Implantation of an iris-fixated phakic intraocular lens for the correction of hyperopia: 15-year follow-up.

PURPOSE: To assess the predictability, efficacy, stability, and safety of implantation of an Artisan iris-fixated phakic intraocular lens (IF-pIOL) for the correction of hyperopia with a follow-up of up to 15 years. SETTING: Leiden University Medical Center, the Netherlands. METHODS: Patients operated by a single surgeon up to 2007 were identified, and data on refraction, corrected distance visual acuity (CDVA), uncorrected distance visual acuity, endothelial cell (EC) density, and complications were collected. RESULTS: A total of 61 eyes (32 patients) were analysed. The mean spherical equivalent decreased from +6.43 ± 1.78 diopters (D) preimplantation to -0.22 ± 0.57 D at 1 year postimplantation and remained stable throughout follow-up. A stable CDVA with safety indices ranging from 0.91 to 1.10 and efficacy indices between 0.43 and 0.86 were observed. Follow-up time had a significant effect on EC density with an estimated annual decline of 58 cells/mm2 after IF-pIOL implantation. IF-pIOL explantation was performed in a 10 eyes (16.4%) after 8.13 ± 5.11 years. The main reason for IF-pIOL explantation was EC loss (4 eyes [6.6%]). Pigment dispersion was the most encountered complication, observed in 9 eyes (14.8%). CONCLUSIONS: Visual and refractive results after implantation of an IF-pIOL to correct hyperopia show favorable and stable results with long-term follow-up. Lifelong monitoring of EC counts is mandatory. Pigment dispersion might be a problem in hyperopic eyes implanted with an IF-pIOL; a shallower anterior chamber depth and a convex iris configuration might be predisposing factors.

Long-term longitudinal changes in axial length in the Caucasian myopic and hyperopic population with a phakic intraocular lens.

PURPOSE: To determine the long-term longitudinal axial length changes in myopic and hyperopic adults with an iris-fixated phakic intraocular lens (pIOL). METHODS: The medical records of patients aged ≥18 years with myopia or hyperopia who were treated with pIOL implantation between 1996 and 2011 for refractive correction with a minimum follow-up of 5 years after pIOL implantation were analyzed. The main outcome measure was change in ocular axial length over time. RESULTS: 149 eyes of 149 myopic patients and 27 hyperopic eyes of 27 patients were included in this study. Mean patient age was 37.1 ± 10.4 years (35% male) in the myopic group and 39.4 ± 9.4 years (4% male) in the hyperopic group. The eyes of the myopic patients showed a significant mean increase in axial length of 0.45 ± 0.61 mm after a mean follow-up time of 144 ± 38 months (p < 0.001). In 26 eyes (17%), the axial length had increased by ≥1 mm. The mean annual axial length increase was 0.04 ± 0.06 mm. Axial elongation was associated with a higher degree of myopia (p < 0.001) and younger age (p = 0.02). The eyes of the hyperopic patients showed no change in axial length over time. CONCLUSIONS: Myopic eyes corrected with an iris-fixated pIOL show continuous increase in axial length at an adult age. Although this study is limited to subjects with a pIOL, this is the first time myopization in Caucasian adults has been reported in a large long-term longitudinal study.

Differences between Scheimpflug and optical coherence tomography in determining safety distances in eyes with an iris-fixating phakic intraocular lens.

PURPOSE: To investigate the agreement and reliability of anterior segment optical coherence tomography (AS-OCT) and Scheimpflug imaging in measuring the distance from the anterior edge of an iris-fixated phakic intraocular lens (IF-pIOL) to the corneal endothelium. METHODS: Anterior segment configuration was assessed in a total of 62 eyes of which 25 hyperopic and 37 myopic eyes, all corrected with an IF-pIOL. Measurements were performed by two independent observers using AS-OCT (Visante, Model 1000, Carl Zeiss Meditec Inc.) and Scheimpflug imaging (Pentacam HR, Oculus Optikgerate). The distance from the anterior edge of the pIOL to the endothelium was measured in five different positions using both modalities with their corresponding pIOL software. The measurements as well as the inter- and intra-observer reliability of the two imaging modalities were then compared. RESULTS: Distance measurements for all positions performed by AS-OCT were found to be significantly larger than those performed by Scheimpflug imaging, with mean differences ranging from 0.11 to 0.22 mm. Both instruments exhibited good inter- and intra-observer reliability. CONCLUSION: Anterior pIOL edge to endothelium distance measurements by AS-OCT and Scheimpflug imaging have good intra- and inter-observer reliability. However, as AS-OCT provides larger measurements, these two modalities cannot be used interchangeably. Correction of this difference might be essential for proper decision-making during pre-operative screening for pIOL implantation and post-operative safety monitoring.

Middle- and long-term results after iris-fixated phakic intraocular lens implantation in myopic and hyperopic patients: a meta-analysis.

The iris-fixated phakic intraocular lens (pIOL) has been available for over 25 years. To provide a clear picture of outcomes and risks, for this systematic review and meta-analysis, the literature was searched for reports on middle- and long-term effects. The iris-fixated phakic intraocular lens (pIOL) has been available for over 25 years. To provide a clear picture of outcomes and risks, for this systematic review and meta-analysis, the literature was searched for reports on middle- and long-term effects of iris-fixated pIOLs on myopic and hyperopic eyes with a follow-up of at least 2 to 4 years. Visual and refractive results after implantation for correction of myopia are positive and the complication rate is low. Endothelial cell loss appears to be at an acceptable rate, although the range of endothelial cell change is too wide to draw firm conclusions. Care should be taken when considering an iris-fixated pIOL for hyperopic eyes because complication rates, particularly pigment dispersion, might be higher than those in myopic eyes. More well-designed, long-term studies are needed, especially in hyperopic eyes. The authors advocate for standardized reporting of refractive surgery data. Initiatives proposed by journal authors and editors to achieve uniformity should be supported.

Straylight As The Result Of Refractive Correction.

PURPOSE: To investigate the effect of refractive correction on straylight. PATIENTS AND METHODS: Straylight values were measured with the C-Quant (Oculus Optikgeräte, GmbH, Wetzlar, Germany) in 1) near-emmetropic eyes (n=30) with various negative powered refractive lenses and in 2) myopic eyes (n=30) corrected with prescribed eyeglasses and contact lenses. The straylight measurements in each group were compared in the different conditions. RESULTS: In the near-emmetropic group, a significant effect (p<0.001) of each added negative diopter was found to increase straylight values with 0.006 log-units. In the second group, no significant correlation with type of correcting lens was found on straylight values. CONCLUSION: Refractive correction with high minus power (contact) lenses result in subtle increase of straylight values. These changes are relatively small and do not lead to visual disability in a clinical setting.

Correlations between ocular biometrics and refractive error: A systematic review and meta-analysis.

The understanding of correlations between different biometric parameters is essential for personalized eye care in the field of cataract and refractive surgery. This systematic review offers a clear overview of the previous literature assessing these correlations including a meta-analysis. The review is focused on the following five correlations: (1) axial length and refractive error; (2) anterior chamber depth and refractive error; (3) axial length and anterior chamber depth; (4) corneal power and refractive error; (5) corneal power and axial length. An expected strong correlation between axial length and refractive error was found. Correlations including corneal power were weak and might be clinically insignificant.