Modern science takes into account phenotype complexity and establishes approaches to track changes on every possible level. Many "omics" studies have been developed over the last decade. Metabolomic analysis enables dynamic measurement of the metabolic response of a living system to a variety of stimuli or genetic modifications. Important targets of metabolomics is biomarker development and translation to the clinic for personalized diagnosis and a greater understanding of disease pathogenesis. The current review highlights the major aspects of metabolomic analysis and its applications for the identification of relevant predictive, diagnostic and prognostic biomarkers for some ocular diseases including dry eye, keratoconus, retinal diseases, macular degeneration, and glaucoma. To date, possible biomarker candidates for dry eye disease are lipid metabolites and androgens, for keratoconus cytokeratins, urea, citrate cycle, and oxidative stress metabolites. Palmitoylcarnitine, sphingolipids, vitamin D related metabolites, and steroid precursors may be used for distinguishing glaucoma patients from healthy controls. Dysregulation of amino acid and carnitine metabolism is critical in the development and progression of diabetic retinopathy. Further work is needed to discover and validate metabolic biomarkers as a powerful tool for understanding the molecular mechanisms of ocular diseases, to provide knowledge on their etiology and pathophysiology and opportunities for personalized clinical intervention at an early stage.

In vivo confocal microscopy is a useful tool for evaluating the corneal microstructure when a Kayser-Fleischer ring is clinically present. The ring consists of granular, bright particles that increase in density toward Descemet's membrane, and is associated with a decreased number of keratocytes and peculiar dark, round areas in all stromal layers, probably a sign of corneal damage. When the ring is not visible in subjects with Wilson's disease, changes to the corneal microstructure are insignificant.

Purpose: The purpose of this study was to determine the presence of dry eye disease and possible treatment options in patients with obstructive sleep apnea and continuous positive airway pressure. Materials and methods: A total of 72 patients (midlife age) with obstructive sleep apnea and continuous positive airway pressure therapy underwent a comprehensive eye examination. Fluorescein staining of the anterior ocular surface and tear break-up test were performed. All of the patients who were diagnosed with dry eye disease received personalized therapy. One month later, re-examination was performed using the same methodology and clinical settings. Results: On the first examination, 48 of 72 patients (66.67%) were diagnosed with dry eye disease. Floppy eyelid syndrome was reported in 26 patients (54.17%) with dry eye disease. The treatment of 40 patients included artificial tear supplements during the day in combination with high-viscosity topical gels before bedtime. In more severe cases (10.42% of all participants), the application of bandage contact lenses for 3 months was necessary. Because of excessive lid laxity, surgical reconstruction of the eyelids was performed in three patients (6.25%). Conclusions: A multidisciplinary approach is essential for obstructive sleep apnea. Practitioners from different specialties must be well acquainted with risk factors, signs, and symptoms. The early detection of dry eye disease in patients with obstructive sleep apnea and appropriate treatments are important for improving the quality of life in this patient group.

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