Tear 1H Nuclear Magnetic Resonance-Based Metabolomics Application to the Molecular Diagnosis of Aqueous Tear Deficiency and Meibomian Gland Dysfunction.

PURPOSE: Meibomian gland dysfunction (MGD) is a major cause of signs and symptoms related to dry eyes (DE) and eyelid inflammation. We investigated the composition of human tears by metabolomic approaches in patients with aqueous tear deficiency and MGD. METHODS: Participants in this prospective, case-control pilot study were split into patients with aqueous tear deficiency and MGD (DE-MGD [n = 15]) and healthy controls (CG; n = 20). Personal interviews, ocular surface disease index (OSDI), and ophthalmic examinations were performed. Reflex tears collected by capillarity were processed to 1H nuclear magnetic resonance (NMR) spectroscopy and quantitative data analysis to identify molecules by spectra comparison to library entries of purified standards and/or unknown entities. Statistical analyses were made by the SPSS 22.0 program. RESULTS: Chemometric analysis and 1H NMR spectra comparison revealed the presence of 60 metabolites in tears. Differentiating features were evident in the NMR spectra of the 2 clinical groups, characterized by significant upregulation of phenylalanine, glycerol, and isoleucine, and downregulation of glycoproteins, leucine, and -CH3 lipids, as compared to the CG. The 1H NMR metabolomic analyses of human tears confirmed the applicability of this platform with high predictive accuracy/reliability. CONCLUSIONS: Our key distinctive findings support that DE-MGD induces tear metabolomics profile changes. Metabolites contributing to a higher separation from the CG can presumably be used, in the foreseeable future, as DE-MGD biomarkers for better managing the diagnosis and therapy of this disease.

Nonorganic visual loss and associated psychopathology in children.

PURPOSE: To report the frequency of nonorganic visual loss (NOVL) and associated psychopathology in children. METHODS: A total of 973 children were examined in our ophthalmology practice between 2006 and 2009. Basic ophthalmologic exploration (visual acuity, stereopsis, cycloplegic refraction, ocular motility, pupil dynamics, biomicroscopy, indirect ophthalmoscopy) and specific tests for NOVL diagnosis were performed (confusion with lenses test, mirrors test, Roth test, Bravais test). We also investigated the psychosocial situation and associated psychiatric problems. RESULTS: Thirty children were diagnosed with NOVL. The mean age of the children was 8.93 years (± 2.61); 70% were girls. September was the commonest month of presentation (26.7%) and unilateral (3.3%) or bilateral (80%) visual loss was the most frequent symptom (83.3% in total). In 20% of cases we detected psychosocial anomaly and 40% were seeking to wear glasses. CONCLUSIONS: Malingering in children is very frequent. We can make the diagnosis with simple tests. It is not necessary to perform imaging and electrophysiologic testing, thus avoiding unnecessary examinations as well as absenteeism from work for parents and health care costs.

[Simulation in ophthalmology]. / Simulación en oftalmología.

CLINICAL CASES: Four cases of patients simulating eye problems are reported. The patients included: an adopted 9 year-old girl complaining of bilateral visual loss, a 10 year-old girl with school and family problems complaining of decreased visual acuity, a 22 year-old female mentioning unilateral visual loss after a car accident, and a 30 year-old female complaining of decreased visual acuity after refractive surgery. Structural and functional tests were performed on all 4 patients and none of the tests revealed any pathological findings. The 4 cases were diagnosed as patients simulating ophthalmological symptoms. DISCUSSION: A non-organic cause of visual loss is a common problem in Ophthalmology. Simulation is the diagnosis used when an adult consciously tries to obtain some kind of benefit without proven pathology. In the case of children, obtaining benefit is not their intention, but psycho-social and psychiatric problems are frequently associated in these cases.