Michael W. Stewart

Michael W. Stewart

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Michael W. Stewart has a total of 126 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Advancements in Visual Field Testing: A Systematic Review of the 24-2C Test Grid

    by Eric Jin, Natalie Shi Qi Wong, Claire Xin Yi Goh, Michael W. Stewart, Syril Dorairaj, Bryan Chin Hou Ang

    A systematic review was conducted of studies published up to 30 August 2024. Studies comparing conventional visual field (VF) indices, ability to detect central visual field defects (CVFDs), structure–function (S-F) concordance, and test characteristics across the HVF 24-2C SITA-Faster, 24-2 SITA-Standard/Faster, and 10-2 SITA-Standard/Fast tests were included. Eight studies with 1239 subjects (49.1% male; mean age, 54.8–66.9 years) were analyzed. The 24-2C produced similar global VF indices compared to the 10-2 and 24-2 (Standard/Faster) (ICC = 0.95 and 0.80, p < 0.001), detected more VF defects and CVFD clusters, and demonstrated greater S-F concordance than the 24-2 (Standard/Faster). Although the 10-2 (Standard/Fast) detected significantly more CVFDs and had a greater S-F concordance, the agreement between the 24-2C and 10-2 grids was substantial (ĸ = 0.488 to 0.708). The 24-2C was also faster compared to the 24-2 Standard and 10-2 (Standard/Fast), with comparable false positives, higher false negatives, and fewer fixation losses than the 24-2 Standard. In conclusion, the HVF 24-2C is quicker and identifies more CVFDs than the 24-2 grid, demonstrates high agreement with the 10-2 grid, and aids in CVFD screening.


  • Open Access

    Anatomic Characteristics of Eyes With Fuchs Endothelial Corneal Dystrophy

    by Darby D. Miller, Isabella V. Bs Wagner, Syed A. Bs Hasan, Michael W. Stewart, Caleb M. Bs Towne, Zhuo Li, Keith H. Baratz

    Purpose: The purpose of this study was to evaluate and compare the anatomic characteristics of eyes with Fuchs endothelial corneal dystrophy (FECD) with eyes without FECD. Methods: This study was a retrospective chart review performed at an academic medical center. Patients with FECD were identified through a search of the electronic medical records. Eligible patients underwent Scheimpflug imaging and optical biometry and were compared with age and sex-matched control subjects who underwent similar testing in preparation for cataract surgery. Several measurements of the cornea, anterior chamber, and eyes were evaluated using multivariable linear regression models and multivariable logistic regression models. Results: A total of 404 eyes (202 eyes with FECD and 202 control eyes) were included in this study. Compared with controls, eyes with FECD had shallower AC depths, lower AC volumes, and narrower angles. Conversely, the spherical equivalent before cataract surgery, corneal pachymetry, and corneal volume were higher in eyes with FECD. On Scheimpflug imaging analysis, these anatomical differences were present in FECD eyes with and without corneal edema. After adjusting for sex, these differences remained statistically significant. Shorter axial length was found to be statistically significant in male eyes but not in female eyes with FECD. Conclusions: This study reports new ocular characteristics in FECD eyes with and without edema. Optical biometry and Scheimpflug imaging established that the anatomic findings in eyes with FECD were not simply due to the larger volume of an edematous cornea but rather unique to eyes with FECD. These findings will provide reliable, normative data for future studies examining surgical, medical, and anatomical factors in FECD.


  • MEDICAL THERAPY FOR LARGE IDIOPATHIC FULL-THICKNESS MACULAR HOLES

    by Young Ba Sheng, Mukesh Jain, Niroj Sahoo, Nikitha Reddy, Mudit Tyagi, Ritesh Narula, Michael W. Stewart, Raja Narayanan

    Purpose: To describe the characteristics and outcomes of eyes with idiopathic full-thickness macular holes that underwent initial medical management. Methods: This retrospective study included eyes with full-thickness macular holes that were initially managed with 1 month of topical therapy. Eligible subjects were treated with dorzolamide 2% three times a day, nepafenac 0.1% twice a day, and prednisolone acetate 1% four times a day. The primary end points was hole closure at one month and secondary end point was change in best-corrected visual acuity. Results: Ten subjects (mean age: 62.80 years; female: 50%) with unilateral full-thickness macular holes were studied. The mean basal diameter of the entire cohort at baseline was 824.1 µm (median 828 µm). Four (40%) of the smaller holes (mean 698 µm; median 698.50 µm) closed after 1 month of topical therapy, whereas larger holes (mean 908.17 µm; median 889.50 µm) did not close. In one eye, the hole reopened 4 months after stopping the medication but closed again at 1 month after restarting the topical treatment. Median best-corrected visual acuity improved from 0.35 logMAR at baseline to 0.05 logMAR in eyes that closed but remained at 0.70 logMAR at 1 month in eyes that did not close. Conclusion: Topical corticosteroid, nonsteroidal antiinflammatory, and carbonic anhydrase inhibitor therapy may promote closure of small full-thickness macular holes, but large holes are less likely to respond. One month of topical therapy might avoid subjecting some patients to complex vitreoretinal surgery without compromising visual outcomes. Macular hole may reopen after stopping the topical therapy.


  • Open Access

    The Role of Widefield Optical Coherence Tomography Angiography in Assessing the Severity of Diabetic Retinopathy

    by Deepika C. Parameswarappa, Amelia Janis Langstang, Sanagavarapu Kavya, Ashik Mohamed, Michael W. Stewart, Padmaja Kumari Rani

    Introduction Physicians need an accurate understanding of diabetic retinopathy (DR) severity to optimally manage patients. The aim of this prospective study is to correlate the severity of macular and peripheral retinal vascular abnormalities seen on widefield (WF) optical coherence tomography angiography (OCTA) with DR grading based on WF fundus photography. Methods The study included 150 eyes from 82 patients with treatment-naïve DR. All patients were imaged with WF fundus photography and swept-source WF OCTA. Quantitative and qualitative analyses of the foveal avascular zone (FAZ) size and shape, and measurement of capillary nonperfusion (CNP) areas, were performed from the OCTA images. The mixed-effects model was used to compare the DR grading from WF photography with the vascular changes seen on WF-OCTA, and Bonferroni correction was applied to the gradings. Results The mean [± standard deviation (SD)] age of patients was 55.5 (± 9.4) years. The WF-OCTA showed that an increasing size of the FAZ (from 0.442 (± 0.059) µm to 0.933 (± 0.086) µm) correlated with increasing severity of the DR (as determined with WF photography). The deep capillary plexus, FAZ size, and CNP areas in eyes with proliferative diabetic retinopathy (PDR) differed from those with mild nonproliferative diabetic retinopathy (NPDR) (p < 0.001). Most eyes with severe nonproliferative DR were found to have CNP in four quadrants [superficial capillary plexus (SCP) 60%, deep capillary plexus (DCP) 50%]. The WF-OCTA detected subtle neovascularization of the disc (NVD) in 7 eyes (10%) and neovascularization elsewhere (NVE) in 13 eyes (18%) that had been diagnosed with only moderate NPDR on WF photography. Conclusions FAZ and CNP areas as measured by WF-OCTA correlate with DR severity. WF-OCTA can also detect subtle NVE and NVD that cannot be seen with fundus photography.


  • Open Access

    Recent Updates on the Diagnosis and Management of Age-Related Macular Degeneration

    by Nithya Boopathiraj, Isabella V. Wagner, Syril K. Dorairaj, Darby D. Miller, Michael W. Stewart


  • Open Access

    Real-world experience of full-thickness traumatic macular hole among young patients

    by Ragukumar Venugopal, Anthony Vipin Das, Brijesh Takkar, Michael W. Stewart, Raja Narayanan

    Objective: To describe the demographics, clinical, and imaging characteristics, and visual outcomes in young patients with full-thickness traumatic macular hole (TMH). Methods: This retrospective hospital-based study included patients with full-thickness TMH who presented between August 2010 and June 2021. Demographic data, clinical findings, and imaging characteristics were extracted from an electronic medical record system. Regression analyses were performed to determine significant associations among variables and to identify predictors of visual outcomes. Results: 144 (0.005%) patients among 2,834,616 were diagnosed with Full thickness TMH. The majority of them were male (89.58%; odds ratio [OR] = 6.71) and the holes were unilateral. The mean age at presentation was 23.37 ± 8.19 years. Ball were the most common cause of injuries (22.22%), followed by stick (14.58%) and firecracker (12.50%). The mean LogMAR visual acuity (VA) at presentation was 1.18 ± 0.72, with 25.69% of eyes having VA < 20/400. The mean minimum hole diameter was 619.34 ± 336.16 μm. Sub-retinal fluid was present in 44.44%, followed by intraretinal fluid in 34.03% of eyes. Macular holes closed after vitrectomy in 66.67% of eyes, with mean final VA of 1.07 ± 0.85. Baseline VA was a strong predictor of final VA (R2 = 0.677; p = 0.000168). Conclusion: Traumatic macular hole is a unilateral condition with significant visual impairment that is mainly seen in males during the third decade of life. Surgery is successful in most cases but improvements in VA are modest.


  • Open Access

    Extended Duration Anti-VEGF Therapy for Chorioretinal Vascular Diseases: Successes, Failures and Challenges

    by Azeem Hasan, Darby D Miller, Michael W. Stewart

    Pathologic angiogenesis is responsible for much of the vision loss that stems from several chorioretinal vascular diseases including neovascular age-related macular degeneration (nAMD), diabetic retinopathy (DR), and retinal vein occlusion (RVO). Because vascular endothelial growth factor (VEGF) serves as a pivotal angiogenic molecule, it has emerged as the primary target for therapeutic drugs. Current anti-VEGF therapy is dominated by bevacizumab, ranibizumab, and aflibercept, all of which have been available for more than a decade, but new drugs, both biosimilars (Byooviz and Cimerli) and drugs whose primary aim is to decrease treatment burden (brolucizumab, faricimab, and the ranibizumab port delivery system), have been approved. Recent failures (conbercept, abicipar, and KSI-301) emphasize the complexity of drug development and the difficulties faced by innovators. Most therapies under development, including tyrosine kinase inhibitors and gene therapy, include VEGF-A blockade as their primary function and aim to extend durability rather than increase peak efficacy. But even as many new drugs look to extend durability, cost containment with mandated use of biosimilars serves to balance the therapeutic landscape.

  • Open Access

    Recent Advancements in Glaucoma Surgery—A Review

    by Bryan Chin Hou Ang, Sheng Yang Lim, Bjorn Kaijun Betzler, Hon Jen Wong, Michael W. Stewart, Syril Dorairaj

    Surgery has long been an important treatment for limiting optic nerve damage and minimising visual loss in patients with glaucoma. Numerous improvements, modifications, and innovations in glaucoma surgery over recent decades have improved surgical safety, and have led to earlier and more frequent surgical intervention in glaucoma patients at risk of vision loss. This review summarises the latest advancements in trabeculectomy surgery, glaucoma drainage device (GDD) implantation, and minimally invasive glaucoma surgery (MIGS). A comprehensive search of MEDLINE, EMBASE, and CENTRAL databases, alongside subsequent hand searches—limited to the past 10 years for trabeculectomy and GDDs, and the past 5 years for MIGS—yielded 2283 results, 58 of which were included in the final review (8 trabeculectomy, 27 GDD, and 23 MIGS). Advancements in trabeculectomy are described in terms of adjunctive incisions, Tenon’s layer management, and novel suturing techniques. Advancements in GDD implantation pertain to modifications of surgical techniques and devices, novel methods to deal with postoperative complications and surgical failure, and the invention of new GDDs. Finally, the popularity of MIGS has recently promoted modifications to current surgical techniques and the development of novel MIGS devices.


  • Open Access

    Doctor I Have an Iodine Allergy

    by Michael W. Stewart

    Ophthalmologists frequently face patients who refuse asepsis protocols involving povidone-iodine (PI) due to claims of an allergy to iodine. Such patients usually base this claim on previous reactions to shellfish consumption or to imaging procedures that used iodine-based contrast agents. Allergy to iodine, however, is biologically impossible, and iodine deficiency causes severe developmental problems, including mental retardation. Furthermore, shellfish allergy is due to tropomyosins in muscle tissue, and reactions to intravascular contrast dyes are due to hyperosmolar solutions; neither “allergy” is due to iodine. PI, which contains 9–12% iodine, is the preferred antiseptic for ophthalmic procedures. Experience shows that PI can be administered safely to patients claiming iodine allergy. True allergy to PI is rare and, if indicated, skin patch testing can be performed prior to surgery. Patients who react adversely to highly concentrated (5–10%) PI usually experience toxicity to the corneal and conjunctival epithelium after topical administration. Dilute (0.1–0.25%) PI kills microbes quicker than higher concentrations but for shorter periods of time because the total dose of iodine is smaller. Repeated administration (every 20–30 s) of dilute PI effectively kills microbes for as long as necessary with little risk of epithelial toxicity.


  • SAFETY AND THERAPEUTIC EFFECTS OF ORALLY ADMINISTERED AKST4290 IN NEWLY DIAGNOSED NEOVASCULAR AGE-RELATED MACULAR DEGENERATION

    by Michael W. Stewart, Seema Garg, Erin McCaskill Newman, Elizabeth Jeffords, Joanna Konopińska, Sam Md Jackson, Bartosz L. Sikorski, Esther S. Rawner

    Purpose: To evaluate the safety and therapeutic effects of orally administered AKST4290 (formerly BI 144807 and ALK4290) in treatment-naive patients with neovascular age-related macular degeneration. Methods: In this prospective, multicenter, open-label Phase 2a pilot clinical study, 30 patients with newly diagnosed neovascular age-related macular degeneration self-administered AKST4290 (400 mg) orally twice daily for 6 weeks. Patients were examined weekly for safety, to measure best-corrected visual acuity (BCVA), and to perform exploratory morphologic assessments. The primary endpoint was the mean change in BCVA from baseline to end of treatment, and the secondary endpoint was safety. Exploratory endpoints investigated potential changes in macular morphology. Results: Mean BCVA improved by +7.0 letters (95% CI, 2.2–11.7); 24 patients (82.8%) had stable or improved BCVA, with 6 (20.7%) gaining ≥15 letters. No patients experienced severe or serious adverse events. Conclusion: In this 6-week study, AKST4290 treatment was associated with improved BCVA scores in patients with treatment-naive neovascular age-related macular degeneration. All adverse events were mild or moderate in severity and no safety issues were identified. Treatment of neovascular age-related macular degeneration with AKST4290 warrants further investigation in randomized, placebo-controlled trials.