Freeze-controlled Crystallisation of the Aqueous Humour in Glaucomatous and Non-glaucomatous Patients
The purpose of this study was to investigate the aqueous humour of glaucomatous and non-glaucomatous patients by freeze-controlled crystallisation qualitatively to detect a possible difference. Aqueous humour was taken from 20 patients with different kinds of glaucoma (11 primary open-angle glaucoma, eight pseudo-exfoliation glaucoma, one pigmentary glaucoma) and compared with samples from 40 patients with cataracts and to samples from seven patients with cataract and glaucoma; 1μl of each sample was applied to a microscope slide and put in a deep-freezer at a constant temperature of -20°C for 24 hours. During this time, the water evaporated and distinct crystal patterns developed. These patterns were examined stereo-microscopically, stored digitally and compared with each other. Many distinct crystals of different sizes and formations were obtained. No obvious differences in the crystal patterns could be found between the three groups (patients with glaucoma, cataract or cataract and glaucoma). As a multifactorial disease, open-angle glaucoma is characterised by specific changes to the trabecular meshwork cells with an accumulation of deposits of extracellular matrix. Since the trabeculum is rinsed consistently by aqueous humour, changes of the compounds might influence these cells. Alterations concerning this were published. In contrast to the ferning test, one of several methods of examining fluids with patterns that are highly dependent on temperature and humidity, our examinations with freeze-controlled crystallisation at a constant and controlled temperature of – 20°C gave more valid results. In our study we could not find obvious differences in the crystal patterns of patients with cataract, glaucoma or cataract and glaucoma.