Elderly Eyes - Normal Changes PDF

As patients age, their eyes and surrounding structures undergo a number of changes. Some of these are of considerable concern to patients and occasionally they require optometric or specialist review. More often, patients can be helped by either reassurance that there is nothing seriously wrong or t...

As patients age, their eyes and surrounding structures undergo a number of changes. Some of these are of considerable concern to patients and occasionally they require optometric or specialist review. More often, patients can be helped by either reassurance that there is nothing seriously wrong or the prescription of very simple measures. Included in this document Problems Management Referral to an optometrist Key Points Problems Changes in appearance A number of changes occur as the eye ages (Fig. 1). The eyes become less 'white and bright'. The cornea becomes less transparent and the sclera more yellow and 'bloodshot'. Some patients develop dark areas in the sclera where the sclera thins adjacent to the extraocular muscle insertions. Most elderly patients develop arcus senilis. Fat accumulates beneath the conjunctiva in the area between the open eyelids and adjacent to the cornea, i.e. where pterygia form in younger patients. The pupil becomes smaller and does not dilate much in darkness. The lens becomes a little opaque and this ‘yellows’ the normally empty black pupillary space. Small subconjunctival haemorrhages are common. Changes also occur in the eyelids and orbit (Fig. 2). Laxity and stretch lines develop in the skin around the eyes. The eyelids loose their elasticity, the medial and lateral canthal tendons stretch and the eyelids tend to sit lower. Some patients develop a senile ptosis. Chronic use of the frontalis muscle to elevate the upper lid results in permanent forehead wrinkles. Atrophy of the orbital fat results in a deep sulcus above the eye and fat herniation from the orbits into the lower (and often the upper) lids creates ‘bags’ under the eyes. Fig. 1. The eye of an elderly patient. The Fig. 2. The eyelids and orbit of an patient has arcus senilis and the conjunctival elderly patient. The patient has a vessels are prominent. An area of scleral senile ptosis and is using the frontalis thinning is visible just anterior to the muscle to elevate the upper lid. The insertion of the medial rectus. Lashes are lower lid rides low and there is a deep sparse and the lids are crusted. sulcus above the globe due to orbital fat atrophy. (Photo courtesy Dr D. Peart) Changes in comfort Many elderly patients complain that their eyes ‘just don’t feel right’. This should not be dismissed as just getting old. Most of these patients will have a specific low-grade problem such as dry eye or blepharitis. Presbyopia Accommodation is the ability of the natural lens of the eye to increase its power in order to view near targets or overcome hypermetropia. Presbyopia, literally ‘old-eye’, is the term used to describe the progressive loss of ability to accommodate that becomes symptomatic from approximately 45 years of age. Patients experience presbyopia as a difficulty seeing near objects clearly or having to exert an effort to keep it clear. Prolonged near work gives rise to asthenopia or ocular dis-ease. The classic symptoms of presbyopia are the complaints ‘I have to hold things further away to see them clearly’ and ‘My arms don’t seem long enough anymore’. In fact, loss of accommodation begins early in life but it is only later in life that the loss starts to impact on visual function. The age of onset varies according to both the refractive state of the patient and whether this is corrected, and the near vision tasks a patient performs. Uncorrected myopes have a natural ability to view near objects and so experience presbyopia later. Uncorrected hyperopes use some of their accommodative ability even to see distant objects and so become presbyopic earlier. Changes in refraction In later life the refractive state of the eye often changes. In most patients this is a benign process. In a few it may be due to diabetes or the development of cataract. The development of nuclear cataract can cause the eye to become myopic and near vision may improve. Patients so affected are delighted that they no longer need their reading glasses but most miss the fact that that they can no longer see well in the distance. Non specific visual loss Most elderly patients are aware that they cannot see as well as when they were younger even if their acuity is good and they are free from ocular disease. The aging lens transmits less light and the retina becomes less sensitive. It is thus 'normal' to suffer a mild loss of visual acuity and colour perception. Corrected vision of 6/6 or even 6/9 can be ‘normal’ in older eyes although many patients can see much better and so reduced acuities should not be accepted until reversible changes such as refractive error and lens opacities have been dealt with. A very important problem is loss of contrast sensitivity. Contrast sensitivity is the ability to detect shades and contours. Testing Snellen acuity misses loss of contrast sensitivity because this is a test of black on white, i.e. 100% contrast, rather than of varying shades of grey. Cataracts can affect contrast sensitivity without a loss of Snellen acuity. Patients with poor contrast sensitivity have difficulty seeing curbs and steps and find poor quality print, such as newspapers, very difficult to read. Glare Older patients are particularly sensitive to glare and many find it difficult to see in bright sunlight and at night. In most cases this is due to early cataract. Cortical (peripheral) lens opacities give rise to glare when the pupil is dilated, for example, when driving at night. Posterior sub capsular cataracts cause glare when the pupil is small, for example in bright sunlight. Dark adaptation and glare recovery The eye's ability to adapt to changes in ambient light levels is achieved by changes in the pupil size and neural and biochemical changes in the retina. All of these facilities are affected by age, making it increasingly difficult for patients to enter a room darker than the one they are leaving or recover from the glare of car headlights when driving at night. Floaters and flashes Most people are aware of 'physiological' floaters, for example when looking at a featureless background such as the sky. These are due to the shadows cast by small opacities in the vitreous. As people age the vitreous becomes more fluid, these opacities move more readily and the floaters become more of a nuisance. Around the sixth decade the vitreous falls forward (posterior vitreous detachment) and collapses. This can give rise to large floaters that can be very symptomatic and the detachment process can cause a retinal tear or detachment. In general, longstanding floaters are benign. New floaters, especially those accompanied by other symptoms such as flashes, failing vision and field loss are likely to herald a sinister problem such as a retinal detachment. Photopsia (flashes of light) is common in the elderly and many patients see flashes just after turning off the lights at night. These are due to retinal stimulation by an increasingly mobile vitreous. In general photopsia occurring in the dark or at night is almost always benign. The dark-adapted retina is very sensitive to stimulation by the vitreous. When patients complain of photopsia, enquire carefully about other symptoms, in particular those of migraine and retinal detachment. Isolated photopsia during the day is almost always a sinister symptom of vitreous or retinal detachment. Management The first task is to distinguish ‘normal’ aging from significant pathology and it is important not to dismiss a patient's symptoms until you have taken a history and examined the eyes. Remember that common things are common. The commonest causes of irritable eyes are dry eye syndromes and blepharitis. The commonest causes of blurred vision are uncorrected refractive error, cataract and macular degeneration. Reassurance Many patients just need reassurance that there is nothing sinister going on. Discuss the normal changes that take place as the eye ages. Reassure your patient that using their eyes will not 'wear them out' and that most causes of visual deterioration will not result in blindness or loss of independence. Lubrication and decongestants Patients with chronically red eyes or uncomfortable eyes should avoid dry and smoky environments and alcohol. Try prescribing a tear substitute. Decongestants such as Albalon can be used to whiten the eye for special occasions such as a family portrait or wedding. Pragmatically, advise patients to start with the cheapest artificial tears they can buy and experiment. The need to use them more than six times a day suggests that either the patient does not have a tear deficiency, or that they have very dry eyes. Refer such patients. Lighting advice Many elderly patients have visual difficulties because their homes are poorly lit. Reading light should be as bright as  possible and come from behind, ideally over the reader’s shoulder, so as not to cause reflections and glare. Tell the patient to experiment with the position of their reading chair, TV, reading light etc. It is important not to have light sources near the line of sight while watching TV. Advise patients to ensure they have the brightest possible (limited only by size and safety warnings) light bulbs in every overhead and standard/angle-poise lamp. Some people need reassurance that this will make essentially no difference to their electricity bill. In some cases, important reading is best done at certain times or places, the exact time and location depending on the orientation of a patient's house. For example, if a patient usually reads in a room with a west-facing window, it is usually easier to read in that room in the early afternoon. Hobby specs Many patients with presbyopia simply need a pair of cheap hobby specs but they also need regular ocular review by an optometrist or ophthalmologist who can screen for eye diseases such as glaucoma. Advising patients with presbyopia to buy a pair of hobby specs at The Warehouse or a chemist is reasonable, but also tell them that they still need to have their eyes examined every two to three years. Referral to an optometrist Patients with symptoms of presbyopia and blurred vision, particular if the vision improves with a pinhole, should be referred to an optometrist. Optometrists are an underused resource by some GPs, who may feel more comfortable turning to medical colleagues for help. However many of the ocular problems of the elderly can be solved by this profession. Indeed most ophthalmologists turn to optometrists for help in solving the complicated spectacle needs of elderly patients with failing vision. Optometrists can maximise the corrected vision, give advice on a number of problems such as blepharitis and dry eye and are good detectors of serious diseases such as glaucoma and macular degeneration. They are also usually easier to access, in terms of location, waiting time and cost, than ophthalmologists. Some optometrists specialise in low vision caused by macular degeneration and can advise on, and provide, magnifiers, high power spectacles and lighting devices. Key points GPs play a vital role in the management of normal age related changes in and around the eye. Many patients just need reassurance or simple advice on issues such as lighting. Refer patients with longstanding or slowly progressive visual problems to an optometrist. © GP Eyes - Dr Malcolm McKellar 2011