuo)(zuo)用(yong)(yong)。目標(biao)愈近(jin)(jin)(jin)(jin)(jin)(jin)，使(shi)用(yong)(yong)的(de)(de)(de)(de)調節力(li)(li)(li)愈大。如(ru)果(guo)青少年長(chang)(chang)期不(bu)(bu)(bu)適(shi)當讀書、寫字或照(zhao)明不(bu)(bu)(bu)足等因素(su)，使(shi)睫狀肌經常處(chu)于收縮狀態，變(bian)(bian)凸(tu)的(de)(de)(de)(de)晶(jing)狀體(ti)(ti)不(bu)(bu)(bu)易松弛，這(zhe)時(shi)，遠(yuan)處(chu)平(ping)行光(guang)線進入眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)內(nei)，經過(guo)變(bian)(bian)凸(tu)的(de)(de)(de)(de)晶(jing)狀體(ti)(ti)較(jiao)強(qiang)的(de)(de)(de)(de)屈折后，其焦點就不(bu)(bu)(bu)再落在(zai)(zai)視(shi)(shi)(shi)(shi)(shi)(shi)網(wang)(wang)膜(mo)上(shang)，而(er)落在(zai)(zai)視(shi)(shi)(shi)(shi)(shi)(shi)網(wang)(wang)膜(mo)前面，看(kan)東西模糊(hu)不(bu)(bu)(bu)清，醫(yi)學上(shang)叫(jiao)假性(xing)近(jin)(jin)(jin)(jin)(jin)(jin)視(shi)(shi)(shi)(shi)(shi)(shi)。因為眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)球(qiu)(qiu)前后徑并(bing)沒有(you)(you)加(jia)長(chang)(chang)，眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)球(qiu)(qiu)結(jie)構(gou)并(bing)未發生變(bian)(bian)化(hua)，僅僅是生理機能(neng)(neng)(neng)的(de)(de)(de)(de)改(gai)(gai)變(bian)(bian)，所以(yi)(yi)，一般不(bu)(bu)(bu)要(yao)配(pei)(pei)戴(dai)。經過(guo)及時(shi)治(zhi)療(liao)和注意保護，使(shi)睫狀肌放松，視(shi)(shi)(shi)(shi)(shi)(shi)力(li)(li)(li)可(ke)(ke)以(yi)(yi)恢復(fu)正常。如(ru)在(zai)(zai)假性(xing)近(jin)(jin)(jin)(jin)(jin)(jin)視(shi)(shi)(shi)(shi)(shi)(shi)階(jie)(jie)段不(bu)(bu)(bu)引起(qi)重視(shi)(shi)(shi)(shi)(shi)(shi)，繼續(xu)發展(zhan)下去，眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)球(qiu)(qiu)的(de)(de)(de)(de)前后軸變(bian)(bian)長(chang)(chang)，這(zhe)時(shi)眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)球(qiu)(qiu)的(de)(de)(de)(de)結(jie)構(gou)發生改(gai)(gai)變(bian)(bian)，即成為真(zhen)性(xing)近(jin)(jin)(jin)(jin)(jin)(jin)視(shi)(shi)(shi)(shi)(shi)(shi)，就必須用(yong)(yong)配(pei)(pei)戴(dai)眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)鏡來矯(jiao)治(zhi)。孩子得(de)(de)了近(jin)(jin)(jin)(jin)(jin)(jin)視(shi)(shi)(shi)(shi)(shi)(shi)眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)，應(ying)到(dao)(dao)醫(yi)院檢(jian)查，一旦診斷為假性(xing)近(jin)(jin)(jin)(jin)(jin)(jin)視(shi)(shi)(shi)(shi)(shi)(shi)，不(bu)(bu)(bu)要(yao)配(pei)(pei)戴(dai)眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)鏡，因為還是功(gong)能(neng)(neng)(neng)階(jie)(jie)段，經過(guo)適(shi)當治(zhi)療(liao)，視(shi)(shi)(shi)(shi)(shi)(shi)力(li)(li)(li)有(you)(you)恢復(fu)的(de)(de)(de)(de)可(ke)(ke)能(neng)(neng)(neng)。如(ru)果(guo)過(guo)早地戴(dai)上(shang)眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)鏡，可(ke)(ke)能(neng)(neng)(neng)把所配(pei)(pei)近(jin)(jin)(jin)(jin)(jin)(jin)視(shi)(shi)(shi)(shi)(shi)(shi)的(de)(de)(de)(de)度數固定下來，變(bian)(bian)成真(zhen)性(xing)近(jin)(jin)(jin)(jin)(jin)(jin)視(shi)(shi)(shi)(shi)(shi)(shi)或造工(gong)，增(zeng)(zeng)加(jia)眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)睛(jing)(jing)的(de)(de)(de)(de)疲勞(lao)感覺。一般新得(de)(de)的(de)(de)(de)(de)近(jin)(jin)(jin)(jin)(jin)(jin)視(shi)(shi)(shi)(shi)(shi)(shi)，或視(shi)(shi)(shi)(shi)(shi)(shi)力(li)(li)(li)在(zai)(zai)0.7以(yi)(yi)上(shang)，經醫(yi)生檢(jian)查證(zheng)實為近(jin)(jin)(jin)(jin)(jin)(jin)視(shi)(shi)(shi)(shi)(shi)(shi)一百度以(yi)(yi)內(nei)者，可(ke)(ke)暫時(shi)不(bu)(bu)(bu)配(pei)(pei)戴(dai)眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)鏡。因為：這(zhe)樣的(de)(de)(de)(de)視(shi)(shi)(shi)(shi)(shi)(shi)力(li)(li)(li)并(bing)不(bu)(bu)(bu)影(ying)響(xiang)孩子的(de)(de)(de)(de)學習(xi)(xi)；可(ke)(ke)以(yi)(yi)避(bi)(bi)免(mian)假性(xing)近(jin)(jin)(jin)(jin)(jin)(jin)視(shi)(shi)(shi)(shi)(shi)(shi)誤(wu)為真(zhen)性(xing)近(jin)(jin)(jin)(jin)(jin)(jin)視(shi)(shi)(shi)(shi)(shi)(shi)；可(ke)(ke)以(yi)(yi)減(jian)輕(qing)調節功(gong)能(neng)(neng)(neng)的(de)(de)(de)(de)負擔。假性(xing)近(jin)(jin)(jin)(jin)(jin)(jin)視(shi)(shi)(shi)(shi)(shi)(shi)如(ru)果(guo)通(tong)過(guo)矯(jiao)治(zhi)，視(shi)(shi)(shi)(shi)(shi)(shi)力(li)(li)(li)增(zeng)(zeng)進不(bu)(bu)(bu)明顯，同(tong)時(shi)對(dui)(dui)學習(xi)(xi)有(you)(you)影(ying)響(xiang)，應(ying)配(pei)(pei)戴(dai)近(jin)(jin)(jin)(jin)(jin)(jin)視(shi)(shi)(shi)(shi)(shi)(shi)眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)鏡。配(pei)(pei)鏡時(shi)，一定要(yao)經眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)科(ke)醫(yi)生和驗(yan)光(guang)師做散瞳(tong)驗(yan)光(guang)。不(bu)(bu)(bu)要(yao)借用(yong)(yong)他人的(de)(de)(de)(de)眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)鏡戴(dai)用(yong)(yong)或隨便買一副現成眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)鏡戴(dai)上(shang)，因為度數不(bu)(bu)(bu)對(dui)(dui)會增(zeng)(zeng)加(jia)調節負擔。輕(qing)度近(jin)(jin)(jin)(jin)(jin)(jin)視(shi)(shi)(shi)(shi)(shi)(shi)(300度以(yi)(yi)內(nei))可(ke)(ke)以(yi)(yi)在(zai)(zai)上(shang)課或看(kan)遠(yuan)時(shi)戴(dai)用(yong)(yong)眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)鏡，度數較(jiao)深的(de)(de)(de)(de)近(jin)(jin)(jin)(jin)(jin)(jin)視(shi)(shi)(shi)(shi)(shi)(shi)，則應(ying)長(chang)(chang)期戴(dai)用(yong)(yong)，以(yi)(yi)免(mian)度數加(jia)深。在(zai)(zai)戴(dai)鏡的(de)(de)(de)(de)同(tong)時(shi)還應(ying)認真(zhen)注意用(yong)(yong)眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)衛生，特別要(yao)做到(dao)(dao)避(bi)(bi)免(mian)“兩長(chang)(chang)一短”和“兩多(duo)(duo)一少”(即每天學習(xi)(xi)時(shi)間長(chang)(chang)，持續(xu)用(yong)(yong)眼(yan)(yan)(yan)(yan)(yan)(yan)(yan)(yan)時(shi)間長(chang)(chang)，時(shi)間短；作(zuo)(zuo)業多(duo)(duo)，考試(shi)多(duo)(duo)，課外活動少)。晚(wan)上(shang)在(zai)(zai)家里做作(zuo)(zuo)業時(shi)還應(ying)有(you)(you)良(liang)好的(de)(de)(de)(de)照(zhao)明和合適(shi)的(de)(de)(de)(de)桌椅。平(ping)時(shi)要(yao)多(duo)(duo)吃蔬菜(cai)和水果(guo)，也(ye)不(bu)(bu)(bu)要(yao)在(zai)(zai)運(yun)行的(de)(de)(de)(de)車輛上(shang)閱讀書籍(ji)，并(bing)定期檢(jian)查視(shi)(shi)(shi)(shi)(shi)(shi)力(li)(li)(li)。如(ru)果(guo)發現視(shi)(shi)(shi)(shi)(shi)(shi)力(li)(li)(li)減(jian)退或不(bu)(bu)(bu)足1.0，應(ying)查明原因及時(shi)給予矯(jiao)治(zhi)。

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