Scheduling the Appointment
Depending on the clinic setting, the content and format of a low vision assessment will vary. For example, in a hospital eye service (HES) clinic, fundus examination will often have been performed in a separate clinic, so the low vision assessment comprises only history, visual assessment, refraction, prescription of magnifiers and advice. In some third-sector clinics there may be a rehabilitation worker or eye clinic liaison officer (ECLO) present, so the low vision practitioner can pass some discussions onto this other professional. For the purposes of this chapter, it will be assumed that the patient has already received appropriate ophthalmological care, is aware of their diagnosis, and that their ocular health has been assessed recently.
In community optometry practice where the practitioner is responsible for the entire eye examination, it often makes sense for the low vision assessment to be performed on a different day to the eye examination. There are three reasons for this: first, it allows the patient to plan for the low vision assessment and to bring samples of tasks they would like to perform, and any magnifiers or spectacles they have at home. Second, the additional time a low vision assessment takes can prove arduous for the patient. Finally, the bright lights used in indirect ophthalmoscopy, for example, can cause long-lasting dazzle and after-images in people with visual impairment, and it would be unreasonable to then expect reliable measurements of vision to be taken.
Funding of the assessment will also vary depending on the setting. In most hospital low vision clinics, the examination, and loan of optical magnifiers, are provided at no cost to the patient. A similar system exists in Wales: under the Wales Low Vision Scheme, accredited optometrists and dispensing opticians provide low vision assessments and loan optical (and in some cases electronic) magnifiers in community practice without charge to the patient. In other settings, the entire cost of the examination and magnifiers will be provided on a private basis. In this case, it is important that the patient is aware of the examination fee, and likely cost of any devices, before attending the appointment.
It is good practice for the patient to be aware of the purpose of the low vision assessment. Some may not see themselves as visually impaired and, if the purpose of the low vision assessment is not made clear, may choose not to attend the appointment. Others may have unrealistic expectations that medical or surgical treatment will be offered or, more commonly, that a new pair of spectacles will restore their sight. Examples of letters explaining the purpose of a low vision assessment can be found in Appendix 3 .
Preparing for the Assessment
Detailed records must be kept, and a scheme devised for this. Samples of possible record forms to be used with adult and child patients can be found in Appendix 2 , but each practitioner will have their own preferred format. It is unlikely that the usual practice record cards will be suitable: a great deal of information, which is quite different to that usually gathered during an eye examination, must be recorded.
People with low vision are often older adults, and in this age group the frequency of hearing loss is high: more than half of those over 80 years old have significant hearing loss. The examination should be performed in a quiet room, and a hearing loop should be considered. To facilitate lip reading, the practitioner should be well lit and not sit with a light source behind them (such as an illuminated logMAR chart), and all of the information should be explained before the patient removes their spectacles. Even slight visual impairment reduces speech-reading (i.e. the ability to interpret speech using facial expressions and body-language cues).
The room used for an assessment should be uncluttered without trip hazards or obstacles, and where possible it should be on the ground floor. The clinic should be well signposted from the main entrance of the building, it should be easily accessible by public transport, and there should be car parking ( ).
The room lighting should be adjusted so it is comfortable for the patient: people with conditions like congenital stationary night blindness see very little in the dark so a light should be left on whenever possible. Conversely, people with achromatopsia might be extremely light sensitive, so the room light should be dimmed before they enter the room. Patients sometimes ask for the vision chart to be switched off for their acuity test; it is best to politely explain that it is important vision is measured under standardised and repeatable conditions so the chart must be switched on for this test. In this case, make sure it is turned off again after the acuity measurement is completed.
When assessing children, it is usual that a parent or carer is present during the assessment. For adults, it can be helpful for a friend, partner or carer to be present, with the patient’s permission. Family members can be both a considerable hindrance to the patient’s rehabilitation (perhaps trying to take tasks away from them) but are also the greatest help, and a potential partner in the rehabilitation process (e.g. by reminding the patient how to use the magnifier, buying a new reading lamp or repositioning an armchair to be nearer the television). You need to get to know the social circumstances of the patient and meeting the family in this way is very useful. They, in turn, are often confused about the patient’s condition—why can he not read, and yet can see small objects dropped on the floor?—and it is often useful for them to appreciate exactly what the patient’s visual standard really is—why is he registered ‘blind’ when he can still see? You should try and answer their questions, as well as those of the patient, whilst not letting the family become the subject of the assessment: it is the patient’s needs which are paramount. All questions should be addressed to the patient themselves and not to a carer, family member or interpreter.
Make sure that everyone in the room introduces themselves to the patient, including any students or observers.
Of course, some information gathered during your assessment may be very personal medical information, and the person accompanying the patient may only be a casual acquaintance. In this case, the patient may not want that person to come into the consulting room, and this would always be respected. This can be achieved by the optometrist going to the waiting area to collect the patient and asking if they wish to be accompanied: if the patient suggests to their companion that they get some refreshments, or sit and read their newspaper, then the optometrist must be sensitive to this hint and see the patient alone.
Collecting the patient from the waiting area is a useful strategy to adopt, because it allows the first stage of the assessment to begin: the general observation of the patient.
General Observation of the Patient
This begins when first seeing the patient in the waiting room and continues throughout the assessment. It should include the following points:
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What are they doing in the waiting room? If they are reading a book or looking at their phone, note what distance they are holding it at, whether they seem to be relying on one eye, and what spectacles or magnifiers they are using.
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Are they able to hear your voice when you call their name, and do they make eye contact when you introduce yourself? Do they appear bothered by bright light, perhaps holding their head or eyes down, screwing up or shading the eyes, wearing a hat with the brim pulled down, or tinted spectacles? This suggests that the use of tints or visors, or a typoscope when reading, may need to be considered.
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Can they travel from waiting room to consulting room chair alone? Do they navigate easily across the room (suggesting moderately spared peripheral vision) alone, or do they hold their companion’s arm? Can they find and position themselves in the chair easily? You need to be prepared to help the patient here and should know how to guide the patient using a ‘sighted guide technique’ (see Chapter 15 ). You would ask the patient to grasp your arm just above the elbow, and they would then follow you. If you pass through a door, the patient should be on the side on which the door is hinged so that they can hold it as you both pass through. You should also be offering a ‘running commentary’ in describing the route to them (‘We are just approaching two steps up’; ‘We are going to turn into the next door on the left’). When you arrive at the consulting room, tell them where the chair is and what colour it is. If they have been walking unguided, note their ability to locate it. If you are guiding them, take them to the chair and stand facing it, and place their hands on the arms of the chair. From this they will be able to determine the position of the seat. If the patient or their carer does not seem familiar with correct ‘sighted guide’ procedures, then the opportunity may be taken later to suggest how it may help them.
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Do they have an obvious tremor, or limited movement? This may limit the range of tasks which they are able to perform, or the type of low vision aids they will be able to manipulate.
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Do they look directly at you when talking, or do they appear to view eccentrically? If they appear to be eccentrically viewing, does it seem to be by adopting one consistent direction?
Case History
This has been described as the most important part of a low-vision assessment. It is essential to find out exactly what the patient needs and wants, and what they are expecting you to do for them: you must also use this opportunity to build a rapport with them. At the end of this appointment you will be asking them to trust your advice and recommendations, and these may not be exactly what they wanted to hear. Ask the person what they would like to be called, for example, Dr Smith or Mary? Allow the person to lead the conversation a little, so that you can get a sense of what they are most interested in and what is important to them. Try and avoid the ‘interrogation’ technique of repeated closed questions.
Each practitioner will adopt their own opening question (the authors’ are: ‘Tell me about your eyesight at the moment’,‘What brought you here today?’ and ‘How long has your vision been affecting what you can do?’).
Helpful guidelines to conducting a successful assessment are:
- 1.
Begin the examination with easy and familiar questions, such as name, date of birth, telephone number. This allows a gross assessment of the patient’s mental faculties and memory and gives the patient the opportunity to gain confidence in recognising your speech. Speak slowly and in short sentences, seeking frequent responses to be sure the patient has understood.
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Do not randomly and repeatedly change the subject of your questioning, and when you change topics try to signal and emphasise to the patient that you are now going to talk about a different subject. This is particularly important when you are asking something personal, when a bridging phrase like ‘I’m now going to ask about your family situation’ can help.
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Encourage the patient by words or sounds, rather than gestures such as nodding your head.
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If you wish to make it clear that you are addressing the patient rather than someone else in the room, address them by name.
This history is inevitably going to take a little time: the patient must not feel rushed, or afraid to raise any matter which concerns them. It is important to explain the rather personal nature of the questions that will be asked about their everyday life, and the reason why these are necessary. It is usually better to go through the full range of questions before beginning the examination, but if answers seem contradictory or the patient becomes restless, you may wish to move on and return to some of the questions later. The topics to be covered should include:
- 1.
Duration of condition and onset. The question ‘how long have you had problems with your vision’ can produce a long account of every pair of spectacles prescribed, so ‘when did you start having difficulties managing with your spectacles’ can often be more productive. If the condition is very recent the patient may be too upset to accept any assistance, whereas if the condition has been present for many years, they may have developed nonvisual methods and again be unmotivated to use their vision. The patient might associate their vision loss with some traumatic event such as a bereavement, illness, burglary or fall, even though this will rarely be the direct cause of their vision impairment.
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Stability of condition and difference between the eyes. If the vision is constantly changing then you might need to consider a variety of different approaches for different days. Ask whether the day of the assessment is a ‘good day’ or a ‘bad day’ for them. If the patient feels one eye is significantly better, you need to confirm that this is the case, and then concentrate on maximising the vision of that eye.
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Patient’s knowledge of condition and prognosis. It is unlikely that the ophthalmologist has deliberately withheld information from the patient, but the patient might have forgotten or misunderstood what they were told. As well as finding out what pathology is present, this also gives you a guide to the patient’s capacity to remember details accurately: you may well be giving them instructions related to magnifiers later which you will require them to remember when they arrive home, or be asking them to make contact with a local service.
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Ongoing hospital monitoring and/or treatment. It is essential that any patient who has not had medical assessment of their visual impairment should be referred, as should the patient who appears to have deteriorated significantly since their last visit to the ophthalmologist. In your enthusiasm for prescribing magnifiers, do not forget that medical or surgical treatment may be appropriate, although you may consider prescribing something temporarily.
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Registration status. As discussed previously, eligible patients are often not registered. This should be encouraged whenever possible as the best way to make them aware of the range of services available to them, and to help the societal impact of visual impairment to be measured.
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Education and/or employment, in the past, at present and in the future. This will be a major factor in defining the patient’s requirements. If an adult patient was visually impaired during childhood, find out whether they learned touchtyping and Braille. If not in employment at present, find out what job the patient left, and why, and if they wish to return to it. Include voluntary and unpaid roles and remember that a ‘retired’ patient may still be involved in their previous profession: a retired accountant may, for example, want to work for friends and relatives occasionally. Experienced practitioners would never assume that a patient in their 90 s has stopped work! Do they have caring responsibilities?
- 7.
What hobbies and other activities do they enjoy? Have they had to stop doing these because of their vision loss?
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What is their home situation? Do they live alone, or with family? Are they a carer themselves? Find out whether people the patient live with have good vision, and whether they can drive or help with correspondence. Do they own their flat or house, or is it rented from the council or a housing association? This will affect the provision of altered lighting or other adaptations. If they live in a flat, find out whether it is on the ground floor—if not, is there a lift?
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Present aids and spectacles. It is important to find out what the patient has already, if it is successful, what it is used for and how it is used. It may be that spectacles which are not worn at present may be useful in conjunction with an aid, or that a magnifier which is ‘no use’ is being used incorrectly. Spectacle prescriptions should be determined and recorded, and magnifiers described as accurately as possible. If there is no label on the magnifier, its equivalent power could be accurately measured if required (see Chapter 7 ), but within the constraints of the assessment it is sufficient to obtain a general indication. This can be judged from the size of the lens: in general, the larger the diameter of the lens, the lower will be the power. A better indication can be obtained by imaging a distant light target through the lens onto a surface below: this could be done by moving the lens into a position where it creates an image of the ceiling light-fitting on the desk ( Fig. 17.1 ). The image distance from the lens to the desk is now approximately equal to the focal length (if the object is assumed to be at infinity), and this distance can be estimated. The reciprocal of the distance in metres is the power of the magnifier in dioptres.
