Corneal endothelial changes induced by pars plana vitrectomy with silicone oil tamponade for retinal detachment

Retrolaminar migration as a complication of intraocular silicone oil injection detected on unenhanced CT

AIM

To describe the clinical and radiologic features of retrolaminar migration silicone oil (SiO) and observe the dynamic position of ventricular oil accumulation in supine and prone.

METHODS

For this retrospective study, 29 patients who had a history of SiO injection treatment and underwent unenhanced head computed tomography (CT) were included from January 2019 to October 2022. The patients were divided into migration-positive and negative groups. Clinical history and CT features were compared using Whitney U and Fisher's exact tests. The dynamic position of SiO was observed within the ventricular system in supine and prone. CT images were visually assessed for SiO migration along the retrolaminar involving pathways for vision (optic nerve, chiasm, and tract) and ventricular system.

RESULTS

Intraocular SiO migration was found in 5 of the 29 patients (17.24%), with SiO at the optic nerve head (n=1), optic nerve (n=4), optic chiasm (n=1), optic tract (n=1), and within lateral ventricles (n=1). The time interval between SiO injection and CT examination of migration-positive cases was significantly higher than that of migration-negative patients (22.8±16.5mo vs 13.1±2.6mo, P<0.001). The hyperdense lesion located in the frontal horns of the right lateral ventricle migrated to the fourth ventricle when changing the position from supine to prone.

CONCLUSION

Although SiO retrolaminar migration is unusual, the clinician and radiologist should be aware of migration routes. The supine combined with prone examination is the first-choice method to confirm the presence of SiO in the ventricular system.

Subepithelial white deposition in the cornea associated with silicone oil and surgical management: a case report

A 36-year-old patient presented with a complaint of an extensive "white scar" in his right eye without pain after silicone oil presence in the vitreous cavity for 12 years. Slit-lamp microscopy revealed extensive corneal leukoplakia and mild limbus neovascularization. Anterior segment optical coherence tomography revealed marked eccentric thickening of the subepithelium and normal thickness of the stroma. We proceeded with silicone oil removal and intraocular and anterior chamber lavage at first, followed by epithelial lesion excision combined with amniotic membrane transplantation 3 months later. The patient was satisfied with the clear cornea appearance.

Macular vascularisation changes analysed using OCT angiography after successful rhegmatogenous retinal detachment repair

AIM

To analyse the macular vascularisation changes analysed using optical coherence tomography angiography (OCTA) after successful rhegmatogenous retinal detachment (RRD) repair by comparing gas vs silicone oil and macula-on vs macula-off.

METHODS

This retrospective data collection included 77 eyes with RRD that underwent pars plana vitrectomy (PPV) and gas or silicone oil tamponade. We performed an OCTA during the postoperative control between 6 and 24mo after the last surgery and evaluated the main parameters measured by OCTA: foveal avascular zone (FAZ) and parafoveolar vascular density (PVD) in the superficial capillary plexus. The patients were divided into four groups: RRD with macular involvement treated with gas tamponade, RRD without macular involvement treated with gas tamponade, RRD with macular involvement treated with silicone oil tamponade and RRD without macular involvement treated with silicone oil tamponade. A one-way ANOVA test combined with post hoc Bonferroni corrections compared FAZ sizes and PVD in all four groups.

RESULTS

The FAZ size was statistically significantly larger in eyes with RRD involving the macula than in those not involving it (P=0.005). There was no statistically significant difference in the FAZ sizes of the eyes treated with silicone oil tamponade compared to those treated with gas tamponade (P=0.54). There was no statistically significant difference in the PVD comparing all four groups.

CONCLUSION

Despite the known risks associated with silicone oil, our findings suggest that the type of tamponade used during PPV to treat an RRD has no significant effect on the future integrity of the PVD or the size of the FAZ in the superficial capillary plexus as measured by OCTA.

Corneal shape changes after vitreoretinal surgery with fluid-gas exchange

To investigate changes in the corneal shape caused by fluid-gas exchange after vitrectomy.This retrospective case-control study included 43 eyes that underwent a combination of cataract surgery and vitrectomy. The corneal shape was measured using anterior segment optical coherence tomography CASIA2. The corneal shape measurements were performed preoperatively, 1 day, 1 week, 1 month, and 3 months after surgery. After calculating the real K value from the actual measured values of the posterior shape of the corneal refracting power and the single posterior corneal refracting power value, Fourier analysis values were examined. Fluid-gas exchange was performed in 23 eyes (gas group), while it was not performed in 20 eyes (nongas group).There was a significant increase in the real K value in the regular and asymmetry components (0.61 ± 0.36, 0.82 ± 0.64) in the gas group only on the first day after surgery (Steel-Dwass test; P < .05). There was also a significant increase in the real K value in the higher-order irregular astigmatism components (Steel-Dwass test; P < .05) for longer periods in the gas versus the nongas group. The shape of the posterior cornea increased in all components in the gas group on the first day after surgery (spherical power -6.35 ± 0.20, regular astigmatism 0.32 ± 0.12, asymmetry 0.22 ± 0.13, and higher-order irregular astigmatism 0.12 ± 0.05, Steel-Dwass test; P < .05).Postoperative changes caused by surgical invasion in the corneal shape appeared to be greater in the gas versus the nongas group, in addition to affecting the time periods of the postoperative corneal shape changes.