m
Recent Posts
Connect with:
Tuesday / May 21.
HomemieventsSuper Sunday at the Big Top

Super Sunday at the Big Top

These days, there’s plenty of pressure on optometrists to be commercially minded. Super Sunday, hosted at The Big Top, Luna Park by Optometry New South Wales/Australian Capital Territory, reminded us all of why we pursued a career in optometry, by delivering a good dose of clinical education and helping us reconcile this bifurcation in practice.

Super Sunday was a timely reminder of the importance of preserving a confluence between clinical and commercial practice. This is especially true when we consider that optometrists in certain states in the US have been expanding their scope – most recently in California, where they are now able to perform IV injections for angiography, collect blood by skin puncture to test for diabetes, and perform skin tests to diagnose ocular allergies.

A presentation by University of NSW School of Optometry and Vision Sciences Clinic Director, Kathleen Watt, on the role of atropine therapy in myopia control, was a highlight of the day. Myopia is the seventh leading cause of blindness and carries associated risks for ocular pathology such as cataract, retinal degeneration, retinal holes/detachment, and choroidal neovascularisation. Controlling this disease progression is arguably more pressing than other ocular conditions because myopia affects patients at a younger age.

The American Academy of Ophthalmology’s meta-analysis in 2016 compared interventions for myopia control and found low dose atropine to be the most viable option – having limited side effects, avoiding the cost, stigma, and complexity of contact lenses/orthokeratology, and limited effectiveness of progressive lenses. In comparison to other modalities of myopia control, atropine has a higher compliance and acceptance rate among parents, especially with younger children.

Super Sunday was a timely reminder of the importance of preserving a confluence between clinical and commercial practice

The landmark Atropine for the Treatment of Myopia (ATOM) studies show that atropine therapy creates a 50 per cent reduction in myopia progression. The ATOM 2 study confirmed that although there is a dose related effect, a 0.01 per cent atropine dosage is still effective, with lesser rebound effects and side effects compared to therapy at higher doses. These side effects include photophobia, impaired near focussing, and mydriasis. Some practitioners have identified that we have an ethical responsibility to prevent a child’s social, educational, and physical development from being compromised, particularly because children don’t always complain. This makes it important to consider prescribing the patient a near add, and transition lenses, even with the lower therapeutic dose.

Ms. Watt identified the importance of looking for key red flags for myopia progression during history and clinical testing when selecting suitable candidates. These include those of Asian ethnicity; with both parents myopic; who perform greater than 60 minutes of continuous close work regularly; who have less than 90 minutes of outdoor activity daily; and those with +0.50DS or less prescription at eight years (as the normal axial length growth is 0.05-0.1mm/year).

She suggested a work-up should include a thorough history (particularly determining existing allergies); visual acuity and cyclopleged refraction; accommodative function; pupil size and function; ocular health and measurement of intraocular pressures. Axial length is not completely necessary but can be obtained via co-management with University of New South Wales’ myopia clinic or a local ophthalmologist.

Therapy should be performed for two years, with review schedule at one week, three months, and six months. Ms. Watt recommended patients should be monitored closely, and re-treated if rebound myopia is observed.

It is important to cease atropine if there are any signs of reduced acuity due to retinal toxicity, allergic reaction and systemic side effects.

Window to the Soul

The cliché is that ‘the eyes are the window to the soul’, but a take home message of the day was that figuratively speaking, we should perceive the eyes as being the window to the brain. Embryologically, the eye develops as an outgrowth from the brain, and so it makes sense that anatomically the neurons, glia, and microvasculature all parallel that of the brain.

These physiological similarities, in hand with the non-invasive nature of optical coherence tomography, are putting eyes in the spotlight for monitoring of neurological disease. Optometrist David Foresto used Multiple Sclerosis (MS) as a case example. This progressive disease most commonly affects the brain, spinal cord, and optic nerves where demyelination causes sclerosis of axons. The link between MS and the eyes has long been known, with optic neuritis being the most common first sign of MS (present in 20 per cent of diagnoses). Forty per cent of patients who have a single episode of optic neuritis will go on to be diagnosed with MS within 10 years. In these cases, if anterior optic neuritis is involved, it is observable with optic disc swelling, and subsequent retinal nerve fibre layer (RNFL) thinning after an episode of optic neuritis is most prominent temporally.

Beyond this, the RNFL consists of unmyelinated axons from the ganglion cell layer, enabling us to directly measure the loss of axons from MS without extraneous variables such as loss of myelin mass. More than 50 per cent of retinal ganglion cell bodies are located in the macula. Inner retinal thinning in a macular scan correlates to function and can be mapped against field of vision. Contrastingly, RNFL analysis is centred on the optic disc, and so retinal nerve fibres from different parts of the visual field converge into one part of the disc. For example, temporal RNFL measurement contains the nasal part of visual field (RNF from the temporal retina), and temporal parts of the visual field (from the papillomacular bundle).

On this basis Dr. Simon Chen stressed the need to perform a baseline macula OCT, then screen routinely for retinal thickness changes. For example, Dr. Chen had a patient with an overall normal macular thickness, but with diffuse GCL thinning, indicating inner retinal atrophy. MRI was performed and multiple demyelinating lesions typical of MS were observed.

In a four year comparative study, OCT was deemed an easy, non-invasive tool for monitoring MS progression (correlating with measures of VA, contrast sensitivity, disability scores, and cerebral atrophy). Some studies even found measuring these changes helped predict MS relapses (patients who experienced this exhibited faster GCL thinning than those who did not experience a relapse).

The importance of doing these routine macular scans was stressed, and here is a useful clinical pearl Dr. Chen imparted: Thickening is caused by axonal edema, such as from acute optic neuritis, acute ischemia, and intracranial hypertension. Thinning is due to loss of GC axons, such as from neurodegenerative diseases, toxic/nutritional neuropathies, and following resolution of disc swelling.

We can expect to see more links between the eyes and neurodegenerative conditions discovered in the future. Links are currently being established with Alzheimer’s and Parkinson’s, and if they become validated by larger studies, we will find ourselves increasingly involved in neurology.

Ocular Nutrition

In a second presentation, David Foresto spoke about the role of ocular nutrition, which interestingly, ties in with neurodegenerative disease. MRI studies have established that increased vitamin D levels are associated with a reduced risk of developing MS (which could account for the incidence of MS increasing with further distance from the equator).

Vitamin D deficiency is estimated to affect 60 per cent of the world. Its active form (calictriol), formed as a reaction to UV-B radiation. Vitamin D facilitates calcium absorption and is considered to be a hormone in the sense that it is actively synthesised by the body and acts as an immunomodulator. This explains its lesser known role in reducing risk of autoimmune conditions such as type 1 diabetes, and colorectal cancer.

A study with controls, that compared people presenting with acute anterior uveitis, both from idiopathic and hla-b27 positive causes, found statistically significant lower levels of vitamin D in those with uveitis. Furthermore, mouse model studies have demonstrated that vitamin D can reverse uveitis by inhibiting uveal T-lymphocytes. Other studies have even found that vitamin D levels had an inverse association with early age related macular degeneration. Remembering to ask about blood work with patients of certain ocular presentations can help us better manage their risk of recurrence/progression, as well as their general health status.

Embracing Our Expanding Role

Overall, as optometrists, we need to be cognisant of our expanding roles as clinicians, even if we work in commercial practice. Optometry is not just about spectacle correction, rather, the eyes really can be used as a marker to help improve and understand/monitor general health status and quality of life.

In 2019 Super Sunday will take place at Luna Park on Sunday 10 March.

Layal Naji graduated as an optometrist from UNSW (2014) with her honours research project focusing on asylum seekers’ access to eye care in NSW. She currently divides her time between her locum work, the Asylum Seeker Centre in Newtown and UNSW where she is a clinical supervisor. Ms. Naji is passionate about optometry’s role in public health, and ocular manifestations of chronic lifestyle related disease.

Homma Ebrahimi graduated from Optometry at UNSW in 2014 and now works with Specsavers to deliver quality patient care in a busy practice environment. She is interested in improving access to eye care in the community, stemming from her honours research project and involvement with the Newtown Asylum Seeker Centre.