In Vivo Confocal Microscopy in Chloroquine-Induced Keratopathy
A 64-year-old Caucasian female was referred by her rheumatologist. She had a medical history of fybromyalgia that had been diagnosed in December 2008. In November 2009 the patient began treatment with a daily dose of 250 mg of chloroquine bisphosphonate (Clorochina, Bayer Italia, Milano, Italy) for 9 months. The only ocular symptom was modest dry eye that was controlled with artificial tears.\nAt presentation, the fybromialgia was well controlled. The only significant findings on slit-lamp biomicroscopy were corneal deposits and vortex keratopathy (cornea verticillata) []. Uncorrected visual acuity was 0.0 LogMAR in the right eye and 0.0 LogMAR in the left eye. Intraocular pressure (IOP) was 13 mm Hg bilaterally and the fundus examination was unremarkable. The patient was examined using a scanning slit corneal confocal white-light microscopy Confoscan 4 (Nidek Co. Ltd., Gamagori, Japan), with a ×40 lens. Confoscan 4 was used to study the corneal morphology and assess layer reflectivity and cellular density.\nThe main parameters for the acquisition sequence were set with a z-axis range of movement of 1000 μm, thus giving a theoretical z-axis distance between images in the scans of 10 μm. Each frame is approximately 400×300 μm (area, 0.12 mm2). The position on the z-axis of the corneal thickness of each image was obtained using the Z-Scan function of the instrument. The Z-Scan is a graph that plots the depth (expressed in microns) on the x-axis and the level of reflectivity (expressed in arbitrary numerical units called light reflectance units, LRU) on the y-axis, of each corneal image included in the scan.\nOxibuprocaine cloridrate 0.4% was instilled in each eye (Novesina 0, 4%, Novartis Farma, Origgio, Italy), than a drop of polyacrylic acid 0.2% (Viscotirs gel, Medivis, Catania, Italy) was placed on the microscope probe as a coupling agent to avoid epithelial damage.