Folding procedure for acrylic intraocular lenses

Characterisation of Intraocular Lens Injectors

In modern ophthalmic surgery, an intraocular lens (IOL) is commonly implanted into the patient's eye with an IOL injector. Many injectors are available, showing various technological differences, from the early manually loaded injector systems to the modern preloaded injectors. This review aims to give a concise overview of the defining characteristics of injector models and draws attention to complications that may occur during IOL implantation. One can differentiate injectors according to their preoperative preparation (manually loaded or preloaded), their implantation mechanism (push-type or screw-type or combined or automated), the size of the nozzle tip, the presence of an insertion depth control feature, and the injector's reusability. Potential complications are IOL misconfigurations such as a haptic-optic adhesion, adherence of the IOL to the injector plunger, an overriding plunger, uncontrolled IOL rotation, a trapped trailing haptic, or damage to the IOL. Additionally, during IOL implantation, the nozzle can become damaged with scratches, extensions, cracks, or bursts to the tip. While these complications rarely produce long-term consequences, manufacturers should try to prevent them by further improving their devices. Similarly, surgeons should evaluate new injectors carefully to ensure the highest possible surgical safety.

Innovative intraocular lens loading magnified

Cataract surgery continues to evolve and advance in terms of new technology and improved techniques, offering a final result of better visual quality and faster visual recovery for our patients. Intraocular lens (IOL) delivery into the eye is a critical step in cataract surgery. Currently, eye surgeons load the IOL into the cartridge under the operating microscope or ophthalmic assistants load the IOL under their own direct vision. Because ophthalmic assistants load the IOL unaided, the IOL may be mishandled and lead to challenges such as IOL slippage, breakage, or incorrect orientation. In order to overcome these challenges and facilitate the surgical process, here we describe a novel technique by introducing a magnifier to the surgical table to aid ophthalmic assistants during this crucial step in cataract surgery. This not only saves time but also improves precision while loading IOL into the cartridge during cataract surgery.

Clinical outcomes of combined pars plana vitrectomy and trans-scleral 4-point suture fixation of a foldable intraocular lens

OBJECTIVE

To describe outcomes of combined pars plana vitrectomy (PPV) and trans-scleral 4-point suture fixation of a foldable Akreos AO60 intraocular lens (IOL) in eyes with subluxated or dislocated lens or IOL.

METHODS

Retrospective case series of 20 eyes of 18 patients who underwent this procedure with a minimum follow-up of 3 months. Outcome measures included final best-corrected Snellen visual acuity (BCVA), spherical equivalent (SE) and intraoperative and postoperative complications.

RESULTS

Mean age at surgery was 43.65 years. The commonest indication for surgery was post-traumatic subluxated or dislocated cataract. Mean BCVA improved from 6/24 preoperatively to 6/9 at final follow-up (p < 0.0001). Mean SE was 5.69 dioptres preoperatively and -1.32 dioptres postoperatively. There were no intraoperative complications. Postoperative complications included transient vitreous haemorrhage in one eye and cystoid macular oedema in one eye. Postoperative Pentacam analysis confirmed the absence of IOL tilt or decentration in six eyes. Mean follow-up was 8.9 months (range 3-30 months).

CONCLUSION

Trans-scleral 4-point suture fixation of a foldable Akreos AO60 IOL can be performed safely along with concurrent PPV across varying surgical indications resulting in a substantial improvement in visual acuity with minimal complications.

An 8-year retrospective study of cataract surgery and postoperative endophthalmitis: injectable intraocular lenses may reduce the incidence of postoperative endophthalmitis

BACKGROUND/AIMS

Postoperative endophthalmitis (POE) is a rare but potentially devastating complication of modern cataract surgery. We examine whether the use of injectable intraocular lenses (IOLs) is associated with a lower rate of POE after cataract surgery compared with forceps-inserted foldable IOLs.

METHODS

A single-centre retrospective cohort study of 25 410 cataract operations was performed over an 8-year period when standard practice in cataract surgery changed from the use of forceps-inserted foldable IOLs to injectable IOLs. Cases of POE were identified and the rates compared between the two groups.

RESULTS

Twelve cases of POE were identified in the study period. The rate of POE was significantly lower in the injectable IOL group compared with the forceps-inserted foldable IOL group (0.008% vs 0.081%, p=0.008). This difference remained significant when controlling for posterior capsular rupture and lens material.

CONCLUSIONS

This study, the largest of its kind to date, supports the use of injectable IOLs over forceps-inserted foldable IOLs as a significant measure in reducing the risk of POE.

[Intraocular lens and bacterial adhesion: influence of the environmental factors, the characteristics of the bacteria, and the target material surface]

Adhesion of bacteria to intraocular lenses is an important step in the pathogenesis of postoperative endophthalmitis. It can be described as a two-phase process including an initial, instantaneous, and reversible phase followed by a time-dependant and irreversible molecular and cellular phase. The binding of bacteria is affected by many factors including environmental factors such as medium composition, presence of proteins and flow conditions, the bacterial cell surface characteristics, and the material's surface properties. This article reviews all these factors affecting the adhesion of bacteria to intraocular lenses. A better understanding of these mechanisms would make it possible to reduce the bacterial adhesion process and thus could help decrease the incidence of postoperative endophthalmitis.

Irregularities on the surface of single-piece AcrySof SA60AT intraocular lenses

PURPOSE

To report a case series of what initially appeared to be macroscopic biomaterial deposits and irregularities on the surface of AcrySof SA60AT intraocular lenses (IOLs) (Alcon Inc.)

SETTING

Department of Ophthalmology and Somerset Hospital, Taunton, United Kingdom; Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, Salt Lake City, Utah, USA; and Intraocular Implant Unit, Sydney Eye Hospital, University of Sydney, Sydney, Australia.

METHODS

Twelve AcrySof SA60AT IOLs were initially thought to have irregularities on their surfaces when examined under the operating microscope before implantation in the capsular bag during cataract surgery. The IOLs were sent for further analysis, including gross examination and light and scanning electron microscopy, to John A. Moran Eye Center, Salt Lake City, Utah, USA, and to Alcon Laboratories, Hemel Hempstead, United Kingdom.

RESULTS

Light microscopy revealed the presence of irregular fine lesions on the IOLs' optics and haptics. The lesions consisted of elevations and depressions of the IOL surface that were present on both the anterior and the posterior surfaces of the IOLs. Scanning electron microscopy confirmed the presence of physical/mechanical damage to the IOLs, which was thought to originate from the packaging. The manufacturer believed this to have resulted from compression of the IOL between the container and its cover.

CONCLUSIONS

Implantation of an imperfect IOL remains a potentially serious occurrence. Faults still occur in modern IOLs, and some defects can be detected by examining the IOL under the operating microscope before implantation into the eye.

Scanning electron microscopic analysis of acrylic intraocular lenses for microincision cataract surgery

PURPOSE

To analyze the surface quality before and after folding of 2 intraocular lens (IOL) models designed for microincision cataract surgery.

SETTING

Eye Clinic and Department of Human Pathology and Oncology, University of Florence, Florence, Italy.

METHODS

Two IOL models now available for sub-2.0 mm microincision were studied: UltraChoice 1.0 Rollable ThinLens (ultrathin lens by ThinOptX) and AcriSmart (foldable lens by AcriTec). Eight IOLs of each model were examined. Scanning electron microscopy (SEM) was performed before and after IOL folding with a dedicated injector. Special attention was given to the optic surface and edges, the optic-haptic junction, and the haptic itself.

RESULTS

Initially, the surface quality of IOLs was evaluated before folding. On SEM, smooth and homogeneous optic and haptic surfaces were revealed in both IOL models with no surplus material or molding flashes; edge finish of all optics showed no evidence of ridges. The IOL surfaces were evaluated after insertion into their injectors and after ejection at room temperature. After folding, the microincision IOLs showed no sign of surface alteration, probably because of their high water content, which makes these IOLs soft and flexible.

CONCLUSIONS

Visual results and long-term biocompatibility of the IOLs are influenced by surface properties. In recent years, there has been a trend toward microincision cataract surgery. Our study shows that the 2 IOL models now available for sub-2.0 mm microincision have acceptable surface properties.