Combined use of an iris hook and pupil expansion ring for femtosecond laser-assisted cataract surgery in patients with cataracts complicated by insufficient mydriasis and an ectopic pupil

Dilation devices in cataract surgery

PURPOSE OF REVIEW

Cataract surgery in the setting of small pupil represent a major challenge and it is associated with a higher risk of complications. When pharmacologic pupil dilation fails, mechanical pupil expansion devices are needed to obtain and maintain sufficient intraoperative mydriasis. The purpose of this review is to assess the pupil expansion devices currently available.

RECENT FINDINGS

A variety of pupil expansion devices are offered on the market. They differ for design, material, shape, size, cost, and easiness of insertion/removal, nonetheless they all seem to be effective in improving the pupil size and easing the cataract surgery.

SUMMARY

Mechanical pupil expansion can be effectively achieved with a variety of devices, which are well tolerated and can facilitate cataract surgery in the setting of poor mydriasis.

Femtosecond laser-assisted cataract surgery in small pupils using non-aligned iris expansion ring without viscoelastic and corneal suture

PURPOSE

To describe a technique for cataract surgery in eyes with small pupils that combines the use of the femtosecond laser and an iris expansion device, but without the use of corneal sutures and an ophthalmic viscosurgical device (OVD) at the time of laser application.

METHODS

A retrospective case series of three eyes with small pupils were operated by the same surgeon without a corneal suture and with removal of anterior chamber OVD prior to laser application.

RESULTS

Corrected distance visual acuity (CDVA) for 1 eye in a 70 year-old patient was 20/70 preoperatively and 20/20 thirty days postoperatively. CDVA for a second patient was 20/50 and 20/200 in the two eyes, which improved to 20/25 two months postoperatively in both eyes. There were no complications observed and the intraocular lens were well-centered.

CONCLUSION

The use of mechanical pupil expander rings is safe and practical in setting small pupils during femtosecond laser-assisted cataract surgery.

[Surgical treatment of hypermature cataract in patients with lens subluxation and small pupil]

Studying the possibilities of hybrid (femtosecond laser-assisted) phacoemulsification in complicated situations is a relevant problem in cataract surgery.

PURPOSE

To develop a technique for hybrid (femtosecond laser-assisted) phacoemulsification in patients with a combination of hypermature cataract, small pupil and lens subluxation.

MATERIAL AND METHODS

Hybrid (femtosecond laser-assisted) phacoemulsification of hypermature cataracts was performed in 36 patients (36 eyes) aged 63 to 78 years with grade I-II lens subluxation in combination with small pupil. The initial circular femtolaser capsulotomy was performed within the small pupil using the VICTUS system (Technolas Perfect Vision, Germany). After dilating the pupil with retractor hooks, the capsulorhexis was manually expanded to the required diameter.

RESULTS

In all cases, the resulting capsulorhexis had a regular round shape with a smooth edge, without radial ruptures. This made it possible to apply modern methods of fixation and centration of the capsular bag in case of lens subluxation and to perform intracapsular implantation of an intraocular lens (IOL). Complete intracapsular fixation of the IOL with optics edge fully covered by the edge of the capsulorhexis in the postoperative period was achieved in 34 (94.4%) cases. In 2 (5.6%) cases in the postoperative period, the edge of the capsulorhexis exceeded the edge of the IOL optics. The loss of corneal endothelial cells 3 months after surgery was 8.8±1.9%.

CONCLUSION

The use of the proposed combined technique of capsulorhexis made it possible to perform the most physiologically appropriate intracapsular IOL implantation in all patients with hypermature cataract, small pupil and lens subluxation.

Corectopia grading: A novel classification system

Objectives: To present and validate the novel grading system for objective classification of corectopia.Subjects and Methods: We evaluated 28 eyes of 28 patients with or without corectopia and validated the grading and classification system for corectopia according to three major criteria: (i) direction, (ii) extent, and (iii) alteration of mydriasis. Intraclass correlation coefficient (ICC) and inter-rater agreement between 7 inexperienced and 1 experienced ophthalmologist against a golden standard (GS) were calculated.Results: The ICC for the 7 inexperienced ophthalmologists regarding the grading of direction and centration of the pupil was 0.83 (95% confidence interval (CI), 0.74 to 0.90; p < .001) and 0.57 (95% CI, 0.43 to 0.72; p < .001), respectively. The inter-rater agreement was the same or almost the same in cases of pupil decentration between the inexperienced, experienced ophthalmologists and the GS (k = 0.82; 95% CI, 0.64-1.00; p < .001). In assessing the direction of pupil displacement, the inter-rater agreement was almost perfect between the inexperienced (k = 0.93; 95% CI, 0.84-1.00; p < .001) and experienced (k = 0.92; 95% CI: 0.82-1.02; p < .001) ophthalmologists and the GS.Conclusion: The first detailed clinical classification is proposed for objective corectopia grading particularly relevant in documenting and assessing progressive disease. It was confirmed to be acceptable for clinical use by inexperienced and experienced ophthalmologists alike.

A Novel Sequential Docking Technique: Use of Femtosecond Arcuate Keratotomy and Femtosecond Assisted Cataract Surgery Using a Pupil Expansion Ring on a Patient with Intraoperative Floppy Iris Syndrome

Purpose

The purpose of this study was to evaluate the efficacy of a novel double-docking technique, incorporating the use of femtosecond laser arcuate keratotomy (FSAK) in correcting low-degree astigmatism and Malyugin ring, in a patient with intraoperative floppy iris syndrome (IFIS).

Methods

A case report of a 72-year-old man with grade 4 cataract, low-degree astigmatism (<2D), and IFIS (pupil size <4 mm, intraoperatively) is presented. The patient underwent cataract surgery using a femtosecond laser to treat low-degree astigmatism because the patient requested for the use of a multifocal  intraocular lens (IOL). The first docking was performed to complete arcuate keratotomy, produce the mainparacentesis incisions, and create clear corneal incisions. Insertion of the Malyugin ring was performed after the first docking, whereas the second one was executed to complete continuous curvilinear capsulotomy and lens fragmentation. The patient's uncorrected visual acuity (UCVA) was measured pre- and post-operatively. The complications were evaluated post-operatively and 3 months later during the follow-up visit.

Results

The patient's UCVA for distance improved from 0.3 (6/12 Snellen equivalent) to 0 (6/6 Snellen equivalent) logMAR post-operatively. During the follow-up visit, the patient's uncorrected near visual acuity was at J2. His corneal astigmatism changed from -1.0 Diopter @177° pre-operative to -0.12 D @173° post-operative. No other intraoperative or post-operative complications were observed.

Conclusion

The double-docking technique, with the use of FSAK, and Malyugin ring produced successful surgical outcomes for the patient. The benefits of this technique allow surgeons to avoid changing the shape of the patient's cornea from the injection of the viscoelastic device into the anterior chamber, which could lower the femtosecond laser's precision and docking location.

Modelling floppy iris syndrome and the impact of pupil size and ring devices on iris displacement

Introduction

The aim of this paper was to further develop a previously described finite element model which equates clinical iris billowing movements with mechanical buckling behaviour, simulating floppy iris syndrome. We wished to evaluate the impact of pupil dilation and mechanical devices on normal iris and floppy iris models.

Methods

Theoretical mathematical modelling and computer simulations were used to assess billowing/buckling patterns of the iris under loading pressures for the undilated and dilated normal iris, the undilated and dilated floppy iris, and additionally with a mechanical ring device.

Results

For the normal iris, billowing/buckling occurred at a critical pressure of 19.92 mmHg for 5 mm pupil size, which increased to 28.00 mmHg (40.56%) with a 7 mm pupil. The Malyugin ring device significantly increased critical initiating buckling pressures in the normal iris scenario, to 34.58 mmHg (73.59%) for 7 mm ring with boundary conditions I (BC I) and 34.51 mmHg (73.24%) with BC II. For the most floppy iris modelling (40% degradation), initiating buckling value was 18.04 mmHg (−9.44%), which increased to 28.39 mmHg (42.52%) with the 7 mm ring. These results were much greater than for normal undilated iris without restrictive mechanical expansion (19.92 mmHg).

Conclusion

This simulation demonstrates that pupil expansion devices inhibit iris billowing even in the setting of floppy iris syndrome. Our work also provides a model to further investigate the impact of pupil size or pharmacological interventions on anterior segment conditions affected by iris position.

Series of cataract surgeries with I-ring pupil expansion ring

BACKGROUND

The retrospective review of I-ring pupil expansion ring use is designed to examine the patient characteristics and associated surgical challenges in a clinical practice. The hypothesis is that I-ring provides a necessary additive tool in dealing with challenging cataract surgeries with small pupils.

AIM

To document the safety profile and use of I-ring pupil expansion ring in a clinical practice.

METHODS

A retrospective chart review of 12 consecutive cases within the same year (2016) of cataract surgeries employing I-ring pupil expansion ring (Beaver-Visitec, International) by a single surgeon at the same ambulatory surgical center was conducted. Demographic, pre-op, intra-op, and post-op data were recorded. Total number of cataract cases performed was also recorded.

RESULTS

8 of 12 cases were planned I-ring cases. 1 case was decided intraoperatively when femtosecond laser caused the pupil to shrink. The other 3 cases were also decided upon intraoperatively when pupil was deemed to be small. 7 patients had IFIS from Flomax use. 2 patients had pseudoexfoliation syndrome as the cause of small pupil. 2 patients had narrow angles with brunescent cataracts. 2 patients had pre-op partial zonular dehiscence. 1 patient had 360^o of posterior synechiae. 2 cases had ruptured posterior capsule that required anterior vitrectomy. No complications were attributed to the pupil expansion ring. A total of 296 cataract surgeries were performed that year by the surgeon, making the rate of pupil ring use 4.1%.

CONCLUSION

Small pupil requiring pupil expansion ring during cataract surgery is often associated with other challenges, such as brunescent cataract, zonular weakness, and posterior synechiae in this series. I-ring helped to reduce at least one challenge in these difficult cases.

[Mechanical dilation of the pupil and its possible applications in femtosecond laser-assisted cataract surgery]

In certain cases intraoperative pupil dilation during cataract surgery may be necessary to improve the visualization of intraocular structures and assure the atraumatic nature of surgical manipulations. The article reviews a wide range of pupil expanders, their historical aspects and possibilities of their application in modern cataract surgery.

Cataract surgery in small pupils

This paper presents the review of historical aspects and the current state-of-the-art in various pupil dilatation methods to be used in cataract surgery. The surgical algorithm in managing small pupil cases should include topical and intraocular mydriatics, appropriately selected viscosurgical device and mechanical dilatation with instruments, iris hooks, and/or pupil expanders.

Recent advances in small pupil cataract surgery

PURPOSE OF REVIEW

To highlight the existing and emerging cataract surgery trends in patients with insufficient mydriasis. Discuss the latest pharmacological approaches for pre and intraoperative pupil dilatation. Present the variety of newest pupil expansion devices; critically review their advantages and possible limitations to be considered by the surgeon.

RECENT FINDINGS

The intracameral use of various mydriatic combinations augmenting the preoperative mydriatic instillations is currently gaining popularity in cataract surgery. Two main options are available: bolus injection of pharmacological agent or its constant irrigation during the phacoemulsification procedure. The former is aimed to expand the pupil, whereas the latter is mostly preventing the pupil from constriction. Introduction of femtosecond-assisted cataract surgery, apart from some benefits was followed by a variety of adverse effects including prostaglandin release into the aqueous humor causing pupil constriction. Preoperative administration of nonsteroidal anti-inflammatory drugs at least 1 day prior to surgery significantly decreases the chance of pupil constriction after laser energy is applied to the eye. However, pupil expansion devices may be needed in up to 10% of cases. Following the success of the Malyugin ring (MicroSurgical Technology Inc., Redmond, Washington, USA) several manufacturers introduced pupil expansion devices of various designs. They are differing with materials, pupillary margin fixation mechanisms, and easiness of manipulations during implantation and removal.

SUMMARY

Combination of proper use of pre and intraoperative pharmacological pupil dilatation protocols combined with pupil expander rings allow for well tolerated and effective cataract surgery in the vast majority of patients with insufficient mydriasis.

Current and effective advantages of femto phacoemulsification

PURPOSE OF REVIEW

The purpose is to review the current and effective advantages of femtosecond laser-assisted cataract surgery (FLACS).

RECENT FINDINGS

FLACS has advantages over manual phacoemulsification in its precision, and predictability and may be especially advantageous in difficult situations such as shallow anterior chamber, subluxated cataracts, white cataracts, and so on. However, the femtosecond capsulorhexis may not be as strong as a manual rhexis. Laser-induced miosis is also a potential disadvantage.

SUMMARY

There may be increased surgeon confidence and patient satisfaction with FLACS and it may be friendlier to the internal structures of the eye. However, it is not superior to manual phacoemulsification in terms of primary outcomes such as visual and refractive outcomes or overall complications. Further refinements in technology may be needed to give it distinct advantages over manual phacoemulsification and to make it the norm in cataract surgery.