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Purpose: To analyze crystalline lens decentration and tilt in eyes with different axial lengths (ALs) using a swept?source anterior segment optical coherence tomography (SS?AS?OCT). Methods: Patients with normal right eyes who visited our hospital between December 2020 and January 2021 were included in this cross?sectional study. Data on crystalline lens decentration and tilt, AL, aqueous depth (AD), central corneal thickness (CCT), lens thickness (LT), lens vault (LV), anterior chamber width (ACW), and angle ? were collected. Results: A total of 252 patients were included and divided into normal (n = 82), medium–long (n = 89), and long (n = 81) AL groups. The average age of these patients was 43.63 ± 17.02 years. The crystalline lens decentration (0.16 ± 0.08, 0.16 ± 0.09, and 0.20 ± 0.09 mm, P = 0.009) and tilt (4.58° ± 1.42°, 4.06° ± 1.32°, and 2.84° ± 1.19°, P < 0.001) were significantly different among the normal, medium, and long AL groups. Crystalline lens decentration was correlated with AL (r = 0.466, P = 0.004), AD (r = 0.358, P = 0.006), ACW (r = ?0.004, P = 0.020), LT (r = ?0.141, P = 0.013), and LV (r = ?0.371, P = 0.003). Crystalline lens tilt was correlated with age (r = 0.312, P < 0.001), AL (r = ?0.592, P < 0.001), AD (r = ?0.436, P < 0.001), ACW (r = ?0.018, P = 0.004), LT (r = 0.216, P = 0.001), and LV (r = 0.311, P = 0.003). Conclusion: Crystalline lens decentration was positively correlated with AL, and tilt was negatively correlated with AL
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AIM: To evaluate the effect of anterior capsule polishing on visual quality after phacoemulsification.METHODS: Prospective randomized control study. A total of 65 patients(73 eyes)with age-related cataract who underwent phacoemulsification combined with intraocular lens(IOL)implantation in the Emergency General Hospital between November 2021 and June 2022 were included. These patients were randomly assigned to two groups, with one group(anterior polishing group)underwent anterior and posterior capsule polishing(30 cases, 35 eyes), while the other(control group)receive routine posterior capsule polishing(35 cases, 38 eyes). Best corrected visual acuity was observed at 1wk, 1, 3 and 6mo after operation. Area of anterior capsule orifice was measured at 3 and 6mo after operation. Meanwhile, posterior capsular opacification(P score), IOL tilt and decentration were recorded by Pentacam Scheimpflug system. In addition, wavefront aberration, Strehl ratio(SR)of point spread function(PSF)and modulation transfer function(MTF)were evaluated by OPD-Scan Ⅲ.RESULTS: At 1wk, 1, 3 and 6mo after operation, best corrected visual acuity in anterior polishing group is significantly better than that of control group(P<0.05). There were no significant differences in area of anterior capsule opening, P score, IOL decentration, SR of PSF and MTF between two groups at 3 and 6mo after operation(P>0.05). At 3mo follow-up, no significant differences in IOL tilt and wavefront aberration were measured between two groups either(P>0.05). However, IOL tilt [(1.65±0.60)° vs.(2.34±0.43)°, P<0.001] and wavefront aberration(0.03±0.01μm vs. 0.06±0.03μm, P<0.001)in anterior polishing group were significant lower compared to control group at 6mo after operation.CONCLUSION: 360° polishing of anterior and posterior capsule during phacoemulsification can improve best corrected visual quality, with reduced IOL tilt, lower wavefront aberration and better visual quality.
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In recent years, the incidence of myopia in adolescents has been increasing year by year, and how to effectively control the development of myopia has become a research hotspot in the field of public health.The orthokeratology lens has been widely used in myopia control because of its great safety, reliability, and little impact on daily life.The cornea after overnight orthokeratology lens wear can be divided into a relatively flat central treatment zone and a steep peripheral defocus zone.Decentration of the treatment zone is common in clinical practice and is mainly located in the inferior temporal quadrant.Studies have shown that the greater the asymmetry of the anterior corneal surface, the greater the degree of myopia at baseline, and the smaller the diameter of the lens, the greater the deviation of the treatment zone.In addition, decentration of the treatment zone is also related to the gravity of the lens, Bell phenomenon, eyelid, and so on.Large decentration of the treatment zone results in decreased visual quality, including clinical symptoms such as ghosting vision and glare, which may be caused by the increase in comatic aberration.Decentration of the treatment zone may have better myopia control, due to the increase of defocus in the pupil area.Obvious decentration of the treatment zone can be solved by increasing the sagittal height, adjusting the alignment curve, increasing the lens diameter and switching to toric lenses, etc.This article reviewed the factors that affect the decentration of the treatment zone after overnight orthokeratology wear, the influence of decentration on visual quality and myopia control, and the methods to help solve the problems caused by the decentration of the treatment zone, which can guide fitting and replacement of orthokeratology lenses.
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Resumen La teoría del conflicto sociocognitivo del desarrollo cognitivo emerge en la psicología europea en la década de los 70, sobre todo a partir de investigaciones de la llamada Escuela de Psicología Social de Ginebra, que alcanzó notable difusión en las décadas siguientes. Representa una postura neopiagetiana crítica que pone el acento en el papel determinante de la interacción sociocognitiva entre iguales (y más específicamente de la confrontación de puntos de vista distintos) en el desarrollo de la inteligencia. En este artículo se analiza la especificidad del constructo que perimitirá determinar con claridad los elementos teóricos que lo definen y analizar las confusiones y malos entendidos a que dio lugar la notable difusión del paradigma en la psicología y la educación. En una segunda parte se reportan diversas ilustraciones experimentales sobre la temática, fruto de la labor de un equipo compacto de investigadores del IRICE (CONICET). Se trata de una selección en torno a tres ejes de extensión del paradigma: el conflicto como promotor del desarrollo de la operacionalidad formal, el microanálisis de los tipos y modalidades de conflicto sociocognitivo, y el papel de este en el aprendizaje de conocimientos y el cambio conceptual. Estas ilustraciones son solo un ejemplo de la vitalidad que el paradigma generó en el seno de este equipo de trabajo, y marcan una evolución que también se registra en el contexto científico global. El artículo también hace referencia a estos aportes, aunque el acento se pone en las investigaciones propias, entendido como una muestra de construcción colaborativa.
Abstract The theory of socio-cognitive conflict emerges in European Psychology in the 1970s, particularly from the research of the social psychology school of Geneve, that had a strong diffusion in the following years. This theory represents a neo-piagetian critical view of Piaget's theory of cognitive development, in the sense that the attention is focused on the role of peer socio-cognitive interaction (specifically in the social confrontations of different points of view) enhancing cognitive growth. The value of the socio-cognitive conflict promoting cognitive development lies in the decentration effect that it produces. According to this view, disturbance resulting from socio-cognitive conflicts gives way to a superior state of equilibrium. The first part of the article focuses on the theoretical and methodological analysis of the concept. In that way, two periods are distinguished in the evolution of the paradigm attending the inclusion of the communicational analysis of the verbal exchange between subjects. Also, this analysis refers to many confusions and misunderstandings in the larger application of the paradigm to psychology and education. The aim of the second part is to present some experimental illustrations produced by the IRICE (CONICET) research team's work. These illustrations concern three conceptual axes: the application of the paradigm to the development of the formal-logical intelligence, the microanalysis of modalities and types of socio-cognitive conflict, and the extended application of the paradigm to the knowledge learning and conceptual change. The research reported in the first axis concerns the comparison of two experimental conditions: collaborative (dyads) and individual problem solving task (problems of Raven's test), in a sample of 12-13 year old students. The comparison concerns to the performances both in the experimental treatment and in the individual post-test of equivalent problems applied to all participants. Results show, in both cases, the superiority of the collective condition. The second axis focuses on some studies concerning the modalities and types of socio-cognitive conflicts. Particularly, a system of categories for the analysis of the social behavior of children of different ages (4, 8 and 12 years old) in a block construction task (to build a house) is reported. This system differentiates many kinds of interactional behavior: dissociation, dominance-submission (both lower social coordination), cooperation (implicit and explicit) and collaboration (these three are modalities of higher social coordination). The third axis examines some illustrations referring to the extension of paradigm to the epistemic learning. After some references to the difficulty of this extension to the educational settings, two studies are reported. The first one concerns an experimental comparison between a collaborative learning condition (dyads) and an individual learning condition in university students of Psychology and Physics. Also, two kinds of collaborative learning are considered, one that assures alternating of participation, the incentive of argumentation and the reciprocal evaluation (in other words, the promotion of the socio-cognitive conflict), and one that is carried out without any intervention (spontaneous collaborative learning). Results show the superiority of the promoting socio-cognitive conflict condition upon the others, both in a written production and in individual learning post-tests. In a second research the comparison is between three instructional modalities to teach an epistemic topic: expositive, participative (with teacher's scaffolding) and collaborative (only peers), in students of the first grade of secondary education (13 years old), in samples taken from two schools. Results for individual learning show that there are not great differences between the three modalities when the initial level (pre-test) of cognitive competence is high, but not if the cognitive level is low; here the collaborative condition (without scaffolding) has many difficulties. Finally, the article presents some general conclusions specifically concerning the socio-cognitive conflict.
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Objective:To investigate the repeatability and correlation in tilt and decentration measurement of crystalline lens and intraocular lens (IOL) under non-mydriatic and mydriatic conditions using swept-source ocular coherence tomography CASIA2.Methods:A diagnostic test study was conducted.A total of 109 cataract patients (157 eyes) who received phacoemulsification with IOL implantation surgery in the Affiliated Hospital of North Sichuan Medical College from March to July 2020 were enrolled.The decentration and tilt of crystalline lens and IOL under non-mydriatic and mydriatic conditions were measured for three times by a single examiner using CASIA2 before and one week after surgery.The 0.5% compound tropicamide eye drops were used to dilate.Repeatability was evaluated by within-standard deviation, test-retest repeatability (TRT), coefficient of variation (CoV) and intraclass correlation coefficient (ICC). The correlation in decentration and tilt of crystalline lens and IOL between before and after mydriasis was assessed by Pearson correlation coefficient.This study adhered to the Declaration of Helsinki, and the study protocol was approved by an Ethics Committee of the Affiliated Hospital of North Sichuan Medical College (No.2020ER030-1). Written informed consent was obtained from all subjects before any medical examination.Results:The decentration of crystalline lens under non-mydriatic and mydriatic conditions was (0.217±0.112)mm and (0.220±0.110)mm, respectively, and the tilt was (5.017±1.422)° and (5.310±1.645)°, respectively.The decentration of IOL under non-mydriatic and mydriatic conditions was (0.245±0.136)mm and (0.250±0.145)mm, respectively, and the tilt was (5.144±1.345)° and (5.437±1.646)°, respectively.No significant difference was found between non-mydriatic and mydriatic conditions (all at P>0.05). Under both non-mydriatic and mydriatic conditions, the crystalline lenses of both eyes decentered and tilted toward the inferotemporal direction, and the IOL of right eyes decentered toward the inferior and tilted toward the inferotemporal direction, and the IOL of left eyes decentered and tilted toward the inferotemporal direction.Except the crystalline lens decentration, the measurement repeatability of crystalline lens tilt, IOL decentration and tilt in cataract patients before and after mydriasis was good, with ICC range in 0.815-0.984, TRT<50% and CoV≤14.840%.The measurement repeatability of crystalline lens decentration was poor, and the measurement repeatability of decentration axis, tilt and tilt axis of crystalline lens, and the repeatability of decentration and tilt of IOL were good in both eyes, with ICC range in 0.757-0.998, TRT<50% and CoV≤17.763%.There were good correlations in decentration, decentration axis, tilt and tilt axis of crystalline lens and IOL between non-mydriatic and mydriatic conditions (all r≥0.679, all at P<0.01). Conclusions:The measurement repeatability of decentration axis, tilt and tilt axis of crystalline lens and IOL, as well as the decentration of IOL by CASIA2 before and after mydriasis is good.The correlations of the measured parameters before and after mydriasis are good.
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AIM: To investigate the correlation between postoperative lens decentration and tilt and visual quality in eyes implanted with aspherical intraocular lens(IOL)by using a new anterior segment swept-source optical coherence tomography(OCT)CASIA2.METHODS: An observational study. A total of 90 eyes of 62 participants who underwent age-related cataract surgery at 1mo were included. Using CASIA2 by an experienced examiner, IOL tilt and decentration were obtained three consecutive times after mydriasis and the vector mean values were calculated. Double-pass optical quality analysis system(OQAS)and wavefront aberration instrument KR-1W were used for the visual quality measurements, including the total high-order aberration(tHOA), spherical aberration(SA), Coma, objective scatter index(OSI), modulation transfer function cut off frequency(MTF cut off)and Strehl ratio(SR)at 4 and 6mm pupil diameter.RESULTS: IOL decentration was positively correlated with SA(r=0.347, P=0.001)and OSI(r=0.343, P=0.002)at 4mm pupil diameter, and it was negatively correlated with MTF cut off(r=-0.244, P=0.032). There was no significant correlation between IOL decentration and tHOA, Coma and SR. IOL tilt was negatively correlated with MTF cut off(r=0.-345, P=0.002)and SR(r=-0.256, P=0.023)at 4mm pupil diameter, but it was not correlated with tHOA, SA, Coma and OSI. There were no significant correlations between the IOL decentration and tilt and tHOA, SA, Coma, MTF cut off and SR at 6mm pupil diameter.CONCLUSION: After aspherical IOL implantation in age-related cataract patients, IOL decentration was weakly correlated with SA at 4mm pupil diameter, while decentration and tilt were not significantly correlated with other higher-order aberrations. The decentration and tilt were weakly correlated with OSI value and MTF cut off value of the visual quality parameters. The results suggest that clinicians should pay more attention to higher-order aberrations and visual quality during precise cataract surgery.
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@#AIM: To investigate the related factors of orthokeraology(ortho-K)decentration.<p>METHODS: Within a prospective study, 88 eyes of 88 patients who visited to our center between July 2014 and December 2016 were enrolled. To verify the possible role of the spherical equivalent(SE), the corneal astigmatism(CA), e value, steep K, flat K, front curvature asymmetry index(SIf)and age in the ortho-K location prediction.<p>RESULTS: This study included 24 eyes of grade Ⅰ decentration, 26 eyes with grade Ⅱ, 25 eyes with grade Ⅲ, and 13 eyes with grade Ⅳ, by which based on the decentration system that published by our team. One-way ANOVA showed that there was statically significant difference of SE, Ks and Kf in different grading groups(<i>P</i><0.05). Multiple linear regression analysis showed SE was negatively correlated with the decentration(<i>P</i><0.01). The others factors such as the CA, e, Ks, Kf, SIf, age has weak correlation with the ortho-K decentration.<p>CONCLUSION: The SE might be the main factor which lead to the ortho-K decentration.
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@#AIM: To evaluate the influence of lens capsule contraction on intraocular lens(IOL)decentration after cataract surgery.<p>METHODS: Totally 40 cases(40 eyes)of senile cataract underwent phacoemulsification combined with IOL implantation. Within 3mo after operation, the anterior capsule opening area was measured by Photoshop software, the IOL decentration was measured by iTrace visual quality analyzer. The influence of anterior capsule opening area on IOL decentration was assessed by Pearson correlation analysis.<p>RESULTS: At 1d, 1mo and 3mo after operation, anterior capsule opening area was gradually reduced, the difference between different time points was statistically significant(<i>P</i><0.01); IOL decentration gradually increased, and the difference between different time points was statistically significant(<i>P</i><0.01); the visual acuity of patients decreased gradually, and the difference between different time points was statistically significant(<i>P</i><0.01). The change of anterior capsule opening area was positively correlated with IOL decentration(<i>r</i>=0.566, <i>P</i><0.05), but there was no significant correlation between visual acuity and IOL decentration(<i>r</i>= -0.104, <i>P</i>> 0.05), the change of anterior capsule opening area was negatively correlated with the initial anterior capsule opening area(<i>r</i>= -0.476, <i>P</i><0.05).<p>CONCLUSION: The anterior capsule contraction after cataract surgery can lead to IOL decentration.
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Objective To observe the stability of intraocular lens (IOL) in primary angle-closure glaucoma by ultra-long scan depth spectral domain optical coherence tomography (UL-OCT) after the phacoemulsification.Methods Totally 42 patients (42 eyes) with primary closed-angle glaucoma (PACG) and age-,gender-matched 40 patients (40 eyes) with age-related cataract were included in the study.All of patients underwent phacoemulsification combined with softec HD IOL implantation.Images were obtained by UL-OCT in 1 week,1 month and 3 months after the surgery for the calculation and analysis of the IOL decentration,tilt and the space between IOL and posterior capsule (IOL-PC space).And finally the intergroup differences at the different time-points were compared with the independent sample t test.Results The IOL decentration after 1 week,1 month and 3 months was (0.182 ± 0.054) mm,(0.232 ±0.081)mm,(0.183 ±0.089) mm in the PACG group,and (0.342 ± 0.141)mm,(0.288 ±0.110)mm,(0.249 ± 0.132)mm in the ARC group.There was statistically significant difference in IOL decentration 1 week after surgery between the two groups (P =0.006),but the differences in this variable at the other two time-points between the two groups were not statistically significant (both P ＞ 0.05).The tilt on the vertical axis at 1 week,1 month and 3 months after surgery was (3.670 ± 6.610) °,(-0.940 ± 4.730) °,(0.540±9.510)° in the PACG group,and (-4.090±7.610)°,(-5.100±5.530)°,(-1.430 ± 8.800) ° in the ARC group.The tilt on the vertical axis of the PACG group was less than that of the ARC group at 1 week after surgery,with statistical difference (P =0.025),but there was no significant difference in this variable at the other two time-points (both P ＞ 0.05).Moreover,the tilt on the horizontal axis showed no statistically significant differences (all P ＞ 0.05).The IOL-PC space on horizontal axis at 1 week,1 month and 3 months after surgery was (0.111 ±0.091)mm2,(0.044 ±0.066)mm2,(0.055 ±0.055) mm2 in the PACG group,and (0 176 ±0.213) mm2,(0.255 ±0.303) mm2,(0.059 ± 0.066) mm2 in the ARC group.The IOL-PC space on horizontal axis of the PACG group was less than that of the ARC group at 1 month after surgery,with statistical difference (P =0.045),but there was no significant difference in this variable at the other two time-points (both P ＞ 0.05).Moreover,the IOL-PC space on vertical axis showed no statistically significantdifferences (all P ＞ 0.05).Conclusion The stability of Softec IOL in the PACG group is better than that in ARC group in 3 months after phacoemulsification.
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Objective To evaluate the clinical effect of femtosecond laser assisted cataract surgery with Toric IOL implantation on correcting astigmatism and IOL rotating stability.Methods A prospective,nonrandomized,controlled study was conducted in 68 patients (82 eyes) diagnosed as age-related cataract with more than 1.0 diopter (D) regular astigmatism,including 41 eyes undergoing Toric IOL implantation with femtosecond laser assisted cataract surgery,and the other eyes receiving Toric IOL with phacoemulsification.And observation was performed for the uncorrected visual acuity (UCVA) before operation and 6 months after operation,preoperative corneal astigmatism,anticipated and postoperative residual astigmatism 6 months after operation.Then,comparison was performed for the degree of Toric lens axis rotation,as well as the horizontal and vertical movement of the IOL and the degree of vertical deflection in the capsule at 1,3,and 6 months after operation.Results In the observation group,preoperative UCVA (logMAR),preoperative corneal astigmatism,postoperative BCVA and the residual astigmatism at 6 months after operation was 1.03 ± 0.32,(2.09 ± 0.73) D,0.13 ± 0.11 and (0.33 ± 0.27) D,respectively,while the corresponding data in the control group was 0.92 ± 0.40,(1.69 ± 0.64) D,0.13 ± 0.09,(0.26 ± 0.22) D;the postoperative visual acuity in both groups was significantly improved,and residual astigmatism was significantly decreased at 6 months after operation (all P ＜ 0.001).There was no significant difference in Toric lens axis after femtosecond laser assisted surgery and phacoemulsification at 1 month,3 months,6 months after operation (all P ＞ 0.05),but the differences in the IOL movement in horizontal and vertical direction were statistically significant at the different time-points (all P ＜ 0.05),and there was significant differences in the degree of vertical deflection (all P ＜ 0.05).Conclusion Both femtosecond laser assisted cataract surgery and phacoemulsification combined with Toric IOL can achieve a better stability and predictability.
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Background Cornea astigmatism can be effectively corrected by implanting Toric intraocular lens (IOL) during cataract surgery and therefore improve visual acuity of patients.However,the decentration and rotation position errors were inevitable sometime.What's the difference of effect of position errors on quality of image between spherical IOL and Toric IOL needs further research.Objective This study was to evaluate the optical performance and wavefront with rotation and decentration of Toric IOL.Methods Different decentration for SN60AT IOL(spherical IOL) and Toric IOL in Hwey-Lan Lion model eyes was set with the role as follows:decentration 0.25 mm to 0.75 mm in a 5°-interval from 0° to 90°.Furthermore,Toric IOL was rotated at 5° and 10°,respectively.Then the image performances of SN60AT IOL and Toric IOL at different decentration distances and rotated degrees were evaluated with modulation transfer function (MTF) and value of wavefront aberration under all conditions.Results At the centration,the MTF curves of spherical IOL and Toric IOL were similar under 3,4 and 5 mm pupil diameter at each spatial frequency.Under the condition of 4 mm pupil diameter,when the decentration was 0.25 mm,the MTF values of SN60AT IOL at 6 c/d and 12 c/d were 0.581 087 and 0.411 960,respectively.T3 IOL were 0.454 259 and 0.382 313,T4 IOL were 0.426 020 and 0.360 490,T5 IOL were 0.425 606 and 0.359 877.When the decentration was 0.50 mm,the MTF values of SN60AT at 6 c/d and 12 c/d were 0.573 073 and 0.412 787,respectively.T3 IOL were 0.450943 and 0.379481,T4 IOL were 0.423 153 and 0.356 664,T5 IOL were 0.422 881 and 0.356 230.When the decentration was 0.75 mm,the MTF values of SN60AT at 6 c/d and 12 c/d were 0.560 038 and 0.413 624,respectively.T3 IOL were 0.445 597 and 0.374 322,T4 IOL were 0.418 522 and 0.350 087,T5 IOL were 0.418 468 and 0.349 976.When the IOL decentralized along 0°,5°,10°,90°meridian line,the MTF values were almostly same.The root mean square (RMS) of spherical IOL and Toric IOL was increased when the IOL decentralized from 0 mm to 0.75 mm,with the most increasing level in coma aberration and slight increase in trefoil aberration.When the T4 IOL decentralized from centre to 0.75 mm,the coma increased from 0 to C(3,-1)-0.049 79 μm,C (3,1)-0.037 59 μm and the trefoil aberration increased from 0 to C (3,3) 0.005 72 μm,C (3,-3) 0.004 64 μm.With the increase of rotation degrees (from 5°to 10°) of Toric IOL,the MTF was worse at high spatial frequency.Toric IOL rotation caused the increase of astigmatism and residual astigmatism and spherical error,but not high order aberration.Conclusions The tolerance of Toric IOL to decentration is very close to the spherical IOL,and optical performance is only associated with the amount of decentration but not direction.The aberration caused by Toric IOL decentration is mainly coma.The rotation of Toric IOL causes astigmatism error but not high order aberrations.
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The stability of the intraocular lens ( IOL ) after cataract surgery is composed of decentration, tilt, rotation, and the change of anterior chamber depth. Its stability is an important factor affecting postoperative visual quality. By analyzing the related factors which influence the stability of intraocular lens, improvements can be identified for future cataract operations. The stability of intraocular lens is influenced by many factors: intraocular structure, the size and the symmetry of intraoperative capsulorhexis, the position of the intraocular lens, the material and design of the intraocular lens, etc. In order to improve the patient's vision, cataract surgeries have been experiencing an evolution. IOL material have also been contributing to such innovations.
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Aim of Study: To describe a simplified ab-interno cow-hitch suture fixation technique for repositioning decentered posterior chamber intraocular lens (PC IOL). Materials and Methods: Two cases are presented with the surgical correction of decentered and subluxated IOL. Ab-interno scleral suture fixation technique with hitch-cow knot in the eye was performed with a ciliary sulcus guide instrument and 1 year follow-up was completed. Results: Both of the patients had well centered lenses postoperatively. Corrected distant and near visual acuities of the patients were improved. There was no significant postoperative complication. In the follow-up period of 1 year, no evidence of suture erosion was found. Conclusions: Ab-interno scleral suture loop fixation with hitch-cow knot in the eye was effective in repositioning decentered or subluxated PC IOLs with excellent postoperative centered lenses and visual outcomes.
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PURPOSE: To evaluate the effects of continuous curvilinear capsulorhexis, intraocular lens (IOL) decentration and tilt on postoperative clinical outcomes after cataract surgery. METHODS: We reviewed 62 eyes of 52 patients who underwent cataract surgery and measured the uncorrected visual acuity, best corrected visual acuity and manifest refraction preoperatively and 3 months postoperatively. IOL decentration on anterior segment photography and IOL tilt on anterior optical coherent tomography were analyzed and correlations of postoperative uncorrected visual acuity, best corrected visual acuity, and higher order aberrations were evaluated. In addition, we inspected the relationship of size and decentration of continuous curvilinear capsulorhexis (CCC) intraoperatively with the change in IOL position postoperatively. RESULTS: The average size of CCC was 5.40 ± 0.51 mm (4.12-6.24 mm) and the average decentration of CCC was 0.30 ± 0.19 mm (0.09-1.21 mm) intraoperatively. The average decentration of IOL was 0.23 ± 0.15 mm (0.00-0.71 mm) and the average IOL tilt was 1.43 ± 0.73° (0.00-4.22°) postoperatively. Intraoperative CCC size and decentration were associated with postoperative IOL decentration (p = 0.01, p < 0.001), but not with IOL tilt (p = 0.69, p = 0.52). There were no significant correlations between IOL decentration and tilt with postoperative visual outcomes and higher order aberrations. CONCLUSIONS: The CCC size and decentration can affect the IOL decentration, but IOL decentration and tilt do not have a significant impact on clinical outcomes after cataract surgery.
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Humans , Capsulorhexis , Cataract , Lenses, Intraocular , Photography , Visual AcuityABSTRACT
PURPOSE: To evaluate the effects of continuous curvilinear capsulorhexis, intraocular lens (IOL) decentration and tilt on postoperative clinical outcomes after cataract surgery. METHODS: We reviewed 62 eyes of 52 patients who underwent cataract surgery and measured the uncorrected visual acuity, best corrected visual acuity and manifest refraction preoperatively and 3 months postoperatively. IOL decentration on anterior segment photography and IOL tilt on anterior optical coherent tomography were analyzed and correlations of postoperative uncorrected visual acuity, best corrected visual acuity, and higher order aberrations were evaluated. In addition, we inspected the relationship of size and decentration of continuous curvilinear capsulorhexis (CCC) intraoperatively with the change in IOL position postoperatively. RESULTS: The average size of CCC was 5.40 ± 0.51 mm (4.12-6.24 mm) and the average decentration of CCC was 0.30 ± 0.19 mm (0.09-1.21 mm) intraoperatively. The average decentration of IOL was 0.23 ± 0.15 mm (0.00-0.71 mm) and the average IOL tilt was 1.43 ± 0.73° (0.00-4.22°) postoperatively. Intraoperative CCC size and decentration were associated with postoperative IOL decentration (p = 0.01, p < 0.001), but not with IOL tilt (p = 0.69, p = 0.52). There were no significant correlations between IOL decentration and tilt with postoperative visual outcomes and higher order aberrations. CONCLUSIONS: The CCC size and decentration can affect the IOL decentration, but IOL decentration and tilt do not have a significant impact on clinical outcomes after cataract surgery.
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Humans , Capsulorhexis , Cataract , Lenses, Intraocular , Photography , Visual AcuityABSTRACT
PURPOSE: To evaluate the anterior chamber depth (ACD), extent of intraocular lens (IOL) tilt, and decentration and refractive error after transscleral fixation of IOL. METHODS: We retrospectively reviewed the medical records of 17 cases with transscleral fixation of IOL (6 with aphakia, 5 with IOL dislocation, and 6 with lens subluxation). The acrylic IOL (MN60AC(R)) was fixated in 12 eyes and the polymethylmethacrylate IOL (CZ70BD(R)) was fixated in 5 eyes at 1.0 mm posterior from the limbus. We analyzed the ACD, extent of IOL tilt and decentration, manifest refraction, refractive error, higher order aberration, and corneal endothelium at 2 weeks, 1 month and 2 months postoperatively. RESULTS: The mean ACD was 3.36 +/- 0.11 mm, 3.30 +/- 0.12 mm, and 3.27 +/- 0.13 mm, the mean extent of IOL tilt was 4.61 +/- 0.12degrees, 4.65 +/- 0.14degrees, and 4.60 +/- 0.12degrees and the mean extent of IOL decentration was 0.43 +/- 0.01 mm, 0.45 +/- 0.01 mm, and 0.45 +/- 0.01 mm at 2 weeks, 1 month and 2 months postoperatively, respectively in eyes with transscleral fixation of IOL. The ACD was shallower and the extent of IOL tilt and decentration was greater than with IOL in-the-bag insertion patients. The mean refractive errors were -0.55 +/- 0.27 D, -0.63 +/- 0.24 D, and -0.69 +/- 0.19 D at the same period, respectively. CONCLUSIONS: Although postoperative refractive error is influenced by surgeon factors such as incision size, distance of fixation suture from limbus, and tightness of suture material, according to our results, an IOL 0.75 D more hyperopic than predicted should be selected in transscleral fixation of IOL at 1.0 mm posterior from the limbus. Additionally, each surgeon should assess their specific results and modify the lens calculations accordingly.
Subject(s)
Humans , Anterior Chamber , Aphakia , Joint Dislocations , Endothelium, Corneal , Lenses, Intraocular , Medical Records , Polymethyl Methacrylate , Refractive Errors , Retrospective Studies , SuturesABSTRACT
AlM:To compare the differences of tilt and decentration of two aspheric posterior chamber intraocular lens ( PC-lOL) implantation by ultrasonic biomicroscope ( UBM) .METHODS:Thirty-seven patients ( 45 eyes ) underwent cataract surgery were distributed to two groups randomly. Group A was implanted with Akreos AO ( Bausch &Lomb; four-haptic ) while group B implanted with ZCB00 ( Abbott Medical Optics, lnc. AMO; two-haptic) . All eyes underwent standard phacoemulsification with intraocular lens implantation. Diameter of capsulotomy was recorded. One month postoperatively, vision, best-corrected visual acuity ( BCVA) assessment, slit lamp examination, and anterior chamber depth ( ACD ) measured by UBM were performed. Tilt and decentration were measured horizontally and vertically, and total tilt and decentration were calculated by geometry method. RESULTS:No statistical difference was found in BCVA and diameter of capsulotomy between two groups ( P>0. 05). The mean ACD of group A and group B were 3. 86mm ± 0. 31mm and 4. 14mm ± 0. 31mm respectively, which showed it had statistically significant difference ( P0. 05).CONCLUSlON:Two-haptic lOL shows no difference in tilt and decentration with four-haptic lOL postoperatively.
ABSTRACT
lntraocular lens ( lOL) often has different degrees of tilt, decentration and rotation in the eye. The deflection of lOL is an important factor to impact on the visual quality of the patients with cataract surgeries. Vision was commonly used to evaluate visual quality before. ln recent years, some new methods are also introduced to evaluate visual quality, such as optical aberration, modulation transfer function ( MTF ) and subjective visual perception. They show that the lOL deflection will cause decreases in eyesight and MTF, cause increase in aberration, lead to ametropia and so on. Therefore, a better evaluation of the effects of lOL deflection on visual quality, has significance for lOL selection, positioning and cataract individualized treatment.
ABSTRACT
PURPOSE: To evaluate the effect of the amount of cylindrical correction on the accuracy of geometric corneal center-adjusted ablation centration selected by the surgeon in advanced surface ablation-photorefractive keratectomy (ASA-PRK). METHODS: Ninety-five myopic eyes of 62 patients who underwent ASA-PRK were divided into three groups based on the amount of myopic cylindrical correction: Group 1 or =-0.50 D and or =-1.00 D, 28 eyes. The distances and distribution of the ablation centers from the entrance pupil center were analyzed by corneal topography at one month after ASA-PRK. Risk factors for decentration (>0.3 mm) were determined from patient-related factors such as gender, age, laterality, central corneal thickness, and order of procedure and surgery-related factors such as amount of spherical correction, ablation depth, vertical scale bar percentage, and learning effect of surgeon. RESULTS: Mean decentration was 0.26 +/- 0.15 mm (0.04 to 0.83 mm). There was no statistically significant difference in the amount of decentration among the three groups (p = 0.879). Superior-nasal displacement (53.7%) of the ablation center most frequently occurred after ASA-PRK. The amount of decentration among the three groups was not dependent on either patient-related or surgery-related factors. CONCLUSIONS: ASA-PRK using the surgeon-selected ablation center with adjustment toward the geometric corneal center was found to be highly accurate in ablation centration and did not influence the amount of ablation decentration regardless of the amount of myopic cylindrical correction.