Comparison of corneal epithelial remodeling and corneal aberration changes after FS-LASIK and FS-LASIK Xtra / 中华实验眼科杂志

Objective:To investigate the status of corneal epithelial remodeling and changes in corneal aberration after femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) and FS-LASIK combined with corneal collagen cross-linking (FS-LASIK Xtra), and to analyze the relationship between corneal epithelial thickness (CET) and corneal aberration.Methods:A cohort study was conducted.A total of 172 patients (172 eyes) who underwent FS-LASIK at Yinhai Eye Hospital of Chengdu University of Traditional Chinese Medicine were enrolled from June 2021 to February 2022.The 172 eyes were divided into FS-LASIK group (94 eyes) and FS-LASIK Xtra group (78 eyes) according to the surgical procedure, with a total follow-up of 6 months.The cornea was divided into a central 2-mm ring and a ring of 2-5 mm centered on the central cornea.CET at 9 regions in the central 0-5 mm area was measured by OCT before and at 1, 3 and 6 months after surgery, and the corneal higher-order aberration (HOA) was measured by the iTrace visual function analyzer.The main outcomes were the increase in CET (ΔCET), and corneal HOA at 6 months after surgery.The relationship between central corneal ΔCET and corneal aberration was analyzed.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Yinhai Eye Hospital of Chengdu University of Traditional Chinese Medicine (No.2021yh-009). Written informed consent was obtained from each subject.Results:At 1, 3 and 6 months after surgery, the central, superior, superior nasal, nasal, inferior nasal, inferior, inferior temporal, temporal and superior temporal ΔCET were significantly smaller in FS-LASIK Xtra group than in FS-LASIK group (all at P<0.05). In FS-LASIK Xtra group, 6-month postoperative central, superior, superior nasal, inferior and inferior temporal ΔCET were significantly larger than those at 1 month after surgery, and 3- and 6-month postoperative temporal ΔCET were significantly larger than that at 1 month after surgery, and 6-month postoperative superior temporal ΔCET was significantly larger than those at 1 and 3 months after surgery (all at P<0.05). In FS-LASIK group, 3- and 6-month postoperative central, superior, inferior and inferior temporal ΔCET were significantly larger than those at 1 month after surgery, and 6-month postoperative superior nasal ΔCET was significantly larger than that at 3 months after surgery, and 6-month postoperative nasal, inferior nasal, temporal, superior temporal ΔCET were significantly larger than those at 1 and 3 months after surgery (all at P<0.05). There was no significant difference in vertical trefoil, vertical and horizontal coma changes at different time points after surgery between both groups (vertical trefoil: χ2group=4.27, P=0.118; χ2time=0.01, P>0.05.vertical coma: χ2group=5.74, P=0.057; χ2time=0.08, P=0.957.horizontal coma: χ2group=3.97, P=0.137; χ2time=0.51, P=0.773). The tilted trefoil changes at 1, 3 and 6 months after surgery of FS-LASIK Xtra group were significantly larger than those of FS-LASIK group (all at P<0.05). The 6-month spherical aberration change in FS-LASIK Xtra group was significantly higher than that at 1 month after surgery, and the 6-month spherical aberration change in FS-LASIK group was significantly higher than that at 1 and 3 months after surgery (all at P<0.05). The 6-month total HOA change in FS-LASIK group was significantly lower than that at 1 and 3 months after surgery (all at P<0.05). In FS-LASIK group, central corneal ΔCET was weakly positively correlated with spherical aberration at 1 and 6 months after surgery ( rs=0.257, P=0.008; rs=0.244, P=0.012), and was weakly positively correlated with total HOA ( rs=0.253, P=0.009; rs=0.279, P=0.004). Conclusions:The postoperative ΔCET after FS-LASIK Xtra is smaller than that after FS-LASIK, but the homogeneity of ΔCET in each region is similar between the two groups.The changes in corneal HOA after surgery are similar in both groups, and there is a certain association between the overall epithelial distribution and corneal aberration.

Comparison of early postoperative visual quality between SMILE and SPT-TransPRK / 中华实验眼科杂志

Objective:To investigate the differences and changes in early postoperative visual quality after small incision lenticule extraction (SMILE) and smart pulse technology-assisted transepithelial photorefractive keratectomy (SPT-TransPRK).Methods:A cohort study was performed.A total of 92 patients (92 eyes) who underwent corneal laser refractive surgery were enrolled in Dalian Third People's Hospital Affiliated to Dalian Medical University from February 2021 to May 2021.The data from the right eye were collected for analysis.The patients were divided into SMILE group (40 patients, 40 eyes) and SPT-TransPRK group (52 patients, 52 eyes). Preoperative, 1- and 3-month postoperative visual acuity were measured to calculate the effectiveness, which was defined as the ratio of postoperative uncorrected visual acuity (UCVA) to preoperative best corrected visual acuity.Refraction was measured by an AR-1 autorefractor.Corneal higher-order aberration (HOA) including total HOA, spherical aberration and coma was measured by Sirius corneal topographer.Objective scatter index (OSI), modulation transfer function cut-off frequency (MTF cut-off), Strehl ratio (SR), simulated contrast visual acuity VA100 (day), VA20 (dusk) and VA9 (night) were measured via OQAS II visual quality analysis system.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of the Dalian Third People's Hospital Affiliated to Dalian Medical University (No.2019-KT-010). Written informed consent was obtained from each subject.Results:There was no significant difference in 3-month postoperative UCVA and effectiveness between the two groups ( Z=0.880, P=0.380; t=0.920, P=0.058). Patients in SPT-TransPRK group showed mild hyperopia 3 months after surgery.Preoperative, 1- and 3-month postoperative total corneal HOA was (0.47±0.18), (0.70±0.22) and (0.74±0.19)μm in SMILE group, and (0.40±0.14), (0.98±0.35) and (0.94±0.22)μm in SPT-TransPRK group respectively, showing statistically significant differences ( Fgroup=13.851, P=0.001; Ftime=29.960, P<0.001). Preoperative, 1- and 3-month postoperative spherical aberration was (-0.20±0.09), (-0.44±0.14) and (-0.44±0.15)μm in SMILE group, and (-0.20±0.10), (-0.71±0.23) and (-0.75±0.20)μm in SPT-TransPRK group respectively, showing statistically significant differences ( Fgroup=31.037, P<0.001; Ftime=48.005, P<0.001). The postoperative total corneal HOA and spherical aberration were increased in both groups compared with before surgery, with statistically significant differences (all at P<0.05). The 1- and 3-month postoperative total corneal HOA and spherical aberrations were smaller in SMILE group than in SPT-TransPRK group, and the differences were statistically significant (all at P<0.05). The 1- and 3-month postoperative coma were increased in both groups compared with before surgery, showing statistically significant differences (all at P<0.05). In SMILE group, 1-month postoperative OSI was higher and 1-month postoperative MTF cut-off, SR, and VA9 were lower than those before surgery, and 3-month postoperative OSI was higher and 3-month postoperative SR and VA9 were lower than those before surgery, showing statistically significant differences (all at P<0.05). In SPT-TransPRK group, 1-month postoperative OSI was higher and 1-month postoperative MTF cut-off, SR, VA100, VA20, and VA9 were lower than those before surgery, showing statistically significant differences (all at P<0.05). There was no significant difference in OSI, MTF cut-off, SR, VA100, VA20, and VA9 between 3 months postoperatively and before surgery in the SPT-TransPRK group (all at P>0.05). There was no significant difference in coma, OSI, MTF cut-off, SR, VA100, VA20, and VA9 between two groups (all at P>0.05). Conclusions:Both SMILE and SPT-TransPRK are effective methods for correcting myopia and they have comparable visual quality.Compared with SPT-TransPRK, corneal total HOA and spherical aberration are smaller after SMILE.

Comparison of corneal higher order aberration after femtosecond laser-assisted laser in situ keratomileusis and small incision lenticule extraction / 中华实验眼科杂志

Objective:To analyze and compare the corneal higher order aberration (HOA) after femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE).Methods:A non-randomized controlled study was conducted.Sixty myopic patients (60 eyes) who underwent FS-LASIK or SMILE correction at Shandong Eye Hospital from April 2018 to January 2020 were enrolled and the data from the right eye were collected for analysis.Thirty cases (30 eyes) who received FS-LASIK in FS-LASIK group and 30 cases (30 eyes) who received SMILE in SMILE group had a preoperative equivalent spherical diopter of (-5.36±1.11)D and (-4.93±1.03)D, respectively.The HOA of the 6-mm anterior surface, posterior surface, and whole cornea were measured before surgery and at 1, 3, 6, and 12 months after surgery using Pentacam.The root mean square values (μm) of total corneal HOA, spherical aberration, coma and trefoil were obtained.Differences in the above root mean square values at different time points were compared between the two groups.The study protocol adhered to the Declaration of Helsinki and was approved by the Ethics Committee of Shandong Eye Hospital (No.SDSYKYY20180306). Written informed consent was obtained from each subject.Results:The preoperative and 1-, 3-, 6-, 12-month postoperative total HOA of the anterior corneal surface were (0.428±0.126), (0.775±0.169), (0.811±0.194), (0.759±0.214), (0.704±0.199)μm in the FS-LASIK group and (0.409±0.094), (0.656±0.148), (0.681±0.161), (0.668±0.175), (0.648±0.160)μm in the SMILE group, with a significant overall difference ( Fgroup=5.652, P=0.024; Ftime=107.169, P<0.01). Compared with SMILE group, the postoperative total HOA of anterior corneal surface and spherical aberration at different time points were increased in FS-LASIK group, showing statistically significant differences (all at P<0.05). Compared with before surgery, the postoperative total HOA of the anterior corneal surface and spherical aberration at different time points were increased in both groups, showing statistically significant differences (all at P<0.05). In the two groups, the 6- and 12-month postoperative total HOA of the anterior corneal surface were reduced in comparison with the 3-month postoperative ones of the anterior corneal surface, and the 12-month postoperative spherical aberrations of the anterior corneal surface were significantly reduced in comparison with the 1- and 3-month postoperative ones of the anterior corneal surface, showing statistically significant differences (all at P<0.05). There were significant differences in the coma and trefoil of the anterior corneal surface between before and after the operation (coma: Ftime=47.848, P<0.01; trefoil: Ftime=2.497, P=0.046). Compared with before surgery, the postoperative coma was significantly increased in the two groups (all at P<0.05). There were significant differences in total corneal HOA and spherical aberration at different postoperative time points between the two groups (total HOA: Fgroup=8.093, P=0.008; Ftime=125.019, P<0.01.spherical aberration: Fgroup=4.771, P=0.037; Ftime=34.033, P<0.01). Compared with SMILE group, the total corneal HOA and spherical aberration were significantly increased in FS-LASIK group at different postoperative time points (all at P<0.05). Compared with before surgery, postoperative total HOA of the anterior corneal surface and spherical aberration at different postoperative time points were significantly increased in both groups (all at P<0.05). In both groups, the 12-month postoperative corneal spherical aberration was significantly reduced in comparison with the 1- and 3-month postoperative ones (all at P<0.05). There was a significant difference in coma between before and after surgery ( Ftime=30.829, P<0.01). Compared with before surgery, the postoperative coma was significantly increased at different time points in both groups (all at P<0.05). Conclusions:Both FS-LASIK and SMILE increase the HOA of the anterior corneal surface and the whole cornea.Compared with FS-LASIK, SMILE introduces less HOA of the anterior corneal surface and the whole cornea as well as spherical aberrations.

Aumento das aberrações de alta ordem pós-ceratectomia fotorrefrativa guiada por frente de onda: relato de caso / Increased high-order aberrations after wavefront-guided photorefractive keratectomy: case report

RESUMO Ao remodelar a córnea usando um perfil de ablação individualizado para cada olho obtido por meio de aberrometria de frente de onda, o tratamento guiado por frente de onda tenta reduzir aberrações preexistentes e induzidas cirurgicamente, minimizando as aberrações de alta ordem (HOAs) visualmente significativas. No entanto, o aumento de HOA ainda é uma preocupação, mesmo com ablações personalizadas. Na cirurgia refrativa a laser miópica, como o feixe de laser entra na periferia, algumas partes são refletidas, e o feixe circular se torna elíptico, resultando em diminuição na eficácia da energia do laser. A subablação da córnea periférica pode ser induzida por esses fatores que aumentam a HOA, especialmente a aberração esférica. Este relato tem por finalidade mostrar uma paciente alto míope submetida à PRK guiada por frente de onda que evoluiu com aumento das HOAs.

ABSTRACT By reshaping the cornea using an individualized ablation profile for each eye obtained through wavefront aberrometry, wavefront guided treatment attempts to reduce preexisting and surgically induced aberrations while minimizing visually significant higher-order aberrations (HOAs). However, HOA enhancement is still a concern, even with custom ablations. In the myopic laser refractive surgery, as the laser beam enters the periphery, some parts are reflected, and the circular beam becomes elliptical, resulting in a decrease in the effectiveness of the laser energy. Peripheral corneal subablation can be induced by these factors that increase HOA, especially spherical aberration. This report aims to show a high myopic patient undergoing wavefront-guided PRK, who evolved with an increase in HOAs.

Influence and significance of angle Kappa on total ocular aberrations before and after SMILE surgery / 中华实验眼科杂志

Objective:To investigate the influence of angle Kappa on total high-order aberration (HOA) before and after small incision lenticule extraction (SMILE).Methods:An observational case series study was conducted.Right eyes of 98 patients with myopia and myopic astigmatism who underwent SMILE surgery at Tianjin Eye Hospital from April 2015 to May 2016 were selected.Uncorrected visual acuity (UCVA), spherical diopter and cylindrical diopter under cycloplegic condition were examined before the surgery and at l and 3 months postoperatively.The chord distance of angle Kappa was measured by Pentacam topography.Wavefront aberrations were measured by WaveScan aberrometer.Pre- and postoperative UCVA, refractive status and each HOA were analyzed.The relationship between angle Kappa and each HOA was analyzed by Pearson correlation.This study adhered to the Declaration of Helsinki.The study protocol was approved by an Ethics Committee of Tianjin Eye Hospital (No.TJYYLL-2017-17). Written informed consent was obtained from each subject.Results:The preoperative, postoperative 1-month and postoperative 3-month UCVA (LogMAR) were 0.06±0.23, -0.03±0.07 and -0.05±0.07, respectively, showing a statistically significant difference ( F=779.330, P<0.001). There were statistically significant differences in spherical diopter, cylinder diopter and spherical equivalent (SE) between before and after operation ( F=1 107.811, 127.786, 1 191.266; all at P<0.001), and the postoperative spherical diopter, cylinder diopter and SE were significantly lower than those before surgery (all at P<0.001). At 6-mm pupil diameter, significant differences were found between postoperative total HOA, spherical aberration, coma, the third-order aberration (S3), fourth-order aberration (S4), fifth-order aberration (S5) and sixth-order aberration (S6) and the preoperative values ( F=75.915, 78.231, 66.186, 64.521, 97.161, 36.623, 28.852; all at P<0.001). The postoperative 1- and 3-month total HOA, spherical aberration, coma, S3, S4, S5 and S6 were significantly increased in comparison with those before surgery (all at P<0.05). There was a positive correlation between angle Kappa and total HOA, coma and S3 at 1 and 3 months after surgery (total HOA: r=0.357, 0.363; both at P<0.001.coma: r=0.310, 0.341; both at P<0.01.S3∶ r=0.343, 0.371; both at P<0.01). Significant differences were found in preoperative, postoperative 1-month and 3-month total HOA, coma and S3 between groups with different angle Kappa ( Fgroup=3.363, 4.277, 4.029; all at P<0.05). The postoperative total HOA, coma and S3 of the larger angle Kappa group were greater than those of the smaller angle Kappa group, with statistically significant differences between them (all at P<0.05). Conclusions:A larger angle Kappa may induce HOAs in SMILE surgery.

Progress of application of adaptive optics in ophthalmology / 中华实验眼科杂志

Adaptive optics (AO) can measure and correct wavefront aberrations in real time, which enables the optical system to adapt to external changes and maintain excellent optical performance, and has been gradually paid attention in the field of ophthalmology.AO technology can carry out optometry according to wavefront aberrations to improve the efficiency and accuracy of subjective and objective refraction, eliminate the influence of ocular aberrations on retinal imaging, provide more accurate data for the evaluation of optic nerve function, improve the effectiveness of visual perception training and provide vision care and treatment for special people, as well as simulate and predict postoperative visual outcome and give personalized schemes for refractive surgery and intraocular lens implantation.Moreover, AO combined with optical coherence tomography, optical scanning laser ophthalmoscope, and confocal scanning laser ophthalmoscope, can realize fundus imaging and retinal vascular imaging in real time, provide better sensitivity and resolution of retinal detection, distinguish fine details of retinal vessels and cone cells, and characterize retinal pigment epithelium topology and deformation, the application of which in posterior segment laser surgery, glaucoma diagnosis and follow-up, color blindness and retinal physiological activity research has been attracting attention.In this article, the principle and application of AO in ophthalmology were briefly reviewed.

Clinical Outcomes of Small Incision Lenticule Extraction in Myopia: Study of Vector Parameters and Corneal Aberrations

Comparison of Corneal Astigmatism and Higher-order Aberrations between Color Light-emitting Diode Topographer and Scheimpflug Imager

PURPOSE: To compare corneal astigmatism, keratometry and corneal higher order aberrations between the light emitting diode corneal topography analyzer and Scheimpflug Imager. METHODS: This prospective study involved 45 patients (45 eyes) who visited Seoul St. Mary's hospital before cataract surgery from June 7, 2017, to August 2, 2017. For each eye, keratometry, astigmatism and its axis of cornea, higher-order aberrations were evaluated with a Scheimpflug Imager (Pentacam HR®, Oculus, Wetzlar, Germany) and a color-LED corneal topographer (Cassini®, i-Optics, Den Haag, The Netherlands). RESULTS: Astigmatism magnitude measured using Cassini® and Pentacam® showed no statistically differences but anterior and total astigmatic axes were significantly different, as measured by the two devices (p < 0.05). Anterior and total mean keratometry were statistically significantly different, as measured by the two devices (p < 0.05). J0 and J45 vectors of anterior and total cornea were statistically different (p < 0.05). In addition, Cassini® and Pentacam® showed discrepancies between total corneal astigmatism, total J0 and J45 vectors. Corneal anterior spherical aberration, vertical and horizontal coma, and oblique and horizontal trefoil aberrations were not statistically different between the two devices. CONCLUSIONS: Astigmatic axes obtained from the two devices based on different principles showed statistically significant differences. Astigmatism magnitude was not statistically different but showed a discrepancy between the two devices.

Effect of corneal biomechanical properties on surgically-induced astigmatism and higher-order aberrations after cataract surgery / Efeito das propriedades biomecânicas da córnea no astigmatismo induzido cirurgicamente e nas aberrações de alta ordem após a cirurgia de catarata

ABSTRACT Purpose: To investigate the relationship between biomechanical properties of the cornea and postoperative refractive changes in patients with low-level astigmatism after cataract surgery. Methods: This prospective study recruited patients undergoing cataract surgery involving 2.8-mm superior incisions. Biomechanical properties of the cornea were evaluated preoperatively using the Ocular Response Analyzer, and corneal profiles were evaluated using a Scheimpflug system (Pentacam HR). Topographic astigmatism, total corneal aberrations (TCA) and higher-order corneal aberrations (HOCA) analyses were performed preoperatively and during 1- and 3-month postoperative exams. The incidences of surgically-induced astigmatism (SIA) and HOCAs were calculated using vector analyses. Associations of the preoperative biomechanical properties of the cornea with SIA and HOCAs were evaluated. Results: This study included 28 eyes of 28 patients. The preoperative corneal hysteresis (CH) was 8.68 ± 1.86 mmHg, and the corneal resistance factor (CRF) was 8.66 ± 1.61 mmHg. At the 1-month postoperative evaluation, significant changes were observed in HOCAs (p=0.023), TCAs (p=0.05), astigmatism (p=0.02), and trefoil (p=0.033); in contrast, differences in coma (p=0.386) and spherical aberration (SA) were not significant (p=0.947). At the 3-month visit, significant changes were only observed in TCAs (p=0.02) and HOCAs (p=0.012). No relationships between the preoperative corneal hysteresis and corneal resistance factor and postoperative SIA and HOCA were identified, other than a positive correlation between the 3-month postoperative incidence of corneal hysteresis and spherical aberration. Conclusions: Despite the observed lack of relationships of preoperative biomechanical properties of the cornea with SIA and postoperative aberrations (except for SA), further studies involving larger patient groups are needed to explore the unexpected refractive deviations after cataract surgery.

RESUMO Objetivo: Investigar a relação entre as propriedades biomecânicas da córnea e as mudanças refrativas pós-operatórias em pacientes com baixa astigmatismo após a cirurgia de catarata. Método: Neste estudo prospectivo, recrutamos os pacientes submetidos a cirurgia de catarata com incisões superiores de 2,8 mm. As propriedades biomecânicas da córnea foram avaliadas no pré-operatório pelo Ocular Response Analyzer (ORA, Reichert, EUA) e o perfil corneano foi avaliado por um sistema Scheimpflug (Pentacam HR, Oculus Optikgeräte, GmbH). As avaliações do astigmatismo topográfico e das aberrações corneanas de alta ordem (HOCA) foram feitas no pré-operatório e no 1º e 3º mês pós-operatório. O astigmatismo induzido cirurgicamente (SIA) e aberrações corneanas de alta ordem foram calculados pela análise vetorial. Associações das propriedades biomecânicas da córnea no pré-operatório com astigmatismo induzido cirurgicamente e aberrações corneanas de alta ordem foram avaliadas. Resultados: O estudo foi realizado em 28 olhos de 28 pacientes. A histerese corneana (CH) pré-operatória foi 8,68 ± 1,86 mmHg, e o fator de resistência da córnea (CRF) foi de 8,66 ± 1,61 mmHg. No pós-operatório de 1 mês houve mudanças significativas aberrações corneanas de alta ordem (p=0,023), aberração total (p=0,05), astigmatismo (p=0,02) e trifóglio (p=0,033), mas as diferenças em coma (p=0,386) e aberração esférica (SA) foram insignificantes (p=0,947). No terceiro mês, a única mudança significativa foi em RMS total (p=0,02) e aberração total (p=0,012). Não houve relação entre histerese corneana e o fator de resistência da córnea pré-operatórios e astigmatismo induzido cirurgicamente e aberrações corneanas de alta ordem pós-operatórios, além de uma correlação positiva entre o histerese corneana e o aberração esférica do 3º mês pós-operatório. Conclusões: Apesar de não haver relação entre as propriedades biomecânicas pré-operatórias da córnea e astigmatismo induzido cirurgicamente e aberrações (exceto SA) após a cirurgia em nosso estudo, são necessários mais estudos com grupos de pacientes maiores de explicar os erros refrativos inesperados após a cirurgia de catarata.

Higher Order Aberration and Astigmatism in Children with Hyperopic Amblyopia

PURPOSE: To investigate the changes in corneal higher-order aberration (HOA) during amblyopia treatment and the correlation between HOA and astigmatism in hyperopic amblyopia children. METHODS: In this retrospective study, a total of 72 eyes from 72 patients ranging in age from 38 to 161 months were included. Patients were divided into two groups based on the degree of astigmatism. Corneal HOA was measured using a KR-1W aberrometer at the initial visit and at 3-, 6-, and 12-month follow-ups. Correlation analysis was performed to assess the association between HOA and astigmatism. RESULTS: A total of 72 patients were enrolled in this study, 37 of which were classified as belonging to the higher astigmatism group, while 35 were assigned to the lower astigmatism group. There was a statistically significant difference in success rate between the higher and lower astigmatism groups. In both groups, all corneal HOAs were significantly reduced during amblyopia treatment. When comparing the two groups, a significant difference in coma HOA at the 12-month follow-up was detected (p = 0.043). In the Pearson correlation test, coma HOA at the 12-month follow-up demonstrated a statistically significant correlation with astigmatism and a stronger correlation with astigmatism in the higher astigmatism group than in the lower astigmatism group (coefficient values, 0.383 and 0.284 as well as p = 0.021 and p = 0.038, respectively). CONCLUSIONS: HOA, particularly coma HOA, correlated with astigmatism and could exert effects in cases involving hyperopic amblyopia.

Evaluation of possible factors affecting contrast sensitivity function in patients with primary Sjögren’s syndrome / A avaliação dos possíveis fatores que afetam a função de sensibilidade ao contraste em pacientes com síndrome de Sjögren primária

ABSTRACT Purpose: The contrast sensitivity (CS) function in patients with primary Sjögren’s syndrome (pSS) may be impaired either frequently as a result of dry eye diseases or rarely as a result of optic neuropathy. In this study, we aimed to evaluate the CS function in pSS patients as well as to assess corneal aberrations and thickness of the peripapillary retinal nerve fiber layer (pRNFL). Methods: Fourteen eyes of 14 pSS patients (pSS group) and 14 eyes of 14 healthy participants (control group) were subjected to assessment of CS at the spatial frequencies of 1.5, 3.0, 6.0, 12, and 18 cycles/degree (cpd) using a functional visual acuity contrast test (FACT); measurement of corneal high-order aberrations (HOAs) in terms of coma-like, spherical-like, and total HOAs using Scheimpflug corneal topography; and measurement of the thickness of both the macular ganglion cell-inner plexiform layer (mGCIPL) and pRNFL in all quadrants using optical coherence tomography. None of the participants were under treatment with artificial tears. Results: The results of the CS test did not differ between the 2 groups at all spatial frequencies (p>0.05). In addition, there were no statistically significant differences between the 2 groups in terms of corneal HOAs (p>0.05) and thickness of mGCIPL (p>0.05). However, among all quadrants, only the inferior quadrant of pRNFL in pSS patients was statistically significantly thinner than that in the healthy participants (p=0.04). Conclusions: The CS function in pSS patients can be maintained with normal thickness of both pRNFL and mGCIPL and with lack of increased corneal HOAs, which may be present even in the absence of artificial tear usage. .

RESUMO Objetivo: A função de sensibilidade ao contraste em pacientes com síndrome de Sjögren primário (pSS) pode ser prejudicada, quer frequentemente como resultado de doenças do olho seco, ou mais raramente como um resultado de neuropatia óptica. Neste estudo, objetivamos avaliar a função de sensibilidade ao contraste de pacientes com pSS, além da avaliação das aberrações da córnea e a espessura da camada de fibras nervosas da retina (pRNFL). Métodos: Catorze olhos de 14 pacientes com pSS e 14 olhos de 14 participantes saudáveis foram submetidos, respectivamente, à avaliação do teste de sensibilidade aos contrastes (CS) nas frequências espaciais de 1,5, 3,0, 6,0, 12 e 18 ciclos/grau (cpd), utilizando teste de contraste acuidade visual funcional (FACT); a medida das aberrações de alta ordem da córnea (HOAs) em termos de coma, aberrações esféricas e aberrações totais, utilizando topografia corneana por Scheimpflug; e medida de espessura da camada de macular de células ganglionares plexiforme interna (mGCIPL) e a espessura de pRNFL em todos os quadrantes usando tomografia de coerência óptica. Nenhum dos participantes estava sob tratamento com lágrimas artificiais. Resultados: O teste CS em pacientes pSS não diferiu do que o teste CS em participantes saudáveis em todas as frequências espaciais (p>0,05). Não houve também nenhuma diferença estatisticamente significativa entre os dois grupos em termos de HOAs da córnea (p>0,05), e espessura de mGCIPL (p>0,05). No entanto, entre todos os quadrantes, apenas o quadrante inferior da pRNFL em pacientes pSS foi significativamente mais fino que o quadrante inferior da pRNFL em participantes saudáveis (p=0,04). Conclusões: A função de CS em doentes com pSS pode ser mantida em condições de ambas as espessuras normais de pRNFL e mGCIPL, assim como nas condições de falta de aumento HOAs da córnea, que pode ser mantida, mesmo na ausência do uso de lágrimas artificiais. .

Change of higher order aberration after 2 mm micro-incision SMILE in myopia / 中华实验眼科杂志

Background Small incision lenticule extraction (SMILE) is increasingly used for myopia.However,the size of the incision varied in different operators.The influence of 2 mm micro-incision SMILE on postoperative diopter and aberrations is not clear yet.Objective The aim of the current study was to perform a clinical analysis of the efficacy,safety,stability and predictability of 2 mm micro-incision SMILE and investigate the influence of preoperative sphere and cylinder power on postoperative aberrations.Methods A serial cases observational study was carried out under the approval of Ethic Committee of Tianjin Eye Hospital and informed consent of each patient.Fifty-five eyes of 31 subjects with myopia and myopic astigmatism were enrolled in this study in Tianjin Eye Hospital from January to April 2013 and a 2 mm micro-incision SMILE was performed on the eyes.Follow-up visits were performed at 1 week,1 month and 6 months after operation.Uncorrected visual acuity (UCVA),best corrected visual acuity (BCVA),manifest and cycloplegic refraction were examined at each postoperative time points to evaluate the efficacy,safety,stability and predictability of 2 mm micro-incision SMILE.Wave-front aberrations were measured by WaveScan aberrometer.Repeated measurement analysis of variance was used for the comparison of the differences of aberrations before and after the surgery.And the differences between various follow-up visits were compared with LSD-t test.The relationship between preoperative sphere or cylinder power and aberrations postoperatively were analyzed by Spearman rank correlation.Results At 1 week,1 month and 6 months postoperatively,the effective index was 1.2,and the safety indexes were 1.2,1.2 and 1.5 respectively.The spherical equivalent remained 0.00 D at each postoperative time point.And 96.4％ and 97.8％ of eyes were within ±0.5 D of intend correction and 100％ were within ± 1.0 D of the intend correction at 1 month and 6 months postoperatively.Vertical coma (Z7) and spherical aberration (Z12) were significantly raised at 1 week,1 month and 6 months after surgery compared with the values preoperatively (Z7:t =9.668,10.607,9.772,all at P ＜ 0.001 ;Z 12:t =-6.227,-6.923,-7.441,all at P＜0.001).The Zernike coefficients were relatively symmetrical between various time points postoperatively (all at P＞0.05).Third-order to sixth-order aberrations and higher order abberration (HOA) showed significant increase at various time points after the surgery compared with the values before surgery (all at P＜0.05),and no significant differences were seen between various follow-up visits (all at P＞0.05).Positive correlations were found between preoperative sphere and S3,S4 and HOA at 1 week,1 month and 6 months postoperatively (P＜0.05).Negative correlations were found between preoperative cylinder and S3,S4 and HOA at postoperatively various time points (all at P＜0.05).In addition,significant positive correlations were seen between Z7 and preoperative cylinder as well as between Z12 and sphere preoperatively,and negative correlations also were observed between Z7 and preoperative sphere as well as between Z12 and cylinder preoperatively at each follow-up visits(all at P＜0.05).Conclusions SMILE with 2 mm micro-incision is a safe,effective,stable and predictable procedure for myopic and myopic astigmatism eyes.The aberrations and Zernike terms remain stable after surgery until 6 months although these parameters present elevation to a certain extent.Preoperative SE and astigmatism power affect postoperative aberrations.

Visual optics under the wavefront perspective / Óptica visual sob a perspectiva das frentes de onda

Some intriguing concepts of visual optics cannot be explained by ray tracing. However, they can be clarified using wavefront formalism. Its main advantage is in the use of the concept of vergence, which is very helpful in interpreting the optical phenomena involved in the neutralization of the ametropias. In this line of thinking, the major role of a lens is in the creation of a new light source (the image point) that orientates the refracted waves. Once the nature and position of this source is known, one can easily predict the behavior of the wavefronts. The formalism also allows for an easier understanding on how wavefronts relate to light rays and on how algebraic signs are assigned to optical distances.

Alguns conceitos intrigantes da óptica visual não podem ser explicados pelo traçado dos raios luminosos. Entretanto, eles podem ser esclarecidos através do formalismo da frente de onda. A vantagem do mesmo está no uso do conceito de vergência, que facilita o entendimento dos fenômenos ópticos envolvidos na neutralização das ametropias. Nessa linha de raciocínio, a principal função de uma lente é o de criar de uma nova fonte de luz - o ponto de imagem - que orienta as ondas refratadas. Conhecendo-se a natureza e a posição dessa fonte pode-se facilmente prever o comportamento das frentes de onda. Este formalismo também ajuda a compreensão de como as frentes de onda se relacionam com os raios de luz e como os sinais algébricos são atribuídos às distâncias ópticas.

Comparison of wavefront aberrations under cycloplegic, scotopic and photopic conditions using WaveScan / Comparação de aberrações de frente de onda sob cicloplegia, condições escotópica e fotópica usando WaveScan

PURPOSE: To evaluate the differences of wavefront aberrations under cycloplegic, scotopic and photopic conditions. METHODS: A total of 174 eyes of 105 patients were measured using the wavefront sensor (WaveScan® 3.62) under different pupil conditions: cycloplegic 8.58 ± 0.54 mm (6.4 mm - 9.5 mm), scotopic 7.53 ± 0.69 mm (5.7 mm - 9.1 mm) and photopic 6.08 ± 1.14 mm (4.1 mm - 8.8 mm). The pupil diameter, standard Zernike coefficients, root mean square of higher-order aberrations and dominant aberrations were compared between cycloplegic and scotopic conditions, and between scotopic and photopic conditions. RESULTS: The pupil diameter was 7.53 ± 0.69 mm under the scotopic condition, which reached the requirement of about 6.5 mm optical zone design in the wavefront-guided surgery and prevented measurement error due to the pupil centroid shift caused by mydriatics. Pharmacological pupil dilation induced increase of standard Zernike coefficients Z3-3, Z4(0) and Z5-5. The higher-order aberrations, third-order aberration, fourth-order aberration, fifth-order aberration, sixth-order aberration, and spherical aberration increased statistically significantly, compared to the scotopic condition (P<0.010). When the scotopic condition shifted to the photopic condition, the standard Zernike coefficients Z4(0), Z4², Z6-4, Z6-2, Z6² decreased and all the higher-order aberrations decreased statistically significantly (P<0.010), demonstrating that accommodative miosis can significantly improve vision under the photopic condition. Under the three conditions, the vertical coma aberration appears the most frequently within the dominant aberrations without significant effect by pupil size variance, and the proportion of spherical aberrations decreased with the decrease of the pupil size. CONCLUSIONS: The wavefront aberrations are significantly different under cycloplegic, scotopic and photopic conditions. Using the wavefront sensor (VISX WaveScan) to measure scotopic wavefront aberrations is feasible for the wavefront-guided refractive surgery.

OBJETIVO: Avaliar as diferenças de aberrações de frente de onda, em diferentes condições pupilares: sob cicloplegia, escotópica e fotópica. MÉTODOS: Um total de 174 olhos de 105 pacientes foram avaliados utilizando o sensor de frente de onda (WaveScan® 3.62) em diferentes condições pupilares: sob cicloplegia 8,58 ± 0,54 mm (6.4 mm-9.5 mm), escotópica 7,53 ± 0,69 mm (5,7 mm - 9,1 mm) e fotópica 6,08 ± 1,14 mm (4,1 mm - 8,8 mm). Diâmetro da pupila, coeficientes de Zernike, RMS ("Root Mean Square") das aberrações de alta ordem e as aberrações dominantes foram comparados entre as condições sob cicloplegia e escotópica, e entre as condições escotópica e fotópica. RESULTADOS: O diâmetro da pupila foi 7,53 ± 0.69 mm sob a condição escotópica e atingiu a exigência de cerca de 6,5 mm de zona óptica na cirurgia baseada em análise de frentes de ondas, evitando erros de medição consequentes à mudança de centroide pupilar provocada por midriáticos. A dilatação farmacológica da pupila induziu aumento dos coeficientes de Zernike Z3-3, Z4(0) e Z5-5. As aberrações de mais alta ordem (terceira, quarta, quinta e sexta ordem) e a aberração esférica aumentaram de forma estatisticamente significativa, em comparação com a condição escotópica (P<0,010). Quando a condição escotópica se mudou para a condição fotópica, os coeficientes de Zernike Z4(0), Z4², Z6-4, Z6-2, Z6² e todas as aberrações de alta ordem diminuíram de forma estatisticamente significativa (P<0,010), demonstrando que a miose acomodativa pode significativamente melhorar a visão sob a condição fotópica. Sob as três condições, a aberração coma vertical apareceu mais frequentemente dentro das aberrações dominantes, sem influência significativa da variação do tamanho da pupila, e a proporção de aberração esférica diminuiu com a diminuição do tamanho da pupila. CONCLUSÕES: As aberrações de frente de onda são significativamente diferentes sob cicloplegia, condições escotópica e fotópica. O uso do sensor de frentes de onda (VISX WaveScan) para medir as aberrações de frente de onda escotópicas é uma opção viável para a cirurgia refrativa baseada em análise de frentes de onda.

Impacto da análise do 'wavefront' na refratometria de pacientes com ceratocone / Impact of the wavefront analysis in refraction of keratoconus patients

OBJETIVO: Verificar se a aberrometria ocular total (análise da frente de onda ou 'wavefront') possibilita melhora na acuidade visual corrigida (AVc) com lentes esfero-cilíndricas, obtida com a refratometria manifesta em casos de ceratocone com algum grau de intolerância ao uso de lentes de contato. MÉTODOS: Os prontuários de 46 pacientes (89 olhos), referidos com diagnóstico de ceratocone e intolerantes ao uso de lentes de contato, submetidos ao exame de aberrometria ocular total seguido de refração manifesta, foram estudados de forma retrospectiva. A AVc (logMAR) com a correção existente antes do exame foi comparada com a obtida com a nova refração manifesta, realizada considerando-se os dados objetivos da aberrometria. O teste não-paramétrico de Wilcoxon para amostras pareadas foi utilizado para verificação de diferenças estatisticamente significantes na AVc. RESULTADOS: Houve uma melhora estatisticamente significante na AVc com a nova refração manifesta (p<0,0001). A AVc média passou de 0,37 ou 20/47 (variando entre 1,3 e 0; desvio padrão[DP]=0,25) com a refração prévia para 0,23 ou 20/34 (variando entre 1 e 0,1; DP=0,21). Cinquenta e dois olhos (58,4 por cento) de 28 pacientes apresentaram melhora na AVc com a nova refração. A melhora média foi de 0,13 logMAR (1,3 linhas na tabela de Snellen), variando entre nula e 0,6 (6 linhas), com desvio padrão de 0,16. Oito pacientes apresentaram anisometropia significativa que limitou a prescrição de óculos em um dos olhos. CONCLUSÃO: A aberrometria facilitou a refratometria, determinando melhora significativa na acuidade visual corrigida com as lentes esfero-cilíndricas de pacientes com ceratocone intolerantes ao uso de lentes de contato. A anisometropia foi um fator limitante na prescrição de óculos.

OBJECTIVE: To verify if the total ocular aberrometry (wavefront analysis) facilitates manifest refraction and improvement in best spectacle distance corrected visual acuity (BSCDVA) with sphero-cylindrical lenses, in keratoconus cases with some degree of contact lenses intolerance. METHODS: Retrospective chart review of 46 patients (89 eyes) referred with keratoconus and contact lenses intolerance was performed. Ocular aberrometry with ray tracing was followed by manifest refraction. BSCDVA (logMAR) with the previous correction was compared with the one obtained based on the wavefront autorefraction. The nonparametric test of Wilcoxon for paired samples was used to test statistically significant differences in BSCDVA. RESULTS: There was a statistically significant improvement in BSCDVA with the new manifest refraction (p <0,0001). The average BSCDVA changed from 0,37 or 20/47 (varying between 1,3 and 0; standard deviation [SD] = 0,25) with previous refraction to 0,23 or 20/34 (varying between 1 and 0,1; SD = 0,21). 52 eyes (58,4 percent) of 28 patients showed improvement in BSCDVA with the new refraction. The average improvement was 0,13 logMAR (1,3 lines on Snellen chart), varying between zero and 0,6 (6 lines), with standard deviation of 0,16. Eight patients had significant anisometropia that limited the prescription of glasses. CONCLUSION: Aberrometry facilitated the refraction, determining significant improvement in visual acuity with sphero-cylindrical lenses in keratoconus patients intolerant to contact lenses. The anisometropia was a limiting factor in the prescription of glasses.

Impacto da análise do "wavefront" na refratometria de pacientes com ceratocone / Impact of the wavefront analysis in refraction of keratoconus patients

OBJETIVO: Verificar se a aberrometria ocular total (análise da frente de onda ou wavefront) possibilita a melhora na acuidade visual corrigida (AVc) com lentes esfero-cilíndricas, obtida com a refratometria manifesta em casos de ceratocone com algum grau de intolerância ao uso de lentes de contato. MÉTODOS: Os prontuários de 46 pacientes (89 olhos) referidos com diagnóstico de ceratocone e intolerantes ao uso de lentes de contato, submetidos ao exame de aberrometria ocular total seguido de refração manifesta, foram estudados de forma retrospectiva. A AVc (logMAR) com a correção existente antes do exame foi comparada com a obtida com a nova refração manifesta, realizada, considerando-se os dados objetivos da aberrometria. O teste não-paramétrico de Wilcoxon para amostras pareadas foi utilizado para verificação de diferenças estatisticamente significantes na AVc. RESULTADOS: Houve uma melhora estatisticamente significante na AVc com a nova refração manifesta (p<0,0001). A AVc média passou de 0,37 ou 20/47 (variando entre 1,3 e 0; desvio padrão[DP]=0,25) com a refração prévia para 0,23 ou 20/34 (variando entre 1 e 0,1; DP=0,21). 52 olhos (58,4 por cento) de 28 pacientes apresentaram melhora na AVc com a nova refração. A melhora média foi de 0,13 logMAR (1,3 linhas na tabela de Snellen), variando entre nula e 0,6 (6 linhas), com desvio padrão de 0,16. Oito pacientes apresentaram anisometropia significativa que limitou a prescrição de óculos em um dos olhos. CONCLUSÃO: A aberrometria facilitou a refratometria, determinando melhora significativa na acuidade visual corrigida com as lentes esfero-cilíndricas de pacientes com ceratocone intolerantes ao uso de lentes de contato. A anisometropia foi um fator limitante na prescrição de óculos.

OBJECTIVE: To verify if the total ocular aberrometry (wavefront analysis) facilitates manifest refraction and improvement in best spectacle distance corrected visual acuity (BSCDVA) with sphero-cylindrical lenses, in keratoconus cases with some degree of contact lenses intolerance. METHODS: Retrospective chart review of 46 patients (89 eyes) referred with keratoconus and contact lenses intolerance was performed. Ocular aberrometry with ray tracing was followed by manifest refraction. BSCDVA (logMAR) with the previous correction was compared with the one obtained based on the wavefront auto-refraction. The nonparametric test of Wilcoxon for paired samples was used to test statistically significant differences in BSCDVA. RESULTS: There was a statistically significant improvement in BSCDVA with the new manifest refraction (p <0,0001). The average BSCDVA changed from 0,37 or 20/47 (varying between 1,3 and 0; standard deviation [SD] = 0,25) with previous refraction to 0,23 or 20/34 (varying between 1 and 0,1; SD = 0,21). 52 eyes (58,4 percent) of 28 patients showed improvement in BSCDVA with the new refraction. The average improvement was 0,13 logMAR (1,3 lines on Snellen chart), varying between zero and 0,6 (6 lines), with standard deviation of 0,16. Eight patients had significant anisometropia that limited the prescription of glasses. CONCLUSION: Aberrometry facilitated the refraction, determining significant improvement in visual acuity with sphero-cylindrical lenses in keratoconus patients intolerant to contact lenses. The anisometropia was a limiting factor in the prescription of glasses.