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Monthly Archives: March 2013

iPads and vivas

Posted on March 23, 2013 by phil Posted in academia, geekery, optometry

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Leaving aside that the term viva is a bit of a funny one (the important bit of viva voce is missed out; I’m sure it should be pronounced v-eee-va and not v-eye-va; there was a now-considered-hilarious 1970s car of the same name) this oral examination is a key part of the postgraduate research assessment process. In the UK at least, it remains essentially the only way in which the work of a PGR student is examined.

To head off on a brief tangent, this is not the case in Australia or the United States. In the former, at least in my direct experience, three external examiners receive copies of the final thesis and provide detailed written comments which go to a panel which gathers all the opinions and comes to a final verdict.

Students in the US defend their work but this part of the process can be something of a formality and it’s perhaps not quite the same as the traditional see-the-whites-of-their-eyes all-or-nothing high adrenaline British method.

Anyway, the approach I have used myself over the years as an examiner is to read through the weighty tome and make various comments in a separate word processing file and perhaps add various Post-It notes into the thesis to keep track of the key pages. This method comes with a large administrative overhead. For example, you are obliged to type something like ‘Change the term ‘staining of the corneal epithelium’ to ‘corneal epithelial staining’…’ in your list of recommend amendments. Repeat. Many times. It’s burdensome and it does my head in, as the kids say.

Last week I had the opportunity to run the whole process on my iPad. Theses are now routinely provided to examiners as PDF files, and so it was a simple process of using a PDF annotation app (I’m currently using iAnnotate but there are lots available) to work through the report, making edits, adding comments and so on. It was a breeze to work through these during the viva because the program has a button which allows you to advance sequentially through the edits. Extra thoughts and ideas were noted as we discussed the work and it all ended up added into the PDF.

At the conclusion of the process, the student needs to see the examiner comments and again, it was trivial to email a copy of the comments and edits. In fact, the automated email included the annotated PDF and a separate list of each change. This is much better for the examiners, but also an improved situation for the student who receives a more informative list of changes more rapidly.

New VA rules for bus and lorry drivers

Posted on March 13, 2013 by phil Posted in optometry

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The DVLA has just announced some new health-related rules for drivers. For car drivers, there is a new stipulation regarding epilepsy; however, for bus and lorry drivers, visual acuity requirements have been relaxed.

Previously the threshold was 0.8 (6/7.5) in the better eye and at lease 0.5 (6/12) in the poorer eye. These values are now 0.8 and 0.1 (6/60), respectively.

Driving is an unusual visual task inasmuch as there are large eye movements than in most everyday tasks. It might be that with the specific angles of wing- and rear view-mirrors, there are different implications for ‘poorer right’ and ‘poorer left’ drivers, and they might notice a difference between right-hand and left-hand drive cars.

Overall, though, it seems this is all of little functional consequence. This 1991 paper suggests little or no practical difference between monocular and binocular drivers.

The inflammatory response and contact lens-associated keratitis

Posted on March 12, 2013 by phil Posted in lectures, optometry

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Understanding the inflammatory response of the cornea during contact lens wear is one of the remaining major challenges for researchers and the contact lens industry.  This lecture outlines the pathophysiology of inflammation and its relationship to contact lenses.  Relevant resources for this talk are shown below.

Manchester Collaborative Centre for Inflammation Research (MCCIR)

Inflammation on Wikipedia

Is contact lens wear inflammatory?

Assessment of stromal keratocytes and tear film inflammatory mediators during extended wear of contact lenses.

In vivo confocal microscopic evaluation of langerhans cell density and distribution in the corneal epithelium of healthy volunteers and contact lens wearers.

Clinical characterization of corneal infiltrative events observed with soft contact lens wear.

Adverse events and discontinuations with rigid and soft hyper Dk contact lenses used for continuous wear.

Multicenter case-control study of the role of lens materials and care products on the development of corneal infiltrates.

Incidence of keratitis of varying severity among contact lens wearers.

Rethinking contact lens associated keratitis.

The size, location, and clinical severity of corneal infiltrative events associated with contact lens wear.

Contact lenses and other risk factors in microbial keratitis.

The Incidence of Contact Lens-Related Microbial Keratitis in Australia.

Risk factors for acanthamoeba keratitis in contact lens users: A case-control study.

Refractive error and corneal curvature

Posted on March 12, 2013 by phil Posted in optometry

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An interesting question arose in our contact lens clinic last week: are myopic corneas steeper than those of ametropes or hyperopes? Anecdotally, it was felt that perhaps myopes had flatter corneas. Most optometrists should be aware that most refracts errors are axial: myopes have big eyes and it’s the reverse for those who are longsighted. However, myopes having flatter corneas would be counter-intuitive.

Ametropia can be due to a normal length eye hosting a cornea that’s the wrong shape (too steep or too flat). However, I wasn’t sure if this was a general trend – do myopes tend to have steep corneas?

So, to the literature. This paper describes a study in Taiwan of 500 subjects aged 40 and over. The authors measured a range of ocular parameters and whilst a strong (ish) correlation was found between refractive error and axial length (r-value -0.65), no such relationship was demonstrated between refractive error and corneal curvature (r = -0.02). Overall, then, randomly selected hyperopes will have similar corneal curvature to a group of randomly selected myopes.

A slightly different story arises from this very large study from Canada. This work, on over 3,000 eyes finds a general increasing of corneal power with more myopia. It’s not a very strong relationship (r = -0.25) but it’s the sort of finding you can get with large data sets.

So, our anecdotal feeling-in-our-water was incorrect. Overall, myopes do have steeper corneas, but it’s a rather weak relationship and they are much more likely to have longer eyes.  Predicting K readings from refractive error for an individual is unlikely to be accurate.

UK optometrists and journal access

Posted on March 11, 2013 by phil Posted in optometry

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Anecdotally, it seems the optometrists who are members of the College of Optometrists are generally unaware that they have access to 28 scientific journals as part of their membership package.  This access is processed via the Athens system where organisations and institutions purchase access rights for their members or staff to specified journals within the academic literature.

College members have access to a range of optometric, ophthalmological and contact lens titles, including the College’s own title Ophthalmic and Physiological Optics, Optometry and Vision Science, Investigative Ophthalmology and Visual Science and Contact Lens and Anterior Eye.   Those wishing to gain access need to contact the College’s Library Manager as explained here.

Like getting through to Noel Edmonds

Posted on March 10, 2013 by phil Posted in geekery

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I’m not a huge podcast listener.  I find that they can be rather hit and miss; ones which I initially enjoy can quickly become irritating for reasons I can’t quite work out.  ‘In our time’ went that way, so I’m looking at you, Melvyn Bragg.  What should be a good listen ended up irking me.  Something about its overly cheery, bumbling Londonness wound me up in the end.

My podcast subscriptions are down to four and there are only two to which I listen immediately after release: The Tuesday Club in which Alan Davies and his mates go on about Arsenal for an hour each week or so, and Mac Power Users where two American lawyers explain their use of their Macs and iOS devices in excruciating and fascinating detail.   As a 20+ year full time Mac user, I thought I knew quite a bit of stuff, but I’ve learned a lot from these two presenters.

So, I was excited like a kid getting through to Noel Edmonds on Swap Shop when I received e-mails from both of them this week.  Given their password management methods (leaving everything do a password management program called 1Password) it occurred to me that you can’t actually leave everything to this one program.  You need to remember the password for 1Password for example.  So, in the feedback bit of their website I enquired about this and they each took the trouble to write to me (or ‘write me’ as they routinely say it on the podcast).

They seem to think that you need to actually remember the password for 1Password, for Dropbox (if you use it to sync your passwords) and your Apple ID.  I reckon you need to remember your e-mail password too.

Remember: 01 811 8055.

 

The future of contact lenses

Posted on March 10, 2013 by phil Posted in lectures

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This lecture reviews the current state of contact lenses and what is to come.  There is much to do.  Future changes include improving wearer comfort, radically different presbyopic lenses, improving infection and inflammation rates, slowing myopia progression.  Maybe we will also see drug delivery and heads-up displays through contact lenses.

The following links are to materials related to my talk.

Discontinuation of contact lens wear: a survey.

Effect of daytime lens replacement on soft contact lens related discomfort.

Lid wiper epitheliopathy and dry eye symptoms.

Friction measurements on contact lenses in their operating environment.

Dynamic Contact Angle Analysis of Silicone Hydrogel Contact Lenses.

A Novel On-Eye Wettability Analyzer for Soft Contact Lenses.

Refractive errors in medical students in Singapore.

Prevalence of refractive error in the United States, 1999-2004.

Effect of dual-focus soft contact lens wear on axial myopia progression in children.

Optical treatment strategies to slow myopia progression: Effects of the visual extent of the optical treatment zone.

Protective effects of high ambient lighting on the development of form-deprivation myopia in rhesus monkeys.

Is contact lens wear inflammatory?.

Short-term physiologic response in neophyte subjects fitted with hydrogel and silicone hydrogel contact lenses.

An international survey of contact lens prescribing for presbyopia.

PixelOptics

Google Glass

Menicon magic lens

Dropbox

Posted on March 9, 2013 by phil Posted in geekery

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The honour of the first post goes to Dropbox. This first widely-used cloud service is now a must-install on all newly configured computers, tablets and phones (surely).

It evidently has a powerful API given the number of services which piggyback on its fast syncing capabilities. 1Password comes to mind, amongst others.

So, raise a geeky glass to Dropbox. King of the Cloud.

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