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Purpose: to evaluate the morphological changes in eye tissue after the influence of high‐frequency electric current welding (HFECW) with suprachoroidal approach in rabbit's eyes in order to induce chorio‐retinal adhesion as an alternative treatment for retinal tears. Methods: 54 adult rabbits were used. The study complied to the ARVO statement for use of animals in ophthalmic and visual research. In the treated group, the retina was coagulated 7–10 mm from the limbus through a U‐shaped scleral incision with suprachoroidal approach using 23‐gauge tip and modified HFECW generator EK‐300 M1 (E.O. Paton Electric Welding Institute, Kyiv, Ukraine) with parameters: 66 kHz HFECW, three modes of 10–12 Volts (V), 12–14 V and 14–16 V. The eyes were then enucleated after 1 hour and 3‐, 7‐, 14‐ and 30‐days. Tissue changes were analysed using haematoxylin–eosin staining and light microscopy, and compared to the control eyes. Results: In all treated eyes the monopolar HFECW induced an increased tissue adhesion in the area of electrode application, which strengthened with time. The retina responded by apparent destruction of rods, cones, loss of bipolar, amacrine, horizontal and ganglion cells, development of cysts and migration of RPEs. The choroid showed damage and migration of melanocytes. By 30 days, a ​​tissue thinning with partial cell regeneration and connective tissue degeneration were apparent. Amplification of the voltage from 10 to 16 V caused a shift from active exudation without significant tissue damage to acute retinal necrosis, respectively. The nearby lying retinal layers and vitreous remained intact. Conclusions: Application of HFECW with suprachoroidal approach induced chorio‐retinal adhesion in 1 hour after the treatment, which strengthened within first weeks after the surgery. Implementation of HFECW as an alternative method to treat retinal tears in eyes with retinal detachment could reduce the need for endotamponade and the risks of its possible complications.

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A comparison of the cellular content of needle tip aspirates and entry sites after transcon-junctival intravitreal injection (IVI) using different needle types was performed. White out-bred rats and human cadaver eyes were used for IVI by hypodermic 27 gauge (G) and 30G needles, and spinal anesthesia Pencan 27G needles. Aspiration of vitreous for quantitative morphological and cell cultivation analysis, as well as cyto-histological analysis of aspirates and entry sites were carried out. The most common cells in the aspirates from all needle types were conjunctival epithelial-, ciliary body non-pigmented epithelial-and sclerocyte-like cells and granular proteins. Crystallized vitreous specimens were present in each aspirate. The entry sites of hypodermic needles showed marked trauma in all wall layers of rat and human eyes accompanied by cellular destruction and hemorrhages. Pencan 27G needle caused less tissue trauma with partial reposition of sclerocytes. Transconjunctival IVIs with hypodermic 27G and 30G, and Pencan 27G needles result in trauma of all layers of the eyeball. The possible consequences of cellular content being cut and injected into the eye, as well as the entry site wound shape deserve future consideration and improvements.