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Retinal tear and detachment

 

Dr Andrew Chang MBBS PhD FRANZCO FRACS

Vitreoretinal surgeon

Sydney Retina Clinic and Day Surgery

Level 13 187 Macquarie Street

http://www.sydneyretina.com.au

What are the different types of retinal detachment?

 

Retinal detachment is a separation of the neurosensory retina from the underlying retinal pigment epithelium.

There are several types of retinal detachment

1. Rhegmatogenous retinal detachment. This results from liquefaction of the vitreous gel and a posterior vitreous detachment. This is an age-related collapse of the collagen framework of the vitreous gel.

:PVD.jpg:US PVD.jpg

 

The separation of the vitreous produces tears in the retina. The vitreous fluid passes through the tear and this produces a retinal detachment which progresses until the retina it totally detached.

:tear.jpg:large PD.jpg

2. Tractional retinal detachment. Fibrosis of the vitreous face results in a traction band to the retina producing a retinal detachment. This occurs typically in proliferative diabetic retinopathy (as illustrated below).

:TRD.jpg:TRD dissection.jpg

:Diabetic TRD.jpg

 

3. Exudative retinal detachment. This is caused by subretinal fluid leaking under the retina. Inflammatory conditions such as posterior scleritis, Harada’s choroiditis, tumours and choroidal new vessels can result in retinal detachment.

:Exudative RD.jpg

Posterior scleritis and exudative retinal detachment.

:melanoma.jpg

Choroidal melanoma and exudative retinal detachment.

 

What are the important symptoms?

 

Flashing lights (photopsia) indicates traction to the light sensitive retina. The typical symptoms are brief lightening flashes usually seen in the dark and with rapid head or eye movement. Photopsia may occur in other conditions such as migraine, occipital lobe tumours and arteriovenous malformations.

Floaters results from the collapse of the vitreous gel. Patients may find the floaters more noticeable on a light background. Larger floaters may indicate vitreous haemorrhage.

These symptoms will be present with a posterior vitreous detachment. The symptoms may be very transient or last several months. The duration correlates with the degree of vitreous traction to the peripheral retina. B scan ultrasound may be useful in demonstrating the degree of peripheral vitreoretinal traction.

A peripheral enlarging scotoma is the classic symptom of a retinal detachment. Superior detachments associated with an inferior visual field defect usually progress more rapidly.

How often should the patient be reviewed?

 

Most patients with a vitreous detachment remain uncomplicated and is not vision threatening. Approximately 10% of vitreous detachments may be associated with a vitreous haemorrhage, retinal tear or retinal detachment. These patients should be reviewed in 1-2 weeks. It is important to educate the patient on the symptoms of retinal detachment and to ensure that the patient seeks attention urgently if the symptoms change. This should be documented in your notes.

Which patients should be referred for further assessment?

1. Patients with persisting symptoms.

2. Blood or pigment cells in the vitreous may suggest a retinal tear or detachment.

3. Patients at high risk of retinal detachment: past or family history of retinal detachment, high myopia, traumatic cases.

4. Extensive lattice degeneration.

5. Situations in which follow-up may be unreliable.

How should the patient examined and investigated?

 

Slit lamp biomicroscopy using wide-angle lens or 3 mirror lens will reveal even very small retinal tears or detachment.

Indirect ophthalmoscopy with scleral indentation is useful in demonstrating peripheral holes and tears or areas with abnormal vitreous traction.

B scan ultrasound will demonstrate the position and mobility’s of the vitreous.

In some patients the visual field loss resulting from retinal detachment will be diagnosed on visual field testing.

How are tears treated?

:laser.jpgRetinal tears are usually treated using either slit lamp or indirect laser photocoagulation. This is performed using topical anaesthesia in the office.

However if the tears are obscured by vitreous haemorrhage, are associated with subretinal fluid or are located too anteriorly, treatment with cryotherapy may be necessary. This treatment is performed under local anaesthetic in an operating room.

 

What is the preferred method of treating retinal detachment?

 

There are a number of ways to repair a retinal detachment. Additionally there are new advances in the surgical repair.

1. Scleral buckle. This involves placing a silicone strap and band around the circumference of the globe under the extraocular muscles. The aim is to indent the globe towards the retina. This surgery is effective and is considered the gold standard of retinal detachment repair.

:buckle.jpg 

:buckle surgery.jpg

 

2. Pneumatic retinopexy. A gas bubble is injected into the vitreous cavity which closes the tear in the retina. Subsequently laser or cryotherapy is performed to treat the edges of the tear.

 

:pneumatic 1.jpg :pneumatic final.jpg

 

 

3. Vitrectomy. This is microsurgical keyhole approach to the interior of the vitreous cavity. The vitreous is removed, the detached retina is repositioned using special gases or fluids.

:vitrectomy.jpg:surgeon view.jpg

 

Changing approaches to retinal detachment repair.

 

In recent years, there has been a shift towards vitrectomy repair of retinal detachment. This is due to technological improvements in the instrumentation and viewing systems.

Small gauge sutureless vitrectomy approaches are well tolerated by the patient and effective.

 

 

 

 

 

 

However, vitrectomy does have a different set of side-effects and potential complications. Cataract in phakic eyes usually accelerates following surgery. This is now thought to be due to increased oxygenation of the vitreous cavity which results in cataract formation.

Vitrectomy surgery is recommended in the following situations:

1. Large and posterior retinal tears

2. Vitreous haemorrhage

3. Giant retinal tears

4. Advanced retinal scarring (PVR)

:PVR.jpg:GRT.jpg

 

What are the differences between scleral buckle surgery and vitrectomy?

Scleral buckle

Vitrectomy

More conjunctival scarring and external globe manipulation

Minimal conjunctival scarring. Suitable for patients with glaucoma who may require subsequent  trabeculectomy filtration surgery

Scleral buckle surgery may be more  difficult in very high myopes with thin sclera.

Vitrectomy avoids these side-effects. Longer instruments may be required in large eyes.

Cataract is less common.

Risk of cataract (depending on the patients age).

Extraocular muscle imbalance and induced myopia due to globe distortion.

No disturbance with the muscles and the globe is not distorted.

Small gas bubble

Larger gas bubble

Peribulbar anaesthesia

Peribulbar anaesthesia

Less demand on technology

High demand on technology and instrumentation

What is the cause of failure in retinal detachment?

The most common cause of re-detachment of the retina is development of scar tissue on the retina, termed Proliferative Vitreoretinopathy (PVR). This scarring creates shortening of the retina and detaches the retina again. The risk of PVR increases with the size and number of the tears and extent of the retinal detachment, the duration of symptoms before surgical repair, age, presence of vitreous blood.

The following illustration shows the severe scarring and shortening of the retina. This would require further complex surgery and pressure with silicone oil. Untreated this case would result in shrinkage and possible loss of the globe.

 

:PVR tear.pdf

 

 

How can we improve the success of surgery?

Retinal detachment is an urgent and blinding condition. Early diagnosis and referral for surgical repair is essential. As retinal re-detachment can occur at any time, patients should be instructed in what to look out for so they can attend for reassessment.

Once the macula is involved the recovery of fine central vision is limited. However with timely surgery with modern techniques allow the repair of even very complex retinal detachments with recovery of vision and preservation of the globe.

 

 

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