Dr. Pugazhendhi is currently working as a Postdoctoral Medical Fellow at the Department of Ophthalmology, Stanford University School of Medicine. She received her Doctor of Medicine at PSG Institute of Medical Sciences & Research, India. Her primary research interest is on studying optic disc drusen, optic neuropathies and related neuro-ophthalmic diseases. Current research areas include: 1) Analyzing Optical Coherence Tomography (OCT) and Optical Coherence Tomography Angiography (OCTA) imaging in the understanding and management of optic disc drusen and optic neuropathies, in order to identify biomarkers that can help in prediction and treatment of disease; 2) 3D visualization and OCT reconstruction of the optic nerve head to understand the structure-function relationship of the optic nerve head disorders; 3) Whole Genome Sequencing in Autosomal Dominant Hereditary Optic Disc Drusen patients to identify predictors of disease inheritance; 4) Cellular level mitochondrial function analysis and metabolic derangement in patients with optic nerve damage using human skin fibroblasts. Her future goal is to be a physician-scientist and to deliver evidence-based medicine through interdisciplinary research and clinical expertise to address the needs of patients.

Honors & Awards

  • Translational Research and Applied Medicine (TRAM) Award, Department of Medicine, Stanford University (2022-2023)

Professional Education

  • Postdoctoral Research Fellow, Byers Eye Institute, Stanford University School of Medicine
  • Research Fellowship (Cornea), Pacific ClearVision Institute, Eugene, Oregon
  • MD, PSG Institute of Medical Sciences & Research, India (2019)

Stanford Advisors

Current Research and Scholarly Interests

-Optical Coherence Tomography (OCT) and Optical Coherence Tomography Angiography (OCTA) imaging and image analysis of neuro-ophthalmic diseases.
-3D visualization and OCT reconstruction of the optic nerve head disorders
-Whole Exome Sequencing in Autosomal Dominant Optic Disc Drusen patients
-Human skin fibroblasts study to investigate cellular function in neuro-ophthalmic diseases

Lab Affiliations

All Publications

  • Multicolor Imaging of Optic Disc Drusen. Journal of neuro-ophthalmology : the official journal of the North American Neuro-Ophthalmology Society Yan, Y., Pugazhendhi, S., Beres, S. J., Liao, Y. J. 2022


    ABSTRACT: Optic disc drusen (ODD) are calcified deposits at the anterior optic nerve that are often detectable by ophthalmic imaging, including optical coherence tomography and fundus autofluorescence imaging. Multicolor (MC) imaging is a novel modality that captures reflectance of blue, green, and near-infrared laser lights with confocal scanning laser ophthalmoscopy to rapidly acquire high-resolution reflectance images of the optic disc and retina. Here, we show an eye with 3 MC imaging features of ODD, including prominent green hyperreflectance of the optic disc, green sheathing of the papillary and peripapillary vasculature (arterioles > venules), and presence of orange superficial ODD. MC imaging can provide rapid high-resolution assessment of eyes with optic nerve head elevation to help distinguish pseudopapilledema vs papilledema in children and adults without dilation, and future large studies incorporating MC imaging will help determine its contribution in the diagnosis and monitoring of ODD and assessment of other causes of optic nerve head elevation.

    View details for DOI 10.1097/WNO.0000000000001470

    View details for PubMedID 35482433

  • Multimodal Ophthalmic Imaging of Nonarteritic Anterior Ischemic Optic Neuropathy With and Without Optic Disc Drusen. Journal of neuro-ophthalmology : the official journal of the North American Neuro-Ophthalmology Society Pugazhendhi, S., Yan, Y., Liao, Y. J. 2021

    View details for DOI 10.1097/WNO.0000000000001242

    View details for PubMedID 33870937

  • Peripapillary and macular microvasculature features of non-arteritic anterior ischemic optic neuropathy. Frontiers in medicine Pugazhendhi, S., Yu, M., Zhou, G., Chen, Y., Wang, R., Liao, Y. J. 2022; 9: 1033838


    Purpose: The hallmark of non-arteritic anterior ischemic optic neuropathy (NAION) is vascular compromise to the anterior optic nerve and thinning of the retinal nerve fiber layer (RNFL) and secondary degeneration of the retinal ganglion cell body or thinning of the ganglion cell complex (GCC). This study investigates optical coherence tomography (OCT) and OCT Angiography (OCTA) changes in chronic NAION and identifies imaging biomarkers that best predict disease.Methods: We performed a retrospective case-control study of 24 chronic NAION eyes (18 patients) and 70 control eyes (45 patients) to compare both whole-eye and regional OCT, OCTA, static perimetry measurements. OCT measurements were quantified automatically using commercial software, and OCTA was analyzed using custom MATLAB script with large vessel removal to measure 154 total parameters per eye.Results: We confirmed that static perimetry mean deviation (MD) was significantly worse in chronic NAION (-13.53 ± 2.36) than control (-0.47 ± 0.72; P < 0.001) eyes, and NAION eyes had 31 mum thinner RNFL (control: 95.9 ± 25.8 mum; NAION: 64.5 ± 18.0, P < 0.001), and 21.8 mum thinner GCC compared with controls (control: 81.5 ± 4.4 mum; NAION: 59.7 ± 10.5, P < 0.001). Spearman correlation analysis of OCTA parameters reveal that vessel area density (VAD) and flux are highly correlated with visual field MD and OCT measurements. Hierarchical clustering two distinct groups (NAION and control), where standardized measurements of NAION eyes were generally lower than controls. Two-way mixed ANOVAs showed significant interaction between patient status (control and chronic NAION) and structure (optic disk and macula) for annulus VAD and flux values and mean RNFL and GCC thickness. Post-hoc tests showed this effect stems from lower peripapillary values in NAION compared to controls. Separate logistic regression models with LASSO regularization identified VAD and flux are one of the best OCTA parameters for predicting NAION.Conclusion: Ischemic insult to the optic disk is more severe likely from primary degeneration of the affected peripapillary region while macula is affected by secondary retrograde degeneration and loss of retinal ganglion cells. In addition to OCT measurements, peripapillary and macular vascular parameters such as VAD and flux are good predictors of optic nerve and retinal changes in NAION.

    View details for DOI 10.3389/fmed.2022.1033838

    View details for PubMedID 36714135

  • Comparison of outcomes of 25-gauge vs 27-gauge micro-incision vitrectomy surgery for visually significant macular membranes and full-thickness macular holes Brown, G. T., Pugazhendhi, S., Beardsley, R. M., Karth, J. W., Karth, P. A., Hunter, A. A. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2020
  • Sixth Nerve Palsy due to Metastasis of Thyroid Carcinoma in a patient on Alternative Medicine Acta Scientific Clinical Case Reports Pugazhendhi, S., C, S., Jadhav, A., Shah, V. M. 2020; 1 (6): 08-10
  • 25 vs. 27-gauge micro-incision vitrectomy surgery for visually significant macular membranes and full-thickness macular holes: a retrospective study. International journal of retina and vitreous Brown, G. T., Pugazhendhi, S., Beardsley, R. M., Karth, J. W., Karth, P. A., Hunter, A. A. 2020; 6 (1): 56


    To evaluate visual and safety outcomes for 25-gauge (25G) and 27-gauge (27G) micro-incision vitrectomy platforms (MIVS) for the treatment of epiretinal membrane and full-thickness macular holes.Retrospective analysis of all patients who underwent internal limiting membrane (ILM) peel surgery from January 2017 through December 2018. 207 cases met the eligibility criteria for inclusion. Primary endpoint was post-operative Best-Corrected Distance Visual Acuity (BCVA) at 6 months.For all patients combined, mean logMAR BCVA improved from 0.57 (± 0.40) to 0.37 (± 0.36) post-operatively (p < 0.001). For 25G ERMs, logMAR BCVA improved from 0.51 (± 0.28) to 0.30 (± 0.25) post-operatively (p < 0.001). For 27G ERMs, logMAR BCVA improved from 0.33 (± 0.28) to 0.28 (± 0.27) post- operatively (p = 0.15). For 25G FTMHs, logMAR BCVA improved from 0.87 (± 0.48) to 0.51 (± 0.44) post-operatively (p < 0.001). For 27G FTMHs, logMAR BCVA changed from 0.89 (± 0.47) to 0.96 (± 0.60).Final visual outcomes improved for both 25G and 27G ERM groups and the 25G FTMH group. Both 25G and 27G were safe and well tolerated MIVS platforms for the treatment of ERM and FTMH.

    View details for DOI 10.1186/s40942-020-00259-4

    View details for PubMedID 33292716

    View details for PubMedCentralID PMC7670804

  • Pathogenesis and Prevention of Worsening Axial Elongation in Pathological Myopia CLINICAL OPHTHALMOLOGY Pugazhendhi, S., Ambati, B., Hunter, A. A. 2020; 14: 853-873


    This review discusses the etiology and pathogenesis of myopia, prevention of disease progression and worsening axial elongation, and emerging myopia treatment modalities.Pediatric myopia is a public health concern that impacts young children worldwide and is associated with numerous future ocular diseases such as cataract, glaucoma, retinal detachment and other chorioretinal abnormalities. While the exact mechanism of myopia of the human eye remains obscure, several studies have reported on the role of environmental and genetic factors in the disease development.A review of literature was conducted. PubMed and Medline were searched for combinations and derivatives of the keywords including, but not limited to, "pediatric myopia", "axial elongation", "scleral remodeling" or "atropine." The PubMed and Medline database search were performed for randomized control trials, systematic reviews and meta-analyses using the same keyword combinations.Studies have reported that detection of genetic correlations and modification of environmental influences may have a significant impact in myopia progression, axial elongation and future myopic ocular complications. The conventional pharmacotherapy of pediatric myopia addresses the improvement in visual acuity and prevention of amblyopia but does not affect axial elongation or myopia progression. Several studies have published varying treatments, including optical, pharmacological and surgical management, which show great promise for a more precise control of myopia and preservation of ocular health.Understanding the role of factors influencing the onset and progression of pediatric myopia will facilitate the development of successful treatments, reduction of disease burden, arrest of progression and improvement in future of the management of myopia.

    View details for DOI 10.2147/OPTH.S241435

    View details for Web of Science ID 000520510500001

    View details for PubMedID 32256044

    View details for PubMedCentralID PMC7092688

  • Double-Needle Yamane Repositioning of a Previous Yamane Fixation CASE REPORTS IN OPHTHALMOLOGY Pugazhendhi, S., Ambati, B., Hunter, A. A. 2019; 10 (3): 431-437


    We describe a case of anteriorly dislocated, Yamane-fixated secondary intraocular lens (IOLs) with pigmentary dispersion syndrome. The patient presented with significant visual impairment and elevated intraocular pressure despite being maximally treated with all topical antihypertensive medications. The iris-IOL touch was confirmed by ultrasound biomicroscopy, and fundus examination revealed evidence of pigment granules on the optic disc. The previous Yamane-fixated secondary IOL was repositioned using a double-needle adaptation of Yamane technique and Kim's modification of scleral-fixated IOLs. To our knowledge, this is the first ever documented case of double-needle Yamane technique of a previous Yamane-fixated eye. In cases of inadequate capsular support, the development of new surgical techniques for the fixation of IOL continues to improve the safety and efficacy of these complicated surgeries.

    View details for DOI 10.1159/000504563

    View details for Web of Science ID 000507329000021

    View details for PubMedID 31966035

    View details for PubMedCentralID PMC6959107

  • Maxillary Zoster and Neurotrophic Keratitis following Trigeminal Block CASE REPORTS IN OPHTHALMOLOGY Cho, Y., Kwon, J., Pugazhendhi, S., Ambati, B. K. 2019; 10 (1): 61-66


    Herpes zoster ophthalmicus is commonly used to describe viral reactivation from the trigeminal ganglia with ocular involvement. The ophthalmic branch is the most commonly involved, whereas the maxillary and mandibular dermatomes are less commonly affected. Neurotrophic ulcer may occur secondary to intentional or inadvertent damage to the trigeminal nucleus, root, ganglion, or any segment of the ophthalmic branch of this cranial nerve. We report a case of reactivated maxillary herpes zoster combined with neurotrophic keratitis due to percutaneous 2nd and 3rd branch of trigeminal nerve block with alcohol to treat trigeminal neuralgia. A 57-year-old female came to the ophthalmology department complaining of decreased visual acuity and skin vesicle over the right lower lid and cheek. She had undergone right trigeminal nerve block for treatment of trigeminal neuralgia. Clinical examination revealed neurotrophic keratitis and maxillary herpes zoster. She was treated with oral and topical antivirals and vigorous lubrication with eye drops. Her neurotrophic keratitis showed a slow recovery. Although a few cases of herpes zoster following nerve block have been described, it would appear that a case of simultaneous maxillary herpes zoster and neurotrophic keratitis following trigeminal block has not yet been documented. It is possible that trigeminal nerve block may cause reactivation of latent virus and refractory neurotrophic keratitis.

    View details for DOI 10.1159/000496683

    View details for Web of Science ID 000467640500010

    View details for PubMedID 31097946

    View details for PubMedCentralID PMC6489053

  • Is the main lacrimal gland indispensable? Contributions of the corneal and conjunctival epithelia SURVEY OF OPHTHALMOLOGY Stevenson, W., Pugazhendhi, S., Wang, M. 2016; 61 (5): 616-627


    The ocular surface system is responsible for ensuring that the precorneal tear film is sufficient in both quality and quantity to preserve optimal vision. Tear secretion is a complex, multifactorial process, and dysfunction of any component of the ocular surface system can result in tear film instability and hyperosmolarity with resultant dry eye disease. The tear film is primarily composed of lipids, aqueous, and mucins, with aqueous accounting for most of its thickness. The aqueous is produced by the main lacrimal gland, accessory lacrimal glands, and corneal and conjunctival epithelia. Although the main lacrimal gland has long been considered an indispensable source of the aqueous component of tears, there is evidence that adequate tear secretion can exist in the absence of the main lacrimal gland. We review and discuss the basics of tear secretion, the tear secretory capacity of the ocular surface, and emerging treatments for dry eye disease.

    View details for DOI 10.1016/j.survophthal.2016.02.006

    View details for Web of Science ID 000383217000006

    View details for PubMedID 26968256