Michelle Tian Sun

All Publications

• Glaucoma and Myopia: Diagnostic Challenges. Biomolecules Sun, M. T., Tran, M., Singh, K., Chang, R., Wang, H., Sun, Y. 2023; 13 (3)

  Abstract

  The rising global prevalence of myopia is a growing concern for clinicians, as it predisposes patients to severe ocular pathologies including glaucoma. High myopia can be associated with clinical features that resemble glaucomatous damage, which make an accurate glaucoma diagnosis challenging, particularly among patients with normal intraocular pressures. These patients may also present with established visual field defects which can mimic glaucoma, and standard imaging technology is less useful in disease detection and monitoring due to the lack of normative data for these anatomically unique eyes. Progression over time remains the most critical factor in facilitating the detection of early glaucomatous changes, and thus careful longitudinal follow-up of high-risk myopic patients is the most important aspect of management. Here, we review our current understanding of the complex relationship between myopia and glaucoma, and the diagnostic challenges and limitations of current testing protocols including visual field, intraocular pressure, and imaging. Furthermore, we discuss the clinical findings of two highly myopic patients with suspected glaucoma.

  View details for DOI 10.3390/biom13030562

  View details for PubMedID 36979497

• Blood Pressure Measures and Incident Primary Open-Angle Glaucoma. Investigative ophthalmology & visual science Macri, C., Wong, C. X., Tu, S. J., Casson, R., Singh, K., Wang, S. Y., Sun, M. T. 2022; 63 (13): 3

  Abstract

  To investigate the association of systemic blood pressure and incident primary open-angle glaucoma (POAG) using a large open-access database.Prospective cohort study included 484,268 participants from the UK Biobank without glaucoma at enrollment. Incident POAG events were recorded through assessment visits, hospital inpatient admissions, and primary care data. Blood pressure measures included systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP), and mean arterial pressure (MAP). Repeated measurements throughout the study period were analyzed as time-varying covariables. The parameters were modeled as both categorical and continuous nonlinear variables. The primary outcome measure was the relative hazard of incident POAG.There were 2390 incident POAG events over 5,715,480 person-years of follow-up. Median follow-up was 12.08 years. In multivariable analyses, compared to SBP and PP in the normal range (SBP, 120-130 mmHg; PP, 40-50 mmHg), higher SBP and PP were associated with an increased risk of incident POAG (linear trend P = 0.038 for SBP, P < 0.001 for PP). Specifically, SBP of 130 to 140 mmHg or 140 to 150 mmHg was associated with a 1.16 higher hazard of incident POAG (95% CI, 1.01-1.32 and 1.01-1.33, respectively), whereas a PP of greater than 70 mmHg was associated with a 1.13 higher hazard of incident glaucoma (95% CI, 1.00-1.29). In multivariable models, no statistically significant associations were found for DBP or MAP with incident glaucoma. These findings were similar when blood pressure measures were modeled as continuous variables.Higher SBP and PP were associated with an increased risk of incident POAG. Further studies are required to characterize these relationships better.

  View details for DOI 10.1167/iovs.63.13.3

  View details for PubMedID 36469027

• Real-World Outcomes of Glaucoma Filtration Surgery using Electronic Health Records: An Informatics Study. Journal of glaucoma Sun, M. T., Singh, K., Wang, S. Y. 2022

  Abstract

  PRECIS: Utilising an automated pipeline for data extraction from electronic health records provides real-world information on the success of various glaucoma procedures, with tube shunt implantation associated with increased failure rates compared with trabeculectomy.BACKGROUND: We aimed to evaluate long-term survival of glaucoma surgeries using an automated pipeline for extraction of outcomes from electronic health records.METHODS: Retrospective observational study from a single academic center. Patients undergoing trabeculectomy, Ex-PRESS shunt, Baerveldt and Ahmed tube shunt insertion from 2009-2018 were identified from electronic health record procedure codes. Patient characteristics were identified from structured and unstructured fields using a previously validated natural language processing pipeline.RESULTS: 512 patients underwent 711 glaucoma surgeries: 287 trabeculectomies, 47 Ex-PRESS shunts, 274 Baerveldt and 103 Ahmed tube implantations. Median follow-up was 359 days. Mean baseline IOP was 24.4mmHg (SD 10.9) and 73.1% were on ≥3 medications. Compared to trabeculectomy, tube shunt surgery had higher risk of failure (Baerveldt: Hazard Ratio (HR) 1.44, 95% CI 1.02-2.02; Ahmed: HR 2.01, 95% CI 1.28-3.17). Previous glaucoma surgery was associated with increased failure (≥2 previous surgeries: HR 2.74, 95% CI 1.62-4.64), as was fewer baseline medications (<3 medications: HR 2.96, 95% CI 2.12-4.13) and male sex (HR 1.40, 95% CI 1.03-1.90). At 1-year, tube shunt patients had a 2.53mmHg (P=0.002) higher IOP compared to trabeculectomy patients.CONCLUSIONS: Baerveldt and Ahmed tube shunt implantation was associated with increased failure compared with trabeculectomy. Fewer baseline medications, previous glaucoma surgeries, and male sex were also risk factors for failure. These results demonstrate the utility of applying an informatics pipeline to electronic health records to investigate key clinical questions using real-world evidence.

  View details for DOI 10.1097/IJG.0000000000002122

  View details for PubMedID 36223316

• Structural and Metabolic Imaging after Short-term Use of the Balance Goggles System in Glaucoma Patients: A Pilot Study. Journal of glaucoma Sun, M. T., Beykin, G., Lee, W. S., Sun, Y., Chang, R., Nunez, M., Li, K. Z., Knasel, C., Rich, C., Goldberg, J. L. 2022

  Abstract

  Short-term use of the Balance Goggles System in glaucoma patients was not associated with observable changes in conventional OCT imaging but metabolic imaging using peripapillary flavoprotein fluorescence may represent a useful adjuctive investigation.To determine whether the intraocular pressure (IOP)-lowering effects of the Balance Goggles System (BGS) are accompanied by changes in retinal thickness measured by ocular coherence tomography, retinal vascular density measured by OCT-angiography, or novel peripapillary metabolic profiling using flavoprotein fluorescence (FPF) measured by a fundus camera.Prospective comparative case-series.8 eyes from 8 patients with open-angle glaucoma ranging from mild to severe.In this prospective, single-center, open-label, non-randomized, single-arm study patients received a baseline evaluation including retinal imaging, then one hour of negative pressure application through the BGS, followed by repeat retinal imaging. Participants then used the BGS at home for 1 month and underwent a repeat evaluation at the conclusion of the trial.Changes in nerve fiber layer thickness, OCTA vascular parameters and FPF scores.Mean baseline IOP was 18.0±3.1 mmHg and there was no significant change in IOP at follow-up. At 1 month compared to baseline, there was a statistically significant improvement in FPF optic nerve head rim scores (12.7±11.6 to 10.5±7.5; P=0.04). Additionally, there was there was a trend towards an increase in RNFL thickness after 1 month (69.5±14.2 to 72.0±13.7; P=0.1), but there were no statistically significant differences observable with any of the OCTA vascular parameters either at 1 hour or after 1 month.There were no significant changes observable using conventional OCT imaging following short-term use of the BGS, although metabolic imaging using FPF may be a useful potential biomarker to complement existing investigations. Additional studies are warranted to further investigate these changes.

  View details for DOI 10.1097/IJG.0000000000002066

  View details for PubMedID 35696700

• Impact of Type 2 Diabetes Mellitus and Insulin Use on Progression to Glaucoma Surgery in Primary Open Angle Glaucoma Sun, M. T., Pershing, S., Goldberg, J. L., Wang, S. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2022

  View details for Web of Science ID 000844401305018

• Changes in glaucoma management following visual field testing and optical coherence tomography. The British journal of ophthalmology Sun, M. T., Singh, K., Wang, S. Y. 2022

  Abstract

  BACKGROUND: Optimal utilisation of investigations in glaucoma management remains unclear. We aimed to assess whether a temporal association exists between such testing and management changes.METHODS: Retrospective observational study using nationwide healthcare insurance claims database. Glaucoma outpatient encounters from patients aged ≥40 years with/without Humphrey visual field (HVF) and/or optical coherence tomography (OCT) were identified. An encounter was considered associated with an intervention if surgery occurred within 90 days, or if medication change or laser trabeculoplasty (LT) occurred within 30 days.RESULTS: 12 669 324 outpatient encounters of 1 863 748 individuals from 2003 to 2020 were included. HVF and OCT was performed during 32.8% and 22.2% of encounters respectively. Of the 36 763 (0.3%) encounters preceding surgery, 28.1% included HVF, 11.9% had OCT and 8.5% both. 79 181 (0.6%) visits preceded LT, of which 28.2% had HVF, 13.2% OCT and 9.3% both. Of the 515 899 (4.5%) encounters preceding medication changes, 29.1% had HVF, 16.7% OCT and 12.2% both. Compared with encounters with no investigations, those with HVF and/or OCT were associated with a 49% increased odds of a management change (p<0.001). In multivariate analyses, compared with encounters without investigations, visits with HVF alone had higher odds of subsequent surgery and LT, while HVF and/or OCT were associated with higher odds of medication change (p<0.001 for all).CONCLUSION: Glaucoma therapeutic changes occurred following approximately 5% of outpatient encounters. Surgery and LT were more likely to occur following a visit with a HVF rather than an OCT, while either investigation was associated with a higher odds of medication change.

  View details for DOI 10.1136/bjophthalmol-2021-321010

  View details for PubMedID 35450937