Variations of OCT measurements corrected for the magnification effect according to axial length and refractive error in children

The aim of this paper was to examine the distribution of macular, retinal nerve fiber layer (RNFL) thickness and optic disc parameters of myopic and hyperopic eyes in comparison with emmetropic control eyes and to investigate their variation according to axial length (AL) and spherical equivalent (SE) in healthy children. Methods: This study included 293 pairs of eyes of 293 children (145 boys and 148 girls), ranging in age from 6 to 17 years. Subjects were divided according to SE in control (emmetropia, 99 children), myopia (100 children) and hyperopia (94 children) groups and according to axial AL in 68 short ((Formula presented.)22.00(Formula presented.)mm, 68), medium (from (Formula presented.)22.00(Formula presented.)mm to 25.00(Formula presented.)mm, 189) and long eyes ((Formula presented.)25.00(Formula presented.)mm, 36). Macular parameters, RNFL thickness and optic disc morphology were assessed by the CirrusTM HD-OCT. AL was measured using the IOL-Master system. Littmann’s formula was used for calculating the corrected AL-related ocular magnification. Results: Mean age ((Formula presented.)(Formula presented.)SD) was 10.84(Formula presented.)(Formula presented.)(Formula presented.)3.05 years; mean ((Formula presented.)(Formula presented.)SD) SE was (Formula presented.)0.14(Formula presented.)(Formula presented.)(Formula presented.)0.51 D (range from (Formula presented.)8.75 to (Formula presented.)8.25 D) and mean AL ((Formula presented.)(Formula presented.)SD) was 23.12(Formula presented.)(Formula presented.)(Formula presented.)1.49. Average RNFL thickness, average macular thickness and macular volume decreased as AL and myopia increased. No correlations between AL/SE and optic disc parameters were found after correcting for magnification effect. Conclusions: AL and refractive error affect measurements of macular and RNFL thickness in healthy children. To make a correct interpretation of OCT measurements, ocular magnification effect should be taken into account by clinicians or OCT manufacturers.Postprint (published version

System for objective assessment of the accommodation response during subjective refraction

Purpose: To evaluate a system based on a Hartmann–Shack wavefront sensor attached to a phoropter that allows the user to obtain real-time information about the refractive state of the eye and the accommodation response (AR). Methods: The objective refractions (ME) and ARs of 73 subjects (50 women, 23 men; ages, 19–69 years) were assessed with the system developed while placing in the phoropter the subjective refraction (MS) plus a set of trial lenses with differences in spherical equivalent power (¿M) between ±2 diopters (D). Results: The objective estimations (ME) showed a good correlation with the subjective values (MS) (r = 0.989; P < 0.001). The means of the ARs presented a region where the accommodation remained stable (¿M from +2 D to about 0 D), followed by another in which the response increased progressively (¿M from about 0 to -2 D) with the magnitude of the accommodation stimulus. The analysis of variance within subjects applied to ARs introducing age and MS as covariates showed an increasing effect size of age from medium to large between ¿M of -0.5 and -2 D. In contrast, MS had a medium effect size (between ¿M of +2 and 0 D). Conclusions: The implemented system permitted an objective estimation of the refraction of the eye and its AR. Because it is coupled to a phoropter, the system can be used to retrieve the AR during subjective refraction procedures. Translational Relevance: The developed system can be used as a supporting tool during subjective refraction to provide certainty about the true state of accommodation."This publication is part of the project PID2020-112527RB-I00, funded by MCIN/AEI/10.13039/501100011033, and the Miopmilla Program, funded by the Official College of Opticians and Optometrists of Catalonia. Aina Turull-Mallofré gratefully acknowledges the Universitat Politècnica de Catalunya and Banco Santander for the financial support of her predoctoral grant FPI-UPC. Mikel Aldaba is a Serra Húnter Fellow."Peer ReviewedPostprint (published version

System based on the contrast of Purkinje images to measure corneal and lens scattering

Current methods to measure intraocular scattering provide information on the total scattered light, which consists of the combined contributions originating from different ocular structures. In this work, we propose a technique for the objective and independent assessment of scattering caused by the cornea and the lens based on the analysis of the contrast of the third and fourth Purkinje images. The technique is preliminarily validated first by using artificial eyes with different levels of corneal and lens scattering; second, it is validated in eyes wearing customized contact lenses to simulate corneal scattering and eyes with nuclear cataracts. Finally, it is tested on a larger population of eyes with cataracts and corneal disorders to prove its clinical usefulness.Postprint (published version

Double-pass technique and compensation-comparison method in eyes with cataract

PURPOSE To clinically assess the objective scatter index (OSI) obtained from double-pass images and the log(s) parameter measured with the direct compensation-comparison psychophysical technique in eyes with cataract. SETTING Ophthalmology Service, Terrassa Hospital, Barcelona, Spain. DESIGN Prospective observational case series. METHODS The analysis comprised eyes diagnosed with nuclear, cortical, or posterior subcapsular cataracts and healthy eyes (control group). Patient examinations included assessment of the manifest subjective refraction, corrected distance visual acuity, contrast sensitivity, and cataract grade using the Lens Opacities Classification System III (LOCS III) score. The protocol also included the straylight (log[s]) measured by the C-Quant device, measurement of the objective optical quality (Strehl ratio and modulation transfer function cutoff frequency), and the OSI (HD Analyzer). RESULTS Significant correlations with LOCS III classification were found in terms of log(s) and OSI, although they were slightly stronger with OSI for all cataract types, which could be attributable to higher-order aberrations. The OSI and log(s) shared approximately 44% of the scattering estimation and to coincide on the visual function decline with scattering for the 3 cataract types evaluated. Limits to discriminate between healthy and cataractous eyes and sensitivity and specificity values were 1.15 (sensitivity 91%, specificity 100%) for log(s) and 1.18 (sensitivity 89%, specificity 100%) for OSI (P < .05). CONCLUSIONS Both instruments provide complementary information to diagnose cataracts and follow patients. Although backscattered light from deeper retinal layers can have an effect on OSI, the double-pass image provides information to grade different types of cataract when assessing cataractous eyes for treatment.Preprin

Aplicació d’eines TIC a la millora de les competències clíniques en l’àmbit de l’òptica i l’optometria: “OPTOstream”

Actualment, l’estudiantat de la Facultat d’Òptica i Optometria de les assignatures clíniques (Grau i Màster) participen de forma activa en l’atenció de pacient reals, sota la supervisió del professorat. Els casos atesos durant les sessions pràctiques es plantegen i discuteixen en les sessions de seminari amb els docents i la resta del grup. Malgrat el valor docent d’aquesta metodologia, l’estudiant no tenia la possibilitat de comprovar la seva actuació durant l’atenció d’un cas real, a partir de les observacions del docent. Aquesta situació dificulta un aprofitament òptim de l’experiència d’aprenentatge per part de l’estudiant. La incorporació de solucions tècniques contrastades en l’àmbit de la formació, com és el cas de l’enregistrament i visionat posterior o en temps real de casos, permeten a l’estudiant participar més activament en el seu procés d’aprenentatge i contribueixen a fer més efectiva l’adquisició de determinats coneixements i competències bàsiques per al desenvolupament de la seva carrera professional i investigadora. El projecte “OPTOstream” ha permès desenvolupar una metodologia pròpia basada en l’elaboració i anàlisi posterior de casos enregistrats en vídeo o bé la projecció en temps real de les actuacions clíniques al nou auditori de la Facultat.Peer Reviewe

Suitability of open-field autorefractors as pupillometers and instrument design effects

AIM: To determine the agreement and repeatability of the pupil measurement obtained with VIP-200 (Neuroptics), PowerRef II (Plusoptix), WAM-5500 (Grand Seiko) and study the effects of instrument design on pupillometry. METHODS: Forty patients were measured twice in low, mid and high mesopic. Repeatability was analyzed with the within-subject standard deviation (Sw) and paired t-tests. Agreement was studied with Bland-Altman plots and repeated measures ANOVA. Instrument design analysis consisted on measuring pupil size with PowerRef II simulating monocular and binocular conditions as well as with proximity cues and without proximity cues. RESULTS: The mean difference (standard deviation) between test-retest for low, mid and high mesopic conditions were, respectively: -0.09 (+/- 0.16), -0.05 (+/- 0.18) and -0.08 (+/- 0.23) mm for Neuroptics, -0.05 (+/- 0.17), -0.12 (+/- 0.23) and -0.17 (+/- 0.34) mm for WAM-5500, -0.04 (+/- 0.27), -0.13 (+/- 0.37) and -0.11 (+/- 0.28) mm for PowerRef II. Regarding agreement with Neuroptics, the mean difference for low, mid and high mesopic conditions were, respectively: -0.48 (+/- 0.35), -0.83 (+/- 0.52) and -0.38 (+/- 0.56) mm for WAM-5500, -0.28 (+/- 0.56),-0.70 (+/- 0.55) and -0.61 (+/- 0.54) mm for PowerRef II. The mean difference of binocular minus monocular pupil measurements was: -0.83 (+/- 0.87) mm; and with proximity cues minus without proximity cues was: -0.30 (+/- 0.77) mm. CONCLUSION: All the instruments show similar repeatability. In all illumination conditions, agreement of Neuroptics with WAM-5500 and PowerRef II is not good enough, which can be partially induced due to their open field design.Postprint (published version

Grading nuclear, cortical and posterior subcapsular cataracts using an objective scatter index measured with a double-pass system

Postprint (author's final draft

Líneas de investigación en óptica visual y tecnología del color en el CD6

Postprint (author's final draft

Trabajos de investigación en óptica visual y tecnología del color en el CD6

Postprint (author's final draft

Calidad óptica ocular en ojos sometidos a cirugía refractiva y afecciones patológicas

This dissertation deals with the evaluation of ocular optical quality in two types of patients. First, are patients who have undergone different surgical techniques of refractive surgery to correct different degrees of myopia and astigmatism, either by techniques based on corneal laser ablation or by implementing different types of phakic intraocular lenses, and in the second one patients with eye diseases with visual impairment have been evaluated. Specifically they are rated corneal alterations, epithelial and dystrophies, and patients with amblyopia. They all found different factors affecting the ocular optical quality could be significant in the diagnosis and management of eye diseases. In the clinical studies to determine ocular optical quality changes between pre and postoperative refractive surgery for myopia it has been able to evaluate the safety and efficacy of different techniques. In the study of corneal disorders it has been determined ocular optical quality changes in different type’s alterations of ocular structures. In the study of amblyopia have been compared the ocular optical quality in patients with amblyopia, amblyopic treated patients and a healthy control group. In all studies it has determined the existence of correlations with subjective clinical psychophysical tests of visual function, specifically visual acuity and contrast sensitivity. It has been shown that there are significant differences between the levels of visual function and ocular optical quality. These studies have led to four publications in scientific journals and is planned to publish two more. 13 have also been made at conferences of national and international. The work in this thesis has led to a patent which is in operation by the company Visiometrics SL.Esta tesis doctoral aborda la evaluación de la calidad óptica ocular en dos tipologías de pacientes. La primera son pacientes que han sido sometidos a diferentes técnicas quirúrgicas de cirugía refractiva para la corrección de diferentes grados de miopía y astigmatismo, ya sea mediante distintas técnicas de ablación corneal con láser o mediante la implantación de diferentes tipos de diseño de lentes intraoculares fáquicas, y en la segunda se han evaluado diversas patologías oculares con afectación visual. Concretamente se han valorado alteraciones corneales, epiteliales y distrofias, así como pacientes con ambliopía. En todas ellas se han encontrado diversos factores que afectan a la calidad óptica ocular que pueden ser significativas para el diagnóstico y seguimiento de patologías oculares. En los estudios clínicos para determinar los cambios en la calidad óptica ocular entre el pre y postoperatorio de cirugía refractiva de la miopía se ha podido evaluar la seguridad y eficacia de las diferentes técnicas. En el estudio de alteraciones corneales se han determinado los cambios en la calidad óptica ocular en diferentes tipos de lesiones de estructuras oculares. Y en el estudio de ambliopía se ha comparado la calidad óptica ocular entre pacientes con ambliopía, pacientes amblíopes tratados y un grupo sano de control. En todos los estudios se ha determinado la existencia de correlaciones con pruebas psicofísicas subjetivas clínicas de la función visual, concretamente con la agudeza visual y la sensibilidad al contraste. Se ha demostrado que existen diferencias significativas entre los niveles de la función visual y la calidad óptica ocular Estos estudios han dado lugar a cuatro publicaciones en revistas científicas especializadas y está previsto publicar dos más. También han sido realizadas 13 comunicaciones en congresos de carácter nacional e internacional. El trabajo desarrollado en esta tesis ha dado lugar a una patente que se encuentra en explotación por parte de la empresa Visiometrics S.L.Postprint (published version