Interlenticular opacification in piggyback AcrySof intraocular lenses: explantation technique and laboratory investigations

[Evolution of IOL exchange. Part 1. Development of methods for IOL exchange]

The review presents the history of development and improvement of methods for intraocular lens (IOL) exchange. Existing techniques of IOL exchange are comparatively analyzed.

A prospective pilot study using a low power piggy-back toric implantable Collamer lens to correct residual refractive error after multifocal IOL implantation

Purpose

To assess whether residual refractive error after in-the-bag multifocal intraocular lens (mIOL) implantation can efficaciously and safely be corrected with a piggy-back low power Visian Toric Implantable Collamer Lens^® (VTICL, STAAR Surgical) placed in the ciliary sulcus.

Patients and methods

Twenty-four eyes of 23 patients (mean age: 57.5 years) with diminished uncorrected distance visual acuity (UDVA) of ≥2 lines due to residual refractive error after mIOL implantation were included in the study. VTICL size was calculated using the standard STAAR Visian ICL calculation software for phakic eyes. Postoperative study visits (1 day, 1 week, 3 months and 6 months after VTICL implantation) included UDVA, corrected distance visual acuity (CDVA), VTICL axis alignment, vault (space between mIOL and VTICL), IOP and documentation of adverse events.

Results

At 6 months, mean UDVA (logMAR) increased from 0.26 preoperatively to −0.01 (P<0.001) while mean CDVA remained unchanged. Mean VTICL misalignment from the preoperative target axis was 5.3° and mean vault was 1385 µm. In the initial phase of the study, 2 VTICL had to be exchanged due to oversizing.

Conclusion

Piggy-back low power VTICL can efficaciously correct residual refractive error after mIOL implantation and significantly increase UDVA. Advantages of this novel surgical approach include: VTICL availability in small diopter steps, no significant surgical-induced astigmatism, atraumatic and reversible procedure.

Clinical and material degradations of intraocular lenses: A review

PURPOSE

To review the published scientific literature concerning clinical and material degradations of intraocular lenses after implantation in cataract surgery.

METHODS

A search was undertaken using the following databases: CENTRAL (including Cochrane Eyes and Vision Trials Register; The Cochrane Library: Issue 2 of 12 February 2019), Ovid MEDLINE (R) without Revisions (1996 to February week 2, 2019), Ovid MEDLINE (R) (1946 to February week 2, 2019), Ovid MEDLINE (R) Daily Update 19 February 2019, MEDLINE and MEDLINE non-indexed items, Embase (1980-2019, week 7), Embase (1974-2019, 19 February), Ovid MEDLINE (R) and Epub Ahead of Print, in-Process & Other Non-Indexed Citations and Daily (1946 to 19 February 2019), Web of Science (all years), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrial.gov) and the WHO International Clinical Trials Registry Platform (www.who.int/ictrp/search/en). Only published articles in English were selected. Search terms/keywords included 'IOL' or 'intraocular lens', combined with 'opacification', degradation, glistenings, nanoglistenings, whitening, transmittance, light scatter, discolouration/discoloration, performance, quality, material, biocompatibility, calcification, explantation and ultraviolet/UV radiation. Relevant in-article references not returned in our searches were also considered.

RESULTS

After review of the available articles, the authors included 122 publications in this review, based on the quality of their methodology and their originality. The studies included in this review were randomized controlled trials, cohort studies, case-controlled studies, case series, case reports, laboratory studies and review papers. Differing material degradations of intraocular lenses have been described and their associated pathophysiology studied. Reported anomalies include photochemical alterations, water vacuoles, internal and surface calcific deposits, surface coatings and discolouration. The nature of such changes has been shown to depend on the type of intraocular lenses material used and/or manufacturing processes and storage conditions employed. Changes in the intraocular lens can also be influenced by surgical technique, coexisting ocular pathologies and topical and systemic medications. The clinical significance of these degradations is variable, with some resulting in significant visual disturbance and the need for intraocular lens explantation and others producing only minimal visual impairments. Failure to recognize the precise nature of the problem may lead to unnecessary laser capsulotomy procedures.

CONCLUSION

Clinical degradations of intraocular lenses are uncommon but have been reported following the implantation of intraocular lenses made of differing biomaterials. Their correct identification and thorough investigation to determine the underlying cause is necessary for optimal patient management and the prevention of such problems. Choosing a lens made of a particular material may be important in patients with certain ocular conditions.

Refractive Results: Safety and Efficacy of Secondary Piggyback Sensar™ AR40 Intraocular Lens Implantation to Correct Pseudophakic Refractive Error

In this study we evaluate the visual outcomes, safety, efficacy, and stability of implanting of second sulcus intraocular lens (IOL) to correct unsatisfied ametropic patients after phacoemulsification. Methods. Retrospective study of 15 eyes (15 patients) underwent secondary intraocular lens implanted into the ciliary sulcus. The IOL used was a Sensar IOL three-piece foldable hydrophobic acrylic IOL. The first IOL in all patients was acrylic intrabagal IOL implanted in uncomplicated phacoemulsification surgery. Results. Fifteen eyes (15 patients) were involved in this study. Preoperatively, mean log⁡MAR UDVA and CDVA were 0.88 ± 0.22 and 0.19 ± 0.13, respectively, with a mean follow-up of 28 months (range: 24 to 36 months). At the end of the follow-up, all eyes achieved log⁡MAR UDVA of 0.20 ± 0.12 with postoperative refraction ranging from 0.00 to −0.50 D of attempted emmetropia. Conclusions. Implantation of the second sulcus SensarAR40 IOL was found to be safe, easy, and simple technique for management of ametropia following uncomplicated phacoemulsification.

Combining primary and piggyback intraocular lenses to treat extreme myopic astigmatism in stable keratoconus following cataract surgery

The majority of those with keratoconus can maximise visual acuity with spectacle or contact lens correction as they age; however, as subjects enter their sixties, cataracts may supervene and contact lens tolerance diminishes with consequent reduction in visual acuity. Following cataract extraction, the complex refractive error associated with keratoconus may not be readily corrected by an intraocular lens alone. This report highlights the planned implantation of a primary posterior chamber toric intraocular lens with a secondary piggyback, sulcus-based, intraocular lens in advanced but stable keratoconus with extreme myopic astigmatism and cataract.

Intraocular lens confusions: a preventable "never event" - The Royal Victorian Eye and Ear Hospital protocol

Intraocular lens (IOL) confusions and errors are among the most common postoperative adverse events. Errors may occur at any stage from the decision to operate to the insertion of the IOL. The most common errors occur during IOL selection pre-operative preparation (anaesthesia given before recognition that the intended IOL is not available), or intraoperatively (wrong IOL implanted because of confusion in the operating room). We review the mechanisms of errors reported in the literature and describe the experience at The Royal Victorian Eye and Ear Hospital. We also describe the implementation of an error-detection protocol and provide qualitative data on its performance.

Refraktive Langzeitergebnisse nach Huckepackimplantation

BACKGROUND

Piggyback lens implantation is an alternative to exchange of the original intraocular lens (IOL) to treat high anisometropia in pseudophakic eyes. We present our results.

PATIENTS AND METHOD

A second IOL (piggyback) was implanted in 27 patients from 2000 to 2006. Nineteen patients were clinically investigated late postoperatively, and data for the other eight patients were evaluated from the patients' files.

RESULTS

The patients were 65+/-9 years old. Follow-up time was 38+/-25 months. The mean preoperative spherical equivalent (SE) in the myopic eyes was -7.86+/-3.82 D and in the hyperopic eyes was 1.64+/-0.74 D. After surgery, the mean SE in the myopic eyes was -1.77+/-1.82 D and in the hyperopic eyes was -0.09+/-0.51 D. Postoperative anisometropia was reduced from 4.64+/-3.3 D. to 0.9+/-0.82 D.

CONCLUSION

Piggyback lens implantation is a safe and effective surgical procedure and is less traumatic than exchange of the original IOL.

Primary piggyback implantation of 3 intraocular lenses in nanophthalmos

We present a patient with bilateral nanophthalmos who had uneventful cataract extraction in the right eye with primary implantation of 3 intraocular lenses (IOLs) of 2 different materials: a 30 diopter (D) acrylic IOL and a 9 D silicone IOL in the capsular bag and a 30 D silicone IOL in the ciliary sulcus. Subsequently, cataract extraction was done in the left eye with bag-sulcus implantation of two 30 D silicone IOLs. The use of 3 IOLs in 1 eye was necessary because the highest available power of acrylic and silicone IOLs at our institution was 30 D. The only short-term complications were temporary corneal edema and partial displacement of the sulcus IOL anterior to the iris in the right eye and bilateral posterior capsule opacification. The late complication of interlenticular opacification was not present 1 year after piggyback IOL implantation.

Bilateral ciliary sulcus implantation of secondary piggyback multifocal intraocular lenses

Ciliary sulcus implantation of secondary multifocal intraocular lenses (IOLs) is an uncommon procedure. We describe a young pseudophakic patient with monofocal IOLs who achieved a high level of satisfaction following bilateral implantation of multifocal IOLs. They were used successfully to correct a residual refractive error for distance vision and to provide spectacle-independence for near vision. Postoperative symptoms such as glare were not problematic.

Synchrony dual-optic accommodating intraocular lens

PURPOSE

To describe a dual-optic accommodating intraocular lens (IOL) based on theoretical considerations.

SETTING

University and independent research group.

METHODS

Ray-tracing analysis using optical modeling software (ZEMAXTM, Focus Software Inc., Tucson, Ariz) in a theoretical model eye was used to analyze lens configurations to optimize the accommodative and magnification effects of axial lens displacement. Finite-element modelling using a commercially available PC-based software package (COSMOS DesignSTAR) was applied to design the biomechanical parameters of the inter-optic articulations and optics.

RESULTS

Ray-tracing analysis indicated that a dual-optic design with a high plus-powered front optic coupled to a minus posterior optic produced greater change in conjugation power of the eye compared to a single-optic intraocular lens and that magnification effects were unlikely to account for improved near vision. Finite-element modelling indicated that the 2 optics can be linked by spring-loaded haptics that allow anterior and posterior axial displacement of the front optic in response to changes in ciliary body tone and capsular tension.

CONCLUSION

A dual-optic design linked by spring haptics increases the accommodative effect of axial optic displacement with minimal magnification effect and has promise for improving the performance of accommodative intraocular lenses.

Optical principles, biomechanics, and initial clinical performance of a dual-optic accommodating intraocular lens (an American Ophthalmological Society thesis)

PURPOSE

To design and develop an accommodating intraocular lens (IOL) for endocapsular fixation with extended accommodative range that can be adapted to current standard extracapsular phacoemulsification technique.

METHODS

Ray tracing analysis and lens design; finite element modeling of biomechanical properties; cadaver eye implantation; initial clinical evaluation.

RESULTS

Ray tracing analysis indicated that a dual-optic design with a high plus-power front optic coupled to an optically compensatory minus posterior optic produced greater change in conjugation power of the eye compared to that produced by axial movement of a single-optic IOL, and that magnification effects were unlikely to account for improved near vision. Finite element modeling indicated that the two optics can be linked by spring-loaded haptics that allow anterior and posterior axial displacement of the front optic in response to changes in ciliary body tone and capsular tension. A dual-optic single-piece foldable silicone lens was constructed based on these principles. Subsequent initial clinical evaluation in 24 human eyes after phacoemulsification for cataract indicated mean 3.22 diopters of accommodation (range, 1 to 5 D) based on defocus curve measurement. Accommodative amplitude evaluation at 1- and 6-month follow-up in all eyes indicated that the accommodative range was maintained and that the lens was well tolerated.

CONCLUSIONS

A dual-optic design increases the accommodative effect of axial optic displacement, with minimal magnification effect. Initial clinical trials suggest that IOLs designed on this principle might provide true pseudophakic accommodation following cataract extraction and lens implantation.

Survey of intraocular lens material and design

Modern cataract surgery is constantly evolving and improving in terms of lens material and design. Researchers and physicians strive to obtain better refractive correction with smaller wound size and minimizing host cell response to limit the proliferation of lens epithelial cells leading to opacification of the lens capsule. Intraocular lens material varies in water content, refractive index, and tensile strength. Intraocular lens design has undergone revisions to prohibit lens epithelial cell migration and reflection of internal and external light. The evolution of intraocular lens and extracapsular cataract surgery has lead to faster postoperative recovery and better visual outcomes.

Errors leading to unexpected pseudophakic ametropia

PURPOSE

Determination of the reasons for clinically significant unplanned ametropia following cataract surgery and the results of management of the ametropia.

METHODS

Retrospective review of 11 consecutive cases of tertiary referral for management of pseudophakic ametropia to the authors. Corrective surgery involved either lens implant exchange or LASIK refractive surgery. Final outcome was assessed by uncorrected and best spectacle corrected visual acuity and manifest refractive outcome.

RESULTS

Five cases (45%) were due to significant error in axial length determination at pre-surgery biometry. Six cases (55%) were due to surgeon or surgical team error, where the surgeon implanted a lens of power at variance with that specified pre-operatively. Nine patients elected to undergo refractive surgery to correct the ametropia and 2 elected to wear a spectacle lens. Seven underwent lens implant exchange and 2 patients underwent LASIK keratorefractive surgery. Eight of nine patients were within 1 dioptre of intended spherical equivalent after refractive surgery and 1 patients was -1.5 dioptre myopic.

CONCLUSIONS

Most cases of serious unintended ametropia after cataract surgery are avoidable. Care should be taken with the biometry and procedural checks to minimise error. When lens implant exchange or LASIK was performed the final refractive results were satisfactory.