Health Resources

Cornea and External Eye Diseases


What is Blepharitis/Meibomitis?

Blepharitis is a general term that describes inflammation of the eyelids. It may be due to bacterial colonisation of the lid margins, inflammation of the oil glands on eyelid margins, or both. The upper and lower eyelid margins contain a row of oil glands that produce oil, coating the tear surface to reduce evaporation.

What Will I Feel if I Have This Condition?

You may have the following symptoms:
  • Itch
  • Burning sensation
  • Redness and/or swelling of the eyelid margin
  • Eye redness
  • Foreign body sensation (eg, feeling like there is sand in your eyes)

How Can It Be Treated?

While it is a long-term issue that cannot be completely eradicated, it can be controlled through the following measures: 

Lid hygiene

Commercial eyelid cleaning solutions are available and can be used to clean the eyelid margins and eyelashes, up to twice a day. Alternatively, diluted baby shampoo (one part baby shampoo to ten parts warm water) can be used. Dip a cotton bud in the solution to clean the eyelids, removing any crust. Rinse off the shampoo with a wash cloth.

Warm compress

Run a clean face towel, under hot water and apply to the eyes to warm the eyelids. This increases the temperature of the oil in the glands, liquefying the oil. Thereafter, massage the eyelids to aid the expression of this oily material. 


As increased tear evaporation leads to dry eyes, artificial tears are used to reduce discomfort. Ointment-based lubricants tend to keep the surface of the eye moist for a longer duration, but may induce blurred vision. These ointments are particularly useful when applied at night. 


Topical antibiotics can be applied to the eyelids to reduce bacterial load and, hence, inflammation. Additionally, your Ophthalmologist may opt for oral antibiotics to reduce bacterial load and inflammation of the eyelids. 

Anti-inflammatory eye drops

In severe cases, anti-inflammatory eye drops containing steroid may be necessary to reduce inflammation, preventing excessive damage to the surface of the cornea.

Essential fatty acids

Supplements containing essential fatty acids have been recommended to alleviate eye irritation symptoms and promote a healthy tear film on the surface of the eye. 

Do note that not all these interventions may be needed at the same time. Your doctor will perform an assessment and formulate a treatment method based on your specific needs.

Contact Lens Associated Problems

What are Contact Lenses?

Contact lenses are thin plastic lenses that are placed on the tear film at the front of your eye. When used with care and proper lens wear habits, they offer a safe and effective means of correcting vision.

What Are the Eye Conditions That Contact Lenses Can Correct?

Contact lenses are versatile and can address similar conditions as spectacles, correcting myopia (short-sightedness), hyperopia (far-sightedness), astigmatism (distorted vision) and presbyopia (old-age vision). Contact lenses may also be used in eye diseases where an uneven cornea blurs vision, such as in patients with keratoconus.

What Are The Different Types Of Contact Lenses Available?

Soft Contact Lenses 

The majority of contact lens wearers in Singapore opt for soft lenses, which are made of plastic materials with high water content, making them soft and flexible. 

Various lens replacement schedules are available, including disposable options that are discarded and replaced, reducing the risk of allergic reactions and deposit accumulation on the lens surface.

Users should replace their contact lens according to manufacturers' recommendations. Non-disposable (conventional) soft contact lens options are also available.

Toric Contact Lenses 

Toric lenses are designed to correct astigmatism and are available in both rigid and soft materials. 

Rigid Gas Permeable Lenses 

Newer rigid plastic lenses are combined with gas-permeable materials to allow oxygen in the air to pass directly through the lens. These lenses allow more oxygen to reach the cornea compared with soft lenses.

What Are The Do-s And Don't-s Of Contact Lens Wear?

Remember to: 

  • Wash and dry your hands before handling contact lenses. 
  • Clean and disinfect contact lenses properly after each use. 
  • Clean and air-dry the contact lenses case every day. 
  • Replace lens cases regularly. 
  • Follow the lens care instructions of the manufacturer and your eye-care professional. 

Do not 
  • Reuse solutions. Discard used solutions immediately. 
  • Use homemade saline soultions.
  • Store contact lenses in non-sterile fluids such as distilled water or tap water. 
  • Wear an over-aged or damaged contact lens. 
  • Sleep with your contact lenses on.
  • Shower or swim with your contact lenses on.

Arrange for regular eye check-ups (at least once a year) with an eye-care professional.

Consult your eye-care professional or doctor before applying any eye drops, as all types of eye drops, including non-prescription ones, can interact contact lenses.

Remove the contact lens immediately if your eye turn red or feels uncomfortable while wearing them. If this persists, consult your eyecare professional or doctor immediately.

Who Should Not Wear Contact Lenses?

While most individuals requiring vision correction can wear contact lenses, there are situations where it is not recommended. These include dry eyes, frequent eye infections, severe allergies, working in a dirty and dusty environment and an inability to handle and care for lenses appropriately.

Problems Arising from Wearing Contact Lenses 

Wearing contact lenses can cause a variety of problems, ranging from mild to sight-threatening complications. These include: 

  • Dry Eyes 
  • Allergic eye disease 
  • Distortion of the cornea 
  • Changes to corneal structure due to a lack of oxygen 
  • Scratches (abrasions) on the cornea 
  • Corneal infections 
Stop wearing your contact lenses immediately if you experience discomfort. Consult an eye specialist promptly if you experience eye redness, a decline in vision or pain in the eyes.
Dry Eyes

What Are Dry Eyes?

Dry eyes, or keratoconjunctivitis sicca, is very common condition in Singapore, affecting both the elderly and young adults.

How Will I Feel if I have Dry Eyes?

You may have one or a few of the following symptoms:
  • Itch
  • Burning sensation
  • Redness of the eyes
  • Foreign body sensation (eg. feeling like there is sand in the eyes) 

What Are The Causes of Dry Eyes?

This may be due a combination of factors which includes either a decrease in tear production, increased tear evaporation, or both.

What Makes My Dry Eyes Worse?

Factors that may exacerbate dry eye symptoms include:

  • Contact lens wear;
  • Working in a dry or windy environment;
  • Prolonged staring at computer, tablet or phone screens, or reading books; and
  • Certain medications that reduce tear production, such as antihistamines for a runny nose

How Can it Be Treated?

Treatment modalities for dry eyes vary based on individual assessments. Consider the following approaches:

Avoidance: Steer clear of situations or environments that worsen dry eyes.

Artificial Tears: In mild cases, using artificial tears up to four times a day may suffice. Severe cases may benefit from preservative-free artificial tears, which can be used as frequently as needed. Eye ointments, while providing longer lubrication, may cause slight blurred vision and are recommended for night-time use.

Biological Tear Substitutes: Severe cases may involve the use of biological tear substitutes like autologous serum. This involves using the fluid component of blood after clotting, and while effective, it comes with the invasiveness of serum collection and infection risks.

Anti-inflammatory Eye Drops: In cases with signs of inflammation, especially severe dry eyes, eye drops containing steroids or cyclosporin may be recommended. Due to potential side effects, the use of such medications should be closely supervised by a medical professional.

Tear Conservation Approaches: Tears drain through eyelid openings (punctum) into the nose. Temporary or permanent occlusion techniques can block these openings, reducing tear drainage and subsequently alleviating dryness.

Moisture Chamber Eye-Glasses and Humidifying Devices: These devices have been suggested as effective in maintaining moisture.

Concurrent Eyelid Disease: Dry eye symptoms may be influenced by eyelid disease. Managing these issues, as detailed in the Blepharitis/Meibomitis section, can contribute to alleviating dry eye symptoms.

Watch this video to learn about the symptoms and causes of dry eye disease:

Watch this video to learn about the diagnosis of dry eye disease:


What is a Pterygium?

A pterygium is an abnormal tissue growth on the surface of the eye. This can lead to vision problems if it distorts the cornea. It may also cause irritation and redness of the eye.

Are There Eye Drops to Manage This Condition?

When eye irritation occurs, artificial tears may be prescribed for comfort. In cases of inflammation (red and painful), steroid eye drops may be prescribed to reduce the inflammation. However, these eye drops only reduce discomfort associated with the presence of a pterygium.

How Is It Removed?

Over time, the pterygium will grow towards the centre of the cornea and potentially affecting vision. Definitive treatment in this instance is to remove the pterygium surgically. The procedure typically involves covering the exposed area with normal conjunctival tissue to reduce recurrence rates to around 10%. Various attachment methods, such as absorbable sutures and medical-grade glue, may be employed during surgery.

What is the Post-Surgery Experience Like?

The procedure is often performed under local anaesthesia. You will be prescribed eye drops following surgery. Expect a foreign body sensation and some discomfort for several weeks following the procedure.

What Can Go Wrong?

The surgery is considered safe, with the likelihood of sight-threatening problems occurring in less than1 in 5,000 cases.
Cornea Transplant

What Is a Cornea Transplant?

A cornea transplant is a surgical procedure to replace the transparent tissue on the front surface of the eye. This intervention becomes necessary when the cornea becomes cloudy, causing a reduction in vision. During the operation, the central portion of the affected tissue is removed and replaced with donor corneal tissue to enhance vision.

What Are the Risks?

While a cornea transplant is generally a safe procedure typically performed under general anaesthesia, there are inherent risks:

Rejection Risk: The primary risk is rejection, an immune response by the body against the transplanted tissue. The cornea is considered an organ, and while the rate of rejection is generally low, any episode can often be reversed with early use of prescribed eye drops or systemic medications to suppress the immune response. In cases of persistent rejection, where the cornea becomes cloudy, a repeat cornea transplant may be considered.

Serious Complications: Instances of serious complications, such as eye infection or bleeding during surgery, are extremely rare, occurring in about 1 in 5,000 operations. However, these rare complications can potentially lead to total loss of eyesight or even loss of the eye itself.

Donor Tissue Safety: Cornea transplant uses human tissue obtained from donors who undergo rigorous testing for blood-borne infections. Tissues testing positive for infections will not be used, ensuring the safety of the donor tissue.

What Do I Need to Do after Surgery?

An eye patch is typically worn for a day post-surgery, and a plastic shield must be worn at bedtime for one month. This shield aids in protecting the eye during the crucial initial healing phase. Eye drops are used for at least six months following surgery. In some cases, it may indefinite use is necessary. 

You can generally resume normal activities such as walking, showering and bathing the day after surgery. However, vigorous activities should be avoided for at least a month after surgery.

When Will I See Well Again?

There may be sutures in place to secure the new cornea after surgery. These will be gradually removed during follow-up. The best achievable vision is usually realised the complete removal of sutures. However, some sutures may stay in place indefinitely. To achieve the clearest and most refined vision, wearing spectacles might be recommended.
Paediatric (Children) Cornea Transplant

What Is the Cornea and What Is Its Function?

The cornea is the clear outermost layer of the eye. It plays an important role in providing clear vision by refracting incoming light onto the lens, which is then refocused onto the retina, an area where conversion of light into vision occurs. 


What Is the Cornea and What Is Its Function

A diseased cornea prevents light rays from reaching the retina, resulting in  poor vision. In some cases, a corneal transplant may be necessary to restore visual function.

What Is a Corneal Transplant?

Corneal transplant surgery involves the removal of the damaged cornea and replacing it with a healthy donor cornea. 

What Are the Different Types of Corneal Transplant?

There are two main types of corneal transplants: 

  • Full thickness corneal transplant (Penetrating Keratoplasty), which involves the complete replacement of the cornea.

  • Partial thickness corneal transplant, which includes either transplanting the outer layer of the cornea (Anterior Lamellar Keratoplasty) or the innermost layer (Endothelial Keratoplasty).

What Is a Corneal Transplant


The corneal specialist will advise on the appropriate surgery according the individual's specific needs.  

Why the National University Hospital? 

The NUH paediatric Corneal Transplant Team is made up of corneal specialists, paediatric ophthalmologists, glaucomatologists, optometrists, the paediatric transplant team and anaesthetists. This multi-disciplinary approach to care is especially important in paediatric cases with a high risk of rejection and graft failure. We offer comprehensive pre- and post-transplant evaluation, including individualised peri-operative immunosuppression and post-operative visual rehabilitation to prevent graft rejection, thereby optimising visual outcome. 

Who Will Need a Corneal Transplant?

Corneal transplants can be used to treat both congenital and acquired corneal diseases. Common congenital causes of corneal opacities/oedema include congenital hereditary endothelial dystrophy, posterior polymorphous corneal dystrophy, congenital hereditary stromal dystrophy, Peters' anomaly, congenital glaucoma, sclero-cornea, epibulbardermoid and metabolic disorders. Common acquired causes of corneal opacities/oedema include trauma-related corneal injuries, corneal scars, keratoconus, keratoglobus, Stevens-Johnson syndrome and toxic epidermal necrolysis.

How Is a Corneal Transplant Performed? 

Performed under general anesthesia, the corneal transplant involves removing the diseased cornea and replacing it with a clear donor cornea button, securely fastened with sutures.

In Endothelial Keratoplasty, a gas bubble is injected into the eye to tamponade the transplanted graft in place. Maintaining a post-operative supine position for 1-2 days is crucial in these cases. 

How is a cornea transplant performed

The surgery is usually performed as a day surgery procedure. Admission and assessment by a pre-operative anaesthetist may be required for high-risk patients 

What Is the Success Rate of Corneal Transplant?

The success rate for corneal transplants exceeds 90%. Although patients may experience astigmatism, leading to some degree of visual blurring, the majority witness significant improvement in vision over the initial months post-transplant.

What Are the Risks of a Corneal Transplant?

Risks of corneal transplants include, but are not limited to ocular bleeding, infection such as keratitis or endophthalmitis, glaucoma, graft rejection, cataract formation and retinal detachment. The operative risks include those of general anaesthesia. 

What Is Corneal Graft Rejection and How Is It Treated?

Graft rejection is a recognized complication wherein the immune system perceives the donor cornea as foreign and attacks it. While rejection can occur at any time post-transplant, it is most common within the first two years. Approximately 20% of corneal transplants face rejection, typically treatable with immunosuppressive therapy. Repeat transplants carry a higher risk, necessitating more intensive immunosuppressive measures. 

What Is the Care Required After Corneal Transplant?

Frequent administration of topical steroid eyedrops for at least fiveyears (depending on the type of transplant) after corneal transplant is essential to reduce the risk of graft rejection. Administering eyedrops to infants or young children may pose challenges, requiring patience and diligence from caregivers.

For infants and young children unable to cooperate with post-operative examination, sedation or anaesthesia may be required after a corneal transplant. Suture removal is usually performed a few months to years later, depending on the rate of recovery, presence of suture-related complications, and the degree of induced-astigmatism.

What Is the Long-Term Care After a Corneal Transplant?

After a corneal transplant, the focus shifts to long-term care, particularly in the case of infants and children undergoing keratoplasty. Successful visual rehabilitation requires addressing factors like amblyopia ('lazy eye') resulting from pre-surgery visual deprivation, graft astigmatism, and anisometropia. Collaborative care with a Paediatric Ophthalmologist is crucial for optimising post-operative visual recovery.

What Can You Do as the Caregiver at Home?

Children tend to rub their eyes during the healing period, risking broken sutures and corneal wound dehiscence. These actions may increase the risk of rejection and infection. Caregivers should observe for increased  eye redness, corneal haziness or opacities. Any reported drop in vision or pain requires prompt attention, necessitating an early appointment to address concerns promptly.

Where Can I Find out More Information? 

Book an appointment with the NUH Eye Surgery Centre for a comprehensive eye check-up and recommendations for your individualised treatment plan.
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