For low vision specialists and those who consult them
September 29, 2010Posted by on
Here is the first of my reports from Envision 2010, concentrating on the research sessions.
Envision has really increased the profile of its research sessions recently and this is reflected in the number of people who were presenting new findings at this meeting. Although the organisers hope that there will be overlap between clinical and research sessions at the meeting, in my experience most of my academic colleagues spent 90% of the conference in the research stream with only occasional forays into the more clinical sessions.
The session I most enjoyed was the discussion on cortical reorganisation in macular degeneration. This session, moderated by Gordon Legge, included people with very different views on the extent to which the primary visual cortex changes in macular disease. Chris Baker from NIH (and formerly the Kanwisher lab in Boston) opened proceedings by presenting functional MRI data showing that the lesion projection zone in primary visual cortex did show activation in people with advanced macular disease. Another speaker, Tony Morland from the University of York (UK), showed that this did not occur in the cohort of people he studied, and presented some possible explanations for the cortical activity measured by other groups. The remaining speakers maintained the high level of the presentations and debate was lively throughout the session.
Other research sessions I particularly liked were the discussion on perceptual filling-in chaired by Walter Wittich from Montreal; the reading session moderated by Don Fletcher; and the Quality of Life session chaired by Bob Massof.
The most interesting new data I saw were those presented by Ava Bittner who looked at variability in quality of life experienced by people with retinitis pigmentosa. I also enjoyed the data which Don Fletcher presented on the perception of scotomas by people with macular disease: he showed that only 1 of 108 people perceived their scotoma as a black portion in the centre of their vision (and this one person only noticed it when first waking up before moving her eyes). It really is time people stopped using the NIH picture of AMD as an example of this condition.
September 21, 2010Posted by on
There seem to be a large number of low vision conferences coming up in the next few months, including Vision 2011 in Kuala Lumpur next February (the largest low vision conference in the world, held every three years). However, I’m still looking forward to Envision this week.
Regular readers of the blog will know I enjoyed Envision last year (see my report here). For me as a someone who divides my time between clinical and scientific work it’s a nice mix of these two disciplines. Whilst the scientific sessions aren’t as likely to present breaking research news on gene therapy trials as a conference like ARVO, the scientific programme has certainly improved in the last few years and is now fairly strong.
I am particularly looking forward to the scientific session on Filling-In (I am speaking in this session, but am looking forward to hearing the other speakers – I’m not being egocentric!). Other scientific sessions which catch my eye are the session on Cortical Reorganisation in Macular Disease chaired by Gordon Legge; and the session on Retinitis Pigmentosa chaired by Olga Overbury, which discusses sleep disorders and emotional aspects of RP.
The clinical sessions which stand out for me include a session on Vision Rehabilitation in Glaucoma led by Mary-Lou Jackson, as I think glaucoma is an often overlooked disease in low vision clinics. The “Clinical dilemmas in visual impairment” event on Friday morning also sounds very interesting.
I’m looking forward to finally seeing the “Going Blind” movie as well.
Envision is a very ‘connected’ meeting – you can follow it on Twitter @envisionconf and you can of course read my report here next week. I hope to see some of you in San Antonio!
September 8, 2010Posted by on
I received an email from the Macular Disease Support this week advertising a new lamp for people with macular disease to use when reading. Apparently it’s the result of “10 years research” and is “very affordable” (although at $140 +$20 shipping I’m not so sure).
Apparently this light “meets all requirements for best vision” and the advert links to a pretty picture of text shown under different types of light. The print under this light does indeed look clear. However, no careful scientific analysis of reading with macular disease has found any effect of lighting type on reading performance (see, for example, this paper by Frank Eperjesi). What is known is that many people with low vision have far poorer light at home than is available in low vision clinics (see this classic paper.
The message which we tell people time and time again in the low vision clinic is: the important thing isn’t the light itself, it’s where you position it (as close to the task as possible, ideally shining from over your shoulder). If someone has $160 spare to spend on lights – and not everyone with macular disease will have this disposable income – they would be far better spending it on 5 lamps which can be moved near to the task in each room of the house (one in the kitchen for recipes and food packets; one in the bedroom for reading at night, and so on).
I am sure some people will prefer the white LED in this light to a compact fluorescent or tungsten bulb, but there is no evidence that people with MD will systematically prefer this light. I have nothing against this lamp design – indeed it looks quite pretty – but wish that people wouldn’t encourage people to buy an expensive product based on their own experience rather than on scientific evidence.
September 2, 2010Posted by on
I suppose there’s no point in having a blog if you don’t occasionally use it for self-promotion, so here’s a link to a paper we have just had accepted in Investigative Ophthalmology and Visual Science.
In it, we asked people with macular disease to observe a point target, and used the MP-1 microperimeter to determine which part of the retina people used to do this. We then asked the same people to look at some words which appeared on the same screen. By using some quite advanced statisics, we compared whether the same part of retina was used for both tasks.
We found that all of our subjects used different parts of the retina for these two tasks. Often they were not very far apart, but it was statistically clear that they performed these tasks differently.
Why does this matter? Well, it teaches us a little about eccentric viewing in macular disease, and shows that people don’t necessarily do the same thing when looking at a word as when they look at a target. It means that we can’t really assess how well people use eccentric viewing if we just ask them to look at a light and check which bit of retina they use for that, for example. It also shows that the MP-1 microperimeter can be used for fixation analysis in this way.
Any comments welcomed!
August 13, 2010Posted by on
The clinic was extremely impressive: as you’d expect the facilities, clinical care and staff were all very good indeed. It was interesting to hear exactly the same conversations between optometrist and patient taking place 4,500 miles away from where I usually practise (admittedly in central London I rarely meet horse veterinarians or cowboys, though). Whilst in many ways the Mayo and Moorfields clinics are similar, both in terms of our patient population and our way of working, I certainly picked up some ideas from the Mayo clinic which we can introduce into the Moorfields low vision clinic in London and will be discussing these with our head of department on my return. I hope that I can return the favour for other low vision practitioners visiting London.
August 6, 2010Posted by on
I have previously written on the use of the Sony Reader and Amazon Kindle as low vision aids. Of course the new ‘must-have’ gadget is the iPad. I have had several patients who have mentioned how useful their iPad is and how easily they can read with it, but have not yet had chance to systematically play with one.
Apple have also rolled out the iBook software to the iPhone. Again, I have not had chance to look at this with a photometer yet, but here is a ‘quick review’ of what iBooks are like for the visually impaired user.
On the iPhone, there is a choice of 9 magnification levels and six fonts (Baskerville, Cochin, Georgia, Palatino, Times New Roman, and Verdana). There is also a Sepia mode which reduces the screen contrast but may also reduce glare.
The largest font size on my iPhone 3GS is equivalent to N25 (3.2M): three times the size of newsprint. As a very rough guide, if you can read newsprint at a struggle you will be able to read this size text fluently. At this size you get about 12 words per page, and the screen refresh is fairly quick. It is possible to display text in reversed contrast, although this has to be set in the iPhone settings rather than in the app itself.
Unfortunately, none of the fonts available are proportionally spaced, and the maximum text size of N25 still isn’t great for people with poor vision. However, the backlit screen and increased font size compared to other eReaders means that iBooks on the iPhone appears to be a better choice for people with reduced contrast sensitivity or visual acuity. Of course, every person with low vision is different and I would certainly suggest trying each device before committing to buying one.
A full report on iBooks on the iPhone and iPad will follow in time….
July 29, 2010Posted by on
I saw a 5-year old child with albinism in the low vision clinic this morning. She is going to start school in September, and her mother asked me to give her a list of things she should ask the teacher to do, to help her daughter to see more easily.
Of course, each child with visual impairment should have access to a Teacher of the Visually Impaired or Peripatetic Teacher to assess the child’s performance in the classroom and to create specific advice for the teacher. Nevertheless, I thought it worth repeating my advice below. This girl’s visual acuity was 6/60 (20/200), she had only moderate photophobia, and her near visual acuity was N12.
My advice was:
Things which the school can do to make things easier for **** include:
– Ensuring that she sits close to the board
– Ensuring that the writing on the board is large and bold enough for **** to read, and that the contrast is high (black ink on a whiteboard; white chalk on a blackboard)
– Enlarging text to at least font size 24 for printed work and worksheets [this girl’s near visual acuity was 12 point. An acuity reserve of 2x is the minimum for fluent reading, so I usually recommend at least double the near visual acuity]
– Making sure that she does not have to share books (as she will have to be close to them to read them easily)
– Allowing her to use her glasses, sunglasses, magnifier, binoculars, bookrest, and a hat if needed
– Allowing her to use a thick black pen to write in if this helps her
– Ensuring that **** has access to a large screen computer, that the text and cursor are enlarged to an appropriate size, and that she is allowed to sit as close to the screen as she needs to
– Making sure that there is enough light for **** to see clearly
– Making sure that window blinds are used if the sun is shining towards ****’s eyes (causing glare)
– Ensuring that **** is able to fully participate in all school activities, including sport, play activities and music
I would appreciate comments from other clinicians, teachers and rehab workers about this list: maybe we can create a universal list of items which teachers should consider when they find they have a child with visual impairment in their class.
July 13, 2010Posted by on
There is a nice paper in the most recent issue of Ophthalmology by Janet Sunness and Jaafar El Annan which reminds us of the importance of performing a refraction (spectacle test) for our patients with low vision. This should not be newsworthy to people who perform low vision evaluation routinely, but should emphasise the importance of refraction to our colleagues who do not see many patients with visual impairment.
In the paper, Sunness examines the records of 739 low vision patients newly referred to her clinic. In 11% of them, visual acuity was significantly improved (by more than 2 lines on a logMAR chart) by prescribing them new spectacles.
The authors make the point that people with eye disease often inappropriately assume that ‘new glasses’ will solve all of their visual problems, which is very rarely the case. However, that doesn’t mean that a spectacle test should not be performed for people with low vision: for these 81 patients in Sunness’ practice, visual function is likely to be better (although not perfect) after new glasses are prescribed.
The paper also makes the excellent point that retinoscopy and keratometry can be useful adjuncts to refraction in people with low vision. For this reason, I think it is important that an optometrist (or an ophthalmologist who performs refraction) is an integral part of the low vision multidisciplinary team.
In summary: low vision practitioners should not forget to perform a refraction for all of their clients with low vision. And whilst people with severe eye disease should not expect glasses to solve all of their visual problems, they may find they perform slightly better with an updated spectacle prescription.
June 29, 2010Posted by on
The 2009 journal impact factors have just been released.
This won’t mean much to those readers who don’t publish research, but my post on the last impact factors is the most visited page on this blog – perhaps as people can find this by Googling “ophthalmology impact factors”.
Impact factors (IFs) are a way of comparing different scientific journals. A high impact factor journal is one where papers in that journal are cited more frequently by other researchers than a journal with a lower impact factor. Whilst being cited isn’t a marker of quality – a citation which says “this work is superb” has the same weight as a citation which criticises the work – better journals tend to have more highly cited papers than poorer journals. In the UK, the impact factor of the journals you publish is often used as a marker of your esteem as a scientist.
Anyway, I have summarised the 2009 impact factor of some journals which publish low vision research:
Ophthalmology 5.5 (2nd highest IF in ophthalmology)
Investigative Ophthalmology and Visual Science (IOVS) 3.4 (6th, down from 4th)
Journal of Vision 3.0 (7th, up from 9th)
Retina 2.9 (8th)
British Journal of Ophthalmology 2.9 (9th)
Vision Research 2.3 (18th)
Eye 1.97 (20th, down from 17th)
Optometry and Vision Science 1.53 (25th, down from 22nd)
Ophthalmic and Physiological Optics 1.15 (34th, up from 37th).
The full scores can be found at Web of Knowledge (subscription required, click on “Additional Resources”).
June 23, 2010Posted by on
I was browsing in a second hand bookshop recently and found the proceedings of the ‘International Conference of Workers for the Blind’ held in Oxford, England in 1949. It’s fascinating.
First, the welcome addresses included greetings from Harry Truman, Clement Atlee and Helen Keller, and the united nations had considerable representation. Welfare of ‘the blind’ was of course a very political issue at this time as so many people were visually impaired as a consequence of the second world war.
One of the major resolutions of this conference was the standardisation of blind registration around the world, to recommend that every country has ‘a definition of blindness, to include both the totally blind and all other persons suffering from such defect of vision that they also require special education or special assistance to save them from destitution, and to enable them to share in the economic and cultural life of the nation’ and that a register of blind people is kept. It was also suggested that an international definition of blindness should be established, which has still not been adopted (although most countries have very similar criteria).
I was interested to see that there was considerable debate over whether registration should be compulsory, with a majority of delegates favouring this. I am not aware of any countries which have compulsory registration today as the idea of labelling people without their consent is not liked. Of course, many benefits are only conferred on those who are registered.
Not every resolution was successful: the suggestion that ‘the neutral auxilliary language of Esperanto be used internationally in work relating to the blind’ does not seem to have been widely adopted (perhaps unfortunately!).
Whilst conferences today would not make so many references to ‘the blind’ as these minutes do, many of the themes and discussions are just as relevant today as they were 61 years ago. And the report that a river cruise was ‘unfortunately marred by heavy rain’ isn’t unusual for a meeting held in August in the UK…