Background: To investigate the effect of sirolimus (SRL) eye drops on acute alkali-burn-induced corneal neovascularization (CNV) and explore its possible mechanism.

Methods: A total of 57 male Sprague-Dawley rats weighing 160–180 g were randomly divided into four groups including a normal control group (NC group, n=12), an untreated alkali-burned model control group (MC group, n=15), a blank eye drop treatment group (BT group, n=15), and an SRL eye drop treatment group (ST group, n=15). Corneal inflammation and CNV were observed and scored under a slit-lamp microscope 3, 7, and 14 days after alkali exposure. Three rats were randomly sacrificed in each group before modeling and 3, 7, 14 days after modeling, and the corneas of right eyes were harvested for Western blotting to compare the expression levels of VEGFR2 and caspase-3.

Results: Corneal inflammation scoring showed that the corneal edema and conjunctival congestion were severe in the MC, BT, and ST groups 1 day after alkali exposure but were alleviated at day 3. The corneal transparency was significantly higher in the ST group than in the MC and BT groups at days 7 (F=9.77, P<0.05) and 14 (F=5.81, P<0.05). At day 1, the corneal limbal vascular network was markedly filled. SNV was obvious at days 3, 7, and 14. The new blood vessels were shorter and sparser in the ST group than in the MC and BT groups, and the CNV scores showed significant differences among these groups (day 3: F=8.60, P<0.05; day 7: F=11.40, P<0.05; and day 14: F=41.59, P<0.01). Western blotting showed that the expressions of VEGFR2 and caspase-3 were low before modeling and showed no significant difference among the different groups (F=0.52, P>0.05; F=0.98, P>0.05). The corneal expression of VEGFR2 became significantly higher in the MC and BT groups than in the ST group 3, 7, and 14 days after alkali exposure, and there were significant differences in relative gray-scale values among these groups (day 3: F=32.16, P<0.01; day 7: F=85.96, P<0.01; day 14: F=57.68, P<0.01). The increase in the corneal expression of caspase-3 was significantly larger in the ST group than in the MC and BT groups at days 3, 7, and 14, and there were significant differences in relative gray-scale values among groups (day 3: F=32.16, P<0.01; day 7: F=53.02, P<0.01; day 14: F=38.67, P<0.01).

Conclusions: SRL eye drops can alleviate acute alkali-burn-induced corneal inflammation and inhibit alkali-burn-induced CNV in rat models. It can reduce VEGFR2 expression and increase caspase-3 expression in the corneal tissue, which may contribute to the inhibition of alkali-burn-induced CNV.

Background: To investigate the effect of sirolimus (SRL) eye drops on acute alkali-burn-induced corneal neovascularization (CNV) and explore its possible mechanism.

Methods: A total of 57 male Sprague-Dawley rats weighing 160–180 g were randomly divided into four groups including a normal control group (NC group, n=12), an untreated alkali-burned model control group (MC group, n=15), a blank eye drop treatment group (BT group, n=15), and an SRL eye drop treatment group (ST group, n=15). Corneal inflammation and CNV were observed and scored under a slit-lamp microscope 3, 7, and 14 days after alkali exposure. Three rats were randomly sacrificed in each group before modeling and 3, 7, 14 days after modeling, and the corneas of right eyes were harvested for Western blotting to compare the expression levels of VEGFR2 and caspase-3.

Results: Corneal inflammation scoring showed that the corneal edema and conjunctival congestion were severe in the MC, BT, and ST groups 1 day after alkali exposure but were alleviated at day 3. The corneal transparency was significantly higher in the ST group than in the MC and BT groups at days 7 (F=9.77, P<0.05) and 14 (F=5.81, P<0.05). At day 1, the corneal limbal vascular network was markedly filled. SNV was obvious at days 3, 7, and 14. The new blood vessels were shorter and sparser in the ST group than in the MC and BT groups, and the CNV scores showed significant differences among these groups (day 3: F=8.60, P<0.05; day 7: F=11.40, P<0.05; and day 14: F=41.59, P<0.01). Western blotting showed that the expressions of VEGFR2 and caspase-3 were low before modeling and showed no significant difference among the different groups (F=0.52, P>0.05; F=0.98, P>0.05). The corneal expression of VEGFR2 became significantly higher in the MC and BT groups than in the ST group 3, 7, and 14 days after alkali exposure, and there were significant differences in relative gray-scale values among these groups (day 3: F=32.16, P<0.01; day 7: F=85.96, P<0.01; day 14: F=57.68, P<0.01). The increase in the corneal expression of caspase-3 was significantly larger in the ST group than in the MC and BT groups at days 3, 7, and 14, and there were significant differences in relative gray-scale values among groups (day 3: F=32.16, P<0.01; day 7: F=53.02, P<0.01; day 14: F=38.67, P<0.01).

Conclusions: SRL eye drops can alleviate acute alkali-burn-induced corneal inflammation and inhibit alkali-burn-induced CNV in rat models. It can reduce VEGFR2 expression and increase caspase-3 expression in the corneal tissue, which may contribute to the inhibition of alkali-burn-induced CNV.

Abstract: The efficacy of selective laser trabeculoplasty (SLT) to treat open-angle glaucoma (OAG) and ocular hypertension (OHT) has been increasingly substantiated lately. Repeated SLT is usually needed to control intraocular pressure (IOP), be it as primary or adjunctive therapy. We review the studies available, in terms of SLT repeatability; and conclude comparable efficacy, with success rate, duration and complications similar to those in initial SLT.

Abstract: The efficacy of selective laser trabeculoplasty (SLT) to treat open-angle glaucoma (OAG) and ocular hypertension (OHT) has been increasingly substantiated lately. Repeated SLT is usually needed to control intraocular pressure (IOP), be it as primary or adjunctive therapy. We review the studies available, in terms of SLT repeatability; and conclude comparable efficacy, with success rate, duration and complications similar to those in initial SLT.

Abstract: To present spectral domain optical coherence tomography (OCT) findings during treatment in a case of acute isolated cilioretinal artery occlusion (CLRAO) reversed with intravenous systemic administration of mannitol and carbogen inhalation. Close monitoring with OCT thickness topographic map and cross section scans, every 12 hours, during treatment and till complete reversal of retinal nerve fiber layer edema. Fundus photography and fluorescein angiography (FFA) were used to illustrate occlusion and recanalization. After 72 hours of therapy, visual acuity improved from counting fingers (CF) to 7/10, Snellen’s chart. Consecutively OCT scans showed that the initial macular edema was gradually restored to typical 72 hours of treatment initiation. FFA performed after treatment confirmed recanalization of the cilioretinal artery. Early intervention with the combined intravenous administration of mannitol and carbogen inhalation can reverse acute onset loss of vision due to CLRAO. The reflectivity of retinal layers differs significantly regarding stages of acute CLRAO. In our case report increased reflectivity of the innermost layers of the retina was illustrated and a corresponding reduction in the outer retina and the retinal pigment epithelium and choriocapillaris layers. Macular thickness follow-up data recorded the course of intracellular edema to normal.

Abstract: To present spectral domain optical coherence tomography (OCT) findings during treatment in a case of acute isolated cilioretinal artery occlusion (CLRAO) reversed with intravenous systemic administration of mannitol and carbogen inhalation. Close monitoring with OCT thickness topographic map and cross section scans, every 12 hours, during treatment and till complete reversal of retinal nerve fiber layer edema. Fundus photography and fluorescein angiography (FFA) were used to illustrate occlusion and recanalization. After 72 hours of therapy, visual acuity improved from counting fingers (CF) to 7/10, Snellen’s chart. Consecutively OCT scans showed that the initial macular edema was gradually restored to typical 72 hours of treatment initiation. FFA performed after treatment confirmed recanalization of the cilioretinal artery. Early intervention with the combined intravenous administration of mannitol and carbogen inhalation can reverse acute onset loss of vision due to CLRAO. The reflectivity of retinal layers differs significantly regarding stages of acute CLRAO. In our case report increased reflectivity of the innermost layers of the retina was illustrated and a corresponding reduction in the outer retina and the retinal pigment epithelium and choriocapillaris layers. Macular thickness follow-up data recorded the course of intracellular edema to normal.