Features of Tissue Reaction in the Tenon Capsule in Progressive Myopia

Background: Research actuality is determined by the first, the prevalence of refraction errors including progressive myopia among children secondly, high risk and tends to develop complications from the visual organ in refractive disorders.

Aims: To investigate tissue reactions occurring in the Tenon’s capsule with anomalies of refraction, including with progressive myopia.

Materials and methods: A one-step study of the Tenon’s capsule of 47 samples (25 with hyperopia and 22 with progressive myopia) was carried out. The material of the Tenon’s capsule was obtained during surgical treatment of strabismus and sclera strengthening operations with progressive myopia. The Tenon’s capsule was studied at different levels: tissue, cellular, subcellular. Fragments of Tenon’s capsule were stained with hematoxylin-eosin and picrofuchsin mixture by the method of van Gieson at the tissue level. This allowed obtaining a general picture of the morphology of Tenon’s capsule. Fragments of Tenon’s capsule were stained by toluidine blue in tetraborate sodium at the cellular level. This gave the opportunity to define the scope for ultratome and spend morphometry of cellular composition. A fragment of Tenon’s capsule was studied by transmission electron microscopy (TEM) at the subcellular level and was performed ultrastructural morphometry of fibroblasts, evaluation of the density of the collagen fibers.

Results: Were evaluated by qualitative and quantitative characteristics of the structure of Tenon’s capsule with two anomalies of refractions: progressive myopia and hyperopia: with progressive myopia in Tenon’s capsule, in contrast to hyperopia, the following number of fibroblasts (1.56±0.12 per 10⁴ µm²), mast cells (0.08±0.0² per 10⁴ µm2), adipocytes (0.01±0.001 per 10⁴ µm²) were observed; ultrastructural features of fibroblasts were represented by such quantitative characteristics: the area of the fibroblast nucleus was 1.60±0.82 in µm², the length of the karyolemma was 6.99±0.189 µm, the number of nucleoli was 0.17±0.015 per 1 µm², the number of mitochondria and lysosome -2.05±0.14 per 1 µm2; 0.64±0.08 per 1 µm², respectively); the density of collagen fiber was 28.72±4.18%, fibrillar fibrillation and fragmentation were recorded.

Conclusions: Hyperplasia of fibroblasts and their ultrastructures, mast cells, reduction in the level of adipocytes and the density of collagen fibrils ― these changes are features of the tissue reaction in the tenon capsule and reflect the adaptive nature of the processes occurring during progressive myopia.