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Report

ODMA CPD returns to Sydney

05/09/2017
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ODMA17’s highly anticipated return to Sydney’s revamped International Convention Centre featured an all-day Vision Summit presented by some of ophthalmology’s foremost experts. LEWIS WILLIAMS was there to document the highlights in a two part special report.

ODMA17’s Vision Summit was presented by a high-profile assembly of academic clinicians, who delivered a package that mirrored their extensive knowledge and experience. All were local except for US-based ophthalmologist Dr Rolando Toyos, the pioneer of using intense pulsed light (IPL) for the treatment of dry eye and MGD.

Local speakers were; Professor Minas Coroneo, chairman of UNSW’s Department of Ophthalmology; Professor Fiona Stapleton, Head of UNSW’s School of Optometry and Vision Science; Director of the Save Sight Institute (SSI) and Professor of Clinical Ophthalmology and Eye Health Peter McCluskey; and Associate Professor Gerald Liew, a medical retina ophthalmologist who holds an academic position at the Westmead Hospital complex and also works in private practice in Sydney’s suburbs.

KEYNOTE SPEAKERS

Fiona Stapleton

Gerald Liew

Minas Coroneo

Stephanie Watson

Non-refractive laser treatments

In ophthalmology, laser technology is now being used for diagnostic, cosmetic, and therapeutic purposes. Coroneo began exploring this topic by describing how the application of laser energy can be used successfully on pingueculae and conjunctival naevi, despite it being ineffective for the treatment of pterygium. However, he explained how laser tools could be used to create tissue for a conjunctival autograft to be used in post-pterygium-surgery ocular surface reconstruction. An argon-ion 514.5 nm laser is the tool of choice.

Raising the subject of eye tattooing, Coroneo warned not only of the possibility of perforating eye injuries, but also of problems further down the track should any ocular laser procedure be required. Medical professionals have been known to use a platinum chloride/hydrazine corneal tattoo to hide a corneal scar or to create an artificial corneal aperture in the case of anirida, however, the problem is that artists are responsible for the majority eye tattoos, which are for cosmetic purposes only.

Although worse with black pigment, any such material in the eye also increases local energy absorption that can either thwart the intentions of a specialist or induce unwanted side effects. In addition, lid tattoos have been shown to decrease meibomian gland function.

Advantages of laser technology, usually YAG, can be found in intracorneal biofilm disruption (in the immuno-suppressed), recurrent corneal erosions (RCEs), lash removal, and of all things, shed tarantula ‘hairs’. The latter’s thin and pointed nature has resulted in the ‘hairs’, which could be more accurately described as barbs, being found at the level of the retina if left in situ long enough. Their slightly pigmented nature is sufficient to allow laser obliteration while they are still located in the cornea.

Coroneo explained that RCEs can be treated by stromal puncture, laser, or pharmacologically. Unless dry eye disease is present, the latter treatment now achieves up to a 90% success rate, while Cyclosporine has also successfully treated RCE cases.

While the removal of unwanted or errant eyelashes can be achieved with a laser, radio frequency (RF) radiation has a greater success rate of 82% compared with the 63% of cases treated with a laser. Meanwhile, to reduce the loss of tear fluid from the eye, alternatives such as punctal plugs (complete stoppage) or laser narrowing of the puncta (reduced drainage) can also be employed.

Coroneo described how a medical CO2 laser could be employed to treat ectropion by using the ensuing tissue shrinkage to reposition the lid against the globe. Similarly, laser ‘welding’ can also be used to perform sutureless cataract surgery and to close penetrating keratoplasty (PK) wounds.

The indocyanine green (ICG) chromophore used with a laser diode (solid-state laser) plays a role in ocular angiography, although much of that role is now being overtaken by recent developments in OCTA. YAG lasers are used to make indelible reference marks in the cornea to assist in toric IOL orientation during implantation.

The plumes of ablated ocular tissue resulting from laser application, although previously thought of as insignificant and probably harmless, have taken on new significance with the realisation that prions and HPV, as well as some other viruses, can survive laser ablation and be spread in the plumes. The American Society of Cataract and Refractive Surgeons now mandates plume extraction as part of best practice.

Moving to the topic of pterygium surgery, Coroneo defined the aim of surgical intervention as ‘the restoration of the ocular surface’, rather than the removal of unwanted and problematic additional ocular tissue. A good outcome needs consideration of the anatomical, functional, cosmetic, and symptom alleviation along with a desire to have zero refractive effect as well as no recurrence. He believes we are close to realising a zero recurrence rate and noted that early intervention is desirable.

Despite being regarded widely as something of a ‘Cinderella disease’ in ophthalmology, Coroneo stated categorically that pterygium is not a trivial disease. Interestingly, he also advised that no surgery be performed in summer, as there is an increased risk of a corneo-scleral melt.

Clinical trials are difficult as there is no known animal model and the first surgery is usually the best chance of solving the problem. Pterygium can be considered an ocular surface malignancy and can be accompanied by a decreased endothelial cell count. Sufferers are more prone to cataracts, and skin and eyelid malignancies, while they have a 2–3x greater risk of AMD. Those most prone to the problem are surfers and arc welders, but there is genetic predisposition as well. The wearing of sunglasses was encouraged, while monitoring is usually done by serial photographs and serial imaging of anterior eye UV fluorescence.

Not all cases require surgery, although there is gap between the early stage, which has few unwanted effects, and the more serious late stage of the disease, where regular and irregular refractive effects are common, in which a patient might seek surgery for non-compelling reasons.

A conjunctival autograft, first suggested in 1931 but only rediscovered in the 1980s, is still regarded as the gold standard of treatment.

Big grafts, as performed by Brisbane’s Professor Laurie Hirst and Coroneo, are preferred, but require special attention paid to preserving the limbal stem cells maximally. Importantly, all excised tissue should be sent to pathology because it is now known that up to 12% of cases have atypical cells warranting further investigation.

Hirst’s recurrence rate has been estimated at 0.4%. That low rate is attributed to the removal of large areas of Tenon’s capsule, believed to be the source of recurrence. The once popular use of amniotic membranes rather than an autograft has declined in the light of more recent developments, while the use of the potent DNA cross-linker mitomycin-C has also dropped to a low level.

Factors affecting recurrence adversely include: dry eye, leaving Tenon’s largely unaltered, limbus issues, previous eye surgery, a surgeon factor, UV exposure, and surgery being performed in summer. A steroid is also needed to reduce recurrence, but the IOP must be monitored to assess any steroid-induced elevation.

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The use of an anti-inflammatory and an anti-VEGF drug such as Avastin might also be beneficial to the long-term outcome, as might the use of cyclosporine – especially on the bare sclera. However, that combination can result in up to 2 D of induced astigmatism. At the 5-year reassessment mark, some 78% of post-surgical cases still had abnormal Schirmer Tear Test results.

Coroneo also warned that caution was needed when dealing with AMD patients on anti-VEGF therapy, as lingering anti-VEGF can affect surgery.

From a vision standpoint, surgery reduces higher order aberrations (HOAs), but changes in refraction and vision quality can be expected for at least the first year post-surgically. No refractive surgery should be contemplated within that time or until vision is relatively stable.

When imaged using OCT, even small pterygia can be seen to have deep roots into the anterior eye. A recent technique, femtosecond laser-assisted pterygium surgery (FLAPS), involves ablating about 77 microns of tissue. An assessment of excised tissue by a pathologist is important because of the risk that an ocular surface squamous neoplasia (OSSN) might be involved. That risk is greatest in elderly males with fair skin that have been exposed to the sun excessively.

OSSNs tend to recur, require destructive surgery, and tend to recur in different locations subsequently, to the extent that the surgeon ends up playing ‘wack-a-mole’ with each new recurrence. Another option that, after 12 months of treatment, is about 98% successful and generates minimal side effects, harnesses the synergy between retinoic acid and interferon (RAIN). The HPV virus has also been implicated in the aetiology of OSSN. For those cases resisting the foregoing, the anti-tumour drug cidofovir is used.

Management and imaging of uveitis

Professor Peter McCluskey began his presentation by noting that problems affecting the uvea often ‘spilled over’ into other ocular structures, despite the fact that it involved just the choroid, the ciliary body and processes, and the iris. With a prevalence of just 0.03%, it still rates as the 22nd most common human disease. Those figures translate into 10,000–20,000 cases a year in Australia, although its local epidemiology is still not well understood.

Peter McCluskey
Peter McCluskey

While only about 40% of cases experience some reduction in VA, uveitis is the third most common cause of blindness, leading McCluskey to describe it as a ‘bad’ disease. He then detailed the SUN Classification of the disease (Standardisation of Uveitis Nomenclature Working Group): Anterior, Intermediate, Posterior, and Panuveitis.

McCluskey estimates there are at least 27 phenotypes of inflammatory and infectious uveitis, and said that males represent 59% of cases. The mean age of those affected is about 27 years, but the range is broad at 16–93 years. Anterior uveitis is the most common form and accounts for up to 64% of cases, followed by intermediate uveitis, 9%, and posterior/panuveitis which combine to represent up to 28%.

Half of all cases are classified as idiopathic, 30% are inflammatory, and 20% are infective in origin. Determining the cause of a uveitic episode requires a careful history that sometimes involves digging deeply (as not all relevant information is volunteered necessarily) a comprehensive internal and external ocular examination, and review of all ocular systems.

Other relevant aspects warranting consideration include: any syndromes that might be present, any differential diagnoses that need to be made through selective investigations, determining the cause of any vision loss reported, and the formulation of a treatment plan.

Up to 90% of anterior uveitis cases involve both the iris and the ciliary body, recur – often episodically – and result in flare and fibrin in the anterior chamber causing an hypopyon. This can be highly suggestive of an association with HLA-B27 – which occurs in about 50% of cases – Behçet’s disease, or, less commonly, an infection. However, the condition tends to be self-limiting and the prognosis is usually good, especially if the number of episodes is not great.

Chronic anterior uveitis has a poorer prognosis and usually greater vision loss. As an umbrella statement, McCluskey warned that syphilis, which is becoming increasingly prevalent in our society again, could mimic any phenotype of uveitis. Anterior uveitis is often found to have ankylosing spondylitis associated with it and a dilated fundus examination (DFE) is essential for seeking cells and the resulting flare, especially in the anterior chamber.

McCluskey also mentioned Arlt’s triangle, a base-down triangle whose apex is at or below the corneal apex, in which cells and debris (keratic precipitates) are deposited on the corneal endothelium in active intraocular diseases. Iris pigment epithelium loss, best seen in fundal retro-illumination, is a hallmark of herpetic uveitis and as a result, pupil reactions can also be affected.

While 50% of acute anterior uveitis (AAV) might be HLA-B27-related, only some 1–2% of those who are HLA-B27 positive develop the disease. Intermediate uveitis, which is found in the peripheral retina, pars plana, and the vitreous, is idiopathic in 69% of cases. It is associated with sarcoidosis in 22% of cases, with the remaining 1% due to MS and Lyme disease, making it important to also ask about tick bites.

Uveitis technically refers to inflammation in a layer of the eye
Uveitis technically refers to inflammation in a layer of the eye

Posterior and panuveitis are less common. Signs of vasculitis, inflammation, or retinal spots and scars should be sought. The venous system is more likely to be involved that the arterial system, however, the latter is more likely in cases of lupus, Behçet’s, and toxoplasmosis. If both the arteries and veins are affected then acute retinal necrosis (ARN), Behçet’s disease, and toxoplasmosis are more likely to be present. Retinitis, which is mostly infective in aetiology, should not be confused with panuveitis. Suggested imaging methods include: Optos wide-field imaging, autofluorescence, OCTA, or OCT.

In Australia, about 5% of panuveitis cases are syphilitic in origin and are curable using anti-inflammatory and anti-infective therapy, such as corticosteroids or immunomodulatory therapy (IMT) drugs. However, steroids have side effects such as weight gain, increased risk of glaucoma, etc. McCluskey referred to an IMT and biologics (monoclonal antibodies) revolution happening that began in 2016/2017. The use of adalimumab, a TNF-inhibiting, anti-inflammatory biologic can help get patients off steroids. Sometimes local and systemic therapies are required and it is usually beneficial to have the patient’s rheumatologist in the treatment loop.

In his uveitis-imaging lecture, McCluskey included B-Scan ultrasound as well as more recent developments such as OCT and OCTA. Although TB is uncommon in Australia, the level of migration in recent years of people from TB-afflicted countries means that local practitioners can no longer ignore the possibility of occlusive retinal vasculitis.

Treatment than can span 6–9 months might include corticosteroids with or without methotrexate. Regardless, ocular TB is still relatively uncommon in Australia although it remains a notifiable disease and its incidence has increased significantly in the last 10 years. It has been shown to remain latent in the RPE.

Punctate inner choroidopathy (PIC) is a condition requiring 3–6 injections of an anti-VEGF, in which haemorrhaging is a sign of local ischaemia. With the prevalence of syphilis in VIC, NSW, and especially the NT reaching public health problem levels, syphilitic posterior placoid chorioretinopathy is increasingly common. The frequent pairing of syphilis and HIV has meant a disproportionate increase in related problems.

More reading: Special Report Part 2: ODMAs CPD return to Sydney mostly welcomed

 

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