Influence of ocular biometric factors on the defocus curve in an enlarged depth-of-focus intraocular lens.

BACKGROUND: To assess the influence of biometric measurements on the defocus curve after the implantation of enlarged depth-of-focus (EDoF) intraocular lens (IOL). METHODS: Patients who underwent cataract surgery with bilateral implantation of Tecnis Symfony IOL were enrolled. Preoperatively, axial length (AL), corneal keratometry (K), pupil size and corneal aberrations were measured. 1 month after surgery, distance, intermediate, and near visual acuities (VA) were recorded. At 3 months, monocular and binocular corrected contrast sensitivities under photopic and mesopic lighting conditions were measured with CSV-1000E test. At 6-months, the defocus curve between -5.00 to + 3.00 diopters (D) was assessed in steps of 0.50 D, and NEI-RQL-42 questionnaire was administered. RESULTS: One hundred thirty one eyes of 66 patients were included. Binocular logMAR VA better than 0.1 for intermediate vision was obtained in 90% of patients, whereas only 17.7% obtained that result in near vision. The rate of satisfaction was high (96%) and most of them (85.5%) had no or little difficulties in near vision. The mean amplitude of the defocus curve was 2.35D ± 0.73D, and smaller AL, smaller pupils, younger age, and male sex were associated with wider range of clear vision. CONCLUSIONS: Tecnis Symfony IOL enables functional vision at all distances, but demographic variables and preoperative biometric measurements like AL and pupil size influence the postoperative amplitude of the defocus curve. These parameters could be used to predict the performance of EDoF IOLs.

Bias of near-infrared light in evaluation of patients implanted with multifocal intraocular lenses.

PURPOSE: To compare visual quality between subjective tests and optical devices using near-infrared (NIR) light in patients implanted with monofocal, multifocal and enlarged depth-of-focus (EDoF) intraocular lenses (IOLs). METHODS: Cross-sectional study enrolling patients aged between 55 and 75 (axial length between 22 and 25 mm) bilaterally implanted with Tecnis IOLs (Johnson & Johnson) four months previously: 40 patients (80 eyes) with monofocal ZCB00, 41 patients (82 eyes) with bifocal diffractive ZMB00 and 48 patients (96 eyes) with EDoF Symfony. They were examined using subjective and objective tests. The subjective tests comprised visual acuity (VA) with ETDRS charts, contrast sensitivity (CS) with Pelli-Robson and CSV-1000E tests, and clear vision range (CVR). The objective tests using NIR light were performed with the KR-1 W wavefront analyzer and the OQAS. RESULTS: In the subjective tests, the monofocal group achieved the best outcomes in some of the VA and CS sections, while the bifocal group obtained the worst outcomes in some of the CS sections. In the objective tests, the bifocal group achieved the best results for VA and CS. Discrepancies between pseudoaccommodation range and CVR were found in the bifocal and EDoF groups. CONCLUSIONS: Assessment of visual quality using NIR light implies greater bias for diffractive lenses than for EDoF lenses. This bias may be even greater with devices using longer light wavelengths or Hartmann-Shack technology. The difference in wavelength between NIR and visible light leads to dimming of near-vision focus and magnification of distance focus.

Evaluation of Fixational Behavior throughout Life.

BACKGROUND: To quantify development of gaze stability throughout life during short and long fixational tasks using eye tracking technology. METHODS: Two hundred and fifty-nine participants aged between 5 months and 77 years were recruited along the study. All participants underwent a complete ophthalmological assessment. Fixational behavior during long and short fixational tasks was analyzed using a DIVE (Device for an Integral Visual Examination), a digital test assisted with eye tracking technology. The participants were divided into ten groups according to their age. Group 1, 0-2 years; group 2, 2-5 years; group 3, 5-10 years; group 4, 10-20 years; group 5, 20-30 years; group 6, 30-40 years; group 7, 40-50 years; group 8, 50-60 years; group 9, 60-70 years; and group 10, over 70 years. RESULTS: Gaze stability, assessed by logBCEA (log-transformed bivariate contour ellipse area), improved with age from 5 months to 30 years (1.27 vs. 0.57 deg2 for long fixational task, 0.73 vs. -0.04 deg2 for short fixational task), while fixations tend to be longer (1.95 vs. 2.80 msec for long fixational tasks and 0.80 vs. 1.71 msec for short fixational tasks). All fixational outcomes worsened progressively from the fifth decade of life. Log-transformed bivariate contour ellipse area (0.79, 0.83, 0.91, 1.42 deg2 for long fixational task and 0.01, 0.18, 0.28, 0.44 deg2 for short fixational task, for group 7, 8, 9, and 10 respectively). Stimuli features may influence oculomotor performance, with smaller stimuli providing prolonged fixations. CONCLUSIONS: Fixational behavior can be accurately assessed from 5 months of age using a DIVE. We report normative data of gaze stability and duration of fixations for every age group. Currently available technology may increase the accuracy of our visual assessments at any age.

Optical aberrations in three different intraocular lens designs of a same platform.

PURPOSE: To compare internal optical aberrations between three different intraocular lenses (IOL) of the same Tecnis platform: monofocal ZCB00, multifocal ZMB00, and enlarged depth-of-focus (EDoF) Symfony ZXR00. METHODS: We included in this study 236 eyes of 118 patients who had been bilaterally implanted either with the monofocal, the multifocal, or the EDoF IOL. They were examined with the K1-RW wavefront analyzer (Topcon Medical Systems) 2 months after surgery. Patients with any ocular pathology were excluded from the study. Only high-order aberrations (HOA) of the third and fourth orders of the Zernike polynomials were considered. RESULTS: Forty-three patients (86 eyes) were implanted with the monofocal IOL, 45 patients (90 eyes) with the ZMB00 IOL, and 30 patients (60 eyes) with the EDoF Symfony IOL. Mean age was 62.42 ± 7.38, 63.60 ± 6.01, and 64.74 ± 5.84 years, respectively. Mean axial length was 23.37 ± 1.00, 23.49 ± 1.00, and 23.54 ± 0.73 mm, respectively. For a 6-mm pupil, internal total HOA in the monofocal group was 1.01 ± 1.75 µm; in the bifocal group was 1.35 ± 2.12 µm; and in the Symfony group was 0.72 ± 0.63 µm. No optical aberration differences were found among the three groups (P > 0.05). CONCLUSION: There are no differences regarding internal optical aberrations between these three IOLs when analyzing them with optical aberrometry. Patients' pupil size should be considered for the selection of the most appropriate IOL to be implanted, because despite a same optical platform, every IOL implies a different increase of HOA with larger pupil sizes.

Equivalence of two optical quality metrics to predict the visual acuity of multifocal pseudophakic patients.

This article studies the relationship between two metrics, the area under the modulation transfer function (MTFa) and the energy efficiency (EE), and their ability to predict the visual quality of patients implanted with multifocal intraocular lenses (IOLs). The optical quality of IOLs is assessed in vitro using two metrics, the MTFa and EE. We measured them for three different multifocal IOLs with parabolic phase profile using image formation, through-focus (TF) scanning, three R, G, B wavelengths, and two pupils. We analyzed the correlation between MTFa and EE. In parallel, clinical defocus curves of visual acuity (VA) were measured and averaged from sets of patients implanted with the same IOLs. An excellent linear correlation was found between the MTFa and EE for the considered IOLs, wavelengths and pupils (R2 > 0.9). We computed the polychromatic TF-MTFa, TF-EE, and derived mathematical relationships between each metrics and clinical average VA. MTFa and EE proved to be equivalent metrics to characterize the optical quality of the studied multifocal IOLs and also in terms of clinical VA predictability.

Development of a system based on artificial intelligence to identify visual problems in children: study protocol of the TrackAI project.

INTRODUCTION: Around 70% to 80% of the 19 million visually disabled children in the world are due to a preventable or curable disease, if detected early enough. Vision screening in childhood is an evidence-based and cost-effective way to detect visual disorders. However, current screening programmes face several limitations: training required to perform them efficiently, lack of accurate screening tools and poor collaboration from young children.Some of these limitations can be overcome by new digital tools. Implementing a system based on artificial intelligence systems avoid the challenge of interpreting visual outcomes.The objective of the TrackAI Project is to develop a system to identify children with visual disorders. The system will have two main components: a novel visual test implemented in a digital device, DIVE (Device for an Integral Visual Examination); and artificial intelligence algorithms that will run on a smartphone to analyse automatically the visual data gathered by DIVE. METHODS AND ANALYSIS: This is a multicentre study, with at least five centres located in five geographically diverse study sites participating in the recruitment, covering Europe, USA and Asia.The study will include children aged between 6 months and 14 years, both with normal or abnormal visual development.The project will be divided in two consecutive phases: design and training of an artificial intelligence (AI) algorithm to identify visual problems, and system development and validation. The study protocol will consist of a comprehensive ophthalmological examination, performed by an experienced paediatric ophthalmologist, and an exam of the visual function using a DIVE.For the first part of the study, diagnostic labels will be given to each DIVE exam to train the neural network. For the validation, diagnosis provided by ophthalmologists will be compared with AI system outcomes. ETHICS AND DISSEMINATION: The study will be conducted in accordance with the principles of Good Clinical Practice. This protocol was approved by the Clinical Research Ethics Committee of Aragón, CEICA, on January 2019 (Code PI18/346).Results will be published in peer-reviewed journals and disseminated in scientific meetings. TRIAL REGISTRATION NUMBER: ISRCTN17316993.

Visual acuity of pseudophakic patients predicted from in-vitro measurements of intraocular lenses with different design.

The optical quality of a set of IOLs (modeling set: one monofocal and two bifocals) was assessed through focus by the area under the modulation transfer function (MTFa) metric and related to the visual acuity (VA) defocus curves of pseudophakic patients implanted with said IOLs. A non-linear relationship between the MTFa and clinical VA was obtained with an asymptotic limit found to be the best VA achievable by the patients. Two mathematical fitting functions between clinical VA and MTFa were derived with high correlation coefficients (R2≥0.85). They were applied to the MTFa obtained from a different set of IOLs with advanced designs (trial set: one extended range of vision -ERV-, one trifocal ERV and one trifocal apodized) to predict VA versus defocus of patients implanted with these IOLs. Differences between the calculated VA and the clinical VA for both fitting models were within the standard deviation of the clinical measurements in the range of -3.00 D to 0.00 D defocus, thus proving the suitability of the MTFa metric to predict clinical VA performance of new IOL designs.

Influence of cardiovascular condition on retinal and retinal nerve fiber layer measurements.

OBJECTIVE: To assess changes in the retinal nerve fiber layer (RNFL) and macula in subjects with cardiovascular risk factors or subclinical ischemia. DESIGN: Prospective and observational study. METHODS: A total of 152 healthy men underwent cardiovascular examination, including quantification of subclinical atheroma plaques by artery ultrasound scans, blood analysis, and a complete ophthalmic evaluation, including spectral-domain optical coherence tomography. The variables registered in cardiovascular examination were quantification of classic major risk factors, subclinical atheroma plaques by artery ultrasound scans, and analytical records. The ophthalmic evaluation registered RNFL and macular thickness. RESULTS: Mean subject age was 51.27±3.71 years. The 40 subjects without classic cardiovascular risk factors did not show differences in RNFL and macular thicknesses compared with the 112 subjects with at least one risk factor (except in sector 9 that showed higher thicknesses in subjects with ≥1 risk factor). Comparison between the group of subjects with and without atheroma plaques revealed no differences in RNFL and macular thicknesses. The sub-analysis of subjects with subclinical atheroma plaques in the common carotid artery revealed a significant reduction in central macular thickness in the left eye compared with the right eye (p = 0.016), RNFL in the superior quadrant (p = 0.007), and the 11 o'clock sector (p = 0.020). Comparison between smokers and nonsmokers revealed that smokers had significant thinning of the central macular thickness (p = 0.034), the nasal RNFL quadrant (p = 0.006), and the 3 and 5 o'clock sectors (p = 0.016 and 0.009). CONCLUSIONS: Classic cardiovascular risk factors do not cause RNFL or macular thickness reduction, but tobacco smoking habit reduces nasal RNFL thickness. Subclinical atherosclerosis in the common carotid artery associates a reduction in central macular and nasal RNFL quadrant thicknesses in the left eye compared with the right eye.

Reading and quality of life differences between Tecnis ZCB00 monofocal and Tecnis ZMB00 multifocal intraocular lenses.

PURPOSE: To compare the NEI-RQL-42 quality of life questionnaire and the Radner Vissum reading test outcomes after bilateral cataract surgery with implantation of Tecnis ZCB00 monofocal and Tecnis ZMB00 multifocal intraocular lens (IOL). METHODS: Forty-two eyes of 21 patients who had phacoemulsification were implanted with Tecnis ZCB00 IOL and 82 eyes of 41 patients were implanted with Tecnis ZMB00 IOL. They answered the NEI-RQL-42 questionnaire before cataract surgery and 3 months after it. The Radner Vissum test was performed 3 months after the surgery with optical correction for near vision in patients with monofocal IOL, but without it in patients with multifocal IOL. RESULTS: Regarding the NEI-RQL-42 test, the multifocal group obtained better results in items 2, 7, 8, 11, 13, 31, and 40, and in the following categories: near vision, dependence on correction, and suboptimal correction (p<0.05). The monofocal group only showed better results in item 17. As for the Radner Vissum test, the multifocal group obtained significantly better results in phrases 1, 3, 4, and 5, and in the number of incorrect syllables (p<0.05). CONCLUSIONS: Patients with Tecnis ZMB00 multifocal IOL report a higher quality of life regarding the lack of need for optical correction for near vision in their daily activities, but halos in vision at night. Additionally, patients with multifocal IOL achieve similar or better reading quality at near vision and under photopic lighting conditions than patients with monofocal IOL with near vision optical correction.

Retinal structure assessed by OCT as a biomarker of brain development in children born small for gestational age.

PURPOSE: To identify differences in neuronal tissue from retinal and brain structures in children born small for gestational age (SGA) with no abnormality in neonatal brain ultrasonography and no previous neurological impairment, and to evaluate the relationship between retinal structure and brain changes in school-age children born SGA. METHODS: Two cohorts of children were recruited: 25 children born SGA and 25 children born with an appropriate birth weight according to gestational age. All the children underwent an ophthalmic examination, which included retinal imaging using spectral-domain optical coherence tomography, and a brain MRI. MRI images were automatically segmented and global and regional brain volumes were obtained. RESULTS: Although visual function did not differ between both groups, the complex ganglion cell and inner plexiform layers (GCL-IPL) was thinner in SGA children. Total intracranial volume, and global grey and white matter volumes in brain and cerebellum were correlated with birthweight centile, as were certain regional volumes (temporal and parietal lobes, hippocampus and putamen). Abnormal GCL-IPL measurements accurately identified SGA children with the most severe grey and white matter changes in the brain. CONCLUSIONS: SGA children, both preterm and term born, showed evidence of structural abnormalities in the retina, which may be an accurate and non-invasive biomarker of neuronal damage in brain tissue.

Microstructural changes in the retina related to prematurity.

PURPOSE: To assess retinal morphology changes in patients born at different stages of prematurity, accounting for the presence or absence of retinopathy of prematurity (ROP) and comorbidity, using spectral-domain optical coherence tomography (SD OCT). DESIGN: Retrospective cohort study. METHODS: Preterm and term infants underwent an ophthalmologic assessment (best-corrected visual acuity, stereoacuity, cycloplegic refraction and funduscopy). Retinal layers were imaged, segmented, and measured by SD-OCT. In total 114 full term controls and 60 preterm children, classified as late preterm (32-36 weeks gestational age), early preterm (<32 weeks of gestational age) without ROP, and early preterm with previously treated ROP, were included in the study. RESULTS: No retinal structure differences were observed in preterm infants with no treated ROP compared to term infants. Early preterm infants with previous treated ROP had decreased retinal nerve fiber layer (RNFL) thickness in the superior and nasal quadrants, increased RNFL in the temporal quadrant, and a thinner ganglion cell and inner plexiform layer complex (GCL-IPL). Low birthweight percentile was associated with increased foveal thickness and ganglion cell damage (RNFL and GCL-IPL) independent of gestational age. Among all the coexisting events, inflammation and hypoxia were correlated with more severe detrimental effects. CONCLUSIONS: In the absence of treated ROP, prematurity was not associated with disturbed retinal structure. Severe ROP and low birthweight were related to neuronal and axonal damage in the inner retinal layers. Detailed comorbidity should be reviewed when evaluating preterm infants.

Reproducibility of optical coherence tomography measurements in children.

PURPOSE: To determine the interobserver and intraobserver reproducibility of a Fourier-domain optical coherence tomography device (Cirrus HD OCT; Carl Zeiss Meditec, Dublin, California, USA) in normal pediatric eyes. DESIGN: Prospective cross-sectional study. METHODS: One hundred healthy children were recruited prospectively and consecutively. Only 1 randomly chosen eye per subject was included in the study. The eye underwent 3 scans centered on the optic disc and another 3 scans centered on the macula that were acquired by a single operator. A fourth examination was performed by a second operator. Interobserver and intraobserver reproducibility were described by intraclass correlation coefficients (ICCs) and coefficients of variation (COVs). RESULTS: The mean age was 9.15 years (range, 6.22 to 11.31 years; standard deviation, 1.05 years). Mean retinal nerve fiber layer thickness was 99.53 µm (standard deviation, 10.10 µm), and mean macular thickness was 282.91 µm (standard deviation, 11.83 µm). All the parameters evaluated were highly reproducible. Intraobserver COVs of the retinal nerve fiber layer measurements ranged from 2.24% to 5.52%, and the COV of macular thickness was 0.97%. The intraclass correlation coefficient was greater than 0.8 for all the parameters. The interobserver COV ranged from 2.23% to 5.18%, and the COV of macular thickness was 0.82%. In all the evaluated parameters, the intraclass correlation coefficient was more than 0.75. Repeatability was slightly better in children older than 10 years than in children younger than 9 years. CONCLUSIONS: Retinal nerve fiber layer and macular measurements obtained by Fourier-domain optical coherence tomography showed good repeatability for healthy eyes in the pediatric population. Cirrus HD OCT examinations of the retina are reliable in children.

Retinal asymmetry in children measured with optical coherence tomography.

PURPOSE: To determinate the physiological asymmetry of retinal measurements in the pediatric population with Fourier-domain optical coherence tomography (Cirrus HD-OCT). DESIGN: Prospective cross-sectional study. METHODS: Three hundred and fifty-seven healthy children were recruited. All subjects underwent a comprehensive ophthalmologic examination and an evaluation of the retinal nerve fiber layer (RNFL), optic nerve head, and macula with Cirrus OCT. Differences between right and left eyes were calculated and values were compared by means of a paired t test. Normal ranges of interocular differences were established as the 2.5th and the 97.5th percentiles. The correlations between right and left eyes were assessed by the intraclass correlation coefficients. RESULTS: Mean best-corrected visual acuity (logMAR) was -0.01. Differences in the average RNFL between right and left eyes were not statistically significant. The RNFL in the right eyes was thicker in the temporal and nasal quadrants, whereas the left eyes showed thicker RNFL in the superior quadrant. The interocular difference tolerance limits for average RNFL and macular thicknesses were 13.00 µm and 23.20 µm, respectively. There was a strong correlation for all the parameters between the right and the left eyes. CONCLUSIONS: The asymmetry of retinal parameters might be more valuable than the absolute values in assessing certain early diseases. The interocular differences in average RNFL and macular thickness of normal individuals should not exceed 13 µm and 23 µm, respectively, if measured with Cirrus HD-OCT.

Normal reference ranges of optical coherence tomography parameters in childhood.

OBJECTIVE: To report normal reference values for peripapillary retinal nerve fibre layer (RNFL) thickness and optic disc parameters in children from a community population. METHODS: The authors performed a cross-sectional study examining RNFL and optic nerve head (ONH) properties in 358 children aged between 6 and 13 years with no ocular disease. All children underwent an ophthalmic examination that included visual acuity (logMAR), stereopsis assessment (TNO) and optical coherence tomography (Cirrus OCT Zeiss, 'Optic Disc Cube 200×200' protocol). One eye from each subject selected at random was finally analysed. The authors evaluated the influence of height, gender and age on measurements. RESULTS: High-quality scan data were obtained from 357 children and 344 were finally included. The mean age (SD) was 9.16 (1.7) years and the mean (SD) RNFL average thickness was 98.46 (10.79) µm. The temporal quadrant showed the thinnest RNFL (69.35±11.28 µm), followed by the nasal (71.30±13.45 µm), superior (123.65±19.49 µm) and inferior (130.18±18.13 µm) quadrants. The mean rim area (SD) and disc area (SD) were 1.59 (0.33) and 2.05 (0.39) mm(2), respectively. The average cup to disc (C:D) ratio (SD) was 0.43 (0.19). The authors found no differences in any of the parameters with regard to weight, height and gender. CONCLUSIONS: This study demonstrates normative values of RNFL thickness and ONH parameters in a sample of Caucasian children from the general population.