Cornea and External Eye Diseases

• 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)
  

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. 

Lubricants

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. 

Antibiotics

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.

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.

• 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. 
  

• 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.

• 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 

• Itch
  
• Burning sensation
  
• Redness of the eyes
  
• Foreign body sensation (eg. feeling like there is sand in the eyes) 
  

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

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.

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.

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.

• 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).

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. 

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?

What Is Corneal Graft Rejection and How Is It Treated?

What Is the Care Required After Corneal Transplant?

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

What Can You Do as the Caregiver at Home?

Where Can I Find out More Information?