Primary posterior capsulotomy in femtosecond laser-assisted cataract surgery: In vivo spectral-domain optical coherence tomography study

Incidence and Risk Factors for Berger's Space Development after Uneventful Cataract Surgery: Evidence from Swept-Source Optical Coherence Tomography

Background: This study investigates the incidence and risk factors for the development of Berger’s space (BS) after uneventful phacoemulsification based on swept-source optical coherence tomography (SS-OCT). Methods: Cataractous eyes captured using qualified SS-OCT images before and after uneventful phacoemulsification cataract surgery were included. Six high-resolution cross-sectional anterior segment SS-OCT images at 30° intervals were used for BS data measurements. BS width was measured at three points on each scanned meridian line: the central point line aligned with the cornea vertex and two point lines at the pupil’s margins. Results: A total of 223 eyes that underwent uneventful cataract surgery were evaluated. Preoperatively, only two eyes (2/223, 0.9%) were observed to have consistent BS in all six scanning directions. BS was observed postoperatively in 44 eyes (44/223, 19.7%). A total of 13 eyes (13/223, 5.8%) with insufficient image quality, pupil dilation, or lack of preoperative image data were excluded from the study. A total of 31 postoperative eyes with BS and 31 matched eyes without BS were included in the final data analysis. The smallest postoperative BS width was in the upper quadrant of the vertical meridian line (90°), with a mean value of 280 μm. The largest BS width was observed in the opposite area of the main clear corneal incision, with a mean value >500 μm. Conclusions: Uneven-width BS is observable after uneventful phacoemulsification. Locations with a much wider BS (indirect manifestation of Wieger zonular detachment) are predominantly located in the opposite direction to the main corneal incisions.

Automatic segmentation of intraocular lens, the retrolental space and Berger's space using deep learning

PURPOSE

To develop and validate a deep learning model to automatically segment three structures using an anterior segment optical coherence tomography (AS-OCT): The intraocular lens (IOL), the retrolental space (IOL to the posterior lens capsule) and Berger's space (BS; posterior capsule to the anterior hyaloid membrane).

METHODS

An artificial intelligence (AI) approach based on a deep learning model to automatically segment the IOL, the retrolental space, and BS in AS-OCT, was trained using annotations from an experienced clinician. The training, validation and test set consisted of 92 cross-sectional OCT slices, acquired in 47 visits from 41 eyes. Annotations from a second experienced clinician in the test set were additionally evaluated to conduct an inter-reader variability analysis.

RESULTS

The AI model achieved a Precision/Recall/Dice score of 0.97/0.90/0.93 for IOL, 0.54/0.65/0.55 for retrolental space, and 0.72/0.58/0.59 for BS. For inter-reader variability, Precision/Recall/Dice values were 0.98/0.98/0.98 for IOL, 0.74/0.59/0.62 for retrolental space, and 0.58/0.57/0.57 for BS. No statistical differences were observed between the automated algorithm and the inter-reader variability for BS segmentation.

CONCLUSION

The deep learning model allows for fully automatic segmentation of all investigated structures, achieving human-level performance in BS segmentation. We, therefore, expect promising applications of the algorithm with particular interest in BS in automated big data analysis and real-time intra-operative support in ophthalmology, particularly in conjunction with primary posterior capsulotomy in femtosecond laser-assisted cataract surgery.

Real-time intraoperative OCT imaging of the vitreolenticular interface during pediatric cataract surgery

PURPOSE

To report on the use of intraoperative optical coherence tomography (OCT) imaging of the vitreolenticular interface (VLI) during pediatric cataract surgery and to determine the incidence of VLI dysgenesis and surgical difficulties.

SETTING

Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium.

DESIGN

Retrospective cohort study.

METHODS

This study included 51 pediatric patients who underwent cataract surgery between April 2016 and December 2018. Video recordings and OCT images of the VLI were analyzed and compared. VLI dysgenesis was considered present when intraoperative OCT images demonstrated partial or total adhesions between the posterior lens capsule and the anterior hyaloid membrane. Video recordings were analyzed to describe surgical difficulties, more specifically: inability to create a calibrated primary posterior continuous curvilinear capsulorhexis (PPCCC), occurrence of vitreous prolapse, need for anterior vitrectomy, and complicated IOL implantation.

RESULTS

Of the 51 patients included, VLI dysgenesis was demonstrated in 27 patients (52.9%). The incidence of VLI dysgenesis was greater in children with unilateral cataract (72.4%), and children with a posterior capsule plaque (90%). PPCCC was challenging in 20 patients. A defect of the anterior hyaloid membrane was found in 16 patients. Anterior vitrectomy or cutting vitreous strands with scissors was necessary in 10 patients.

CONCLUSIONS

Intraoperative OCT images were an excellent tool to evaluate the VLI and to demonstrate the presence of VLI dysgenesis during pediatric cataract surgery. Performing a calibrated PPCCC was more challenging in the presence of VLI dysgenesis. This can subsequently expose a defect in the anterior hyaloid membrane, which may result in vitreous prolapse.

The Emerging Role of Anterior Segment Optical Coherence Tomography in Cataract Surgery: Current Role and Future Perspectives

Modern-day cataract surgery has achieved equivalence with refractive surgery, thus requiring surgeons to perform all possible pre-emptive exercises to mitigate intraoperative complications. In this direction, we possess a tremendous amount of technology to understand the preoperative status of the lens. Anterior segment optical coherence tomography (ASOCT) is one such tool, which has played a distinctive role in imaging various forms of cataracts. In this review, we critically analyse the practical role of ASOCT in the preoperative and intraoperative periods from a cataract surgeon's perspective. After a thorough literature assessment, it was substantiated that the cross-sectional imaging ability of ASOCT can demonstrate delicate anatomical and pathological lenticular changes in a visually and clinically comprehensible way. The objective grading of immature cataracts to intralenticular and posterior capsular details in mature/white, posterior polar, traumatic and other forms of cataracts paves the way for various practical innovations as and when required. Hence, preoperative more than intraoperative ASOCT-derived lenticular knowledge is of immense help in careful surgical planning, with improved complication rates.

[New intraocular lens designs for femtosecond laser-assisted cataract operations : Chances and benefits]

BACKGROUND

The perfection and high reproducibility of capsulotomy in femtosecond laser-assisted cataract surgery (FLACS) lead to the possibility of new intraocular lens (IOL) designs for capsulotomy fixed implantation.

ISSUE

Which different designs have so far been presented for which problems in capsulotomy fixation?

MATERIAL AND METHOD

An evaluation of the literature and conference data was carried out.

RESULTS

Currently four different types of femtolenses for capsulotomy fixation are described in the literature or are commercially available. The first described was the lens in the bag or Tassignon IOL, which was developed for secondary cataract prevention, the second was the Masket IOL for reduction of negative dysphotopsia and third the 90F designed by Dick. All three types are or will be produced by Morcher. The fourth lens is the Femtis from Oculentis. All lenses are characterized by a high level of safety during implantation, The Tassignon lens leads to reduction of secondary cataract, especially in juvenile cataract because of the additional posterior capsulotomy. In studies the Masket IOL could show a decrease of negative dysphotopsia. In comparison to standard lenses, the 90F and Femtis in particular showed better results with respect to tilt, rotation and decentration.

CONCLUSION

The new IOL designs for capsulotomy fixation show a safe implantation procedure and indications for a very stable position in the capsular sac. Further studies must be carried out to confirm the possible advantages in comparison to standard IOL with respect to postoperative results for refraction, tilt, rotation and decentration and possible induction of aberrations.

Posterior capsule rupture with FLACS due to erroneous interpretation of a high OCT intensity area in anterior vitreous

Purpose

We describe a case of posterior capsule rupture during femtosecond laser-assisted cataract surgery (FLACS) due to direct exposure of the posterior capsule to the laser beam.

Observations

A 47-year-old man underwent FLACS for anterior capsule opacity. The CATALYS® system automatically detected the posterior capsule from the optical coherence tomography (OCT) images, after which the operator manually adjusted the line of posterior capsule. Femtosecond laser irradiation was presumed to be completed successfully. However, upon insertion of a phaco-tip, the diced nucleus of the lens dropped into the vitreous chamber. Reviewing intraoperative OCT images of the treatment summary to check the area irradiated by laser, an arc-shaped high-intensity area was observed behind the posterior capsule. This high-intensity was misinterpreted as the posterior capsule, which led to error in application of laser beam during procedure.

Conclusions and importance

Comparison of data acquired using different imaging modalities could enable correct identification of the posterior capsule.

Femtosecond laser-assisted cataract surgery: A review

PURPOSE

Review scientific literature concerning femtosecond laser-assisted cataract surgery.

METHODS

Following databases were searched: CENTRAL (Cochrane Eyes and Vision Trials Register; Cochrane Library: Issue 2 of 12, June 2019), Ovid MEDLINE^® without Revisions (1996 to June 2019), Ovid MEDLINE^® (1946 to June 2019), Ovid MEDLINE^® Daily Update June 2019, MEDLINE and MEDLINE Non-Indexed Items, Embase (1980-2019), Embase (1974 to June 2019), Ovid MEDLINE^® and Epub Ahead of Print, in-Process & Other Non-Indexed Citations and Daily (1946 to June 2019), Web of Science (all years), the metaRegister of Controlled Trials ( www.controlled-trials.com ), ClinicalTrials.gov ( www.clinicaltrial.gov ) and World Health Organization International Clinical Trials Registry Platform ( www.who.int/ictrp/search/en ). Search terms/keywords included 'Femtosecond laser' combined with 'cataract', 'cataract surgery'.

RESULTS

Based on quality of their methodology and their originality, 121 articles were reviewed, including randomised controlled trials, cohort studies, case-controlled studies, case series, case reports and laboratory studies. Each step of the femtosecond laser-assisted cataract surgery procedure (corneal incisions, arcuate keratotomies, capsulotomy and lens fragmentation) has been discussed with relevance to published outcomes, as well as complication rates of femtosecond laser-assisted cataract surgery, and what we can learn from the larger studies/meta-analyses and the economics of femtosecond laser-assisted cataract surgery within different healthcare settings.

CONCLUSION

Studies suggest that the current clinical outcomes of femtosecond laser-assisted cataract surgery are not different to conventional phacoemulsification surgery and it is not cost effective when compared with conventional phacoemulsification surgery. In its current technological form, it is a useful surgical tool in specific complex cataract scenarios, but its usage has not been shown to translate into better clinical outcomes.

Impact of fluidic parameters during phacoemulsification on the anterior vitreous face behavior: Experimental study

Purpose

To evaluate the eff ect of different aspiration flow rates (AFR) and bottle heights (BH) on vitreous face (AVF) during phacoemulsifi cation.

Methods

Experimental study in 20 porcine eyes. Transzonular viscodissection was performed between the posterior capsule(PC) and AVF to dissect out the Berger's space. Triamcinolone acetonide was injected into this space to aid visualization with ultrasound B-Scan(USG). Realtime USG was performed during phacoemulsifi cation. Eyes were divided randomly into-Group I: Low parameters(AFR = 20 cc/min, BH = 90 cm, vacuum = 400 mmHg),and Group II: High parameters (AFR = 40 cc/min, BH = 110 cm, vacuum=650 mm Hg).

Results

15 eyes were analysed (8 in Group I; 7 in Group II). In all eyes, forward and backward movement of the PC was seen when going from foot position 0 to 1, or on occlusion break. Amplitude of these movements was much greater in Group II compared to Group I. There was no PC rupture in either group. In 2 of the 7 eyes in Group II, USG showed a sudden, spontaneous dispersion appearance of sono-opaque echoes in the vitreous cavity alongwith disappearance of the well-defi ned, crescentic stained space despite an intact PC. This suggests rupture of the AVF, leading to dispersion of the triamcinolone into the entire vitreous cavity. No AVF rupture was seen in Group I.

Conclusion

We report a rarely described entity of AVF rupture with intact PC. The use of high AFR and BH may have clinically invisible detrimental consequences to the anterior vitreous face.

Transzonular capsulo-hyaloidal hydroseparation with optional triamcinolone enhancement: A technique to detect or induce anterior hyaloid membrane detachment for primary posterior laser capsulotomy

Primary posterior laser capsulotomy (PPLC) requires adequate visualization and spacing of the posterior lens capsule (PLC) and anterior hyaloid membrane (AHM). After intraocular lens implantation and watertight incision hydration, the laser is redocked for optical coherence tomography reimaging. If the PLC and AHM are not imaged or interspaced adequately, transzonular capsulo-hyaloidal hydroseparation is attempted by rinsing the zonular fibers with fluid. If the PLC or AHM are still not detected or discernable, an attempt follows to mark the Berger space using diluted triamcinolone acetate. Before hydroseparation, the AHM or PLC are often invisible or variably attached. If structures cannot be defined, triamcinolone-added hydroseparation is often effective in defining the AHM and Berger space. Transzonular capsulo-hyaloidal hydroseparation with an optional triamcinolone acetate addition can initiate or complete AHM detachment and improve visibility and patency of Berger space for augmenting control and feasibility of PPLC.