Five-year Change in Corneal Endothelial Cell Density after Foldable Iris-fixed Lens Insertion

Purpose@#To investigate changes in corneal endothelial cell density over 5 years after implantation of Artiflex lenses (Ophtec BV, Groningen, The Netherlands) and to explore the influence of anterior chamber depth and volume on changes in endothelial cell density. @*Methods@#This study included 146 eyes of 88 patients implanted with foldable phakic iris-fixation intraocular (Artiflex) lenses for myopia correction from March 2009 to March 2014. To simulate chronological changes in endothelial cell density with age, we collected normal endothelial cell density data from 100 healthy subjects aged 20, 25, or 30 years, and compared the changes among these groups at 5 years after surgery. Changes in corneal endothelial cell density were compared among four groups to which subjects were assigned based on the distance from the intraocular lens to the corneal endothelium, and the volume and depth of the preoperative anterior chamber. @*Results@#The mean endothelial cell density, pre-operatively and at 1, 3, and 5 years post-operatively, was 3,038.8 ± 223.2, 2,985.3 ± 235.5, 2,905.1 ± 231.3, and 2,814.9 ± 250.5 cells/mm2, respectively (1.73%, 4.36%, and 7.31% reduction, respectively, vs. pre-operatively, p < 0.001). These differences were greater than those observed among different age groups (2.2% difference between 20- and 25-year-olds, and 1.2% difference between 25- and 30-year-olds, p < 0.001). A shorter distance from the lens to the endothelium and smaller anterior chamber volume were associated with greater decreases in endothelial cell density following surgery. @*Conclusions@#Corneal endothelial cell density significantly decreased during a 5-year follow-up after Artiflex lens implantation. The distance from the intraocular lens to the corneal endothelium, and the anterior chamber volume, were negatively correlated with the rate at which endothelial cell density decreased over time.

Five-year Change in Corneal Endothelial Cell Density after Foldable Iris-fixed Lens Insertion

Purpose@#To investigate changes in corneal endothelial cell density over 5 years after implantation of Artiflex lenses (Ophtec BV, Groningen, The Netherlands) and to explore the influence of anterior chamber depth and volume on changes in endothelial cell density. @*Methods@#This study included 146 eyes of 88 patients implanted with foldable phakic iris-fixation intraocular (Artiflex) lenses for myopia correction from March 2009 to March 2014. To simulate chronological changes in endothelial cell density with age, we collected normal endothelial cell density data from 100 healthy subjects aged 20, 25, or 30 years, and compared the changes among these groups at 5 years after surgery. Changes in corneal endothelial cell density were compared among four groups to which subjects were assigned based on the distance from the intraocular lens to the corneal endothelium, and the volume and depth of the preoperative anterior chamber. @*Results@#The mean endothelial cell density, pre-operatively and at 1, 3, and 5 years post-operatively, was 3,038.8 ± 223.2, 2,985.3 ± 235.5, 2,905.1 ± 231.3, and 2,814.9 ± 250.5 cells/mm2, respectively (1.73%, 4.36%, and 7.31% reduction, respectively, vs. pre-operatively, p < 0.001). These differences were greater than those observed among different age groups (2.2% difference between 20- and 25-year-olds, and 1.2% difference between 25- and 30-year-olds, p < 0.001). A shorter distance from the lens to the endothelium and smaller anterior chamber volume were associated with greater decreases in endothelial cell density following surgery. @*Conclusions@#Corneal endothelial cell density significantly decreased during a 5-year follow-up after Artiflex lens implantation. The distance from the intraocular lens to the corneal endothelium, and the anterior chamber volume, were negatively correlated with the rate at which endothelial cell density decreased over time.

Biomechanical Properties of the Cornea Using a Dynamic Scheimpflug Analyzer in Healthy Eyes

PURPOSE: To investigate biomechanical properties of the cornea using a dynamic Scheimpflug analyzer according to age. MATERIALS AND METHODS: In this prospective, cross-sectional, observational study, participants underwent ophthalmic investigations including corneal biomechanical properties, keratometric values, intraocular pressure (IOP), and manifest refraction spherical equivalent (MRSE). We determined the relationship of biomechanical parameters and ocular/systemic variables (participant's age, MRSE, IOP, and mean keratometric values) by piecewise regression analysis, association of biomechanical parameters with variables by Spearman's correlation and stepwise multiple regression analyses, and reference intervals (RI) by the bootstrap method. RESULTS: This study included 217 eyes of 118 participants (20–81 years of age). Piecewise regression analysis between Corvis-central corneal thickness (CCT) and participant's age revealed that the optimal cut-off value of age was 45 years. No clear breakpoints were detected between the corneal biomechanical parameters and MRSE, IOP, and mean keratometric values. Corneal velocity, deformation amplitude, radius, maximal concave power, Corvis-CCT, and Corvis-IOP exhibited correlations with IOP, regardless of age (all ages, 20–44 years, and over 44 years). With smaller deformation amplitude and corneal velocity as well as increased Corvis-IOP and Corvis-CCT, IOP became significantly increased. We provided the results of determination of confidence interval from RI data using bootstrap method in three separate age groups (all ages, 20–44 years, and over 44 years). CONCLUSION: We demonstrated multiple corneal biomechanical parameters according to age, and reported that the corneal biomechanical parameters are influenced by IOP.

Comparison of Toric Foldable Iris-Fixated Phakic Intraocular Lens Implantation and Limbal Relaxing Incisions for Moderate-to-High Myopic Astigmatism

PURPOSE: To compare the effectiveness of toric foldable iris-fixated phakic intraocular lens (pIOL) implantation and non-toric foldable iris-fixated pIOL implantation with limbal relaxing incisions (LRIs) for correcting moderate-to-high astigmatism in myopic eyes. MATERIALS AND METHODS: The medical records of 146 patients (195 eyes) with myopic astigmatism who underwent toric foldable iris-fixated pIOL implantation (toric group; 94 eyes) or non-toric foldable iris-fixated pIOL implantation with concurrent LRIs (LRI group; 101 eyes) were retrospectively reviewed. For subgroup analysis, the two groups were subdivided according to preoperative astigmatic severity [moderate, 2.00 to <3.00 diopters (D); high, 3.00–4.00 D]. Visual and astigmatic outcomes were compared 6 months postoperatively. RESULTS: The uncorrected distance visual acuity was at least 20/25 in 100% and 98% of the toric and LRI group eyes, respectively. The toric group had lower mean residual cylindrical error (-0.67±0.39 D vs. -1.14±0.56 D; p<0.001) and greater mean cylindrical error change (2.17±0.56 D vs. 1.63±0.72 D; p<0.001) than the LRI group, regardless of the preoperative astigmatic severity. The mean correction index (1.10±0.16 vs. 0.72±0.24; p<0.001) and success index (0.24±0.14 vs. 0.42±0.21; p<0.001) also differed significantly between the groups. CONCLUSION: Both surgical techniques considerably reduced astigmatism and had comparable visual outcomes. However, toric foldable iris-fixated pIOL implantation was more reliable for correcting moderate-to-high astigmatism in myopic eyes.

Comparison of Toric Foldable Iris-Fixated Phakic Intraocular Lens Implantation and Limbal Relaxing Incisions for Moderate-to-High Myopic Astigmatism

PURPOSE: To compare the effectiveness of toric foldable iris-fixated phakic intraocular lens (pIOL) implantation and non-toric foldable iris-fixated pIOL implantation with limbal relaxing incisions (LRIs) for correcting moderate-to-high astigmatism in myopic eyes. MATERIALS AND METHODS: The medical records of 146 patients (195 eyes) with myopic astigmatism who underwent toric foldable iris-fixated pIOL implantation (toric group; 94 eyes) or non-toric foldable iris-fixated pIOL implantation with concurrent LRIs (LRI group; 101 eyes) were retrospectively reviewed. For subgroup analysis, the two groups were subdivided according to preoperative astigmatic severity [moderate, 2.00 to <3.00 diopters (D); high, 3.00–4.00 D]. Visual and astigmatic outcomes were compared 6 months postoperatively. RESULTS: The uncorrected distance visual acuity was at least 20/25 in 100% and 98% of the toric and LRI group eyes, respectively. The toric group had lower mean residual cylindrical error (-0.67±0.39 D vs. -1.14±0.56 D; p<0.001) and greater mean cylindrical error change (2.17±0.56 D vs. 1.63±0.72 D; p<0.001) than the LRI group, regardless of the preoperative astigmatic severity. The mean correction index (1.10±0.16 vs. 0.72±0.24; p<0.001) and success index (0.24±0.14 vs. 0.42±0.21; p<0.001) also differed significantly between the groups. CONCLUSION: Both surgical techniques considerably reduced astigmatism and had comparable visual outcomes. However, toric foldable iris-fixated pIOL implantation was more reliable for correcting moderate-to-high astigmatism in myopic eyes.