Phakic Refractive Lens Research Articles

Effect of posterior chamber phakic refractive lens implantation on the ocular surface and tear film

To evaluate changes in dry eye-related parameters after posterior chamber phakic refractive lens (PC-PRL) implantation. This prospective study included 21 highly myopic patients (39 eyes) who underwent PC-PRL implantation at Lanzhou Huaxia Eye Hospital between January 2021 and June 2022, with a 3-month postoperative follow-up. In addition to routine preoperative examinations, dry eye assessments were conducted preoperatively and at 1 week, 1 month, and 3 months postoperatively. These assessments included the Ocular Surface Disease Index (OSDI) questionnaire score, non-invasive first tear break-up time (NIF-BUT), non-invasive average tear break-up time (NIA-BUT), tear meniscus height (TMH), meibomian gland loss (MGL) rate, and Schirmer I test (SIt). Repeated measures ANOVA was used to compare the differences in parameters across different time points, with pairwise comparisons conducted using the LSD-t test. After grouping, the Student's t-test was applied to compare normally distributed data, while the Mann–Whitney U test was used for non-normally distributed data. Categorical data were analyzed using the chi-square test. A total of 21 patients (39 eyes) were included, comprising 10 males (19 eyes) and 11 females (20 eyes), aged 19 to 49 years (33.76 ± 7.87). All patients completed the 3-month follow-up. Significant differences in OSDI scores were observed pre- and post-surgery (P = 0.008), with a peak at one week post-surgery (P < 0.001), then stabilizing at one and three months post-surgery. Postoperative NIF-BUT and NIA-BUT significantly decreased (P < 0.001 for both) but returned to preoperative levels within three months. There were no significant changes in TMH, MGL, or SIt postoperatively (P > 0.05). Significant differences in dry eye parameters were observed between the dry eye and control groups before and after surgery (P < 0.001). PC-PRL implantation impacts tear film stability on the ocular surface after surgery, leading to varying degrees of dry eye symptoms in patients. After surgery, all dry eye parameters return to their preoperative levels within three months.

Numerical simulation of aqueous flow in a novel posterior chamber phakic intraocular lens versus its counterparts

Phakic intraocular lenses (pIOLs), particularly posterior chamber pIOLs, are becoming important for patients with high myopia and thin corneas. By phakic intraocular, we mean the ocular environmental conditions, where the natural lens is unremoved. A new posterior chamber pIOL, the sine wave phakic refractive lens (SW-PRL), is in the development stage, and its aqueous humor (AH) dynamics and the effects of intraocular geometry on the flow characteristics are not well understood. To analyze the adaptability and functionality of SW-PRL, a comparison study is made with its counterparts, the posterior chamber phakic refractive lens (PC-PRL), PC-PRL combined with peripheral iridotomy [PC-PRL(PI)], and implantable collamer lens with a central hole (ICL V4c). The result demonstrates that SW-PRL has a positive effect on AH flow circulation. Interestingly, there is a relationship between a posterior chamber flow and the type of pIOLs with vault variation. With an increase in vault, the flow between the lens and pIOLs slowed down after ICL V4C implantation but accelerated after PC-PRL (PI) implantation with little change after SW-PRL implantation. On the rear surface of the iris, the wall shear stress (WSS) was lower for PC-PRL(PI), SW-PRL, and ICL V4c (5.6 × 10−4, 6 × 10−3, and 8.2 × 10−3 Pa, respectively) compared to the PC-PRL (0.14 Pa), and on the front surface of lens, the WSS was lower for PC-PRL and SW-PRL (1.16 × 10−5 and 9.7 × 10−6 Pa, respectively) compared to the ICL V4c (8.2 × 10−4 Pa). WSS on the cornea surface was similar for each pIOL. These might provide a fresh viewpoint on the clinical decision of different intraocular lenses.

Clinical efficacy of posterior chamber phakic refractive lens implantation in the treatment of ultra-high myopia

Clinical efficacy of posterior chamber phakic refractive lens implantation in the treatment of ultra-high myopia

Assessment of biosafety and implantation feasibility of novel phakic refractive lens

PurposeWe investigated the biosafety and implantation feasibility of a new phakic refractive lens (PRL) in rabbit eyes.MethodsShort PRLs (S-PRLs), large PRLs (L-PRLs), and large-grooved PRLs (LG-PRLs), were prepared by molding medical-grade liquid silicon. The cytotoxicity and cellular adhesion of the PRLs was assessed in vitro. To assess implantation feasibility, the S-PRL, L-PRL, and LG-PRL were implanted in the posterior chamber of rabbit eyes and the relative position was assessed by optical coherence tomography. The intraocular pressures (IOP) were compared between the S-PRL, L-PRL, LG-PRL, and control groups to evaluate the PRL biosafety after implantation.ResultsThe in vitro assays showed that cell viability and cellular adhesion in the S-PRL, L-PRL and LG-PRL groups was not significantly different to those in the control group throughout the study. After implantation into the posterior chamber of rabbit eyes, there were no obvious signs of inflammation or increases in IOP at each time point relative to the control group, demonstrating good biosafety of the PRL. The relative positions of the L-PRLs and LG-PRLs in the posterior chamber were appropriate and the retention frequencies were high.ConclusionsThe newly developed LG-PRL showed good biosafety with negligible in vitro cytotoxicity, ocular inflammation, or fluctuations in IOP. The LG-PRL provided the best implantation feasibility. The grooves on the LG-PRL provided channels for aqueous humor circulation. The LG-PRL is a promising type of PRL with an appropriate size and surface structure for effective correction of refractive errors in rabbit eyes.

Safety and visual outcomes following posterior chamber phakic intraocular lens bilensectomy

BackgroundTo evaluate the safety, efficacy, refractive outcomes and causes for bilensectomy (phakic intraocular lens – pIOL – explantation with cataract surgery and pseudophakic intraocular lens implantation) in patients previously implanted with posterior chamber pIOLs.MethodsThis multi-center retrospective study included 87 eyes of 55 patients who underwent bilensectomy for posterior chamber pIOL with a follow up time of 12 months. The uncorrected and best corrected distance visual acuities (UDVA, CDVA), endothelial cell density before and after bilensectomy were assessed, as well as the cause of bilensectomy and intra or postoperative complications.ResultsThere was a statistically significant improvement in uncorrected and best corrected visual acuities after bilensectomy (p = 0.00). The main reason for bilensectomy was cataract development (93.1% of the cases), followed by miscalculation of lens size, and corneal edema. The endothelial cell count remained stable without a statistically significant change after surgery (p = 0.67). The refractive efficacy index was 0.8, none of the patients lost lines of CDVA after surgery, 73% of the patients were within ±1 D (spherical equivalent) of the target refraction. Intraoperative complications were one posterior capsule rupture with the intraocular lens (IOL) implanted in the sulcus, and 3 eyes required the use of pupil expanders for adequate pupil dilation. Postoperatively, one eye developed retinal detachment. The three pIOLs models explanted were the Implantable Collamer Lens (ICL), Implantable Phakic Contact Lens (IPCL) and the Phakic Refractive Lens (PRL).ConclusionsGood safety and visual outcomes were observed 1 year after bilensectomy for posterior chamber phakic intraocular lenses (PC pIOLs). There were few intra and postoperative complications and there was no significant endothelial cell loss after the bilensectomy procedure.

The Implantable Collamer Lens with a central port: review of the literature.

The purpose of this review is to summarize preclinical and clinical data from publications appearing in the peer-reviewed scientific literature relevant to the safety and effectiveness of the EVO Implantable Collamer Lens (ICL) posterior chamber phakic refractive lens with a central port (V4c Visian ICL with KS Aquaport, STAAR Surgical, Inc.). A literature search was conducted using PubMed.gov to identify all articles relating to the EVO ICL. Articles were examined for their relevance, and the references cited in each article were also searched for additional relevant publications. On the basis of a total of 67 preclinical studies and clinical reports, including effectiveness data on 1,905 eyes with average weighted follow-up of 12.5 months and safety data on 4,196 eyes with weighted average follow up of 14.0 months, the EVO ICL is safe and effective for the correction of a broad range of refractive errors. High levels of postoperative uncorrected visual acuity, refractive predictability, and stability demonstrate the effectiveness of the EVO ICL. Safety data suggest reduced rates of anterior subcapsular cataract and pupillary block compared with earlier models. Improved safety and proven effectiveness make EVO an attractive option for surgeons and patients.

Femtosecond laser–assisted cataract surgery in eyes with foldable anterior or posterior chamber phakic intraocular lenses

We describe a technique for the application of femtosecond laser-assisted cataract surgery in eyes with cataract and previous implantation of a foldable anterior or posterior chamber phakic intraocular lens (pIOL). In 2 eyes with an anterior chamber pIOL (angle-supported Acrysof Cachet) and 3 eyes with a posterior chamber pIOL (2 eyes with an Implantable Collamer Lens pIOL; 1 eye with a Phakic Refractive Lens), a femtosecond laser was used to create a capsulotomy, perform lens fragmentation, and create corneal incisions with the pIOL insitu. In all cases, the capsulotomy was created successfully. Lens fragmentation was complete in 4 eyes and incomplete in 1 eye, where trapped cavitationbubbles in the space between the posterior chamber pIOL and anterior lens capsule were evident as a result of a shallow vault of the pIOL.

English

Abstract This article presents two cases of phakic refractive lens (PRL) complications in China. Case 1 presents a highly myopic patient with PRL's footplate partly subluxated into the anterior chamber by blunt trauma one year after implantation. The PRL was repositioned successfully without other complications. Case 2 represents a case of pigment dispersion glaucoma developed seven years after PRL implantation. Intraocular pressure (IOP) lowering therapy was initiated and the IOP continued to be in the normal range for both affected eyes with ongoing follow-up. The preciseness in sulcus-to-sulcus measurements is important to minimize the risk of dislocation and crystalline lens touch; thus, a careful preoperative evaluation should be performed to exclude the presence of glaucoma, and the patients undergoing the procedure need to be informed about the increased risk for glaucoma. In summary, a comprehensive ophthalmic evaluation is essential to optimize both patient and PRL selection to minimize the risk for potential complications, and the PRL implantation warrants long-term follow-up.

Intraocular Optical Quality of Phakic Intraocular Lenses: Comparison of Angle-Supported, Iris-Fixated, and Posterior Chamber Lenses

To evaluate internal aberrometric profiles following phakic intraocular lens (PIOL) implantation. Retrospective and consecutive case series. One hundred and five eyes of 65 patients were included. The optical aberrations were measured with the Topcon KR-1W aberrometer. Comparisons of internal aberrations for different models were made. Comparisons at 4 and 6 mm were made also within the same model for all the lenses. Comparisons regarding the implantation site were also performed: angle-supported (AS) anterior chamber (AC) (n = 47), iris-fixated (IF) (n = 27), and posterior chamber (PC) (n = 31). Root mean square (RMS) of internal optical higher-order aberrations (HOAs) changed significantly to higher values from 4-6 mm aperture diameter in each PIOL, as should be expected. However, this significant change was not detected in spherical aberration for Kelman Duet (P = .753) and in trefoil for Acrysoft (P = .059). Kelman lens showed significantly lower values of spherical aberration compared to Acrysoft at 4 mm (P = .022) and at 6 mm (P = .042). Acrysoft showed the lowest values at central zone for trefoil (P = .043) and tetrafoil (P = .002) in AC group. In the IF group, Artisan and Artiflex showed similar results for all internal aberrations. In the comparison between Visian Implantable Collamer Lens (ICL; STAAR Surgical Co, Monrovia, California, USA) and phakic refractive lens (PRL), both for posterior chamber, significantly lower values of coma were observed for ICL (P = .033). IF lenses showed clinical evidence, but not significant, of better centering capability than AS lenses (P = .096). The study of intraocular aberrations is an adequate method to identify the clinical optical behavior and could help the surgeon to identify the most frequent problems related with each model.

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.

Preliminary in vivo positional analysis of a posterior chamber phakic intraocular lens by optical coherence tomography and its correlation with clinical outcomes

PurposeTo analyze by spectral-domain optical coherence tomography the anatomical relationship of a specific type of posterior chamber phakic intraocular lens (pIOL) implanted in cases of high to moderate myopia with the adjacent intraocular structures and to correlate it with clinical outcomes. MethodsProspective observational case series including 18 eyes with high to moderate myopia (spherical equivalent between −5.88 and −15.75D) of 9 patients (age range, 29–49 years) undergoing bilateral Phakic Refractive Lens (PRL, Zeiss) implantation. Postoperative visual acuity, refraction, contrast sensitivity (CS), and ocular higher order aberrations (HOA) were evaluated. Furthermore, the in vivo position of the PRL was analyzed by means of spectral domain optical coherence tomography (3D OCT-1000, Topcon). Central (CENV), temporal (TEMV) and nasal vault (NASV) were measured. Correlation of these anatomical parameters with clinical data was also investigated. Mean follow-up was 47±25 months. ResultsA statistically significant visual and refractive improvement (p<0.01) was found postoperatively. Mean postoperative CENV, NASV, and TEMV were 157.88±69.93μm, 168.29±65.02μm, and 188.59±55.99μm, respectively. Significant difference was found between NASV and TEMV (p=0.01). No significant correlations were found between ocular aberrometric and anatomical parameters (p≥0.12). CENV, NASV and TEMV correlated significantly with 6-cycles per degree (cpd) photopic CS as well as with 18-cpd low mesopic CS (r≥0.57, p≤0.04). Furthermore, NASV also correlated significantly with preoperative anterior chamber depth (r=−0.65, p=0.01). ConclusionsThis posterior chamber pIOL shows a trend to nasal position, with potential impact on refractive and visual outcomes, particularly in eyes with deep anterior chambers.

Visual and optical performance and quality of life after implantation of posterior chamber phakic intraocular lens

To evaluate visual, optical, and quality of life (QoL) outcomes and intercorrelations after bilateral implantation of posterior chamber phakic intraocular lenses. Twenty eyes with high to moderate myopia of 10 patients that underwent PRL implantation (Phakic Refractive Lens, Carl Zeiss Meditec AG) were examined. Refraction, visual acuity, photopic and low mesopic contrast sensitivity (CS) with and without glare, ocular aberrations, as well as QoL outcomes (National Eye Institute Refractive Error Quality of Life Instrument-42, NEI RQL-42) were evaluated at 12 months postoperatively. Significant improvement in uncorrected (UDVA) and best-corrected distance (CDVA) visual acuities were found postoperatively (p < 0.01), with significant reduction in spherical equivalent (p < 0.01). Low mesopic CS without glare was significantly better than measurements with glare for 1.5, 3, and 6 cycles/degree (p < 0.01). No significant correlations between higher order root mean square (RMS) with CDVA (r = -0.26, p = 0.27) and CS (r ≤ 0.45, p ≥ 0.05) were found. Postoperative binocular photopic CS for 12 cycles/degree and 18 cycles/degree correlated significantly with several RQL-42 scales. Glare index correlated significantly with CS measures and scotopic pupil size (r = -0.551, p = 0.04), but not with higher order RMS (r = -0.02, p = 0.94). Postoperative higher order RMS, postoperative primary coma and postoperative spherical aberration was significant higher for 5-mm pupil diameter (p < 0.01) compared with controls. Correction of moderate to high myopia by means of PRL implantation had a positive impact on CS and QoL. The aberrometric increase induced by the surgery does not seem to limit CS and QoL. However, perception of glare is still a relevant disturbance in some cases possibly related to the limitation of the optical zone of the PRL.

Clinical Impact of a Spontaneous Decentration of a Phakic Refractive Lens

To evaluate the clinical impact and possible causes of a spontaneous decentration of a phakic refractive lens (PRL) implanted in a highly myopic eye, and analyzing the visual, refractive, and aberrometric outcome as well as the possible causes for this phenomenon. The description of a case of bilateral high myopia corrected by implantation with the phakic intraocular lens (pIOL) PRL (Carl Zeiss Meditec, Germany) is presented and documented. Both eyes had similar anatomical configuration, and therefore, a pIOL (Model 101) with the same size was implanted without any associated intraoperative complication. Clinical outcomes were evaluated during a 3-month follow-up. Implanted pIOLs were properly positioned in both eyes and provided an excellent visual outcome during the immediate postoperative period. However, 1 month after surgery, the patient presented a logarithm of the minimum angle of resolution uncorrected distance visual acuity of 0.15 and 0 in the OD and OS, respectively. Subjective refraction in the OD was +1.00 to 1.00 × 15°, with logarithm of the minimum angle of resolution corrected distance visual acuity of 0. Temporal displacement of the PRL was evident in the biomicroscopic examination and analyzed in detail with advanced imaging techniques finding an asymmetric vault. Regarding aberrometry, larger amounts of primary coma, and spherical aberration were present in the OS. Two months later, the situation remained stable. Spontaneous PRL decentration is not necessarily associated with a visual quality loss and a bad selection of pIOL size. For implantation of this pIOL, a comprehensive analysis of the zonule would be necessary.

Long-term Results of Phakic Refractive Lens Implantation in Eyes With High Myopia

To evaluate the long-term results of phakic refractive lens (PRL; Carl Zeiss Meditec) implantation in eyes with high myopia. In this retrospective, noncomparative, interventional case series, 143 myopic eyes of 82 patients were treated for high myopia with the implantation of the silicone PRL in the posterior chamber. Mean follow-up was 3.8±1.7 years (range: 1 to 6 years). Six years postoperatively (n=34), a statistically significant reduction was noted in the cycloplegic spherical equivalent from -14.08±4.00 diopters (D) (range: -24.88 to -4.75 D) before PRL implantation to -0.45±0.62 D (range: -1.00 to 1.00 D) (P<.001). At 6 years, 67.6% (23 eyes) and 91.2% (31 eyes) were within ±0.50 and ±1.00 D of target refraction, respectively. Mean logMAR uncorrected and corrected distance visual acuity improved significantly (P<.001) (counting fingers preoperatively in all eyes to 0.17±0.15 [range: 0.54 to -0.06] and 0.19±0.19 [1.00 to -0.08] to 0.07±0.10 [range: 0.30 to -0.10], respectively). Complications included anterior capsule damage (3 eyes), temporary intraocular pressure increase (14 eyes), pigment dispersion (1 eye), and PRL decentration (1 eye). No eyes presented any signs of cataract up to 6 years postoperatively. Long-term results show that PRL implantation is an effective and safe method for treating high myopia.

Phakic Refractive Lens: Two-year Results

To evaluate the surgical outcome and adverse events associated with correction of myopia and hyperopia with a phakic refractive lens (PRL), and to determine the random errors of the analytical methods used in the trial. In this prospective clinical study, 14 myopic and 6 hyperopic PRLs were implanted in 20 eyes of 20 patients from April to November 2002. Follow-up included evaluation of the PRL rotation with retroillumination photography, the distance between the PRL and crystalline lens with Scheimpflug images, laser flare meter, endothelial cell count, uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA), refraction, intraocular pressure, and induced cataract. The random errors of the measurements with laser flare meter were 17%, with Scheimpflug images 10%, and with endothelial cell count 2.8%. Postoperatively, 25% of eyes gained 2 or more lines and no eye lost 2 or more lines of BSCVA. Mean UCVA was 0.89 +/- 0.34. Laser flare values returned to baseline at 3 months and had no changes at 1 or 2 years (P > .05). The PRL rotated less during the second year than the first year. The distance between the PRL and crystalline lens was less at 1 year than at baseline (P < .05) but had no change during the second year. No statistically significant endothelial cell loss was noted between 1 week and 1 or 2 years postoperatively (P > .05). Two (10%) eyes developed pupillary block, one (5%) hyperopic eye showed unexpected postoperative myopia, and in another hyperopic eye (5%) the horizontal iris transillumination defects were noticed at 1 year combined with slight pupil ovalization at 2 years. No induced cataract, glaucoma, or inflammation was observed. Safety and efficacy indexes were high at 2-year follow-up. The distance between the PRL and crystalline lens decreased by 59% during the first year but seemed to stabilize thereafter. The PRL rotated in only a few eyes after the first year.

The stress on the anterior lens surface during human in vivo accommodation

Purpose:To determine the qualitative change in stress on the lens capsule during in vivo human accommodation.Methods:Nine subjects (mean age: 30 years; range: 25–38 years) were studied, each of whom had...

Phakic Refractive Lens (Medennium) for Correction of +4.00 to +6.00 Diopters: 1-year Follow-Up

To study the efficacy and safety of phakic refractive lens (PRL) implantation to correct high hyperopia. Inclusion criteria for this prospective, observer-masked, interventional study were spherical equivalent > or =+4.00 diopters (D) of cycloplegic hyperopia, best spectacle-corrected visual acuity (BSCVA) > or =0.5, anterior chamber depth > or =3 mm, and mesopic pupil size < or =6 mm. Lenses were implanted in all cases under regional anesthesia using forceps. Sixteen eyes of nine patients were included in the study. Mean preoperative spherical equivalent refraction was +5.65+/-1.41 D (range: +3.25 to +5.75 D). Mean 1-year postoperative spherical equivalent refraction was +0.07+/-0.43 D (range: -0.50 to 0.75 D). Fifteen (93.75%) eyes were within +/-0.50 D of emmetropia, and 16 (100%) eyes were within +/-1.00 D of emmetropia. Safety and efficacy indexes were 0.9 and 0.8, respectively. Eight (50%) eyes needed LASIK to correct residual astigmatism. Five (31.25%) eyes lost one line of BSCVA; no eye lost two or more lines of BSCVA. The BSCVA did not increase in any eye. No significant intraocular complications developed. Phakic refractive lens implantation to correct high hyperopia seems to be a safe and accurate procedure. A mild but significant loss in BSCVA can be anticipated.

Accommodation‐ presbyopia: mechanism etiology

The purpose of the presentation is to elucidate the mechanism of accommodation and etiology of the age‐related decline in accommodative amplitude that results in presbyopia in the fifth decade of life. Multiple physical, mathematical, clinical, in vitro, and in vivo experiments demonstrate that the human crystalline lens develops an unusual shape during accommodation. Central lens thickness increases; the curvatures of the central surfaces of the lens steepen; while the peripheral surfaces of the lens flatten. This ‘steep profile’ also occurs in other biconvex objects that have an aspect ratio ≤ 0.6 (minor axis to major axis ratio) in response to a small equatorial displacement when the volume of the object only minimally changes. The ‘steep profile’ even occurs when the major axis of an ellipse with an aspect ratio ≤ 0.6 is increased and the area enclosed by the ellipse is held constant or permitted to decrease by 2%. The universality of the occurrence of a ‘steep profile’ implies that the lens is under increased tension during accommodation. This hypothesis was confirmed by using high‐resolution anterior segment optical coherence tomography (OCT) to measure the change of stress on the anterior lens capsule in patients who had undergone a phakic refractive intraocular lens (PRL) at least 1 year prior to the study. The PRL served as an internal control. It was found that during a mean of 8‐diopters of in vivo accommodation, the stress on the lens was increased during accommodation, p &lt; 0.001. The increased stress on the lens capsule during accommodation occurs as a consequence of increased equatorial zonular tension. Normal equatorial lens growth predicts both the age‐related decline in accommodative amplitude and the age‐related increase in intraocular pressure (IOP). The rapid decline in accommodative amplitude and rapid increase in IOP that occur during childhood and their slower changes thereafter, both match the logarithmic pattern of equatorial lens growth, R2 = 0.90. In summary, the lens is under increased stress during accommodation as a consequence of increased equatorial zonular tension. Normal equatorial lens growth is the etiology of both the age‐related decline in accommodative amplitude that results in presbyopia in the fifth decade of life and the increase in IOP that occurs with age.

Comparison of Contrast Sensitivity after Angle-Supported, Iris-Fixated and Posterior Chamber Phakic Intraocular Lens Implantation for High Myopia

Purpose: To evaluate the effects of angle-supported, iris-fixated and posterior chamber phakic intraocular lens (PIOL) implantation on contrast sensitivity (CS). Methods: This prospective study included 69 eyes of 41 consecutive cases of high myopia which received an angle-supported (Phakic-6H; 26 eyes), iris-fixated (Verisyse; 23 eyes) or posterior chamber PIOL [phakic refractive lens (PRL); 20 eyes]. Photopic, mesopic and mesopic with glare CS were evaluated preoperatively and at least 6 months postoperatively. Results: In the PRL group, the mean postoperative CS at all frequencies and across all lighting conditions increased. These changes were significant for 6, 12 and 18 cycles per degree (cpd) under both photopic and mesopic conditions (p < 0.01) and for all the tested frequencies under mesopic with glare condition (p < or = 0.01). The average CS was relatively low in the PRL group. These changes were significant for 6 and 12 cpd between the Verisyse and PRL group under photopic condition (p < 0.05), for 3 and 6 cpd under mesopic condition (p < 0.01, p = 0.01) and under mesopic with glare condition (p < 0.01, p < 0.05). Conclusions: Improvements in postoperative CS confirm that PIOL implantation is a promising alternative for correction of high myopia. In comparison to posterior chamber PIOLs, angle-supported and iris-fixated PIOLs seem to produce a better visual quality in terms of CS, which needs to be warranted by further investigations.

Medennium Posterior Chamber Phakic Refractive Lens to Correct High Myopia

To determine the efficacy and safety of phakic refractive lens implantation to correct high myopia. In this prospective study, a phakic refractive lens was implanted in 90 myopic eyes in which refractive errors ranged from -6.00 to -20.00 diopters (D) and laser refractive surgery was contraindicated. Uncorrected visual acuity (UCVA) and best-spectacle corrected visual acuity (BSCVA), manifest and cycloplegic refractions, and intraocular pressure (IOP) were assessed during a 1-year follow-up period. Possible complications, including endothelial cell counts, were evaluated. Spherical equivalent refraction measurements revealed a significant change from the preoperative mean value of -11.90+/-5.00 D to 0.04+/-0.20 D 1 year postoperatively (P=.001). The UCVA and BSCVA significantly improved postoperatively (P=.001 and P=.01, respectively). Seventy-two (80%) eyes and 61 (68%) eyes were within +/-1.00 D and +/-0.50 D of the target refraction, respectively. A significant increase in IOP was found at every postoperative visit (P=.01). There was a trend toward decreased endothelial cell density postoperatively, although the difference did not reach significance. No major complications were found during the 1-year follow-up period. The implantation of a phakic refractive lens seems to be a predictable and well-tolerated procedure for correcting high myopia. Complications such as development of cataract, implant dislocation, decreases in endothelial cell counts, or development of glaucoma did not occur in this study.