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Your providers


Stephanie Callisto



Dr David Sia



A/Prof Weng Onn Chan




Weng is a Consultant Ophthalmologist and Vitreoretinal Surgeon who returned to Adelaide in 2018 after completing his surgical retinal fellowship at the prestigious Moorfields Eye Hospital, London.
Weng attended medical school at the University of Otago, New Zealand, graduating in 2008 and winning the undergraduate John Parr Prize of Ophthalmology. After completing his ophthalmology training in South Austalia, he underwent further subspecialist training completing medical and surgical retinal fellowships at the Royal Adelaide Hospital, Adelaide and Vitreoretinal fellowship at Moorfields Eye Hospital, London.
Weng has been actively involved in both clinical and basic science research since 2008. He currently has more than 30 publications in international, peer reviewed ophthalmic journals and has also co-authored several book chapters. He has won numerous research grants and awards and has completed a Masters of Philosophy (Ophthalmology) and a Postgraduate Diploma in Ophthalmic Basic Sciences. Weng is heavily involved in teaching and has won several awards in recognition of his commitment to teaching.
Weng grew up in multiracial Malaysia and is fluent in English, Malay, Mandarin, Cantonese and Hokkien. Weng is also a keen learner of languages and speaks conversational Japanese.



Dr David Sia returned in 2020 with dual-fellowship training in Vitreoretinal Surgery and Ocular Oncology.
David obtained his medical degree from the University of Otago, New Zealand in 2009 and went on to undertake ophthalmology registrar training in Adelaide, South Australia and Alice Springs, Northern Territory.
Following completion of registrar training, David then pursued overseas fellowship training and completed a 13-month Ocular Oncology Fellowship in London, UK at the prestigious Moorfields Eye Hospital, St Bartholomew’s Hospital and Royal London Hospital. This was followed by a 2-year Vitreoretinal Fellowship in Edmonton, Canada, at Alberta Retina Consultants. During his fellowships, he gained extensive experience in treating medical and surgical retinal diseases, as well as adult and paediatric intraocular and ocular surface tumours. 
Upon returning to Adelaide, David was appointed as a Vitreoretinal Specialist and Ocular Oncologist at the Royal Adelaide Hospital, Flinders Medical Centre and Women’s and Children’s Hospital where he will be regularly involved in the training of future ophthalmologists and vitreoretinal surgeons. He is actively engaged in clinical research, has published widely and written book chapters. He currently holds a position as Clinical Associate Lecturer at the University of Adelaide.
In his free time, he enjoys photography, travel, reading, seeking out good food and working on computers. Having grown up in a multi-cultural background, he is fluent in English, Malay, Mandarin, Foochow. 
David is a dedicated professional who loves his craft. He is committed to providing the best care possible for his patients and loves to connect with them.



Stephanie is a therapeutically endorsed clinical optometrist providing shared care across all practice locations. She graduated from Flinders University with a Bachelor of Medical Science (Vision Science)/Master of Optometry in 2018 having completed part of her training in many regional communities in Australia and internationally. After completing her degree, she moved to Port Augusta to work in an independent optometry practice providing culturally safe primary ocular care to almost the entire northern region of South Australia. She gained extensive experience in diagnosing and managing a wide range of eye diseases while working closely with local health care providers and visiting ophthalmologists.


Stephanie works closely alongside ophthalmologists both in pre and post-operative care as well as assisting in the shared care of chronic eye conditions including glaucoma, cataracts, macular degeneration and diabetic retinopathy. She is a keen and passionate learner and has expanded her knowledge in retinal diseases and ocular oncology to ensure patients have access to timely care and support throughout their treatments. 

Shaping optometry’s future is a key passion of Stephanie’s. She does this by dividing her time between supervising and lecturing at Flinders University, sharing her passion and knowledge of ocular diseases and inspiring optometry students. As well as bringing her experience to a political level as a director on the board of Optometry Victoria/South Australia. 


Outside of work, Stephanie can be found spending time at the park with her fiancé and fur baby or ready to set off on her next adventure.

P: (08) 8267 1700

F: (08) 8239 1550

Opening Hours

Monday          9am - 5pm

Tuesday          9am - 5pm

Wednesday    9am - 5pm

Thursday        9am - 5pm

Friday             9am - 5pm

Saturday         Emergencies Only

Sunday           Emergencies Only

79 Pennington Terrace, North Adelaide 5006

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