Laser treatment for early stage macular degeneration, ocular surface reconstruction surgery using limbal stem cells, and strategies to minimise risks in practice… these were just some of the topics presented as part of a strong educational program at WAVE 2013 in Western Australia.
Among a high profile line up of speakers at WAVE was Dr. Lauren Ayton, Bionic Eye Clinical Research Coordinator with the Centre for Eye Research Australia, Dr. Andrea Ang, a Consultant Ophthalmologist from the Lions Eye Institute and Royal Perth Hospital and Jared Slater, National Professional Services Manager at Optometrists Association Australia.
In one of three presentations, Dr. Lauren Ayton called on fellow optometrists to refer patients for a clinical trial into a treatment that could one day eliminate macular degeneration in its earliest stages.
“At the moment there are anti-VEGF treatments for end-stage age-related macular degeneration (AMD) – what we’re looking at is a potential new treatment for people with the earliest signs of disease. These patients have high risk macular drusen, but they haven’t yet lost their vision or developed any signs of late stage damage,” said Dr. Ayton.
With… understanding of the roles of limbal stem cells, we can now visually rehabilitate these patients that would otherwise be blind
She said the Laser Intervention in Early Age-Related Macular Degeneration (LEAD) Study, being led by Professor Robyn Guymer and using the novel low-energy nanosecond 2RT laser, is looking at people with the highest risk of developing vision loss – those with intermediate AMD signs (drusen > 125µm and/or pigment).
“Laser is applied at the edges of the retina near the blood vessel arcades, and has been shown to cause drusen resolution and improved retinal function,” said Dr. Ayton.
She said the treatment objective is to trigger a wound healing response in the retinal pigment epithelium (RPE), without damaging the neuro-retina at all.
“This is hypothesised to result in an improvement in the hydraulic conductivity of Bruch’s membrane, resulting in improved retinal function and thereby delaying the more serious complications of late stage AMD,” said Dr. Ayton.
In a pilot study conducted from 2010 – 2012, 50 participants with bilateral high risk intermediate AMD (drusen >125µm +/- pigment) were treated with 12 x 2RT laser spots near the arcades (1000µm from fovea).
“Excitingly, in approximately 25 per cent of the eyes, the bilateral untreated eye also showed improvements in drusen reduction and retinal function,” she said.
Clinical trials of the 2RT laser treatment are underway at the Centre for Eye Research Australia in Melbourne, the Lions Eye Institute in Perth and Marsden Eye Specialists in Sydney. The CERA team is hoping to undertake more trials overseas, possibly in Oxford, Belfast and Utah.
Dr. Ayton said more candidates are required for the trial. “We’re looking for people aged 50-95 years with intermediate AMD – that is they have best corrected visual acuity of 6/12 or better OU, with bilateral drusen of greater than 125um in both eyes, with or without pigment”.
She said the candidates for the LEAD clinical trial are optometric patients. “This is an exciting project for optometrists to become involved in, as we are the primary eye health practitioner that many people with early AMD consult.”
If you are interested in referring patients for this study, please contact Kate Brassington at the Centre for Eye Research Australia; firstname.lastname@example.org
Ocular Surface Reconstruction
In a well-received presentation, Dr. Andrea Ang, a Consultant Ophthalmologist from the Lions Eye Institute and Royal Perth Hospital, discussed the treatment algorithm in ocular surface reconstruction surgery.
Patients with severe ocular surface disease are some of the most difficult, challenging, and yet rewarding patients to manage. Diseases such as chemical burns, Stevens-Johnson syndrome, ocular cicatricial pemphigoid, and aniridia, can cause permanent scarring of the cornea by damaging the limbal stem cells.
Limbal stem cell deficiency (LSCD) leads to persistent epithelial defects, corneal ulceration and scarring, and conjunctivalisation of the cornea, rendering the patient blind and/or in chronic pain.
“Traditionally patients with a failed ocular surface had multiple corneal transplants that subsequently failed, and there were no other treatment options”, said Dr. Ang. “However, there are now new options available: limbal stem cell transplantation and keratoprostheses (artificial corneas).”
Dr. Ang, who has recently returned to Perth from two corneal fellowships at the Cincinnati Eye Institute and the Singapore National Eye Centre, discussed the pros and cons of each approach. “For a patient with truly unilateral disease, such as a chemical injury, then a conjunctival autograft with limbal stem cells from the healthy fellow eye is the treatment of choice. The major advantage is there is no chance of rejecting your own stem cells.
“Unfortunately, many diseases are bilateral, so the fellow eye can’t be used, and the stem cells need to come from a donor, either a cadaver-donor or a living relative.”
Dr. Ang explained that similar to kidney transplants, these patients require oral immunosuppression to prevent immune rejection of the limbal stem cells. “Systemic immunosuppression however is relatively safe in this healthy group of patients, compared to unwell renal transplant patients.”
Dr. Ang discussed the option of using an artificial cornea, including the Boston Type 1 KPro, which is the most widely used KPro in the world. “The major advantage of using an artificial cornea is that it is a one-stage procedure and no immunosuppression is required.”
However, she cautioned the used of the KPro and said patient selection, long-term follow-up and monitoring for complications is crucial for success. “Patients are immensely happy and can even see 6/6 vision week one after surgery. However, these devices should not be used lightly in a patient, as long-term studies have found glaucoma to be a major cause of loss of vision. With a plastic optic, it is impossible to assess the intraocular pressure, and as we know, digital palpation is a rather crude substitute.”
Dr. Ang also cautioned the use in patients with conjunctival inflammation such as in chemical injuries, where there is a high chance of melting and extrusion of the device.
She concluded that both stem cells and KPros have a role in ocular surface reconstruction. “With improved surgical techniques and understanding of the roles of limbal stem cells, we can now visually rehabilitate these patients that would otherwise be blind”.
Legal and Ethical Responsibilities
On a more practice based note, Jared Slater, National Professional Services manager at Optometrists Association Australia spoke to delegates about the legal and ethical responsibilities of health care practitioners when providing care.
Mr. Slater reminded his audience that eye care professionals have a duty of care to not cause harm and to inform patients of risk. He spoke on codes of conduct, clinical guidelines and issues surrounding informed consent.
Mr. Slater reviewed the type of eye conditions that have high medico-legal risk for optometrists and spoke in-depth on risk management.
He said it is important to record details of each patient’s history and investigations performed, including negative as well as positive findings
“To mitigate risk, it is important to educate and inform patients about their condition, treatment plan and options, and to ensure the patient knows what to do if their condition does not improve or deteriorates. You need to do this by providing clear instructions on next steps,” said Mr. Slater. “You must document your instructions to the patient on the patient record, including recommendations for referral and review.
“Ensure the patient understands the management plan, including any referral and the reason for it, and check your patient records at every visit to ensure continuity of care.”
Mr. Slater said it is important to include the patient’s GP in referrals and that when referring a patient on, “transfer of care to another health professional can lead to assumptions and oversights regarding provision of ongoing care and advice – so it is necessary to be aware of the risks involved with this”.
In concluding, Mr. Slater said a proper recall system will also help to mitigate risk.
Tony Martella, CEO of Optometrists Association Australia’s WA division, said the conference program, which was worth up to 43 CPD points, was complemented by a solid exhibition from 30 leading optical suppliers and a highly enjoyable cocktail event that allowed the 170 delegates in attendance to relax and mingle with colleagues. “We are extremely pleased from both a delegate and an exhibitor perspective,” he said of the two-day event, held at Perth’s Pan Pacific Hotel.
In 2013 WAVE will take place from 15–17 August 2014.