The impact of corticosteroid therapy on the bacterial corneal ulcer healing process

Purpose: to conduct a clinical and morphological study of the role of corticosteroids in the healing of the ulcerative defect on an experimental model of the bacterial corneal ulcer.Material  and methods. The developed model of the bacterial corneal ulcer was used. Rabbits with bacterial corneal ulcer were divided into 4 groups of 10 animals (10 eyes) each. Group 1 received local antibacterial treatment. Groups 2 and 3 additionally  received injections of 0.2–0.3 ml of Dexamethasone 0.1 % solution once per day (parabulbarly  or under the skin of the back,  respectively). Group 4 received no treatment but was checked  clinically after ulcer modeling. Structural changes in eye tissues were assessed by histopathological examination  using an examination  on a Leica microscope system with a magnification of 100 to 600.Results. Addition of corticosteroids in the early period of bacteria ulcer treatment contributes to an inhibition of the inflammatory process, reduces the action of collagenolysis processes and the size of the ulcer defect, and suppresses angiogenesis, which leads to an improvement in scar tissue quality.Conclusion. Topical parabulbar injections of corticosteroids adding to the treatment topically in the form of parabulbar injections of corticosteroids contributes to changes in the emerging fibrous tissue which fills the ulcerous defect: a thin scar is formed, which is optically useful

Treatment of corneal ulcers by local ultraviolet crosslinking (an experimental study)

Purpose: to compare the effectiveness of corneal ulcer treatment by antibiotic therapy and local ultraviolet crosslinking in a clinical and morphological experimental study using the new Crosscor device. Material and methods. The study was performed on 15 rabbits (30 eyes) with a model of corneal ulceration caused by Staphylococcus aureus. Rabbits were divided into 3 groups of 5 specimens each (10 eyes). Group 1 received local ultraviolet A range (UVA) crosslinking (CL) of the cornea using the Crosscor device (3 procedures lasting 5, 6 and 6 minutes each were given with intervals of three days). In group 2, CL was combined with antibacterial treatment (AB): instillations of tobramycin 0.3 % and ofloxacin ointment 3 mg / g were given 4 times a day for 14 days. In the control group, only AB treatment was given. The dynamics of inflammation, the intensity of turbidity and the size of the corneal ulcer were evaluated using biomicroscopy, fluorescein test, photoregistration of the anterior part of the eye, and according to a point system. Morphological changes in the cornea were determined using light microscopy (Leica with a DFC 420C digital camera). Results. In group 1 (CL) complete healing of the ulcer defect was noted on the 9th day of observation; in group 2 (CL + AB), the diameter of the corneal ulcer was reduced to 1.6 ± 0.5 mm, in the control group (AB) it was reduced to 1.9 ± 0.3 mm (p < 0.05). The total score of inflammatory changes on day 9 in the 1st group was 0.8 ± 1.3, in the 2nd group, 3.6 ± 0.8, and in the control group, 3.7 ± 0.4 (p < 0.05). On day 9, in all cases of the 1st group, a slight clouding of the cornea was formed (0–-1 point); in the 2nd group and in the control group in 90 % of cases a rough clouding of the cornea with vascularization was formed (3 points). Morphological examination of the eyes showed that only in the 1st group avascular scars with an ordered arrangement of fibrous tissue fibrils were formed. Conclusion. The data obtained indicate a significantly higher efficiency of corneal ulcer treatment by local UVA crosslinking using Crosscor as compared with antibiotic therapy