INSTRUCTION

Examine this patient's eye.

SALIENT FEATURES

History

· Patient complains of a dark curtain progressing across the visual field.

· Floaters, flashes.

· History of diabetes, hypertension.

· History of kidney disease (diabetic renal-retinal syndrome).

Examination

· The retina has lost its pink colour and appears grey and opaque.

· When the collection of subretinal fluid is large, the retina shows ballooning

detachment with numerous folds (Figs 87 and 88).

· Examine visual acuity and visual fields.

Proceed as follows:

Tell the examiner lhal yon wonld like to :

· Check urine for sugar.

· Check the blood pressure.

· Comment on any walking aid for the registered blind.

DIAGNOSIS

This patient has neovascularization and retinal detachment (lesion) due to under-lying

diabetes mellitus (aetiology). She has a walking aid for the registered blind (functional

status).

ADVANCED-LEVEL QUESTIONS

What is the pathology of retinal detachment?

It is a separation within the retina between the photoreceptors and the retinal pig-ment

epithelium, characterized by collection of fluid or blood in this potential space.

What are the types of retinal detachment?

Rhegmatogenous retinal detachment

This is defined as the presence of a hole or break in the retina that allows fluid from the

vitreous capacity to enter the subretinal space. It usually occurs spontaneously in those

who have a predisposition to it following trauma to the eye or after intra-ocular surgery.

Most of these patients develop symptoms. A break in the peripheral retina is associated

with a sudden burst of flashing lights or sparks that may be followed by small floaters or

spots in the field of vision. When the retina detaches, the patient perceives a dark

curtain progressing across the visual field, and when the fovea detaches central vision

is abruptly diminished.

It is treated surgically with a scleral buckling procedure (where all retinal breaks are

localized and adhesions between the choroid and retina are performed around the

break with diathermy or a cryoprobe). After draining the subretinal fluid, the detached

portion of the retina is indented towards the vitreous cavity by a scleral implant or

explant. This results in pushing of the retina towards the vitreous, causing closure of the

retinal break (by the buckled sclera and choroid) and release of traction of vitreous.

Traction retinal detachment

The intact retina is forcibly elevated by contracting membranes on the surface of the

retina or by vitreous traction on areas of retinal neovascularization. Causes include

diabetes, intraocular foreign body, perforating eye injuries and loss of vitreous fol-lowing

cataract surgery. These retinal detachments are difficult to treat; pars plana vitrectomy

is the only way to treat these lesions.

Secondary retinal detachments

These occur secondary to systemic disorders including hypertension, toxaemia of

pregnancy, chronic glomerulonephritis, retinal venous occlusive disease and retinal

vasculitis. Treatment is directed towards the underlying cause as these detachments

are not amenable to scleral buckling surgery.