Objective
To evaluate the delivery characteristics of the AcrySof IQ SN60WS intraocular lens (IOL) injected via a preloaded AcrySert delivery system.
Design
Prospective observational case series.
Methods
setting : This study was carried out in the cataract service of an ophthalmic hospital that serves a large sector of inner-city London. patient population : The study included all patients undergoing routine phacoemulsification procedures with implantation of the SN60WS IOL via the preloaded system over 5 consecutive months. A total of 85 patients (85 eyes) were included in this study. intervention : Phacoemulsification procedures conducted by 7 surgeons were digitally captured. outcome measures : Video recordings of the IOL delivery stage were analyzed by a single observer. Of particular interests were the orientation of the leading haptic and optic on insertion, the degree of intrawound manipulation of the injector, and the time required to satisfactorily deliver the IOL into the capsular bag in a correct orientation. Problems of IOL delivery were also noted.
Results
In 38 out of 85 eyes (45%), correct IOL delivery behavior was achieved with the leading haptic orientating to the left of the surgeon and thus did not require any intrawound rotational manipulation of the injector. Forty-seven of the 85 eyes (55%) required additional rotational manipulation of IOL orientation. Other problems recorded were trapped trailing haptic, haptic-optic adhesion, overriding of the plunger over the optic, and trauma to optic edge. The average time to achieve satisfactory IOL position was 47 seconds. IOL power and the grade of the operating surgeon did not appear to influence the event of a misdirected leading haptic.
Conclusions
The AcrySof SN60WS/AcrySert system does not appear to meet the expectations of pro-viding a predictable means of IOL delivery.
With continual advances in modern cataract surgery, development of safe, effective, and predictable mechanisms of intraocular lens (IOL) delivery through increasingly smaller incisions remains a constant challenge.
Perceived benefits of small incisions include shorter duration of wound healing and recovery, less wound-induced postoperative astigmatism, and lower risk of infection by reduction of micro-organism access in the early postoperative period.
Incision enlargement generally occurs at the IOL implantation stage of phacoemulsification. Smaller incisions are now made possible with the declining trend of using forceps to insert rigid polymethyl methacrylate lenses and the more frequent use of soft silicone or acrylic lenses, which are folded and injected into the eye. In addition to the IOL material and design, the advent of injectable IOL delivery systems of such soft silicone or acrylic lenses has also been key in the progress made to date.
A further advancement of injectable IOLs is the development of preloaded injectable IOL delivery systems. The perceived benefits of this novel system include the elimination of the IOL injector loading variability seen in non-preloaded systems, avoidance of potential loading error, and reduced surgical time.
In this study, we observed the delivery characteristics of one of the first preloaded injectable IOL delivery systems to reach market, AcrySert (Alcon Universal Ltd, Hunenberg, Switzerland), for the single-piece AcrySof IQ Aspheric IOL SN60WS (Alcon Surgical Inc, Forth Worth, Texas, USA). This observational study aims to assess the delivery characteristics and the predictability of this particular IOL delivery system.
Methods
The AcrySof IQ SN60WS is a single-piece 6-mm hydrophobic acrylic IOL. It is preloaded and delivered via the Alcon AcrySert injector system. This prospective observational study was carried out in the setting of the cataract service at Moorfields Eye Hospital, a UK National Health Service hospital that serves a large sector of inner-city and east London. At the time of the study, the preloaded SN60WS system was the standard lens used by the cataract service for uncomplicated cataract surgery. The study was conducted respecting the principles of the Helsinki Declaration and good clinical practice. It was approved by the Moorfields Eye Hospital audit and clinical governance department.
All patients undergoing routine phacoemulsification procedure on the same surgical list over 5 consecutive months were included in the study. Patients were included only if phacoemulsification was routine and uncomplicated with an intact rhexis and the desired IOL power was in the range available by the manufacturer. Topically anesthetized phacoemulsification procedures conducted by 7 surgeons with varying levels of ophthalmic surgical experience (consultants, fellows, and ophthalmic residents) were digitally captured and analyzed by a single observer. The analysis focused on the intraocular delivery stage of the IOL itself. None of the eyes studied had previously undergone intraocular surgery.
The AcrySert containing the AcrySof IQ SN60WS IOL was prepared by the assisting scrub nurse and primed with hydroxypropyl methylcellulose as per manufacturer’s instructions. The surgeon would advance the IOL in the injector to the point that it was appropriate to introduce it into the main surgical wound, with the IOL still within the cartridge nozzle in its entirety. The main clear corneal wound, created with a 3.2-mm keratome at the start of cataract surgery, was used to deliver the IOL into the eye. With the tip of the injector within the surgical wound and its bevel opening in the anterior chamber, delivery of the IOL was achieved through further advancement of the IOL. The aim was firstly to get the leading haptic into the capsular bag. The trailing haptic was then dialed into the bag with a second manipulating instrument to achieve a centered IOL position. The time taken from the moment the injector was introduced into the main surgical wound to the final IOL manipulation to satisfactorily position the IOL in the capsular bag was recorded.
Analyses were made from video recordings of the IOL insertion by a single observer who was masked to the identity of the patient and operating surgeon. Of particular interest were the orientation of the leading haptic and optic on insertion and the degree of intrawound manipulation of the injector required to satisfactorily deliver the IOL into the capsular bag in a correct orientation. Problems of IOL delivery, including entrapment of trailing haptic, haptic-optic adhesion, overriding of the syringe plunger over the optic, and trauma to the optic edge, were also noted.
Results
A total of 85 topically anesthetized phacoemulsification procedures were included and video recordings evaluated. The mean age at the time of surgery was 73.1 ± 9.97 years. There were 44 male and 41 female patients.
IOL powers of the AcrySof IQ SN60WS inserted ranged from +16.0 to +29.5 diopters. The average time taken to achieve satisfactory capsular bag IOL position was 47 seconds.
The correct IOL delivery behavior should result in the leading haptic orientating to the left of the surgeon as the optic is advanced with the trailing haptic following, unhindered by the injector plunger. Thirty-eight out of 85 IOL deliveries did not require any intrawound rotation of the injector. In these cases the leading haptic was correctly orientated to the left, followed by the optic, with uneventful delivery of the trailing haptic ( Figure 1 , Left).
Incorrect Presentation of Leading Haptic
In 34 out of 85 IOL deliveries, the leading haptic presented into the anterior chamber incorrectly orientated to the right, requiring a 180-degree rotation of the injector in the wound in order to correct the misdirection ( Figure 1 , Center and Right). This maneuver was performed while simultaneously advancing the IOL in order to achieve a correct orientation of both the leading haptic and optic into the capsular bag. In 4 of these cases, the IOL orientation could not be correctly retrieved, resulting in the final IOL position having “flipped” 180 degrees.
In 13 out of 85 IOL deliveries, the leading haptic was orientated vertically downwards in the bag, requiring injector rotation in order to orientate the haptic satisfactorily to the left so as to avoid a “twisted” haptic as the optic is advanced. In 1 of these cases, the situation could not be retrieved by the surgeon, resulting in a “flipped” IOL outcome.
Trapped Trailing Haptic
In 6 out of 85 IOL deliveries, the trailing haptic became trapped in the nozzle, between the syringe plunger and the nozzle ( Figure 2 , Left). In 5 of these, the haptic became free with further manipulation of the plunger only. In 1 case, the assistance of additional intrawound instrumentation was required with the distal haptic and optic already within the anterior chamber. In 2 of these 6 cases, the trailing haptics remained within and partly external to the surgical wound after release, requiring instrumentation to reposition the haptic intraocularly. The outcome of 1 other trapped trailing haptic was a “flipped” IOL position.
