Precise prediction of size of a foldable capsular vitreous body via computerized three-dimensional ocular reconstruction in severe retinal detachment

Abstract

Background: This study aimed to precisely predict the size and silicone oil injection of a foldable capsular vitreous body (FCVB) via computerized three-dimensional (3D) ocular reconstruction in the treatment of severe retinal detachment in China.

Methods: The 3D software Unigraphics NX was applied to determine the volume of the inner cavity with 16-30 mm axial length, assigning the anterior and posterior chambers, the FCVB sizes, and the silicone oil injection volume, and modeling the data between the axial length and the FCVB size. In clinical practice, IOL Master was applied to accurately measure the axial length of the contralateral healthy eye to anchor the anterior-posterior and horizontal diameters of the operated eye in horizontal position CT, and compared with the model to recommend the FCVB size and silicone oil amount, and the clinical effect was validated in cases across five hospitals in China.

Results: For the axial length of 16-30 mm, the volume of the inner cavity is 1.2 ml-8.4 ml. FCVB size and silicone oil volume were recommended based on this volume of the inner cavity. Of 253 cases, we noted 11 cases implanted with AV-10P and 1.05 ± 0.21 ml of silicone oil, 41 with AV-12P and 1.58 ± 0.18 ml of silicone oil, 163 with AV-13.5P and 2.48 ± 0.29 ml of silicone oil, 31 with AV-15P and 3.57 ± 0.39 ml of silicone oil, and 7 with AV-17P and 5.71 ± 0.81 ml of silicone oil. There was no significant difference in postoperative visual acuity scores compared with preoperative (P = 0.097), postoperative IOP(10.29 ± 0.57mmHg)was slightly higher than preoperative IOP (9.76 ± 0.48 mmHg), but there was still no statistically significant difference between the two comparisons (P = 0.405).

Conclusion: Three-dimensional reconstruction prediction is a good solution for eyeballs with obvious individualized changes in severe retinal detachment, and this method helps doctors standardize FCVB size selection and the silicone oil amount for patients.

Keywords: 3D reconstruction; FCVB; Retinal detachment; Silicone oil.

Fig. 1

Computerized 3D reconstruction of the stereoscopic view. A Drawing of a simulated eye with an anterior-posterior, horizontal, and vertical diameter of 23.5 mm. B Removing 3 mm of tissue thickness from the eye’s outer shell to obtain an inner ocular cavity diameter of 20.5 mm. C Deriving an inner ocular cavity capacity of 4.5 mm³

Fig. 2

Schematic diagram of the CT inspection

Fig. 3

Straightedge measurement of the ocular axis of the treated eye (from the anterior vertex of the cornea to the posterior vertex of the sclera). A The largest cross-sectional area (largest lens area, with optic nerve) selected from the CT examination image. B Contralateral axis length by IOL Master. C Straightedge measurement of the ocular axis of the contralateral eye. D Straightedge measurement of the ocular axis of the surgical eye

Fig. 4

The procedure of FCVB implantation. A Inject sterile air into the balloon; B Vacuum the balloon; C Fold the balloon into three layers; D Fit into the implant; E Make a scleral incision; F Implant the product; G Close a suture on each side of the drain; H Inject silicone oil; I Inject viscoelastic; J Close the scleral incision; K Ligate the drain; L Close the conjunctival incision

Fig. 5

Efficacy of FCVB implantation in three cases. A In the 10-month follow-up case of severe retinal detachment, anterior segment examination showed that there was good anterior chamber depth and posterior chamber space, and there was a certain distance between the FCVB lens surfaces and the iris; The color-fundus photographic examination showed retinal reattachment. B The patients with silicone oil eyes and corneal opacity were followed up for one and a half years. Silicone oil was in the anterior chamber before operation, and there was corneal pathological edema and opacity; After treatment, anterior segment OCT showed corneal flattening. After wearing overhead artificial eyepiece, the eye appearance was good. C In patients with bullous keratopathy, it was found that the bullae disappeared, the cornea became transparent, OCT showed that there was a FCVB capsule about 200 μm thick in front of the scarred retina