Assessment of dry eye in a GVHD murine model: Approximation through tear osmolarity measurement.

Dry eye disease is one of the most frequent pathological events that take place in the course of the graft versus host disease (GVHD), and is the main cause of deterioration in quality of life for patients. Thus, demonstration of dry eye signs in murine models of oGVHD is crucial for the validation of these models for the study of the disease. Given the increasing evidence that tear osmolarity is an important player of dry eye disease, our purpose in this study was to validate the use of a reliable method to assess tear osmolarity in mice: the electrical impedance method. Then, we wanted to test its utility with an oGVHD model. Tear volume assessment was also performed, using the phenol red thread test. We found differences in tear osmolarity in mice that received a transplant with cells from bone marrow and spleen (the GVHD group) when compared with mice that only received bone marrow cells (the BM group) at day 7 (362 ± 8 mOsm/l and 345 ± 9 mOsm/l respectively; P < 0.01) and day 21 (348 ± 19 mOsm/l vs. 326 ± 15 mOsm/l; P < 0.05). We found also differences in tear volume at day 14 (2.30 ± 0.61 mm in oGVHD group and 2.89 ± 0.62 mm in BM group; P = 0.06) and at day 21 (2.10 ± 0.30 mm in oGVHD group and 2.89 ± 0.32 mm in BM group; P < 0.01). Besides this, we observed reduction in epithelial thickness between the GVHD and BM groups (37.0 ± 6.2 µm and 43.6 ± 3.3 µm respectively; P < 0.05). These data show the usefulness of the electrical impedance method to measure tear osmolarity in mice. We can also conclude that this oGVHD model mimics the tear film alterations found in human dry eye disease, what contributes to give relevance to this model for the study of GVHD.

Atypical posterior scleritis mimicking an amelanotic choroidal melanoma. A case report.

Purpose: To describe a clinical case of atypical posterior scleritis mimicking an amelanotic choroidal melanoma. Method: Observational case report of a 54-year-old woman who presented to the emergency department with photophobia and blurred vision in her left eye for three days. The development of a raised hypopigmented lesion superior to the papilla with choroidal folds and without vitritis simulated an amelanotic choroidal melanoma. Differential diagnosis took into consideration other compatible entities, including choroidal masses or orbital pseudotumor. Results: The patient was subject to full clinical examination, laboratory test, optical coherence tomography, orbital echography, and magnetic resonance imaging. Treatment with oral prednisone showed a significant improvement in all clinical and anatomical parameters. Discussions: Posterior scleritis is characterized by great clinical variability and sometimes can simulate an amelanotic choroidal melanoma. Performing an appropriate differential diagnosis of a large amelanotic lesion is the most important point during a routine ocular examination due to the implications for the patient. Conclusions: Posterior scleritis is a rare and incompletely understood inflammatory disease that affects the posterior part of the sclera. It can be associated with a range of conditions and very often is underdiagnosed. In about one third of the cases, it is related to some systemic disease, especially to autoimmune entity, so it may require a multidisciplinary approach. This case highlighted the importance of a solid differential diagnosis and an early treatment in order to help prevent the appearance of complications that can limit not only the visual outcome of the patient but even his survival in the most extreme cases. Abbreviations: LE = left eye; RE = right eye; BCVA = best corrected visual acuity; BO = both eyes; IOP = intraocular pressure; OCT = optical coherence tomography; MRI = Magnetic Resonance Imaging.