The aim of this study was to find out to which extent the instilled silicone oil affects the changes of lens, cornea, and the ocular pressure with regard to its time kept in the operated eye with a lens. The study was carried out on the sample of 40 patients, divided in three groups. The first group of patients with the silicone oil kept in the eye during 3 months, the second one during 3-6 months, and the third one during 6-9 months. Statistically important changes were observed in the progression of the lens opacification with the patients, progressively with the time of keeping the silicone oil in the eye. The followed cornea opacifications and increased ocular pressure were not statistically significantly linked with the length of keeping the silicone oil in the eye, so that it can be concluded that the silicone oil is the best substitute for the vitreous body but it should be removed from the eye, most frequently, in the period of 3-6 months from the date of its instillation, and after 3 weeks at the earliest.