Objectives: To compare the vector analysis, visual, and refractive outcomes of femtosecond-assisted laser insitu keratomileusis (LASIK) and small incision lenticule extraction (SMILE) among myopic patients with moderate myopic astigmatism. Methods: This was a single-center, retrospective, cohort study that compared eyes that underwent femtosecond LASIK or SMILE for the correction of myopia and astigmatism of 0.75 to 3.0 diopters. Vector analysis and standard graphs for reporting visual and refractive outcomes were utilized for analysis. Results: There were 82 femtosecond LASIK-treated eyes and 80 SMILE-treated eyes with similar preoperative characteristics except for slightly higher mean preoperative sphere refraction in the SMILE group (-4.2±2.4 D vs -4.9±1.6 D, p=0.03). At 3 months, femtosecond LASIK group had better mean uncorrected distance visual acuity (UDVA) (LogMAR 0.006±0.06 vs 0.06±0.09, p=0.00) and had more eyes achieving postoperative UDVA of 20/20 or better (88% versus 56%). Although there were similar postoperative spherical equivalents, residual astigmatism was higher in the SMILE group (0.11±0.22 D vs 0.32±0.30 D, p=0.00). Vector analyses showed significantly better outcomes for femtosecond LASIK than for SMILE in terms of difference vector (DV), index of success (IOS), torque, and flattening index (FI). A trend for undercorrection for higher astigmatism was seen in both groups that was greater in the SMILE group. Both groups showed high safety with the majority of eyes showing postoperative corrected distance VA (CDVA) within 1 line of preoperative CDVA (98.8% versus 91.2%). Conclusion Although femtosecond LASIK and SMILE have similar predictability at 3 months, femtosecond LASIK has relatively better efficacy and superior astigmatic outcomes than SMILE for the correction of moderate myopic astigmatism.
Astigmatism

A survey on the myopia in 579 pupils of 2 primary schools o Tan Mai and Van Noi in Ha Noi was carried out. Results showed that: light intensity was at the hygienic standard, but in some sitting places the ligh intensity was too high. The height of the desks were not compatible with the height of the pupils. The poor vision was 17%, the refraction problem was 24%, hypermetropic myopic astigmatism were 11%, some influence factors to vision disorder of the pupils were found out initially. The vision disorder of the pupils at Tan Mai school was significant higher than this in Van Noi school.
Myopia ; Astigmatism

To evaluate surgically induced astigmatism for 6 months following 3.2mm scleral tunnel incision cataract surgery according to incision site we divided 115 patients(124 eyes) into superior incision group 1 (58 eyes) and superotemporal incision group 2 (66 eyes). Each group was classified into 3 cases according to preoperative astigmatism. Postoperative astigmatic changes by vector method were 0.40 diopter(D) against-the-rule astigmatism(ATR) in group 1, 0.25 D ART in group 2 at 6 months and there was no difference between two groups(P>0.05). In the preoperative with-the-rule astigmatic cases, postoperative astigmatic changes were 0.56 D ART in group 1, 0.38 D ATR in group 2, in the preoperative against-the-rule astigmatic cases, postoperative astigmatic changes were 0.25 D ART in group 1, 0.12 D ART in group 2, in the preoperative no astigmatic cases, postoperative astigmatism changes were 0.53 D ATR in group 1, 0.25D ART in group 2 at 6 months. There was no significant difference between two groups in postoperative astigmatic changes(P>0.05) and corneal astigmatisms were stabilized after 2 months postoperatively in both groups(P<0.05).
Astigmatism* ; Cataract*

PURPOSE: To compare the corneal higher-order aberrations (HOAs) of normal young subjects using Galilei(TM) G4 (Zeimer, Port, Switzerland) and Pentacam(R) (Oculus Inc., Wetzlar, Germany). METHODS: Corneal HOAs were measured using Galilei(TM) G4 and Pentacam(R) in 41 healthy individuals (41 eyes). Intraclass correlation coefficients (ICCs) were obtained to evaluate the repeatability of the 2 devices. Differences in HOAs between the 2 instruments were analyzed with a paired t-test and correlations evaluated. RESULTS: All ICCs measured using Galilei(TM) G4 and Pentacam(R) showed more than moderate repeatability (>0.81) except trefoil, tetrafoil, 4th and 5th HOAs. When comparing the measurements obtained with Galilei(TM) G4 and Pentacam(R), total HOAs, spherical aberration (SA), secondary astigmatism and 5th total HOAs were statistically significantly different between the 2 device (all p < or = 0.001). In addition, Galilei(TM) G4 and Pentacam(R) showed discrepancy among all corneal HOAs items. Although the total corneal HOAs and the SA were significantly correlated, other HOA measurements generally exhibited a low correlation. CONCLUSIONS: Corneal HOAs obtained by the 2 instruments cannot be used interchangeably due to their differences and discrepancy although corneal HOAs measured using Galilei(TM) G4 and Pentacam(R) showed relatively high repeatability.
Astigmatism ; Lotus

Objective: To determine the effect of corneal collagen cross-linking on the corneal curvature of eyes with keratoconus measured using an Oculus Pentacam® at 2 years and annually thereafter. Methods: This was a descriptive, retrospective study involving patients with keratoconus who had undergone uncomplicated collagen cross-linking using the Dresden protocol from January 2012 to March 2016. Baseline measurements of best-corrected visual acuity (BCVA), maximum K value (Kmax), corneal astigmatism, anterior and posterior elevation map changes were recorded and compared with data taken at 2 and 3 years Results: This study included 32 patients (48 eyes) with a mean follow-up of 28.88 ± 6.23 months. Only 4 patients (6 eyes) had 3-year follow-up data with a mean follow-up of 42.83 ± 4.58 months. When all eyes were considered, significant changes were noted in Kmax, BCVA, and anterior and posterior elevation maps between baseline and 2-year follow-up. Specifically, there were significant decreases in Kmax (p<0.0001) and anterior elevation (p<0.05), and significant improvement in BCVA (p<0.01) while posterior elevation (p<0.0001) was found to have increased significantly at 2nd year follow-up compared to baseline. When only eyes with 3-year follow-up data was analyzed, only BCVA showed significant change (p<0.05). Corneal astigmatism remained stable during the study period. Conclusion Two to 3 years after collagen cross-linking for keratoconus, corneal curvature parameters and BCVA showed improved and stable outcomes when compared to baseline.
Keratoconus ; Astigmatism

Postoperative changes of keratometric astigmatism were analysed in 137 cases of phacoemulsification and foldable silicone posterior chamber lens implantation using clear corneal incision. The subjects were divided into two groups; Group 1 comprised 36 eyes which underwent surgery using a superior approach, Group 2 comprised 101 eyes which underwent surgery using a temporal approach. Surgically induced keratometric astigmatism in Group 1 was -1.14+/-1.02 diopter(D) at one day, -0.98+/-1.03 D at one week, -0.58+/-0.94 D at two months after operation, and in Group 2 was 0.69+/-0.97 D at one day, 0.96+/-1.08 at one week, 0.63+/-0.68 at two months after operation. The difference of absolute astigmatism between two groups was statistically significant(p<0.05) at one day after operation. But there was no statistically significant difference at one week and two months after operation. Temporal incision induced less astigmatism than superior incision temporarily in cataract surgery using clear corneal incision.
Astigmatism* ; Cataract* ; Phacoemulsification ; Silicones

Management of surgically induced astigmatism is the major problem for surgeons implanting intraocular lenses. Besides corneal astigmatism, the fixation status of the intraocular lens(IOL) may contribute to postoperative astigmatism. This study was undertaken to analyze whether the variable factors such as fixation status, IOL type, and capsulotomy method affect tilting and decen tration of IOL. The tilting angle and decentration of the IOL were measured by image-processing technique using computerized Scheimpflug camera. The average tilting angle was 4.30 +/- 2.21 degree. The average decentration was 0.44 +/- 0.36mm from the corneal center. Based on these data, the astigmatic error induced by the tilting and/or decentration of the implanted IOL was calculated as within 0.1 diopter. Haptic fixation and designs were statistically significant for IOL posit ion but tilting and decentration were not significantly associated with capsulotomy method, agegroup, sex, and postoperative day.
Astigmatism* ; Lenses, Intraocular

PURPOSE: The present study investigates the patterns of internal optical aberrations in eyes with different types of cataract. METHODS: Eighty eyes of 70 cataract patients were included in the present study. Internal optical aberrations were measured with a KR-1W wavefront aberrometer before cataract operation. Types of cataract were classified into three groups; cortical, nuclear and posterior subcapsular cataracts. The differences in the results of the wavefront data of 6-mm pupil diameter zones were compared among three groups. The Kruskal-Wallis test and Mann-Whitney U test were used for comparing data. RESULTS: A total of 80 eyes consisting of 30 cortical cataracts, 30 nuclear cataracts and 20 posterior subcapsular cataracts were found. In the 6-mm pupil diameter zone, the average internal spherical aberrations by original value were 0.042 microm of cortical cataracts, -0.092 microm of nuclear cataracts and -0.109 microm of posterior subcapsular cataracts. The average internal spherical aberrations by absolute value were 0.122 microm of cortical cataracts, 0.533 microm of nuclear cataracts and 0.202 microm of posterior subcapsular cataracts. The internal spherical aberrations by original value were not statistically significantly different, but by absolute value were statistically significantly different (p = 0.003, Kruskal-Wallis test). Nuclear cataracts have a much higher positive or negative value than other cataract groups in the distribution of internal spherical aberrations by original value for each type of cataract. Other than this difference, the internal astigmatism and internal high order aberrations were not statistically significantly different. CONCLUSIONS: The change in internal spherical aberrations of nuclear cataract from the original value was larger than cortical and posterior subcapsular cataract. Therefore, nuclear cataracts have much higher positive or negative values than other cataract groups.
Astigmatism ; Cataract* ; Humans ; Pupil

Keratomileusis-in-situ was performed on 18 eyes(15 patients) to correct high myopia. Average preoperative spherical equivalent was -19.26 diopter(D) with a range of -13.25 to -30.50D. The mean postoperative myopia was -4.80D(-0.00 to -9.00D), checked at 6 months postoperatively. Preoperative corneal refractive power was +43.63D, while it decreased to +35.41D at 6 months postoperatively Of all the cases, there was no significant complication except the one who had irregular astigmatism caused by the epithelial ingrowth in the interface. Uncorrected vision of all the patients improved markedly, compared to those preoperatively. In conclusion, keratomileusis-in-situ is a feasible technique for correcting high amounts of myopia, though the calculation program might be improved to obtain adequate prediction.
Astigmatism ; Humans ; Myopia*

We evaluated the corneal topography of 109 eyes which have 1 diopter or more astimatism, with computer-assisted videokeratography(Eye Sys CAS). There was 11% with round pattern, 17.4% with oval pattern, 49.5% with symmetric bow-tie pattern, 19.3% with assymmetric bow-tie pattern, 2.8% with irregular pattern. 70% of subjects had right and left eyes classified into the same group. There was statistically significant difference among the patterns for keratometric astigmatism and difference among the groups which were classified by the location of the area of highest refractive power for keratometric and total astigmatism. The mean angular separation between flat and steep meridian was 89.2 degrees and ranged from 78.61 degrees to 100.67 degrees. The mean residual astigmatism was 0.547 diopter. In the with-the rule astigmatism type, when the total astigmatism less than 1.89 diopter, residual astigmatism neutralize the corneal astigmatism, but when the total astigmatism increase more than 1.89 diopter, residual astigmatism tend to increase the total astigmatism.
Astigmatism* ; Classification* ; Corneal Topography*