Phakic intraocular lenses

Severe pigment dispersion after iris-claw phakic intraocular lens implantation

A 23-year-old female patient presented 3 months after the implantation of an Artisan^® phakic intraocular lens with a severe depigmentation of the iris and peripheral anterior synechiae. Explantation of the intraocular lens and goniosynechialysis were performed. Eleven months after the explantation appearance of the iris significantly improved. There was no loss of lines of corrected distance visual acuity. Severe pigment dispersion after the implantation of an Artisan^® phakic intraocular lens may happen and may require explantation of the lens. Iris depigmentation may improve with time.

Long-term clinical results of posterior chamber phakic intraocular lens implantation to correct myopia

BACKGROUND

The aim of this study was to determine whether implantable collamer lens (ICL) implantation to correct myopia is an effective and safe surgical option even after long-term follow up.

DESIGN

A retrospective observational study was carried out.

PARTICIPANTS

A total of 281 eyes of 145 myopic patients were included in the study.

METHODS

Patients underwent ICL implantation and had the follow-up period of at least 5 years (87 ± 18.9 months).

MAIN OUTCOME MEASURES

Outcome measures included uncorrected and corrected distance visual acuities, refraction for the evaluation of efficacy, safety, stability and predictability, ICL vault and adverse events.

RESULTS

The final mean logMAR uncorrected and corrected distance visual acuities were 0.02 ± 0.19 and -0.12 ± 0.13, respectively. The mean efficacy and safety indices were 1.04 ± 0.32 and 1.20 ± 0.26. The mean spherical equivalent decreased from -8.74 ± 2.27 diopter (D) to -0.58 ± 0.72 D, and there was high predictability with 69.8% and 87.2% having a postoperative refraction within 0.5 D and 1.0 D, respectively. The mean postoperative vault was changed from 2.53 ± 0.6 to 2.00 ± 0.7. Six (2.1%) eyes developed cataract, and the mean endothelial cell loss was 7.8 ± 8.3%. Increased intraocular pressure was found in two (0.7%) eyes that required the exchange of lenses with different sizes.

CONCLUSIONS

Implantable collamer lens implantation to correct myopia was an effective and safe surgery with high predictability and stability during long-term follow up. Slight myopic shift and cataract formation related with change in vault should be further evaluated.

The posterior chamber phakic refractive lens (PRL): a review

Implantation of phakic intraocular lenses (pIOLs) is a reversible refractive procedure, preserving the patient's accommodative function with minimal induction of higher order aberrations compared with corneal photoablative procedures. Despite this, as an intraocular procedure, it has potential risks such as cataracts, chronic uveitis, pupil ovalization, corneal endothelial cell loss, pigmentary dispersion syndrome, pupillary block glaucoma, astigmatism, or endophthalmitis. Currently, only two models of posterior chamber pIOLs are commercially available, the implantable collammer lens (STAAR Surgical Co.) and the phakic refractive lens (PRL; Zeiss Meditec). The number of published reports on the latter is very low, and some concerns still remain about its long-term safety. The present article reviews the published literature on the outcomes after PRL implantation in order to provide a general overview and evaluate its real potential as a surgical refractive option.

Long-term follow-up of first-generation posterior chamber phakic intraocular lens

We present a patient who received a first-generation posterior chamber phakic intraocular lens (PC pIOL) (Fyodorov IOL) to correct myopia 18 years previously. After a long lapse in the follow-up, the patient presented with a reduced endothelial cell count. Although the cataractogenic effect of first-generation PC pIOLs is well known, no sign of cataract was present. The patient was totally satisfied even after 18 years. To our knowledge, this is the first report of a long follow-up of a patient implanted with a first-generation PC pIOL.

[Iris-fixated intraocular lenses: reinforced monitoring]

In 1986, the concept of the claw lens was applied to correct myopia in phakic patients. Since then, progress has made iris-fixated phakic intraocular lenses (IOL) relatively safe, predictable, and effective for the correction of myopia, hyperopia, and astigmatism. All these models have undergone a series of design improvements to prevent complications. Despite having excellent refractive results, the principal risk is a potential progressive endothelial cell loss. Many authors have presented encouraging results. Phakic iris-fixated IOL surgery is a potentially reversible procedure, but the surgeon cannot rule out the possibility of complications. Therefore, long-term follow-up is mandatory.

[Pigment dispersion and Artisan implants: crystalline lens rise as a safety criterion]

PURPOSE

To validate the theoretical notion of a crystalline lens rise as a safety criterion for ARTISAN implants in order to prevent the development of pigment dispersion in the implanted eye.

MATERIAL AND METHOD

Crystalline lens rise is defined by the distance between the crystalline lens's anterior pole and the horizontal plane joining the opposite iridocorneal recesses. We analyzed the biometric measurements of 87 eyes with an Artisan implant. A comparative analysis of the crystalline lens rise was carried out on the nine eyes having developed pigment dispersion and 78 eyes with no problems. Among the modern anterior segment imaging devices (Artemis, Scheimpflug photography, optical coherence tomography, radiology exploration, magnetic resonance imaging, TDM), an anterior chamber optical coherence tomography (AC-OCT) prototype was used.

RESULTS

This working hypothesis was confirmed by this study: the crystalline lens rise must be considered as a new safety criterion for implanting Artisan phakic lenses. Indeed, the higher the crystalline lens's rise, the greater the risk of developing pigment dispersion in the pupil area. This complication is more frequent in hyperopes than in myopes. We can consider that there is little or no risk of pigment dispersion if the rise is below 600 microm; however, at 600 microm or greater, there is a 67% rate of pupillary pigment dispersion. In certain cases, when the implant was loosely fixed, there was no traction on the iris root. This is a complication that can be avoided or delayed.

CONCLUSIONS

The crystalline lens rise must be part of new safety criteria to be taken into consideration when inserting an Artisan implant. This notion must also be applied to other types of phakic implants. The distance remaining between the crystalline lens rise and a 600-micromm theoretical safety level allows one to calculate a safety time interval.

Pigment dispersion and Artisan phakic intraocular lenses

PURPOSE

To validate the theory that crystalline lens rise can be used as a safety criterion to prevent pigment dispersion in eyes with an Artisan phakic intraocular lens (IOL) (Ophtec BV).

SETTING

Monticelli Clinic, Marseilles, France.

METHOD

A comparative analysis of crystalline lens rise in 9 eyes with pigment dispersion and 78 eyes without dispersion was performed. All eyes had previous implantation of an Artisan IOL. Anterior segment imaging was done using an anterior chamber optical coherence tomography (AC OCT) prototype. Crystalline lens rise was defined by the distance between the anterior pole of the crystalline lens and the horizontal plane joining the opposite iridocorneal recesses.

RESULTS

The study confirmed that crystalline lens rise can be considered a safety criterion for implantation of Artisan-type phakic IOLs. The higher the crystalline lens rise, the greater the risk for developing pigment dispersion in the area of the pupil. This complication occurred more frequently in hyperopic eyes than in myopic eyes. Results indicate there is little or no risk for pigment dispersion if the rise is less than 600 microm; 67% of eyes with a rise of 600 microm or more developed pupillary pigment dispersion. In some cases in which the IOL was loosely fixated, there was no traction on the iris root and dispersion was prevented or delayed.

CONCLUSIONS

Crystalline lens rise should be considered a new safety criterion for Artisan phakic IOL implantation and should also be applied to other types of phakic IOLs. The distance remaining between the crystalline lens rise and a 600 microm theoretical safety level allows one to calculate how long the IOL can safely remain in the eye.