For more information, visit:

Visual Electrophysiology Unit

Brief Biography

Dr. Carol Westall obtained her PhD from the University of California (Berkeley) in 1984. She is a registered clinical optometrist and Director of the Visual Electrophysiology Unit at SickKids. Under her direction, the Visual Electrophysiology Unit has become a world leader in clinical paediatric visual electrophysiology. Westall is member of the Board of the International Society for Clinical Visual Electrophysiology and Vision and is on the editorial board of the Society’s journal (Documenta Ophthalmologica). Westall's research investigates neuro-visual markers of visual dysfunction when the developing visual system has been compromised. In 2009 Westall took on the role of Graduate Coordinator at the University of Toronto, Institute of Medical Science.

Clinical Care Activities

Provides leadership to the Visual Electrophysiology Unit (VEU) through technical expertise and academic advancement in paediatric visual electrophysiology and vision function assessment. Supports research and translates new knowledge to clinical procedures.

Research Interests

• Neuro-Visual Development
• Electroretinography
• Visual Toxicity
• Markers of visual dysfunction in diabetes

Research Activities

We are conducting investigations into neurovisual markers of visual dysfunction when the developing visual system has been compromised. My lab develops neurovisual tests to assess abnormalities in the developing visual system - from retina to higher cortical areas - with the aim of establishing a centre for investigations of neurovisual pathway functions from "bench to bedside".

Currently, my lab is investigating neurovisual dysfunction in children with early diabetes and in children with infantile spasms who are taking an antiepileptic drug (vigabatrin). Vigabatrin is known to cause retinal toxicity in about 30% of patients. The aim of the studies is detection of early markers of disease, the early detection of which would be the first step toward disease intervention.

Our results from noninvasive vision function testing show that the neural tissue within the retina and the visual pathways of the brain may be subject to damage as a result of diabetes. We aim to identify which neurovisual markers precede detectable vascular dysfunction in type 1 diabetes and which markers of neuronal disease are predictive of subsequent sight-threatening diabetic retinopathy. Currently this is a major drive of our lab and will be accelerated further with the onset of structural imaging made possible with equipment funds from the Canadian Foundation for Innovation.

Future Research Interests

I plan to expand on the development of neuro-ocular tests to assess abnormalities at any stage in the developing visual system; from retina to higher cortical areas. Our team aims to establish a centre for investigations of neuro-visual pathway functions from “bench to bedside”.

Current funding will allow us to pursue studies of neuro-visual dysfunction in children with early diabetes and in children with infantile spasms taking the antiepileptic drug vigabatrin. Our aims are to detect early markers of later disease, the detection of which would be the first step to disease intervention.

External Funding

2010-2015. CIHR project grant 
Structural and functional markers of neuro-retinal complications in adolescents with early type 1 diabetes. PI: Westall, Co-inv: Campbell.

2010-2015. CIHR project grant
Donor Human Milk Versus Preterm Formula as a Substitute for Mothers' Own Milk for Feeding Very Low Birth Weight Infants. PI: O'Connor, Co-inv: Asztalos, Kiss, Rovet, Westall.

2010-2012. CHRP
Localizing Light in the Eye for Diagnostic and Therapeutic Applications. PI: Campbell M. Co Inv: Boyd S, Bizheva K, Sanderson, Strickland D, Westall C.

2007-2011. Canada Foundation for Innovation
Centre for the Investigation of Neuroplasticity and Developmental Disorders. PI: Snead III OC. Co Inv: Taylor M, Campbell M, Cheyne D, Dennis M, Josselyn S, Salter M, Sled J, Tannock R, Westall CA.

2009-2012. Lunbeck Pharmaceuticals inc.
Markers of neuro-retinal change over time in children with infantile spasms. PI: Westall CA.

Achievements

• May 2010 - Fellow ARVO (FARVO), The Association for Research in Vision and Ophthalmology. (Distinction) In honor of outstanding service to the eye and vision community.
• September 2007. Member at Large, International Society for Clinical Electrophysiology of Vision.
• 2007. Vice Chair, Optical Society of America Fall Vision Meeting, clinical section.
• December 2006. American Academy of Optometry. Chair of the Vision Sciences Section, Diplomat committee.
• April 2004. Mel Silverman Mentorship Award, The Institute of Medical Science, University of Toronto.
• December 2004. American Academy of Optometry, Elected Vice Chair of the Vision Sciences Section, Diplomat committee.
• December 2003. Diplomate in Vision Sciences (visual electrophysiology), The American Academy of Optometry.
• November 2002. EDITORIAL BOARD: Documenta Ophthalmologica.

Publications

McFarlane M, Wright T, Stephens D, Westall C. S-cone ERG PhNR changes associated with poor long-term glycemic control in adolescents with type 1 diabetes. Investigative Ophthalmology and Visual Science (Published online before print January 4, 2012, doi: 10.1167/iovs.11-8263).

Sergott RC, Westall CA. Primer on visual field testing, electroretinography, and other visual assessments for patients treated with vigabatrin. (2011). Acta Neurologica Scandinavic, 124, (SUPPL. 192), 48-56.

Vincent A, Wright T, Day MA, Westall CA, Heon, E. (2011). A novel p.Gly603Arg mutation in CACNA1F causes Al and island eye disease and incomplete congenital stationary night blindness phenotypes in a family.  Mol Vis 17: 3262-3270.

Lakhani E. (2010) Insufficient long-term glycaemia control is associated with multifocal ERG defects in adolescents with type 1 diabetes.  Invest Ophthalmol Vis Sci. 2010 Oct;51(10):5297-303.

Wygnanski-Jaffe T, Panton CM, Buncic JR, Westall CA. (2009) Robust visual evoked potentials in young patients with cortical blindness. Documenta Ophthalmologica 1119(2): 01-7.

Durban S, Mirabella G, Buncic JR, Westall CA. (2009)  Reduced grating acuity associated with retinal toxicity in children with infantile spasms on vigabatrin therapy. Invest Ophthalmol Vis Sci.  50(8): 4011-6

Nilsson J, Wright T, Westall C. (2008) Rod photoreceptor function in a clinical population referred for ERG: bright flash rod response adds information on rod system function. Vision Research 48(18): 1920-5.

Wright T, Nilsson J, Gerth C, Westall C. (2008). A comparison of signal detection techniques in the multifocal electroretinogram. Doc Ophthalmol. 117(2): 163-70.

Gerth CG, Mirabella G, Li X, Wright T, Westall CA, Colpa L, Wong A. (2008). Timing of surgery for infantile esotropia in humans: effects on cortical motion visual evoked responses. Invest Ophthalmol Vis Sci. (49) (08): 3432-7

Mirabella G, Morong S, Buncic JR, Snead OC, Logan WJ, Weiss SK, Westall CA. (2007) Contrast sensitivity is reduced in children with childhood epilepsy. Investigative Ophthalmology & Vis Sci. 48 (08): 3610-5.

Chang BCM, Mirabella G, Yagev R, Banh M, Mezer E, Parkin PC, Westall CA, Buncic JR. (2007) Screening and diagnosis of optic pathway gliomas in children with neurofibromatosis type 1 using sweep visual evoked potentials. Investigative Ophthalmology & Vis Sci. 48 (06): 2895-902.

Gerth C, Wright T, Heon E, Westall CA. (2007) Assessment of central retinal function in patients with advanced retinitis pigmentosa. Invest Ophthalmol Vis Sci 48(03): 1312-8

Mirabella G, Morong S, Buncic JR, Snead OC, Logan WJ, Weiss SK, Westall CA. (2007) Contrast sensitivity is reduced in children with childhood epilepsy. Investigative Ophthalmology & Vis Sci. 48 (08): 3610-5.

Gerth C, Wright T, Heon E, Westall CA. (2007) Assessment of central retinal function in patients with advanced retinitis pigmentosa. Invest Ophthalmol Vis Sci 48(03): 1312-8

Chang BC, Mirabella G, Yagev R, Banh M, Mezer E, Parkin PC, Westall CA, Buncic JR. (2007). Screening and diagnosis of optic pathway gliomas in children with neurofibromatosis type 1 by using sweep visual evoked potentials. Invest Ophthalmol Vis Sci, 48 (6), 2895-2902.

Elia YT, Daneman D, Rovet J, Abdolell M, Lam WC, Till C, Erraguntla V, Rubab S, Lodha N, Westall CA. (2005). Color visual evoked potentials in children with type 1 diabetes: relationship to metabolic control. Invest Ophthalmol Vis Sci, 46 (11), 4107-4113.

Till C, Westall CA, Koren G, Nulman I, Rovet JF. (2005). Vision abnormalities in young children exposed prenatally to organic solvents. Neurotoxicology, Aug;26(4):599-613.

Fulton AB, Brecelj J, Lorenz B, Moskowitz A, Thompson D, Westall CA. (2006). Pediatric clinical visual electrophysiology: a survey of actual practice. Doc Ophthalmol 113(3): 193-204.

Elia YT, Daneman D, Rovet J, Abdolell M, Lam WC, Till C, Erraguntla V, Rubab S, Lodha N, Westall CA. (2005). Color visual evoked potentials in children with type 1 diabetes: relationship to metabolic control. Invest Ophthalmol Vis Sci 46(11): 4107-13.

Westall CA. (2005). Detecting ocular-visual function changes in diabetes. Br J Ophthalmol 89(11): 1392-3.

Buncic JR, Westall CA, Panton CM, Munn JR, MacKeen LD, Logan WJ. (2004). Characteristic retinal atrophy with secondary "inverse" optic atrophy identifies vigabatrin toxicity in children. Ophthalmology, 111 (10), 1935-1942.

Westall CA, Eizenman M, Kraft SP, Panton CM, Chatterjee S, Sigesmund, D. (1998). Cortical binocularity and monocular optokinetic asymmetry in early-onset esotropia. Invest Ophthalmol Vis Sci, 39 (8), 1352-1360.

Intellectual Property

CRACK ERG: Software package to derive normal ranges of ERG results based on age. Licensed to SickKids