Single-action implantation of a 3-piece acrylic intraocular lens with an injector

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.

Early intraocular lens explantations: 10-year database analysis

BACKGROUND

The aim of this study was to analyze the causes and characteristics of IOL explantation within the first year after primary implantation.

METHODS

In this retrospective, cross sectional database study, a database consisting of over 2500 IOL explants sent from 199 national and international doctors over the past 10 years was analyzed. All IOLs explanted within the first year after implantation were included in this analysis. Explants with insufficient information as well as phakic and Add-on IOLs were excluded. Main outcome measures were the reason for explantation, the time between implantation and explantation, as well as IOLs' and patients' characteristics. Additionally, the explanted IOLs were microscopically and histologically analyzed, as required.

RESULTS

Of all explanted IOLs from the database, 1.9% (n = 50) were explanted within the first year after implantation. The most frequent reasons for early IOL explantation were IOL dislocation (32%), visual intolerance (26%), opacification (20%), and intraoperative complications (16%). The time between implantation and explantation was the shortest in cases with intraoperative complications (1.5 ± 3.1 days), followed by IOL dislocation (90.9 ± 103.9 days), visual intolerance (98.3 ± 86.5 days), opacifications (253.5 ± 124.0 days) and other indications (249.7 ± 124.0 days). Calcification of hydrophilic IOLs was the main type of opacification (80%). Notably, seven IOLs required immediate intraoperative exchange due to an intraoperative crack in the optic or a torn off haptic.

CONCLUSION

Indications for early IOL explantation were IOL dislocation, visual intolerance, opacification, and intraoperative complications. Especially intraoperative damages to the IOL and early calcification show a potential for improvement of affected IOLs and implantation systems.

Preparation and evaluation of a lubricious treated cartridge used for implantation of intraocular lenses

In the last decades, many surface modification technologies have been developed in an attempt to improve the function of medical device surfaces by adding or enhancing surface characteristics. These value-added processes included treatment to affect lubricity, hemocompatibility and drug delivery. A unique hydrophilic, lubricious coating was developed to treat hydrophobic polymer surfaces. The coating platforms described are composed of a polyelectrolyte molecular film containing hydrophilic, lubricant molecules. The molecular film is then further cross-linked with di-functional aldehyde molecules to form an interpenetrating network (IPN). The IPN entraps lubricant molecules in the matrix and provides for prolonged stability of the lubricity. This coating was applied to cartridges which were used to deliver intraocular lenses (IOLs) that replaced the cataractous crystalline lenses in patients In order to determine the safety and effectiveness of the coating, a rabbit in vivo study was designed to evaluate the ease of implantation and postoperative response to implantation of the foldable acrylic IOLs. The performance evaluation of the lubricious treated cartridges focused on the ease of insertion and post-IOL implantation response. It was found that the UNFOLDER Emerald Insertion System (Advanced Medical Optics) with lubricious treated cartridges generally required lower insertion forces than the standard UNFOLDER Emerald cartridges. The postoperative inflammatory response following lens extraction and posterior chamber implantation of low (6D), medium (20D) and high (30D) diopter foldable acrylic IOLs with both treated and standard cartridges was mild. Inflammation generally resolved by 3 weeks. Thus, in this animal study, the coating was shown to be effective in assisting the delivery of IOLs through cartridges, without causing any adverse effects.

Incision sizes at different stages of phacoemulsification with foldable intraocular lens implantation

PURPOSE

To evaluate incision sizes during different stages of phacoemulsification and after implantation of a foldable acrylic intraocular lens (IOL).

SETTING

Private eye center, Manila, Philippines.

METHODS

In this prospective observational case series, incision widths were measured before and after microcoaxial phacoemulsification (2.2 mm), after cortical removal, and after implantation of a 6.0 mm optic, foldable, single-piece aspheric hydrophobic acrylic IOL using a D cartridge and a Monarch III injector.

RESULTS

The incision width increased in 101 (93.5%) of the 108 eyes; the enlargement was 0.1 mm in 78 eyes (77.2%) and 0.2 mm in 23 eyes (22.8%). The final incision width was 2.3 mm in 78 eyes (72.2%), 2.2 mm in 27 eyes (25.0%), 2.1 mm in 2 eyes, and 2.4 mm in 1 eye. Enlargement occurred during phacoemulsification in 39 eyes, during cortical removal in 33 eyes, and during IOL implantation in 52 eyes; 23 eyes had more than 1 enlargement. Before IOL implantation, the incision was smaller than 2.2 mm in 76 eyes (70.4%); after IOL implantation, the incision increased to 2.3 mm in 47 eyes (61.8%). Thirty-two eyes (29.6%) had a 2.3 mm incision before IOL implantation; the incision increased further (by 0.1 mm) after IOL implantation in 1 eye.

CONCLUSIONS

Incision enlargement occurred at different stages of phacoemulsification, mostly during IOL implantation. More than 72% of eyes had a final incision of 2.3 mm. Beginning with a 2.3 mm incision may prevent wound tears and surface irregularities.

Clinical presentation of intraocular lens schisis

PURPOSE

To analyze the clinical presentation and implications of cavity or schisis formation in the MemoryLens (CIBA Vision) intraocular lens (IOL) optic.

SETTING

Eye Department, Red Cross Hospital, Munich, Germany.

METHODS

This study was a retrospective chart review and slitlamp photography analysis of IOL schisis.

RESULTS

Four patients with IOL schisis were identified and their charts analyzed. Clinically, the schisis presented as a sharply demarcated round structure. The aspect was clear on coaxial illumination, but on tangential illumination the schisis area was opaque. Patients experienced glare, foggy vision, and deteriorated visual function or had no symptoms. One patient lost visual acuity, and the IOL was explanted.

CONCLUSIONS

Clinically, IOL schisis was easily differentiated from cases of IOL opacification due to calcification. The clinical implication was not uniform, ranging from no symptoms to great visual disturbance leading to explantation of the IOL. The cause of this complication remains unclear. A possible explanation is the impact of solvent-induced tensile stress on the IOL optic material during the manufacturing process.