青光眼的類別和病徵

常見的青光眼大致可以分成兩大類別 : 原發性青光眼和繼發性青光眼，其病徵狀詳述如下 :

i) 原發性青光眼

原發性青光眼最為常見，病發率佔全民的1%, 尤以四十歲以上人仕佔當中的2.5%，患者多數是雙眼發病，其病發原因尚不十分清楚，部份與遺傳有關。根據其病發之急緩，可以分為急性和慢性兩種 :

(a) 急性青光眼

通常患者會突然病發，在一日之間視力大減，並會出現以下病狀:看燈光時會出現彩虹圈、眼紅、角膜混濁、眼睛劇痛、頭痛、噁心及嘔吐等情況。

(b) 慢性青光眼

大部份患者在初期的時候都沒有明顯的病徵，所以很難發現巳經患上青光眼，通常由眼科醫生進行例行檢查時，才會發現患上青光眼；其中小部份患者會覺得視力減退。

到病患後期的患者，其視神經已經有一定程度的損壞，患者的視野範圍會日漸變窄；最後，患者除視野中心以外，甚麼都看不見，好像拿著竹筒看東西一樣，而且走路的時候會經常撞著桌椅等，物件視力亦會漸漸減退，直至完全失明為止。

參考資料:  《長者護眼常識100分》小冊子

以上所提供的資訊僅作為教育及參考用途，如果你有任何醫療問題，應向自己的眼科醫生查詢，而不應單倚賴以上提供的資料。

Nearsightedness (Myopia) - Surgery

Several types of surgery for nearsightedness (myopia) can change the shape of the cornea and refocus light directly on the retina. But surgery cannot correct pathological myopia.

The goal of surgery is to allow people who are nearsighted to see clearly without corrective lenses or to be less dependent on corrective lenses. Most doctors consider 20/40 vision or better after surgery a satisfactory result. People with 20/40 vision or better are allowed to drive a car without corrective lenses. Overall, most people who have surgery achieve 20/40 vision or better after surgery.

Laser surgeries include:

• LASIK (laser in-situ keratomileusis), which is currently the most commonly used corrective surgery for nearsightedness. LASIK has a high success rate and low complication rate for low to moderate nearsightedness. It may also be used to correct more severe nearsightedness. In general, it requires less healing time, is less painful, and offers a faster visual recovery than photorefractive keratectomy (PRK).

• PRK (photorefractive keratectomy), LASEK (laser epithelial keratomileusis), and epi-LASIK (epithelial laser in-situ keratomileusis), which are similar surgeries. They are another type of corrective surgery for nearsightedness that is used frequently. Like LASIK, these surgeries have high success rates and low complication rates for low to moderate nearsightedness. They may be used instead of radial keratotomy (RK) to correct severe myopia.

Reference: www.webmd.com, www.eye123.com.hk

The information provided aims to provide educational purpose, if you have the described conditions as above, please consult your ophthalmologist.