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Retinal Detachment

Introduction

 

Retinal detachment (RD) - Separation of the sensory retina from the retinal pigment epithelium (RPE) by subretinal fluid (SRF).

 

It is one of the most time-critical eye emergencies along with central retinal artery occlusion and chemical burns to the eye. 

 

Epidemiology

 

  • Incidence: 10-15/100 000
  • More common in 40-70 years age group. Traumatic RD can occur in younger patients.
  • More common in males, in the right eye and with increasing affluence.

 

Classification

 

RD can be broadly classified into 3 categories: 

 

1) Rhegmatogenous RD (most common) - due to a retinal break, hole or tear.

  • Retinal breaks are full thickness defects of the sensory retina.
  • Tears are caused by dynamic vitreoretinal traction.
  • Holes are caused by chronic atrophy of the sensory retina.

 

2) Tractional RD - due to pre-retinal membrane formation and scarring that pulls the retina away from its attachment.

Important causes:

  • Proliferative diabetic retinopathy
  • Retinopathy of prematurity
  • Sickle cell retinopathy
  • Trauma

 

3) Exudative/Serous RD - due to abnormalities in the transport of water across the RPE or in its blood supply.

 Important causes:

  • Tumours
  • Posterior scleritis
  • Subretinal neovascularisation
  • Severe hypertension

 

 



Risk Factors



Symptoms and Signs

 

Floaters (moving vitreous opacities casting a shadow on the retina)

 

Flashes (photopsia - probably caused by traction on the retina at sites of vitreoretinal adhesion)

 

Field loss (perceived as a dark curtain)

 

Falling acuity (loss of central vision due to involvement of the fovea)

 

 

Marcus Gunn Pupil (Relative afferent pupillary defect) - detected using the swinging light test. As the flashlight is swung from the unaffected eye to the affected eye, the pupils constrict less (therefore appearing to dilate). 

 

Intraocular pressure in affected eye normally lower (5 mmHg) than normal eye

 

Mild anterior uveitis is very common 

 

Red discontinuities on the retinal surface

 

Signs

Marcus Gunn PupilRed discontinuities on the retina in RD (Wills Eye Hospital Atlas of Clinical Ophthalmology)

Differential Diagnosis

  1. Degenerative retinoschisis - a benign condition where the retina is split into layers.
  2. Choroidal detachment - detachment of the vascular layer of the eye.
  3. Uveal effusion syndrome - rare, idiopathic condition characterised by choroidal detachment associated with RD. Normally self-limiting. 

 

Investigations

Picture from http://www.eyeweb.org/atlas/rd.htm

Gold standard - Binocular indirect ophthalmoscopy with scleral indentation.

 

Ultrasound could also be used. RD is seen as a thick, undulating, hyperechoic membrane that appears to have been lifted off the posterior wall of the eye.

 

Optical Coherence Tomography (OCT) could also be used prior to surgery in order to document the amount of fluid below the retina. OCT would show a break or tear in the retina and any space below the retina, where it has separated from the underlying membrane.

 

Management

 

Treatment is via Laser, Cryotherapy or Surgery. Exudative RD is treated by resolving the underlying cause.

  1. If macula still attached - MEDICAL EMERGENCY: operate within 24 hours
  2. If macula already detached - surgery within a week to prevent complications

The principle of surgery is to close all the breaks to prevent new breaks and complications occurring. 

 

Retinal detachment surgery options:

  • Pneumatic retinopexy - injection of gas bubble into vitreous to close the tear.
  • Scleral buckle - band placed around the equator of the eye to prevent any forces pulling the retina out of place.
  • Vitrectomy - removal of vitreous gel pulling on the retina.

 

Post surgery - Corticosteroid drops (to reduce inflammation) and prophylactic antibiotic drops are given. The patient is advised to keep their head in a certain position or not to travel on an aeroplane if a gas was injected into the eye.

 

Complications

  1. Permanent loss of vision - if the RD remains untreated or there is involvement of the macula.
  2. Epiretinal membrane - due to chronic low grade inflammation, a fibrous tissue can grow over the retina causing retinal folds and distortion of vision.
  3. Vitreous haemorrhage - can lead to loss of vision due to blood in the vitreous.
  4. Secondary glaucoma - longstanding RD can result in an increase in intra-ocular pressure leading to optic atrophy.

 

    Prognosis

    Prognosis is inversely related to the degree of macular involvement and the length of time the retina has been off. 

     

    References

    www.medicinenet.com/retinal_detachment

    www.emedicine.medscape.com/article/798501

    www.patient.co.uk/doctor/retinal_detachment

    http://www.eyeweb.org/atlas/rd.htm

    http://www.acep.org/content.aspx?id=45426

    Clinical Ophthalmology A Systematic Approach, Fifth Edition, Jack Kanski

    Jalali, Retinal Detachment, Journal of Community Eye Health, 2003

    Wills Eye Hospital Atlas of Clinical Ophthalmology

     

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