{"id":3851,"date":"2020-03-17T17:39:01","date_gmt":"2020-03-17T10:39:01","guid":{"rendered":"http:\/\/matquocte.vn\/?p=3851"},"modified":"2023-12-20T08:39:28","modified_gmt":"2023-12-20T01:39:28","slug":"phan-loai-can-thi-va-nhung-nguyen-nhan-dan-den-can-thi","status":"publish","type":"post","link":"https:\/\/matquocte.vn\/en\/tieng-viet-phan-loai-can-thi-va-nhung-nguyen-nhan-dan-den-can-thi\/","title":{"rendered":"(Ti\u1ebfng Vi\u1ec7t) Ph\u00e2n lo\u1ea1i c\u1eadn th\u1ecb v\u00e0 nh\u1eefng nguy\u00ean nh\u00e2n d\u1eabn \u0111\u1ebfn c\u1eadn th\u1ecb"},"content":{"rendered":"

Sorry, this entry is only available in Ti\u1ebfng Vi\u1ec7t<\/a>. For the sake of viewer convenience, the content is shown below in the alternative language. You may click the link to switch the active language.<\/p>

<\/p>\n

C\u1eadn th\u1ecb l\u00e0 m\u1ed9t t\u1eadt kh\u00fac x\u1ea1 ph\u1ed5 bi\u1ebfn, b\u1ec7nh nh\u00e2n b\u1ecb gi\u1ea3m t\u1ea7m nh\u00ecn khi nh\u00ecn xa.\u00a0 Ng\u01b0\u1eddi b\u1ecb c\u1eadn n\u00ean bi\u1ebft c\u00e1ch ph\u00e2n bi\u1ec7t c\u00e1c d\u1ea1ng b\u1ec7nh kh\u00e1c nhau \u0111\u1ec3 c\u00f3 ph\u01b0\u01a1ng ph\u00e1p \u0111i\u1ec1u tr\u1ecb c\u1eadn th\u1ecb ph\u00f9 h\u1ee3p.<\/p>\n

A. Ph\u00e2n lo\u1ea1i c\u1eadn th\u1ecb<\/h4>\n
    \n
  1. Ph\u00e2n lo\u1ea1i theo th\u1ec3 l\u00e2m s\u00e0ng:<\/li>\n<\/ol>\n
      \n
    • C\u1eadn th\u1ecb \u0111\u01a1n thu\u1ea7n: c\u00f3 th\u1ec3 xu\u1ea5t hi\u1ec7n do s\u1ef1 b\u1ea5t c\u00e2n x\u1ee9ng gi\u1eefa c\u00f4ng su\u1ea5t quang h\u1ec7 ( gi\u00e1c m\u1ea1c v\u00e0 th\u1ec3 th\u1ee7y tinh ) v\u00e0 chi\u1ec1u d\u00e0i tr\u1ee5c tr\u01b0\u1edbc sau c\u1ee7a nh\u00e3n c\u1ea7u, th\u01b0\u1eddng th\u1ea5p h\u01a1n -6.00D v\u00e0 c\u0169ng c\u00f3 th\u1ec3 \u0111i k\u00e8m v\u1edbi lo\u1ea1n th\u1ecb.<\/li>\n
    • C\u1eadn th\u1ecb ban \u0111\u00eam: th\u01b0\u1eddng x\u1ea3y ra v\u1ec1 ban \u0111\u00eam ho\u1eb7c khi c\u00f3 \u00e1nh s\u00e1ng y\u1ebfu. L\u00fac n\u00e0y do \u00e1nh s\u00e1ng y\u1ebfu n\u00ean c\u1ea3nh v\u1eadt c\u00f3 \u0111\u1ed9 t\u01b0\u01a1ng ph\u1ea3n kh\u00f4ng t\u1ed1t l\u00e0m cho m\u1eaft kh\u00f4ng c\u00f3 m\u1ed9t \u0111i\u1ec3m k\u00edch th\u00edch \u0111i\u1ec1u ti\u1ebft, vi\u1ec5n \u0111i\u1ec3m c\u1ee7a m\u1eaft s\u1ebd \u1edf kho\u1ea3ng c\u00e1ch trung gian ch\u1ee9 kh\u00f4ng \u1edf v\u00f4 c\u1ef1c nh\u01b0 trong \u0111i\u1ec1u ki\u1ec7n \u00e1nh s\u00e1ng \u0111\u1ee7.<\/li>\n
    • C\u1eadn th\u1ecb gi\u1ea3: xu\u1ea5t hi\u1ec7n khi m\u1eaft gia t\u0103ng \u0111i\u1ec1u ti\u1ebft hay do co qu\u1eafp c\u01a1 th\u1ec3 mi. \u0110\u00e2y l\u00e0 m\u1ed9t r\u1ed1i lo\u1ea1n ch\u1ee9c n\u0103ng, khi \u0111\u00f3 \u00e1nh s\u00e1ng song song t\u1eeb v\u00f4 c\u1ef1c s\u1ebd h\u1ed9i t\u1ee5 tr\u01b0\u1edbc v\u00f5ng m\u1ea1c gi\u1ed1ng nh\u01b0 c\u1eadn th\u1ecb th\u1eadt.<\/li>\n<\/ul>\n

      \"\"<\/p>\n

        \n
      • C\u1eadn th\u1ecb tho\u00e1i h\u00f3a: c\u1eadn th\u1ecb n\u1eb7ng th\u01b0\u1eddng k\u00e8m theo tho\u00e1i h\u00f3a b\u00e1n ph\u1ea7n sau c\u1ee7a nh\u00e3n c\u1ea7u do \u0111\u00f3 lo\u1ea1i c\u1eadn th\u1ecb n\u00e0y c\u00f2n \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 c\u1eadn th\u1ecb b\u1ec7nh l\u00fd. Nh\u1eefng tho\u00e1i h\u00f3a n\u00e0y c\u00f3 th\u1ec3 g\u00e2y ra nh\u1eefng b\u1ea5t th\u01b0\u1eddng v\u1ec1 m\u1eb7t ch\u1ee9c n\u0103ng c\u1ee7a th\u1ecb gi\u00e1c \u0111\u00f3 l\u00e0 gi\u1ea3m th\u1ecb l\u1ef1c t\u1ed1i \u0111a sau \u0111i\u1ec1u ch\u1ec9nh k\u00ednh hay khi\u1ebfm khuy\u1ebft th\u1ecb tr\u01b0\u1eddng. C\u00e1c bi\u1ebfn ch\u1ee9ng n\u1eb7ng c\u00f3 th\u1ec3 l\u00e0 bong v\u00f5ng m\u1ea1c ho\u1eb7c t\u0103ng nh\u00e3n \u00e1p.<\/li>\n
      • C\u1eadn th\u1ecb th\u1ee9 ph\u00e1t: g\u00e2y ra b\u1edfi m\u1ed9t s\u1ed1 lo\u1ea1i thu\u1ed1c, s\u1ef1 dao \u0111\u1ed9ng\u00a0 c\u1ee7a \u0111\u01b0\u1eddng huy\u1ebft trong b\u1ec7nh \u0111\u00e1i th\u00e1o \u0111\u01b0\u1eddng, \u0111\u1ee5c th\u1ec3 th\u1ee7y tinh, ho\u1eb7c do m\u1ed9t s\u1ed1 r\u1ed1i lo\u1ea1n kh\u00e1c. Lo\u1ea1i c\u1eadn th\u1ecb n\u00e0y th\u01b0\u1eddng ch\u1ec9 t\u1ed3n t\u1ea1i trong m\u1ed9t th\u1eddi gian nh\u1ea5t \u0111\u1ecbnh v\u00e0 th\u01b0\u1eddng c\u00f3 th\u1ec3 \u0111\u1ea3o ng\u01b0\u1ee3c \u0111\u01b0\u1ee3c.<\/li>\n<\/ul>\n
          \n
        1. Ph\u00e2n lo\u1ea1i theo m\u1ee9c \u0111\u1ed9 c\u1eadn th\u1ecb:<\/li>\n<\/ol>\n
            \n
          • C\u1eadn nh\u1eb9 (<-3.00D)<\/li>\n
          • C\u1eadn trung b\u00ecnh (-3.00 \u0111\u1ebfn -6.00D)<\/li>\n
          • C\u1eadn n\u1eb7ng (>-6.00D)<\/li>\n<\/ul>\n
              \n
            1. Ph\u00e2n lo\u1ea1i theo tu\u1ed5i kh\u1edfi ph\u00e1t:<\/li>\n<\/ol>\n
                \n
              • C\u1eadn th\u1ecb b\u1ea9m sinh ( xu\u1ea5t hi\u1ec7n khi sinh )<\/li>\n
              • C\u1eadn th\u1ecb xu\u1ea5t hi\u1ec7n khi tr\u1ebb ( t\u1eeb 6 \u0111\u1ebfn <20 tu\u1ed5i )<\/li>\n
              • C\u1eadn th\u1ecb khi tr\u01b0\u1edfng th\u00e0nh ( t\u1eeb 20 \u0111\u1ebfn 40 tu\u1ed5i )<\/li>\n
              • C\u1eadn th\u1ecb cu\u1ed1i giai \u0111o\u1ea1n tr\u01b0\u1edfng th\u00e0nh ( >40 tu\u1ed5i )<\/li>\n<\/ul>\n

                B. Nguy\u00ean nh\u00e2n c\u1eadn th\u1ecb<\/h4>\n
                  \n
                1. Nguy\u00ean nh\u00e2n c\u1ee7a c\u1eadn th\u1ecb:<\/li>\n<\/ol>\n

                  C\u1eadn th\u1ecb g\u00e2y ra b\u1edfi s\u1ef1 m\u1ea5t b\u00ecnh qu\u00e2n h\u00e0i h\u00f2a gi\u1eefa tr\u1ee5c tr\u01b0\u1edbc sau c\u1ee7a nhan c\u1ea7u v\u00e0 l\u1ef1c quang h\u1ecdc c\u1ee7a m\u1eaft khi\u1ebfn cho \u1ea3nh h\u1ed9i t\u1ee5 tr\u01b0\u1edbc v\u00f5ng m\u1ea1c.<\/p>\n

                  \"c\u1eadn<\/p>\n

                    \n
                  • Do tr\u1ee5c: tr\u1ee5c tr\u01b0\u1edbc sau c\u1ee7a nh\u00e3n c\u1ea7u qu\u00e1 d\u00e0i trong khi c\u00f4ng su\u1ea5t c\u1ee7a quang h\u1ec7 l\u00e0 b\u00ecnh th\u01b0\u1eddng.<\/li>\n
                  • Do c\u00f4ng su\u1ea5t c\u1ee7a quang h\u1ec7: c\u00f4ng su\u1ea5t kh\u00fac x\u1ea1 c\u1ee7a quang h\u1ec7 qu\u00e1 cao trong khi chi\u1ec1u d\u00e0i tr\u1ee5c nh\u00e3n c\u1ea7u l\u00e0 b\u00ecnh th\u01b0\u1eddng.<\/li>\n
                  • C\u1eadn th\u1ecb c\u00f2n c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c ph\u00e2n lo\u1ea1i chi ti\u1ebft h\u01a1n:<\/li>\n
                  • C\u1eadn th\u1ecb do chi\u1ebft su\u1ea5t: chi\u1ebft su\u1ea5t b\u1ea5t th\u01b0\u1eddng c\u1ee7a 1 ho\u1eb7c 2 m\u00f4i tr\u01b0\u1eddng trong su\u1ed1t c\u1ee7a m\u1eaft ( gi\u00e1c m\u1ea1c, th\u1ec3 th\u1ee7y tinh )<\/li>\n
                  • C\u1eadn th\u1ecb do \u0111\u1ed9 cong: do s\u1ef1 gia t\u0103ng b\u00e1n k\u00ednh cong c\u1ee7a gi\u00e1c m\u1ea1c ho\u1eb7c th\u1ec3 th\u1ee7y tinh<\/li>\n
                  • C\u1eadn th\u1ecb do \u0111\u1ed9 s\u00e2u ti\u1ec1n ph\u00f2ng: \u0111\u1ed9 s\u00e2u ti\u1ec1n ph\u00f2ng gi\u1ea3m l\u00e0m gia t\u0103ng c\u00f4ng su\u1ea5t c\u1ee7a quang h\u1ec7<\/li>\n<\/ul>\n

                    \u00a0 \u00a0 \u00a0 2. C\u00e1c y\u1ebfu t\u1ed1 nguy c\u01a1 d\u1eabn t\u1edbi c\u1eadn th\u1ecb<\/p>\n

                      \n
                    • Ti\u1ec1n s\u1eed c\u1eadn th\u1ecb trong gia \u0111\u00ecnh<\/li>\n<\/ul>\n

                      \"c\u1eadn<\/p>\n

                        \n
                      • T\u00ecnh tr\u1ea1ng c\u1eadn th\u1ecb ho\u1eb7c ch\u00ednh th\u1ecb ph\u00e1t hi\u1ec7n b\u1eb1ng ph\u01b0\u01a1ng ph\u00e1p soi b\u00f3ng \u0111\u1ed3ng t\u1eed kh\u00f4ng li\u1ec7t \u0111i\u1ec1u ti\u1ebft \u1edf tr\u1ebb tr\u01b0\u1edbc l\u1ee9a tu\u1ed5i \u0111i h\u1ecdc<\/li>\n
                      • T\u00ecnh tr\u1ea1ng ch\u00ednh th\u1ecb ho\u1eb7c vi\u1ec5n th\u1ecb <= +0.50D<\/li>\n
                      • Gi\u1ea3m ch\u1ee9c n\u0103ng \u0111i\u1ec1u ti\u1ebft ho\u1eb7c l\u00e1c \u1ea9n trong \u1edf th\u1ecb gi\u00e1c g\u1ea7n<\/li>\n
                      • Gi\u00e1c m\u1ea1c qu\u00e1 cong ho\u1eb7c ch\u1ec9 s\u1ed1 gi\u1eefa chi\u1ec1u d\u00e0i tr\u1ee5c tr\u01b0\u1edbc sau c\u1ee7a nh\u00e3n c\u1ea7u v\u00e0 \u0111\u1ed9 cong gi\u00e1c m\u1ea1c > 3,0<\/li>\n<\/ul>\n

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                        \n 5\/5 - (1 vote) <\/div>\n <\/div>","protected":false},"excerpt":{"rendered":"

                        Sorry, this entry is only available in Ti\u1ebfng Vi\u1ec7t. For the sake of viewer convenience, the content is shown below in the alternative language. You may click the link to switch the active language. C\u1eadn th\u1ecb l\u00e0 m\u1ed9t t\u1eadt kh\u00fac x\u1ea1 ph\u1ed5 bi\u1ebfn, b\u1ec7nh nh\u00e2n b\u1ecb gi\u1ea3m t\u1ea7m nh\u00ecn khi nh\u00ecn xa.\u00a0 Ng\u01b0\u1eddi b\u1ecb c\u1eadn […]<\/p>\n","protected":false},"author":1,"featured_media":3854,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[322,104],"tags":[253,266],"class_list":["post-3851","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-hieu-ve-doi-mat","category-tin-tuc","tag-benh-vien-mat-dnd","tag-can-thi"],"_links":{"self":[{"href":"https:\/\/matquocte.vn\/en\/wp-json\/wp\/v2\/posts\/3851","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/matquocte.vn\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/matquocte.vn\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/matquocte.vn\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/matquocte.vn\/en\/wp-json\/wp\/v2\/comments?post=3851"}],"version-history":[{"count":0,"href":"https:\/\/matquocte.vn\/en\/wp-json\/wp\/v2\/posts\/3851\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/matquocte.vn\/en\/wp-json\/wp\/v2\/media\/3854"}],"wp:attachment":[{"href":"https:\/\/matquocte.vn\/en\/wp-json\/wp\/v2\/media?parent=3851"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/matquocte.vn\/en\/wp-json\/wp\/v2\/categories?post=3851"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/matquocte.vn\/en\/wp-json\/wp\/v2\/tags?post=3851"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}