Muhammad Hassan

Dr. Muhammad Hassan


Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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3 November 2015 in Journal of Ophthalmic Inflammation and Infection
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Journal Article
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MSMohammad Ali Sadiq
Mohammad Ali Sadiq
MHMuhammad Hassan
Muhammad Hassan
AAAniruddha Agarwal
Aniruddha Agarwal
SSSalman Sarwar
Salman Sarwar
STShafak Toufeeq
Shafak Toufeeq
QNQuan Dong Nguyen
Quan Dong Nguyen
Endogenous endophthalmitis is an ophthalmic emergency that can have severe sight-threatening complications. It is often a diagnostic challenge because it can manifest at any age and is associated with a number of underlying predisposing factors. Microorganisms associated with this condition vary along a broad spectrum. Depending upon the severity of the disease, both medical and surgical interventions may be employed. Due to rarity of the disease, there are no guidelines in literature for optimal management of these patients. In this review, treatment guidelines based on clinical data and microorganism profile have been proposed.

10 October 2018 in International Journal of Retina and Vitreous
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SSSalman Sarwar
Salman Sarwar
MHMuhammad Hassan
Muhammad Hassan
MSMohamed K. Soliman
Mohamed K. Soliman
MHMuhammad Sohail Halim
Muhammad Sohail Halim
MSMohammad Ali Sadiq
Mohammad Ali Sadiq
YSYasir J. Sepah
Yasir J. Sepah
Vessel flow density (VFD) may provide important information regarding perfusion status. Diurnal variation in VFD of choriocapillaris has not been reported in literature. In the index study, optical coherence tomography angiography (OCTA) was used to assess the diurnal variation of the VFD in the choriocapillaris of subjects with no known ocular disease. Fifty eyes with no known ocular disease (25 subjects) were included. OCTA images were acquired using AngioVue (Optovue, Fremont, CA, USA) at two different time points on a single day: 9:00 AM and 6:00 PM. Macular cube scan protocol (3 × 3 mm) centered on the fovea was used. Automatic segmentation of the retinal layers and choriocapillaris was performed using ReVue software, which was also used to measure the choriocapillaris VFD. Horizontal line scan passing through fovea was obtained by the device at both time points to measure the subfoveal choroidal thickness (CT). Linear measurement tool of software was used to measure subfoveal CT according to a standardized reproducible method. Wilcoxon signed-rank test was used to assess the differences in choriocapillaris VFD and subfoveal CT at the two time points. Correlation between change in choriocapillaris VFD and subfoveal CT at the two time points was assessed using the Pearson correlation coefficient (r). The mean age of the subjects was 31.96 ± 11.23 years. Choriocapillaris VFD was significantly higher at 9:00 AM compared to 6:00 PM (P < 0.0001) with mean choriocapillaris VFD of 68.74 ± 4.80% at 9:00 AM and 67.57 ± 5.41% at 6:00 PM, with a mean diurnal amplitude of 1.17%. Mean subfoveal CT was 287.74 ± 61.51 µm at 9:00 AM and 270.06 ± 60.73 µm at 6:00 PM. Subfoveal CT was also significantly higher at 9:00 AM compared to 6:00 PM (P < 0.0001) with a mean diurnal amplitude of 17.68 µm. Change in choriocapillaris VFD correlated with change in subfoveal CT (r = 0.87, P < 0.001). OCTA demonstrated significant diurnal change in choriocapillaris VFD in subjects without any ocular disease with VFD being higher in the morning and lower in the evening. Decrease in choriocapillaris VFD in the evening correlated with a reduction in subfoveal CT.

8 January 2019 in Journal of Ophthalmic Inflammation and Infection
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MBMillena Gomes Bittencourt
Millena Gomes Bittencourt
MHMuhammad Hassan
Muhammad Hassan
MHMuhammad Sohail Halim
Muhammad Sohail Halim
RARubbia Afridi
Rubbia Afridi
NNNam V. Nguyen
Nam V. Nguyen
YSYasir Jamal Sepah
Yasir Jamal Sepah
The aim of this study is to evaluate the differences in the fundus autofluorescence (FAF) signal between the blue light autofluorescence (BAF) from Spectralis® (Heidelberg, CA) and green light autofluorescence (GAF) 200TxTM (OPTOS, UK, in normal subjects and in patients with retinochoroidopathies (RC). In this prospective study, FAF was performed using BL (λ = 488 nm) and GL (λ = 532 nm) on normal subjects and patients with RC. The corresponding pairs of BAF and GAF images from both groups were analyzed using Photoshop. The strength of the FAF signal was measured on a gray scale, where optic disc was a standard to indicate absence of AF. In addition, gray values obtained from three identical points (foveal center, and points of hypo and hyper autofluorescence) in the corresponding BAF and GAF images of normal and RC subjects were divided by the optic disc value to calculate autofluorescence signal ratio (R). The R values at fovea (R1), hypoautofluorescent point (R2), and hyperautofluorescent point (R3) were compared between BAF and GAF modalities, in normal and in RC subjects separately. One hundred six pairs (106 eyes) of FAF images analyzed (37 pairs: normal and 69 pairs: RC subjects). In normal subjects, the mean R1, R2, and R3 values for BAF were (1.5 ± 0.88, 1.23 ± 0.58, and 4.73 ± 2.85, respectively) and for GAF were (0.78 ± 0.20, 0.78 ± 0.20, and 1.62 ± 0.39, respectively). Similarly, in subjects with RC, the mean R1, R2, and R3 values for BAF were (1.68 ± 1.02, 1.66 ± 1.15, and 7.75 ± 6.82, respectively) and for GAF were (0.95 ± 0.59, 0.79 ± 0.45, and 2.50 ± 1.65, respectively). The mean difference in the R1, R2, and R3 ratios between BAF and GAF in normal and in RC subjects was statistically significant (p < 0.001). The strength of the correlation (r) between ratios for BAF and GAF was weak or not statistically significant in both normal and RC subjects (p > 0.05). The distribution and intensity of the AF signal differ in BAF and GAF and cannot be used interchangeably. In BAF, optic disc signal is always weaker than in other areas, which was not true for GAF where optic disc signal was stronger than fovea and hypoautofluorescent point in both groups.

13 December 2019 in International Journal of Retina and Vitreous
Verified
Journal Article
Open access
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NNNam V. Nguyen
Nam V. Nguyen
EVErin M. Vigil
Erin M. Vigil
MHMuhammad Hassan
Muhammad Hassan
MHMuhammad S. Halim
Muhammad S. Halim
SBSean C. Baluyot
Sean C. Baluyot
YSYasir J. Sepah
Yasir J. Sepah
Background: The ETDRS stereoscopic seven-field (7F) has been a standard imaging and grading protocol for assessment of diabetic retinopathy (DR) severity score in many clinical trials. To the best of our knowledge, the comparison between montage and stereoscopic 7F has not been reported in the literature. Therefore, the main purpose of this study is to compare agreement between montage and stereoscopic seven-field (7F) photographs in the assessment of DR severity. Methods: Stereoscopic 7F photographs were captured from subjects with DR. Montages of monoscopic 7F images were created using Adobe Photoshop CS6 Extended©. The best quality image of each stereo pair was selected and placed on a 150 × 125-inch canvas field according to the standard location from field 1 to 7. All the fields were aligned following the vessels and overlaid using the built-in blending tool. The resulting montage was utilized for grading and compared with grading on stereoscopic 7F photographs. Three independent graders were asked to assess DR severity on stereoscopic 7F photographs and montage. Severity level agreement between stereo 7F and montage was cross-tabulated and the agreement of DR severity levels between stereoscopic 7-field images and montage was analyzed using κ intergrader agreement; statistical significance was set at p < 0.05. Results: A total of 50 eyes were included in the study. There was a substantial agreement between stereoscopic 7F and montage (κ = 0.745, κweighted = 0.867) in assessment of DR severity. Of 50 eyes, 80% of the cases showed complete agreement, and 100% of the cases had agreement within one-step. There was a moderate agreement among graders, and κ-value ranged from 0.4705 to 0.5803. Conclusion: In this study, we found a substantial agreement in assessing DR severity score employing non-stereoscopic montage and stereoscopic 7F photographs.

19 July 2019 in Journal of Ophthalmic Inflammation and Infection
Verified
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FIfor the STOP-Uveitis Investigators
for the STOP-Uveitis Investigators
MHMuhammad Hassan
Muhammad Hassan
NNNam V. Nguyen
Nam V. Nguyen
MHMuhammad Sohail Halim
Muhammad Sohail Halim
RARubbia Afridi
Rubbia Afridi
YSYasir J. Sepah
Yasir J. Sepah
To evaluate the role of vitreomacular adhesion (VMA) in visual and anatomic outcomes in patients with non-infectious uveitis. Phase 2 clinical trial Data from the Safety, Tolerability, and Efficacy of Tocilizumab in Patients with Non-infectious Uveitis (STOP-Uveitis) study was analyzed. In the STOP-Uveitis study, patients with non-infectious uveitis (NIU) received monthly intravenous infusions of either 4 or 8 mg/kg tocilizumab until month 6 (M6). Spectral domain optical coherence tomography (SD-OCT) images of patients that completed M6 of the study were analyzed at baseline to stratify the patients by the presence (VMA+) or absence (VMA−) of VMA. Patients with vitreomacular traction (VMT) or epiretinal membrane causing structural abnormalities within center 1 mm were excluded. All images were graded by two independent graders. Mean change in best-corrected visual acuity (BCVA), central retinal thickness (CRT), and vitreous haze (VH) at M6. Out of 37 patients randomized in the STOP-Uveitis study, 48 eyes (27 patients) were eligible based on the study criteria. At baseline, 19 eyes were classified as VMA+, and 32 eyes were classified as VMA−. The distribution of two doses of TCZ (4 mg/kg and 8 mg/kg) were similar between the two groups. At M6, the mean improvement in BCVA was 2.00 ± 5.3 and 6.50 ± 7.98 letters in the VMA+ and VMA− groups, respectively (p = 0.02). The mean improvement in CRT was 34.85 ± 72.36 and 80.37 ± 157.21 μm in the VMA+ and VMA− groups, respectively (p = 0.18). Similarly, the mean change in VH was − 0.65 ± 0.47 and − 0.76 ± 0.71 in the VMA+ and VMA− groups, respectively (p = 0.32). Out of 16 eyes with VMA at baseline, 3 eyes developed posterior vitreous detachment (PVD) at M6. The mean change in BCVA was significantly higher (p = 0.02), while CRT and VH score were similar (p > 0.05) in eyes with PVD compared to eyes with persistent VMA. The absence of VMA or development of PVD in eyes with VMA seems to have a beneficial effect on the vision of subjects receiving treatment for uveitis. Therefore, patients with uveitis should be assessed using SD-OCT for the presence of vitreomacular interface abnormalities.

24 November 2021 in International Journal of Retina and Vitreous
Verified
Journal Article
Open access
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MHMuhammad Hassan
Muhammad Hassan
MHMuhammad Sohail Halim
Muhammad Sohail Halim
RARubbia Afridi
Rubbia Afridi
NNNam V. Nguyen
Nam V. Nguyen
QNQuan Dong Nguyen
Quan Dong Nguyen
YSYasir J. Sepah
Yasir J. Sepah
Background: To evaluate spectral domain optical coherence tomography (SD-OCT) findings as biomarkers in primary central nervous system lymphoma (PCNSL) with or without ocular involvement. Methods: This study was a cross-sectional study and patients with a confirmed diagnosis of PCNSL with or without ocular involvement were included. Patient cohort finder tool was used to identify patients with lymphoma using ICD-10 codes (C82–C88), from January 2004 to October 2017. A total of 14,820 patients were identified. Procedure code (92134) for optical coherence tomography (OCT) was then applied to identify patients who had underdone OCT imaging at ophthalmology clinic. Clinic charts of 460 patients with lymphoma and available OCT were reviewed to identify patients with confirmed diagnosis of PCNSL and divided into two groups (Group 1: with and Group 2: without ocular involvement). OCT scans of patients in both study groups were analyzed for the presence of (1) Hyperreflective deposits in choroid, retinal pigment epithelium (RPE), outer and inner retina; (2) RPE thickening; (3) Vitreous debris; (4) Intraretinal fluid; (5) Ellipsoid zone disruption by masked graders. Chi-square was used to analyze the difference between the groups. Results: Twenty-two eyes (11 patients) with PCNSL were included this study (Group 1: 6 eyes and Group 2: 16 eyes). Mean age of subjects was 65 years. Five patients (45.45%) were female. There was no statistically significant difference between the groups for the presence of hyperreflective deposits in choroid, RPE, outer and inner retina, and presence of RPE thickening, intraretinal fluid, and ellipsoid zone disruption. Vitreous debris was found more commonly in group 1 subjects (83%) than group 2 (31.25%) (p = 0.029). All subjects in both groups showed hyperreflective deposits in the RPE demonstrating RPE infiltration. However, RPE thickening was noted only in 3 patients (Group1: 1 and Group2: 2). Conclusions: OCT finding of hyperreflective deposits present in eyes with lymphoma secondary to PCNSL are also observed in eyes with PCNSL without ocular disease. However, the vitreous deposits are more commonly found in eyes with ocular disease. These hyperreflective deposits can serve as biomarkers for early detection of ocular involvement by PCNSL.