A-Z of posterior eye conditions

Hypertensive DESCRIPTION retinal vein occlusion; Central retinal Hypertensive retinopathy develops as artery occlusion; ; a result of two broad and interplaying Pregnancy. mechanisms: ● Arteriolosclerosis. This occurs over MANAGEMENT many years, and is thought to result mainly from leakage of plasma across Urgent the vascular endothelium. The arteri- Severe, acute with disc olar walls are homogeneously thick- swelling (malignant hypertension) is a ened with hyaline material, and are less medical emergency with a poor progno- able to respond to fluctuations in blood sis. Immediate hospital admission is pressure. required. ● Arteriolar leakage and occlusion. The physiological reflex response to Blood tests an acute elevation in is Initial investigations include full blood vasoconstriction. However, with severe ● With progression of arteriolosclerosis Multiple examination, urea and electrolytes, or sustained hypertension, blood compo- and disturbance of homeostatic mecha- cotton-wool urinalysis, fasting blood sugar and nents leak into the vessel wall. This results nisms, arterioles develop irregular points spots, lipid lipid profiles, and electrocardiography. in vascular damage and disruption of of focal constriction. macular star, Investigations may be performed for the blood-retinal barrier. Histologically, ● Advanced arteriolosclerosis produces blot and causes of secondary hypertension, or there is fibrinoid necrosis with inflam- copper wiring (the increasingly opaque flame-shaped systemic complications of hyperten- matory cell infiltrates. arteriolar wall reflecting only a small haemorrhages sion. Dietary and lifestyle modifica- Sometimes hypertensive retinopathy portion of the red colour of intravascular tions will minimise cardiovascular risk. has significant visual consequences. blood) and silver wiring (intravascular Antihypertensive medications confer When vision is affected, it mostly results blood completely obscured). prognostic benefits in well-defined from focal ischaemia resulting from Signs associated with arteriolar patient groups. Regular medical and vascular occlusion. Loss of central vision leakage include retinal oedema, flame- ocular reviews are essential. can result from vascular leakage at the shaped haemorrhages and hard exudates macula. Acute, severe hypertension, as (well-defined, yellow-white lipid depos- Additional investigations in the setting of malignant hypertension its). Cotton-wool spots suggest focal Fluorescein angiography may show and pre-eclampsia, can result in occlusion retinal ischaemia caused by vascular microaneurysms, increased vascular and necrosis of the choroidal arteries, occlusion. The presence of a macular permeability and obstruction of first- leading to exudative retinal detachment. star with swelling suggests order arterioles. Pre-eclampsia is also associated with severe hypertension requiring urgent serous retinal detachment, with focal treatment. Arterial macroaneurysms Laser surgery necrosis of the retinal pigment epithe- may occur, and result from linear tears Treatment of macroaneurysms is not lium and outer . The detachment, in the vessel wall. Hypertensive patients always indicated, since thrombosis and and accompanying loss of vision, usually are at increased risk of developing retinal sclerosis often seal the vessel wall defect resolves after delivery and antihyperten- detachment, nonarteritic ischaemic optic spontaneously. Aneurysms with exuda- sive therapy. neuropathy and retinal vein or artery tion at the macula or bleeding into the occlusions. subfoveal area are treated with argon SYMPTOMS laser photocoagulation. Laser surgery is Systemic hypertension is usually asymp- prevalence also used to treat retinal detachments in tomatic. In severe, uncontrolled or acute Arteriosclerosis is common in elderly certain settings. hypertension, symptoms may include patients, and is accelerated with hyper- , altered or , tension. Most patients with chronic, The full series of these articles will be available in the altered conscious state, palpitations or moderate hypertension only develop book Posterior and A-Z by Bruce chest pain. early ocular changes. AS, O’Day J, McKay D and Swann P. £39.99. For further information click on the Bookstore at opticianonline.net SIGNS SIGNIFICANCE Retinal hypertensive changes develop Although hypertensive retinopathy is ● Adrian Bruce is a Chief Optometrist at the Victorian according to the duration and severity usually asymptomatic, there is potential College of and a Senior Fellow, Department of hypertension. Many classification for disabling loss of vision, which may of Optometry and Vision Sciences, The University of systems have been devised, but none is be prevented by timely detection and Melbourne. universally accepted. A possible grading treatment. ● Justin O’Day is an Associate Professor in the is: Department of , The University of ● The first sign of arteriolosclerosis is DIFFERENTIAL DIAGNOSIS Melbourne and Head Of Neuro-Ophthalmology Clinic, broadening of the arteriolar light reflex. ; Radiation retin- Royal Victorian Eye and Ear Hospital. At arteriovenous (AV) crossings, the opathy; Central retinal vein occlusion. ● Daniel McKay is a Medical Officer at the Royal thinner-walled veins are compressed, Victorian Eye & Ear Hospital. resulting in venous deflection or taper- SEE ALSO ● Peter Swann is Associate Professor in the School of ing. Venous dilatation or banking may Cotton-wool spots, Nonarteritic Optometry, Queensland University of Technology. occur distal to AV crossings. ischaemic ; Branch ● opticianonline.net 27.04.07 | Optician | 55