Severe ocular trauma is one of the important causes of uniocular sight loss[14] worldwide. Globally, there are 180,000 patients, with approximately 33,000–50,000 of them children[15]. In the management of ocular trauma, one of the fundamental issues facing ophthalmologists worldwide is to restore structural integrity in time to salvage the damaged globe.
This study explored the application of foldable capsular vitreous bodies in the management of severe ocular trauma. We found no evident changes in the 61 patients reviewed after the FCVB implantation, which suggested, even though FCVB could provide continued support to the retina and hold it to its normal anatomical position, they could not revert the damage to the ocular tissues, especially damage to the optic nerve and retinal posterior poles, and thus could not restore the visual functions of the eyes involved. This further demonstrated FCVB serves only to restore the normal shape of the globe without restoring or improving the visual acuity, which was consistent with previous findings[16]. In addition, some patients may experience aggravated corneal opacities after implantation or develop hyperplastic membranes around the capsule, both of which may compromise their vision.
Intraocular pressure is one of the important factors to maintain the homeostasis of the eye. Severe ocular trauma may result in damage to the iris and the ciliary body or loss of ocular contents due to a ruptured globe, affecting intraocular pressure [17]. In our research, we found the intraocular pressure of 91.8% of patients remained in the normal range after the operation. Their UBM images showed the FCVB did not compress the ciliary body and the function of the ciliary body remained unaffected. This illustrated that FCVB can maintain the shape of the posterior chamber to allow the aqueous humor circulation to be slowly recovered until the ciliary body function recovered by itself. However, further investigations are called for on whether the supporting function of FCVB would be sufficient to maintain the intraocular pressure of patients with severe ciliary body defects and avoid low intraocular pressure caused by decreased aqueous humor secretion.
Trauma to the eye may lead to injuries to various ocular structures, including the cornea, one of the most frequently damaged sites. Repeated operations after trauma are also accountable for the loss of corneal endothelial cells [14, 18]. We found the patients’ corneal endothelial cell count had decreased after the operation, but no patients reported corneal endothelial decompensation by their last follow-up clinical visit. During the follow-up window, 52.5% of patients experienced aggravated corneal opacity, with 4 of them reaching the state of corneal leukoma and losing light perception. The cause of corneal opacity may be severe damage to the corneal endothelium caused by large corneal and/or corneal limbal wounds. Localized corneal opacity or severe corneal edema occurred after the first-stage suturing. It was speculated that the implantation of FCVB may have caused detrimental effects on the metabolism of nutrients in aqueous humor, leading to insufficient corneal nutrient supply and consequentially postoperative corneal opacity and even corneal leukoma. Due to the short follow-up window, it requires further exploration to see if FCVB may lead to bullous keratopathy.
Severely ruptured globes are often accompanied by grave damage to the ciliary body, retina, and choroid. During the procedures to manage ruptured globes, it is often observed that the affected eyes have giant retinal tears or proliferative contractile cellular membranes that are difficult to flatten, or detached choroids that cannot be reset, or have persistent low intraocular pressure after the operation. All these made it difficult to remove the silicone oil in the eye after the operation, which led to the development of silicone oil-dependent eyes[19]. Long-term exposure to silicone oil may lead to complications including intraocular toxicity and silicone oil emulsification. Regular replacement of silicone oil is required, which in turn eventually inflicts band keratopathy and/or global atrophy, resulting in the inevitable enucleation[20]. FCVBs have excellent mechanical and optical properties and biocompatibility with human eyes. They are designed to mimic the vitreous cavity. During the implantation procedure, the capsule is injected into the vitreous cavity and inflated by the injection of silicone oil. Afterward, the inflated capsule can effectively support maintain the morphology of the globe and the intraocular pressure. No special postoperative position is required. Since the silicone oil in the capsule will not be in direct contact with the aqueous humor, the silicone oil is not likely emulsified[6, 21]. Among the patients reviewed in this study, the retinal reattachment rate after FCVB implantation was 100%, which was higher than the reattachment rate of posttraumatic retinal detachment treated with vitrectomy combined with inert gas or silicone oil filling, which was 73–89.6% as found in previous studies[22–24].
It has been known that ruptured globes are threatening conditions that in the worst cases may lead to the structural disorder of ocular tissues, leading to the massive leak of eye contents and eventually globe atrophy and even enucleation[25]. In our research, we identified 11 patients who had severely ruptured globes with giant tears and massive loss of eye contents. Their eyes showed obvious dents before the operation. The B-scan showed clear patterns of globe atrophy. After the FCVB implantation, their intraocular pressure returned to the normal range, the axial length of their eyes extended, the eye globe returned to a full shape, and the atrophy was controlled, which negated the need for eye removal. The control rate of globe atrophy in this study was 100%, and none of the 61 patients had eyeball enucleation, which was significantly below the posttrauma enucleation rate of 11.8%-41.8% in studies outside of China[26]. Although there had been 4 patients who underwent conjunctival patching due to corneal leukoma, their eyeballs remained in good shape and they had undergone the procedure for cosmetic reasons.
When a rupture is not managed with care in time, it can easily cause endophthalmitis in the affected eye and even lead to sympathetic ophthalmia in the healthy eye[25]. In our research, there was no report of rupture of the FCVB allergies to silicone, intraocular infection, intraocular hemorrhage, silicone oil emulsification, or sympathetic ophthalmia. This could fully demonstrate the safety of this technique and its contribution to alleviating the patient’s suffering and improving their postoperative quality of life.
In summary, by reviewing cases of application of FVCB in complex, refractory vitreoretinal diseases such as retinal detachment caused by trauma, we have found evidence to support its safety and efficacy in maintaining the morphology and intraocular pressure of posttraumatic eyeballs while eliminating the need for special postoperative positions and avoiding complications such as secondary glaucoma, band keratopathy, or the displacement of the silicone oil filler to other tissues. This procedure can effectively salvage the damaged eyes and negate the need for enucleation, which could inflict inevitable psychological and physical damage to the patient. But we have yet to verify the longest duration that FVCBs can safely stay in the eyes, which will be subject to further investigation.