Ocular Surface Diseases
There are many diseases affecting the surface of the eye including dry eyes, recurrent corneal erosions, and ocular surface tumours.
Dry eyes, meibomian gland disease, & blepharitis
“Dry eyes” is a very common condition due to tear film dysfunction and poor lubrication of the surface of the eye. Many degeneration processes of the eyelids and ocular surface can affect the function of tears as one ages. The most common cause is meibomian gland disease (MGD) or blepharitis, which affects the oil glands in the eyelids that secrete the oily part of the tear film (there is also a mucin and aqueous layer). When there is not enough oil, the tear film becomes unstable and evaporates too quickly, causing a dry ocular surface.
Symptoms include pain, grittiness, irritation, tiredness, redness and sometimes paradoxical watering. Vision may also be affected with blurriness or fluctuation of vision. Symptoms can be exacerbated by environmental conditions such as wind, air-conditioning, or heating. Activities that require visual concentration (eg computer use, reading, watching TV, driving) that result in less blinking can also worsen the condition.
How is dry eye treated?
Unfortunately, dry eye cannot be cured but there are treatments to relieve symptoms and improve your quality of life. These include:
Lubricating drops (preservative-free are best)
Warm compresses and massage around the eyelids
Eyelid hygiene with cleaners to reduce inflammation and bacteria around the eyelids
High dose omega-3 supplements
Anti-inflammatory eye drops such as steroid drops may be beneficial
Doxycycline tablets may be used to reduce inflammation in blepharitis
Blocking the draining ducts with punctal plugs to retain more tears on the surface
Be aware of environmental factors such as air-conditioning; wear sunglasses in windy conditions; and take regular breaks from activities that require visual concentration
Recurrent corneal erosion syndrome
The cornea (the clear window in the front of the eye) comprises several layers, with the outermost surface being called the epithelium. The epithelium should be firmly adherent to the underlying layers. In some circumstances, the epithelium can become unstable and be dislodged by minor trauma or friction from the eyelids.
Symptoms include severe pain, watering, and sensitivity to light, typically occurring in the middle of the night or upon waking.
The most common causes are:
Trauma – superifical corneal abrasions caused by trauma such as fingernails, plants, or paper
Epithelial basement membrane dystrophy (EBMD) – this is a genetically determined condition whereby the adhesion of the epithelium is affected by abnormal material deposited beneath it. If this occurs in the central part of the cornea, then vision may be affected as well.
Other corneal dystrophies
Blepharitis – inflammation of the eyelids may release inflammatory chemicals into the tear film that interfere with corneal adhesion
How is recurrent corneal erosion syndrome treated?
Conservative measures that may improve or alleviate the symptoms completely include:
Lubrication: Thicker gels or ointment at night time should be used to reduce the friction between the eyelid and cornea. Thinner preservative-free lubricants can be used during the day
Treatment of blepharitis: This may include eyelid hygiene and warm compresses, steroid drops, doxycycline, and high dose omega 3 supplements
What is laser phototherapeutic keratectomy (PTK)?
If erosion symptoms still persist despite conservative measures, then laser PTK may be considered. Dr Ang will discuss with you if this is a suitable treatment for you. It involves removing the abnormal epithelial layer with alcohol and debridement, “tickling” the underlying layer with the excimer laser to promote adhesion, and then placing a bandage contact lens for a week to assist healing of the new epithelial layer of cells.
Ocular surface tumours
Like our skin, the surface of the eye can also be susceptible to damage by UV radiation. This may cause tumours on the ocular surface, or the medical term is “ocular surface squamous neoplasia” (OSSN). Fortunately, most are usually detected in the early stages when they are still superficial.
OSSN is usually diagnosed by examination of the eye, and sometimes a biopsy called impression cytology is required. This is done during the appointment under local anaesthetic drops and is quick and painless.
Treatment involves either chemotherapy eye drops or surgical excision. Dr Ang will discuss with you which treatment option is advised for you.
