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Papers by robert devenyi

Objective: To evaluate if Photobiomodulation (PBM) can affect vision in patients with dry Age-Rel... more Objective: To evaluate if Photobiomodulation (PBM) can affect vision in patients with dry Age-Related Macular Degeneration (AMD). Methods: Prospective interventional case series. Near Infra Red (NIR) and yellow wavelengths of low powered light were applied to eyes with AMD in serial consecutive treatments. Included were patients with dry AMD, 50 years or older and with visual acuity between 20/20 20/200. Primary outcome measures selected were change in visual acuity, contrast sensitivity and fixation stability. Results: The treatment protocol was completed in 18 eyes (9 patients). Changes in visual acuity (p<0.0001) and contrast sensitivity (p<0.0001 at 3 cycles/degree and p<0.0032 at 1.5 cycles/degree) were positive and significant. There were no significant changes in fixation stability parameters.

Journal of Ophthalmology

Purpose. To present a series of retinal disease cases that were imaged by spectral domain optical... more Purpose. To present a series of retinal disease cases that were imaged by spectral domain optical coherence tomography (SD-OCT) in order to illustrate the potential and limitations of this new imaging modality. Methods. The series comprised four selected cases (one case each) of age-related macular degeneration (ARMD), diabetic retinopathy (DR), central retinal artery occlusion (CRAO), and branch retinal vein occlusion (BRVO). Patients were imaged using the Heidelberg Spectralis (Heidelberg Engineering, Germany) in SD-OCT mode. Patients also underwent digital fundus photography and clinical assessment. Results. SD-OCT imaging of a case of age-related macular degeneration revealed a subfoveal choroidal neovascular membrane with detachment of the retinal pigment epithelium (RPE) and neurosensory retina. Using SD-OCT, the cases of DR and BRVO both exhibited macular edema with cystoid spaces visible in the outer retina. Conclusions. The ability of SD-OCT to clearly and objectively eluci...

Canadian Journal of Ophthalmology

Surgical restoration of vision with retinal prostheses is a new and developing technology current... more Surgical restoration of vision with retinal prostheses is a new and developing technology currently available in a select group of countries, Canada among them. The Argus II retinal prosthesis is the first commercially available device for restoration of vision in patients with Retinitis Pigmentosa or with similar retinal pathology who still have minimal residual native vision. The surgery is complex and requires training however it is within the abilities of any experienced retina surgeon. Surgical experience builds up with each case and in our patients length of surgery constantly went down. Complications occurred however we experienced no catastrophic events. Most notable is that in our implanted cases the Argus II technology proved to be beneficial to most patients. In order to obtain optimal results with this surgical intervention it is absolutely required that the surgical work is complemented simultaneously with the work of a specialized rehabilitation team. A review of the technology, of our experience, comments and concerns is presented in this paper. Le rétablissement chirurgical de la vision à l'aide de prothèses rétiniennes est une nouvelle technologie en développement dans un petit nombre de pays, dont le Canada. La prothèse rétinienne Argus II est le premier dispositif commercial qui permette de restaurer une certaine vision chez les patients atteints de rétinite pigmentaire ou d'autres affections rétiniennes et qui disposent d'un minimum de vision résiduelle. L'intervention est complexe et demande de la formation, mais demeure à la portée de tout chirurgien rétinologue d'expérience. La dextérité chirurgicale s'accroît avec l'expérience et, chez nos patients, la durée de l'intervention a systématiquement diminué. Il s'est produit des complications, mais aucun incident catastrophique n'a été déploré. Fait le plus notable, la technologie de l'Argus II s'est révélée bénéfique chez la plupart de nos patients qui ont reçu l'implant. Pour s'assurer d'obtenir des résultats optimaux, il est vital que le travail du chirurgien soit épaulé par celui d'une équipe de réadaptation spécialisée.

British Journal of Ophthalmology

Ophthalmologica. Journal international d'ophtalmologie. International journal of ophthalmology. Zeitschrift fur Augenheilkunde, 2018

Canadian journal of ophthalmology. Journal canadien d'ophtalmologie, 2018

The Argus II retinal prosthesis is the first commercially available device for restoration of vis... more The Argus II retinal prosthesis is the first commercially available device for restoration of vision in patients with Retinitis Pigmentosa or with similar retinal pathology who still have minimal residual native vision. The technology is able to restore vision with production of artificial visual percepts which usually are given adequate useful interpretation by the visual system in most implanted patients. The technology usually produces visual perception at the level of shape identification or better in some cases enabling in many less dependence on vision substitution devices and skills. There is no consensus among vision rehabilitation practitioners on single methods for assessments, outcome measures and training, yet there is constant progress in these areas of concern. Hence the current vision rehabilitation practice related to the implantation of the Argus II retinal prosthesis is a work in progress with many learning opportunities for all involved. All agree that implementat...

Canadian Journal of Ophthalmology / Journal Canadien d'Ophtalmologie

To assess how polypoidal choroidal vasculopathy (PCV) is recognized and treated, and to assess wh... more To assess how polypoidal choroidal vasculopathy (PCV) is recognized and treated, and to assess whether treatment outcomes are different between Chinese and Caucasian Canadian patients with age-related macular degeneration (AMD). Retrospective chart review. 154 eyes from 135 Chinese patients and 2291 eyes from 1792 Caucasian patients who were newly diagnosed with either AMD or PCV and had more than 1 year of follow-up were included. All newly diagnosed AMD patients presenting to the Retina Service of 3 Toronto University Hospitals, between March 25, 2008, to September 30, 2014, were reviewed. 10/154 eyes (6.5%) in Chinese Canadians and 16/2291 eyes (0.7%) in Caucasian Canadians were diagnosed as having PCV. Indocyanine green angiography (ICGA) was used to diagnose PCV in 20% of Chinese Canadians and 8.8% of Caucasian Canadians. Clinical practices with a larger percentage of Chinese patients were more likely to diagnose PCV in both Chinese (p = 0.004) and Caucasian patients (p = 0.03), were more likely to use photodynamic therapy (PDT) (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01), and had significantly greater central retinal thickness decrease (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). Our study has shown that PCV is under-recognized in a Canadian population, and ICGA is underutilized. In clinical practices with a greater portion of Chinese patients, PCV is more often recognized and PDT is used more liberally.

Retina (Philadelphia, Pa.), Jan 23, 2017

To examine the relationship between retinal detachment and retrobulbar cysts in patients with opt... more To examine the relationship between retinal detachment and retrobulbar cysts in patients with optic nerve coloboma (ONC) and Morning Glory syndrome (MGS). Patients diagnosed with either ONC or MGS were identified through a search of the Sick Kids database. Seventy-one patients either agreed to come in for a B-scan or had an incidental orbital B-scan or magnetic resonance imaging or both. Eyes with orbital B-scan ultrasound and/or magnetic resonance imaging images were assessed independently by two ophthalmologists and a radiologist for the presence of retrobulbar cysts. Retinal detachment was identified clinically with either indirect ophthalmoscopy or from fundus photographs. Forty-five of 71 (63%) and 26/71 (37%) patients had ONC and MGS, respectively. Retinal detachment occurred significantly more often in eyes with MGS than with ONC (9/17 [53%] vs. 5/45 [11%], P = 0.03, respectively). Retrobulbar cysts were not detected more often in MGS than in ONC (11/45 [24%] vs. 7/26 [27%]; ...

Acta ophthalmologica, Jan 18, 2016

To evaluate the efficacy of photobiomodulation (PBM) treatment for patients with dry age-related ... more To evaluate the efficacy of photobiomodulation (PBM) treatment for patients with dry age-related macular degeneration (AMD). Assessments on 42 eyes with dry AMD (age related eye disease study (AREDS) 2-4) were conducted. Multiwavelength light emitting diode (LED) light comprising of yellow (590 nm), red (670 nm) and near-infrared (790 nm) bandwidths was applied to subjects' eyes for a treatment course of 3 weeks. Outcome measures were changes in best-corrected visual acuity (BCVA), contrast sensitivity (CS), drusen volume and central drusen thickness. Significant improvement in mean BCVA of 5.90 letters (p < 0.001) was seen on completion of the 3-week treatment and 5.14 letters (p < 0.001) after 3 months. Contrast sensitivity improved significantly (log unit improvement of 0.11 (p = 0.02) at 3 weeks and 3 months (log unit improvement of 0.16 (p = 0.02) at three cycles per degree. Drusen volume decreased by 0.024 mm(3) (p < 0.001) and central drusen thickness was signifi...

BMC ophthalmology, Jan 29, 2016

Ophthalmologica, 2016

To evaluate the pharmacogenetic relationship between CFH haplotypes and single nucleotide polymor... more To evaluate the pharmacogenetic relationship between CFH haplotypes and single nucleotide polymorphisms (SNPs) with response to ranibizumab treatment for neovascular age-related macular degeneration (nAMD). This was a prospective cohort study involving 70 treatment-naive nAMD patients. Patients were genotyped for CFH haplotypes and SNPs in the C3, ARMS2, and mtDNA genes. Visual acuity and central macular thickness were assessed at baseline and during 6 monthly follow-up visits. Multivariate logistic regression was used to determine the association between genotypes and a gain of ≥15 letters at the 6-month endpoint after adjusting for potential confounders. CFH haplotypes were associated with a gain of ≥15 letters at the 6-month endpoint (p = 0.046). Patients expressing protective haplotypes were more likely to achieve a gain of ≥15 letters relative to the greatly increased risk haplotypes [OR 6.58 (95% CI: 1.37, 31.59)]. CFH is implicated in nAMD patient treatment response to ranibizumab.

Can J Ophthalmol J Can Ophtal, 2006

Canadian journal of ophthalmology. Journal canadien d'ophtalmologie, 2016

BMC ophthalmology, Jan 6, 2016

A position paper based on the collective experiences of Argus II Retinal Prosthesis System invest... more A position paper based on the collective experiences of Argus II Retinal Prosthesis System investigators to review strategies to optimize outcomes in patients with retinitis pigmentosa undergoing retinal prosthesis implantation. Retinal surgeons, device programmers, and rehabilitation specialists from Europe, Canada, Middle East, and the United States were convened to the first international Argus II Investigator Meeting held in Ann Arbor, MI in March 2015. The recommendations from the collective experiences were collected. Factors associated with successful outcomes were determined. Factors leading to successful outcomes begin with appropriate patient selection, expectation counseling, and preoperative retinal assessment. Challenges to surgical implantation include presence of staphyloma and inadequate Tenon's capsule or conjunctiva. Modified surgical technique may reduce risks of complications such as hypotony and conjunctival erosion. Rehabilitation efforts and correlation wi...

Retina (Philadelphia, Pa.), Jan 12, 2015

A review of treat-and-extend regimens (TERs) with intravitreal anti-vascular endothelial growth f... more A review of treat-and-extend regimens (TERs) with intravitreal anti-vascular endothelial growth factor agents in retinal diseases. There is a lack of consensus on the definition and optimal application of TER in clinical practice. This article describes the supporting evidence and subsequent development of a generic algorithm for TER dosing with anti-vascular endothelial growth factor agents, considering factors such as criteria for extension. A TER algorithm was developed; TER is defined as an individualized proactive dosing regimen usually initiated by monthly injections until a maximal clinical response is observed (frequently determined by optical coherence tomography), followed by increasing intervals between injections (and evaluations) depending on disease activity. The TER regimen has emerged as an effective approach to tailoring the dosing regimen and for reducing treatment burden (visits and injections) compared with fixed monthly dosing or monthly visits with optical cohe...

The British journal of ophthalmology, 2014

To evaluate the effect of scleral buckling on intraocular pressure (IOP) change during atmospheri... more To evaluate the effect of scleral buckling on intraocular pressure (IOP) change during atmospheric decompression for eyes with small volumes of intravitreal gas. 12 eyes of 12 patients, including 6 with and 6 without scleral buckles, were evaluated in a hypobaric chamber simulating air travel approximately 1 month post pars plana vitrectomy with 15% C3F8 gas fluid exchange. The chamber was decompressed with an ascent rate of 300 feet/min to a peak altitude of 8000 feet. After 15 min of cruising, descent was undertaken at 300 feet/min. IOP was measured at baseline and then every 5 min using slit-lamp mounted Goldmann applanation tonometry. The data were entered onto a spreadsheet and comparative statistics were done. During ascent, IOP steadily rose from an average of 13±3 mm Hg to a peak of 26±9 mm Hg at 8000 feet. Patients with scleral buckles had significantly lower peak IOPs compared with those without buckles (20±5 mm Hg vs 32±8 mm Hg, p=0.013, t test) representing lower absolut...