David I. T. Sia
University of Adelaide
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Publication
Featured researches published by David I. T. Sia.
Ophthalmic Epidemiology | 2010
David I. T. Sia; James Muecke; Michael Hammerton; Meng Ngy; Aimee Kong; Anna Morse; Martin Holmes; Horm Piseth; Carolyn Hamilton; Dinesh Selva
Purpose: To identify the causes of blindness and severe visual impairment (BL/SVI) in children attending four schools for the blind in Cambodia and to provide spectacles, low vision aids, orientation and mobility training and ophthalmic treatment. Methods: Children < 16 years of age were recruited from all 4 schools for the blind in Cambodia. Causes of visual impairment and blindness were determined and categorized using World Health Organization methods. Results: Of the 95 children examined, 54.7% were blind (BL) and 10.5% were severely visually impaired (SVI). The major anatomical site of BL/SVI was the lens in 27.4%, cornea in 25.8%, retina in 21% and whole globe in 17.7%. The major underlying etiologies of BL/SVI were hereditary factors (mainly cataract and retinal dystrophies) in 45.2%, undetermined/unknown (mainly microphthalmia and anterior segment dysgenesis) in 38.7% and childhood factors in 11.3%. Avoidable causes of BL/SVI accounted for 50% of the cases; 12.9% of the total were preventable with measles being the commonest cause (8.1% of the total); 37.1% were treatable with cataracts and glaucoma being the commonest causes (22.6% and 4.8% respectively). More than 35% of children required an optical device and 27.4% had potential for visual improvement with intervention. Conclusion: Half of the BL/SVI causes were potentially avoidable. The data support the need for increased coverage of measles immunization. There is also a need to develop specialized pediatric ophthalmic services for the management of surgically remediable conditions, to provide optometric, low vision and orientation and mobility services. Genetic risk counseling services also may be considered.
Acta Ophthalmologica | 2013
David I. T. Sia; Sean Martin; Gary A. Wittert; Robert J. Casson
Purpose: To describe the age‐related change in contrast sensitivity seen in 35‐ to 80‐year‐old men in an Australian population.
Ophthalmic Epidemiology | 2010
David I. T. Sia; Kapila Edussuriya; Saman Sennanayake; Tissa Senaratne; Dinesh Selva; Robert J. Casson
Purpose: To report the prevalence and risk factors associated with primary open-angle glaucoma (POAG) in the Kandy district of central Sri Lanka. Methods: A cross-sectional, population-based ophthalmic survey of the inhabitants ≥ 40 years of age from villages in the Kandy District, Sri Lanka was conducted. Selection was randomized using a cluster sampling process; 1721 eligible participants were identified, 1375 participated in the study and sufficient examination data to diagnose glaucoma in at least one eye was obtained in 1244 participants. A detailed ophthalmic history and examination including ocular biometry was made of each participant. Primary open-angle glaucoma was classified into three levels according to diagnostic evidence. Results: The overall prevalence of POAG was 2.3% (95% CI 1.5–3.2). In the univariate analyses, increasing age (P = 0.001), intraocular pressure (IOP) (P < 0.001), myopia (P < 0.001) and axial length (P = 0.003) were significantly associated with POAG. In the multivariate analysis, age (P = 0.001), mean IOP (P < 0.001) and mean axial length (P = 0.008) were significant risk factors of POAG. Conclusions: The prevalence of POAG in the population aged ≥40 years in central Sri Lanka was 2.3%. POAG in this population was independently associated with increasing age, IOP and axial length.
Ophthalmic Plastic and Reconstructive Surgery | 2011
Wencan Wu; David I. T. Sia; Paul S. Cannon; Dinesh Selva; Yunhai Tu; Jia Qu
A 59-year-old Chinese man presented with no light perception in the left eye 1 day following functional endoscopic sinus surgery. The patient underwent endoscopic optic nerve decompression with topical and systemic application of nerve growth factor and steroids after a failed trial of high-dose intravenous corticosteroids. Visual acuity improved to 20/25 at 3 weeks and remained stable at 9 months. Reports of full visual recovery are exceedingly rare following this functional endoscopic sinus surgery complication.
Clinical and Experimental Ophthalmology | 2013
James Muecke; David I. T. Sia; Henry S Newland; Robert J. Casson; Dinesh Selva
There are over 300 million people living in the world today who are visually impaired and a further 45 million who are blind. The large majority (90%) of these people live in developing countries, and up to 75% of blindness are avoidable. With cataracts being the major cause of blindness and visual impairment, many ophthalmic aid programmes are aimed at alleviating the enormous burden caused by this readily treatable disease. Having said that, caution should be exercised that short surgical visits to remote rural areas that are not coordinated with local national eye care managers should be discouraged because they do little for the development of sustainable eye care programmes. With this in view, it has become imperative to design blindness prevention and ophthalmic support programmes that are workable, comprehensive, economical and sustainable.There are over 300 million people living in the world today who are visually impaired and a further 45 million who are blind. The large majority (90%) of these people live in developing countries, and up to 75% of blindness are avoidable. With cataracts being the major cause of blindness and visual impairment, many ophthalmic aid programmes are aimed at alleviating the enormous burden caused by this readily treatable disease. Having said that, caution should be exercised that short surgical visits to remote rural areas that are not coordinated with local national eye care managers should be discouraged because they do little for the development of sustainable eye care programmes. With this in view, it has become imperative to design blindness prevention and ophthalmic support programmes that are workable, comprehensive, economical and sustainable.
Orbit | 2012
David I. T. Sia; Weng Onn Chan; Peter J. Wormald; Garry Davis; Dinesh Selva
The use of endoscopic orbital and optic nerve decompression for traumatic optic neuropathy and dysthyroid orbitopathy have been well documented; however, reports on endoscopic decompression for benign orbital apex lesions are scarce. The records of two patients who underwent endoscopic decompression of the bony orbit for progressive visual loss were reviewed. Patient 1 had fibrous dysplasia and presented with headache and visual field defects. Patient 2 had sphenoid wing meningioma and multiple previous attempts of transcranial tumor resection and orbital decompression. Both had progressive visual deterioration and ultimately underwent transnasal endoscopic orbital decompression. Post-operatively, both patients had subjective and objective improvement in visual function and compressive symptoms. No complications from the endoscopic decompression were observed in both patients. Transnasal endoscopic approach may be a viable option for decompression of benign orbital apex lesions.
Orbit | 2012
David I. T. Sia; Garry Davis; Dinesh Selva
Orbitofrontal cholesterol granuloma is a rare entity that has a predilection for men in their fourth or fifth decade and occurs almost exclusively within the frontal bone overlying the lacrimal fossa. Surgery by drainage and curettage is virtually curative in all cases and recurrence is very rare. We describe the case of a 77-year-old man with recurrent orbitofrontal cholesterol granuloma 11 years after surgery, presumably due to subtotal curettage. The potential use of an endoscope to aid complete removal of lesion is discussed.
Clinical and Experimental Ophthalmology | 2010
David I. T. Sia; Paul S. Cannon; Dinesh Selva
An 80-year-old man presented with an 8-week history of painless swelling in the right lacrimal gland region with infero-medial dystopia of the globe. The lesion was excised and histology confirmed an orbital plasmacytoma. Multiple myeloma screening was negative and a solitary extramedullary plasmacytoma arising from the lacrimal gland was diagnosed. The patient was subsequently treated with radiotherapy.An 80‐year‐old man presented with an 8‐week history of painless swelling in the right lacrimal gland region with infero‐medial dystopia of the globe. The lesion was excised and histology confirmed an orbital plasmacytoma. Multiple myeloma screening was negative and a solitary extramedullary plasmacytoma arising from the lacrimal gland was diagnosed. The patient was subsequently treated with radiotherapy.
Journal of Neuro-ophthalmology | 2015
Paul Ikgan Sia; David I. T. Sia; John Crompton; Robert J. Casson
Thiamine deficiency classically manifests as the triad of Wernicke encephalopathy: acute confusional state, ataxic gait, and ocular motor dysfunction. However, most patients do no present with this classic triad. Optic neuropathy in thiamine deficiency is a rare manifestation and is usually associated with fundus appearances of optic disc swelling or optic disc pallor. We present 2 unique cases of thiamine deficiency where the fundus demonstrated peripapillary retinal nerve fiber layer thickening without florid disc swelling or pallor.
Clinical and Experimental Ophthalmology | 2012
James Muecke; David I. T. Sia; Henry S Newland; Robert J. Casson; Dinesh Selva
There are over 300 million people living in the world today who are visually impaired and a further 45 million who are blind. The large majority (90%) of these people live in developing countries, and up to 75% of blindness are avoidable. With cataracts being the major cause of blindness and visual impairment, many ophthalmic aid programmes are aimed at alleviating the enormous burden caused by this readily treatable disease. Having said that, caution should be exercised that short surgical visits to remote rural areas that are not coordinated with local national eye care managers should be discouraged because they do little for the development of sustainable eye care programmes. With this in view, it has become imperative to design blindness prevention and ophthalmic support programmes that are workable, comprehensive, economical and sustainable.There are over 300 million people living in the world today who are visually impaired and a further 45 million who are blind. The large majority (90%) of these people live in developing countries, and up to 75% of blindness are avoidable. With cataracts being the major cause of blindness and visual impairment, many ophthalmic aid programmes are aimed at alleviating the enormous burden caused by this readily treatable disease. Having said that, caution should be exercised that short surgical visits to remote rural areas that are not coordinated with local national eye care managers should be discouraged because they do little for the development of sustainable eye care programmes. With this in view, it has become imperative to design blindness prevention and ophthalmic support programmes that are workable, comprehensive, economical and sustainable.