Eye on Eyes: Irlen Syndrome, VEGF inibitors and a TED talk to guide better science

25 05 2013

Dear Readers:

This edition is a shift from the regular.  In conversations with colleagues and optometry forums I’ve decided to share some of the current conversations being had in optometry, ophthalmology and in medicine.  In this edition, I discuss Alberta’s Bill 204 which is a pending act that brings vision therapy and behavioural optometry into the spotlight.   Retina online published an interesting look at the incidence of nonfatal MI’s and how VEGF inhibitors may increase patient risk.  Finally, for those that know me know my frustration with faulty science and ‘counterknowledge,’  I share a video and encourage practitioners of all disciplines to look at Ben Goldacre’s TED talk on the subject.

In good health,

RM

Irlen Syndrome Testing Act Bill 204 in Alberta Legislature Second Reading

My friend and colleague Dr. Chris Schell (http://www.optometristbarrie.ca/) brought up an interesting piece of legislation in the Alberta government with respect to early learners eye screening.  This bill, also known as the Irlen Syndrome Testing Act, will call for School Boards to make available screeners for Irlen syndrome (including scotopic sensitivity syndrome and visual disturbance syndrome).

Section 3 is quoted below:

3(1) A teacher who recognizes symptoms of Irlen Syndrome in a student must recommend to the parents or guardian of the student that he or she be tested for Irlen Syndrome.

(2) Upon receiving written consent from the parent or guardian of a student, that student must be tested by a screener who is made available by a board under section 2.

(3) If a screener determines that the student may have Irlen Syndrome, the screener must advise the parent or guardian and indicate what corrective measures may be undertaken and if additional testing is required.

This bill is certainly an interesting step in the broader acceptance of vision therapy, however the increasing information on Irlen Syndrome  calls into question the syndrome itself.  Schiemann et al. has demonstrated that there is significant overlap in symptoms of Irlen syndrome patients and the majority (95%) have unresolved binocular vision and refractive anomalies (J Am Optom Assoc, 1990).  The ‘success’ of Irlen filters may be in fact indicative of  more specific binocular vision syndrome and the improvement by filtered lenses may be more of a provocative test than a treatment in my opinion.  So although the bill is well intentioned, I fear the shoulder’s that it is being rested on.

Click here to See Bill 204

Myocardial Infarctions following Intravitreal VEGF Inhibition
(Retina Online Vol 9 No. 5)

The authors of the following study sought to determine the risk of thromboembolic and gastrointestinal bleeding events in the 12 months after injections of bevacizumab or ranibizumab compared with photodynamic therapy (PDT) and a nontreated community sample.

They examined hospital and death records for 1,267 patients treated with vascular endothelial growth factor (VEGF) inhibitor and 399 patients treated with photodynamic therapy (PDT) attending Western Australian eye clinics from 2002 to 2008, and 1,763 community controls, aged ≥50 years. They also analyzed hospital records from 1995 to 2009 for history of myocardial infarction (MI), stroke and gastrointestinal bleeding before treatment. They searched records for evidence of these events in the 12 months after treatment.

The 12-month MI rate was higher for VEGF inhibitor patients than PDT and the community group (1.9/100 vs. 0.8 and 0.7, respectively), the authors reported. They observed no differences between patients treated with bevacizumab and ranibizumab, and the noted that the adjusted MI rate was 2.3 times greater than the community group (95% confidence interval, 1.2–4.5) and PDT rate (95% confidence interval, 0.7–7.7). The 12-month MI risk did not increase with the number of injections administered (hazard ratio, 0.9; 95% confidence interval, 0.5–1.5). Stroke and gastrointestinal bleeding did not differ between any exposure groups.

Although all of the adverse events examined were rare, patients treated with VEGF inhibitors were significantly more likely to experience fatal or nonfatal MI than the community group, the study authors determined. This increased risk may be related to the underlying age-related macular degeneration or vascular endothelial growth factor inhibitor use itself.

Source: Kemp A, Preen DB, Morlet N, et al. Myocardial infarction after intravitreal vascular endothelial growth factor inhibitors: a whole population study. Retina. 2013;33(5):920–927.

 Bad Science – a TED talk on Practicing Mindful  Medicine and Steering Clear of Counter-science

“It was the MMR story that finally made me crack,” begins the Bad Science manifesto, referring to the sensationalized — and now-refuted — link between vaccines and autism. With that sentence Ben Goldacre fired the starting shot of a crusade waged from the pages of The Guardian from 2003 to 2011, on an addictive twitter feed, and in bestselling books, including Bad Science and his latest, Bad Pharma, which puts the $600 billion global pharmaceutical industry under the microscope. What he reveals is a fascinating, terrifying mess.

Click the image to view


TEDBENGOLDACRE

 

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