Future Intraocular Lens Technologies.

The future of intraocular lens (IOL) technology has already begun with a number of recent innovations. The postoperative change of refractive power will lead to a customized fine-tuning that provides patients with the individual vision they expect and with as much spectacle independence as possible. The latest-generation (2.0) Light-Adjustable Lens (RxSight) was recently introduced into clinical practice, with the first results being very encouraging. Other methods of altering the power of an already implanted IOL are under development. The same can be said about the correction of presbyopia, the so-called last frontier in refractive surgery. Extended depth-of-focus IOLs have been introduced, as has the technology of the pinhole IOL. The latter has therapeutic potential beyond the refractive aspect and has already proven helpful in cases of iris defects and irregular corneas. Several technologies are currently being tested to achieve-finally-an accommodative IOL. One such concept uses the (remaining) strength of the ciliary muscle, whereas another is triggered by the pupil reaction when shifting focus from far to near. Not an IOL itself, but rather a high-tech innovation that so far has mostly been implanted during cataract surgery, is a microelectronic sensor that measures habitual intraocular pressure (IOP) at any given time and promises to revolutionize the management of glaucoma patients. The last generation of this device (Eyemate; Implandata Opthalmics Products GmbH) is implanted during small-incision cataract surgery; the latest development is an even smaller sensor that will be inserted suprachoroidally before, in the near future, such a device will be part of a capsular ring. These IOP sensors are a prime example that IOL technology will continue to be a driving force in ophthalmology, with a positive impact far beyond cataract surgery.

[Intraocular Lens as a Drug Delivery Device: State of the Art and Future Perspective]. / Die Intraokularlinse als Arzneimittelträger: Stand der Forschung und Ausblick.

Development of an intraocular lens (IOL) as a drug delivery device has been pursued for many years and is a promising concept in modern cataract surgery. Common postoperative conditions such as posterior capsule opacification (PCO), intraocular inflammation or the rare but severe complications of cataract surgery like endophthalmitis are potential therapeutic targets for a drug-eluting IOL. There are three techniques of pharmacological IOL modification: Firstly, surface modification of the IOL ("coating"); secondly, IOL optic modification ("soaking") and lastly, loading the IOL haptics with a slow release system. The last option does not interfere with the IOL optics at all. Therefore, a broad spectrum of pharmacological agents needs to be assessed in preclinical and clinical studies to determine which agent/IOL combination is safe and efficient. For pharmacological PCO prophylaxis, erufosine-loaded IOLs are of great clinical interest. Heparin-coated IOLs might become clinically relevant for attenuation of intraocular inflammation after cataract surgery and cefuroxime-loaded IOLs for endophthalmitis prophylaxis.

[Aberrometry results of a new IOL model with variable refractive surface].

The article presents the aberrometry results of a new intraocular lens (IOL) model with variable refractive surface of own design. By changing the pressure of silicone oil inside the artificial lens three levels of refractive power were achieved: 17.5D; 20.0D; 22.0D. The quality of the experimental optical system is comparable to that of a human eye after in vivo implantation of a ReSTOR multifocal IOL. Accommodating IOLs with refractive power varying within 4.5D are capable of maintaining the quality of retinal image, thus, ensuring high visual acuity.

Halos y lentes intraoculares multifocales: origen e interpretación / Halos and multifocal intraocular lenses: Origin and interpretation

OBJETIVO: Caracterización teórica y experimental del halo en lentes intraoculares (LIO) multifocales. MÉTODO: El halo producido por una LIO multifocal (LIOM) se origina cuando sobre una imagen enfocada se superpone otra desenfocada. Mediante óptica geométrica se demuestra que el diámetro de cada halo depende de la adición de la lente (ΔP), de la potencia base (Pd) y del diámetro de la lente iluminada que contribuye al foco «no-enfocado». En plano imagen que corresponde al foco de lejos, el diámetro del halo (δHd) viene dado por: δHd = dpn ΔP/Pd donde dpn es el diámetro de la LIO que contribuye al foco cercano. Análogamente, en el plano imagen del foco de cerca del diámetro del halo (δHn) viene dado por δHn = dpd ΔP/Pd, donde dpd es el diámetro de LIO que contribuye al foco lejano. Los pacientes perciben halos cuando observan objetos luminosos sobre un fondo relativamente oscuro. In vitro, el halo se puede caracterizar analizando el perfil de intensidad de la imagen de un pinhole que forma cada uno de los focos de una lente multifocal. RESULTADOS Y CONCLUSIONES: Hemos comparado los halos producidos por varias LIOM de la misma potencia base (20 D) en un banco óptico. Tal y como predice la teoría, cuanto mayor es la adición de la LIOM de diseños asféricos (SN6AD3 vs. ZMA00), las lentes apodizadas presentan un halo de menor diámetro que las no-apodizadas en visión lejana, mientras que en visión cercana el halo es del mismo tamaño pero la intensidad relativa es mayor en el caso de las apodizadas. Comparando lentes esféricas y asféricas con igual diseño difractivo (SN60D3 vs. SN6AD3) el halo en visión lejana en la lente esférica es mayor, mientras que en visión cercana la lente esférica produce un halo de menor tamaño pero de mayor intensidad debido a la aberración esférica del foco lejano en el plano imagen del foco cercano. En el caso de una lente trifocal (AT LISA 839MP) la característica más distintiva es la aparición de un doble halo debido a los focos lejano e intermedio de la LIO, sobre la imagen enfocada en visión cercana

OBJECTIVE: To present the theoretical and experimental characterization of the halo in multifocal intraocular lenses (MIOL). METHOD: The origin of the halo in a MIOL is the overlaying of 2 or more images. Using geometrical optics, it can be demonstrated that the diameter of each halo depends on the addition of the lens (ΔP), the base power (Pd), and the diameter of the IOL that contributes to the «non-focused» focus. In the image plane that corresponds to the distance focus, the halo diameter (δHd) is given by: δHd = dpn ΔP/Pd, where dpn is the diameter of the IOL that contributes to the near focus. Analogously, in the near image plane the halo diameter (δHn) is: δHn = dpd ΔP/Pd, where dpd is the diameter of the IOL that contributes to the distance focus. Patients perceive halos when they see bright objects over a relatively dark background. In vitro, the halo can be characterized by analyzing the intensity profile of the image of a pinhole that is focused by each of the foci of a MIOL. RESULTS AND CONCLUSIONS: A comparison has been made between the halos induced by different MIOL of the same base power (20D) in an optical bench. As predicted by theory, the larger the addition of the MIOL, the larger the halo diameter. For large pupils and with MIOL with similar aspheric designs and addition (SN6AD3 vs ZMA00), the apodized MIOL has a smaller halo diameter than a non-apodized one in distance vision, while in near vision the size is very similar, but the relative intensity is higher in the apodized MIOL. When comparing lenses with the same diffractive design, but with different spherical-aspheric base design (SN60D3 vs SN6AD3), the halo in distance vision of the spherical MIOL is larger, while in near vision the spherical IOL induces a smaller halo, but with higher intensity due to the spherical aberration of the distance focus in the near image. In the case of a trifocal-diffractive IOL (AT LISA 839MP) the most noticeable characteristic is the double-halo formation due to the 2 non-focused powers

Toric intraocular lenses: historical overview, patient selection, IOL calculation, surgical techniques, clinical outcomes, and complications.

We present an overview of currently available toric intraocular lenses (IOLs) and multifocal toric IOLs. Relevant patient selection criteria, IOL calculation issues, and surgical techniques for IOL implantation are discussed. Clinical outcomes including uncorrected visual acuity, residual refractive astigmatism, and spectacle independency, which have been reported for both toric IOLs and multifocal toric IOLs, are reviewed. The incidence of misalignment, the most important complication of toric IOLs, is determined. Finally, future developments in the field of toric IOLs are discussed.

[Current state of the "light-adjustable lens"]. / Aktueller Stand "light-adjustable lens"

The light-adjustable intraocular lens offers the possibility to correct postoperative residual refractive errors in a non-invasive way. After implantation and healing, a fine-tuning of the refractive power can be performed using ultraviolet light based on the individual requirements of each patient. Up to 2 diopters in sphere, as well as cylinder, can be adjusted in one step. This technology received CE market approval in 2007. This review article summarises published prospective studies on clinical evaluations of the effectiveness, safety and long-term refractive stability of this innovative technique. Moreover, a critical statement about limitations and perspectives will be given and future options will be discussed. For safety reasons, following application of the UV-light during refractive adjustments, examinations of endothelial cell count changes and measurements of corneal thickness have been monitored for 12 months following treatment. Further studies have been performed to evaluate the refractive stability over an 18-month period with a patient population that included average as well as biometrically short and long eyes. An analysis of postoperative refractive data led to optimised constants for preoperative IOL power calculation enabling the surgeon to further enhance visual outcomes with the IOL by using additional nomograms for customised correction of presbyopia, multifocality and increasing depth of focus with individual corrections of asphericity.

Intraocular lenses for presbyopia correction: past, present, and future.

PURPOSE OF REVIEW: To discuss the development of presbyopia-correcting intraocular lenses (IOLs), what we have learned since their introduction a few decades ago, what are the options currently on the market, and where the technology is heading in the future. RECENT FINDINGS: Multifocal and accommodating IOLs have gone through several modifications to improve distance, intermediate and near vision compared to their predecessors. These modifications have also targeted unwanted side-effects such as glare and halos in the multifocal lenses and inconsistent near-vision results in the accommodating IOLs and although the results have improved, they are far from perfect. Therefore, careful patient selection for each of these technologies is crucial for success and patient satisfaction. SUMMARY: Presbyopia correction remains a great challenge in cataract and refractive surgery. In this article, we review the development of presbyopia-correcting IOLs, starting from the simple, two-zone, multifocal, refractive models introduced 2 decades ago, the current Food and Drug Administration (FDA) approved multifocal and accommodating lenses as well as those undergoing FDA trials and take a look into developing technologies that may be available to us in the future.

Glaucoma agudo por bloqueo pupilar secundario a luxación posterior de lente acrílica intraocular tras capsulotomia Nd: YAG / Pupillary block acute glaucoma due to acrylic intraocular lens posterior dislocation AFTER Nd: YAG capsulotomy

Caso clínico: Se describe el caso clínico de una mujer de 68 años que presentó un glaucoma agudo secundario a un bloqueo pupilar por herniación vítrea a cámara anterior tras luxación de la lente intraocular a cámara vítrea un mes después de capsulotomía Nd:YAG.DiscusiónSe debe considerar este cuadro clínico en el diagnóstico diferencial del glaucoma agudo seudofáquico, especialmente si existe el antecedente de capsulotomía Nd:YAG y el edema corneal impide una correcta visualización de la cámara anterior (AU)

Case report: We present the clinical case of a 68 year-old woman who developed a pupillary block acute glaucoma due to vitreous hernia into anterior chamber following posterior dislocation of the intraocular lens one month after an Nd:YAG capsulotomy.DiscussionWe should consider these symptoms in the differential diagnosis of pseudophakic acute glaucoma, especially when visualisation of the anterior chamber is difficult due to corneal oedema and Nd:YAG capsulotomy was done (AU)

The world through a lens: the vision of Sir Harold Ridley.

Sir Harold Ridley is recognised today as the inventor of intraocular lens implantation, one the most successful and common procedures in all of surgery. His story, however, is not largely one of triumph and public accolade. This paper reviews Ridley's invention of the intraocular lens and highlights the struggles he faced after his discovery.

Cataract and refractive surgery in ; a survey of KSCRS members from 1995~2006.

PURPOSE: This purpose of this report was to study trends in cataract and refractive surgeries conducted during the past twelve years and to compare results to previous reports from the ASCRS and New Zealand (NZ) in order to forecast future medical services. METHODS: We surveyed members of the Korean Society of Cataract and Refractive Surgery (KSCRS) every year from 1995 to 2006, and studied changes in cataract and refractive surgeries (RS). RESULTS: The duration of hospitalization has been gradually decreasing to the point that a one day hospitalization following surgery has become common. The rate of topical anesthesia use has significantly increased since 1998. Sutureless incision methods are now commonly practiced. The use of acryl IOL as an optic material has been gradually increasing for cataract surgeries. KSCRS members showed an interest in the special intraocular lenses as multifocal IOL. While Excimer laser PRK was the most popular refractive surgery during the first stage, KSCRS members increasingly prefer LASIK to the Excimer laser PRK. Regression of the corrected visual acuity, dry eye, night halo, and flashes were the most common complications following refractive surgeries. Medical disputes related to PRK and LASIK have been gradually increasing throughout the study period. CONCLUSIONS: We confirm that the KSCRS practice styles for cataract and RS are similar to those of the ASCRS and NZ. We infer a world-wide trend from the comparison of these three societies.

Advances in cataract surgery and intraocular lenses.

Cataract surgery is one of the most common medical procedures among persons age 65 and older. Once an inpatient procedure, it has become a simple outpatient surgery with extremely low rates of morbidity. With the development of implantable intraocular lenses (IOLs), patients undergoing cataract surgery gained the benefit of corrected pre-existing refractive error, astigmatism, and presbyopia. This article reviews developments in cataract surgery and describes current IOL technology.