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

A posterior chamber phakic refractive lens dislocated into the vitreous

SIGNIFICANCE

We present a unique cause for zonular dehiscence, which provides a pathway for subsequent dislocation of an implanted phakic refractive lens (PRL) into the vitreous cavity.

PURPOSE

To determine the cause of zonular dehiscence and to avoid similar complications after PRL implantation in the future.

CASE REPORT

A 37-year-old highly myopic patient with refraction of -24.0 DS in both eyes received PRL implantation in both eyes. In the 14-month postoperative follow-up, it was found that the PRL dislocated into the vitreous cavity. The patient then underwent phacoemulsification and vitrectomy. The patient was treated successfully. No ocular complication was found. The visual acuity of the left eye was 20/40, two weeks after surgery.

CONCLUSIONS

We report a unique cause for zonular dehiscence, and the clarification of its detailed characteristics may contribute to prevention of such a complication in the future.

Intraocular Implantable Collamer Lens with a Central Hole Implantation: Safety, Efficacy, and Patient Outcomes

This review summarizes the available literature and provides updates on the efficacy, safety, and patient outcomes of phakic intraocular lens implantation using implantable collamer lens (ICL), with a focus on newer models with a central port (EVO/EVO+ Visian Implantable Collamer Lens, STAAR Surgical Inc.). All studies included in this review were identified from the PubMed database and were reviewed for relevancy of their topic. Data on hole-ICL implantation performed between October 2018 and October 2022 in 3399 eyes showed a weighted average efficacy index of 1.03 and a weighted average safety index of 1.19 within an average follow-up of 24.7 months. The incidence of complications such as elevated intraocular pressure, cataract, and corneal endothelial cell loss was low. Moreover, both quality of vision and quality of life improved after ICL implantation, confirming the benefits of this procedure. In conclusion, ICL implantation is a promising refractive surgery alternative to laser vision correction with excellent efficacy, safety, and patient outcomes.

Assessment of biosafety and implantation feasibility of novel phakic refractive lens

Purpose

We investigated the biosafety and implantation feasibility of a new phakic refractive lens (PRL) in rabbit eyes.

Methods

Short 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.

Results

The 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.

Conclusions

The 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.

Five Years Follow-Up of Acrysof Cachet® Angle-Supported Phakic Intraocular Lens Implantation for Myopia Correction

Purpose

The Acrysof Cachet® angle-supported phakic intraocular lens (pIOL) (Alcon Laboratories, Inc., Fort Worth, TX) is designed to correct high refractive errors in human eyes. The aim of this study was to evaluate the outcome of AcrySof Cachet® angle-supported pIOL implantation with particular regard to efficacy and safety of the implant over a 60-month follow-up period.

Design

Retrospective consecutive clinical case study.

Methods

Prior to pIOL implantation, patients had a complete ophthalmologic examination including objective and subjective refraction, uncorrected visual acuity (UCVA) and corrected distance visual acuity (CDVA), endothelial cells density (ECD), slit lamp photography, optical coherence tomography (OCT), Scheimpflug digital videokeratoscopy, optical biometry, slit lamp examination, intraocular pressure (IOP) measurement, and pupillometry. Postoperatively, patients received yearly a complete eye examination.

Results

Thirty-one eyes of 16 patients were included in this study. The mean age was 36.2 ± 8.1 years. UCVA (logMAR) improved from 1.33 ± 0.20 before surgery to 0.08 ± 0.14 one year after surgery and was 0.20 ± 0.20 five years after surgery. CDVA (logMAR) improved from 0.10 ± 0.10 before surgery to 0.05 ± 0.13 one year after surgery and was 0.04 ± 0.14 five years postoperatively. The mean percentage of endothelial cells loss (ECL) was 11.51% over the first year and 15.95% five years after surgery. There were no intraoperative complications in any of the eyes.

Conclusions

Our results up to five years after implantation of the AcrySof Cachet® angle-supported pIOL demonstrated very good outcomes in all above shown measurements, including CDVA, UCVA, and ECD. However, since major endothelial cell loss may occur in some patients with this type of pIOL, regular follow-up visits are required.

Evaluation of the anterior chamber angle by anterior segment optical coherence tomography after implantable phakic contact lens implantation in myopic eyes

PURPOSE

To evaluate the changes in the angle of the AC and lens vault after IPCL implantation by AS-OCT in myopic patients.

METHODS

This was a prospective observational study involving 30 myopic eyes implanted with IPCL. AS-OCT was used to evaluate lens vault and AC angle parameters including anterior chamber angle, angle opening distance and trabecular-iris space area (TISA) at 1, 3 and 6 months postoperatively.

RESULTS

All 3 AC angle parameters were significantly reduced at the 1st postoperative month compared to preoperative values, but remained stable thereafter with no significant change at the 3rd or 6th postoperative months. The lens vault showed no significant change over the entire follow-up period.

CONCLUSION

IPCL implantation is a safe method for correction of myopia with stable AC angle narrowing over the course of 6 months postoperatively as monitored using AS-OCT.

[Correction of ametropia with posterior chamber phakic intraocular lens]

Posterior chamber phakic intraocular lens (PIOL) implantation is a widely accepted and performed refractive surgery for correction of moderate and high myopia used when corneal laser ablation procedures are not suitable. This paper analyzes literature data to reveal the advantages and limitations of the technology.

Case Report: Dislocation Into Vitreous Cavity and Removal of a Posterior Chamber Phakic Intraocular Lens

Purpose:

To report a rare case of delayed dislocation of a novel posterior chamber phakic intraocular lens into the vitreous cavity, which was successfully treated by a reformed technique.

Case Presentation

A 29-year-old female received Ejinn phakic refractory lens (EPRL) implantation to correct her high myopia. Spontaneous dislocation into the vitreous cavity occurred 26-months post-operatively without traumatic history. Pars plana vitrectomy combined with cutting the EPRL into two equal pieces was performed to remove the dislocated EPRL.

Conclusion

Dislocation into the vitreous cavity of EPRL can be successfully and easily removed by our reformed technique. Concerns about zonules-related complications pre-operatively, intraoperatively, and post-operatively must be raised in the practice of EPRL implantation.

Comparison of visual outcomes after non-toric and toric implantable collamer lens V4c for myopia and astigmatism

PURPOSE

To evaluate the visual quality of myopic patients after non-toric versus toric implantable collamer lens (ICL and TICL, respectively) V4c, and to investigate the potential risk factors of postoperative night vision disturbances.

METHODS

This prospective cohort study included 42 eyes of 21 patients treated with ICL and 46 eyes of 23 patients treated with TICL. Refractive parameters and ocular aberrations were examined before and 6 months after surgery. Subjective quality of vision was scored by a validated questionnaire.

RESULTS

The efficacy index at 6 months was 1.14 ± 0.20 for ICL and 1.17 ± 0.16 for TICL; the safety index was 1.20 ± 0.17 for ICL and 1.20 ± 0.19 for TICL. The root mean square of total higher-order aberrations (HOAs) and trefoil was significantly increased, and no statistical differences between groups were detected in HOA changes. Many patients reported haloes (85.7% for ICL and 100% for TICL) and glare (76.2% for ICL and 65.2% for TICL), but most (94.4% for ICL and 95.5% for TICL) were satisfied or very satisfied with visual outcomes. Implantable collamer lens (ICL) toricity was the risk factor for frequency (OR = 2.81, p = 0.01), severity (OR = 3.85, p = 0.003) and bothering effect (OR = 2.89, p = 0.01) of haloes.

CONCLUSIONS

Implantable collamer lens and TICL provided comparable efficacy, safety and predictability, induced acceptable level of HOAs and achieved high satisfaction in correcting myopia and myopic astigmatism. Although not severe, haloes and glare have a non-negligible prevalence and ICL toricity is a potential risk factor of haloes.

Diode laser transscleral cyclophotocoagulation causes intraocular collamer lens displacement in pseudophakic eye: a case report

Background

With the rapid development of intraocular collamer lens (ICL) operation, it is foreseeable that we will encounter a large number of glaucoma patients with ICL implantation history. However, our current understanding of the treatment of glaucoma patients with ICL is limited. Hence we report a rare case of refractory glaucoma after intraocular collamer lens and intraocular lens implantation in a patient who underwent unsuccessful transscleral cyclophotocoagulation, which led to intraocular collamer lens displacement, angle closure and uncontrolled intraocular pressure.

Case presentation

A 39-year-old woman presented with intractably elevated intraocular pressure in the right eye. Since her intraocular collamer lens implantation surgery in 2017, her intraocular pressure had remained over 40 mmHg while using 3 types of anti-glaucoma medications. The patient had a history of phacoemulsification and posterior chamber phakic intraocular lens implantation for complicated cataracts secondary to uveitis in 2006. On gonioscope examination, there were signs of pigment dispersion, and the anterior chamber angle was open. Ultrasound biomicroscopy examination showed contact and rubbing between the intraocular collamer lens and posterior surface of the iris. And typical advanced glaucomatous optic neuropathy and visual field defects were observed. Transscleral cyclophotocoagulation was performed to control the intraocular pressure and prevent further visual field loss. However, the intraocular collamer lens was displaced after transscleral cyclophotocoagulation, which resulted in formation of a shallow anterior chamber 1 week later, angle closure and loss of intraocular pressure control 1 month later, even though the maximum dose of anti-glaucoma medication was used. Finally, an Ahmed glaucoma valve was successfully implanted in her anterior chamber, and the glaucoma was controlled, as observed at the 10-month follow-up.

Conclusions

Pigment dispersion is a common phenomenon after intraocular collamer lens implantation and may accelerate the progression of glaucoma. Transscleral cyclophotocoagulation should be carefully considered in glaucoma patients with elevated intraocular pressure after intraocular collamer lens implantation, given that transscleral cyclophotocoagulation may cause intraocular collamer lens displacement.

PRESBYOPIA MANAGEMENT WITH DIFFRACTIVE PHAKIC POSTERIOR CHAMBER IOL

OBJECTIVE

To evaluate safety and refractive efficiency after posterior chamber diffractive implantable phakic contact lens (IPCL) surgery.

MATERIAL AND METHODS

A prospective non-randomized case-series study was performed on 54 myopic eyes of 27 patients who had undergone diffractive IPCL surgery. Corneal endothelial cell density (ECD), central corneal thickness (CCT), intra-ocular pressure (IOP), vault, uncorrected distance (UDVA), spherical equivalent (SE) and defocus curve, were all evaluated twelve months after surgery. The presence of cataracts was evaluated by slit-lamp during a postoperative follow-up.

RESULTS

Mean age was 47 ± 2.62 years-old. Mean SE decreased, from -5.95 ± 2.56 D in a pre-operative stage, to -0.25 ± 0.25 D twelve months after surgery. Achieved UDVA was 20/20 in 24.1% of all cases, 20/25 in 74.1% of them, and 20/32 in all remaining cases. No eyes suffered lost lines of vision. The binocular defocus curve was 0.06 ± 0.05 logMAR for a -3.0 D of defocus; 0.11 ± 0.04 logMAR for a -1.5 D of defocus, and 0.08 ± 0.03 logMAR for a 0 D of defocus. Twelve months after surgery, mean ECD had decreased by 1.43 %, whereas mean CCT had increased by 0.06 %, without any significant statistical difference (p = 0.28 and p = 0.93 respectively). No difference (p: 0.86) in the vault was observed at 6 months vs.12 months, as well as between IOP measurements (p = 0.22). There were no non-intra or postoperative complications, and, specifically, no cataracts developed either.

CONCLUSIONS

Diffractive IPCL was implanted safely. Corneal endothelial CD, CCT, vault, and IOP remained stable twelve months after surgery. Visual acuity for distance, intermediate and near sight were achieved without spectacles.

Myopia

Myopia, also known as short-sightedness or near-sightedness, is a very common condition that typically starts in childhood. Severe forms of myopia (pathologic myopia) are associated with a risk of other associated ophthalmic problems. This disorder affects all populations and is reaching epidemic proportions in East Asia, although there are differences in prevalence between countries. Myopia is caused by both environmental and genetic risk factors. A range of myopia management and control strategies are available that can treat this condition, but it is clear that understanding the factors involved in delaying myopia onset and slowing its progression will be key to reducing the rapid rise in its global prevalence. To achieve this goal, improved data collection using wearable technology, in combination with collection and assessment of data on demographic, genetic and environmental risk factors and with artificial intelligence are needed. Improved public health strategies focusing on early detection or prevention combined with additional effective therapeutic interventions to limit myopia progression are also needed.

Phakic intraocular lenses: An overview

Phakic intraocular lenses (pIOLs) are a common solution for the surgical correction of high myopia and myopia in thin corneas. Global trends result in increasing rates of patients with high myopia which will result in increased rates of pIOL implantation. Three types of lenses can be distinguished: anterior chamber angle-supported, anterior chamber iris-fixated, and posterior chamber phakic IOLs. The efficacy of phakic intraocular lenses is generally very good, but pIOLs have undergone many changes over the years to improve the safety profile and decrease pIOL-related complications such as endothelial cell loss, corneal decompensation and cataract formation. This article describes the efficacy and safety profiles of the most recent pIOLs, as well as suggests gaps of knowledge that are deserve additional research to optimize the results of pIOLs.

Phakic intraocular lens implantation for the correction of hyperopia

The prevalence of myopia is much higher than hyperopia. Hence, there are relatively few studies investigating phakic intraocular lens (pIOL) implantation for the correction of hyperopia. This review aimed to summarize the available relevant literature on the efficacy and safety of pIOL implantation for the correction of hyperopia and hyperopic astigmatism. At present, two types of pIOLs are used to correct hyperopia and hyperopic astigmatism: anterior chamber iris-fixated pIOLs and posterior chamber implantable collamer lenses. Both have been found to be safe and effective. No serious events (eg, retinal or choroidal detachment, endophthalmitis) were reported in the reviewed articles. Implantation of pIOLs might be the optimal refractive surgery for the correction of high hyperopia.

Long-term In Vivo Stability of Posterior Chamber Phakic Intraocular Lens: Properties and Light Transmission Characteristics of Explants

PURPOSE

To evaluate the in vivo durability of the surface and optical properties of the implantable Collamer lens (ICL).

DESIGN

Retrospective case series.

METHODS

We included patients who developed cataracts after having undergone ICL implantation from March 2003 to May 2014 and underwent ICL explantation followed by cataract surgery from March 2017 to December 2019 at the Nagoya Eye Clinic. ICL explants were submitted to Chukyo Medical Co, Ltd (Nagoya City, Japan) for laboratory analysis using ultraviolet-visible light spectroscopy, light microscopy (LM), and scanning electron microscopy. Patients' demographic and clinical data were collected and reviewed.

RESULTS

Thirteen eyes from 10 patients were studied. The average age at ICL explantation was 50.5 ± 8.5 years (range, 34.5-66.3 years). The average length of ICL stay in the eye (from implantation to explantation) was 10.5 ± 2.7 years (range, 4.4-13.7 years). No opacification or coloring of the ICL explants was observed by LM. The ICL explants showed almost the same light transmittance as that of unused ICLs. Scanning electron microscopy revealed no irregularities at the surface of the center and periphery of the optic and haptic footplate. The positioning holes did not show any deposition.

CONCLUSION

The ICLs remained in-eye for >10 years without any deterioration in the surface and optical properties of the ICL, despite their contact with the ciliary body and iris tissues and the continuous interaction with the aqueous humor components. The present study shows long-term in vivo stability of the ICL.

Safety and visual outcomes following posterior chamber phakic intraocular lens bilensectomy

Background

To 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.

Methods

This 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.

Results

There 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).

Conclusions

Good 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.

Acute Angle Closure Following Implantable Collamer Lens for Myopia

We report a case of acute angle closure with significantly elevated intraocular pressure 9 hours after implantation of a phakic intraocular lens for high myopia.

Refractive outcomes of implantation of an implantable phakic copolymer lens with peripheral holes in the intraocular posterior chamber in moderate to high myopia patients: a single-surgeon series

Purpose

To assess the safety and efficacy of implanting implantable phakic copolymer lenses (IPCLs) with peripheral optic holes in the intraocular posterior chamber in Indian patients with moderate to high myopia.

Methods

Seventy-five eyes of 50 patients who underwent IPCL implantation were retrospectively analyzed. Preoperative parameters, such as subjective refraction, anterior chamber depth (measured using a pentacam), and white-to-white diameter were measured. A custom-made IPCL using the aforementioned parameters was then implanted in the sulcus to correct moderate to high myopia. All patients had undergone neodymium-doped yttrium aluminum garnet peripheral iridotomy.

Results

Clinical outcome data were collated retrospectively from the medical case records of the patients. The mean age was 25.36 years (standard deviation [SD]: 3.60 years), and 55.55% of the patients were men. The mean preoperative best-corrected visual acuity (BCVA) was 0.367 logmar units (SD: 0.266, max: 0.0 and min: 1.2). The post-IPCL implantation mean uncorrected visual acuity was 0.225 logmar units (SD: 0.172, max: 0 and min: 0.7), which was significantly superior to the preoperative BCVA (P=<0.0001). Forty-three patients (86%; satisfaction scores of ≥4; scale 1-5) were "highly satisfied" to "extremely satisfied" with the outcome. The mean follow-up period was 1.8 years.

Conclusion

Implantation of the IPCL with peripheral holes in the intraocular posterior chamber resulted in a clinically significant improvement in unaided visual acuity. Long-term follow-up showed optimum stability of vision.

Initial Results From a New Model of Posterior Chamber Implantable Phakic Contact Lens: IPCL V2.0

The aim of this study was to evaluate the corneal safety, intraocular pressure (IOP), vault and refractive efficiency of the new implantable phakic contact lens, IPCL V2.0 (Care Group, India). A prospective case series study was performed to evaluate 100 consecutive surgeries with IPCL V2.0 (spherical and toric models). Refractive results, corneal endothelial cell density (CD) and central corneal thickness (CCT) were measured at baseline and 6 months after surgery. Intraocular pressure was measured at baseline, 1 day and 6 months, and vault, 3 and 6 months after surgery. Surgical complications and cataract development were also evaluated. The mean corneal endothelial CD decreased by 2.9% with a statistically significance difference (p: 0.03). The mean CCT decreased by 0.87% at 6 months postoperative, without a statistical significance difference (p: 0.35). The mean ± standard deviation (SD) of IOP at baseline was 13.72 ±1.4 mm Hg, at 1 day postoperative was 13.88 ±1.2 mm Hg, and at 6 months was 13.62 ±1.3 mm Hg. These differences were not statistically significant (p: 0.37). The difference in vault between 3 and 6 months after surgery was not statistically significant (p: 0.97). The coefficient of correlation between the attempted versus achieved spherical equivalent (SE) change was R²: 0.958. Postoperative SE was between -0.50 D to +0.50 D in 52% of cases. The remaining of the eyes had SE values ranging from -1.5 D to +1.35 D. No intra or postoperative complications occurred and specifically cataract was not developed. The corneal endothelial CD, CCT, vault and IOP remained stable 6 months after surgery. Refraction was improved and the IPCL V 2.0 was implanted safely.

Advanced pigment dispersion glaucoma secondary to phakic intraocular collamer lens implant

Purpose

We report a case of pigment dispersion glaucoma secondary to uncomplicated phakic intraocular collamer lens (ICL) (Visian ICL™, Staar Inc., Monrovia, CA) implant that resulted in advanced visual field loss.

Observations

A 50-year-old man presented for routine follow-up status post bilateral phakic intraocular collamer lens (ICL) placement 8 years earlier. He was incidentally found to have a decline in visual acuity from an anterior subcapsular cataract and elevated intraocular pressure (IOP) in the left eye. There were signs of pigment dispersion and no evidence of angle closure. Diffuse optic nerve thinning was consistent with advanced glaucomatous visual field defects. Pigment dispersion was also present in the patient's right eye, but without elevated IOP or visual field defects. The patient was treated with topical glaucoma medications and the phakic ICL in the left eye was removed concurrently with cataract surgery to prevent further visual field loss.

Conclusions and importance

Pigment dispersion glaucoma is a serious adverse outcome after phakic ICL implantation and regular post-operative monitoring may prevent advanced visual field loss.

Colony stimulating factor-1 receptor is a central component of the foreign body response to biomaterial implants in rodents and non-human primates

Host recognition and immune-mediated foreign body response to biomaterials can compromise the performance of implanted medical devices. To identify key cell and cytokine targets, here we perform in-depth systems analysis of innate and adaptive immune system responses to implanted biomaterials in rodents and non-human primates. While macrophages are indispensable to the fibrotic cascade, surprisingly neutrophils and complement are not. Macrophages, via CXCL13, lead to downstream B cell recruitment, which further potentiated fibrosis, as confirmed by B cell knockout and CXCL13 neutralization. Interestingly, colony stimulating factor-1 receptor (CSF1R) is significantly increased following implantation of multiple biomaterial classes: ceramic, polymer and hydrogel. Its inhibition, like macrophage depletion, leads to complete loss of fibrosis, but spares other macrophage functions such as wound healing, reactive oxygen species production and phagocytosis. Our results indicate that targeting CSF1R may allow for a more selective method of fibrosis inhibition, and improve biomaterial biocompatibility without the need for broad immunosuppression.

Comparison of the Orbscan II topographer and the iTrace aberrometer for the measurements of keratometry and corneal diameter in myopic patients

Background

The purpose of this study was to compare corneal power and horizontal corneal diameter (white-to-white [WTW] distance) readings obtained by the Orbscan II topographer and the iTrace aberrometer.

Methods

Keratometry readings in the flat (Kf) and steep (Ks) meridians and WTW distance were measured with the Orbscan II and iTrace systems in 100 myopic patients. Statistical evaluation was performed using the paired t test, Pearson correlation, and Bland-Altman analysis for comparison of measurement techniques.

Results

The mean keratometry values with the Orbscan II and iTrace were 43.16 ± 1.44 and 42.64 ± 1.43 diopter (D), respectively (P < 0.0001). The mean WTW distance measurements with the Orbscan II and iTrace were 11.57 ± 0.34 and 11.33 ± 0.36 mm, respectively (P < 0.0001). For the measurement of corneal power, the 95 % limits of agreement (LoA) between the Orbscan II and iTrace were − 0.21 to 1.21 D for the flat meridian and − 0.15 to 1.25 D for the steep meridian. For the measurement of WTW distance, the range of the 95 % LoA between the two devices was 0.47 mm.

Conclusions

For some clinical applications, the keratometry and WTW distance measurements obtained by the Orbscan II topographer and the iTrace aberrometer differed greatly and therefore were not interchangeable.

Trial registration

Clinical trials number: ChiCTR-OCS-14005077 (August 2nd, 2014).

Urrets-Zavalia syndrome after implantable Collamer lens placement

We describe the case of a healthy 28-year-old woman who underwent implantation of a posterior chamber, phakic, toric, implantable Collamer lens (ICL) in both eyes for correction of bilateral high myopia with astigmatism. On the first postoperative day the patient developed increased intraocular pressure (IOP) and a fixed, mid-dilated pupil in her left eye. The elevated IOP was corrected within 3 days by medical treatment. However, the pupil remained mid-dilated and nonreactive to both light and accommodative effort during 2 months of follow-up; there was no reaction to pilocarpine (0.125% or 4%) eyedrops. The patient was diagnosed with Urrets-Zavalia syndrome (UZS), which has been reported in association with ICL implantation only once previously.

[Scheimpflug photography for the examination of phakic intraocular lenses]

BACKGROUND

High myopia phakic intraocular lenses (IOL) have become an established means of surgical correction for high ametropia. Scheimpflug photography is one of the methods which are frequently applied for postoperative examination of the implants.

MATERIAL AND METHODS

Results from published studies employing Scheimpflug photography for examination of anterior chamber angle-fixated, iris-fixated and sulcus-fixated phakic IOLs were evaluated.

RESULTS

In several published studies Scheimpflug photography was used to examine the position of the implant and opacification of the crystalline lens. The results provided valuable evidence for the improvement of phakic IOL design.

CONCLUSION

Scheimpflug photography offers an easy to use, rapid non-contact examination of phakic IOLs.

Fixed mydriatic pupil associated with an intraocular pressure rise as a complication of the implant of a Phakic Refractive Lens (PRL)

We describe a case report of a patient that was implanted with a posterior chamber phakic intraocular lens (Phakic Refractive Lens, PRL) for the correction of moderate myopia and who developed postoperatively a fixed mydriasis compatible with an Urrets-Zavalia Syndrome (UZS). Specifically, a sudden acute increase of IOP in the left eye was observed in the immediate postoperative period. After IOP stabilization, the refractive result was good, but a fixed and mydriatic pupil appeared. This condition led the patient to experience visual discomfort, halos, and glare associated with high levels of higher-order aberrations in spite of the good visual result. A tinted-contact lens was fitted in order to minimize those symptoms. The UZS should be considered as a possible complication after implantation of posterior chamber phakic intraocular lenses.