Chung, Lani

School of Public Health



Peru-Biomarkers In The Ocular Tears of Patients with Corneal Nerve Damage as an Early Indicator of Peripheral Neuropathy in Type 2 Diabetes

Currently, the burden of type 2 diabetes mellitus (T2DM) encompasses over 400 million individuals diagnosed worldwide, and is a major cause of cardiometabolic morbidity and mortality.  Late diagnosis of T2DM causes costly and incapacitating complications, particularly in low and middle income countries (LMIC), where only around 50% of the T2DM cases are identified before they can be successfully intervened.  Diabetic peripheral neuropathy (DPN) is a serious and progressive complication of T2DM. It causes pain, foot ulceration and the concomitant negative effect on both quality of life and ability to function. Approximately 60 of every 10,000 T2DM patients undergo a lower extremity amputation, and 80% of these amputations are due to a foot ulcer.  In Peru, an LMIC, diabetes is the leading cause of nontraumatic lower limb amputation.

Our group has worked in a National Public Hospital in Peru, and found a 57% prevalence of diabetic foot neuropathy, the main entity of DPN, among all diabetics. 25% of those cases will progress to develop diabetic foot ulcers (DFU). Due to both non-compliance and high cost of management, nearly half of those patients in Peru will progress to amputation.

Early detection of DPN is critical for the prevention of DFU development and amputation. However, current options for early detection require either a biothesiometer, rarely available in Peru, or nerve conduction studies also either not done or rarely available. Recently, studies have demonstrated that corneal nerve fibers in diabetes lose density and number and there is a correlation with diabetic peripheral neuropathy. If a simple method of testing during eye examinations could be performed that would detect corneal nerve changes that correlate with DPN, it would serve as a powerful tool for preventing foot ulcers and amputation and would be a major advance.

The proposed research aims to address the need for inexpensive, minimally-invasive methods for the early detection of DPN by studying biomarkers of DPN present in tears. We will assess the correlation, sensitivity, and specificity of several biomarker levels found in tears to predict DPN diagnosed using a biothesiometer.

PI Mentor: Robert Gilman

Although many of the other students in my cohort ended up traveling to countries that they had never been to, going to Lima for my placement was like returning home for me. Because I had gone to Peru on five other occasions with my church to serve in the city and ended up living there sometimes for months at a time, I expected my transition into working with an academic institution in Peru to be a smooth one. However, I soon realized that there were many unforeseen circumstances that presented themselves as challenges during my time there. The first was realizing that the difficulties associated with gaining Institutional Review Board approval for research projects are just the same in Peru. I did not imagine myself to spend the entirety of my time in Peru waiting for my assigned project—which was seeking to standardize the measurement of protein biomarkers designed to assess diabetic retinopathy—editing the study protocol and responding to the comments made by our reviewers. But given the state of the study’s progress when I jumped in, that is what I ended up doing for two months. Although I was a little disappointed to leave Peru without getting to see the study get off the ground, I did leave with an important understanding of the realities of research, and the skills necessary to design a protocol that is able to make it past the rigors of institutional review. This experience helped me to realize that the “fun” part of research cannot happen without the grueling details, but that this is so for very good reason. The time put into ensuring that patients are protected throughout the process of your study and working through even the minute concerns that are brought up during the review process are certainly worth it. Looking back at some of the issues that were brought up by our reviewers, I realize that it would have been very harmful to the study to overlook them and rush into commencement. Through these experiences, I recognized that there is much to learn at every stage of research, even if you end up leaving before it actually starts.

During the time that I spent working through the study protocol of the project that I was initially assigned to as my field placement, I was fortunately able to jump into another project that was also underway at my PI’s lab. Although the research involved the investigation of Chagas disease at an infectious disease laboratory where they mostly utilized lab techniques that I had little first-hand exposure to, it was still a valuable experience. I ended up learning a lot of the practical procedural elements of lab work, and also gained an understanding of the reasons why each step was being taken. The student at the lab who guided me through all these things spoke some English, but my Spanish skills were still put to the test. Despite the occasional difficulties in communication that arose because of my limited language skills, at the end of the day I was grateful for the opportunity to be pushed and challenged to understand technical Spanish—a skill that I am sure will prove useful in future endeavors working in Spanish-speaking countries. Another thing I learned through my time working at the lab was the importance of asking for opportunities to be involved instead of waiting to be asked. One of the skills that I always wanted to hone in a practical, real-life environment was data analysis. Although the work that I was assigned to did not include this component, I ended up reaching out to one of the project coordinators, and he actually gave me some preliminary data that I was able to work with. And lastly, I learned that it is important to build relationships and really immerse yourself in the culture while you are in-country to fully enjoy your time there. I was lucky to be able to hang out with and grow in friendship with many of the Peruvians I met there through work and church. We went out to their favorite places to eat, explored together, and shared experiences that I will never forget. At the end of the day, your experience will be as good as you make it.


Joanne Katz, ScD MS,BSc

Associate Chair, Director of Academic Programs

Caitlin Kennedy, PhD MPH,BA

Co-Director, MPH concentration in Social and Behavioral Sciences in Public Health; Associate Director, Center for Qualitative...

Noreen Hynes, MD MPH

Director, Geographic Medicine Center of the Division of Infectious Diseases

Stefan Baral, MD MPH,MBA,MSc

Director, Key Populations Program

Robert Bollinger Jr., MD MPH

Director, Johns Hopkins Center for Clinical Global Health Education (CCGHE); Associate Director, Johns Hopkins Center for Global...

Yukari C. Manabe, MD

Associate Director of Global Health Research and Innovation

August 2019



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