IU Indianapolis ScholarWorks :: Browsing by Author "Hajrasouliha, Amir R."

Browsing by Author "Hajrasouliha, Amir R."

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Clinical implications of retinal oximetry in retinal vein occlusion: a review
(Wiley, 2022) Belamkar, Aditya V.; Jabbehdari, Sayena; Harris, Alon; Hajrasouliha, Amir R.; Ophthalmology, School of Medicine
Purpose: To review retinal vein occlusion (RVO) and its relationship with retinal oxygen saturation via automated retinal oximetry in eyes with RVO. Methods: A literature review was performed in PubMed and Medline until October 2021 utilizing specific keywords and cross-matched reference lists. Results: This review found RVO to be associated with risk factors including age, hypertension, cardiovascular and metabolic conditions, male gender, and glaucoma. These may be attributed to a breakdown of regulatory processes in the retina. Retinal venous oxygen saturation (SvO2 ) and arteriovenous difference in eyes with central RVO have been found to be reduced and elevated, respectively. The literature indicates variable and contradictory findings in regard to branch RVO and retinal oxygenation. Additionally, ischaemic eyes have been found to have elevated retinal arterial oxygen saturation; however, the literature reports variable results regarding SvO2 levels. Medications have been suggested to increase SvO2 in RVO eyes, which may represent an important mechanism for disease management. Ranibizumab is currently the most studied drug for retinal oxygenation in RVO and has been suggested to increase SvO2 in RVO eyes. In comparison, dexamethasone was found to decrease SvO2 . Conclusion: The current literature on retinal oxygenation in ischaemic subtypes of RVO and in drug therapies is minimal, and further work is required to expand upon our understanding of how ischaemia and drugs influence retinal oxygenation and clinical outcomes.
Combining transfer learning with retinal lesion features for accurate detection of diabetic retinopathy
(Frontiers Media, 2022-11-08) Hassan, Doaa; Gill, Hunter Mathias; Happe, Michael; Bhatwadekar, Ashay D.; Hajrasouliha, Amir R.; Janga, Sarath Chandra; BioHealth Informatics, School of Informatics and Computing
Diabetic retinopathy (DR) is a late microvascular complication of Diabetes Mellitus (DM) that could lead to permanent blindness in patients, without early detection. Although adequate management of DM via regular eye examination can preserve vision in in 98% of the DR cases, DR screening and diagnoses based on clinical lesion features devised by expert clinicians; are costly, time-consuming and not sufficiently accurate. This raises the requirements for Artificial Intelligent (AI) systems which can accurately detect DR automatically and thus preventing DR before affecting vision. Hence, such systems can help clinician experts in certain cases and aid ophthalmologists in rapid diagnoses. To address such requirements, several approaches have been proposed in the literature that use Machine Learning (ML) and Deep Learning (DL) techniques to develop such systems. However, these approaches ignore the highly valuable clinical lesion features that could contribute significantly to the accurate detection of DR. Therefore, in this study we introduce a framework called DR-detector that employs the Extreme Gradient Boosting (XGBoost) ML model trained via the combination of the features extracted by the pretrained convolutional neural networks commonly known as transfer learning (TL) models and the clinical retinal lesion features for accurate detection of DR. The retinal lesion features are extracted via image segmentation technique using the UNET DL model and captures exudates (EXs), microaneurysms (MAs), and hemorrhages (HEMs) that are relevant lesions for DR detection. The feature combination approach implemented in DR-detector has been applied to two common TL models in the literature namely VGG-16 and ResNet-50. We trained the DR-detector model using a training dataset comprising of 1,840 color fundus images collected from e-ophtha, retinal lesions and APTOS 2019 Kaggle datasets of which 920 images are healthy. To validate the DR-detector model, we test the model on external dataset that consists of 81 healthy images collected from High-Resolution Fundus (HRF) dataset and MESSIDOR-2 datasets and 81 images with DR signs collected from Indian Diabetic Retinopathy Image Dataset (IDRID) dataset annotated for DR by expert. The experimental results show that the DR-detector model achieves a testing accuracy of 100% in detecting DR after training it with the combination of ResNet-50 and lesion features and 99.38% accuracy after training it with the combination of VGG-16 and lesion features. More importantly, the results also show a higher contribution of specific lesion features toward the performance of the DR-detector model. For instance, using only the hemorrhages feature to train the model, our model achieves an accuracy of 99.38 in detecting DR, which is higher than the accuracy when training the model with the combination of all lesion features (89%) and equal to the accuracy when training the model with the combination of all lesions and VGG-16 features together. This highlights the possibility of using only the clinical features, such as lesions that are clinically interpretable, to build the next generation of robust artificial intelligence (AI) systems with great clinical interpretability for DR detection. The code of the DR-detector framework is available on GitHub at https://github.com/Janga-Lab/DR-detector and can be readily employed for detecting DR from retinal image datasets.
Modeling of external self-excitation and force generation on magnetic nanoparticles inside vitreous cavity
(AIMS Press, 2021) Parker, Evan; Mitchell, Chandler S.; Smith, Joshua P.; Carr, Evan; Akbari, Rasul; Izadian, Afshin; Hajrasouliha, Amir R.; Ophthalmology, School of Medicine
The purpose of this manuscript was to design a better method for recovery from rhegmatogenous retinal detachment (RRD) surgery. We attempted to achieve this by designing a helmet that can manipulate intraocular magnetic nanoparticles (MNPs) and create a magnetic tamponade, eliminating the need for postoperative head positioning. A simulated analysis was developed to predict the pattern of magnetic force applied to the magnetic nanoparticles by external magnetic field. No participants were involved in this study. Instead, magnetic flux and force data for three different helmet designs were collected using virtual simulation tools. A prototype helmet was then constructed and magnetic flux and force data were recorded and compared to virtual data. For both virtual and physical scenarios, magnitude and direction of the resulting forces were compared to determine which design created the controlled direction and strongest forces into the back of the eye. Of the three virtual designs, both designs containing a visor had greater force magnitude than magnet alone. Between both designs with visors, the visor with bends resulted in forces more directed at the back of the eye. The physical prototype helmet shared similar measurements to virtual simulation with minimal percent error (Average = 5.47%, Standard deviation = 0.03). Of the three designs, the visor with bends generated stronger forces directed at the back of the eye, which is most appropriate for creating a tamponade on the retina. We believe that this design has shown promising capability for manipulating intraocular MNPs for the purpose of creating a tamponade for RRD.
Perinatal events and development of juvenile idiopathic arthritis-associated uveitis
(Springer Nature, 2023-10-16) Chaudhary, Aysha; Nadeem, Manahil; Townsend, Jack; Miller, Victoria J.; Hajrasouliha, Amir R.; Ophthalmology, School of Medicine
Uveitis is one of the most common manifestations of juvenile idiopathic arthritis (JIA). Currently, JIA is associated with decreased gut microbiota diversity. Studies confirm that perinatal events can cause aberrant microbial colonization. The objective of this study is to determine if JIA is associated with perinatal events with a secondary focus on these variables to the development of JIA-uveitis. 369 patients with strabismus (n = 200) or JIA (n = 196) were included in the study. Completed surveys (JIA 37; strabismus 18) collected data about birth route, pregnancy and labor complications, JIA medications, and the presence of eye disorders. Analysis indicates that there is no relationship between JIA development and the perinatal events investigated. Similarly, no significance was found between JIA-uveitis and birth route or labor complications. Pregnancy complications, namely gestational diabetes (GD), were statistically higher in the JIA group with uveitis compared to JIA without uveitis. The data from this survey study showed that JIA-uveitis was highly associated with pregnancy complications, particularly with GD. However, no statistically significant association was found between JIA and route of delivery, labor complications, or pregnancy complications. Further studies are needed to understand the ways that GD interrelates with the development of uveitis in JIA patients.
Ultrasound Biomicroscopy and echogenic external marker assisted Intraocular Foreign Body Removal
(Wolters Kluwer, 2024-01) Patel, Shivam H.; Bakhsh, Saaquib; Badar, Ayesha; Hajrasouliha, Amir R.; Ophthalmology, School of Medicine
Purpose: We report a novel method of intraoperative localization of a retained anterior intraocular foreign body (IOFB), using a combination of ultrasound biomicrosopy and an insulated needle. Methods: A retrospective case report of a 56-year-old man who presented with a right eye IOFB. Results: On presentation, vision was decreased in the right eye to count fingers with a small subconjunctival hemorrhage, but no other signs of a penetrating laceration. Orbital CT revealed an IOFB, and the initial vitrectomy failed to retrieve the IOFB. Then, during the subsequent vitrectomy, using an ultrasound compatible needle and an ultrasound biomicrosopy, we were able to precisely locate and remove the small anterior IOFB. Conclusion: Retained IOFBs can lead to severe irreversible vision loss if not promptly removed. Ancillary imaging modalities and localization techniques can help locate occult IOFBs in difficult cases.
Unexplained Vision Loss Associated With Intraocular Silicone Oil Tamponade in Rhegmatogenous Retinal Detachment Repair
(Sage, 2023-06-10) Pakravan, Parastou; Shaheen, Abdulla; Patel, Veshesh; Villalba, Maria F.; Dib, Bernard; Lai, James; Rohowetz, Landon; Chau, Viet; Patel, Nimesh A.; Tzu, Jonathan H.; Wang, Angeline L.; Alhoyek, Sandra; Scott, Nathan; Samara, Wasim A.; Goduni, Lediana; Jung, Jesse J.; Russell, Jonathan F.; Mantopoulos, Dimosthenis; Hajrasouliha, Amir R.; Savoie, Brian T.; Haddock, Luis J.; Berrocal, Audina M.; Sridhar, Jayanth; West, Matthew R.; Yannuzzi, Nicolas A.; Ophthalmology, School of Medicine
Purpose: To evaluate the visual outcomes with unexplained vision loss during or after silicone oil (SO) tamponade. Methods: This multicenter retrospective case series comprised patients with unexplained vision loss associated with SO tamponade or its removal. Eyes with other clear secondary identifiable causes of vision loss were excluded. Results: Twenty-nine eyes of 28 patients (64% male) were identified. The mean age was 50 ± 13 years (range, 13-78 years). The mean duration of SO tamponade was 148 ± 38 days. Eighteen eyes (62%) developed unexplained vision loss while under SO; 11 (38%) had vision loss after SO removal. The most common optical coherence tomography (OCT) finding was ganglion cell layer (GCL) thinning (55%). Eyes with vision loss after SO removal had a mean logMAR best-corrected visual acuity (BCVA) of 0.6 ± 0.7 (Snellen 20/85) before SO tamponade and 1.2 ± 0.4 (20/340) before SO removal. By the last follow-up after SO removal, the BCVA had improved to 1.1 ± 0.4 (20/235). In eyes with vision loss after SO removal, the BCVA before SO removal was 0.7 ± 0.7 (20/104), which deteriorated to 1.4 ± 0.4 (20/458) 1 month after SO removal. By the last follow-up, the BCVA had improved to 1.0 ± 0.5 (20/219). Conclusions: Unexplained vision loss can occur during SO tamponade or after SO removal. Vision loss was associated with 1000-centistoke and 5000-centistoke oil and occurred in macula-off and macula-on retinal detachments. The duration of tamponade was 3 months or longer in the majority of eyes. Most eyes had GCL thinning on OCT. Gradual visual recovery can occur yet is often incomplete.
Using optical coherence tomography angiography as a biomarker of retinopathy severity and treatment for diabetic retinopathy
(Emory University, 2022-08-19) Scheive, Melanie; Reinhart, Kathryn L.; Hajrasouliha, Amir R.; Ophthalmology, School of Medicine
Purpose: The goal was to evaluate optical coherence tomography angiography (OCT-A) as a biomarker to correlate retinal vessel density (VD) with diabetic retinopathy (DR) severity and visual acuity, as well as track antivascular endothelial growth factor (VEGF) treatment efficacy. Methods: This retrospective cohort study analyzed the automatically quantified VDs of the superficial vascular complex (SVC) and deep vascular complex (DVC), including the whole, foveal, and parafoveal VDs, on quality OCT-A scans in patients diagnosed with DR. A multivariate linear regression and analysis of variance (ANOVA) analysis compared VDs to DR severity, visual acuity, and demographic factors. A linear mixed analysis determined the effects of VD by whether anti-VEGF therapy was given to patients with OCT-A scans at multiple time points. Results: There was a positive correlation of the VDs in both the SVC whole and parafoveal VD and DVC parafoveal VD with decreased DR severity and increased visual acuity (p≤0.001). The DVC whole VD was also positively correlated with increased visual acuity (p<0.001). There was no difference in the VDs associated with anti-VEGF treatment over time. Conclusions: OCT-A VD shows promise for diagnosing and monitoring DR using DR severity and visual acuity. Anti-VEGF treatment had no significant effect (p=0.063) on vascular density in diabetic retinopathy.
Using optical coherence tomography angiography as a biomarker of retinopathy severity and treatment for diabetic retinopathy
(Molecular Vision, 2022-08-19) Scheive, Melanie; Reinhart, Kathryn L.; Hajrasouliha, Amir R.; Ophthalmology, School of Medicine
Purpose: The goal was to evaluate optical coherence tomography angiography (OCT-A) as a biomarker to correlate retinal vessel density (VD) with diabetic retinopathy (DR) severity and visual acuity, as well as track antivascular endothelial growth factor (VEGF) treatment efficacy. Methods: This retrospective cohort study analyzed the automatically quantified VDs of the superficial vascular complex (SVC) and deep vascular complex (DVC), including the whole, foveal, and parafoveal VDs, on quality OCT-A scans in patients diagnosed with DR. A multivariate linear regression and analysis of variance (ANOVA) analysis compared VDs to DR severity, visual acuity, and demographic factors. A linear mixed analysis determined the effects of VD by whether anti-VEGF therapy was given to patients with OCT-A scans at multiple time points. Results: There was a positive correlation of the VDs in both the SVC whole and parafoveal VD and DVC parafoveal VD with decreased DR severity and increased visual acuity (p≤0.001). The DVC whole VD was also positively correlated with increased visual acuity (p<0.001). There was no difference in the VDs associated with anti-VEGF treatment over time. Conclusions: OCT-A VD shows promise for diagnosing and monitoring DR using DR severity and visual acuity. Anti-VEGF treatment had no significant effect (p=0.063) on vascular density in diabetic retinopathy.
The utility and risks of therapeutic nanotechnology in the retina
(Sage, 2021-03-22) Scheive, Melanie; Yazdani, Saeed; Hajrasouliha, Amir R.; Ophthalmology, School of Medicine
The clinical application of nanotechnology in medicine is promising for therapeutic, diagnostic, and surgical improvements in the near future. Nanotechnologies in nano-ophthalmology are in the early stages of application in clinical contexts, including ocular drug and gene delivery systems addressing eye disorders, particularly retinopathies. Retinal diseases are challenging to treat as current interventions, such as intravitreal injections, are limited by their invasive nature. This review examines nanotechnological approaches to retinal diseases in a clinical context. Nanotechnology has the potential to transform pharmacological and surgical interventions by overcoming limitations posed by the protective anatomical and physiological barriers that limit access to the retina. Preclinical research in the application of nanoparticles in diagnostics indicates that nanoparticles can enhance existing diagnostic and screening tools to detect diseases earlier and more easily and improve disease progression monitoring precision.

Browsing by Author "Hajrasouliha, Amir R."

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