CPD Article Common eye disorders in the elderly – a short review Visser L, FCOphth(SA), MMed(Ophth) Acting Head of Department of Ophthalmology, Nelson R Mandela School of Medicine, University of KwaZulu-Natal Correspondence to: Dr Linda Visser, e-mail [email protected] Abstract As the eye ages, certain changes occur that may affect vision. Presbyopia is corrected by the use of reading glasses. Cataracts are common and vision can be restored following a reasonably simple operation. Visual loss due to glaucoma can be minimised by early detection and treatment, but once vision has been lost it cannot be recovered. Much research is being done on the treatment of age-related macular degeneration, but this currently remains the main cause of irreversible loss of vision in the elderly. Results of macular hole surgery are improving due to improved surgical techniques and better diagnostic equipment (Optical Coherence Tomography). Underlying vascular disease (systemic hypertension, diabetes, atherosclerosis, vasculitis) is usually present in patients with retinal artery occlusion, retinal vein occlusion or anterior ischaemic optic neuropathy. SA Fam Pract 2006;48(7): 34-38 Introduction of treatment has been measured in is the most common and one of the Loss of vision in the elderly can have terms of less loss of vision rather than earlier age-related disorders of the a multitude of causes. Often the a gain in vision. Recent advances in eyes. Symptoms of presbyopia usu- remedy is simple, for example pre- the treatment of AMD with intraocu- ally begin between the ages of 40 scribing spectacles (as in the case lar injections are however showing and 45 years, although they may be- of presbyopia) or a reasonably small promise with many patients regain- gin earlier in hyperopes (farsighted operation (as in the case of cata- ing some of the vision initially lost. people) and later in myopes (near- ract) and all that is needed from the sighted people).1 Patients notice general practitioner, is to make the Presbyopia that they need to hold reading mate- diagnosis, reassure the patient and Presbyopia (“farsightedness of ag- rial further away to read clearly. The refer him /her to the eye care practi- ing”) is the gradual loss of accom- problem is easily remedied by the tioner for definitive management. In modative response of the eye, resul- use of reading glasses (convex or cases of profound and sudden loss ting from the loss of lens elasticity. It “plus” lenses). The rule of thumb for of vision, where vascular occlusion Figure 1: Mature cataract (retinal artery or vein occlusions and anterior ischaemic optic neuropathy) is suspected, it is however important for the general practitioner to be able to recognise the entity and institute initial emergency management prior to referral. These patients also usu- ally have some underlying vascular disease (systemic hypertension, dia- betes, atherosclerosis or vasculitis), which may need investigating. Age- related macular degeneration (AMD) remains the main cause of irrevers- ible loss of vision in the elderly, and unfortunately, though there are nu- merous treatment options available, until recently, results of most of these have been disappointing. Success 34 SA Fam Pract 2006:48(7) SA Fam Pract 2006:48(7) 35 CPD Article choosing these glasses is age less shaped peripheral lens opacities, focal distances (near and far).3 40 divided by 10. Thus, a fifty-year- often called “cortical spokes”, which Discovering co-existing pathology old patient would probably need +1 are seen as dark shadows against does not preclude the patient from dioptre reading glasses. the red reflex. The early symptoms having cataract surgery, but may are glare from intense focal light necessitate advising the patient on Cataract sources such as the headlights of a guarded visual prognosis. There is Age-related cataract is a very com- oncoming cars and, sometimes, some controversy whether cataract mon cause of visual impairment in monocular diplopia. They enlarge surgery can hasten the progression older adults. The prevalence of cata- and coalesce with time. When the of some disease processes, such as racts in people aged between 65 entire cortex becomes opaque and age-related macular degeneration, and 74 years is 50% and it increases white, the cataract is said to be ma- glaucoma and diabetic retinopathy. to 70% in those over the age of 75 ture (see Figure 1). Furthermore, the choice of IOL and years.2 There are three main types Posterior subcapsular cataracts postoperative management may dif- of age-related cataracts: nuclear, are seen more often in younger pa- fer from routine cases.4 cortical and posterior subcapsular. tients. The central posterior pole of The decision regarding whether or Components of more than one type the lens is affected and near visual not cataract surgery is warranted is usually are present. acuity is more affected than distance based not on a specific visual acuity, Nuclear cataract is caused by an visual acuity. Patients also complain but rather on whether reduced visual excessive amount of hardening and of glare and poor vision under bright function substantially interferes with yellowing of the lens nucleus and lighting conditions. A dense central a patient’s desired activities. can be seen as a central black ring opacity is seen against the red re- against the red reflex when exami- flex. Figure 3: Drusen at the posterior pole ning the eye with an ophthalmoscope The treatment of cataract entails with the pupil dilated. It causes grea- its surgical removal with the implan- ter impairment of distance rather than tation of an intraocular lens (IOL) near vision. Early in the condition, the (see Figure 2). The modern tech- hardening of the lens nucleus leads nique of small incision, sutureless to a change in the refractive index of phacoemulsification with foldable the lens, which in turn leads to a my- lens implantation is a safe proce- opic shift in refraction. This temporar- dure, performed under local or topi- ily enables the presbyopic patient to cal anaesthesia as ambulatory/day read without reading glasses and is case surgery and results in immedi- sometimes referred to as “second ate visual recovery. sight”. In advanced cases of nuclear A more recent advance in cataract cataract, the lens nucleus becomes surgery is the implantation of multifo- opaque and brown and is called a cal IOLs, which simulate accommo- brunescent nuclear cataract. dation by allowing pseudophakic pa- Cortical cataracts start as wedge- tients to visualise images at different Glaucoma From the literature from the USA, pri- Figure 2: IOL in the capsular bag following cataract surgery mary open angle glaucoma (POAG) occurs in 1.3% to 2.1% of the popu- lation over the age of 40 years and the incidence increases to nearly 15% in the population over 80 years.5 The figures for South Africa are not readily available, but it is known that POAG occurs more frequently, has an earlier onset and is associated with higher intraocular pressures in black people than in white people. [See article in this issue on glaucoma – p46] Age-related macular degeneration (AMD) AMD is the leading cause of blind- ness in patients over the age of 50 years in the Western world. At least 34 SA Fam Pract 2006:48(7) SA Fam Pract 2006:48(7) 35 CPD Article Figure 4: Choroidal neovascular mem- Figure 5a: Right and left fundi with exudative AMD brane with surrounding subretinal haem- orrhage Figure 5b: Same patient with bilateral disciform scars a year later 10% of people aged between 65 and 75 will have lost some central vision due to AMD. In those older than 75 years, 30% will be affected to some degree.6 It is more common in Cau- casians. The earliest clinical mani- festation of AMD is the appearance of small, discrete, slightly elevated, yellow-white spots at the posterior poles of both fundi, called drusen (see Figure 3). They are rarely seen before the age of 45, are not uncom- mon between the ages of 45 and 60 and are frequently seen thereafter. acuity < 6/60).7 New vessels grow Disease Study (AREDS) Research Although many eyes with drusen from the choriocapillaris into the sub- Group9 has found that, in patients maintain good vision throughout RPE space and later into the subreti- with a high risk of AMD progression life, a significant number of elderly nal space. Leakage or haemorrhage (those with extensive intermediate patients develop decreased central from these vessels leads to serous drusen, or at least one large druse, vision due to advanced AMD. Two or haemorrhagic detachment of the or noncentral geographic atrophy, main types of advanced AMD are RPE and/or sensory retina. Initial or advanced AMD in one eye), recognised – “dry” or non-exudative symptoms include metamorphopsia there was a statistically significant and “wet” or exudative. (distortion of vision) and blurring reduction in the development of Dry AMD accounts for approximately of central vision. Examination of advanced AMD in patients using 90% of cases and typically causes the fundus reveals a grey-green, antioxidants and zinc (see Table I). gradual mild to moderate visual slightly elevated lesion, which is of- impairment over months to years.6 ten accompanied by intraretinal or Table I: AREDS formulation Clinically it is characterised by subretinal haemorrhage and/or lipid sharply circumscribed circular areas exudation (see Figure 4). Vitamin C 500 mg of retinal pigment epithelial (RPE) The haemorrhagic episode is Vitamin E 400 IU atrophy with varying degrees of cho- followed by a gradual organisation Beta Carotene* 15 mg riocapillaris loss at the macula. Later of the blood and eventually the Zinc 80 mg on, larger choroidal vessels become formation of a fibrous disciform scar Cupric oxide 2 mg prominent within the atrophic areas at the fovea (see Figures 5a and and the pre-existing drusen disap- 5b).