Early clinical outcome with lens position adjustment following implantable collamer lens surgery

AIM:To observe early clinical outcome with lens position adjustment following the implantable collamer lens(ICL)surgery.METHODS:Sixty patients were selected for this retrospective study.One eye from each patient received Toric ICL for astigmatism correction,and the other received non-astigmatic ICL surgery using horizontal position.Patients with higher postoperative arch height were selected,and their non-astigmatic eye clinical outcome were observed after ICL surgery at 1wk,1,and 3mo.The clinical measurements included uncorrected visual acuity(UCVA),intraocular pressure(IOP),refractive state,corneal endothelium cell count,and arch height.Three months later,the ICL in each patient’s non-astigmatic eye was adjusted to the vertical from the horizontal position.The results were compared before and 1wk,1,and 3mo after adjustment.RESULTS:UCVA and IOP were significantly reduced 1wk after position adjustment compared to 1wk after ICL implantation(P<0.05).The patients demonstrated significantly reduced arch height and corneal endothelium cell count 1wk,1,and 3mo after adjusting position compared to 1wk,1,and 3mo after ICL implantation(P<0.05).However,there was no significant difference in refraction between 1wk,1,and 3mo after ICL implantation and position adjustment(P>0.05).CONCLUSION:Early positioning adjustment postphakic ICL implantation can benefit patients with adjusted arch height or higher IOP.Despite the good clinical effects,the doctors should pay attention to the potential for adverse effects on UCVA and corneal endothelium cells following early position adjustment after posterior chamber phakic ICL implantation.

Clinical prediction of insufficient vaults after implantable collamer lens implantation

AIM:To determine the factors related to preoperative ocular characters that are predictive of insufficient vault(<250μm)after implantable collamer lens(ICL V4c;STAAR Surgical)implantation.METHODS:The participants underwent ICL surgery and were divided into the low(<250μm)and normal(250-1000μm)vault groups based on the postoperative vault at 3mo.The preoperative biometric parameters and clinical outcomes were compared between the two groups.The relationship between the 3-month vault values and preoperative ocular parameters were evaluated by Generalized estimating equations.RESULTS:Sixteen(23 eyes)and 36 patients(63 eyes)were in the low and normal vault groups,respectively.All implantation procedures were uneventful with no cataract formation in the early postoperative period.The sulcusto-sulcus lens rise(STSL)and iris ciliary angle(ICA)were correlated with vault at 3mo after surgery.Every 0.1 mm increase in STSL was associated with 38.9μm decrease in the postoperative 3-month vault.A rise of 1 degree in ICA is associated with a reduction of 4μm in vault.CONCLUSION:Eyes with a narrow ciliary sulcus are associated with a higher rate of low vault after ICL implantation,suggesting a need for adjustments to the ICL size in these patients.Evaluating the characteristics of the ciliary sulcus contributes valuable information to predict low vault after surgery.

Refractive outcomes after V4c Toric collamer lens implantation over 1y of follow-up

AIM:To evaluate refractive outcomes and corneal astigmatism changes after Toric implantable collamer lens with a central port(V4c T-ICL)implantation over 1y of follow-up.METHODS:A retrospective study was performed including 50 eyes of 50 patients that underwent V4c T-ICL implantation.Uncorrected(UDVA)and corrected(CDVA)distance visual acuities,refraction,refractive and corneal astigmatism changes and corneal coupling correction were evaluated preoperatively,1 and 12mo postoperatively.Vector analysis was used for astigmatism changes.Coefficient of adjustment(CAdj)was calculated for corneal coupling analysis.RESULTS:The mean UDVA achieved was 0.03 logMAR at 1mo and remained unchanged throughout the whole follow-up(P=0.193).At the last visit,84%of the eyes achieved a CDVA of 0.00 logMAR or better.Regarding spherical equivalent refraction(SEQ),96%of eyes were ranges of±1.00 D and 84%of them within±0.50 D.Also,94%of eyes had a remaining refractive cylinder within±1.00 D and 78%of them within±0.50 D.Both,SEQ and refractive cylinder,remain stable over the postoperative follow-up(P=1.000 and P=0.660,respectively).In terms of surgically induced astigmatism(SIA),no statistically significant differences were found over the follow-up(P=0.102)and under correction was found with a correction index lower than the unit at each visit.A keratometric astigmatism induced of 0.59±0.53(vector mean:0.26×73º)D was reached at the last visit.No significant changes in terms of corneal astigmatism orientation were reported over post-surgery visits(P=0.129 and P=0.097 at 1 and 12mo respectively).No clinical significance was found for CAdj on with-the-rule astigmatism.No postoperative complications resulting from the surgery were found.CONCLUSION:Refractive outcomes suggest that the V4c T-ICL implantation for correction of myopic astigmatism was satisfactory in terms of effectiveness,safety,and stability during 1y of follow-up.Corneal astigmatism induced by the incision around 0.5 D is achieved according to the remaining refractive cylinder found at one-year post-surgery.Corneal coupling analysis results in no unexpected spherical change.

Rhegmatogenous retinal detachment in highly myopic eyes with implantable collamer lens

AIM:To investigate the clinical characteristics,treatment methods and outcomes of rhegmatogenous retinal detachment(RRD)in highly myopic eyes with implantable collamer lens(ICL).METHODS:High myopia patients who received treatment for nontraumatic RRD after ICL implantation surgery at the Retinal Department of Zhongshan Ophthalmic Center from Jan 2018 to Dec 2022 were reviewed.Comprehensive ophthalmologic examinations including visual acuity measurement and digital fundus photography were performed in each patient.RESULTS:A total of nine RRD eyes from nine patients who received V4c-ICL implantation were included.The mean time from ICL implantation surgery to the diagnosis of RRD was 32.44±22.56mo(range,1-60mo).At the initial visit for RRD,giant retinal tear(GRT),horseshoe tear,simple round hole,and horseshoe tear combined with round hole were detected in 3,3,2,and 1 eye(s),respectively,with maculaoff in eyes.Eight patients received surgical treatment,and one patient was treated by retinal laser photocoagulation alone.The ICL was preserved in 7 eyes.At the last followup,the mean best corrected visual acuity(BCVA)improved significantly from 1.76±1.06 logMAR at presentation to 0.81±1.01 logMAR(P=0.035),and no case of recurrent retinal detachment was found.CONCLUSION:The morphological presentation of retinal breaks is diverse in this study.The ICL can be preserved in most cases during the course of retinal detachment repair surgery in our data,companied with acceptable visual and anatomical outcomes.

Postoperative efficacy,safety,predictability,and visual quality of implantable collamer lens implantation versus small incision lenticule extraction in myopic eyes:a Meta-analysis

AIM:To compare the postoperative efficacy,safety,predictability,and visual quality of implantable collamer lens(ICL)implantation versus small incision lenticule extraction(SMILE)in myopia eyes.METHODS:Pub Med,EMBASE,Web of Science,Cochrane Library and several Chinese databases were searched at May 2021 to select relevant studies in comparison of clinical outcomes between ICL implantation and SMILE for myopia.The primary outcomes were efficacy,safety,and predictability.And the secondary outcomes were postoperative higher-order ocular aberrations(HOAs),modulation transfer function cutoff frequency(MTF),objective scatter index(OSI),contrast sensitivity and a quality of vision(Qo V)questionnaire.RESULTS:A total of 1036 eyes from 10 studies,of which 503 eyes underwent ICL implantation and 533 eyes underwent SMILE,were enrolled in this Meta-analysis.Pooled results revealed that ICL group had a better safety index and post-corrected distance visual acuity(CDVA)(P=0.007,<0.00001,respectively),and a lower percentage of eyes with a postoperative CDVA lost 1 line(P=0.007)than the SMILE group.No significant differences were found in comparison of the other primary outcomes.In the longterm follow-up(>6mo),ICL group had a lower total HOA,coma,and spherical aberration than SMILE group(P=0.003,<0.00001,0.04).Yet higher trefoil was found in ICL group at 6mo after surgery(P=0.003).Additionally,ICL group also had a higher MTF value(P=0.02),and a higher contrast sensitivity score for spatial frequencies of 1.5,6,and 12 cpds(P=0.02,0.005,0.02,respectively).And it also had a lower score of bothersome in Qo V questionnaire than SMILE group(P=0.003).CONCLUSION:ICL implantation and SMILE have similar and comparable outcomes in term of the efficacy and predictability for correcting high myopia.However,ICL group is relatively safer and also has better visual quality in comparison of SMILE group.

Long-term observation on safety and visual quality of implantable collamer lens V4c implantation for myopia correction:a 5-year follow-up

AIM:To elucidate the safety and visual quality of implantable collamer lens with central hole(ICL V4c)implantation for correcting moderate and high myopia for at least 5y.METHODS:This retrospective study was conducted on 58 patients(114 eyes)who were followed up for at least 5y after ICL V4c implantation.The observation was done before and on 1d,1mo,1 and 5y or more after the surgical procedure.The visual acuity,subjective refraction,intraocular pressure,vault,axial length,central hole position,pupil diameter,visual quality,and adverse events were analyzed.The visual quality includes aberration,the modulation transfer function cutoff frequency(MTF cutoff),objective scattering index(OSI),Stroller's ratio(SR),and visual quality questionnaire.RESULTS:The average follow-up period was 69.25±3.80mo(range 60–82mo)and the preoperative spherical equivalent(SE)was-8.66±1.97 D.At 5y after operation,the safety index was 1.01±0.02 and the efficacy index was 0.99±0.42 and SE was-0.65±0.63 D.The 59.6%of the eyes achieved an uncorrected distance visual acuity of 20/20,76.3%of the eyes had SE within±1.0 D at the last visit.The axial length increased by 0.29±0.71 mm 5y after the surgery(t=-3.843,P<0.001).The mean vault at the last follow-up was 510.59±245.61μm.The central hole was on the temporal side in 80 eyes(84.2%).The visual quality questionnaire showed that 98.2%patients were satisfied with the surgical procedure.Adverse events occurred in 4 eyes(3.5%),including the posttraumatic toric ICL rotation(2 eyes),iris incarceration(1 eye),and posttraumatic ICL displacement(1 eye)at the last follow-up.CONCLUSION:Long-term ICL V4c implantation is safe,effective,and stable for correcting moderate and to high myopia,and the visual quality with patients is excellent and satisfactory,but the progression of axial length still needs attention after surgery.

Vault predicting after implantable collamer lens implantation using random forest network based on different features in ultrasound biomicroscopy images

AIM:To analyze ultrasound biomicroscopy(UBM)images using random forest network to find new features to make predictions about vault after implantable collamer lens(ICL)implantation.METHODS:A total of 450 UBM images were collected from the Lixiang Eye Hospital to provide the patient’s preoperative parameters as well as the vault of the ICL after implantation.The vault was set as the prediction target,and the input elements were mainly ciliary sulcus shape parameters,which included 6 angular parameters,2 area parameters,and 2 parameters,distance between ciliary sulci,and anterior chamber height.A random forest regression model was applied to predict the vault,with the number of base estimators(n_estimators)of 2000,the maximum tree depth(max_depth)of 17,the number of tree features(max_features)of Auto,and the random state(random_state)of 40.0.RESULTS:Among the parameters selected in this study,the distance between ciliary sulci had a greater importance proportion,reaching 52%before parameter optimization is performed,and other features had less influence,with an importance proportion of about 5%.The importance of the distance between the ciliary sulci increased to 53% after parameter optimization,and the importance of angle 3 and area 1 increased to 5% and 8%respectively,while the importance of the other parameters remained unchanged,and the distance between the ciliary sulci was considered the most important feature.Other features,although they accounted for a relatively small proportion,also had an impact on the vault prediction.After parameter optimization,the best prediction results were obtained,with a predicted mean value of 763.688μm and an actual mean value of 776.9304μm.The R²was 0.4456 and the root mean square error was 201.5166.CONCLUSION:A study based on UBM images using random forest network can be performed for prediction of the vault after ICL implantation and can provide some reference for ICL size selection.

Comparison of postoperative optical quality according to the degree of decentering of V4c implantable collamer lens

AIM：To evaluate the clinical outcomes of V4 c implantable collamer lens（Hole ICL） implantation with regard to the optical quality assessed according to different degrees of decentering.METHODS：This included 49 eyes that received conventional ICL and 94 eyes that received Hole ICL.The eyes that received Hole ICL were divided into three groups according to the degree of decentering：group 1,central hole within 1 hole diameter（HD） from the pupil center;group 2,central hole within 1 HD to 2 HD;and group 3,central hole within 2 HD to 3 HD.Visual acuity（VA）,intraocular pressure（IOP）,and spherical equivalent（SE） values were assessed at 1wk,1 and 3mo after surgery.The ocular modulation transfer function,Strehl ratio,objective scattering index,and higher order aberrations（HOAs） were measured for 4-mm pupils at 3mo after surgery.RESULTS：There were no significant differences in VA,IOP,and SE among the conventional and Hole ICL groups.With regard to HOAs,values for coma and spherical aberrations showed no differences.The total HOA and trefoil values were significantly higher in group 2 than in group 1（P=0.02,0.03,respectively）.There were no significant differences among groups with regard to other optical quality parameter at 3mo after surgery.CONCLUSION：Our results suggest that Hole ICL implantation provides satisfactory visual quality that is equivalent to that provided by conventional ICL,regardless of the presence of central hole and degree of decentering.

Implantable collamer lens for residual refractive error after corneal refractive surgery

AIM：To assess the safety,efficacy,predictability and stability of implantable collamer lens（ICL） for residual refractive error after corneal refractive surgery.METHODS： This study evaluated 19 eyes of 12 patients who underwent ICL implantation after corneal refractive surgeries.They were followed up for 1y to 5y of uncorrected distance visual acuity（UDVA）,corrected distance visual acuity（CDVA）,manifest refractive error,flat and steep K value,axial length,intraocular pressure,corneal endothelial cell density,adverse events after ICL surgery.RESULTS： The mean follow-up period was 39.05 ±19.22 mo（range,1-5y）.Spherical equivalent refractive error changed from-7.45±3.02 D preoperatively to-0.85±1.10 D 1wk to 1mo after ICL implantation,with the safety and efficacy indices being 1.12 and 1.15,respectively.A total of 52.63% of eyes were within ±0.5 D of the predicted spherical equivalents,73.68% were within ±1.0 D.A trend of mild regression towards myopia with axial elongation after 5y was observed.One eye with mild anterior capsule opacity and retinal detachment 1y after surgery were observed.CONCLUSION： ICL implantation is safe and effective for the correction of residual refractive error after corneal refractive surgeries,especially in moderate to high residual myopia.

A case of hypermature cataract formation following implantation of an implantable collamer lens with an Aquaport

To improve humor circulation the latest V4c Visian implantable collamer lens （ICL） was designed with a0.36-ram Aquapon. This design also eliminates the need to perform peripheral iridectomy before ICL implantation. Several authors reported rates of secondary surgical intervention related to insufficient vault in the presence or absence of cataract formation and excessive vault in the presence or absence of elevated intraocular pressure （IOP） after ICL insertion. Here, we report a case of rapid progression of a cataract to a hypermature state after implantation of an ICL with an Aquaport.

Comparison of choroidal thickness in high myopic eyes after FS-LASIK versus implantable collamer lens implantation with swept-source optical coherence tomography

AIM:To investigate the changes in choroidal thickness(CT)in high myopic eyes after femtosecond laser-assisted in situ keratomileusis(FS-LASIK)surgery or central hole implantable collamer lens(ICL V4c)implantation using swept-source optical coherence tomography(SS-OCT).METHODS:We examined the right eyes of 116 patients with high myopia who were candidates for FS-LASIK surgery and ICL implantation.Sixty eyes underwent ICL V4c implantation and 56 eyes were subjected to FS-LASIK surgery.The CT was measured with SS-OCT.All data were recorded preoperatively and 2 h,1 wk,1 and 3 mo postoperatively.Other demographic information was collected,including age,sex,uncorrected visual acuity(UCVA),best corrected visual acuity(BCVA),spherical equivalent(SE),intraocular pressure(IOP)and axial length(AL).RESULTS:The UCVA improved in both groups and showed no significant differences between groups.There also were no significant differences between the two groups in postoperative BCVA and SE(P=0.581 and 0.203,respectively).The foveal CTs,inner nasal and outer nasal CTs were significantly thicker at 2 h postoperatively in both groups(P<0.05)but returned to baseline levels in 1 wk;after 1 mo,no significant differences were found relative to the preoperative values.At 3 mo in each group,nine regions showed variations in the CT as compared with preoperative thickening,but only the foveal and nasal area CTs preoperative differences were statistically significant(P<0.05).In addition,there was no significant difference in 9 regions of CT between the two groups at all follow-up times(P>0.05).CONCLUSION:The CTs after ICL implantation and FSLASIK surgery are significantly thicker than those before operation,especially in the foveal and nasal areas,but there is no significant difference between the two methods.

Clinical observations of iridociliary cysts and their changes after implantable collamer lens implantation in myopic patients

AIM:To observe the characteristics of iridociliary cysts in myopic patients and evaluate the influences on the position and safety of implantable collamer lens(ICL)after surgery.METHODS:Totally 270 eyes of 135 patients who underwent ICL surgery for the corrections of myopia were included in this study.Preoperative and postoperative morphology of iridociliary cysts were observed in ultrasonic biomicroscopy(UBM)image.RESULTS:A total of 138 iridociliary cysts were found in 88 eyes of 50 patients among 270 eyes of 135 patients before surgery(37%).Twenty-five patients had cysts in one eye(50%)and 25 had cysts in both eyes(50%).The prevalence of iridociliary cysts was negatively correlated with age,but no gender difference(P>0.05).The incidence of iridociliary cysts was much less in eyes with myopia greater than-9.00 D(P<0.05).The diameter of the largest cyst was 1.96 mm and the smallest cyst was 0.24 mm,with a majority within the range of 0.5 to 1.0 mm.Most of the cysts were located in the inferior temporal quadrant.One year after ICL implantation,51 iridociliary cysts(37%)remained unchanged,47 cysts(34%)decreased in size,and 40 cysts(29%)disappeared.Most of cysts that changed after surgery were smaller than 1.0 mm(P<0.05)and located in the nasal and temporal sides around the haptics of implantable lens.All the ICL were in their original position.CONCLUSION:Iridociliary cysts are commonly seen in myopic eyes.The cysts have no impact on the safety of ICL surgery.Some cysts may decrease in size or disappear after ICL implantation.

Comparison of optical quality after implantable collamer lens implantation and wavefront-guided laser in situ keratomileusis

AIM： To compare the optical quality after implantation of implantable collamer lens（ICL） and wavefront-guided laser in situ keratomileusis（WG-LASIK）.METHODS： The study included 40 eyes of 22 patients with myopia who accepted ICL implantation and 40 eyes of 20 patients with myopia who received WG-LASIK. Before surgery and three months after surgery, the objective scattering index（OSI）, the values of modulation transfer function（MTF） cutoff frequency, Strehl ratio, and the Optical Quality Analysis System（OQAS） values（OVs） were accessed. The higher order aberrations（HOAs） data including coma, trefoil, spherical, 2^（nd） astigmatism and tetrafoil were also obtained. For patients with pupil size 〈6 mm, HOAs data were analyzed for 4 mm-pupil diameter. For patients with pupil size ≥6 mm, HOAs data were calculated for 6 mm-pupil diameter. Visual acuity, refraction, pupil size and intraocular pressures were also recorded.RESULTS： In both ICL and WG-LASIK group, significant improvements in visual acuities were found postoperatively, with a significant reduction in spherical equivalent（P〈 0.001）. After the ICL implantation, the OSI decreasedslightly from 2.34±1.92 to 2.24±1.18 with no statistical significance（P=0.62）. While in WG-LASIK group, the OSI significantly increased from 0.68±0.43 preoperatively to 0.91±0.53 postoperatively（Wilcoxon signed ranks test, P=0.000）. None of the mean MTF cutoff frequency, Strehl ratio, OVs showed statistically significant changes in both ICL and WG-LASIK groups. In the ICL group, there were no statistical differences in the total HOAs for either 4 mmpupil or 6 mm-pupil. In the WG-LASIK group, the HOA parameters increased significantly at 4 mm-pupil. The total ocular HOAs, coma, spherical and 2^（nd） astigmatism were 0.12±0.06, 0.06±0.03, 0.00±0.03, 0.02±0.01, respectively. After the operation, these values were increased into 0.16±0.07, 0.08±0.05,-0.04±0.04, 0.03±0.01 respectively（Wilcoxon signed ranks test, all P〈0.05）. At 6 mm-pupil, the induction of total HOAs was not statistically significant in the WG-LASIK group. CONCLUSION： ICL implantation has a less disturbance to optical quality than WG-LASIK. The OQAS is a valuable complementary measurement to the wavefront aberrometers in evaluating the optical quality.

Optical and visual quality comparison of implantable collamer lens and femtosecond laser assisted laser in situ keratomileusis for high myopia correction

AIM:To compare clinical outcomes and refractive stability of implantable collamer lens(ICL)implantation and femtosecond laser assisted laser in situ keratomileusis(FSLASIK)for high myopia correction.METHODS:The Optical Quality Analysis System(OQAS)was used to evaluate clinical outcomes objectively after operation for high myopia correction.We compared the two procedures in terms of 1-year changes in uncorrected distance visual acuity(UDVA),corrected distance visual acuity(CDVA),safety index,efficacy index,spherical equivalent,modulation transfer function(MTF)cutoff frequency,strehl ratio(SR)and objective scatter index(OSI).RESULTS:At 1 y postoperatively,the safety indices were 1.33±0.27 in ICL group,and 1.17±0.24 in FS-LASIK group.39.58%in the ICL group and 27.59%in the FS-LASIK group gained CDVA in 2 lines or better than that in preoperative CDVA.The efficacy indices were 1.28±0.22 in ICL group,and 1.13±0.26 in FS-LASIK group.The changes of spherical equivalent from 1 wk to 1 y postoperatively was-0.12±0.37 D in ICL group,and-0.79±0.58 D in FS-LASIK group(P<0.05).Spherical equivalent within±0.50 D was achieved in 97.92%in ICL group and 68.97%in FS-LASIK group.MTF cutoff frequency were higher with ICL as compared to FSLASIK(P<0.05)at each postoperative follow-up stage;for postoperative 1 mo later,SR was statistically significant difference between two groups(P<0.05);with no statistically significant difference in OSI between two groups(P>0.05)in postoperative 3 mo later.CONCLUSION:ICL implantation and FS-LASIK procedures both provide good safety and predictability in high myopia correction.ICL implantation provides better clinical outcomes and refractive stability than FS-LASIK.

Full-vision maintenance in extra-high myopia from implantable collamer lens to trifocal intraocular lens implantation

Dear Editor,I am Dr.Ye Shen from the Department of Ophthalmology,the First Affiliated Hospital,College of Medicine,Zhejiang University,Hangzhou,China.I write to share my experience of full-vision maintenance in patient with extrahigh myopia from implantable collamer lens （ICL） to trifocal intraocular lens （IOL） implantation.

Indications for exchange or explantation of phakic implantable collamer lens with central port in patients with and without keratoconus

AIM:To evaluate the causes of phakic implantable collamer lens(ICL)exchange/explantation in patients with and without keratoconus(KC)at two tertiary hospitals in Riyadh,Saudi Arabia.METHODS:A retrospective chart review of all patients who underwent ICL(model V4 c with central port)exchange/explantation was performed using the electronic medical record systems.All available preoperative and postoperative data were documented for each patient.RESULTS:Over 7 y,2283 ICL implantation procedures were performed;46 implants(2%)required exchange(21 implants)/explantation(25 implants),of which 14 cases(30.4%)were patients with KC.Indications for ICL exchange/explantation in non-KC group were vault measurement,cataract formation,increased intraocular pressure,inaccurate refraction,and patient dissatisfaction in 22(68.75%),4(12.5%),3(9.37%),2(6.25%),and 1(3.12%)case,respectively.The most common indication for ICL exchange/explantation in the KC group was inaccurate vault sizing in 11 patients(78.57%),inaccurate refraction in 2 patients(14.28%),and patient dissatisfaction postoperatively in 1(7.14%)case.CONCLUSION:ICL implantation results in predictable refractive outcomes over the long term with exchange/explantation rates comparable to previous literature.Improper vault size is the most common cause of ICL exchange/explantation among patients with or without KC.

The effects of implantable collamer lens implantation on higher order aberrations

AIM: To evaluate the changes in higher order aberrations(HOAs) after implantable collamer lens(ICL;Staar Surgical, Nidau, Switzerland) implantation. METHODS: Totally 30 eyes of 18 patients with myopia were included in this study with an average age of 25.77y(min: 21, max: 40). Refraction, uncorrected distance visual acuity(UDVA), corrected distance visual acuity(CDVA), HOAs(entire, corneal and internal) were evaluated preoperatively and three months postoperatively. Ocular aberrations were measured by using iT race(Tracey Technology, Houston, Texas, USA). SPSS(IBM Corp. Released 2013. IBM SPSS Statistics for Windows, Version 22.0. Armonk, NY: IBM Corp) was used for the statistical analysis and the interpretation of the data. P values of less than 0.05 were considered statistically significant. RESULTS: The preoperative mean spherical power was -9.01 D(min:-5.00, max:-13.00) and the mean cylindrical error was -2.40 D(min:-0.50, max:-4.75). The postoperative mean residual spherical power was -0.73 D(min:-0.20, max:-1.75) and the mean cylindrical error was -0.89 D(min:-0.18, max:-2.09). Analyses were made on root mean square(RMS) values of total HOAs(tH OAs), spherical aberration, coma and trefoil as entire, corneal and internal components. The differences in entire t HOAs and in internal t HOAs were significant. There was no significant change found in spherical aberrations. The differences in entire coma and in internal coma were significant. There was no significant change found in corneal coma. With respect to trefoil, the only significant difference was in internal trefoil. CONCLUSION: The ICL implantation corrects the refractive error successfully and changes entire and internal HOAs of the eye.

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.

Dynamic assessment of variations in pupil diameter using swept-source anterior segment optical coherence tomography after phakic collamer lens implantation

Purpose To dynamically assess variations in pupil diameter induced by changes in brightness in myopic eyes implanted with an implantable collamer lens(ICL,STAAR Surgical)with a central port.Methods This prospective,observational single-center case series study comprised 65 eyes from 65 consecutive patients undergoing ICL implant.A modified commercially available swept-source Fourier-domain anterior segment optical coherence tomography(AS-OCT)device was used for imaging and performing dynamic pupillometry under changing light conditions before and after a mean follow-up interval of four months after surgery.Results Preoperative mean pupil size under photopic conditions was 3.38±0.64 mm;after surgery,this increased to 3.48±0.61 mm.Mean pupil size under scotopic light conditions was 5.72±0.79 mm before surgery and 5.84±0.77 mm postoperatively.The differences between preoperative and postoperative pupil diameter in miosis and mydriasis were 0.10±0.44 mm(P=0.078)and 0.12±0.58 mm(P=0.098),respectively.The scotopic pupil exceeded the optic zone of the implanted lens in 39 eyes(60%).The mean central vault value was 412±177μm under maximum miosis and 506±190μm under maximum mydriasis.We found a positive correlation between vault and differences in pupil diameter under all light conditions(P<0.05).Conclusion Dynamic AS-OCT enables a very precise determination of the pupillary diameter in the iris plane.The changes in the pupil diameter under different light conditions after the implantation of an ICL are related to the postoperative vault.

In vivo optical quality of posterior-chamber phakic implantable collamer lenses with a central port

Background: The aim of this review is to summarize the optical quality results in patients following theimplantation of the V4c implantable collamer lens with a central port (ICL, STAAR Surgical Inc.).Main text: A literature search in several databases was carried out to identify those publications, both prospective,retrospective and/or comparative with other refractive surgery procedures, reporting optical outcomes of patientswho were implanted with the V4c ICL model. A total of 17 clinical studies published between 2012 and 2021 wereincluded in this review. A detailed analysis of the available data was performed including number of eyes, follow-upand preoperative spherical equivalent. Specifically, the review focused on several optical parameters includinghigher-order aberrations (HOAs), modulation transfer function (MTF) cut-off frequency and Strehl ratio. This reviewencompassed a total of 817 eyes measured using different optical devices based on Hartmann-Shack, retinal imagequality measurement and ray-tracing technologies at different follow-ups.Conclusions: The outcomes found in this review lead us to conclude that the ICL V4c model provides good opticalquality, by means of different metrics, when implanted.