PTERYGIUM (EXTERNAL MRENA)
What is pterygium?
One of the common conditions that can threaten eyesight is pterygium. It is a vascularised duplication of the conjunctiva, usually in the inner (medial) part of the eye, which crosses the cornea and with its growth can obscure the visual axis.If left untreated, it can deform the cornea with its growth and cause irregular astigmatism and impair visual acuity.If it grows completely over the cornea, the visual impairment is more severe and sometimes permanent.
Pterygium treatment
Adequate UV protection (100% UV sunglasses) must be worn to prevent the development of the pterygium. If pterygium starts to form, artificial tears and anti-inflammatory eye drops are prescribed, as recommended by a specialist doctor. It is not necessary to procrastinate with surgery because the procedure is easier and more effective if done at an early stage.
Risk factors are:
Age Group
It occurs most commonly in the middle or older age and the main risk factor is exposure to UV radiation, so pterygium is most common in people who spend time outside, especially near water due to the reflection of the sun from its surface. Also, people who spend their working hours in the sun (e.g. construction workers, farmers) are at risk if they do not use adequate UV protection.
Pterygium Causes
The most common cause is overexposure to UV radiation and adverse conditions such as wind and smoke that lead to a change in the connective tissue of the matrix (matrix metalloproteinase) with insufficient control of the corneal limbal stem cells, which leads to uncontrolled tissue overgrowth. It may have a tendency to grow again after the surgery.
Pterygium Symptoms
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Vascular formation in the nasal corner of the eye that looks like a wing with a base to the nose and a tip on the cornea that often causes irritation and a cosmetic problem
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Pterygium with its growth can pull the cornea and cause irregular astigmatism, i.e. the eyesight may worse
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Scratching, tearing, foreign body sensation in the eye If it grows all the way to the centre of the cornea, it can cause permanent damage to the eyesight
Incidence M / F
Pterygium occurs more frequently in men than in women. Studies showing rates as high as 50% increased prevalence in men.
SURGICAL METHODS
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Conventional surgery
With this method, the pterygium is surgically removed and the defect at the junction is sutured with a microsurgical suture, which does not need to be removed because it dissolves after 10 days. If necessary, conjunctival flap rotation is performed. Special drugs (antimetabolites – Mitomycin C, 5 fluorouracil) may be applied locally during the procedure to reduce the recurrence rate to a minimum.
Limb stem cell auto transplant surgery (LCAT)
This operative method is especially effective in recurrent pterygia, i.e. those that have regrown after standard surgery or as the primary method for maximum possible stability after surgery. With surgical removal of the pterygium, healthy tissue of the corneal limbal cells is taken and transplanted to the site of the removed pterygium to create a natural barrier to a cell regrowth. This world-renowned and effective method requires extensive surgical experience and expertise and has been successfully performed at the Knezovic Eye Institute.
Amniotic membrane transplantation
Amniotic membrane transplantation is an effective alternative treatment for severe anterior eye segment conditions such as persistent corneal ulcers, bullous keratopathy or more extensive pterygium removal.
The amniotic membrane is a tissue that is obtained from the deepest layer of the human placenta which is rich in substances that facilitate tissue healing, and is used to replace and treat mucous surfaces, for example, to reconstruct the ocular surface.
It has been used as a surgical material since the 1940s and has been shown to have a strong anti-adhesive effect. After an amniotic membrane has been transplanted, it stimulates epithelialisation and has an anti-inflammatory effect which rejuvenates the surface layers. The amniotic membrane transplant can be fixed using sutures or adhesive “glue” substance. Applying special tissue adhesive and mitomycin-C have given excellent cosmetic results on eye surface.
Pre-operative pterygium examination
Prior to the surgery of the pterygium, a detailed examination is performed. It includes the refractive status of the eye, eye pressure measurement and slit lamp examination of the eye. Then, it is described to the patient what the procedure will look like, the patient is asked to sign an informed consent and receives necessary premedication. When entering into the operating room, the patient receives a sterile cap and sockets.