Internal Higher-order Aberrations Research Articles

Higher order aberrations according to spherical, and astigmatic refractive errors in children

ABSTRACT Clinical relevance The results of this study present novel insights into the impact of spherical and astigmatic refractive errors on overall, corneal and internal aberrations and may provide a clear understanding of the emmetropisation process and the development of visual function. Background This study aimed to assess the association between overall, corneal and internal higher-order aberrations and the spherical and astigmatic components (magnitude and angle) of refractive error in a large sample of children. Methods A total of 311 children aged 7 – 8 years old were classified based on spherical equivalent refraction (myopic, emmetropic and hyperopic); magnitude of astigmatism (none, low and moderate); and angle of astigmatism (with-the-rule, against-the-rule and oblique). Refractive error and overall, corneal and internal higher-order aberrations were measured using the OPD-Scan III workstation. Results Regarding spherical equivalent refraction, myopic eyes had greater root mean square (RMS) overall higher-order values, total spherical, tetrafoil and secondary astigmatism aberrations, and internal higher-order, total spherical and tetrafoil aberrations in comparison to emmetropic eyes. The magnitude of astigmatism was positively associated with all overall RMS aberrations and with internal higher order, coma, total coma, total spherical and tetrafoil aberrations. Eyes with with-the-rule astigmatism showed higher RMS values of coma and total coma compared to eyes with against-the-rule and oblique astigmatism. Conclusions Higher-order aberrations are dependent on the spherical as well as astigmatic components of refractive error. These findings enhance the current understanding of the emmetropisation process and visual function development.

Современные подходы к хирургии катаракт с высокой остротой зрения на основании анализа волнового фронта

Relevance. Until recently, visual acuity was the main criterion for determining the timing of surgery, but already in the early stages of cataract development, patients may suffer from reduced image quality, which affects the quality of life (“night” myopia, light scattering, blurring). Deterioration in visual function in these patients may be explained by refractive errors. Analysis of internal higher-order aberrations resulting from slight opacification of the lens is important for determining the effect of media opacity on wavefront aberrations (WF) and for determining the indications and timing of surgical treatment, especially in patients with high visual acuity. Purpose. Evaluate the optical system of the eye with initial cataracts and high visual acuity. Evaluate the wavefront and its aberrations, contrast sensitivity and Shtrel coefficient. Material and methods. The study included 111 eyes with cataracts and 42 eyes without signs of cataracts (control group). Patients aged on average 57±5.3 years. Wavefront analysis was performed using an iTrace ray tracing aberrometer (Tracey Tech., USA) in a dark room under maximum drug-induced mydriasis. In each group, total, corneal, and internal wavefront aberrations were measured at a pupil diameter of 6.0 mm. Higher order aberrations were analyzed using Zernike polynomials (3rd to 5th order). The modulation transfer function (MTF) at different spatial frequencies (0–30 c/deg) and the Strehl coefficient in patients in the study groups were also assessed. Results. Total and internal higher-order wavefront aberrations were significant in different cataract groups compared with control patients, while higher-order corneal aberrations were not statistically different. We noted a higher level of total and internal aberrations in the group of patients with posterior subcapsular cataract. In this regard, patients with posterior subcapsular cataract require surgical treatment at an earlier stage, despite high visual acuity. Conclusion. We recommend assessing the optical quality of vision and wavefront aberrations when observing early cataracts in order to decide whether to perform surgery at an earlier date. Key words: initial cataract, quality of vision, higher order aberrations, internal wavefront aberrations

Intraindividual Comparison of an Enhanced Monofocal and an Aspheric Monofocal Intraocular Lens of the Same Platform

To compare intraindividual differences in visual performance of a monofocal and enhanced monofocal intraocular lens (IOL) of the same platform. Prospective, interventional, fellow-eye comparison clinical study. In total, 55 patients (110 eyes) with bilateral age-related cataract were enrolled. All patients received a monofocal ZCB00 IOL in the dominant and an enhanced monofocal Eyhance ICB00 IOL in the nondominant eye. After 2 to 4 months, monocular best-corrected distant visual acuity (BCDVA), distance-corrected intermediate visual acuity (DCIVA), distance-corrected near visual acuity (DCNVA), contrast visual acuity, monocular defocus curves, internal higher-order aberrations (HOAs) and spherical aberrations (SA), decentration, and tilt were compared. The monocular mean BCDVA, DCIVA at 80 cm and 66 cm, and DCNVA were -0.03 ± 0.07, 0.24 ± 0.12, 0.32 ± 0.13, and 0.50 ± 0.13 logarithm of the minimum angle of resolution for the enhanced ICB00 and -0.06 ± 0.06 (P = .014), 0.30 ± 0.11 (P = .005), 0.38 ± 0.12 (P = .004), and 0.55 ± 0.14 (P = .034) logarithm of the minimum angle of resolution for the ZCB00, respectively. Internal HOAs (P = .001) and negative SA (P < .001) were increased with the ICB00 at 3 mm and comparable at 5 mm (P > .05). Contrast acuity, tilt, and decentration were similar (P > .05). Significantly increased monocular DCIVA at 80 cm and 66 cm and DCNVA at 40 cm were observed with the enhanced ICB00 IOL, and the ZCB00 IOL demonstrated better BCDVA. This would result in a mean gain of 2 to 3 Early Treatment of Diabetic Retinopathy Study letters at near and intermediate distance. Monocular defocus curves displayed highest differences of 5 Early Treatment of Diabetic Retinopathy Study letters at -1.25 diopters (D) and -1.50 D levels of defocus and a depth of focus of 1.23 D for the ICB00 IOL and 0.94 D for the ZCB00 IOL. Decentration, tilt, and HOAs were generally low.

Analysis of the relationship between lens morphology and aberrations in patients with myopia: a cross-sectional study.

To investigate the relationship between lens morphology and aberrations in patients with myopia. This cross-sectional study included 155 patients with myopia in their right eyes. Spherical power and cylindrical power were achieved by cycloplegic autorefraction. The eyes were divided into three groups for analysis based on their spherical equivalent (SE) values. The 4mm and 6mm ocular and internal aberrations were measured using the OPD-scan III. Lens parameters were measured using CASIA2, including lens thickness (LT), radius of anterior/posterior lens surface curvature (RAL/RPL), lens decentration (DEC), and lens tilt (TILT). The differences of lenticular parameters and aberration parameters among the three groups analyzed with ANOVA or Kruskal Wallis test. Pearson correlation or Spearman correlation analysis was performed to evaluate the relationships between the lens parameters and aberrations. A p value < 0.05 indicated statistical significance. The difference in LT, RAL, DEC and TITL among the three groups was statistically significant (p < 0.05). And there were differences among differences in internal high-order aberrations, spherical aberration, and coma aberration(p < 0.05).Spherical power was positively correlated with LT and TITL (p < 0.05) and negatively correlated with DEC, RAL, and RPL (p < 0.05). Cylindrical power was positively correlated with LT (p < 0.05) and negatively correlated DEC (p < 0.05); The lenticular parameters (LT, RAL, DEC, and TILT) were mainly correlated with the ocular and internal spherical aberration. LT and DEC were correlated with ocular and internal higher-order aberrations and comaaberration. DEC and LT were the main factors affecting aberrations in patients with myopia.

Higher order aberrations and visual function in a young Asian population of high myopes

PurposeTo examine the associations between higher order aberrations (HOAs), visual performance, demographics, and ocular characteristics in a young Asian population with high myopia. MethodsThis was a retrospective review of military pre-enlistees conducted between March 2014 to September 2018. Visual acuity and contrast sensitivity were tested under photopic, mesopic and simulated night conditions. Ocular, corneal and internal HOAs were measured with a Hartmann–Shack wavefront aberrometer (KR-1W, Topcon Co., Tokyo, Japan). Results522 eyes of 263 consecutive subjects with severe high myopia (defined as spherical equivalent refraction [SER] ≤ −10.00D) in at least one eye, and high myopia (SER ≤ −6.00D) in the fellow eye, [mean (SD) SER −11.85 (2.03D)] were analysed. The mean (SD) age of subjects was 18.5 (1.6) years. Chinese eyes had significantly greater internal total HOA root-mean-square (RMS) compared to Malay eyes [mean difference (SD) 0.0246 (0.007) μm, p < 0.001). More negative SER was associated with greater ocular total HOA (p = 0.038), primary coma (p = 0.003) and tetrafoil (p = 0.025) RMS, as well as more positive ocular (p = 0.003) and internal primary spherical aberration (p = 0.009). Greater ocular total HOAs was associated with reduced visual acuity in simulated night conditions and low contrast, decreased contrast sensitivity under mesopic and simulated night conditions (all p < 0.05). ConclusionsGreater HOAs were associated with Chinese ethnicity and more negative SER in a young Asian population with high myopia. Greater HOAs were associated with poorer visual performance in low luminance and reduced contrast conditions.

Intraocular Lens Tilt and Decentration after Cataract Surgery with and without Primary Posterior Continuous Curvilinear Capsulorrhexis.

To evaluate intraocular lens (IOL) tilt and decentration and their effects on high-order aberrations (HOAs) after cataract surgery with and without primary posterior continuous curvilinear capsulorrhexis (PPCCC). Fujian Provincial Hospital, Fujian, China. Prospective, intraindividual, randomized, comparative clinical trial. This study enrolled 64 eyes of 32 patients with age-related cataract who underwent bilateral cataract surgery and IOL implantation. In randomized order, all patients had phacoemulsification cataract surgery with PPCCC in one eye (PPCCC group) and routine cataract surgery in the contralateral eye (NPCCC group). IOL decentration, tilt, HOAs, modulation transfer function, and point spread function were measured at 1 day, 1 week, 1 month, and 3 months after surgery using OPD-Scan III. 52 eyes of 26 patients were available for analysis. The mean overall decentration in NPCCC group was significantly higher than in PPCCC group at 3 months (0.302±0.157 mm vs 0.187±0.099 mm, P<0.001). Under 3-mm pupil, internal spherical aberration (SA) 1 day after surgery, and coma 1 week after surgery were lower in PPCCC group compared with NPCCC group (0.15±0.10 μm vs 0.30±0.21 μm, P<0.001, and 0.34±0.18 μm vs 0.47±0.31 μm, P=0.03, respectively). IOL decentration was significantly correlated with ocular and internal coma, ocular and internal SA, and internal HOAs at 5-mm pupil (R=0.083 and R=0.099, R=0.650 and R=0.613, R=0.418, respectively, all P<0.01). Less IOL decentration was observed in PPCCC group at 3 months after surgery, indicating that PPCCC may result in better IOL centrality.

A comparative study of transscleral sutured intraocular lens fixation and sutureless flanged intraocular lens fixation

BackgroundTo compare the intraocular lens (IOL) tilt and decentration and visual outcomes of transscleral sutured IOL fixation and sutureless flanged IOL fixation. To investigate the influence of IOL tilt and decentration on internal higher-order aberrations (HOAs) in these two techniques.MethodsPatients who received transscleral sutured or sutureless flanged IOL fixation procedures were included in this prospective, non-randomized, comparative study. Corrected distance visual acuity (CDVA) was measured at baseline and at every postoperative visit for 12 months. IOL tilt and decentration were measured using a second-generation anterior segment optical coherence tomography (Casia2) and internal HOAs were measured using iTrace Visual Function Analyzer at 3 months postoperatively.ResultsThe study included 27 eyes from the transscleral sutured IOL fixation group and 26 eyes from the sutureless flanged IOL fixation group. There was no significant difference in CDVA between the two groups at all time points. The two groups did not differ in refractive difference from the predicted value, corneal endothelial cell loss, IOL tilt, IOL decentration, internal astigmatism or internal HOAs. Vertical IOL decentration significantly correlated with total internal optical aberration (r = 0.288, P = 0.036), total internal HOA (r = 0.440, P = 0.001), internal coma (r = 0.348, P = 0.001), vertical internal coma (r = 0.388, P = 0.004), average height of modulation transfer function (r = − 0.364, P = 0.007) and Strehl ratio (r = − 0.297, P = 0.031). Horizontal IOL decentration significantly correlated with horizontal internal coma (r = 0.312, P = 0.023).ConclusionsTransscleral sutured IOL fixation and sutureless flanged IOL fixation had similar IOL positions and visual outcomes. IOL decentrations correlated with internal HOAs and thus should be avoided.

Short-term clinic observation of misalignment and rotational stability after implantable collamer lens implantation.

We aimed to investigate misalignment (tilt and decentration) and rotational stability of the implantable collamer lens V4c 6months after implantation and to explore the potential risk factors associated with postoperative misalignment and rotation. A total of 36 eyes of 36 patients with high myopia and myopic astigmatism who underwent implantable collamer lens V4c implantation were included in this study. Tilt, decentration, and rotation of the implantable collamer lens were assessed postoperatively at l week, 1month, 3months, and 6months. Correlation analysis was used to identify the potential risk factors for implantable collamer lens tilt, decentration, and rotation at 6months postoperatively. Higher-order aberration was measured to evaluate the effect of implantable collamer lens misalignment on visual quality at pupil diameters of 4.0mm and 6.0mm. The tilt and decentration at the last follow-up were 2.43 ± 1.35° and 0.278 ± 0.160mm, respectively. There was a significant positive correlation between tilt and decentration (r = 0.31, P = 0.046). No significant correlation was detected between implantable collamer lens decentration and internal higher-order aberrations (P > 0.05). The degree of implantable collamer lens rotation (3.11 ± 2.00°) was significantly associated with the vault (r = - 0.422, P = 0.01), while it was positively associated with the preoperative anterior chamber depth (r = 0.36, P = 0.034). No significant correlation was found between postoperative astigmatism and rotation (r = - 0.07, P = 0.351). The implantable collamer lens V4c provides relatively stable misalignment and rotation after implantation. The ICL lens vault is a potential risk factor for postoperative implantable collamer lens rotation. The absolute value of decentration and tilt was relatively small, which showed no correlation with internal higher-order aberration in short-term observation.

Influence of decentration and tilt of Tecnis ZCB00 on visual acuity and higher order aberrations.

To determine the influence of decentration and tilt of a pseudophakic aspheric intraocular lens (IOL) on visual acuity (VA) and higher-order aberrations (HOAs), and to analyze the agreement between pupil center/axis and iridocorneal angles center/axis when assessing IOL decentration and tilt. A prospective interventional case series study including thirty-three patients undergoing Tecnis ZCB00 (Abbott Medical Optics) implantation. IOL decentration and tilt with respect to two reference systems (pupil and iridocorneal angles centers/axes), in cartesian (X,Y) and polar (radius/tilt, polar angle/azimuth) coordinates, were assessed with optical coherence tomography. VA and internal and ocular HOAs were evaluated. Multiple linear regression models and intraclass correlation coefficient (ICC) were computed. IOL decentration only showed a significant effect on internal HOAs for [Formula: see text] (R2 = 0.20, P = 0.04). IOL decentration with respect to the pupil center showed a significant effect on ocular [Formula: see text] (R2 = 0.18, P = 0.05), [Formula: see text] (R2 = 0.36, P = 0.001) and [Formula: see text] (R2 = 0.24, P = 0.02); and with respect to the center of iridocorneal angles, on ocular [Formula: see text] (R2 = 0.21, P = 0.03), [Formula: see text] (R2 = 0.32, P = 0.003), primary coma (R2 = 0.41, P < 0.001), and coma-like (R2 = 0.40, P = 0.001). Poor agreement between both reference systems was found for IOL decentration measurements (ICC ≤ 0.41), except for the polar angle coordinate (ICC = 0.83). Tilt measurements showed good agreement (ICC ≥ 0.75). Tecnis ZCB00 decentration and tilt values after uneventful implantation appear not to have influence on VA, and their effect on HOAs are not high enough to clinically affect quality of vision. Pupil and iridocorneal angles used as reference systems may be interchangeable for IOL tilt measurements, but not for decentration.

Visual outcome and optical quality of a wavefront-engineered extended depth-of-focus intraocular lens.

To evaluate visual performance and optical quality of an extended depth-of-focus intraocular lens (EDoF IOL) compared with a monofocal aspheric IOL. Department of Ophthalmology, Charité-Medical University Berlin, Germany. Prospective case series. After phacoemulsification, a total of 28 patients (56 eyes) underwent bilateral implantation of either the Mini Well (EDoF IOL) or the Mini 4 (monofocal IOL). Assessments including refraction, distance, intermediate and near visual acuity, defocus curves, contrast sensitivity, glare disability, higher-order aberrations (HOAs), and patient satisfaction were performed at 1 month and 3 months postoperatively. Both study groups comprised 14 patients (28 eyes) each. At 3-month follow-up, the EDoF IOL showed better results in monocular uncorrected intermediate visual acuity (-0.04 vs 0.10 logMAR, P = .000) and in uncorrected near visual acuity (0.13 vs 0.36 logMAR, P = .000), whereas no statistically significant difference was found between groups in monocular uncorrected distance visual acuity (0.04 vs 0.00 logMAR, P = .110). The monocular depth of focus was 0.8 D greater in the Mini Well IOL group. Measurements of internal HOAs revealed a greater negative primary spherical aberration in the EDoF group at pupil sizes of 2.0 to 5.0 mm. At 5.0 mm, total internal HOAs did not differ statistically significantly (0.376 vs 0.340 μm root mean square, P = .068). The Mini Well IOL provided greater depth of focus with superior outcomes at intermediate and near distances and comparable outcomes at far distance. Although inducing higher amounts of spherical aberration, it showed good results under low lighting conditions with little subjective dysphotopsia.

Correlation between ocular refraction and total, corneal, and internal higher-order aberrations in myopic with-the-rule astigmatism

Correlation between ocular refraction and total, corneal, and internal higher-order aberrations in myopic with-the-rule astigmatism

Impact of asteroid hyalosis on internal higher-order aberrations in eyes with cataract accompanied by acoustic shadows on swept-source optical coherence tomography examination.

Increased internal higher-order aberrations (HOAs) have been reported in eyes with asteroid hyalosis, which is usually asymptomatic. This report describes 2 patients with cataract and concurrent asteroid hyalosis. In the first case, internal HOAs were within the normal range, and swept-source optical coherence tomography (SS-OCT) did not show acoustic shadows. After cataract surgery, visual acuity improved and internal HOAs remained within normal limits. However, in the second case, SS-OCT revealed multiple acoustic shadows, presumably due to asteroid hyalosis, and internal HOAs increased in both eyes. After combined vitrectomy and cataract surgery, visual acuity and the internal HOA values improved in both eyes, and acoustic shadows disappeared on SS-OCT. Phacovitrectomy should be considered if the cause of visual impairment is cataract and asteroid hyalosis. Objective assessment of internal HOAs by a wavefront sensor and checking for acoustic shadows on SS-OCT might be useful in detecting this combination of ophthalmic conditions.

The Influence of Decentration on Higher-Order Aberrations in Artisan Aphakic Intraocular Lens Implantation Eyes.

Purpose To characterize the influence of decentration on higher-order aberrations of Artisan aphakic intraocular lens implantation eyes. Setting. Department of Ophthalmology and Vision Science, Eye and ENT Hospital of Fudan University, Shanghai, China. Design Retrospective case series. Methods Twenty-three eyes of 18 patients were retrospectively examined. Location of the IOL was imaged using a slit-lamp, and decentration (the distance from the center of a pupil to the geometric center of the IOL) was measured using the AutoCAD 2007 software. Ocular and internal higher-order aberrations were measured using the wavefront analyzer KR-1W (Topcon) and their correlation with decentration were analyzed. Coma, spherical, 3rd-, 4th-order, trefoil, tetrafoil aberrations, ocular, and internal higher-order aberrations were calculated for a 4.0 mm pupil diameter. Results The mean age of patients was 33.6 ± 21.4 years (ranging from 7 to 72 years). The mean follow-up period was 28.2 ± 10.5 months (ranging from 12 to 52 months). The mean postoperative best-corrected visual acuity (BCVA) was 0.19 ± 0.19 logMAR (range −0.18–0.52). The mean decentration was 0.57 ± 0.28 mm (range 0.15–1.21 mm). There was no correlation between Artisan IOL decentration and ocular higher-order aberrations, internal higher-order aberrations, coma, spherical, 3rd-, 4th-order, trefoil, and tetrafoil aberrations, respectively. There was a positive correlation between Artisan IOL decentration and 2nd-astig aberrations when 2nd-astig aberrations were less than 0.1. Conclusions The position of Artisan IOLs showed slight decentration and the amounts of decentration were not large enough to influence higher-order aberrations.

The effects of implantable collamer lens implantation on higher order aberrations.

To evaluate the changes in higher order aberrations (HOAs) after implantable collamer lens (ICL; Staar Surgical, Nidau, Switzerland) implantation. 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 iTrace (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. 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 (tHOAs), spherical aberration, coma and trefoil as entire, corneal and internal components. The differences in entire tHOAs and in internal tHOAs 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. The ICL implantation corrects the refractive error successfully and changes entire and internal HOAs of the eye.

Comparative Analysis of Clinical and Functional Results and Position of Intraocular Lens after Femtolaser-Assisted and Standard Cataract Phacoemulsification

Modern surgical treatment of cataracts provides effective results. The study of the position of the intraocular lens (IOL) in the capsule bag can be considered as one of the most important factors influencing the final visual and refractive result of the operation.Aim: comparative analysis of clinical and functional results and position of the IOL in the capsular bag, namely decentration and tilt, when performing femtolazer-assisted phacoemulsification (FLACS) and standard phacoemulsification (CPCS). Materials and methods. We surveyed 57 patients (57 eyes). FLACS was performed in 27 patients, CPCS – in 30 patients. Standard methods of research were used, determination of the position of the IOL (decentration and tilt) in the capsular bag on the device OCT-Casia2 (TOMEY, Germany) and study of wave front were conducted.Results. Comparative analysis of the obtained results showed no significant difference between groups in postoperative visual acuity, however, there was the trend towards higher performance corrected distance visual acuity and uncorrected distance in the group FLACS (0.68 ± 0.18 and 0.74 ± 0.2) compared to the group CPCS (0.58 ± 0.28 and 0.65 ± 0.24). Internal higher order aberrations were significantly low in the group with femtolazer accompaniment: in 3 mm zone almost 2 times (p = 0.041), in 5 mm zone 1.3 times (p = 0.047). Vertical decentration in a CPCS group made 0.217 ± 0.26 mm, in FLACS group – 0.118 ± 0.05 mm, the vertical tilt – 0.75 ± 0.37° and 0.54 ± 0.36 respectively. Conclusion. Decentralizations and IOL tilt tended to lower indices in the FLACS during the observation period up to 2 months after the operation, which was accompanied by lower values of higher order internal aberrations.

Precision and agreement of higher order aberrations measured with ray tracing and Hartmann-Shack aberrometers

BackgroundTo assess the precision and agreement of measurements of higher order aberrations (HOAs) obtained with a ray tracing aberrometer (iTrace) and a Hartmann-Shack aberrometer (Topcon KR-1 W).MethodsProspective evaluation of the diagnostic test. Data from the right eyes of 92 normal subjects obtained using the two devices were included in this study. Two observers performed 3 consecutive scans to determine the intraobserver repeatability and interobserver reproducibility. About one week later, one observer performed an additional 3 consecutive scans to obtain the intersession reproducibility. The within-subject standard deviation (Sw), test-retest repeatability (TRT) and intraclass correlation coefficient (ICC) were used to assess the precision, while Bland-Altman plots were performed to assess the agreement.ResultsFor intraobserver repeatability of the ocular, corneal and internal HOAs, Topcon KR-1 W showed a 2.77Sw of 0.079 μm or less and ICCs of 0.761 or more; and iTrace showed a 2.77Sw of 0.105 μm or less and ICCs of 0.805 or more. The ICCs of the internal HOAs of interobserver reproducibility were less than 0.75 except for spherical aberration (SA) (0.862), and interobserver reproducibility of the counterpart showed similar but lower results. For the ocular, corneal and internal HOA measurements, statistically significant differences existed between the Topcon KR-1 W and iTrace (all P < 0.05). No significant differences were observed in the ocular SA and internal coma.ConclusionsThe ray tracing and Hartmann-Shack method aberrometers provided excellent repeatability but less reliable reproducibility in the measurement of HOAs (except for SA). The two aberrometers should not be interchangeable in clinical application because of the significant differences in HOA measurements between them.

Femtosecond laser-assisted cataract surgery and conventional phacoemulsification cataract surgery in patients with lens subluxation

To analyze the results of femtosecond laser-assisted cataract surgery (FLACS) and conventional phacoemulsification cataract surgery (CPCS) in patients with 1-2 degree lens subluxation. The follow-up involved 86 patients (89 eyes). The 1st group comprised 34 patients (35 eyes) that underwent FLACS; the 2nd group included 52 patients (54 eyes) who underwent CPCS. At day four of the follow-up central corneal thickness was significantly lower after FLACS (pm-u=0.024), but the difference did not remain statistically reliable by 1.5 months after the surgery. At discharge day and 4 months after the surgery uncorrected visual acuity (UCVA) after FLACS reliably exceeded UCVA of the 2nd group patients (pm-u=0.00) with mean UCVA being 0.61±0.29 and 0.42±0.25 respectively. Internal higher order aberrations (HOA) in 5.0 mm zone in the 1st group decreased by 4 times and amounted to 0.236±0.06 μm, in the 2nd group increased by 4.1 times and was 4.606±8.16 μm; the difference between the groups was statistically significant (pm-u<0.001). Mean endothelial cells density after FLACS was 2551.91±321.55 cells/mm2, after CPCS - 2352.35±436.68 cells/mm2 (pm-u<0.005). Complications after FLACS included 2 cases (5.71%) of posterior capsular rupture and 1 case (2.8%) of post-op corneal edema; patients after CPCS had 6 (11.1%) and 12 (22.2%) complication cases respectively. FLACS is the safer and more effective surgery choice for patients with 1-2 degree lens subluxation in comparison with CPCS; it decreases the risk of possible complications and provides faster postoperative rehabilitation.

Ocular, corneal, and internal aberrations in eyes with keratoconus, forme fruste keratoconus, and healthy eyes.

The purpose of this study is to evaluate ocular, corneal, and internal aberration parameters in eyes with keratoconus (KC), forme fruste keratoconus (FFKC), and normal eyes. In a prospective study, one eye of 110 patients with KC, 60 FFKC patients, and 150 healthy participants was evaluated using OPD-Scan II. Ocular, corneal, and internal higher-order aberrations were measured through a sixth-order Zernike polynomial decomposition. Receiver operating characteristic analysis was performed to evaluate the diagnostic ability of the aberration parameters in discriminating KC and FFKC from normal eyes. The root mean square of the all ocular aberration measurements was significantly higher in the KC and FFKC patients than that of normal participants (p<0.05). All of the corneal aberration measurements were significantly higher in KC patients than those of normal patients (p<0.05); however, only corneal total higher-order aberration (HOA), vertical and total coma, and higher-order astigmatism were significantly higher in the FFKC patients than normal participants (p<0.05). The results also showed that internal aberration lower-order astigmatism, total trefoil, and total higher-order spherical aberration were significantly different between KC and normal groups (p<0.05). In comparison, internal total HOA, lower and higher-order astigmatism, total trefoil, and vertical coma were significantly different between FFKC and normal groups (p<0.05). Ocular vertical and total coma had the highest ability in discriminating keratoconic from normal eyes. Ocular total higher aberration and total coma had the highest diagnostic ability in discriminating FFKC from normal eyes. The diagnostic ability of internal aberration, on the other hand, was moderate to poor in discriminating KC and FFKC from normal eyes. Ocular aberration especially vertical and total coma and total HOA were found to be suitable parameters to discriminate KC and FFKC from normal patients. These two parameters could be used as discriminating factors in evaluating the patient for refractive surgery in an attempt to avoid iatrogenic ectasia.

Tilt, Decentration, and Internal Higher-Order Aberrations of Sutured Posterior-Chamber Intraocular Lenses in Patients with Open Globe Injuries

Purpose To evaluate the tilt, decentration, and internal higher-order aberrations (HOAs) of sutured posterior-chamber intraocular lenses (IOLs) in patients with open globe injuries. Methods 46 consecutive patients (47 eyes) who underwent transsclerally sutured IOL implantation were enrolled in this prospective cohort study. Nineteen eyes had a history of open globe injury. The tilt and decentration of the IOLs and the visual quality were measured 1 month after surgery. Results The horizontal tilt and decentration of the IOLs in the open-globe-injury group were significantly higher than those in the control group (both P < 0.05). In the open-globe-injury group, the horizontal decentration was significantly greater in the limbus-sclera-involved group (n = 11) than in the only-cornea-involved group (n = 8, P = 0.040). The internal coma, 3rd-order, and total HOA values at pupil sizes of 4 mm (P = 0.006) and 6 mm (P = 0.013) were significantly higher in the open-globe-injury group than in the controls. Consequently, the optical quality data for the modulation transfer function and the Strehl ratio (all P < 0.05) were significantly poorer in the open-globe-injury group. Conclusions Open globe injuries damage the structural integrity of the eyeball, resulting in more-misaligned sutured IOLs and poorer visual quality.

Scheimpflug lens densitometry and ocular wavefront aberrations in patients with mild nuclear cataract

To test correlations between Scheimpflug optical densitometry and ocular higher-order aberrations (HOAs) in patients with mild nuclear cataract. Cornea and Refractive Surgery Department, Hospital de Braga, Braga, Portugal. Retrospective single-center study. In eyes with mild nuclear cataract, lens densitometry was evaluated by Scheimpflug imaging(Pentacam HR), which provided an objective quantification (mean density and maximum density) and grading (nuclear staging score) of the crystalline lens. A visual function analyzer thatcombines ray-tracing aberrometry and Placido disk-based topography (iTrace) was used toevaluate the total ocular and internal HOAs. The study comprised 40 eyes of 30 patients. The mean density of the lens nucleus was 8.99%±0.76% (SD) (range 7.5% to 10.8%), and the mean maximum density was 27.96%±6.97% (range 16.9% to 56.1%). Regarding the score of nuclear staging of the Scheimpflug device, 28 eyes had level 0 and 12 eyes had level 1. Significant positive correlations were found between the mean density and maximum density parameters and the internal HOAs (ρ=0.661, P<.001 and ρ=0.570, P<.001, respectively). There were significant correlations between the quantification parameters derived from Scheimpflug lens densitometry and ocular HOAs. The integration of these technologies can help in clinical decision making and in understanding the subjective symptoms of patients with mild nuclear cataracts. Dr. Ambrósio is a consultant to Oculus Optikgeräte GmbH, Alcon Surgical, Inc., and Carl Zeiss Meditec AG. None of the other authors has a financial or proprietary interest in any material or method mentioned.