• Eye Diseases

    Many eye problems come with advancing age. Presbyopic, the need for reading glasses, is inevitable. Other examples include cataract, glaucoma, age related macular degeneration, diabetic retinopathy.

    The risks of having eye diseases increase with a positive family history, hypertension, cardiovascular diseases, diabetes, smoking and alcohol abuse.

    People over age 55 years are recommended to have regular eye check up every one or two years in order to initiate treatment during the early stages of the disease.

  • Cataract

    What is cataract?

    An opacified lens in the eye is a cataract. The eye is similar to a camera, light rays are focused by the lens onto the retina in order to form a sharp image. When a lens becomes opacified, the image formed will be blurred. The commonest cause of cataract is aging; other causes include diabetes, trauma, inflammation and congenital.


    Symptoms of cataract

    Most patients with cataracts will notice gradual blurring of vision. Others symptoms include glare under bright light, double vision in one eye, frequent change of glasses prescriptions, reduced dependence on reading glasses. The eye is not painful nor red unless in advanced cases with complications.


    Can drugs prevent or treat cataracts?

    While some medications may slow down cataract development, in order to prevent cataract formation one should avoid strong ultra-violet light exposure by the use of sunglasses.


    Cataract extraction surgery

    Surgery is the only treatment for cataract, and over 95% of patients can restore their vision after surgery. After the removal of cataract, an individualised intraocular lens implant will be fitted in place for best visual outcome. Usually this microscopic surgery is performed under local anesthesia and lasts less than 30 minutes. There is no need to stay in the hospital after surgery. Most cataract are removed by ultrasound phacoemulsification. This minimally invasive approach ensures faster recovery due to a small wound size.


    Does the cataract need to be mature before operation?

    No, this approach is outdated. As the outcome for cataract surgery is excellent nowadays, the timing is based on visual needs. When eyesight has effected the activities of daily living, then cataract surgery should be considered.


    What is posterior capsular opacity?

    Some patients experience visual deterioration a few years after cataract surgery. When a cataract was removed, its transparent capsule was left intact in order to support the intraocular lens implant. In some cases, the capsule may become opacified or scarred with time and vision is then affected. The opacified capsule can be treated with a simple laser procedure call Nd:Yag capsulotomy, after which lights rays can again be focused sharply on the retina forming a clear image.

  • Glaucoma

    Normal

    Glaucoma

    Glaucoma is usually caused by elevated intraocular pressure leading to visual loss.

    When the drainage channels are blocked, fluid trapped inside the eye leads to elevated intraocular pressure. Such pressure damages the optic nerve fibres causing irreversible visual deterioration and ultimately blindness.

    Normal

    Glaucoma

    • Acute Glaucoma:Acute glaucoma occurs when the aqueous drainage channels are blocked within a short period of time. Pressure inside the eye quickly builds up due to the trapped fluid. Symptoms may include aching pain in the eye, headache, blurring of vision, halo, nausea and vomitting. The immediate treatment is to reduce the intraocular pressure, after which treatment will be directed to manage complications such as recurrence and chronic glaucoma. The other eye will require medication or laser therapy to prevent similar glaucoma attack.
    • Chronic Glaucoma
      • This is the commonest type of glaucoma. At the early stage, only the peripheral visual field is affected, hence it is frequently overlooked. If it is uncontrolled, visual loss will eventually affect central vision.
      • The risk of chronic glaucoma rises with age, it usually develops in patients over the age of 35 and sometimes runs in the family.
      • During the early stages, patients with chronic glaucoma do not have any symptoms. When the intraocular pressures becomes high, patients may experience some aching in the eye with headache, hazy vision and halo when looking at lights.
      • The diagnosis of glaucoma requires clinical examination of the optic nerve heads, visual fields and intraocular pressures.
      • Chronic glaucoma can be treated and controlled. As it cannot be eradicated, observation and treatment are required for life. Permanent visual damage can be avoided if glaucoma is detected and treated early.
    • Secondary Glaucoma : Secondary glaucoma occurs in relation to other eye diseases, such as iritis, eye injury, mature cataract, prolonged steroid usage and diabetes. Treatments of both glaucoma and the underlying ocular diseases are required.
    • Congenital Glaucoma : This kind of glaucoma is found in newborn. Symptoms may include watery red eyes, high sensitivity to light, squint and cloudy large corneas. Early surgery is mandatory.
  • Floaters

    Normal

    Floaters

    What are floaters?

    Floaters are sometimes described as seeing black spots. While they can be caused by different diseases, the majority is due to vitreous condensation. The vitreous body is a transparent gel - like substance filling up the space between the lens and the retina; light rays pass through the vitreous and project onto the retina. With advancing age, the vitreous body contracts and detaches itself from the surface of the retina. Additionally the vitreous body may develop opacities during this condensation process which form shadows onto the retina. These can be seen as dots, lines, small patches or spider webs. On the other hand, vision threatening diseases such as retinal tear, retinal detachment, vitreous haemorrhage, uveitis can present with similar floaters. Therefore prompt examination by an experienced ophthalmologist is recommended.


    Can floaters be cured?

    Though most floaters are benign and may become less apparent overtime, there are some medications that may reduce the vitreous condensations.

  • Age Related Macular Degeneration

    What is maculopathy?

    The central region of the retina is the macula. When there is pathological changes in the macula, central vision will be distorted and blurred. In maculopathy, fine vision and reading will be affected most, while peripheral vision is preserved. Frequently such changes are related to ageing, where it is known as age related macular degeneration. Age related macular degeneration usually occurs after the age of 50, and it is a major cause of permanent blindness after the age of 60. At the early stages, the symptoms experienced may not be very obvious. If the maculopathy is the educative type however, vision may deteriorate rapidly during the two years after diagnosis, leading to blindness.


    Two types of age related macular degeneration

    1. Dry type

    • Commoner, with lesser visual deterioration
    • Yellow white druses spots in the macula
    • Slow progression
    • May worsen and develop wet type

    2. Wet type (exudative)

    • Abnormal blood vessels grow within the macula region, where
    • Exudation and
    • Blood may accumulate
    • Severe worsening of vision, usually irreversible

    What are the causes of age related macular degeneration?

    It is usually found in patients over the age of 50, more with advancing age, but no sexual predominance. The retinal degenerates with thinning causing deterioration of macular function. Possible factors include familial history, dietary habit, smoking, exposure to excessive radiation, cardiovascular diseases and anxiety.


    How to use the Amsler Grid

    • Under adequate lighting, place the Grid at 30 cm distance from the eyes.
    • Wear adequate spectacle correction or reading glasses if required.
    • With the left eye covered, fixate the right eye onto the central spot on the grid.While fixating at the central spot, note if there is any distortions or defects with the grid.
    • Repeat with the left eye.
    • Any distortion may an early warning sign and must be checked by the doctor quickly.

    Treatment of maculopathy

    One of the treatment is by photodynamic therapy. A photosensitizing agent is injected which will attach onto the abnormal blood vessels. A low energy laser is then applied locally onto the affected area, and those treated abnormal vessels will stop growing and leaking. The advantages are that there is no damage to the retina and there is no scar formation.

    • Regular self examination using the Amsler Grid.
    • Flourescein Angiography Flourescein angiography examines the retinal blood vessels by taking photographic images of the vessels at different time intervals after an injection of dye.

    Anti-VEGF injection have been shown to be effective in treating AMD. These injections are usually administered in our day surgery centre, while the injections are given in a sterile and clear setting. Monthly injection schedules are usually tailored-made to the patients conditions in order to achieve the maximum benefits of the anti-VEGF therapy.

  • Retinal Detachment

    Normal

    Retinal Detachment

    What is retinal detachment?

    視網膜脫落

    When the vitreous humour contracts, it may cause breaks in the retina. When fluid seeps under the retina through these retinal breaks, the retina will become detached.


    What are the signs for retinal detachment?

    During the acute phase of a retinal detachment, the patient may experience:

    • An increase in floaters
    • Seeing flashes of light, development of a shadow like a curtain in the peripheral vision
    • Blurring of vision

    Who are more at risk of retinal detachment?

    • Those with thinning of the retina.
    • High myopia (Short sightedness).
    • Positive family history.
    • History of trauma to the eye or head.

    Can retinal detachment be prevented?

    Retinal detachment cannot be prevented by medication. If retinal breaks are recognised early by an ophthalmologist through examination with pupil dilation, laser barrier or cryotherapy may be applied to seal off such breaks, thereby prevent the development of retinal detachment. Therefore the most effective prevention is to be aware of the warning signs such as floaters and light flashes, and seek the help of an ophthalmologist promptly for a complete eye examination. For those with severe short-sightedness, it is advisable to avoid contact sports and have regular check ups.


    Can retinal detachment be repaired?

    Retinal detachment is a serious situation, and surgery to repair retinal detachment is complicated. The success rate may be up to 90%, but multiple surgeries are at times required. There are basically two categories of surgeries: by the insertion of an explants onto the sclera in the form of a silicone band or buckle then application of cryotherapy to the retinal breaks, or by pars plana vitrectomy where the laser is applied to seal off the retinal breaks and gas may be injected in place of the vitreous removed in order to flatten the retina.

  • 兒童弱視眼

    弱視眼的定義

    • 弱視眼的定義是眼睛本身沒有可見的病變,或可見到的病變經已得到治療,但是視力卻未能達到正常。
    • 初生嬰兒的眼睛具備了視力和視覺所需要的構造,但視力祗有成人的三至四成左右。
    • 在視力發展的過程中,腦視力中樞需要接受適當視覺訊息的刺激,才能完整發育。若在這段重要的期間,光線未能順利進入眼球內,或光線和視覺訊息進入眼球後,未能在視網膜上清晰地聚焦,造成不足夠的視覺刺激,便會阻礙視力正常的發育而導致弱視。
    • 視力發展最重要和最迅速的時期是出生後至三,四歲的期間。
    • 三、四歲時,幼兒的視力已達到成年人的水平。
    • 八、九歲時,視力發育已完成而不易改變。
    • 兒童患弱視和成年人患弱視的最大分別是若果前者在八歲之前發覺,找出導致弱視的原因而得以適當的治療,弱視是有機會和可以醫治好的
    • 八歲以後才發覺,醫治好的機會便大大減少,而在成年時才發現患弱視的話,是無法醫治的。

    造成兒童弱視最常見的原因有下列三大類:

    • 斜視
    • 混濁的眼睛介質
    • 屈光異常

    斜視

    • 斜視是指兩隻眼睛位置不正,可分為偏內,偏外和上下不正常。
    • 絕大多數兒童時期的斜視屬於共同性斜視,即不論向何方注視,兩眼不平行關係始終保持恆定的。
    • 因為兩眼視線不相平行,會呈現複視(即一個東西看成兩個東西),斜視的兒童為了避免複視的情況,他們的大腦會主動否定或忽視來自斜視眼睛的影像,進而抑制這些影像.假以時日,複視便會消失,不過雙眼共視的機能亦無法產生,立體感亦會喪失。
    • 單眼斜視的兒童,因為來自斜視眼睛的影像長期受到抑制,會變成弱視。

    斜視的類型 斜視可分五大類型:

    1. 內斜視

    • 一般俗稱為「鬥雞眼」,即眼睛的位置向內偏斜,分為先天性和後天性。
    • 先天性的內斜視出世後便經已發覺,通常需要外科手術來矯正斜視。
    • 後天性的內斜視通常在二至三歲左右開始發生,有一部份是由於遠視而導致的,在配戴更正遠視度數的眼鏡後,斜視便得以完全更正,或偏斜視的程度得以減少。第一類的兒童,祗需要經常作視力檢查和遠視度數的量度。第二類的兒童在醫治好因為斜視而引起的弱視後,便需要外科手術矯正戴遠視眼鏡時還剩餘的斜視。
    • 還有其他後天性的內斜視和遠視沒有關係,這些兒童在醫治好因為斜視而引起的弱視後,需要接受矯正斜視的外科手術。

    2. 外斜視

    眼睛的位置向外偏斜,可分為間歇性和持續性,通常在三至四歲在右發生。 間歇性的外斜視,因為祗是間中才有外斜視,導致弱視的機會較低,患者亦有較佳的雙眼共視功能和立體感。 這些兒童眼睛的位置經常是維持在正常的眼位,只是偶然因為強烈的陽光刺激眼睛、或疲勞、或不經心的時候,外斜視的眼位才會表現出來。 有一部份間歇性外斜視會發展成為持續性外斜視。 外斜視兒童的弱視情況普遍不太嚴重,有一部份需要配戴更正近視度數的眼鏡。 外科手術矯正外斜視的效果很有效和理想。

    3. 上,下斜視(垂直性斜視)

    • 即眼位向上或向下偏斜,比較少見。
    • 這些兒童為了避免因為垂直性斜視而引起的複視,通常喜歡將頭部歪斜在某一方向視物。

    4. 假性斜視

    • 有些兒童因為內眥贅皮較為寬厚,或是鼻樑較寬定扁平,阻擋著眼球內側眼白的部份,引致"內斜視"的外觀。
    • 有些兒童兩隻眼睛之間的距離比較長,形成"外斜視"的外觀。
    • 這些兒童眼睛的位置沒有偏斜,所以不會有因為斜視而形成的弱視和視覺功能的障礙。

    5. 傾向性斜視

    • 大部份人士(約百分之六十至七十)是有斜外、或斜內的傾向。
    • 當他們在雙眼一齊觀看景物的時候,眼睛的位置是正常,而沒有偏斜的。
    • 他們並有弱視或因為斜視而引起的視覺功能異常。
    • 當他們身體不舒適或過份疲勞的時候,控制雙眼不偏斜的能力較弱,斜視有可能變成明顯,會看到重影。但是當精神回復的時候,他們可以控制雙眼不偏斜,複視亦會消失。

    總括來說,當發現兒童患有明顯的斜視或懷疑子女有斜視,家長應該帶兒童到眼科醫生作詳細檢查。

    斜視的治療是首先醫治好因為斜視而導致的弱視,然後才做矯正斜視的外科手術。

    斜視若果沒有及早治療,除了會造成弱視外,立體感和雙眼共視的視覺機能亦會喪失,造成兒童一生的視力和視覺的缺陷。


    混濁的眼睛介質

    • 這些情況較為少見,包括先天性白內障眼角膜混濁、玻璃體混濁、先天性上眼瞼下垂、眼睛外傷、出血或後天性眼病等,會干擾光線到達視網膜,使景物無法在視網膜上清晰地形成影像,導致弱視。
    • 視網膜脫落,視網膜出血,也可造成弱視。

    屈光異常

    • 如果我們把眼球比作一具照相機,那麼視網膜就好比照相機內的感光菲林,而眼角膜和晶體就好比照相機內的鏡頭組合,能夠把光線屈折,從而將景物的影像聚焦在視網膜之上,使我們能夠清晰看見景物。
    • 屈光異常可分為近視、遠視、或/和散光。
    • 近視是由於眼角膜和晶狀體的鏡頭組合將景物的影像聚焦在視網膜之前。
    • 遠視是由於景物的影像被聚焦在視網膜之後,投射到視網膜之上的影像變得模糊。
    • 散光是由於景物的影像不能夠一齊全部聚焦在視網膜之上,使景物的影像變得模糊。
    • 屈光異常若在兒童視力還在發育期間發生,由於景物的光線未能在視網膜上聚焦,造成不足夠視覺訊息的刺激,會造成弱視。
    • 單眼屈光異常的兒童,患弱視的情況更為嚴重,因為他們會選擇使用正常的眼睛觀看景物,導致屈光異常眼睛的視力發育停頓或不正常。

    眼球的結構

    正常屈光

    近視

    遠視


    如何知道兒童患有弱視?

    • 如果是因為斜視、上眼臉下垂、眼角膜混濁、或先天性白內障而引起的弱視,因為致病原因的外觀較明顯,容易為父母發現,通常能及早就醫。
    • 屈光異常如遠視、近視、散光、或外觀不明顯的致病原因,一般一個未懂事的小孩子,可能不曉得告訴家長他看東西不清楚,會導致延遲就醫。
    • 家長應該注意子女日常觀看事物、景物的習慣,例如孩子是否總是喜歡瞇著眼睛、或側著頭看東西,看電視時喜歡靠近螢光幕,或有一些異常的習慣如不停眨眼、搓眼等。如果有這些情況,應該儘早帶孩子看眼科醫生作眼睛檢查。
    • 單眼屈光性弱視的兒童,是最不容易被察覺出來,因為他們另外一隻眼睛視力正常,所以很難發現不良視力的弱視。

    怎樣治療弱視?

    • 弱視治療的原則,最重要是在視力,視覺發育未完成之前,強迫弱視眼睛的使用,進而促進弱視眼睛的視力。
    • 最常用的方法是遮眼治療,就是把正常的眼睛遮蓋,迫使弱視的眼睛多使用。
    • 斜視的兒童通常需要首先醫治弱視,到弱視醫治好或穩定之後,才安排矯正眼睛位置的外科手術。
    • 手術後還需要跟進的檢查,以確定原本斜視的眼睛維持良好的視力和保持眼睛位置不偏斜.個別的情況,可能有必要作多過一次矯正眼睛位置的外科手術。
    • 屈光性弱視的兒童,必需大部份時間配戴更正屈光錯誤度數的眼鏡.若果配戴眼鏡後視力依然沒有改善,則需要加上遮眼的治療。
    • 單眼弱視的兒童,遮眼的治療是絕對必須的。
    • 一般家長因為不瞭解配戴眼鏡對醫治弱視的重要,不接受讓孩子在幼小的年紀便已配戴眼鏡,其實配戴眼鏡對一個八歲以下的兒童而言,有兩個原因:
      • 配戴合適度數的眼鏡,能使孩子的視力清晰,有助於他們的學習。
      • 屈光性弱視的兒童,配戴眼鏡時,景物的光線才能清晰地在視網膜止聚焦,使高品質的視覺訊息能夠輸入視覺的腦神經組織,進而喚醒視覺腦細胞,刺激視力和視覺的發育令視力改善。
    • 患有混濁眼睛介質,或先天性上眼臉下垂等的兒童,眼科醫生會根據個別的眼疾作適當的藥物或外科手術的治療,然後積極地醫治弱視。
    • 弱視的治療和訓練並不是一朝一夕便能達成的,經常需要數個月,甚至幾年的時間。

    怎樣預防弱視?

    • 弱視是否能治癒,視乎發現弱視時的年齡和發現時弱視的深淺。
    • 人類視力和視覺發育最迅速的時期為出生後至四,五歲之間,在這段時期發現弱視而作適當的治療,效果是理想的。
    • 視力和視覺發育在八歲已經完畢,如果在此時才發現弱視,治癒弱視的成數較低。
    • 患弱視的兒童若果在二、三歲時發現患有弱視,治癒弱視的機會很大,而發現時弱視的程度越淺越好。
    • 斜視性和屈光性弱視,比因為混濁的眼睛介質如先天性白內障而導致的弱視較為容易治療。
    • 預防弱視之道是如果兒童有明顯的症狀,或被懷疑患有弱視,父母應該儘快帶孩子看眼科醫生作詳細的檢查。
    • 有些弱視是沒有明顯的症狀,所以最佳的預防方法是孩子在三週歲的時候,讓眼科醫生替孩子作視力和眼睛的檢驗。