Infrared analysis in the aqueous humor of patients with uveitis: Preliminary results.

Inflammatory processes affecting the uvea result in a temporary o permanent blurred vision and represent an important cause of visual impairment worldwide. It is often hard to make a precise diagnosis which is dependent on the clinical expertise, diagnostic tests, laboratory investigations in blood and sometimes in the aqueous humor (AH). With the aim of obtaining proof of principle Fourier Transformed Infrared (FT-IR) absorbance spectroscopy was applied to study the molecular composition of 72 AH samples collected in 26 patients with uveitis and in 44 controls. The unsupervised exploration of the internal structure of the dataset by principal component analysis reduced hundreds IR variables to those most representative allowing to obtain the predictive model that distinguished the AH spectra of patients with uveitis from controls. The same result was obtained by unsupervised agglomerative cluster analysis. After labeling the spectra with some clinical information it was observed that most severe uveitis with active processes were grouped separately from chronic and relapsing uveitis and controls. The consistence of prediction models is discussed in the light of supporting etiological diagnosis by machine learning processes. In conclusion, proof of principle has been obtained that the IR spectral pattern of AH may reflect particular uveal diseases.

SD-OCT Choroidal Thickness in Advanced Primary Open-Angle Glaucoma.

PURPOSE: To assess the choroidal thickness in advanced primary open-angle glaucoma (POAG) comparing patients affected by advanced glaucoma and normal subject using spectral domain optical coherence tomography (SD-OCT). METHODS: In total, 35 eyes of 35 patients affected by POAG with advanced perimetric defect (mean deviation worse than -12 dB) were prospectively enrolled and underwent a complete ophthalmologic examination, including enhanced depth imaging SD-OCT. One eye of 35 healthy subjects served as control group. Choroidal thickness was measured at the subfoveal location, at 0.5, 1.0, and 2.0 mm nasal and temporal to the fovea. Primary outcome measure was the identification of different choroidal thickness between advanced glaucoma patients and normal subjects. RESULTS: Glaucoma and control group were homogenous for age, sex, and axial length (P>0.05 in all cases). A significant difference was found in the subfoveal choroidal thickness (SFCT) adjusted for age and axial length between glaucoma and control eyes (P=0.042); in glaucoma patients the mean adjusted SFCT was 209.90 µm compared with 234.78 µm in control subjects. Both temporal and nasal choroidal thickness measurements followed the same SFCT trend, even if only temporal ones were statistically significant. We also found that SFCT decreased with age and increased axial length (P=0.007 and 0.001, respectively). Sex and intraocular pressure did not significantly influence the choroidal thickness (P=0.87 and 0.35, respectively). CONCLUSIONS: Patients affected by advanced POAG damage have a thinner choroidal thickness compared with normal subjects, using SD-OCT. We also confirmed that age and axial length were the main factors affecting choroidal thickness in these patients.