Correlation between intraoperative and postoperative vaulting of the EVO implantable Collamer lens: a retrospective study of real-time observations of vaulting using the RESCAN 700 system

Background Implantable Collamer lens (ICL) vaulting is one of the most important parameters for the safety, aqueous humor circulation, and lens transparency after ICL implantation. This study aimed to investigate the factors associated with the actual vaulting after refractive EVO-ICL surgery. Methods This retrospective study included patients who underwent EVO-ICL surgery at a tertiary eye hospital between October and December 2019. A RESCAN 700 was used for the intraoperative and CIRRUS HD-OCT was used for postoperative observation of vaulting. Subjective and objective refractions, anterior ocular segment, corneal morphology, intraocular pressure (IOP), anterior chamber volume (ACV), crystalline lens rise (CLR), white-to-white distance (WTW), anterior chamber depth (ACD), axial length, corneal endothelial cell density (ECD), and fundoscopy were examined. A multivariable analysis was performed to determine the factors independently associated with 1-month postoperative vaulting. Results Fifty-one patients (102 eyes) were included. Compared with the eyes with normal vaulting, those with high vaulting had higher preoperative diopter values (P = 0.039), lower preoperative corrected visual acuity (P = 0.006), lower preoperative IOP (P = 0.029), higher preoperative ACD (P = 0.004), lower preoperative CLR (P = 0.046), higher ICL spherical equivalent (P = 0.030), higher intraoperative vaulting (P < 0.001), and lower IOP at 1 month (P = 0.045). The multivariable analysis showed that the only factor independently associated with high vaulting at 1 month after surgery was the intraoperative vaulting value (odds ratio = 1.005, 95% confidence interval: 1.002–1.007, P < 0.001). The intraoperative and 1-month postoperative vaulting values were positively correlated (R2 = 0.562). Conclusions The RESCAN700 system can be used to perform intraoperative optical coherence tomography to predict the vaulting value of ICL at 1 month.

Bilateral posterior lamellar corneal transplant surgery in an infant of 17 weeks old: surgical challenges and the added value of intraoperative optical coherence tomography

To describe the surgical challenges, management, and value of intra-operative optical coherence tomography in a case of a bilateral Descemet Stripping Automated Endothelial Keratoplasty corneal transplantation at 17 weeks of age for the treatment of severe posterior polymorphous corneal dystrophy resulting from a de novo mutation of the OVOL2-gene.

Capabilities of intraoperative OCT during femtoassisted phacoemulsification of cataract in congenital lens ectopia

Purpose. To prevent intraoperative complications during fixation of the IOL-intracapsular ring-capsule bag complex during femto-assisted phacoemulsification of cataract complicated by congenital lens ectopia (Marfan syndrome) using intraoperative OCT. Material and methods. 3 men (6 eyes), with a diagnosis of cataract complicated by congenital ectopia of the lens (Marfan syndrome). The age of patients ranged from 19 to 25 years. Cataract phacoemulsification (CFE) with femto support and hydrophobic IOL implantation was performed by all patients. Fixation of complex "IOL-intracapsular ring-capsule bag" in sulcus ciliaris was performed with the control of intraoperative OCT. Results. BCVA was 0.6-0.8 at the first day after the operation. According to ultrasound biomicroscopy (UBM), the IOL was in the capsule bag in a horizontal position in all cases. Any damage of the iris and ciliary body was not found. After 6 months, according to UBM, a stable horizontal position of the IOL and the consistency of suture fixation of the «intracapsular ring-capsule bag-IOL» complex was recorded in all patients. Conclusion. The use of intraoperative OCT allows to accurately determine the individual anatomical location of the sulcus ciliaris and provide visual control of the IOL suturing and the «intracapsular ring-capsule bag» complex in congenital lens tectopia, avoiding excessive trauma of the surrounding eye tissues, and also to ensure a stable horizontal position of the IOL in the postoperative period. Key words: intraoperative optical coherence tomography, femtoassisted cataract phacoemulsification, congenital lens ectopia.

Features of the formation of "Big Bubble" during deep anterior lamellar keratoplasty

Purpose. To determine the optimal channel parameters in the deep layers of the corneal stroma when performing deep anterior lamellar keratoplasty (DALK), providing the maximum frequency of air bubble formation, under the control of intraoperative optical coherence tomography. Material and methods. The study was performed at 30 patients (30 eyes) with a diagnosis of stage III keratoconus. The average age of patients is 31±7 years. All patients were divided into groups consisting of 10 patients, depending on the choice of the topographic orientation of the channel for pneumodissection in the deep layers of the corneal stroma when performing DALK: 1st group – the channel is located towards the center of the cornea; 2nd group – the channel is located paracentral to the temporal side; 3rd group – the channel is located paracentral to the nasal side. In all cases, DALK was performed with a femtosecond laser Femto LDV Z8 (Ziemer, Switzerland). The length of the formed femto channels were variable and amounted to 1.0, 1.5, 2.0, 2.5 and 3.0 mm in each group. Results. The use of intraoperative OCT demonstrated that in all 30 cases the depth of the channel for pneumodissection corresponded to preoperative calculations and amounted to 97±5µm to DM. It was found that the bedding of the channel at a distance of 100µm to the descemet membrane (DM) and its paracentral orientation is characterized by a greater frequency of formation of the «Big Bubble» in comparison with its central orientation: 3rd group – 90% and 2nd group – 80% against 1st group – 60% of cases. The study of the effect of the length of the channel for pneumodissection on the ease of formation of the "Big Bubble" demonstrated that more attempts are required to inject sterile air when channels of 2.0, 2.5, 3.0 mm being used than with short channels of 1.0, and 1, 5 mm (average 3 attempts versus 1.5 attempts, respectively). Conclusion. The paracentral orientation of the location of the channel for pneumodissection is accompanied by a higher percentage of formation of the "Big Bubble" than the central location of the channel. Manual extension of femtochannels having length of 1.0, 1.5 mm, directly with a microsurgical spatula 30G followed by inserting a metal cannula into the channel minimizes the number of attempts to inject sterile air, that facilitates the formation of the "Big Bubble". Performing DALK applying the function of intraoperative OCT allows to control the accuracy of all stages of the operation, including the stage of formation of a large air bubble. Performing DALK with the applying of the function of intraoperative OCT allows to control the accuracy of all stages of the operation, including the stage of formation of a large air bubble. Key words: deep anterior lamellar keratoplasty, Big Bubble, channel for pneumodissection