Efficacy of Foldable Capsular Vitreous Body Implants Filled With Light or Heavy Silicone Oil in the Treatment of Silicone Oil-dependent Eyes

Abstract

Purpose: The purpose of this study was to compare the clinical efficacy of foldable capsular vitreous body (FCVB) filled with either light or heavy silicone oil and the incidence of complications after their implantation for the treatment of severe ocular trauma and silicone oil-dependent eyes.

Methods: FCVB filled with either light (n = 16) or heavy (n = 8) silicone oil was implanted in 24 patients. During the 12-month follow-up period, the intraocular pressure, final best-corrected visual acuity, retinal reattachment condition, position of the FCVB, and complications were assessed.

Results: All surgeries were performed without issue. There was no significant difference in preoperative and postoperative best-corrected visual acuity between the two groups. A significant improvement in the intraocular pressure was observed after surgery in both the light silicone oil (P = 0.029) and heavy silicone oil (P = 0.035) groups. None of the patients developed displacement or prolapse of the FCVB. The most common early and late postoperative complications were postoperative hemorrhage (33.3%) and corneal opacification (50%), respectively.

Conclusions: FCVB filled with heavy silicone oil can be used as a supplemental therapy for patients who have lost the anterior segment of their eye, have lesions of the inferior retina, or cannot maintain the prone position for various reasons.

Translational Relevance: Implantation of FCVB combined with heavy silicone oil compensates for the shortcomings of this with light silicone oil, providing patients with more personalized treatment.

Introduction

The vitreous body is a gel-like substance that acts as a refractory medium and focuses light on the retina. However, the vitreous body lacks the capacity for self-regeneration, and any damage that occurs is often permanent.¹ Surgical repair of the vitreous body generally involves the temporary insertion of vitreous substitutes such as sterile gas, inert gas, or silicone oil to stabilize the retina. Silicone oil is widely used in complex vitreoretinopathy owing to its positive properties, such as transparency, safety, and chemical inertness. However, in some cases, vitreous substitutes must remain in place for an extended period or permanently to maintain the structural integrity of the retina; these cases are referred to as silicone oil-dependent eyes. However, the continued use of silicone oil increases the risk of developing glaucoma, keratopathy, optic nerve damage, eyeball atrophy, and proliferative vitreoretinopathy.^2,3 Therefore, for patients with severe ocular trauma and silicone oil-dependent eyes, there is a need to identify long-term vitreous substitutes that can support the eyeball. 

The foldable capsular vitreous body (FCVB) is an emerging vitreous substitute that has been applied recently in clinical practice. The FCVB comprises a 30-µm vitreous-like capsule, a drainage tube, and a drainage valve. It is made of a stable, nontoxic medical-grade liquid silicone rubber. The mechanical properties of liquid silicone rubber include hardness and high strain capability, allowing for a perfect fit of the silicone oil with both the capsule and the eye wall.⁴ Lin et al.⁵ followed patients who underwent FCVB implantation for 3 years and reported that FCVB is effective and safe as a tamponade for long-term vitreous replacement. FCVB is designed to eliminate direct contact between silicone oil and the intraocular tissue structure, thereby greatly decreasing complications caused by emulsification and migration of the silicone oil. In addition, FCVB implantation decreases the psychological trauma and costs associated with the removal of silicone oil. However, to maximize the reattachment of the retina after the insertion of the FCVB, the patient is required to lie prone for 1 week after surgery. Our previous study showed that injection of a viscoelastic substance into the anterior chamber could improve the stability of the intraocular pressure (IOP) and decrease postoperative complications such as hyphema.⁶ To our knowledge, this study is the first to evaluate the outcomes of using FCVB implants filled with heavy silicone oil (Densiron 68) as a tamponade. Heavy silicone oil can facilitate the placement of the FCVB, provide sufficient support to the posterior pole and inferior part of the retina, and prevent underlying proliferative vitreoretinopathy. The use of heavy silicone oil can be particularly beneficial for patients with ocular trauma involving loss of the anterior segment, because it can decrease postoperative capsule displacement and hyphema caused by the prone position required after surgery. As a result, this technique is recommended for patients who cannot maintain a prone position after surgery. 

In this study, we aimed to compare retrospectively the clinical efficacy and incidence of postoperative complications in patients treated with either light or heavy silicone oil-filled FCVB for severe ocular trauma or silicone oil-dependent eyes. 

Methods

Patients were eligible for this study if they were aged ≥18 years and underwent FCVB implantation at the Department of Ophthalmology of the Second Affiliated Hospital of Harbin Medical University from October 2018 to November 2023 to treat the following conditions: (1) a primary disease of severe unilateral eye rupture injury, retinal and/or choroidal detachment owing to retinal choroidal hemorrhage, or retinal rupture; (2) a silicone oil-dependent eye after vitrectomy with secondary complications of glaucoma, corneal degeneration, or silicone oil emulsification; and (3) severe retinal redetachment that developed after silicone oil removal or required >3 months of silicone oil tamponade. All included patients had a visual acuity of <0.05 and an ocular axis ranging from 16.00 mm to 28.00 mm. Pregnant or breastfeeding women and patients who had allergies to silicone materials, scars or FCVB implants, endophthalmitis, uveitis, a single eye, severe impairment of the liver or kidneys, heart disease, disorders of the nervous system, or other systemic illnesses were excluded. Patients who had poor adherence to follow-up or incomplete clinical data were also excluded. The patients were divided into two groups and treated with FCVB filled with either light or heavy silicone oil. In this study, we assigned the patients to the most appropriate treatment group according to their intraoperative eye condition and physical condition. The intraoperative conditions of patients with FCVB with heavy silicone oil are shown in Table 1. 

Table 1.

 

Intraoperative Conditions of Patients With FCVB With Heavy Silicone Oil

 

All surgeries were performed by an experienced senior ophthalmologist who performs thousands of pars plana vitrectomy surgeries per year. Silicone oil was classified into light silicone oil and heavy silicone oil based on density. The light silicone oil used was FCI.S5.7570, which has a dynamic viscosity of 5000 mPa·s and a density of 0.97 g/cm³. For the heavy silicone oil, we used Densiron 68, comprising 30.5% F₆H₈ and 69.5% 5000 mPa·s silicone oil. Densiron 68 has a dynamic viscosity of 1400 mPa·s and a density of 1.06 g/cm³.⁸ 

A standard 23G three-port pars plana vitrectomy was performed to remove the vitreous hemorrhage. If the vitreous cavity was filled with silicone oil, the silicone oil was removed first. The proliferative retinopathy membrane was peeled to relieve retinal traction. In some cases, perfluorodecalin was injected, or an incision was made in the peripheral retina to reveal the subretinal membrane. The subretinal fluid was drained through the retinal tear, and endolaser photocoagulation was performed to treat the incision and other lesions. After air–fluid exchange, the original superior temporal puncture, which was located 3.5 mm away from the corneal limbus, was enlarged to 4 mm parallel to the limbus. Subsequently, the FCVB was folded and implanted into the vitreous cavity using a push injector. FCVBs are available in various sizes, including AV-10P, AV-12P, AV-13.5P, AV-15P, and AV-17P. The quantity of silicone oil injected into capsules of different sizes ranged from 0.7 mL to 5 mL. Typically, we used IOLmaster or A-ultrasound to measure the axial length of both eyes, followed by head and orbital computed tomography scans to determine the horizontal position of the eyeball. Finally, we precisely calculated eyeball size using three-dimensional reconstruction via enhanced magnetic resonance imaging and selected the appropriate capsule size based on FCVB guidelines. The FCVB was then slowly filled with light or heavy silicone oil through a drainage tube. With the assistance of optical fibers, the filling degree of the capsule and the reattachment of the retina were observed under a microscope. The IOP was measured manually to assess its adequacy. Approximately 0.15 to 0.2 mL of sodium hyaluronate was injected to restore the depth of the anterior chamber. Upon completion of the procedure, the drainage tube was ligated and affixed securely to the scleral surface using nonabsorbable sutures. Subsequently, the conjunctiva was sutured with absorbable sutures. Antibiotics and glucocorticoids were administered intravenously to prevent infection and sympathetic ophthalmia. Patients implanted with light silicone oil were asked to lie in the prone position for 1 week, whereas those implanted with heavy silicone oil were asked to lie in the supine position for 1 week. Figure 1 shows a schematic diagram of the FCVB. 

Figure 1.

 

(A) FCVB with light silicone oil. (B) FCVB with heavy silicone oil.

All patients were reviewed by a senior doctor. The IOP and best-corrected visual acuity (BCVA) were recorded before the operation. A slit lamp was used to evaluate eye conditions. All patients underwent eye examination at 1 day, 1 week, 1 month, 3 months, 6 months, and 1 year after surgery. During each visit, the IOP and BCVA were measured. The condition of the eye was assessed using a slit lamp, and any complications were recorded. The retinal reattachment and clarity of the diopter medium were assessed using optical coherence tomography, scanning laser ophthalmoscopy images and a slit lamp. The position of the FCVB was assessed using computed tomography or magnetic resonance imaging if necessary. 

The continuous outcome measures are summarized as the mean ± standard deviation or median (25th percentile–75th percentile [P25–P75]). A t-test was used for statistical analysis if the data were normally distributed. The Wilcoxon rank-sum test was used for statistical analysis if the data were not normally distributed. Statistical Package for Social Sciences (SPSS) version 27.0 software was used to analyze the data. For all the statistical tests, a P value of < 0.05 was considered to indicate statistical significance. 

This study was approved by the institutional review board (IRB) of the Human Research Ethics Committee of the Second Affiliated Hospital of Harbin Medical University (Registration number KY2023-126). The study was performed in accordance with the ethical standards of the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. Informed consent was obtained from all patients included in the study. 

Results

Patient Characteristics

A total of 24 patients with FCVB implants were evaluated; 16 patients were treated with light silicone oil, and 8 patients were treated with heavy silicone oil. The majority of the patients were male (n = 16), and the average age was 41.88 ± 17.12 years (range, 16–68 years). All patients had severe ocular trauma or silicone oil-dependent eyes with various causes. Most patients (n = 16 [66.7%]) had silicone oil-dependent eyes with a silicone oil filling time ranging from 6 months to 10 years. The remaining patients underwent first-stage eyeball rupture suture surgery and second-stage vitrectomy combined with FCVB silicone oil implantation (n = 7 [29.1%]) or severe retinal and choroidal detachment (n = 1 [4.2%]). The clinical data and characteristics of the patients are listed in Table 2. The preoperative and postoperative IOP and BCVA are summarized in Tables 3, 4, and 5. The median preoperative IOP was 7.85 mm Hg (P25–P75, 6.20–13.75 mm Hg) in the light silicone oil group and 10.50 mm Hg (P25–P75, 6.25–12.00 mm Hg) in the heavy silicone oil group. The median preoperative BCVA was light perception in the light silicone oil group and hand motion in the heavy silicone oil group. There were no significant differences in sex, preoperative BCVA, and IOP between the two groups. However, patients in the heavy silicone oil group were significantly older than those in the light silicone oil group (53 ± 17.2 vs. 36.13 ± 14.8 years; P = 0.021). 

Table 2.

 

Clinical Data and Patient Characteristics

 

Table 3.

 

Comparison of Preoperative and Postoperative Values Between the Two Groups

 

Table 4.

 

Comparison of Preoperative and Postoperative IOP in the Two Groups

 

Table 5.

 

Comparison of Preoperative and Postoperative BCVA Between the Two Groups

 

Postoperative Assessment

Postoperative IOP and BCVA

One month after surgery, the median IOP was 14.90 mm Hg (P25–P75, 11.25–25.75 mm Hg) in the light silicone oil group and 16.50 mm Hg (P25–P75, 8.00–20.50 mm Hg) in the heavy silicone oil group. The median postoperative IOP was significantly greater than the preoperative IOP in both the light silicone oil group (14.90 mm Hg [P25–P75, 11.25–25.75 mm Hg] vs. 7.85 mm Hg [P25–P75, 6.20–13.75 mm Hg]; P = 0.029) and the heavy silicone oil group (16.50 mm Hg [P25–P75, 8.00–20.50 mm Hg] vs. 10.50 mm Hg [P25–P75, 6.25–12.00 mm Hg]; P = 0.035). 

One year after surgery, of the sixteen patients in the light silicone oil group, six (37.5%) had no light perception, six (37.5%) had preserved light perception, three (18.8%) had hand motion, and one (6.3%) had a finger count. In contrast, of the eight patients in the heavy silicone group, two (25.0%) patients had no light perception, one (12.5%) had light perception, and five (62.5%) had hand motion. In the light silicone oil group, one patient (6.3%) had improved vision, thirteen patients (81.3%) had no obvious visual improvement, and two patients (12.5%) had decreased vision. In the heavy silicone oil group, one patient (12.5%) had improved vision, six patients (75%) had no obvious improvement, and one patient (12.5%) had decreased vision. However, the changes in the BCVA after the operation in both the light silicone oil (P = 0.564) and heavy silicone oil (P = 0.655) groups were not significant. 

Position of the FCVB and Retinal Attachment

After surgery, the FCVB remained properly positioned and provided sufficient support to the eyeball in all patients. In all patients except one, the drainage valve under the conjunctiva remained completely wrapped. 

The refracting media remained transparent in nine patients (56.3%) in the silicone oil group. Retinal reattachment was observed in eight patients (88.9%). In these patients, the capsule was positioned very close to the retina, which improved the support provided to the retina. For all seven patients (43.7%) in the light silicone oil group who presented with opacity within the refractive media, the FCVB provided adequate support to the eyeball. Of the eight patients in the heavy silicone oil group, three (37.5%) had transparent refractive media, and two (66.7%) had retinal reattachment. 

Postoperative Complications

None of the patients developed silicone oil leakage or capsular rupture. Although seven patients presented with mild eyeball atrophy before the operation, no further atrophy progression was observed after the surgery. Table 6 provides a summary of the early postoperative complications in patients treated with light silicone oil and heavy silicone oil. The most common early postoperative (within 1 month) complication was postoperative hemorrhage, including hyphema, retinal hemorrhage, and corneal blood staining. In the light silicone oil group, postoperative hyphema occurred in four patients (25%), whereas retinal hemorrhage occurred in two patients (12.5%). In the heavy silicone oil group, one patient (12.5%) developed retinal hemorrhage, and another patient developed corneal blood staining; this patient exhibited corneal blood contamination before surgery owing to severe ocular trauma. The second most common complication was increased IOP. This complication was observed in four patients (25%) treated with light silicone oil and one patient (12.5%) treated with heavy silicone oil. In three of these patients, IOP was controlled with IOP-lowering eyedrops; in the other two patients, the IOP could not be reduced. Other early complications included anterior chamber fibrin (12.5%) and a shallow anterior chamber (12.5%). Patients with postoperative inflammatory reactions were treated with gentamicin dexamethasone via subconjunctival injection. The inflammatory response subsided within 1 week after surgery. 

Table 6.

 

Early Postoperative Complications

 

Late postoperative complications (1 month to the end of the last follow-up) are summarized in Table 7. In the light silicone oil group, nine patients (56.25%) developed corneal opacification owing to preoperative conditions, which included corneal blood staining (n = 1 [11.1%]), corneal leucoma (n = 1 [11.1%]) and corneal degeneration (n = 2 [22.2%]). Other late complications included exposure of the drainage tube (n = 1 [6.25%]) and sympathetic ophthalmitis (n = 1 [6.25%]). The exposed drainage valve was successfully reattached to the sclera with a conjunctival flap cover. The patient with sympathetic ophthalmitis was successfully treated with hormone therapy. 

Table 7.

 

Late Postoperative Complications

 

There were no statistically significant differences in the incidence of early or late postoperative complications between the two groups. Two representative cases with different FCVB locations are presented in Figures 2 and 3. 

Figure 2.

 

Patient 14 (28 years old, female) presented with right eyeball rupture. She underwent removal of the intraocular foreign body, pars plana vitrectomy, and silicone oil tamponade. Owing to retinal detachment and atrophy of the eyeball after one year, implantation of an FCVB filled with light silicone oil was performed at our hospital. Her oculus dexter vision (VOD) was hand motion (HM), and her IOP was 12.1 mm Hg. (A1) Preoperative optical coherence tomography image showing stiffness and detachment of the posterior polar retina. (B1) Orbital computed tomography image before surgery. (C1) Preoperative B-scan ultrasound image. During the operation, the subretinal membrane, the anterior proliferative membrane was excised, retinal repositioning was performed after gas‒liquid exchange, and the FCVB was implanted and filled with light silicone oil. The postoperative IOP was 11 mm Hg. Early postoperative visual acuity was maintained at HM, and exudation of the fibrous proliferative membrane in the pupil area was observed. Until the end of the last follow-up, visual acuity remained at light perception. (D1) Postoperative scanning laser ophthalmoscopy image showing the inferotemporal aspect of the retinal proliferative membranes and scars. (E1) Postoperative optical coherence tomography image showing a flat retina with the capsular wall fitting closely to the retina. F1 Orbital computed tomography image after surgery. (G1–H1) Anterior segment photographs revealing corneal opacification, a fibrous proliferative membrane in the pupil area, a drainage tube under the conjunctiva, and a well-positioned FCVB.

Figure 3.

 

Patient 22 (57 years old, male) accidentally injured his left eye. At the local hospital, the diagnosis was “left eyeball rupture, traumatic lens dislocation, traumatic hyphema, traumatic iris defect, traumatic retinal detachment” with a sutured scleral laceration. Three months later, the oculus sinister vision (VOS) of his left eye was no light perception (NLP), and the IOP was 7 mm Hg. He underwent a second-stage vitrectomy and FCVB implantation filled with heavy silicone oil. (A2) Preoperative magnetic resonance imaging image showing an irregular shape of the left eyeball with uneven enhancement of the inner circumference. (B2) Preoperative B-scan ultrasound image showing that the retina was completely detached. (C2–F2) During the operation, the preretinal hyperplastic membrane was resected carefully, the stiff retina was flattened, the subretinal proliferation membrane was removed, the FCVB was implanted after gas‒liquid exchange, and heavy silicone oil was injected. G2-H2 Twenty days after surgery, scanning laser ophthalmoscopy showed that the wrinkled retina had been flattened, optical coherence tomography showed retinal reattachment, and the retina was well anastomosed with the capsule. (I2) Postoperative anterior segment photograph showing that the cornea was slightly opacified, most of the iris was defective, and the FCVB drainage tube was buried under the conjunctiva without foreign body sensation.

Discussion

Patients who suffer from severe ocular rupture injuries experience psychological trauma in addition to destruction of the eyeball's structure and function. These injuries are followed typically by severe proliferative vitreoretinopathy and loss of eye contents. The restoration of vision and retention of eyeball function remain major challenges for ophthalmologists. FCVB have been used clinically as a permanent replacement successfully in patients with silicone oil-dependent eyes and severe ocular trauma.^9,10 

Current FCVB techniques use light silicone oil as a tamponade. However, this technique requires the injection of a considerable amount of oil to support the retina in all directions. Overfilling of the FCVB could alter its shape, and, thus, the implant will not exert enough pressure to close the retina. This factor eventually leads to ischemia of the anterior segment of the retina. This condition decreases the functioning of the ciliary body, leading to inadequate secretion of aqueous humor. Ultimately, this cascade of events may lead to corneal opacification and eyeball atrophy. Moreover, patients can find it difficult to maintain a prone position for 1 week. An alternative approach is to use heavy silicone oil. However, although heavy silicone oil can provide better support to the posterior pole of the retina, this oil is more likely to emulsify. Moreover, the long-term use of heavy silicone oil can increase the risk of developing inflammatory reactions and an increased IOP. Therefore, heavy silicone oil cannot be used in patients with silicone oil-dependent eyes and severe eye trauma unless it is implanted in an FCVB.^11,12 Therefore, in this study, we aimed to evaluate for the first time the efficacy and clinical outcomes of FCVB filled with heavy silicone oil in relation to FCVB filled with light silicone oil. 

Consistent with the findings of Zhang et al.,^3,13 our study confirmed that, irrespective of the gravity of the silicone oil used, FCVB implantation did not improve BCVA after surgery. However, a significant increase in the IOP after surgery was observed in both treatment arms. In addition, displacement of the FCVB after surgery was not observed in any of the patients, and none of the patients developed further eyeball atrophy. These findings highlight the efficacy and safety of FCVB filled with heavy silicone tamponade. 

In our study, the most common early postoperative complication was hemorrhage. Although the incidence of hemorrhage in the heavy silicone oil group was less than that in the light silicone oil group, the difference was not statistically significant. Various factors can lead to postoperative hemorrhage, including hemorrhage of the iridial, ciliary, or retinal vessels. Hemorrhages are usually small and can be absorbed easily. However, if the blood is not absorbed, timely anterior chamber irrigation is necessary. In patients with light silicone oil, remaining in the prone position can lead to an accumulation of blood in the anterior chamber or behind the cornea. The accumulation of blood can ultimately increase the IOP and increase the risk of fibrous proliferative membrane development. Simultaneously, this accumulation contributes to a decrease in corneal endothelial cells, leading to a progressive loss of corneal transparency. The gradual decompensation of the cornea eventually manifests as corneal leucoma. Postoperative hyphema can also affect early observation of the FCVB position and retinal reattachment.^14,15 Because patients treated with FCVB with heavy silicone oil do not need to stay in the prone position, this technique can decrease the postoperative complications associated with hemorrhage. 

In our study, five patients developed increased IOP after surgery, three of whom were successfully treated with IOP-reducing eyedrops. The factors leading to increased IOP included postoperative hemorrhage (n = 3), blockage of the anterior chamber (n = 1) and blockage of the trabecular meshwork (n = 1). The IOP did not return to normal after treatment in two of the patients. The elevated IOP in patient 4 was attributed to neovascularization of the pupil margin before FCVB implantation. Neovascularization combined with the development of a proliferative membrane eventually blocks the anterior chamber and impedes the efficient drainage of excess aqueous humor. Patient 11 presented with traumatic pupil dilation owing to ocular trauma before surgery, and a silicone oil bubble was visible in the anterior chamber. This patient was treated with intraocular silicone oil for >1 year, which eventually led to the emulsification of the silicone oil. The emulsified silicone oil formed particles that blocked the trabecular meshwork and prevented the aqueous humor from flowing normally, leading to the development of secondary glaucoma.¹⁶ 

The third most prevalent early postoperative complication was the occurrence of a shallow anterior chamber. This condition is particularly common in patients with iris coloboma and loss of the anterior segment. Therefore, patients presenting with these conditions should be administered a viscoelastic agent when treated with an FCVB with light silicone oil to prevent displacement of the capsule. The adoption of the supine position after surgery in the heavy silicone oil group effectively prevented excessive forwards movement of the capsular vitreous body, thereby preventing potential compression of the ciliary body and anterior chamber angle and ensuring the stability of the FCVB position. 

The most common late postoperative complication was corneal opacification. Patients treated with light silicone oil had a greater incidence of corneal opacification (56.25%) than did those treated with heavy silicone oil (37.5%). Various factors can lead to corneal opacification, including large preoperative corneal lacerations, multiple intraocular surgeries owing to severe trauma, hyphema, and long-term filling of the eye with silicone oil. Extensive ocular trauma and multiple surgeries can damage the ciliary body, leading to a decrease in its function. Damage to the ciliary body diminishes aqueous humor secretion, resulting in a gradual decrease in IOP or a shallow anterior chamber after surgery. Over time, these conditions can contribute to corneal dystrophy and the progressive development of corneal opacification. Hyphema can impair the pumping function of endothelial cells, ultimately causing damage to the corneal endothelium. This damage can lead to swelling of the corneal stroma and result in corneal endothelial decompensation.¹⁷ In this study, 16 patients were treated with silicone oil before FCVB implantation. The duration of the treatment ranged from 6 months to 10 years. Studies have shown that prolonged use of ocular silicone oil can increase the risk of corneal endothelial cell loss.¹⁸ Moreover, previous studies have shown that the emulsification rate of silicone oil can reach 100% within 1 year after implantation.^19,20 However, heavy silicone oil emulsifies more rapidly than light silicone oil. The emulsified silicone oil particles can easily penetrate the anterior chamber or attach to the posterior surface of the cornea from the vitreous body cavity, particularly in patients with dysfunctional phakic or suspensory ligaments following eyeball rupture. The silicone oil particles eventually cause corneal lesions that are difficult to remove surgically and may affect visual function following implantation of the FCVB. Another common late postoperative complication observed in patients treated with light silicone oil was the development of a fibrous proliferative membrane within the pupil area. However, because this membrane did not affect vision, it was not treated. 

Our study has some limitations that must be acknowledged. The small sample size in our study may have limited the statistical power of our findings. Moreover, we did not evaluate the long-term impact of this procedure. Therefore, larger longitudinal studies are required to verify the long-term impact of using FCVB filled with heavy silicon oil to treat patients with silicon oil-dependent eyes and severe ocular trauma. 

Conclusions

The implantation of FCVB filled with heavy silicone oil is an effective and safe treatment and has several advantages. First, an FCVB filled with heavy silicone oil eliminates the need for the patient to remain in a prone position after surgery and thus decreases the incidence of complications such as hyphema. The supine position is more comfortable for elderly patients who are on dialysis or have a history of cerebral or myocardial infarction. In addition, heavy silicone oil improves the support of the posterior and inferior parts of the retina and maximizes retinal reattachment while lowering the risk of eyeball atrophy. Finally, in patients who have lost their anterior segment owing to severe ocular trauma, heavy silicone oil decreases the exposure and movement of the valve and minimizes the forward migration of the FCVB. 

Acknowledgments

Supported by the National Natural Science Foundation of China (No. 82171103). The journal's Rapid Service and Open Access fees were funded by the authors. 

Disclosure: H. Lu, None; Y. Shen, None; P. Fan, None; M. Sun, None; Z. Zhang, None; B. Jiang, None; D. Sun, None