Hamidreza Heidari

Biography

I have completed my master's degree in Optometry at Iran University of Medical Sciences (IUMS). Taking some graduate and undergraduate courses including Ocular Pathology, Cornea and Contact lenses, and Advance Optometry, and working with two research centers of Mashhad and Tehran, resulted in publication of peer-reviewed journal articles successfully.
My interest in the field of ocular surface especially corneal biomechanics stems from my desire to realize the effect of biomechanical properties of the cornea on different ocular diseases and interventions including refractive surgeries in order to anticipate the results for better outcome measures and satisfaction for patients.
During my master's thesis, I conducted my studies on corneal biomechanics of Corneal Granular Dystrophy (GCD) patients compared to normal subjects. Using my best endeavors during this time, I have published a paper in "Journal of Clinical Medicine" (Changes in Stress-Strain Index and Corneal Biomechanics in Granular Corneal Dystrophy). My aim in the paper was to investigate the difference of biomechanical features of GCD with newly available Stress-Stain-Index and Dynamic Response parameter of Corvis ST for the first time. During my master's degree I have the opportunity to work on different clinical trials of dry eye disease.
Currently, I am working on Impact of Nutrition on Ocular Surface.

Research Title

Nutrition and Its Impact on Dry Eye Disease

Supervisors

Maria Markoulli, Jayashree Arcot, Jerome Ozkan

Research Abstract

Dry eye disease (DED) is a multifactorial disease of the ocular surface that impacts a vast number of individuals worldwide, rendering it amongst the most prevailing reasons for patient visits to eye care practitioners. A vicious cycle of tear film instability and hyperosmolarity, which increases ocular surface inflammation, damage, and neurosensory abnormalities, characterizes this symptomatic condition. Significant discomfort, difficulties doing everyday tasks, decreased vitality, poor general health, and frequently depression are all symptoms of moderate to severe DED. Aqueous deficient dry eye (ADDE) and evaporative dry eye (EDE) are the two known types of DED. When lacrimal secretion is decreased in ADDE under circumstances of normal evaporation from the eye, tears become hyperosmolar. When there is a healthy lacrimal gland present, excessive evaporation from the exposed tear film contributes to tear hyperosmolarity in EDE. Tear hyperosmolarity results from evaporation from the ocular surface and, in that sense, all forms of DED are evaporative. Tear osmolarity is a function of tear evaporation in either ADDE or EDE. EDE is therefore better understood as a hyper-evaporative state.
The role of nutrition in the prevention and treatment of DED has been undervalued. A, B12, C, and D are the main vitamins linked to ocular surface diseases. Recent in vivo research including both humans and animals has demonstrated that vitamin D undergoes active metabolism in the human cornea due to the presence of 1-alphahydroxylase, a crucial enzyme that converts vitamin D3 to calcitriol, its most active form. The pathophysiology of dry eye disease, particularly conjunctival squamous metaplasia and a loss of conjunctival goblet cells, has been linked to vitamin D insufficiency.
It is important while trying to understand the effect of vitamins and the vicious cycle that happens in the ocular surface that is associated with DED, to try first to characterize and prevent it, utilizing the proper methodologies and supplements with randomized controlled clinical studies.
The aim of this PhD is to increase our knowledge and understanding of the role of Vitamin D consumption on the corneal health and DED. These findings may in the future guide the development of novel treatment strategies for severe and chronic forms of DED.