Dimensions of the ciliary muscles of Brücke, Müller and Iwanoff and their associations with axial length and glaucoma.

BACKGROUND: To assess the dimensions of Brücke's muscle, as the longitudinal portion, and of Müller's muscle and Iwanoff's muscle combined as circular and radial/reticular portions of the ciliary muscle. METHODS: The histomorphometric study included human globes that had been enucleated due to an ocular tumor or end-stage glaucoma. After immunohistochemical staining of the ciliary muscles, the histology slides were examined under a light microscope applying a digitized image analysis system. RESULTS: The study included 55 globes [axial length 25.6 ± 3.0 mm (range 21.0 mm-36.0 mm)] from 55 patients [mean age, 33.7 ± 18.3 years (range:1-66 years)]. Length of Brücke's muscle (mean 3.40 ± 0.76 mm) increased with longer axial length (P < 0.001; regression coefficient beta: 0.52) and was not significantly associated with age (P = 0.12), presence of glaucoma (P = 0.11) or Brücke's muscle thickness at the scleral spur (P = 0.32), at the site of the maximum thickness of the ciliary body (P = 0.84) or at the posterior end of Müller's/Iwanoff's muscle (P = 0.66), or with thickness (P = 0.29) and cross-sectional area (P = 0.85) of Müller's/Iwanoff's muscle. Mean distance between Brücke's muscle end and the ora serrata measured 1.73 ± 1.13 mm and increased with longer axial length (P < 0.001; beta: 0.46). Distance from the scleral spur to the ora serrata (mean: 4.94 ± 1.42 mm; range: 3.08-9.09 mm) increased with longer axial length (P < 0.001; beta: 0.61). Maximal thickness (mean: 245 ± 125 µm) and cross-section area (mean: 0.19 ± 0.11 mm2) of Müller's/Iwanoff's muscle decreased significantly with the diagnosis of glaucoma (P = 0.02;beta:-0.38) and longer axial length (P = 0.03; beta: -0.35). CONCLUSIONS: Length of Brücke's muscle increased with axial length of the globe, while its cross-sectional area was independent of axial length. Müller's/Iwanoff's muscle decreased in cross-sectional area with longer axis, and in particular with the presence of glaucoma, while the dimensions of Brücke's muscle were not related to glaucoma.

Bruch´s membrane thickness in relationship to axial length.

PURPOSE: To assess a potential role of Bruch´s membrane (BM) in the biomechanics of the eye, we measured its thickness and the density of retinal pigment epithelium (RPE) cells in various ocular regions in eyes of varying axial length. METHODS: Human globes, enucleated because of an ocular tumor or end-stage glaucoma were prepared for histological examination. Using light microscopy, the histological slides were histomorphometrically examined applying a digitized image analysis system. RESULTS: The study included 104 eyes with a mean axial length of 27.9±3.2 mm (range:22.6mm-36.5mm). In eyes without congenital glaucoma, BM was significantly thickest (P<0.001) at the ora serrata, followed by the posterior pole, the midpoint between equator and posterior pole (MBEPP), and finally the equator. BM thickness was not significantly correlated with axial length (ora serrata: P = 0.93; equator:P = 0.31; MBEPP:P = 0.15; posterior pole:P = 0.35). RPE cell density in the pre-equatorial region (P = 0.02; regression coefficient r = -0.24) and in the retro-equatorial region (P = 0.03; r = -0.22) decreased with longer axial length, while RPE cell density at the ora serrata (P = 0.35), the MBEPP (P = 0.06; r = -0.19) and the posterior pole (P = 0.38) was not significantly correlated with axial length. Highly myopic eyes with congenital glaucoma showed a tendency towards lower BM thickness and lower RPE cell density at all locations. CONCLUSIONS: BM thickness, in contrast to scleral and choroidal thickness, was independent of axial length in eyes without congenital glaucoma. In association with an axial elongation associated decrease in the RPE cell density in the midperiphery, the findings support the notion of a biomechanical role BM may play in the process of emmetropization/myopization.

Clinical and histopathological features of adenomas of the ciliary pigment epithelium.

PURPOSE: Adenomas of the ciliary pigment epithelium (CPE) are rare benign tumours which have mainly to be differentiated from malignant ciliary body melanomas. Here we report on a consecutive series of patients with CPE adenomas and describe their characteristics. METHODS: The retrospective hospital-based case series study included all patients who were consecutively operated for CPE adenomas. RESULTS: Of the 110 patients treated for ciliary body tumours, five patients (4.5%) had a CPE adenoma. Mean age was 59.0 ± 9.9 years (range: 46-72 years). Mean tumour apical thickness was 6.6 ± 1.7 mm. Tumour colour was mostly homogenously brown to black, and the tumour surface was smooth. The tumour masses pushed the iris tissue forward without infiltrating iris or anterior chamber angle. Sonography revealed an irregular echogram with sharp lesion borders and signs of blood flow in Color Doppler flow imaging. Ultrasonographic biomicroscopy demonstrated medium-low internal reflectivity and acoustic attenuation. In magnetic resonance imaging (MRI), the tumours as compared to brain were hyperintense on T1-weighted images and hypointense on T2-weighted images. Tumour tissue consisted of cords and nests of pigment epithelium cells separated by septa of vascularized fibrous connective tissue, leading to a pseudo-glandular appearance. The melanin granules in the cytoplasm were large and mostly spherical in shape. In four patients, the tumours were hyperpigmented. Tumour cells were large with round or oval nuclei and clearly detectable nucleoli. CONCLUSIONS: These clinical characteristics of CPE adenomas, such as homogenous dark brown colour, smooth surface, iris dislocation and anterior chamber angle narrowing but no iris infiltration, segmental cataract, pigment dispersion, and, as compared to brain tissue, hypointensity and, as compared to extraocular muscles or lacrimal gland, hyperintensity on T2-weighted MRI images, may be helpful for the differentiation from ciliary body malignant melanomas.