Intravitreal Injection
You have been given this leaflet because your eye doctor recommends that you receive an injection to treat your eye condition. This booklet explains the procedure, risks and benefits, and how to care for your eyes after the procedure.
What is an intravitreal injection?
This is an injection into the vitreous cavity of the eye. Injections are used to deliver medication to treat certain conditions which cannot be treated by eye drops or tablets.
Why do I need an intravitreal injection?
Your doctor may recommend it to treat certain conditions where abnormal blood vessels may leak or bleed, causing damage to the retina. When leakage and bleeding occurs at the macula (centre part of the retina), patients may lose central vision.
Common conditions where this may occur include:
Myopic choroidal neovascularisation
What will be injected and how does it work?
Common medications that are injected include: Anti-vascular endothelial growth factor (anti-VEGF): VEGF is a locally produced protein that results in the growth of abnormal new blood vessels. These new blood vessels leak and bleed easily. Anti-VEGF stops these blood vessels from growing and controls the leakage of fluid and blood, therefore preserving vision.
Steroids: Inflammation can cause blood vessels to be leaky, tissue damage and vision loss. Steroids reduce inflammation and prevent tissue damage in certain conditions.
Your ophthalmologist will assess you and advise you on the appropriate treatment based on scientific evidence, local, and international best practice.
How is the treatment given?
The injection is delivered either by a doctor or a registered nurse practitioner who is trained and accredited to do so. The injection is conducted in the treatment room with you lying on an examination chair. The whole procedure takes 10 minutes although the injection itself takes less than 5 seconds.
You may experience some discomfort, similar to having blood taken from your arm. You do not need to fast before the procedure. You can expect the following to occur although there may be minor variations in the sequence:
• Local anaesthetic drops will be applied to numb your eye and minimise discomfort
• Your eyelids and surface of the eye will be cleaned with an antiseptic solution to reduce the risk of infections
• A speculum (small clip) will be inserted to keep your eyelids open and eyelashes away during the injection
• More antiseptic and anaesthetic drops will be applied to further numb your eye
• The injection site is accurately measured
• Your eye is stabilised with forceps or a cotton bud
Illustration demonstrating a fine needle entering the vitreous cavity during intravitreal injection.
• The medication is injected into your eye with a very fine needle
• Your optic nerve function will be assessed by checking if you are able count fingers
• In some cases, the doctor may decide to release some fluid from the eye if there are concerns about high pressures in the eye during the procedure
What happens after the treatment?
After the procedure you may have to wait to have your eye pressure checked if advised by the doctor. Before you leave, you will be given the date for your next appointment. Most patients require regular injections, depending on the condition you have, the type of medication injected and the treatment response. Some patients need injections every 4 weeks, but some only require it every 16-20 weeks to keep their eye condition stable. You will also be reviewed at regular intervals where your doctor will decide if further treatment is needed, or if you only need to be monitored.
Who should not be treated with anti-VEGF?
You should not be given antiVEGF if you have any of the following conditions:
• Allergy to anti-VEGF or any of its ingredients
• If you have an infection in or around either eye or active infection anywhere in your body
• If you are trying to become pregnant, are already pregnant, or are breastfeeding
Anti-VEGF should be used with caution in patients with the following conditions:
• If you have had a heart attack or a stroke in the last three months.
• If you have uncontrolled angina (chest pain) or uncontrolled high blood pressure.
Please inform the doctor if there are any changes in your medical condition.
What are the risks with these injections?
As with any medical procedure, there are small risks related to intravitreal injections. Most complications that might occur are from the injection itself, rather than the drug. For most patients, the benefit of the treatment outweighs the risks involved.
The following are the potential major risks and side effects of intravitreal injections. Most of these risks are rare. Significant loss of vision due to this treatment is extremely uncommon.
• Endophthalmitis (serious eye infection and blindness occurring in one in 2,000 cases)
• Retinal detachment
• Elevated eye pressure
• Bleeding in the eye
• Inflammation
• Cataract
Some common side effects include:
• Red eye or subconjunctival haemorrhage. This is very common and harmless and occurs at the point of needle entry. Your eyes will look very red, but this is harmless and will resolve on its own after 10-14 days
• Sore and gritty eye (this is often due to the antiseptic used and lasts for a few days). This is easily treated with lubricant (artificial tears) eye drops
• Floaters (often for 1-2 days, but if they persist or worsen after that, return within a day)
• Flashing lights or swirls of light (this occurs immediately after the injection and lasts for a few seconds only)
In addition to the above, systemic risks like heart attack, stroke and other vascular events have been reported with systemic (injected into your veins) anti VEGF administration. The dose used for eye injections is about 1000 times lower than the systemic dose.
Injecting this tiny amount of antiVEGF into the eye has not been shown to increase the risk of strokes or heart attacks, except in patients who have had a stroke or heart attack recently.
Please inform your doctor if you had suffered from heart attack, angina or stroke in the last 3 months. If you have any concerns, please discuss with your doctor.
Can other medicines or food affect anti-VEGF treatments? There are no food restrictions, however it is always good to eat healthy. Take all your regular medications as you normally do every day, including blood pressure medication.
Do I need to take any special precautions?
It is recommended that you avoid getting water into your eye for 2 days and avoid swimming for 5 days. You can travel, but if you develop any of the problems described below, please consult an eye doctor urgently.
What to do in an emergency?
Please walk in to KTPH C42 Eye Clinic during office hours if you experience the following:
• Pain, redness, swelling and sensitivity to light worsening in the days after the injection. This may indicate an infection and normally occurs within 1 week
• Excessive discharge from the eye
• Sudden deterioration of vision
• Flashes of lights and/or new floaters that continue or worsen from the day or week after the injection
Office hours: Monday – Friday: 8.30am – 4:00pm *Closed on Saturdays, Sundays and Public Holidays.
Outside of office hours, if you experience any of the above, you MUST seek treatment without delay at Acute & Emergency Care (A&E) Centre at Tower A Level 1, Khoo Teck Puat Hospital. Do not wait until the next day. Seeking advice early can make a big difference to your vision.
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Yishun Health is a network of medical institutions and health facilities of the National Healthcare Group in the north of Singapore. It comprises Khoo Teck Puat Hospital, Yishun Community Hospital and community extensions such as Admiralty Medical Centre and Wellness Kampung. Khoo Teck Puat Hospital • (65) 6555 8000 • www.ktph.com.sg Yishun Community Hospital • (65) 6807 8800 • www.yishuncommunityhospital.com.sg
The information is correct at the time of printing and subject to revision without further notice.