Dr. Amir Norouzpour is an Academic-Staff Research Scientist at Byers Eye Institute at Stanford University. His primary research interests are neural correlates of attention and visual perception. He works on an analytical method to estimate the intra-individual variability of steady-state visual evoked potentials as a potential objective index of individual ability to control visual attention. He is involved in research programs studying concussion-related vision disorders and vision development using visual evoked potentials in the Vision Development and Oculomotor lab directed by Dr. Tawna Roberts.
Current Role at Stanford
Education & Certifications
Post-doctoral scholar, University of California at Berkeley, Visual Neuroscience (2017)
Residency of Ophthalmology, Mashhad University of Medical Sciences, Iran, Ophthalmology (2015)
MD, Mashhad University of Medical Sciences, Iran, Medicine (2010)
Binocular vision development
Professional Affiliations and Activities
Director of Visual Neuroscience lab, Shiraz University of Medical Sciences, Iran (2021 - 2022)
Assistant Professor of Ophthalmology, Shiraz University of Medical Sciences, Iran (2020 - 2021)
Assistant Professor of Ophthalmology, Birjand University of Medical Sciences, Iran (2017 - 2019)
A complementary note for the analytical method to estimate individual attention fluctuation using steady-state evoked potentials
Biomedical Signal Processing and Control
View details for DOI 10.1016/j.bspc.2022.104406
Long-term Visual and Refractive Outcomes of Argon Laser-treated Retinopathy of Prematurity.
Journal of ophthalmic & vision research
2022; 17 (3): 384-389
In this case-control study, we measured visual acuity, objective refraction, ocular biometric parameters, and strabismus in premature cases classified according to the following categories: argon laser-treated retinopathy of prematurity (ROP), untreated spontaneously regressed ROP, no ROP, and full-term controls.Cases with a history of prematurity at six years of age were categorized into the following groups: patients with a history of treated type 1 ROP using argon laser (group I), untreated spontaneously regressed ROP (group II), and no history of ROP (group III). Group IV included age-matched healthy full-term controls. Funduscopy was performed for all the cases and the control group.In total, 24 eyes of 12 laser-treated ROP cases, 186 eyes of 93 spontaneously regressed ROP patients, 74 eyes of 37 premature cases with no history of ROP, and 286 eyes of 143 controls were included in the study. The mean spherical equivalent in the treated cases was not significantly different from that in the untreated cases and patients in group III. However, the average cylindrical power was significantly different among the groups (P < 0.004). Furthermore, anisometropia ( ≥ 1.5 diopters) was diagnosed with a higher rate in the treated cases (P = 0.03). The corneal curvature of the laser-treated eyes was significantly steeper and the axial length was significantly shorter than those in the other groups (P < 0.002 and P < 0.001, respectively, for multivariate analysis). Strabismus was found in three treated patients (25%). Additionally, there were three treated eyes (12.5%) diagnosed with macular dragging.Premature cases including those who had a history of argon laser-treated ROP and those with untreated spontaneously regressed ROP showed acceptable long-term visual and refractive outcomes along with a fairly low rate of ocular disorders.
View details for DOI 10.18502/jovr.v17i3.11576
View details for PubMedID 36160100
View details for PubMedCentralID PMC9493422
A novel analytical method to measure intra-individual variability of steady-state evoked potentials; new insights into attention deficit
BIOMEDICAL SIGNAL PROCESSING AND CONTROL
View details for DOI 10.1016/j.bspc.2021.103109
View details for Web of Science ID 000713282900005
Central corneal thickness measurements in phakic, pseudophakic, and aphakic children with ultrasound pachymetry and different non-contact devices
2022; 42 (1): 65-72
Evidence for choosing a satisfactory device for central corneal thickness (CCT) measurement in children particularly pseudophakic and aphakic ones is insufficient. The aim of this study is to compare four differently measured CCTs obtained using ultrasound pachymetry (UP), Pentacam, partial coherence interferometry (PCI), and specular microscopy (SM) in phakic, pseudophakic, and aphakic children and assess the agreement between the six pairs of the methods.Children with history of cataract surgery at age six or younger and phakic children were recruited into this study. CCT was measured using UP (Optikon 2000, Rome, Italy), Pentacam (Oculus Inc, Wetzlar, Germany), PCI (IOLMaster 700, Carl Zeiss Meditec AG, Jena, Germany), and SM (Topcon SP-3000P; Topcon Corporation, Japan).One-hundred two eyes (53 phakic, 29 pseudophakic, and 20 aphakic eyes) were included. The mean ages (± SD) of phakic, pseudophakic, and aphakic cases were 9.75 (± 3.3), 9.9 (± 2.3), and 8.2 (± 2.8) years, respectively. The mean CCTs (± SE) for phakic children using Pentacam, PCI, UP, and SM were 549.7 (± 5.0), 546.5 (± 4.5), 565.9 (± 5.5), and 506.2 (± 4.4) μm, respectively, for pseudophakic cases were 570.1 (± 6.4), 565.0 (± 6.1), 571.9 (± 6.3), and 524.3 (± 6.3) μm, respectively, and for aphakic participants were 635.3 (± 14.2), 635.4 (± 14.5), 649.0 (± 13.5), and 589.1 (± 13.3) μm, respectively.Compared to Pentacam and PCI, SM underestimated CCT particularly in phakic and pseudophakic children, whereas UP slightly overestimated CCT especially in phakic and aphakic children. Furthermore, Pentacam and PCI had the closest agreement. By contrast, SM had the poorest agreement with the other three methods.
View details for DOI 10.1007/s10792-021-02000-y
View details for Web of Science ID 000683304000004
View details for PubMedID 34370171
Light exposure in acute central serous chorioretinopathy
2022; 36 (1): 243
View details for DOI 10.1038/s41433-020-01388-8
View details for Web of Science ID 000606372900001
View details for PubMedID 33423042
View details for PubMedCentralID PMC8727572
Glaucomatous Optic Neuropathy: Associated With Cognitive Impairment?
JOURNAL OF GLAUCOMA
2021; 30 (1): E21
View details for DOI 10.1097/IJG.0000000000001668
View details for Web of Science ID 000610964500010
View details for PubMedID 32925519
Birjand longitudinal aging study (BLAS): the objectives, study protocol and design (wave I: baseline data gathering)
JOURNAL OF DIABETES AND METABOLIC DISORDERS
2020; 19 (1): 551-559
The pace of population aging is growing rapidly around the world. Aging is associated with the emergence of different health status including geriatric syndrome such as frailty, diabetes, cardiovascular diseases, and dementia. These conditions are the most prominent challenges for health care systems and also elderly people. Therefore, understanding these changes can help scientists to prevent and treat significant health issues and also improve the functional ability of older adults.This is a protocol of the first wave of Birjand Longitudinal Aging Study that is an ongoing community-based prospective cohort study with a following up at least 10 years. This study carries out on aged population ≥ 60 years which were residents in Birjand County (urban and rural older subjects). The selection of the participants of this study in urban areas is based on an age group weighted multistage stratified random sample while in the rural region the sample was selected from all ten rural regions of Birjand County by simple random sampling. The rural region sampling was based on the list of the aged population which were under the coverage of the rural health center. Sociodemographic, past medical history, lifestyle, sleep, activities of daily living, cognitive function, quality of life, and social capital were evaluated by interviewing with the participants and one of the informants. Anthropometric measures, electrocardiography, and interpretation of ophthalmologic examination were carried out by experts. Fasting Blood samples were collected and bio-banked in - 80 °C. then finally biochemical and hematologic markers were measured.This is the protocol of stage one baseline of Birjand Longitudinal Aging Study (BLAS). The BLAS is an enjoining study, the first phase of its baseline was carried out on a community- dwelling aged population sample ≥ 60 years who were residents in urban and rural regions of Birjand County. This is a community based prospective cohort study with at least 10 years follow up of participants. The data for 65% of older subjects (response rate = 65%) that lived in clusters were collected.This study can help scientists to recognize some risk factors related to the aging process and also aware policymakers about the necessity to create heath care services at regional and even national levels.
View details for DOI 10.1007/s40200-020-00504-5
View details for Web of Science ID 000571450700062
View details for PubMedID 32550207
View details for PubMedCentralID PMC7271344
Coronavirus disease 2019: Global Contamination and Global Cleanup
GALEN MEDICAL JOURNAL
2020; 9: e1921
View details for DOI 10.31661/gmj.v9i0.1921
View details for Web of Science ID 000569900400001
View details for PubMedID 34466613
View details for PubMedCentralID PMC8344154
Tuberculosis: A Cunning Disease Presenting with Endopericarditis-Associated Bilateral Uveitis
TURK OFTALMOLOJI DERGISI-TURKISH JOURNAL OF OPHTHALMOLOGY
2019; 49 (6): 361-363
Mycobacterium tuberculosis can spread through the entire body but rarely involves the eye. We report a patient with endophthalmitis in one eye and simultaneous retinal vasculitis in the fellow eye. Systemic work-up suggested infective endopericarditis. Polymerase chain reaction analyses of the vitreous and pericardial fluid were positive for M. tuberculosis. We initiated a four-drug antituberculous treatment regimen (isoniazid, ethambutol, pyrazinamide, and rifampin). After two weeks, we discontinued all the medications due to drug-induced hepatitis. We restarted isoniazid and rifampin, but hepatitis recurred. Finally, we chose isoniazid/ethambutol combination for 18 months, and also administered short-term systemic corticosteroid. His vision improved considerably with no recurrence of hepatitis or tuberculosis for 3 years after completion of treatment. Ocular tuberculosis can masquerade as other causes of intraocular inflammation, and a medical team consisting of an ophthalmologist and an infectious disease specialist might be needed for the diagnosis and management.
View details for DOI 10.4274/tjo.galenos.2019.55889
View details for Web of Science ID 000505067800010
View details for PubMedID 31893593
View details for PubMedCentralID PMC6961073
Hydrophilic Acrylic Intraocular Lens Opacification after Descemet Stripping Automated Endothelial Keratoplasty.
Journal of ophthalmic & vision research
2016; 11 (2): 225-7
To report hydrophilic acylic intraocular lens (IOL) opacification after Descemet Stripping Automated Endothelial Keratoplasty (DSAEK) in an eye with multiple prior intraocular surgeries and iatrogenic aniridia.A 34-year-old woman with history of penetrating keratoplasty (PKP) for advanced keratoconus and subsequent Urrets-Zavalia Syndrome (UZS) underwent phacoemulsification and hydrophilic acrylic IOL implantation for her cataract. In order to control post-PKP glaucoma, multiple glaucoma surgeries including two glaucoma drainage implants were performed. As the original corneal graft failed, the patient subsequently underwent re-PKP. Four years later, she underwent DSAEK for treatment of the second graft failure. Ten months after DSAEK, a double semi-circular pattern of IOL opacification was observed on the anterior surface of the IOL. The patient did not report any complaints and we decided not to exchange the IOL.In an eye with UZS and iatrogenic aniridia, IOL opacification may result from direct contact between the IOL surface and exogenous air. Aniridia can be a risk factor for development of IOL opacification after DSAEK. Further studies are required to confirm this hypothesis.
View details for DOI 10.4103/2008-322X.158897
View details for PubMedID 27413506
View details for PubMedCentralID PMC4926573
Central serous chorioretinopathy: from glucocorticoids to light intensity
INTERNATIONAL JOURNAL OF OPHTHALMOLOGY
2016; 9 (2): 312-314
Central serous chorioretinopathy (CSC) is characterized by a localized accumulation of subretinal fluid and an idiopathic focal leakage from choroidal vessels. The exact pathogenesis of CSC, however, still remains obscure. In this paper, we hypothesized that CSC may result from a response of choroidal vessels to an acute increase in the environmental light intensity leading to a focal leakage from the choroidal vessels. High levels of glucocorticoids, in our proposed model, may cause persistence rather than initiation of the focal leakage, probably by suppressing the synthesis of collagen and extracellular matrix components and inhibiting fibroblastic activity.
View details for Web of Science ID 000369551700025
View details for PubMedID 26949657
View details for PubMedCentralID PMC4761749
Treatment of Chronic Central Serous Chorioretinopathy with Oral Methotrexate
JOURNAL OF OCULAR PHARMACOLOGY AND THERAPEUTICS
2015; 31 (8): 468-475
To evaluate the effects of oral methotrexate (MTX) in patients with chronic central serous chorioretinopathy (CSC).This is an interventional, prospective uncontrolled clinical trial, which included 23 eyes of 23 consecutive patients presenting with chronic symptomatic CSC and persistent subretinal fluid (SRF) for longer than 3 months. All patients were treated with 7.5 mg/week of oral MTX for 12 weeks. The best corrected visual acuity (BCVA), central macular thickness (CMT), SRF, and total macular volume recorded by monthly optical coherence tomography were analyzed. Complete blood count and serum liver enzymes level were monitored.Mean duration of CSC was 13 months (3-36 months). Mean BCVA improved from 20/40 at baseline to 20/30 at the third month and 20/28 at the sixth month (P=0.002 and 0.003, respectively). Mean CMT decreased from 375 μm at baseline to 278 μm and 265 μm at the third and sixth month (P=0.002 and 0.007, respectively). Mean total macular volume decreased from 9.33 mm(3) at baseline to 8.48 and 8.31 mm(3) at the third and sixth month (P=0.001 and 0.001, respectively). Thirteen (62%) eyes achieved complete resolution of SRF. No MTX-associated toxicity was detected.Low-dose oral MTX may be an alternative therapeutic option for the treatment of chronic CSC. This study paves the way for a randomized clinical trial comparing the effects of MTX treatment with photodynamic therapy or observation.
View details for DOI 10.1089/jop.2014.0173
View details for Web of Science ID 000362270600005
View details for PubMedID 26172430
Retinal vascular fractals in Behcet's Disease: A screening method?
SAUDI JOURNAL OF OPHTHALMOLOGY
2015; 29 (3): 210-211
The branching pattern of retinal vessels may be affected in Behçet's Disease (BD). Fractal analysis can be used as a new method to quantify the changes of the vascular branching pattern. In this study, we examined, for the first time, the relationship between retinal fractal dimension (D f) and retinal vascular changes seen in patients with BD.We conducted a retrospective study of 10 new cases of BD with clinically ocular involvement. Color fundus images taken from both eyes of the participants have been analyzed, and D f of the whole retinal vasculature was quantified using a novel computer-based program. The resultant D f was compared with that of healthy individuals.The mean D f, calculated from 20 fundus images of cases with BD, was 1.59 ± 0.064. It was lower than that of healthy participants (1.65 ± 0.060) significantly (P = 0.013).Retinal fractal analysis of cases with BD has been performed for the first time, and the results showed that early retinal vascular changes seen in new cases of BD are associated with lower retinal D f. Retinal fractal analysis in BD can be practically utilized as a potential tool for screening of retinal involvement, evaluating the prognosis and the response to treatment.
View details for DOI 10.1016/j.sjopt.2015.01.003
View details for Web of Science ID 000217146200008
View details for PubMedID 26155081
View details for PubMedCentralID PMC4487937
Central serous chorioretinopathy and bright light
2014; 92 (8): e688-e689
View details for DOI 10.1111/aos.12484
View details for Web of Science ID 000345342600017
View details for PubMedID 25042604
New insights into blindness; mechanical fatigue of optic nerve head in glaucomatous optic neuropathy.
Journal of medical engineering & technology
2014; 38 (7): 367-71
A common cause of blindness worldwide is glaucoma. It is characterized by visual field loss which is caused by optic nerve damage leading to glaucomatous optic neuropathy (GON). Modelling of GON development may be helpful for designing strategies to decelerate the rate of GON progression and prevent GON development at early stages. Attempts to complete the modelling of GON development continue. In this paper, it was speculated that the modelling could be more completed through a biomechanical point of view. GON may result from the mechanical fatigue effects of radial tensile stress (TS), caused by intra-ocular pressure (IOP), on the optic nerve head (ONH). The mechanical fatigue rate is influenced by patient's age, the maximum and minimum magnitude of IOP, the amplitude of IOP and TS fluctuations, the ONH geometry, scleral thickness and biomechanical properties of the sclera, particularly the peripapillary part, and the axial length of the globe. Based on this model, more efficient strategies can be developed to augment the ONH and decelerate the progression of glaucomatous optic nerve damage, and even screen high-risk individuals at early stages.
View details for DOI 10.3109/03091902.2014.950435
View details for PubMedID 25188359
Letter to the Editor: Bright Light Induces Choroidal Thickening in Chickens
OPTOMETRY AND VISION SCIENCE
2014; 91 (4): E94
View details for DOI 10.1097/OPX.0000000000000207
View details for Web of Science ID 000333756600001
View details for PubMedID 24561963
Prehospital Management of Gunshot Patients at Major Trauma Care Centers: Exploring the Gaps in Patient Care
2013; 18 (2): 62-66
Prehospital management of gunshot-wounded (GW) patients influences injury-induced morbidity and mortality.To evaluate prehospital management to GW patients emphasizing the protocol of patient transfer to appropriate centers.This prospective study, included all GW patients referred to four major, level-I hospitals in Mashhad, Iran. We evaluated demographic data, triage, transport vehicles of patients, hospitalization time and the outcome.There were 66 GW patients. The most affected body parts were extremities (60.6%, n = 40); 59% of cases (n = 39) were transferred to the hospitals with vehicles other than an ambulance. Furthermore, 77.3% of patients came to the hospitals directly from the site of event, and 22.7% of patients were referred from other medical centers. EMS action intervals from dispatchers to scene departure was not significantly different from established standards; however, arrival to hospital took longer than optimal standards. Additionally, time spent at emergency wards to stabilize vital signs was significantly less in patients who were transported by EMS ambulances (P = 0.01), but not with private ambulances (P = 0.47). However, ambulance pre-hospital care was not associated with a shorter hospital stay. Injury Severity was the only determinant of hospital stay duration (β = 0.36, P = 0.01) in multivariate analysis.GW was more frequent in extremities and the most patients were directly transferred from the accident site. EMS (but not private) ambulance transport improved patients' emergency care and standard time intervals were achieved by EMS; however more than a half of the cases were transferred by vehicles other than an ambulance. Nevertheless, ambulance transportation (either by EMS or by private ambulance) was not associated with a shorter hospital stay. This showed that upgrade of ambulance equipment and training of private ambulance personnel may be needed.
View details for DOI 10.5812/traumamon.10438
View details for Web of Science ID 000218902400006
View details for PubMedID 24350154
View details for PubMedCentralID PMC3860682
Autoregulation of blood flow: Vessel diameter changes in response to different temperatures.
Journal of biomedical physics & engineering
2013; 3 (2): 63-6
Autoregulation of blood flow is a marvelous phenomenon balancing blood supply and tissue demand. Although many chemically-based explanations for this phenomenon have been proposed and some of them are commonly used today, biomechanical aspects of this phenomenon was neglected. The biomechanical aspect provides insights to us to model vessel diameter changes more precisely and comprehensively. One important aspect of autoregulation phenomenon is temperature changes of the tissue resulted from tissue metabolism. We hypothesize that temperature changes can affect the mechanical properties of the vessel wall leading to vessel diameter changes during autoregulation. Mechanical modeling of vessel diameter changes can also be useful to explain other phenomena in which the vessel diameter changes in response to temperature alterations. Through the mechanical modeling of any vessel, the analysis of temperature-induced changes in vessel diameter can be done more precisely.
View details for PubMedID 25505749
View details for PubMedCentralID PMC4204495
A novel insight into keratoconus: mechanical fatigue of the cornea.
Medical hypothesis, discovery & innovation ophthalmology journal
2012; 1 (1): 14-7
An integrated model for keratectasia risk assessment has received much attention over many years. The objective of this article is to propose a more complete, conceptual model by which high risk individuals can be screened, even with no topographic irregularity or corneal thinning. In this model, corneal ectasia results from the fatigue effect of cyclic shear stress and tensile stress, caused by eye rubbing and fluctuating intraocular pressure (IOP), respectively, on corneal microstructures. The model clarifies the importance of the magnitude of shearing force applied by eye rubbing, the amplitude of IOP fluctuations, the frequency of eye rubbing and IOP fluctuations, the geometry of the cornea, the temperature of the cornea, and the effects of oxidative stress on the cornea in keratectasia development. Therefore, preoperative screening strategies based on these concepts can be designed to assess the risk of keratectasia at an early stage, and select the best candidates who can benefit from keratorefractive surgeries.
View details for PubMedID 24600612
View details for PubMedCentralID PMC3939737
Designing strategies to control coronary atherosclerosis using a new model
INTERNATIONAL JOURNAL OF CARDIOLOGY
2010; 143 (3): 440-441
View details for DOI 10.1016/j.ijcard.2008.12.004
View details for Web of Science ID 000281874500038
View details for PubMedID 19117627
New insights in atherosclerosis: Endothelial shear stress as promoter rather than initiator
2009; 73 (6): 989-993
The etiology of focal distribution of atherosclerotic lesions has received much attention for many years. Current theories focus on mechanical factors such as low endothelial shear stress as an initiating factor for atherosclerosis formation. However, some evidences revealed that it could not be initiator of endothelial damage. We hypothesize that endothelial damage results from the fatigue effect of pulse pressure on endothelial layer. In our model, heart rate, magnitude of pulse pressure, geometry and chemical environment of endothelial layer determine the rate of endothelial damage accumulation, and low endothelial shear stress acts as promoter of atherosclerosis rather than initiator. If this model is correct, it can provide a framework for speculating about the risk of endothelial stress rupture in the population as a whole and in patients undergone arterial grafting procedures, and how this might be reduced.
View details for DOI 10.1016/j.mehy.2008.11.049
View details for Web of Science ID 000272923000030
View details for PubMedID 19577380