The lens in a human eye works to focus or refract light emitted from objects onto the retina.
A cataract is a clouding that develops in the clear crystalline lens of the eye, causing blurred vision. Early in the development of cataract, one can improve vision by adjusting the diopter for the glasses. However, as cataract progresses to cause vision loss, the diopter adjustment will not be of help. Currently, there is no medication that can prevent or treat cataract. The only effective treatment is surgery and intraocular lens implantation.
Established in 2003, the Cataract Surgery Centre was comprehensively equipped with the most advanced facilities and technologies. The Centre was renamed "Eye Surgery Centre" in 2012. All surgeries are performed by the
of the Department of Ophthalmology. During surgeries, there are several pain management options, among which General Anesthesia and Monitored Anesthesia Care are to be performed only by anesthesiologists. Monitored Anesthesia Care, chosen by one third of our patients, is a kind of pain management that can only be done in a hospital. There are also different types of implanted lens for patients to choose from. Other than traditional Monofocal Lens, toric lens, multifocal lens are also available so that one can treat cataract and correct refractive errors at the same time.
About cataract surgery:
What is Intra-ocular Lens?
An intraocular lens (IOL) is an implanted lens in the eye, usually replacing the extracted cataract, or as a form of refractive surgery to change the eye's optical power. It usually consists of a small plastic lens with plastic side struts, called haptics, to hold the lens in place within the capsular bag inside the eye. Nowadays, IOLs are made of flexible materials like Acrylic and Silicone. Most of them are fixed monofocal lenses matched to distance vision. However, other types are available, such as multifocal IOLs which provide the patient with multiple-focused vision at far and reading distance, and accommodating IOLs which provide the patient with some visual accommodation.
Monofocal Lens Implants
A Basic Intraocular Lens Implant is a fixed single focus lens that is designed to improve vision at just one distance, either far or near. The potential drawback is that after surgery you will probably need to wear glasses for near or far vision, even if you have never worn any glasses before surgery.
Many people have some degree of astigmatism (oval shaped cornea instead of the round shape), but a minor level of astigmatism is considered normal and requires no correction. For patients with moderate to high degrees of astigmatism, you can choose to have your astigmatism permanently reduced by having a Toric Lens Implant, but still, you will need to wear glasses for near or far vision.
Presbyopia-Correcting Lens Implants
Presbyopia is the natural age-related loss of flexibility of your lens to focus from far to near or vice versa, requiring you to use reading glasses, bifocals or multifocals spectacles. Moreover, cataract surgery itself also induces presbyopia since your own accommodating lens is removed.
Multifocal Lens Implants are manufactured with very fine rings with multiple powers. so you can see well at far and near focusing points. They do not require any muscular activity in your eyes for focusing, but a period of adjustment is necessary to learn to use this new optical system. The compromise is that there is a greater chance of seeing halos or rings around lights, glare and unclear vision as compared to a basic monofocal lens. Over time most people get accustomed to these disturbances and less prone to notice them, while others may continue to notice them long after surgery. You may have some difficulty distinguishing an object from a dark background, especially in areas with less light. You should take extra care when driving at night. Toric Multifocal Lens ar also available to correct astigmatism at the same time.
Causes of Cataract
Aging - It is the most common cause of cataract. The proteins within the lens of the eye begin to bind to each other and become stiffer with age, causing the lens to become opaque. So most frequently cataracts occur to senior patients.
The following are others factors that increase the risk of cataract in younger people:
- Excessive ultraviolet-light exposure
- Serious myopia
- Long-term use of steroid medicines
- Imbalance diet
- Long-term dehydration
- Trauma to the eye or eye surgery such as glaucoma surgery
- Congenital cataract
Prepare for the Surgery
Schedule Time off of Work
Most patients need 1-2 days off of work before being able to return to their usual work schedule. They may need to change their reading glasses after surgery if monofocal IOLs are used.
Patients should be accompanied by a responsible adult to accompany them home after the surgery.
Review Your Medications
If your doctor has instructed you to discontinue certain medications please do so. If your doctor has instructed you to begin taking other medications or use eye drops, please do so.
On the day of the surgery be sure to shower and wash your hair. Please do not wear makeup or cosmetics of any kind.
Eating & Drinking
Please do not drink alcoholic beverages for 24 hours prior to your surgery. Depending on your individual situation your doctor may ask you to fast for a few hours before coming to the surgery center. Follow their instructions.
Anesthesia Management During Cataract Surgery
Topical anesthesia is the most commonly used type of pain management in cataract surgery. Anesthetic eye drop is applied to prevent the patient from feeling any pain. Yet the patient can still move and feel mild pressure. Generally, no special preparation is needed for this kind of pain management, but the patient should avoid eating 4 hours prior to the surgery.
Other than anesthetic eye drop, local anesthetic is injected in the peri-orbital area. The patient would not feel any pain and his muscle will be relaxed. Generally, no special preparation is needed for this kind of pain management, but the patient should avoid eating 4 hours prior to the surgery.
Monitored Anesthesia Care
This type of pain management can only be done in a hospital by anesthesiologists. The anesthetic dosage is lower than that of general anesthesia, but enough to make a patient fall asleep. The patient's cardiopulmonary functions are monitored by the anesthesiologists the whole time. If a patient finds it difficult to relax or has physical conditions that require a close monitor on his cardiopulmonary functions, this pain management can be considered. Generally, no special preparation is needed for this kind of pain management, but the patient should avoid eating 6 hours prior to the surgery.
This type of pain management can only be done in a hospital by anesthesiologists. The anesthetic dosage is enough to make a patient lose consciousness and feel no pain. The patient may be connected to a respirator that aids him breathing. The patient's cardiopulmonary functions are monitored by the anesthesiologists the whole time. Generally, no special preparation is needed for this kind of pain management, but the patient should avoid eating 6 hours prior to the surgery.
Post-operative Care & After Surgery
Risk and Complication
The surgery is usually performed under topical and local anaesthesia or monitored anaesthetic care (MAC).
- A micro incision is made in the cornea.
- Part of the anterior capsule of the natural lens
will be removed.
- A high-frequency ultrasound probe will be used to break up the lens and the fragments will be taken out through the small corneal incision.
- A foldable intraocular lens will be implanted.
- The small incision may need microscopic
stitches for closure sometimes.
- Femtosecond Laser may be used to assist the
procedure, such as corneal incision, capsulotomy, lens fragmentation and astigmatism correction.
After the Procedure
Infection or inflammation.
- Intraocular bleeding/ iris trauma.
- Subconjunctival haemorrhage.
- Posterior capsule tear and leakage of vitreous humour that may need vitrectomy surgery.
- Increased intraocular pressure.
- Photophobia/foreign body sensation/dry eyes.
- Corneal edema/ decompensation
- Floaters/ retinal detachment/ macular oedema.
- Cataract fragments remained in the eye.
- Decentration or fogging of the intraocular lens that may need centering, removal or re-implantation of the lens.
- Post-surgery refraction may not reach the target as planned, and may require further surgery, corrective lenses or readings glasses.
- Change of planned model of intraocular lens/ additional surgeries to treat complications.
- Posterior capsular opacity that may need laser surgical treatment.
Follow up Examination
Keep the eye shield on for protection for 1- 2 weeks during sleep.
- Please take medication or instill eye drops as instructed by your doctor.
- Avoid soap, shampoo or tap water getting into your eyes for 1 week.
- Do not use eye make-up and swim for 1 month after surgery.
- No rubbing of the operated eye.
- Use sunglasses when you are outdoors for 1 month to prevent foreign bodies and irritation of ultraviolet light.
- Avoid heavy lifting, straining and excessive physical exertion.
- Take more fruit and vegetables to avoid constipation.
- Avoid crowded or polluted places to prevent trauma and infection to the wound.
You must return to your doctor for follow up as instructed.
1 day after surgery
An experienced ophthalmologist can diagnose cataract clinically during regular eye check-up including visual acuity test
(Patients will read eye charts from a distance for the test.)
(to determine the pressure in the eye) and slit lamp examination.
Pupil dilation permits the retina, eye chambers, macular and optic nerves to be examined for signs of disease.
When a patient is diagnosed with cataract, the length of eyeballs and the thickness of cornea
will be measured with Ultrasound
so the doctor can choose an appropriate lens implant for the patient.
Frequently Asked Questions (FAQ)
How urgent is a cataract surgery? Can it wait?
A cataract usually starts very mild and practically unnoticeable but gradually becomes cloudier. Early cataract does not affect vision. Once your vision and living standard are notably affected, cataract surgery can be considered. Very mature cataract can cause glaucoma or uveitis.
Can cataract recur?
Once a cataract is removed, it will not recur. However, a small percentage of cataract-surgery patients will develop some clouding of the "capsule" in which the artificial lens is placed. If this clouding affects a patient's vision, it can be quickly and safely lasered away by an eye surgeon in just a matter of minutes.
What happens if a patient chooses not to undergo cataract surgery?
If left untreated, cataract can lead to blindness.
Will I feel the lens inside my eye? How long can the lens stay in my eyes?
No. There are no nerve cells in the capsule where the lens is implanted, so you will not feel it. The lens is placed permanently in your eye and will not "wear out".
Do I need to wear glasses after the surgery? Do I wear the same glasses as now?
In general, patients who choose to have mono-focal lens implants will be dependent on glasses either for distant or near correction. Patients who choose to have multifocal lens implants will not need glasses for daily works. Some will need glasses for computer or other mid-distant duties.