Effect of Myopic Defocus on Visual Acuity after Phakic Intraocular Lens Implantation and Wavefront-guided Laser in Situ Keratomileusis.
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ABSTRACT:
SUBMITTER: Kamiya K
PROVIDER: S-EPMC4440037 | biostudies-other | 2015
REPOSITORIES: biostudies-other
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Project description:PurposeThe aim of the study was to determine and compare the relationship between change in simulated keratometry (K) and degree of refractive correction in wavefront-guided (WFG) and wavefront-optimized (WFO) myopic laser-assisted in situ keratomileusis (LASIK).MethodsA total of 51 patients were prospectively randomized to WFG LASIK in one eye and WFO LASIK in the contralateral eye at the Byers Eye Institute, Stanford University. Changes in simulated K and refractive error were determined at 1 year post-operatively. Linear regression was employed to calculate the slope of change in simulated K (ΔK) for change in refractive error (ΔSE). The mean ratio (ΔK/ΔSE) was also calculated.ResultsThe ratio of ΔK to ΔSE was larger for WFG LASIK compared to WFO LASIK when comparing the slope (ΔK/ΔSE) as determined by linear regression (0.85 vs 0.83, p = 0.04). Upon comparing the mean ratio (ΔK/ΔSE), subgroup analysis revealed that ΔK/ΔSE was larger for WFG LASIK for refractive corrections of >3.00 D and >4.00 D (0.89 vs 0.83; p = 0.0323 and 0.88 vs 0.83; p = 0.0466, respectively). Both linear regression and direct comparison of the mean ratio (ΔK/ΔSE) for refractive corrections <4.00 D and >4.00 D revealed no difference in ΔK/ΔSE between smaller and larger refractive corrections.ConclusionWFO LASIK requires a smaller amount of corneal flattening compared to WFG LASIK for a given degree of refractive correction. For both, there was no significant difference in change in corneal curvature for a given degree of refractive error between smaller and larger corrections.
| S-EPMC5880184 | biostudies-literature
Project description:PurposeTo predict clinical defocus curve performance of the PanOptix intraocular lens (IOL) model TFNT00, a population-based image quality metric was applied to a pseudophakic eye model.MethodsVisual acuity (VA) was simulated using a 2-surface reduced eye model. For each virtual eye, the derived corneal surface was combined with scaled IOL surface. Corneal power and aberration, anterior chamber depth, and pupil size were iterated using a Monte-Carlo approach. Image quality of the IOLs was assessed using the total aberration map to compute the amplitude point spread function. A diffraction-normalized light-in-the-bucket metric was calculated for each virtual eye for defocuses from -3.5 D to +1.0 D (step size 0.25 D) and transformed to VAs and defocus curves. Simulated VA for the ReSTOR +3.0 D lens was used to generate a calibration function by linear regression correlation of simulated data with clinical VA data. Simulated TFNT00 VA was then validated by comparing defocus curves to clinical TFNT00 data.ResultsFrom -3.5 D to +1.0 D, the simulated defocus curve was generally consistent with the defocus curve from the TFNT00 clinical trial. The mean absolute difference was 0.022 logMAR (~1 letter) for simulated VA versus clinical trial VA.ConclusionIOL image quality can be assessed using a population-based virtual eye model to simulate VA and predict clinical performance. Computational modeling and simulation can be applied to future IOL development before clinical trials are conducted.
| S-EPMC7782424 | biostudies-literature
Project description:PurposeTo evaluate the accuracy of refractive prediction by the Haigis-L formula compared to four other IOL power calculation formulas in eyes with extremely long axial lengths (AL > 29.0 mm) after LASIK.SettingShanghai Eye Disease and Prevention Treatment Center, Shanghai, China.DesignRetrospective case series.MethodsTwenty-nine eyes from 19 patients were available for analysis. The primary outcome measure was the arithmetic refractive prediction error (RPE), defined as the difference between the actual postoperative refractive error and the intended formula-derived refractive target. The main outcome measure was the median absolute refraction prediction error (MedAE). The accuracy of the Haigis-L was compared with Barrett True K No History, Shammas-PL, SRK/Tcorrected K, and Holladay 2corrected K methods to calculate IOL power.ResultsThe Haigis-L formula had a significantly larger MedAE than Shammas-PL and SRK/Tcorrected K formulas (P = 0.005 and P = 0.015, respectively), a smaller percentage of eyes within ±1.50 diopter (D) of predicted error in refraction compared with Shammas-PL and SRK/Tcorrected K formulas (P = 0.014 and P = 0.005, respectively). The refractive prediction errors of 6 eyes with corneal keratometry of less than 35 D by Haigis-L all had more than 1.95 D of myopic overestimation, while none of the other four methods resulted in an absolute error over 1.95 D.ConclusionsThe Haigis-L formula was relatively accurate in predicting extreme long axis (>29.0 mm) eyes after myopic LASIK surgery but less accurate for eyes with extremely flat corneas (<35 D). SRK/Tcorrected K and Shammas-PL performed better than the other methods for refractive prediction in this type of eyes.SynopsisHaigis-L performed worse than SRK/Tcorrected K and Shammas-PL in predicting IOL power in extremely long axis (>29.0 mm) eyes after myopic LASIK, especially with extremely flat corneas (K < 35 D).
| S-EPMC9151766 | biostudies-literature
Project description:AimTo evaluate the etiology and management of elevated intraocular pressure (IOP) following posterior chamber phakic implantable collamer lens (ICL) surgery.MethodsBetween 2009 and 2015, 638 eyes of 359 subjects with refractive myopia, underwent V4b and V4c (CentraFLOW) model ICL implantation. Ocular hypertension (OHT) was defined as IOP of ≥ 22 mm Hg on two separate occasions and elevated IOP with corresponding optic disc or visual field damage was defined as glaucoma.ResultsElevated IOP ≥ 22 mm Hg was noted in 33 eyes of 30 subjects (33/638; 5.17%). Median age of subjects with raised IOP was 26 years (Inter quartile range (IQR):22, 29) and median refarctive error was -16 diopters (-19.5, -13). The median follow up was 7.8 months (IQR:0.3, 17.6) and median time for postoperative IOP rise was 12 days, (IQR:2, 24). The various etiologies for elevated IOP were steroid response in 21 eyes (64%; 10 eyes with V4b, 11 eyes with V4c), retained viscoelastic in 5 eyes (15%) (3 with V4b, 2 with V4c), pupillary block in four eyes (12%; 3 with V4b, 1 with V4c), malignant glaucoma in one eye (3%, V4b), and missed pre-existing Juvenile open angle glaucoma (JOAG) in two eyes (6% with V4b). Elevated IOP in 31 eyes resolved with conservative management. One eye (centraFLOW design) with central aquaport block by viscoelastic, needed AC wash and one eye with malignant glaucoma needed parsplana vitrectomy and hyaloidotomy. Ten eyes required longterm (>2 months) antiglaucoma medications (AGM) for IOP control. Except the two eyes with JOAG, none had disc and field damage.ConclusionIn our series, OHT was seen in 4.85% and glaucoma in 0.3% eyes that underwent V4b and V4c model ICL implantation. Multiple etiologies were noted and steroid induced ocular hypertension was the most common cause of elevated IOP followed by retained viscoelastic and pupillary block. One third of these eyes required longterm AGM for IOP control.
| S-EPMC5113895 | biostudies-literature
Project description:Purpose:To assess the efficacy and safety of a novel ophthalmic viscosurgical device-free (OVD-free) method for posterior chamber phakic intraocular lens (PIOL) implantation in myopic eyes. Methods:In this retrospective cohort study, the medical records of myopic eyes that underwent PIOL (Implantable Collamer Lens, ICL) implantation for myopia correction at the Eye Hospital of Wenzhou Medical University between May 2015 and March 2017 were reviewed. A total of 49 eyes with complete data that met follow up requirements (2?h, 1?day, 1?week, 3?months postoperatively) were recruited. Based on the surgical techniques used, the eyes were divided into the OVD-free method group and the standard method group. The clinical data, including intraocular pressure (IOP), corrected distance visual acuity (CDVA) and spherical equivalent (SE), at each follow-up were collected for comparison. Endothelial cell loss and complications were also investigated. Results:Twenty-one eyes received the standard method, and 28 eyes received the OVD-free method. A rise in IOP >?22?mmHg at 2?h was noted in 14 eyes (66.7%) in the standard group and none (0%) in the OVD-free group (p?<?0.001). The rise in IOP from baseline was significantly higher at 2?h in the standard group (10.5?±?5.2?mmHg vs. 2.2?±?3.3?mmHg, difference: 8.3, 95% CI 5.8 to 10.8; p <?0.001). There was a significant difference in the time course of LogMAR CDVA changes between the two groups (p?=?0.047). The LogMAR CDVA was significantly better in the OVD-free method group compared to the standard group at 1?day (-?0.076, 95% CI -?0.134 to -?0.018; p?=?0.012), 1?week (-?0.071, 95% CI -?0.135 to -?0.007; p?=?0.03), but not at 3?months (-?0.046, 95% CI -?0.107 to 0.015; p?=?0.134). There was no significant difference in the time course of SE changes between the two groups (p?=?0.471; p?=?0.705). In the OVD-free group, mean endothelial cell loss was 4.6% at 3?months (2522?±?281 vs. 2407?±?226 cells/mm2, difference: -115, 95% CI -?295 to 65; p?=?0.187). No complications were reported in both groups except for the early IOP elevation in the standard group during the observation period. Conclusions:The OVD-free method is safe and efficient for ICL implantation. It can be a safer method of ICL implantation compared to the standard method in that it completely eliminates ophthalmic viscoelastic devices-related complications without causing additional complications.
| S-EPMC7137322 | biostudies-literature
Project description:PurposeTo report the myopic shift at 5 years of age after cataract surgery with intraocular lens (IOL) implantation for infants enrolled in the Infant Aphakia Treatment Study (IATS).MethodsRefractions were performed at 1 month and every 3 months postoperatively until age 4 years and then at ages 4.25, 4.5, and 5 years. The change in refraction over time was estimated by linear mixed model analysis.ResultsIntraocular lens implantation was completed in 56 eyes; 43 were analyzed (median age, 2.4 months; range, 1.0-6.8 months). Exclusions included 11 patients with glaucoma, 1 patient with Stickler syndrome, and 1 patient with an IOL exchange at 8 months postoperatively. The mean rate of change in a myopic direction from 1 month after cataract surgery to age 1.5 years was 0.35 diopters (D)/month (95% confidence interval [CI], 0.29-0.40 D/month); after age 1.5 years, the mean rate of change in a myopic direction was 0.97 D/year (95% CI, 0.66-1.28 D/year). The mean refractive change was 8.97 D (95% CI, 7.25-10.68 D) at age 5 years for children 1 month of age at surgery and 7.22 D (95% CI, 5.54-8.91 D) for children 6 months of age at surgery. The mean refractive error at age 5 years was -2.53 D (95% CI, -4.05 to -1.02).ConclusionsAfter IOL implantation during infancy, the rate of myopic shift occurs most rapidly during the first 1.5 years of life. Myopic shift varies substantially among patients. If the goal is emmetropia at age 5 years, then the immediate postoperative hypermetropic targets should be +10.5 D at 4 to 6 weeks and +8.50 D from 7 weeks to 6 months. However, even using these targets, it is likely that many children will require additional refractive correction given the high variability of refractive outcomes.
| S-EPMC5507620 | biostudies-literature
Project description:To determine deep optic nerve head structure changes after transient intraocular pressure elevation during laser in situ keratomileusis (LASIK) for myopia.Enhanced depth imaging-optical coherence tomography was performed in each myopic eye that underwent LASIK surgery. Enhanced depth imaging-optical coherence tomography images were created at postoperative 1 day, 1 week, 2 weeks, and 1 month. Lamina cribrosa (LC) thickness, LC depth and prelaminar thickness at the superior, middle and inferior portions of the optic nerve head were measured by two investigators.Forty eyes in 40 patients were included in the present study. During follow-up, there were no significant differences in prelaminar thickness or LC depth. The LC demonstrated increased thickness at postoperative 1 day at all three locations (superior, middle, and inferior) (p < 0.001, p < 0.001, p < 0.001, respectively). However, no significant changes were observed at postoperative 1 week, 2 weeks, and 1 month.The LC thickness could increase at 1 day after LASIK surgery. However, the thickness will gradually return to baseline morphology. Temporary intraocular pressure increase during LASIK does not appear to induce irreversible LC thickness changes.
| S-EPMC5906408 | biostudies-literature
Project description:PurposeCompare intraocular pressure (IOP) measured by a standard Goldmann applanation tonometer prism (IOPg) and a modified correcting applanation tonometer surface Goldmann prism (IOPc) before and after laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK).MethodsGoldmann tonometry was analyzed in a retrospective, cross-sectional study, using both GAT and modified-GAT prisms pre-operatively and at the 3 month post-operative appointment on 120 eyes (64 patients) who received LASIK (n = 58) or PRK (n = 62). Demographics, central corneal thickness (CCT), manifest refraction and corneal curvature (CC) data was collected at each visit as well as surgical parameters, including maximum ablation depth.ResultsMean paired IOP following LASIK decreased by - 3.28 ± 3.2 mmHg measured by IOPg and - 1.93 ± 3.3 mmHg by IOPc (p ≤ 0.0001). Mean paired IOP following PRK reduced by - 1.92 ± 3.6 mmHg measured by IOPg and - 1.06 ± 3.6 mmHg by IOPc (p ≤ 0.0001). Increased LASIK ablation depth and post-procedural change in CCT trended toward a statistically significant reduction in IOPg (p = 0.07,p = 0.12), but not IOPc (p = 0.18,p = 0.32). PRK ablation depth was not associated with a reduction in IOPg or IOPc.DiscussionThe modified Goldmann (IOPc) prism measured less of an IOP reduction following LASIK and PRK compared to the standard (IOPg) prism, and the IOP reduction with both prisms was associated with the degree of myopic correction.What is already known and the residual queryCorneal refractive surgery generally demonstrates significant postoperative Goldmann IOP reductions. Presumably, this is due to corneal biomechanical changes for which a newer method of Goldmann IOP measurement may be able to compensate.What this study addsA modified, corneal conforming Goldmann prism demonstrates significantly less IOP reduction following myopic LASIK and PRK compared to the standard flat Goldmann prism.How this study might affect research, practice or policyA newer, modified Goldmann prism may help detect glaucoma and OHT at an earlier stage in patients which have undergone LASIK or PRK. The findings corroborate predicted corneal biomechanical changes following the most common corneal refractive procedures.
| S-EPMC9768993 | biostudies-literature
Project description:Among 20 million cataract surgeries being performed worldwide every year, approximately 5% are being complicated by posterior capsule rent or zonular dialysis. Intraocular lens (IOL) implantation in such cases with intraoperative complications is quite challenging. Our next course of action is to place the IOL in the ciliary sulcus, however, there is a risk of IOL drop into the vitreous in cases of inadequate support. We have described a novel idea of using a suture material through the dialling hole of a three-piece rigid IOL which can be used as a leash to reduce the risk of IOL drop during implantation in such cases. This technique could also be used during sutureless scleral fixated IOL and retro-pupillary iris claw lens implantation. We found that in 90 consecutive patients where this technique was used, there was no incidence of IOL drop or retinal detachment.
| S-EPMC7210857 | biostudies-literature
Project description:The aim was to examine efficacy and safety after Implantable Collamer Lens (ICL) implantation for correction of myopia et myopic astigmatism.This prospective clinical study included 28 eyes of 16 patients which underwent implantation of ICL for correction of myopia up to -18,00 diopters (D) and myopic astigmatism up to -6,00 D in the Eye Clinic Svjetlost Sarajevo, from January 2013 to January 2016. Uncorrected distance visual acuity (UDVA), spherical equivalent (SE), corrected distance visual acuity (CDVA), intraocular pressure (IOP), endothelial cell (EC) density were evaluated at one, six and twelve months. For statistical analysis SPSS for Windows and Microsoft Excel were used.Out of 16 patients, with mean age of 28,21 ± 4,06 years, 12 of them had binocular and 4 of them had monocular procedure. After 12 months mean UDVA was 0,76 ± 0,16 compared to UDVA 0,04 ± 0,03 preoperatively. Mean SE preoperatively was -0,21 ± 0,27 D compared to -9,52 ± 3,69 D preoperatively. At 12 months one eye (3,57%) lost 2 Snellen lines. In this study 8 eyes (28,57%) gained 1 line, 5 eyes gained (17,56%) 2 lines, and 3 eyes (10,72%) gained 3 lines. EC loss was 5,50±4.71% after 12 months. There was no significant change of IOP by the end of 12 months follow up period. One haptic crack was reported as the only intraoperative complication. Three postoperative complications were: two lens rotations and one retinal detachment.Implantation of ICL is an effective and safe method for reducing or correcting myopia and myopic astigmatism.
| S-EPMC5511534 | biostudies-other