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BACKGROUND: Visual impairment can cause balance problems. Therefore, visual impairment caused by an increase in corneal deviations can lead to sudden and unstable loads in the lower extremities. We aimed to investigate the possible relationship between low-energy meniscal injuries and corneal structural measures. METHODS: This prospective, observational study included individuals aged between 18-40 years with a normal body-mass index. The study group consisted of 54 patients with grade 2 or 3 meniscus injuries after low-energy activity. The control group consisted of 54 healthy individuals without any complaints in the knee joint. The corneal parameters of all participants were evaluated with a Scheimpflug corneal topography and specular microscopy device. Simulated keratometry (SimK), minimum central corneal thickness (MCCT), cylindrical diopter (ClyD), corneal volume (CVol) spheric aberrations (SphAbb), high-order aberration (HOA), coma values, and endothelial parameters were recorded. RESULTS: The research and control groups were similar in terms of age, body mass index, and gender distribution. There was no significant difference between the groups in the corneal SimK and CylD, parameters. However, HOA, Coma, SphAbb, and cell variability (Cv) values were significantly higher in the study group, and contrarily MCCT, CVol, and endothelial count (Cd) values were significantly lower. CONCLUSIONS: Our findings suggest that individuals with relatively lower MCCT values tend to develop meniscal damage after low-energy activity. Hence, the loss of corneal strength in these patients may be a sign of possible weakness in the meniscus. The HOA value above 0.26, the coma value above 0.16, and the SphAbb value above 0.1 may significantly increase the possible meniscus injury.

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PURPOSE: To evaluate the corneal topography and aberrometry and their changes following ptosis surgery in patients suffering from unilateral congenital blepharoptosis. METHODS: The study included 15 eyes of 15 patients with unilateral congenital blepharoptosis who underwent surgical correction through anterior levator resection. Shack-Hartmann wavefront sensor was employed to assess Zernike coefficients and root-mean-square. Computerized corneal topography, Orbscan and aberrometry were measured pre-and 3 months post-surgery in the healthy and ptotic eyes. Aberrometric changes were compared between patients with more than one diopter of astigmatism and subjects with less amount of astigmatism. Data were analyzed using the SPSS version 16. P < 0.05 was considered as significance level. RESULTS: Following anterior levator resection, the amount of astigmatism decreased. However, the difference was not statistically significant. Changes in topographic indices were not statistically significant. Regarding tomographic indices, the change in minimum keratometry was significant. The amount of change in total higher-order aberrations (HOAs) was not statistically significant. However, there was a decrease in the amount of third-order aberrations (vertical coma and vertical trefoil) which was statistically significant for vertical coma (-0.002 ± 0.001 vs. -0.08 ± 0.02 µm, P = 0.02). Comparing aberrometric changes in patients with more than 1 diopter astigmatism and less, there was a significant difference in the amount of HOA w/o Z400. CONCLUSION: Surgical correction of ptosis could reduce the ocular aberrations, despite no significant change in astigmatism. Nonaxial high-order aberrations are mostly affected probably due to the meridional effect of ptosis on the cornea.

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Objetivo: Caracterizar las aberraciones corneales de bajo orden en pacientes con ametropías miópicas. Métodos: Se realizó un estudio descriptivo, observacional y transversal, con una muestra de 104 ojos de 104 pacientes adultos con ametropías miópicas y un grupo control de 104 ojos de 104 voluntarios emétropes, que asistieron a consulta de Cirugía Refractiva del Instituto Cubano de Oftalmología. Se definieron las variables demográficas, clínicas y para la cuantificación de las aberraciones corneales la elevación-depresión y el valor cuadrático medio, aportadas mediante el mapa aberrométrico del Pentacam HR. Resultados: Hubo un predominio del sexo femenino, el rango de edad estuvo comprendido entre 18 y 39 años en ambos grupos. La mediana del equivalente esférico de los pacientes de ametropías miópicas fue -3,25 dioptrías, con agudeza visual sin corrección de 0,10, esfera de -2,63 D y cilindro de -1,00 D, 91 ojos (87,50 por ciento) tenían astigmatismo miópico compuesto. Los valores de elevación-depresión y el valor cuadrático medio de bajo orden fueron mayores en los pacientes con ametropías miópicas que los emétropes (p< 0,001). El astigmatismo vertical, desenfoque y el astigmatismo horizontal no presentaron diferencia estadísticamente significativa entre ambos grupos. Conclusiones: La miopía con o sin astigmatismo se debe estudiar y tratar como una aberración de bajo orden. Los valores de elevación-depresión y cuadrático medio son superiores en los ojos con ametropías miópicas respecto a los emétropes(AU)

Objective: To characterize low-order corneal aberrations in patients with myopic ametropia. Methods: A descriptive, observational and cross-sectional study was carried out with a sample of 104 eyes of 104 adult patients with myopic ametropia and a control group of 104 eyes of 104 emmetropic volunteers, who attended the Refractive Surgery Clinic of the Cuban Institute of Ophthalmology. Demographic and clinical variables were defined, and for the quantification of corneal aberrations, elevation-depression and average square value, provided by means of the Pentacam HR aberrometric map. Results: There was a predominance of female sex, the age range was between 18 and 39 years in both groups. The median spherical equivalent of myopic ametropia patients was -3.25 diopters, with uncorrected visual acuity of 0.10, sphere of -2.63 D and cylinder of -1.00 D, 91 eyes (87.50 percent) had compound myopic astigmatism. Elevation-depression values and low-order root average square value were higher in patients with myopic ametropes than emmetropes (p< 0.001). Vertical astigmatism, defocus and horizontal astigmatism showed no statistically significant difference between the two groups. Conclusions: Myopia with or without astigmatism should be studied and treated as a low-order aberration. The elevation-depression and average square values are higher in eyes with myopic ametropia than in emmetropic eyes(AU)

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BACKGROUND: To comprehensively evaluate the agreement of component corneal aberrations from the newly updated wavefront analysis software of a swept-source optical coherence tomographer (SS-OCT) and a referential Placido-topography combined OCT device in elderly cataract patients. METHODS: Retrospective study including 103 eyes from 103 elderly patients scheduled for cataract surgery that were measured on the same day with a SS-OCT (Heidelberg Engineering, Germany) device and a Placido-topography combined OCT device (CSO, Italy). Anterior, total, and posterior corneal wavefront aberrations were evaluated for their mean differences and limits of agreement (LoA) via Bland-Altman plots. Vector analysis was additionally employed to compare corneal astigmatism measurements in dioptric vector space. RESULTS: Mean differences of all corneal aberrometric parameters did not exceed 0.05 µm. Total corneal aberrations were not significantly different from 0 except for vertical coma (- 0.04 µm; P = 0.003), spherical aberration (- 0.01 µm, P < 0.001), and root mean square (RMS) higher-order aberration (HOA) (0.03 µm, P = 0.04). The 95% LoA for total corneal aberration parameters between both devices were - 0.46 to 0.42 µm for horizontal astigmatism, - 0.37 to 0.41 µm for oblique astigmatism, - 0.19 to 0.17 µm for oblique trefoil, - 0.33 to 0.25 µm for vertical coma, - 0.20 to 0.22 µm for horizontal coma, - 0.22 to 0.20 µm for horizontal trefoil, - 0.11 to 0.08 µm for spherical aberration, and - 0.22 to 0.28 µm for RMS HOA. Vector analysis revealed no statistically significant mean differences for anterior, total, and posterior corneal astigmatism in dioptric vector space. CONCLUSION: In eyes undergoing cataract surgery with a regular elderly cornea, corneal wavefront analysis from the SS-OCT device showed functional equivalency to the reference device. Nevertheless, clinically relevant higher order aberration parameters should be interpreted with caution for surgical decision-making.

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Objetivo: Determinar las aberraciones corneales en pacientes con indicación de cirugía refractiva con láser de excímeros. Métodos: Se realizó un estudio retrospectivo, transversal, descriptivo, con 161 ojos de 81 pacientes adultos, de ambos sexos con indicación de cirugía con láser de excímeros para la corrección de su defecto refractivo. Se definieron como variables edad, sexo, desenfoque, astigmatismo, coma, trefoil y aberración esférica, las que se determinaron por el estudio topográfico de rutina con el topógrafo KeratronTM Scout, Optikon. Resultados: Se obtuvieron los siguientes valores promedios: desenfoque -4,17 ± 0,29 D (-16,15 a 8,5 D) y absoluto 4,94 ± 0,199 (10 a 16,5 D), astigmatismo -1,56 ± 0,09 D (-9,44 a -0,09 D), coma 0,25 ± 0,016 (0,01 a 1,5 D), trefoil 0,204 ± 0,016 (0,01 a 1,18 D) y aberración esférica 0,316 ± 0,018 D (0,0 a 1,27D). En el 75 por ciento de los casos los valores absolutos de desenfoque fueron inferiores a 6,56, de astigmatismo inferior a 0,33 D, de coma menor que 0,33, trefoil inferior a 0,25 y aberraciones esféricas menores que 0,32 D. Conclusiones: Los valores promedio de las aberraciones corneales desenfoque, astigmatismo, coma, trefoil y aberración esférica se encuentran en el rango de los valores reportados en la literatura científica y la distribución de los valores de las aberraciones corneales presentan desplazamiento de la mayoría de los casos hacia los valores más bajo del rango de determinación(AU)

Objective: To determine corneal aberrations in patients indicated for excimer laser refractive surgery. Methods: A retrospective, cross-sectional and descriptive study was carried out with 161 eyes of 81 adult patients of both sexes with indication of excimer laser surgery for the correction of their refractive defect. Age, sex, defocus, astigmatism, coma, trefoil and spherical aberration were defined as variables, determined by routine topographic study with the KeratronTM Scout topographer, Optikon. Results: The following average values were obtained: defocus of -4.17 ± 0.29 D (-16.15 to 8.5 D) and absolute of 4.94 ± 0.199 (10 to 16.5 D), astigmatism of -1.56 ± 0.09 D (-9.44 to -0.09 D), coma of 0.25 ± 0.016 (0.01 to 1.5 D), trefoil of 0.204 ± 0.016 (0.01 to 1.18 D) and spherical aberration of 0.316 ± 0.018 D (0.0 to 1.27D). In 75 percent of the cases, the absolute values for defocus were lower than 6.56; for astigmatism, lower than 0.33 D; for coma, lower than 0.33; for trefoil, lower than 0.25; and for spherical aberrations, lower than 0.32 D. Conclusions: The average values of corneal aberrations for defocus, astigmatism, coma, trefoil and spherical aberration are in the range of values reported in the scientific literature, while the distribution of corneal aberrations values present displacement of most of the cases towards the lower values of the determination range(AU)

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BACKGROUND: To evaluate corneal topographic parameters in patients with psoriasis. METHODS: This prospective, cross-sectional study included 50 right eyes of 50 patients with psoriasis and 50 right eyes of 50 age- and sex-matched healthy individuals. Detailed dermatological and ophthalmological examinations were performed in all cases. Noninvasive tear break-up time (NIBUT), meibography, keratometry values, and high-order corneal aberrations (HOAs) were obtained using corneal topography and compared to healthy subjects. These values were also evaluated according to anti-tumor necrosis factor alpha (anti-TNF-α) use, the Psoriasis Area and Severity Index (PASI) score, psoriasis duration, and patient age. The chi-square test, Mann-Whitney U test, and Pearson correlation test were used for statistical assessment. RESULTS: Lower NIBUT and higher meibomian gland loss (MGL) were detected in psoriasis patients compared to healthy controls. There were no significant differences between the groups in terms of corneal HOAs. Higher MGL was detected in patients using anti-TNF-α than in patients not using it. A positive correlation was found among topographic parameters, especially between PASI score and the patient's age. No correlations were found between the disease duration and the other parameters. CONCLUSION: NIBUT and MGL are more common in psoriasis patients than in healthy subjects. The relationship between anti-TNF-α use, PASI score, patient age, and corneal parameters should be considered in the follow-up and treatment of ocular findings in psoriasis patients.

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AIM: To evaluate the efficacy of custom-made soft keratoconus (KC) lenses on corneal aberrations and photic phenomena in two different optical zones in patients with KC. METHODS: Sixty eyes of 42 patients with KC were examined at baseline and after fitting HydroCone (Toris K) soft silicone hydrogel lenses. Best spectacle-corrected visual acuity (BSCVA) and contact lens-corrected visual acuity (CLCVA) were recorded. Lower- and higher-order corneal aberrations (LOAs and HOAs) were measured with and without Toris K lenses and compared in central 4.5 mm and 7 mm zones. Mesopic pupil diameter and subjective photic phenomena were also assessed. RESULTS: Mean CLCVA was significantly improved compared to BSCVA (P<0.0001). Corneal curvature and refractive measurements were found to be significantly reduced by the use of Toris K lenses, except for posterior corneal curvature values. In the 4.5 mm central optical zone, all wavefront aberrations decreased significantly after lens fitting (P<0.0001). In contrast, in the 7 mm (peripheral) optical zone, values for HOAs, spherical and residual aberrations, and optical path differences were increased, while LOAs, trefoil, and quadrifoil coefficients were decreased. The rate of photic phenomena was significantly higher in participants with a pupil size >6.00 mm (85.7%). CONCLUSION: Toris K lenses provide good visual results and a significant reduction in central corneal aberrations in patients with KC but could cause an increase in peripheral aberrations. This practical and nonsurgical approach appears to be an effective method for the visual management of KC.

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Purpose: Low birth weight (BW) is associated with increased corneal aberrations in childhood and alterations of corneal geometry in adulthood. Increased corneal aberrations may be a factor contributing to decreased visual function in former low BW newborns in later life. Hence, the aim of this study was to analyze the long-term effect of low BW on corneal aberrations in adulthood.MethodsIn the German population-based Gutenberg Health Study (GHS) participants (age: 40–80 years) were examined with Scheimpflug imaging (Pentacam HR, Oculus Optikgeräte GmbH, Wetzlar, Germany). The relationship between self-reported BW and the different types of corneal aberrations was analyzed using linear regression analysis as uni- and multivariable analysis with adjustment for potential confounders. The main outcome measures were corneal aberrations defined as astigmatism (Z2−2; Z22), coma (Z3−1; Z31), trefoil (Z3−3; Z33), spherical aberration (Z40) and root-mean square of higher order aberrations (HOA; 3rd up to 8th order; aperture size: 6 mm).ResultsOverall, 5,628 participants were included in this analysis (3,004 women, aged 56.0 +/- 10.3 years). In a multivariable analysis lower BW was associated with decreased horizontal trefoil (B = 0.004 [0.001; 0.006] µm/500 g; p=.008); higher spherical aberrations (B=-0.006 [-0.008;-0.003] µm/500 g; p<.001), higher RMS (B=-0.028 [-0.042;-0.014] µm/500 g; p<.001), increased HOA (B=-0.007 [-0.010;-0.003] µm/500 g; p<.001) and increased LOA (B=-0.027 [-0.041;-0.013] µm/500 g; p<.001). No association was observed between birth weight and the other types of corneal aberrations in multivariable model.ConclusionOur results indicate an association between BW and spherical aberration in adults aged 40 to 80 years. This indicates that low BW may have an association with an altered corneal shape development which may affect optical image quality and, hence, visual function. (AU)

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PURPOSE: Low birth weight (BW) is associated with increased corneal aberrations in childhood and alterations of corneal geometry in adulthood. Increased corneal aberrations may be a factor contributing to decreased visual function in former low BW newborns in later life. Hence, the aim of this study was to analyze the long-term effect of low BW on corneal aberrations in adulthood. METHODS: In the German population-based Gutenberg Health Study (GHS) participants (age: 40-80 years) were examined with Scheimpflug imaging (Pentacam HR, Oculus Optikgeräte GmbH, Wetzlar, Germany). The relationship between self-reported BW and the different types of corneal aberrations was analyzed using linear regression analysis as uni- and multivariable analysis with adjustment for potential confounders. The main outcome measures were corneal aberrations defined as astigmatism (Z2-2; Z22), coma (Z3-1; Z31), trefoil (Z3-3; Z33), spherical aberration (Z40) and root-mean square of higher order aberrations (HOA; 3rd up to 8th order; aperture size: 6 mm). RESULTS: Overall, 5,628 participants were included in this analysis (3,004 women, aged 56.0 +/- 10.3 years). In a multivariable analysis lower BW was associated with decreased horizontal trefoil (B = 0.004 [0.001; 0.006] µm/500 g; p=.008); higher spherical aberrations (B=-0.006 [-0.008;-0.003] µm/500 g; p<.001), higher RMS (B=-0.028 [-0.042;-0.014] µm/500 g; p<.001), increased HOA (B=-0.007 [-0.010;-0.003] µm/500 g; p<.001) and increased LOA (B=-0.027 [-0.041;-0.013] µm/500 g; p<.001). No association was observed between birth weight and the other types of corneal aberrations in multivariable model. CONCLUSION: Our results indicate an association between BW and spherical aberration in adults aged 40 to 80 years. This indicates that low BW may have an association with an altered corneal shape development which may affect optical image quality and, hence, visual function.

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AIM: To evaluate the effect of preoperative degrees of myopic astigmatism and anterior corneal curvature on the functional optical zone(FOZ)after transepithelial photorefractive keratectomy(TransPRK).METHODS: Retrospective study was conducted on 78 patients(130 eyes)with myopia and myopic astigmatism who underwent TransPRK, and they were divided into control group(cylinder 0D), moderate astigmatism group(-0.50～-2.00D)and high astigmatism group(&#x003E;-2.00～&#x003C;-6.00D). The FOZ was measured and compared among the three groups 6mo after operation. The correlations between attempted correction, anterior corneal curvature, corneal aberrations, Q value, and the FOZ were analyzed.RESULTS: At 6mo after operation, the mean FOZ was 5.16±0.12mm in the control group, 5.29±0.23mm in the moderate astigmatism group, and 5.49±0.23mm in the high astigmatism group(P&#x003C;0.001), and the FOZ of the high astigmatism group was significantly higher than moderate astigmatism and control group(P&#x003C;0.05, P&#x003C;0.001); Pearson correlation analysis showed that the changes in spherical equivalent, total corneal higher-order aberrations(HOAs), coma, and spherical aberration were all negatively correlated with FOZ(all P&#x003C;0.05); and FOZ positively correlated with changes in the steep curvature(K2), mean curvature(Km), corneal astigmatism, and Q value(all P&#x003C;0.01). Multiple linear regression analysis showed that there was still positive correlation between preoperative K2 and FOZ after adjusting for other risk factors(P&#x003C;0.001).CONCLUSION: Patients with high astigmatism can obtain a larger FOZ and less induced coma after TransPRK. A larger FOZ can be achieved in eyes with steeper keratometry.

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Background/Aims: This study investigated whether there are changes in corneal surface regularity and corneal thickness in adults born small, appropriate, or large for gestational age at term. Methods: This retrospective cohort study involved prospective Scheimpflug imaging of the cornea (Pentacam®) to compare the corneal thickness and aberrations between adults classified as small for gestational age (SGA), normal birth weight (BW), and large for gestational age (LGA). Multivariable linear regression was applied to analyze associations with gestational age, BW percentile, placental insufficiency, preeclampsia, and breastfeeding. Results: In total, 448 eyes of 261 individuals born full term (aged 29.9 ± 9.5 years, 140 females) were examined, including 29 severe SGA (BW < 3rd percentile), 32 moderate SGA (BW between 3rd and <10th percentile), 132 normal BW (BW between 10th and 90th percentile), 35 moderate LGA (BW between >90th and 97th percentile), and 33 severe LGA (BW > 97th percentile). There were no differences between groups in the corneal aberrations of the total cornea as well as of the corneal front surface, except for higher-order aberrations in the front of the cornea (p = 0.032). There was an association between the increased total root mean square of higher-order aberrations and lower birth weight percentile (p = 0.004), with increased higher-order aberrations correlating with lower visual acuity and spherical equivalent. Conclusion: Restricted prenatal growth is associated with increased higher-order aberrations in adulthood.

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INTRODUCTION: Prematurity and retinopathy of prematurity (ROP) are associated with altered corneal shape and reduced visual acuity in childhood, but their long-term effects on corneal shape in later life are still unclear. This study evaluated whether prematurity and related perinatal factors are associated with corneal aberrations in adulthood. METHODS: The Gutenberg Prematurity Eye Study (GPES) is a cohort study using Scheimpflug imaging of the cornea. Associations were assessed between corneal Zernike aberrations and gestational age (GA), birth weight (BW), BW percentile, ROP occurrence, ROP treatment and other perinatal factors using univariate and multivariable linear regression analyses. RESULTS: This study involved 444 eyes of 256 individuals born preterm (aged 28.1 ± 8.4 years, 146 females) and 231 eyes of 132 individuals born full-term (aged 29.8 ± 8.9 years, 77 females). Multivariable analyses revealed an association between corneal higher-order aberrations and lower birth weight percentile (B = -0.001, p < 0.001) as well as ROP treatment (B = 0.120, p = 0.03). Corneal lower-order aberrations were also associated with lower birth weight percentile (B = -0.004; p = 0.001) and ROP treatment (B = 0.838, p = 0.01) but not with ROP occurrence. Increased corneal aberrations were correlated with lower visual acuity and the spherical equivalent refractive error. CONCLUSIONS: Perinatal factors, particularly low birth weight percentile and ROP treatment lead to a more irregular corneal shape in adulthood, thereby reducing optical image quality and potentially contributing to reduced visual acuity and altered refractive error.

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Objectives: The aim of the study was to present and compare 2 years results of mechanical photorefractive keratectomy (M-PRK) and transepithelial photorefractive keratectomy (T-PRK) for myopia. Methods: One hundred and nine eyes of 55 patients were included in this retrospective study. The mean age of the patients was 26.9±5.2 years. Forty-four eyes (40.4%) had M-PRK and 65 eyes (59.6%) had T-PRK. Follow-up time was 2 years. Refractive errors (RE), uncorrected visual acuity (UCVA), and high-order corneal aberrations were compared. Results: The mean RE was -2.33±0.88 D and the mean UCVA was 0.24±0.17 logMAR at baseline for M-PRK patients. At month 24, those measurements were changed to -0.27±0.32 D and 0.99±0.04 logMAR. The mean RE was 2.19±0.73 D and the mean UCVA was 0.23 ± 0.15 logMAR at baseline for T-PRK patients. At month 24, those measurements were changed to -0.14±0.32 D and 0.99±0.01 logMAR. The mean REs significantly decreased and the mean UCVA significantly increased after both type of surgeries (all p<0.001). In M-PRK group, 4 mm zone total corneal aberration and 6 mm total-coma-spherical corneal aberrations were statistically significantly increased in post-operative term. In T-PRK group, only 6 mm total-spherical corneal aberrations were statistically significantly increased in post-operative term. There was no serious complication during surgeries or follow-up time. Conclusion: M-PRK and T-PRK were a safe and effective in the treatment of myopia in 2 years term. Some high-order aberrations may be increase after those treatments.

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Background: The aim of this study was to analyze the long-term topographic and refractive outcomes of corneal cross-linking (CXL) in keratoconus. Methods: We used a retrospective observational study of patients with keratoconus who underwent CXL with a minimum follow-up of 5 years. Patients' refractive and topography data (corrected distance visual acuity, sphere, cylinder, average and maximum keratometry, and corneal aberrations) were collected. Results: A total of 112 patients/150 eyes (mean age: 33.2 ± 10.7 years; range: 13−61) were included. The mean follow-up was 5.87 ± 1.35 years (range: 5−10). At the last follow-up visit, an improvement in CDVA, spherical and cylindrical refraction, average and steepest keratometry, and corneal aberrations were observed (p < 0.05), with the exception of trefoil. At the last visit, 49 (34.8%) and 31 (22.0%) eyes had an improvement beyond 1D in their spherical and cylindrical power, respectively, and 43 (28.7%) eyes had a flattening of their steepest keratometry. Progressive improvement over time was observed for spherical refraction; max and mean-K; as well as corneal RMS, total, high, coma, and spherical aberrations (p < 0.05). More severe disease at the baseline correlated with an improvement in corneal aberrations over time. Conclusions: In addition to a progressive improvement in refractive and keratometric indices, corneal aberrations also demonstrate a steady decline with long-term follow-up after CXL, which was more pronounced in more severe patients.

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PURPOSE: To assess agreement between corneal aberration measurements made through swept-source optical coherence tomography using a new anterior segment imaging device (Anterion) and a Scheimpflug imaging device (Pentacam HR) in healthy subjects. METHODS: Cross-sectional study. In 50 eyes of 50 healthy subjects, 14 aberration parameters (7 across the anterior corneal surface and 7 across the total surface) were measured in 4 mm and 6 mm optic zones using each device: oblique trefoil (Z3_-3), vertical coma (Z3_-1), horizontal coma (Z3_1), horizontal trefoil (Z3_3), spherical aberration (Z4_0), root mean square (RMS) lower order aberrations (LOA) and RMS higher order aberrations (HOA). Data for the two devices were compared through intraclass correlation coefficients (ICC), paired t tests, limits of agreement (LoA) and Bland Altman plots. RESULTS: Vertical coma was the only corneal aberration parameter that consistently showed excellent agreement (ICC > 0.8, mean difference -0.019, LoA -0.165 to 0.126). Good agreement (ICC = 0.75) between the devices was observed for RMS HOA, but this was slightly worse in the 6 mm optical zone (ICC = 0.667 for anterior RMS HOA). No over- or underestimation trend by one or other device was noted. Agreement was poor to moderate for the rest of the corneal parameters (ICC 0.2 to 0.7). CONCLUSION: Despite good agreement overall for vertical coma and RMS HOA values, agreement for the remaining corneal aberration measurements was poor to moderate. As mean differences in our sample were overall small, in normal eyes these devices could be clinically judged as interchangeable.

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Purpose: This study aimed to evaluate the efficacy of small-incision lenticule extraction (SMILE) in improving vision and visual quality and correcting astigmatism for the treatment of high astigmatism. Methods: Eligible studies and studies comparing the efficacy of SMILE with femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) or transepithelial photorefractive keratectomy (T-PRK) for high astigmatism (≥2.00 D) were identified in PubMed, Embase, and the Cochrane Central Register of Controlled Trials, searched from their inception to 29 May 2022. The references of all searched studies were checked as supplements. The risk of bias was evaluated for each eligible study. The literature was screened according to the inclusion and exclusion criteria, and relative data were extracted. Data were extracted and analyzed by ReviewManager 5.4. The primary outcome was post-operative uncorrected distance visual acuity (UDVA). The secondary outcomes included corneal aberrations and vector parameters. The weight mean difference (WMD) and their 95% confidence intervals (95% CI) were used to assess the strength of the association. Results: A total of six studies including 380 astigmatism eyes were involved, with 211 high-astigmatism eyes and 31 low-astigmatism eyes undergoing SMILE surgery, 94 high-astigmatism eyes undergoing FS-LASIK surgery, and 44 high-astigmatism eyes undergoing T-PRK surgery. Compared with non-SMILE, SMILE induced more astigmatism (weighted mean difference [WMD] = -0.07, 95% CI [-0.12 to -0.02], P = 0.005) and fewer sphere aberrations (WMD = -0.12, 95% CI [-0.17 to -0.08], P < 0.00001). The post-operative UDVA, sphere, spherical equivalent (SE), and higher order aberrations in different surgeries were likewise equivalent. The difference vector and index of success were significantly higher, and the surgically induced astigmatism vector, correction index, and magnitude of error were significantly lower in SMILE. Conclusion: This meta-analysis suggests that SMILE, FS-LASIK, and T-PRK show excellent efficacy, predictability, and safety for myopia. SMILE exhibited less astigmatism refraction predictability and less surgically induced spherical aberrations. There may be more under-correction in SMILE. More randomized, prospective, and large sample-sized studies are needed to confirm these conclusions in the long term.

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INTRODUCTION: This study investigated the long-term visual and optical quality changes after small incision lenticule extraction (SMILE) for the correction of moderate to high myopia. METHODS: Forty-one eyes of 41 patients with a mean spherical equivalent (SE) of - 6.74 ± 1.45 D undergoing SMILE were enrolled. Preoperative and 1-month, 3-month, 1-year and 5-year postoperative follow-up examinations were performed including visual acuity, manifest refraction, corneal aberrations and contrast sensitivity. An optical quality analysis system was used to measure objective scatter index (OSI), Strehl ratio (SR) and modulation transfer function cutoff frequency (MTFcutoff). RESULTS: The safety and efficacy indices were 1.09 ± 0.12 and 1.03 ± 0.17, respectively, at the 5-year follow-up. No significant changes in SE from 1 month to 5 years postoperatively were found. The OSI significantly increased at 1 and 3 months postoperatively (p < 0.01 and p < 0.01) and declined at 1 and 5 years (p = 0.81 and p = 0.87). MTFcutoff and SR showed similar trends. Coma, spherical aberration and total higher-order aberration significantly increased after SMILE (p < 0.01) and remained stable from 1 month to 5 years after surgery (p > 0.05). Contrast sensitivity in the photopic and mesopic condition showed no significant changes during 5-year follow-up (p > 0.05). CONCLUSION: The SMILE procedure is satisfactory in terms of optical quality for correcting moderate and high myopia in the long-term period. TRIAL REGISTRATION: ChiCTR-ONRC-13003114.

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We aimed to investigate the change patterns in corneal sub-basal nerve morphology and corneal intrinsic aberrations in dry eye disease (DED). Our study included 229 eyes of 155 patients with DED and 40 eyes of 20 healthy control. We used the Oculus keratograph and the ocular surface disease index questionnaire to assess their signs and symptoms. In vivo confocal microscopy was used to observe the corneal sub-basal nerves, corneal endothelial cells, and Langerhans cells (LCs). An artificial intelligence (AI) technique run by the deep learning model generated the sub-basal nerve fibre parameters. Furthermore, we used the Pentacam HR system to measure the corneal intrinsic aberrations and corneal surface regularity indices. DED patients more frequently had increased anterior and total corneal aberrations than controls (P < 0.05). In addition, DED had decreased average density and maximum length of corneal nerve. (Both P < 0.01) The LC number was significantly correlated with maximum length (CC = -0.19, P = 0.01) of the sub-basal nerve fibre. Furthermore, the corneal nerve average density was negatively correlated with IHD, and anterior, posterior, and total corneal aberrations (All P < 0.05) especially the higher-order aberrations. Significant correlations were seen between corneal nerve morphology changes, analysed by AI and corneal intrinsic aberrations, particularly higher-order aberrations.

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PURPOSE: To evaluate ocular surface status and corneal higher-order aberrations after a new ocular nebulization therapy combined with meibomian gland massage for the treatment of meibomian gland dysfunction (MGD). PATIENTS AND METHODS: This prospective randomized study involved 38 patients diagnosed with MGD. Subjects were classified into two groups: the nebulization and meibomian gland massage group (or NB group, 14 patients, 28 eyes) and the eye drop group (or ED group, 24 patients, 48 eyes). Azithromycin solution and esculin and digitalis glycoside eye drops were tested in the therapy. Best-corrected visual acuity (BCVA) testing; noncontact tonometry; fundoscopy; the Ocular Surface Disease Index (OSDI) questionnaire; tear film assessment encompassing tear meniscus height (TMH) and non-invasive keratograph breakup time (NIKBUT); corneal fluorescein staining; the Schirmer I test (SIT); and anterior, posterior and total corneal aberrations were evaluated at 1 and 3 months after treatment. RESULTS: At 3 months, the NB group showed significantly better improvement than the ED group in terms of TMH (0.23 ± 0.04 versus 0.19 ± 0.05, p = 0.002) and first breakup time (f-BUT; 7.42 ± 2.49 versus 5.53 ± 2.12, p = 0.001). The average breakup time (Av-BUT) of the NB group was significantly longer than that of the ED group at 1 month (9.52 ± 2.70 versus 8.02 ± 2.33, p = 0.013) and 3 months (5.53 ± 2.12 versus 8.35 ± 2.38, p = 0.018). Both groups achieved improvement in corneal fluorescein staining (CFS) and SIT results at 1 and 3 months (p < 0.05). At the 3-month follow-up, anterior corneal trefoil aberrations decreased significantly in the NB group (p = 0.008), and improvements in anterior corneal coma aberrations and posterior corneal higher-order aberrations (HOAs) were observed in the ED group (p < 0.05) over the 4 mm pupil zone. Over a 6 mm zone at 3 months, anterior, posterior and total trefoil aberrations as well as total HOAs were significantly decreased in the NB group (p < 0.05), while posterior HOAs and trefoil aberrations were found to be decreased in the ED group (p < 0.05). For individual Zernike terms, anterior and total corneal Z(3, -3) showed decreases over the 4 and 6 mm zones, while no improvement was detected in the NB group at 3 months. CONCLUSION: In terms of comfort and visual quality, nebulization therapy combined with meibomian gland massage to deliver azithromycin solution and esculin and digitalis glycoside eye drops appears to be more effective in treating clinical symptoms and signs of MGD than simply applying esculin and digitalis glycoside eye drops.

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CLINICAL RELEVANCE: Children with anisometropia have different refractive errors in each eye. Studies reported similar ocular higher-order aberrations (HOAs) in each eye within anisometropia. It is unclear whether binocular corneal HOAs within anisometropia are likewise similar. This study compared interocular differences in corneal HOAs among children with anisometropia, and explored correlations between corneal HOAs and anisometropia. BACKGROUND: This study aimed to compare interocular differences in corneal aberrations in children with low and high anisometropia and to determine correlations between the size of interocular differences in corneal HOAs and the degree of anisometropia. METHODS: This was a retrospective, self-controlled study: 69 children with myopic anisometropia were divided into a high anisometropia group (34 children, interocular difference in spherical equivalent refraction ≧2D) and a low anisometropia group (35 children, 2D >interocular difference in spherical equivalent refraction ≧1D). Binocular corneal aberrations were measured using Sirius combined corneal topographer and tomographer. Paired t-tests, Wilcoxon rank sum tests, and Spearman correlation analyses were used in the current study. RESULTS: For the low anisometropia group, there were no statistically significant interocular differences in corneal HOAs (P>0.05). For the high anisometropia group, higher myopic eyes had lower coma in 3mm diameter than those of the contralateral eyes (in the total cornea and the anterior corneal surface; P<0.05). No interocular difference was found in corneal total higher-order aberration and spherical aberration in the high anisometropia group (P>0.05). Among all 69 children with anisometropia, interocular differences in coma were not correlated with the degree of anisometropia (P>0.05). CONCLUSION: For children with high anisometropia, higher myopic eyes had lower coma than those of the contralateral eyes. However, no obvious correlation was found between interocular differences in coma and the degree of anisometropia.

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