Effect of accommodation and pupil size on the movement of a posterior chamber lens in the phakic eye

Vault Height Is a Key Predictive Factor for Anterior Segment Measurement Error by IOLMaster 700 in Eyes With Phakic Intraocular Lens

Purpose

To identify risk factors of ocular anterior segment measurement error by the IOLMaster 700 in eyes implanted with an implantable Collamer lens (ICL).

Methods

In total, 152 patients with clear lens (152 eyes, group 1) and another 32 cataract patients (57 eyes, group 2) who underwent ICL implantation were included, and the presence of measurement error by the IOLMaster 700 was determined based on B-scan images. The risk factors for measurement error were evaluated by logistic regression, and the optimal threshold was determined using receiver operating characteristic analysis.

Results

The ICL was misidentified as the anterior surface of the crystalline lens in 51.97% of eyes (79/152) in group 1 and 80.70% of eyes (46/57) in group 2. For every 100-µm decrease in the vault height, a 3.57- and 5.78-fold increase in the risk of measurement error was observed in group 1 and group 2, respectively. We identified an optimal threshold of the vault height at 389.47 µm for predicting biometric measurement error in eyes implanted with ICL, which showed an area under the curve of 0.93 (95% confidence interval, 0.90-0.97), a sensitivity of 0.87, and a specificity of 0.86.

Conclusions

Patients with ICL implantation, particularly those with a vault height less than 389.47 µm, are at a greater risk of anterior segment biometric measurement error by the IOLMaster 700.

Translational Relevance

The threshold of vault height can help to identify high-risk patients and further optimize biometric measurement.

Comparison of Dynamic Vault Changes Following Implantation of Two Different Models of Phakic Intraocular Lenses

PURPOSE

To compare the dynamic vault range (the difference in the central vault height from scotopic to photopic light condition) after implantation of the ICL/TICL (STAAR Surgical) and Eyecryl phakic/Eyecryl phakic toric intraocular lens (IOL) (Biotech Healthcare).

METHODS

This retrospective study included patients with myopia or myopic astigmatism eligible for phakic IOL implantation with either the ICL/TICL or Eyecryl phakic/Eyecryl phakic toric IOL. Vault changes in varying light conditions (scotopic, mesopic, and photopic) were assessed using an anterior segment optical coherence tomography-based tomographer and dynamic vault range (DVR) was compared between the two groups.

RESULTS

A total of 60 eyes from 36 patients (30 eyes in each group) with a mean age of 28.63 ± 6.36 years were included. The mean postoperative follow-up at the time of assessment was 9.4 ± 5.3 and 8.9 ± 5.28 months (P = .75) in the ICL and Eyecryl groups, respectively. The mean values of scotopic, mesopic, and photopic vault were 490.56 ± 238.64, 453.56 ± 224.30, and 373.96 ± 200.24 μm in the ICL group and 515.46 ± 174.34, 490.26 ± 184.04, 450.43 ± 173.92 μm in the Eyecryl group (P = .32, .24, and .05, respectively). The DVR was 116.6 ± 59.29 μm in the ICL group versus 65.03 ± 31.78 μm in the Eyecryl group (P < .001).

CONCLUSIONS

The Eyecryl phakic IOL showed significantly fewer light-induced changes in the central vault height (DVR) compared to the ICL, which may be attributed to the difference in the material of the two phakic IOL models. This may be clinically significant in eyes with low postoperative vaults with respect to their follow-up and risk assessment of cataractogenesis in the long term. [J Refract Surg. 2023;39(8):546-554.].

Dislocation of implantable collamer lens following blunt trauma

Purpose

to present the signs, symptoms and management of two cases of traumatic dislocation of implantable collamer lens (ICL) after direct blunt trauma.

Observations

at presentation, we noted diffuse conjunctival hyperemia, and clear cornea in the right eye of the first patient. The anterior chamber showed +2 pigmented cells, a distorted, nasally peaked pupil with one-foot plate in front of the iris. The second case had a dislocation of the inferonasal footplate into the anterior chamber without endothelial touch.

Conclusions and importance

Dislocation of an implantable collamer lens (ICL) is rare but carries the risk of long-term complications, particularly after trauma. Ophthalmologists should identify dislocation and timely intervention can mitigate the risk of complications.ICL dislocation can be vision threatening. Ophthalmologists should identify dislocation and timely intervention can mitigate the risk of complications.

Effects of lighting conditions and accommodation on the three-dimensional position of Visian implantable collamer lens

Background

To investigate the effects of lighting conditions and accommodation on the three-dimensional position of Visian implantable collamer lens (ICL V4c).

Methods

This observational study recruited 62 eyes of 31 myopia patients underwent ICL V4c implantation. Anterior segment optical coherence tomography (AS-OCT) assessed the anterior chamber depth (ACD), ACD-ICL (distance from the corneal endothelium to anterior surface of the ICL V4c), vault (distance between the posterior ICL V4c surface and anterior crystalline lens surface), and crystalline lens tilt under various lighting conditions and accommodation relative to the corneal topographic axis at one year after ICL V4c implantation. Baseline was defined as the scotopic condition, which was also the non-accommodative stimulus condition. The ICL V4c tilt was analyzed using MATLAB. The significance level was set at P < 0.05.

Results

The ACD-ICL values were similar under various lighting conditions (P = 0.978) but decreased during accommodation (P < 0.001). The vault was significantly smaller under mesopic and photopic conditions than the baseline (P = 0.044 and P < 0.001, respectively) but remained unchanged during accommodation (P = 0.058). The inferotemporal proportion of ICL V4c (88.7%, 55 eyes) and crystalline lens (74.2%, 46 eyes) tilts were not significantly different (P = 0.063). Crystalline lens under various lighting conditions and accommodation exhibited similar tilts. The vertical tilt of ICL V4c was significantly larger under photopic conditions than the baseline (P = 0.038). The horizontal and total tilts were significantly decreased during accommodation (P = 0.043 and 0.013, respectively).

Conclusions

The axial position of ICL V4c in the anterior chamber was stable under various lighting conditions. Lighting conditions and accommodation may influence vertical, horizontal and total tilts of ICL V4c.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40662-022-00313-2.

Analysis of perioperative problems related to intraocular Implantable Collamer Lens (ICL) implantation

PURPOSE

To introduce a modified procedure of ICL implantation, to summarize the perioperative problems and their corresponding treatment after myopia correction with Implantable Collamer Lens (ICL), and to compare the difference of complications between the no-hole ICL and hole ICL.

METHODS

We searched all articles on ICL-related perioperative problems and their corresponding treatment in Scopus, Embase, PubMed and Web of Science databases for the last 22 years.

RESULTS

ICL implantation is safe, effective, stable and predictable in the correction of myopia, hyperopia and astigmatism, but can also cause a series of perioperative problems, including intraoperative and postoperative complications.

CONCLUSION

There are many kinds of complications related to ICL, but the common intraoperative and postoperative complications mainly include abnormality of arch height, abnormal position of ICL, loss of corneal endothelial cells and corneal decompensation, high intraocular pressure and secondary glaucoma, cataract and night vision symptoms. Compared with ICL without central pore, the incidence of complications such as loss of corneal endothelial cells and corneal decompensation, high intraocular pressure and secondary glaucoma and cataract was relatively lower in central hole ICL, while postoperative complications such as night vision symptoms were obvious.

Effect of Light Conditions and Accommodation on Implantable Phakic Contact Lens Vault by Anterior Segment Optical Coherence Tomography

Purpose

To investigate the dynamic pupil and vault changes in eyes with implantable phakic contact lens (IPCL) under photopic and scotopic settings, as well as during accommodation using the anterior segment optical coherence tomography (AS-OCT).

Methods

A prospective observational study included consecutive 36 eyes of myopic patients who underwent IPCL V2.0 implantation. Under photopic and scotopic light settings, as well as during accommodation, all patients were scanned using CASIA OCT (CASIA2; TOMEY, Nagoya, Japan). The pupil size, the vault (distance between the back surface of the IPCL and the anterior lens capsule), ACD-lens (distance between the posterior corneal surface and the anterior lens surface), IPCL-lens (distance between the posterior corneal surface and the anterior IPCL surface), and lens thickness (LT) were the study parameters.

Results

The vault was significantly lower under photopic conditions (p-value<0.001). The pupil size was significantly smaller in photopic conditions (p-value<0.001). LT (p-value=0.975) and ACD-lens (p-value=0.917) were not significantly different between scotopic and photopic conditions, while the ACD-IPCL was significantly larger during photopic conditions (p-value=0.013). There were significant changes in all parameters between accommodative and non-accommodative conditions.

Conclusion

The IPCL vault decreased significantly under photopic light conditions and accommodation.

Vault changes and pupillary responses to light in myopic and toric implantable collamer lens

BACKGROUND

Achieving an appropriate vault is the main concern after the implantation of Implantable Collamer Lens (ICLs) for surgical correction of high myopia. The vault will vary with time and optical parameters, such as accommodation and pupil size. This research is to evaluate the vault change in Myopic and Toric ICLs under different lighting conditions; and to analyze the relationship between vault changes and pupillary responses to light.

METHODS

We enrolled and analyzed 68 eyes from 68 patients who were implanted with Myopic EVO ICLs; we also included 60 eyes from 60 patients who were implanted with Toric EVO ICLs. The anterior chamber depth, pupil size and the post-operative vault were evaluated, 1 week after the operation, using a Visante Optical Coherence Tomography (OCT) under different lighting conditions. For each eye that was assessed, we calculated the vault change, which is defined as the difference between vault under mesopic condition and photopic condition; and the rate of vault change, which is defined as the vault change divided by mesopic vault.

RESULTS

No significant difference was noted with the anterior chamber depth between mesopic and photopic conditions in either group. A significant decrease in vault and pupil size was detected under photopic condition in both groups. We found no difference in vault change between Myopic and Toric EVO ICLs under different lighting conditions. Moreover, the rate of vault change had a significant decrease with increased mesopic vault (baseline value).

CONCLUSIONS

Too low a mesopic vault has a big rate of vault change, which may cause the contact of ICL with crystalline lens in photopic state; Too high a mesopic vault would constrict the posterior movement of pupil. The findings of the study suggest that, for patients with high or low vault, we should be more careful and must perform checks in different lighting conditions.

Effect of pupil size on posterior chamber phakic intraocular lens vault measurements

Purpose

The aim of this study was to measure the implantable collamer lens (ICL) vault changes with anterior segment optical coherence tomography (AS-OCT) after the implantation of the Visian posterior chamber phakic ICL with a central hole (V4c) in relation to the pupil size.

Methods

This retrospective observational pilot study included 32 eyes of 16 patients, who underwent V4c ICL implantation. ICL vault was measured with AS-OCT in undilated and fully dilate state of the pupil. Primary outcome measure was the change in the vault of V4c ICL at the maximum and minimum pupil size.

Results

Median (IQR) undilated and post-dilated vault measurement was 393.00 (335.50-493.50) microns and 421.00 (338.50-503.75) microns, respectively, which was not statistically significant (P = 0.44).

Conclusion

No statistically significant difference was observed between the undilated and post-dilated ICL vault measurements. Hence, the postoperative vault can be measured either in resting, undilated state or fully dilated state of the pupil and would be similar irrespective of the pupil size.

Accommodative response to ocular surface pain

CLINICAL RELEVANCE

The discovery of an accommodative response to ocular surface stimulation could inform clinicians and patients that optical effects may occur due to ocular discomfort and perhaps an assessment of the accommodative system after carrying out interventions impacting the ocular surface, may be warranted.

BACKGROUND

There have been no previous reports evaluating the effect of noxious stimulation on accommodation. Here, the accommodative response of healthy participants after the application of noxious corneal stimulation is characterised.

METHODS

A computerised Belmonte pneumatic esthesiometer was used to determine detection thresholds (using ascending method of limits), and to randomly deliver mechanical and chemical stimuli from levels of detection threshold to twice the threshold in 50% steps, to the central cornea of 15 healthy subjects. For each suprathreshold stimulus, accommodative and pupil responses were measured with a validated eccentric infrared photorefractor. Quantitative differences in accommodative/pupil response, stimulus modality/intensity and left/right eye were analysed using repeated measures ANOVA. Tukey HSD tests were used for all post hoc analyses.

RESULTS

Accommodation increased from baseline as the corneal apical stimulus intensity increased. This happened regardless of whether mechanical or chemical stimulation occurred (ANOVA, p < 0.05). At 200% threshold, accommodative response was greater than all stimulus intensities (Tukey HSD, all p < 0.05). There was no difference in pupil response between the stimulation intensities (100%, 150% and 200% threshold). There was no difference in accommodative response between the left and right eye for mechanical (ANOVA, p > 0.05) and chemical stimulation (ANOVA, p > 0.05).

CONCLUSION

Noxious stimulation of the cornea seems to produce a dose-dependent increase in the accommodative response in the eyes but not a dose-dependent pupil response.

Agreement between optical coherence and Scheimpflug tomography: Vault measurements and reproducibility after implantable collamer lens implantation

PURPOSE

To evaluate the agreement between Scheimpflug tomography (Pentacam, Oculus) and anterior segment optical coherence tomography (AS-OCT, RTVue 100, Optovue) as well as the reproducibility of each technique in assessing the lens-ICL distance (vault) after implantable collamer lens (ICL) implantation.

METHODS

The vault was measured manually with Scheimpflug tomography and AS-OCT. Intraclass correlation coefficients (ICC) and Bland-Altman plots were used to determine the reproducibility of measurements and the agreement between them. Multivariate regression analysis was performed to identify predictors of differences in vault measurements between devices.

RESULTS

80 eyes of 46 ICL patients were analyzed. Mean patient age was 33.8±7.4 years (range, 21 to 51), and 27 (59%) were women. The preoperative spherical equivalent refraction ranged from -26 to 8.5 diopters (D). The mean vault measured by AS-OCT was 558.8±240.2μm (range, 162 - 1220) vs. 430.1±215.3μm (range, 0 to 1070) by Pentacam. AS-OCT yielded vault values, on average, 128.1±64.6μm higher than the Pentacam (range, -22 to 293μm). The ICC values for consistency and absolute agreement were 0.960 and 0.928, respectively. Reproducibility of vault measurements was excellent for both devices (ICC≥0.946). Four parameters-vault, pupil diameter (PD), PD differences between devices, and preoperative spherical equivalent refraction-were significant predictors of differences in vault measurements (adjusted-R²=0.412; P<0.001).

CONCLUSIONS

Agreement between AS-OCT and Pentacam for vault measurement was good. Vaults were higher when measured by AS-OCT. These differences are clinically relevant, and therefore these devices cannot be used interchangeably to measure vault.

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.

Vault changes after cyclopentolate instillation in eyes with posterior chamber phakic intraocular lens

Posterior chamber phakic intraocular lens (pIOL) implantation is a common option for correcting moderate-to-high ocular refractive defects. Because this pIOL is implanted on ciliary sulcus, the distance between the back surface of the pIOL and the anterior surface of the crystalline lens, that it is known as vault, should be measured in different conditions to ensure the technique's safety. Cyclopentolate is a drug that dilates the pupil and relaxes accommodation (cycloplegia). It is often used for different ocular examinations and for other medical purposes. However, there is no evidence of the effect of this drug on vault. This study quantified central vault changes associated with cyclopentolate instillation. We measured the vault under normal conditions (pre-cycloplegic instillation) and after instilling cyclopentolate on 39 eyes of 39 patients with implanted pIOL. Our results suggest that cyclopentolate instillation may induce changes to vault in eyes with implanted pIOL. These changes seem safe and are mainly associated with vault under normal conditions, but also with anterior chamber depth, pupillary diameter and pIOL size.

Vault Changes Caused by Light-Induced Pupil Constriction and Accommodation in Eyes With an Implantable Collamer Lens

PURPOSE

An appropriate vault after implantation of a posterior chamber phakic intraocular lens with a central hole (ICL KS-AP) is important for successful long-term outcomes. In the present study, we used anterior segment optical coherence tomography (AS-OCT) to examine dynamic pupil and vault changes under photopic and scotopic conditions and during accommodation in eyes with ICL KS-AP.

METHODS

This retrospective study included patients at an outpatient ophthalmology clinic who underwent ICL KS-AP implantation >1 month before enrollment. All patients underwent dynamic AS-OCT imaging under photopic and scotopic conditions. Patients aged <40 years also underwent imaging in the accommodative and nonaccommodative states. Primary outcome measures were the pupil size and vault at the maximum and minimum pupil sizes.

RESULTS

This study included 91 eyes of 47 patients (35.5 ± 8.6 years, 21 men). Accommodation was examined in 51 eyes of 26 patients (28.9 ± 5.0 years, 10 men) younger than 40 years. The pupil size was significantly smaller under photopic conditions (3.64 ± 0.77 mm) than under scotopic conditions (4.91 ± 0.75 mm, P < 0.001) and during accommodation (3.88 ± 0.64 vs. 4.10 ± 0.61 mm, P < 0.001). Vault was also significantly lower under photopic conditions (476.1 ± 219.6 μm) than under scotopic conditions (521.1 ± 220.4 μm, P < 0.001) and during accommodation (454.8 ± 224.9 vs. 481.6 ± 219.1 μm, P < 0.001).

CONCLUSIONS

Vault can be significantly lowered by light-induced pupil constriction and accommodation in eyes with ICL KS-AP.

Advances and challenges of intraocular lens design [Invited]

Phacoemulsification technique with intraocular lens implantation has been a common treatment for cataract patients. With rising demand among the public, new technologies for lens design have emerged to minimize intraocular aberrations, improving visual quality to the largest extent. This paper systematically reviews the development of materials applied in lens manufacturing, the different categories of intraocular lenses, and respective design principles. The advantages and potential drawbacks of intraocular lenses are illustrated in the paper, and prospective research to improve the design are presented in the end.

Analysis of intraocular positions of posterior implantable collamer lens by full-scale ultrasound biomicroscopy

Background

To analyze the positions of intraocular posterior Implantable Collamer Lens (ICL) and its possible relationship with vault.

Methods

This cross-sectional study included 72 patients with high myopia (134 eyes) who were followed up after phakic intraocular lens implantation. The postoperative time ranged from 1 week to 7 years. We obtained the images of ICL by using Compact Touch STS UBM and observed the position of ICL in posterior chamber and ciliary sulcus. The horizontal lines vault was measured and recorded.

Results

There were various positions in the posterior chamber as observed by full-scale ultrasound biomicroscopy and the haptics were inserted at different positions. -Eight seven eyes (64.9%) that obtained ideal vault, 29 eyes (21.6%) had insufficient vaults and 18 eyes (13.4%) had excessive vault. The vault with various positions of haptics was in ideal range (250 μm–750 μm) almost in each group. Three eyes in this study with haptics on the top of ciliary sulcus obtained excessive vault (mean vault, 850.00 ± 70.71 μm) and one eye appeared one side haptics pushing forward the iris. Among five eyes (3.7%) with iridociliary body cysts, three eyes (60%) obtained ideal vault. One eye (0.7%) with ICL decentralization after implantation surgery had an ideal vault, but the patient had serious glare.

Conclusions

Though ICL in the posterior chamber had different positions and the haptics in most cases were not in the ciliary sulcus, the postoperative vault was almost in the ideal range.

Dynamic Assessment of Light-Induced Vaulting Changes of Implantable Collamer Lens With Central Port by Swept-Source OCT: Pilot Study

Purpose

To assess dynamic variations in vault induced by changes in brightness in eyes implanted with phakic collamer intraocular lens (pIOL) with central port for correction of myopia, defining new parameters of vaulting measurement.

Methods

We used a noninvasive Fourier-domain swept-source anterior-segment optical coherence tomography (AS-OCT) system to dynamically evaluate the shifts between the pIOL and anterior chamber structures under changing light conditions. For each eye assessed, we measured vault interval (VI), which we define based on central vault values in maximum mydriasis and in maximum miosis after light-induced changes in pupil diameter, and vault range (VR), which we define as the absolute difference between the VI values.

Results

The pilot study sample comprised 39 eyes (23 patients) previously implanted (mean 107 ± 156 days) with a pIOL. A significant difference in vault value was found when maximum and minimum pupil size was assessed under changing external light conditions (P < 0.001). The mean VR from scotopic (0.5 lux) to photopic (18,500 lux) light conditions was 167 ± 70 μm.

Conclusions

Vault is continuously affected during movements of the pupil induced by external luminance.

Translational Relevance

Quantifiable dynamic parameters VR and VI obtained with this AS-OCT device describe the position of the pIOL in the posterior chamber of the eye in a more accurate and real way than static vault measurements, and may contribute to improved understanding of the behavior of the pIOL in terms of safety.

Effect of Accommodation on Vaulting and Movement of Posterior Chamber Phakic Lenses in Eyes With Implantable Collamer Lenses

PURPOSE

To investigate and compare vaulting and movement changes during accommodation in eyes with the V4c and V4 implantable collamer lenses (ICL).

DESIGN

Comparative, observational case series.

METHODS

The medical records of 35 eyes (18 patients) with the V4 ICL and 51 eyes (26 patients) with the V4c ICL were retrospectively examined and included in analyses. Anterior chamber depth (ACD), posterior corneal surface-to-ICL distance (endo-ICL distance), pupil size, and postoperative vaulting were evaluated using the Visante anterior chamber optical coherence tomography system. Images were taken during the nonaccommodative and accommodative states 3 months after ICL implantation. Refractive error, keratometry values, axial length, intraocular pressure, and central corneal thickness were evaluated at 3 months postoperatively.

RESULTS

ICL vaulting did not significantly change during accommodation in eyes with either the V4 or V4c ICL (P = .532 for V4 ICL and P = .415 for V4c ICL). However, significant reductions in ACD, endo-ICL distance, and pupil size were observed during accommodation in both groups. In eyes with a V4 ICL, the change in [Δ] ACD was 0.2 ± 0.1 mm (P < .001), Δendo-ICL distance was 0.2 ± 0.1 mm (P < .001), and Δpupil size was 0.5 ± 0.9 mm (P = .021). For eyes with the V4c ICL, ΔACD was 0.2 ± 0.2 mm (P < .001), Δendo-ICL distance was 0.2 ± 0.2 mm (P < .001), and Δpupil size was 0.8 ± 1.2 mm (P < .001). The mean reductions of each parameter were not statistically different between eyes with the V4 ICL and the V4c ICL.

CONCLUSIONS

Contrary to the light stimulation response, accommodation does not significantly affect ICL vaulting differently in eyes with either the V4 or V4C ICLs.

Long-term ultrasound biomicroscopy observation of position changes of a copolymer posterior chamber phakic intraocular lens

PURPOSE

To evaluate longitudinal changes in Implantable Collamer Lens phakic intraocular lens (pIOL) position after implantation.

SETTING

Department of Ophthalmology, Zhejiang University, Hangzhou, China.

DESIGN

Retrospective case series.

METHODS

Myopic eyes that had pIOL implantation with a follow-up of at least 24 months were evaluated. Ultrasound biomicroscopy examinations were performed at each visit.

RESULTS

The study enrolled 62 eyes (31 patients; 22 women, 9 men) ranging in age from 21 to 46 years. The manifest spherical equivalent ranged from -8.25 to -18.75 diopters. A significant increase (mean 36 μm±50 [SD]) in the endothelium-anterior pIOL distance occurred between 1 month and 3 months (P=.000); afterward, the distance decreased slowly (P>.05). The largest decrease (mean 47±17 μm) in central vault occurred between 1 month and 3 months (P=.009). The largest decrease (mean 21±14 μm) in peripheral vault occurred between 1 month and 3 months (P=.000).

CONCLUSIONS

A significant increase in the endothelium-anterior pIOL distance occurred from 1 month to 3 months postoperatively, after which a slight decrease occurred over time. Central vault and peripheral vault had a tendency to decrease over time.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Dynamic vaulting changes in V4c versus V4 posterior chamber phakic lenses under differing lighting conditions

PURPOSE

To compare vaulting changes in eyes implanted with V4c and V4 implantable collamer lenses (ICLs) under differing lighting conditions.

DESIGN

Noninterventional, cross-sectional comparative observational case series.

METHODS

Fifty-six eyes of 38 patients implanted with V4c ICLs, and 54 eyes of 28 patients implanted with V4 ICLs were enrolled and analyzed. Anterior chamber depth, pupil size and postoperative vaulting were evaluated using a Visante optical coherence tomography system under photopic and mesopic conditions 1 month postoperatively. Refractive errors, keratometry values, axial lengths, intraocular pressures, anterior chamber volumes, and central corneal thicknesses were also recorded.

RESULTS

No significant differences were noted in anterior chamber depth between photopic and mesopic conditions in either group. Significant decreases in vaulting and pupil size were detected under photopic conditions in both groups. Moreover, vaulting changes in eyes implanted with V4c ICLs were significantly larger than those in eyes implanted with V4 ICLs.

CONCLUSIONS

V4c ICL vaulting decreased more prominently under photopic conditions than did V4 ICL vaulting. Therefore, postoperative vaulting under mesopic and photopic conditions should be considered when interpreting the vaulting of eyes implanted with V4c ICLs.

The effect of room illumination on the measurement of anterior segment parameters

OBJECTIVE

To evaluate the effect of room illumination on the measurement of anterior segment parameters.

METHODS

In this comparative study, measurements of anterior segment parameters of 25 eyes of 25 healthy patients were performed by optical low-coherence reflectometry (OLCR). Measurements were taken under photopic conditions (150 lux) and under mesopic conditions (3 lux). Paired t test by SPSS 16.0 was used to compare the anterior segment measurements performed in both conditions. A P value lower than 0.05 was accepted as statistically significant.

RESULTS

The mean age of the patients was 27.09±1.72 years (range, 20-40 years). Of the anterior segment parameters, axial length and keratometry did not show significant difference between photopic and mesopic conditions (P=0.541 and P=0.812, respectively). The mean anterior chamber depth measurements was 3.04±0.35 mm and 3.06±0.35 mm, whereas the mean lens thickness was 3.75±0.36 mm and 3.77±0.36 mm in the mesopic and photopic conditions, respectively. The mean pupil diameter measurement was 4.86±0.70 mm under photopic conditions and 6.36±0.94 mm under mesopic conditions. The anterior chamber depth, lens thickness, and pupil diameter showed significant difference between photopic and mesopic conditions (P=0.01, P=0.006, and P=0.0001, respectively).

CONCLUSION

Anterior chamber depth, lens thickness, and pupil diameter were affected by the changes in luminance while performing measurements with OLCR. Considering the age of the study group, further studies are needed to test the measurement of accommodation amplitude.

Rotation stability of the cachet angle-supported phakic intraocular lens

PURPOSE

To evaluate the rotational stability of an acrylic angle-supported phakic intraocular lens (PIOL) 12 months after implantation in myopic eyes.

METHODS

Patients with a history of moderate to high myopia underwent unilateral or bilateral implantation of an acrylic angle-supported PIOL (AcrySof Cachet; Alcon Laboratories, Inc., Fort Worth, TX). All were followed up for 12 months. IOL rotation was assessed using digital overlay of ocular photographs captured within 2 weeks of implantation and at postoperative month 12. The secondary outcomes of refractive power (spherical equivalent, refractive sphere, and cylinder) and uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were assessed preoperatively and again at 3 months after implantation.

RESULTS

Fifty eyes of 28 patients with a mean age of 32 years were included in this retrospective cohort study. All underwent successful IOL implantation and follow-up. A mean 12-month rotation of 11° was observed (standard deviation: 15.1°, range: 0 to 60°). All preoperative measures (mean) of refractive power improved by 3 months postoperatively (spherical equivalent = -0.35 ± 0.79 diopters [D], spherical refraction = 0.04 ± 0.82 D, and cylindrical refraction = -0.77 ± 0.91 D). Two percent of eyes requiring additional laser adjustment by postoperative month 12, primarily due to corneal astigmatism.

CONCLUSION

The study findings suggest that AcrySof Cachet angle-supported PIOLs offer moderate 1-year rotational stability. Because this type of IOL also corrects myopia effectively, it appears to be a good treatment option for myopic eyes. However, the rotation that occurs makes it unsuitable for cylinder corrections.

Anterior segment variations after posterior chamber phakic intraocular lens implantation in myopic eyes

PURPOSE

To evaluate anterior segment variations after posterior chamber phakic intraocular lens (pIOL) implantation in myopic eyes.

SETTING

Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.

DESIGN

Cohort study.

METHODS

Patients with high myopia were scheduled for nontoric Implantable Collamer Lens pIOL or toric Implantable Collamer Lens pIOL implantation. Anterior segment optical coherence tomography was performed to evaluate the anterior segment variations over time and the impact of physiologic accommodation and change in brightness after pIOL implantation. Slitlamp photography of the anterior segment was taken after pupil dilation to calculate pIOL rotation.

RESULTS

There was significantly improved visual acuity and refractive status after implantation of both pIOLs. Anterior segment axial variations had good stability 6 months postoperatively. However, nontoric pIOL rotation occurred in 1 eye 7 months postoperatively and rotation of the toric pIOL occurred in 2 eyes at 3 months and 6 months. Stimulations of -4.0 diopters (D) and -8.0 D led to significant changes in anterior chamber depth (ACD) based on the lens (ACD-lens), ACD after pIOL implantation, distance between the pIOL posterior surface and the lens anterior surface (pIOL-lens), and pupil diameter. Increasing ambient light brightness could reduce the ACD-lens and pIOL-lens.

CONCLUSIONS

Both pIOLs had good axial stability in myopic eyes 6 months postoperatively; however, rotational stability over time could not be determined. The physiologic adjustment and change in brightness could influence the anterior segment significantly in eyes with a pIOL.

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.

Changes in vaulting of myopic and toric implantable collamer lenses in different lighting conditions

PURPOSE

To evaluate the changes in vaulting of myopic and toric Implantable Collamer Lenses (ICLs) in different lighting conditions.

METHODS

Thirty-seven eyes of 37 patients implanted with a myopic ICL and 26 eyes of 26 patients implanted with a toric ICL were examined using Visante optical coherence tomography (OCT) in photopic (257 lux) and mesopic (2 lux) conditions. Pupil diameter and distance changes between the ICL and adjacent intraocular structures were measured.

RESULTS

The mean horizontal pupillary diameters in mesopic conditions were 5.3 ± 0.9 (SD) mm. In photopic conditions, a mean decrease of -1.8 ± 0.6 mm [95% confidence interval (95% CI) -2.0 to -1.7; p < 0.0001] was observed. The mean distances between the ICL and the crystalline lens in mesopic conditions were 0.33 ± 0.17 mm. In photopic conditions, a mean decrease of -0.04 ± 0.06 mm (95% CI -0.05 to -0.02; p < 0.0001) in the ICL-crystalline lens distance was found. There was a -0.02 ± 0.04 mm (95% CI -0.03 to -0.01; p = 0.0022) decrease in the anterior chamber depth and a 0.02 ± 0.06 mm (95% CI 0.002 to 0.032; p = 0.0275) increase in the distance between the cornea and the ICL. We found no difference in the change in vaulting between the two ICLs in different lighting conditions.

CONCLUSION

There is a decrease in the central vaulting of myopic and toric ICLs in photopic conditions. This is due to both posterior movement of the ICL and anterior protrusion of the crystalline lens.

Retinal detachment after phakic intraocular lens implantation in severe myopic eyes

BACKGROUND

To report the incidence, clinical presentation, and surgical outcomes of retinal detachment in highly myopic patients corrected by implantation of phakic intraocular lenses (PIOLs).

METHODS

This is a retrospective interventional non-comparative case series. A total of 530 highly myopic eyes that underwent PIOLs implantation were included in the study. All patients completed at least a 2-year follow-up after PIOL implantation. The incidence of retinal detachment (RD) and subsequent treatments were reviewed. The refractive errors, axial lengths, time between refractive surgery and RD detection, vitreoretinal findings, rate of retinal reattachment, and the pre- and postoperative best-corrected visual acuity (BCVA) were analyzed.

RESULTS

The overall incidence of RD was 1.5 % (eight eyes of seven patients) with a mean time between PIOL implantation and detachment of 23.63 ± 18.12 months (range, 2 days-51 months). Mean spherical equivalent (SE) before PIOL implantation was -17.53 ± 3.86 diopters (D) (range, -11.5D to -23.5D). Six patients underwent bilateral PIOL implantation. Five eyes were implanted with anterior chamber PIOLs and the other three received posterior chamber PIOLs. A traumatic history was presented before RD detection in four cases. Horseshoe tears, atrophic holes, or giant retinal tears were found in four (50 %), two (25 %), and two (25 %) eyes, respectively. Two eyes (25 %) underwent scleral buckling surgery, five eyes (62.5 %) underwent pars plana vitrectomy surgery, and one eye (12.5 %) underwent both procedures. Anatomical retinal attachment was achieved after first RD surgery in seven eyes. Mean BCVA after PIOL implantation and before RD was 20/40 (decimal refraction, 0.51 ± 0.31) compared to that of 20/80 (decimal refraction, 0.26 ± 0.12) after the RD surgery. Mean follow-up after RD surgery was 20.63 ± 12.93 months (range, 8-42 months).

CONCLUSIONS

The incidence of RD after PIOLs implantation is low. Its characteristics do not differ significantly from the natural history of RD in high myopic eyes. PIOL implantation for surgical correction of severe myopia does not seem to increase the risk of RD. Good visual prognosis can be obtained with early surgical intervention.

Long-term evaluation of the central vault after phakic Collamer® lens (ICL) implantation using OCT

PURPOSE

The aim of this work is to evaluate the changes in the central vault after using implantable Collamer® lenses (ICL) to correct myopia.

METHODS

This cohort study included 133 eyes; mean spherical equivalent -9.47 ± 3.71 diopters (D) (range: -2.75 to -22.25 D) who underwent ICL V4 implantation. Besides a complete ophthalmologic examination, the central vaulting was measured with Visante OCT and evaluated between different periods of follow-up (1 week, 1, 3, and 6 months, and yearly postoperatively). Post-operative time ranged from 6 to 73 months.

RESULTS

Within the first 6 months, the mean central vaulting dropped from 510 ± 238 μm (range 100 to 940 μm) to 439 ± 231 μm (range 90 to 910) a significant decrease by 71 ± 58 μm (range -170 to 30 μm) (p = 0.028) with a trend to a lower reduction after this period. After 36 month from ICL implantation, this variation tends to be smaller with the majority of the eyes having a mean decrease smaller than 2 μm per month. Initial vault (Spearman Rho = -0.237, p = 0.006) was the factor more significantly associated with decrease in vault; eyes presenting a reduction in vault >100 μm had an average initial vault that was 141 μm and 184 μm higher than eyes with no change or with increase in vault over time, respectively.

CONCLUSIONS

This study shows a continuous reduction of central vault over time. The reduction is highest during the first 6 months and tends to be lower and slow down over time. The decrease of vaulting was more pronounced in eyes with larger initial vaulting.

Central vault after phakic intraocular lens implantation: correlation with anterior chamber depth, white-to-white distance, spherical equivalent, and patient age

PURPOSE

To compare the central postoperative vault of a phakic intraocular lens (pIOL) to correct myopia, myopic astigmatism, and hyperopia and identify ocular and lens parameters that might predict the vault amount.

SETTING

Fernández-Vega Ophthalmological Institute, Oviedo, Spain.

DESIGN

Cohort study.

METHODS

Three months after implantation of Implantable Collamer Lens pIOLs to correct myopia, hyperopia, and myopic astigmatism, central vault was measured using optical coherence tomography. Patients were divided into groups according to the preoperative anterior chamber depth (ACD) to compare the effects of ACD, white-to-white (WTW) distance, and lens diameter on postoperative pIOL vault.

RESULTS

Hyperopic pIOLs had statistically significantly lower vault followed by myopic pIOLs and toric pIOLs, which had a higher mean value and narrower range (260 to 860 μm). Measured vaults had a positive correlation with preoperative ACD (r = .32, P<.001) and WTW (r = .29, P<.001) and a negative correlation with preoperative spherical equivalent (SE) (r = -0.21, P<.001) and patient age (r = -0.12, P=.025). Eyes with a vault of 250 μm or less had a shallower ACD than eyes with a vault between 250 μm and 750 μm (mean difference -0.11 mm; P=.012) and those with a vault greater than 750 μm (mean difference -0.25 mm; P<.001).

CONCLUSIONS

Central vaulting was lower in hyperopic eyes. Current nomograms for pIOL diameter selection based on ACD and WTW might yield ideal vault and may have to be adjusted for older patients, shallower ACD, lower WTW, and lower SE.

Risk factor evaluation for cataract development in patients with low vaulting after phakic intraocular lens implantation

PURPOSE

To evaluate the occurrence of cataract in eyes with low vaulting after phakic intraocular lens (pIOL) implantation for myopia and suggest guidelines for such cases.

SETTING

Samsung Medical Center, Seoul, Korea.

DESIGN

Cross-sectional study.

METHODS

Eyes with low Implantable Collamer Lens pIOL vaulting (<250 μm) were followed 1, 3, and 6 months as well as 1, 2, 3, and 4 years postoperatively. Frequency and time to cataract development were evaluated. Risk factors for cataract development were assessed using logistic regression analysis. Cutoff values for differentiating eyes at higher risk for cataract development were evaluated using Fisher exact and chi-square tests.

RESULTS

Cataract developed in 8 (30.8%) of 26 eyes (6 of 20 patients) a mean of 18.7 months ± 10.1 (SD) postoperatively. Risk factors that were significant for cataract formation included lower vaulting (mean 42.4 ± 34.0 μm versus 141.4 ± 82.2 μm; odds ratio [OR], 1.05), older age (mean 42.6 ± 7.3 versus 34.9 ± 6.9 years; OR, 1.22), and higher preoperative spherical equivalent (SE) (mean -17.1 ± 4.4 diopters [D] versus -10.7 ± 2.7 D; OR, 1.64). The optimum cutoff values were 51.7 μm, 45 years, and -14.00 D (P=.0095, P=.0367, and P=.0342 respectively).

CONCLUSION

In cases of low pIOL vaulting, close follow-up should be considered when central vaulting is less than 52 μm, patient age is more than 45 years, or the preoperative SE is greater than -14.00 D because these factors increase the risk for cataract.

Implantable collamer posterior chamber intraocular lenses: a review of potential complications

PURPOSE

To review the peer-reviewed literature reporting postoperative complications of the most recent models of Visian Implantable Collamer posterior chamber intraocular lenses (ICL, STAAR Surgical Co).

METHODS

A literature search of the PubMed database was performed to identify all articles related to ICL complications. Articles were obtained and reviewed to identify those that reported complications using the latest ICL designs.

RESULTS

Cataract was the major postoperative complication reported: 136 (5.2%) in 2592 eyes. Of those, 43.4% (n=59) were reported within 1 year, 15.4% (n=21) between 1 and 3 years, and 35.3% (n=48) ≥ 3 years after ICL implantation. Twenty-one (15.4%) cataracts were reported as surgically induced, 46 (33.8%) eyes had poor vault (<200 μm), and cataract surgery was carried out in 27.9% (n=38) of eyes. Early acute intraocular pressure increase was also reported to be relatively frequent, whereas acute pupillary block was less frequent and mostly resolved with additional iridotomies. A total of 42 ICLs were explanted due to cataract and IOP. Reported endothelial cell loss varied from 9.9% at 2 years to 3.7% 4 years postoperatively. This loss was reported to be more pronounced within the first 1 to 2 years, with stability or lower progression after that time.

CONCLUSIONS

The majority of reported complications after ICL implantation are cataract formation. The improvements in lens geometry and more accurate nomograms applied to the selection of the lens to be implanted, in addition to the surgeon's learning curve, might be factors in the decreased occurrence of postoperative complications reported currently.

Intraocular stability of an angle-supported phakic intraocular lens with changes in pupil diameter

PURPOSE

To use anterior segment optical coherence tomography (AS-OCT) to evaluate the stability of a recently released angle-supported phakic intraocular lens (pIOL) in the anterior segment with changes in pupil diameter.

SETTING

Keratoconus Unit, Vissum Corporation, Alicante, Spain.

METHODS

In this observational cross-sectional study of consecutive eyes with moderate to high myopia, an AcrySof Cachet pIOL was implanted with the aim of minimizing the refractive error. An analysis of the position and stability of the pIOL before and after pharmacologic pupil dilation was performed 3 months postoperatively using the Visante AS-OCT system. A measurement protocol that included several anatomic parameters was developed and applied; the parameter values before and after dilation were compared.

RESULTS

Twenty eyes of 20 patients ranging in age from 24 to 48 years old were evaluated. The anterior chamber depth increased significantly with pupil dilation (mean change 0.06 mm +/- 0.08 [SD]) (P<.01). A significant change was also observed in the distance between the center of the cornea at the endothelial plane and the anterior surface of the pIOL (mean change 0.03 +/- 0.05 mm) (P = .01). The distances between the peripheral edges of the pIOL and the corneal endothelium and the distance between the crystalline lens and the pIOL did not change significantly (P>or=.14).

CONCLUSION

The angle-supported pIOL showed excellent intraocular behavior after pupil dilation, with no shortening of the distance between the pIOL and corneal endothelium at the center or peripheral edges of the pIOL.

Comparison of clear lens extraction and collamer lens implantation in high myopia

Aim:

To compare the outcomes of clear lens extraction and collamer lens implantation in high myopia.

Patients and methods:

Myopic patients younger than 40 years old with more than 12 diopters of myopia or who were not fit for laser-assisted in situ keratomileusis were included. Group 1 comprised patients undergoing clear lens extraction and Group 2 patients received the Visian implantable collamer lens. Outcome and complications were evaluated.

Results:

Postoperative best corrected visual acuity was −0.61 ± 0.18 in Group 1 and 0.79 ± 0.16 in Group 2. In Group 1, 71.4% achieved a postoperative uncorrected visual acuity better than the preoperative best corrected visual acuity, while only 51.8% patients achieved this in Group 2. Intraocular pressure decreased by 12.55% in Group 1, and increased by 15.11% in Group 2. Corneal endothelial cell density decreased by 4.47% in Group 1 and decreased by 5.67% in Group 2. Posterior capsule opacification occurred in Group 1. In Group 2, lens opacification occurred in 11.11%, significant pigment dispersion in 3.7%, and pupillary block glaucoma in 3.7%.

Conclusion:

Clear lens extraction presents less of a financial load up front, and less likelihood of the need for a secondary intervention in the future. Clear lens extraction is a more viable solution in developing countries with limited financial resources.

Long-term changes in posterior chamber phakic intraocular collamer lens vaulting in myopic patients

OBJECTIVE

Evaluation of central and midperipheral vaulting of the posterior chamber phakic intraocular Collamer lens (ICL; Staar Surgical Inc., Monrovia, CA) in eyes with moderate to high myopia.

DESIGN

Retrospective analysis of prospectively collected data.

PARTICIPANTS

Eighty-four eyes treated with the latest ICL (V4 model) and 27 eyes treated with early ICL models were examined.

METHODS

After standardized ICL implantation, patients underwent complete ophthalmologic examinations before surgery and at 1 week, 1 month, 3 months, 6 months, and at yearly intervals thereafter. Central vaulting was measured using the Jaeger device (Haag-Streit, Bern, Switzerland). From 2006 onward, vaulting was measured additionally by optical coherence tomography (Visante OCT; Carl Zeiss Meditec, Jena, Germany). Using the Visante OCT, the crystalline lens rise and the midperipheral vaulting of the ICL were assessed.

MAIN OUTCOME MEASURES

Central vaulting after ICL implantation.

RESULTS

The mean duration of follow-up was 74.1+/-23.1 months and 96.3+/-50.2 months in eyes treated with V4 and early models, respectively. Postoperative central vaulting was 466+/-218 microm (range, 30-900 microm) in eyes treated with the V4 models and 321+/-200 microm (range, 150-900 microm) in those treated with early ICL models. From the 6-month follow-up onward, a continuous and nearly linear reduction of central vaulting was observed. At the 10-year follow-up, the mean central vaulting was reduced to 184+/-159 microm (range, 6-500 microm) and 138+/-218 microm (range, 0-820 microm) in eyes treated with V4 or early models, respectively. Eyes with total vaulting had a mean central vaulting of 407+/-202 microm (range, 180-730 microm), whereas those with midperipheral contact had a significantly lower central vaulting of 105+/-87 microm (range, 0-200 microm).

CONCLUSIONS

This study revealed consistent reduction of central vaulting over a 10-year period and provides further evidence that insufficient vaulting of the ICL is responsible for the development of anterior subcapsular cataract. A minimum central vaulting of 230 microm seems to be necessary to ensure total vaulting of the ICL. If an ICL is chosen for the correction of myopia, targeting for the greatest possible postoperative central vaulting is advised to achieve safe and complete vaulting for several years.

Vaulting of myopic and toric Implantable Collamer Lenses during accommodation measured with Visante optical coherence tomography

PURPOSE

To study changes in vaulting of myopic and toric Implantable Collamer Lenses (ICLs) version 4 during accommodation with Visante optical coherence tomography (OCT), and analyze the relationship between vaulting and anterior subcapsular opacification.

DESIGN

Cross-sectional study.

PARTICIPANTS

Seventy-seven eyes of 77 myopic patients were examined after implantation with an ICL (48 myopic, 29 toric). The median follow-up time was 63 months (range, 10-84).

METHODS

The distance between the posterior ICL surface and the anterior surface of the crystalline lens was measured in the nonaccommodative state and during accommodation with Visante OCT. The lenses were examined for opacification using slit-lamp microscopy.

MAIN OUTCOME MEASURES

The distance between the ICL and the anterior surface of the crystalline lens.

RESULTS

At baseline, the mean distance between the ICL and the crystalline lens was 0.31+/-0.19 mm and during accommodation 0.31+/-0.26 mm; the difference did not reach significance (P = 0.77). The distance at baseline was significantly (P = 0.01) less in older patients and significantly (P = 0.04) greater in patients with a toric ICL. Contact was observed at baseline or during accommodation in 12 eyes; there was a significantly lower incidence of contact in eyes implanted with a toric ICL (P = 0.03). Anterior subcapsular opacification developed in 10 eyes, in 5 of these the ICL touched the crystalline lens.

CONCLUSIONS

Anterior subcapsular opacification developed in 13.0% of eyes. We found no difference in vaulting of the ICL at baseline and during accommodation. There was contact between the ICL and the crystalline lens in 15.6% of the eyes. The association between anterior subcapsular opacification and contact was significant (P = 0.004).

Factors affecting vaulting after implantable collamer lens implantation

PURPOSE

To evaluate the vaulting of the STAAR Implantable Collamer Lens (ICL) over the crystalline lens after implantation.

METHODS

One hundred twenty-three eyes of 68 patients with myopic refractive errors of -3.25 to -22.75 diopters undergoing ICL implantation were examined retrospectively. The magnitude of the central vaulting of the ICL was assessed quantitatively using slit-lamp microscopy at 3 months after surgery. Multiple regression analysis was used to assess the factors affecting the amount of vaulting.

RESULTS

The mean central vaulting 3 months after surgery was 603.6 +/- 259.6 microm. Explanatory variables relevant to the vaulting were, in order of influence, the horizontal white-to-white distance (partial regression coefficient B = 0.268, P = .0002) and patient age (B = -0.007, P = .011).

CONCLUSIONS

Although the majority of the variance remains unexplained, younger patients' eyes and eyes with greater white-to-white distances are more predisposed to have higher ICL vaulting over the crystalline lens.

Time course of accommodation after implantable collamer lens implantation

PURPOSE

To assess the time course of accommodative function after Implantable Collamer Lens (ICL) implantation and to investigate the relationship between patient age and accommodation in ICL-implanted eyes.

DESIGN

Prospective, nonrandomized clinical trial.

METHODS

We prospectively examined 69 eyes of 40 consecutive patients with myopic refractive errors of -3.25 to -22.75 diopters (D) who were undergoing ICL implantation. We assessed the amplitude of accommodation using an accommodometer before and one, three, six, and 12 months after surgery. We also investigated its relationship with patient age.

RESULTS

The accommodation was 6.36 +/- 3.94 D (mean +/- standard deviation) before surgery and 4.89 +/- 2.72 D, 4.98 +/- 2.67 D, 5.16 +/- 2.72 D, and 5.72 +/- 2.85 D at one, three, six, and 12 months after surgery, respectively. The variance of data was statistically significant (P = .02, repeated-measures analysis of variance). Multiple comparisons demonstrated significant differences between measurements made before surgery and at one month after (P = .004, Fisher least significant difference test), before surgery and at three months after (P = .007), and before surgery and at six months after (P = .01). There was a significant correlation between patient age and accommodation before (Pearson correlation coefficient, r = -0.665; P < .001) and one year after (r = -0.803; P < .001) ICL implantation.

CONCLUSIONS

Accommodation was impaired transiently in the early postoperative periods, and then recovered gradually over time, indicating that transient dysfunction of the ciliary muscles by ICL fixation may occur after ICL implantation even if the crystalline lens remained intact. As patients aged, the amplitude of accommodation became significantly smaller not only in normal eyes but also in ICL-implanted eyes.

Optical Coherence Tomography of the Anterior Segment in Eyes with Phakic Refractive Lenses

PURPOSE

To evaluate the dynamics of the phakic refractive lens (PRL) in myopic and hyperopic eyes in the nonaccommodated state and during subjective accommodation with Visante optical coherence tomography (OCT).

DESIGN

Cross-sectional study.

PARTICIPANTS

Forty-one myopic eyes and 11 hyperopic eyes of 52 patients (mean age, 34 years; range, 24-49) were examined at least 1 year after PRL implantation using Visante OCT. Thirty-one myopic eyes had the PRL model 101 and 10 eyes had the smaller PRL model 100 implanted. The hyperopic model, PRL 200, is available in only one size.

METHODS

Noninvasive high-resolution anterior OCT was used to measure distance changes between the PRL and adjacent intraocular structures in the nonaccommodative state (baseline) and during accommodation.

MAIN OUTCOME MEASURES

Mean distance changes from the anterior lens surface (ALS) to the PRL and from the corneal posterior surface to the ALS and the PRL, and changes in the pupil diameter.

RESULTS

At baseline, the mean distances between the PRL and crystalline lens were 0.38, 0.30, and 0.32 mm for the PRL 101, PRL 100, and PRL 200, respectively. The PRLs were significantly closer to the crystalline lens with increasing patient age. Three PRLs were in contact with the crystalline lens (6%), and there were lens opacities in 2 of these eyes. During accommodation, the ALS of all PRL models showed significant forward movement (P<0.05), whereas the distance between the PRL and crystalline lens decreased significantly with the PRL 101 and PRL 200 (P<0.05). The distance between the PRL 100 and crystalline lens remained unchanged during accommodation.

CONCLUSION

The PRL moved forward during accommodation in all eyes, with the distance preserved between the PRL and the ALS with the PRL 100. The distance decreased with the other 2 models. In 85% of cases, there was no mechanical contact with the ALS during accommodation.

[Ultrasound biomicroscopy of posterior chamber phakic intraocular lenses: a comparative study between ICL and PRL models]

PURPOSE

To evaluate the anatomic relationships of the implantable contact lens (ICL) and the phakic refractive lens (PRL) posterior chamber phakic intraocular lenses (PCP IOL) using ultrasound biomicroscopy (UBM).

MATERIAL AND METHODS

Seventeen phakic myopic eyes corrected with ICL, and 14 phakic myopic eyes that had had PRL implantation, were examined retrospectively using UBM. The main parameters measured and compared were anterior chamber depth, central and peripheral distance between PCP IOL and the crystalline lens, and exact lens haptic position.

RESULTS

The mean distance between the PCP IOL and the central endothelium was 2398+/-203 microm and 2640+/-230 microm in the ICL and PRL groups, respectively. The central vault between the implant and the crystalline lens was greater in eyes with ICL (ICL, 402+/-194 microm; PRL, 256+/-187 microm, p<0.05). However, the incidence of lens contact on the peripheral level was higher in the ICL group (41%) than in the PRL group (29%), and the difference between the two implants in the peripheral crystalline lens-PCP IOL distance was significant (p<0.05). Both IOL haptics appeared to be correctly positioned in the sulcus in 13 (76%) eyes of the ICL group, and on the zonule in eight eyes (57%) of the PRL group.

CONCLUSIONS

PCP IOL implantation is a safe procedure for the correction of high myopia with regard to refractive results. UBM provides a unique tool to noninvasively evaluate the relations of these implants within the posterior chamber, and helps to analyze the mechanisms of crystalline lens and iris complications.