ABSTRACT
AIM:To evaluate the agreement of corneal high-order aberrations from Topcon KR-1W, i.Profiler and OPD-Scan Ⅲ wavefront aberrometers in myopic adults.METHODS:A prospective clinical study. A total of 92 adult patients(92 eyes)with myopia in the department of optometry, the People's Hospital of Guangxi Zhuang Autonomous Region from June to August 2022 were enrolled. The third-order and fourth-order corneal aberrations at the pupil diameter of 4 and 6mm were measured by Topcon KR-1W, i.Profiler, and OPD-Scan Ⅲ, respectively. The difference and agreement of the three aberrometers were evaluated.RESULTS: The measurements at 6mm pupil diameter were all greater than those at 4mm pupil diameter. Although there were no statistical differences in the measurements of Z-44、Z-24 by the three aberrometers at 4 pupil diameter(P>0.05), there were statistical differences in other measurements(P<0.05). The aberration results measured by the three aberrometers were statistically different at the 6mm pupil diameter(P<0.05). The 95% limit of agreement(95%LoA)of the measurements of higher-order aberration, including the third-order aberrations at 4mm pupil diameter and the third-order and fourth-order aberrations at 6mm pupil diameter(except for the Z-24)were greater than 0.1μm. The concordance correlation coefficient(Pc)was lower than 0.90, indicating a poor consistency. The correlation coefficients of corneal higher-order aberrations were significantly different among the three aberrometers at 4 and 6mm pupil diameter(r4mm=0.215～0.805, P4mm<0.05; r6mm=0.561～0.916, P6mm<0.001).CONCLUSION:There were significant differences in the measurements of the third- and fourth-order corneal aberrations at 4 and 6mm pupil diameter among Topcon KR-1W, i.Profiler, and OPD-Scan Ⅲ, and the agreements were poor, so they are not interchangeably in clinical applications.
ABSTRACT
AIM:To observe the changes in corneal aberrations and the characteristics of visual quality after transepithelial photorefractive keratectomy(T-PRK)and femtosecond small incision lenticule extraction(SMILE)in the correction of low myopia.METHODS: Prospective cohort study. A total of 32 cases(32 eyes)with low myopia who underwent T-PRK surgery and 45 cases(45 eyes)of SMILE surgery at Weifang Eye Hospital from April 2021 to April 2022 were selected. The uncorrected visual acuity(UCVA), best corrected visual acuity(BCVA), spherical equivalent(SE), corneal higher-order aberrations(HOAs)and objective visual quality were compared between the two groups.RESULTS:All patients completed the surgery successfully without complications such as infection. At 3mo postoperatively, the safety index was 1.13±0.16 and 1.16±0.17(P=0.48)and the efficacy index was 1.10±0.20 and 1.15±0.18(P=0.27)in the T-PRK and SMILE groups, respectively. The percentage of UCVA(LogMAR)≤0 in the T-PRK and SMILE groups was 94% and 98%, respectively. The percentage of the residual SE within ±0.5D was 88% and 87% in the two groups, respectively. The HOAs and spherical aberration in both groups were significantly increased(P≤0.01), and the increase was not statistically significant between the two groups(P=0.31, 0.89). There was no significant change in horizontal coma, horizontal trefoil and vertical trefoil in both groups(P&#x003E;0.05). The vertical coma in SMILE group was significantly increased(P&#x003C;0.001), while there was no significant change in T-PRK group(P&#x003E;0.05), and the increase was significantly greater in SMILE group than in T-PRK group(P&#x003C;0.001). There was no significant difference in objective scattering index(OSI), modulation transfer function cut off frequency(MTFcut off), Strehl ratio(SR), visual acuity(VA)100%, VA20% and VA9% between the two groups(P&#x003E;0.05).CONCLUSION:Both T-PRK and SMILE showed good safety, efficacy, and visual quality in correcting low myopia, while SMILE induced more vertical coma than T-PRK.
ABSTRACT
Objective:To observe the corneal morphology and visual quality after transepithelial photorefractive keratectomy (Trans-PRK) with smart pulse technique (SPT) and 1 050 Hz cutting frequency in the correction of myopia and astigmatism.Methods:A self-controlled case series study was conducted.Sixty five eyes of 33 patients who underwent Trans-PRK surgery in Ineye Hospital of Chengdu University of TCM from July 2017 to June 2018 were followed up for 6 months.The uncorrected visual acuity (UCVA) converted to logarithm of the minimum angle of resolution (LogMAR) unit, best corrected visual acuity (BCVA) (LogMAR), and spherical equivalent (SE) of the subjects were recorded.The anterior corneal surface symmetry index (SI), the anterior corneal surface Q value in the range of 6, 7, 8, and 9 mm diameter, the spherical aberration, coma, trefoil and total higher-order aberration of the anterior corneal surface, the strehl ratio (SR), and the modulation transfer function (MTF) of 10, 20, 30, and 40 c/d in the horizontal and vertical meridian directions before and after surgery were measured with Sirius corneal topography analyzer.The differences of each index among different time points were compared, and the correlation between indexes was analyzed by Pearson correlation analysis.This study followed the Declaration of Helsinki.The study protocol was approved by the Medical Ethics Committee of Ineye Hospital of Chengdu University of TCM (No.2020yh-004). All patients signed the informed consent form before surgery.Results:The average preoperative BCVA and SE were -0.09±0.06 and (-4.24±1.24)D.The mean UCVA and SE at 7 days, 1, 3 and 6 months postoperatively were -0.10±0.08 and (0.03±0.63)D, -0.12±0.06 and (0.08±0.53)D, 1.16±0.06 and (0.02±0.79)D, -0.18±0.05 and (0.08±0.37)D, respectively.The SI at different time points after the surgery were significantly higher than that before operation (all at P<0.05). At 1, 3 and 6 months after surgery, the Q value of anterior corneal surface in different diameter ranges increased from negative to positive, showing statistically significant differences (all at P<0.05). At each time point after surgery, the trefoil and total higher-order aberrations of the anterior corneal surface increased to varying degrees.Coma at 7 days and 6 months after surgery were significantly higher than that before surgery, and spherical aberration at 3 and 6 months after surgery were significantly higher than that before surgery (all at P<0.05). The SR values at 3 and 6 months after operation were significantly higher than that before operation (all at P<0.05). At 6 months after operation, the MTF values at different spatial frequencies of the horizontal meridian and the MTF values at 30 and 40c/d spatial frequencies of the vertical meridian were lower than those before operation, and the differences were statistically significant (all at P<0.05). The correlation analysis showed that the Q value of different diameter ranges was positively correlated with spherical aberration ( r=0.798-0.925, P<0.05), total higher-order aberration ( r=0.596-0.630, P<0.05), SI ( r=0.235-0.303, P<0.05) and corneal ablation depth ( r=0.583-0.659, P<0.05) at 6 months after surgery.SI was positively correlated with spherical aberration ( r=0.307, P<0.05), coma ( r=0.424, P<0.05), total higher-order aberration ( r=0.300, P<0.05), corneal ablation depth ( r=0.227, P<0.05), and eccentric cutting amount ( r=0.281, P<0.05). There was no correlation between SR and aberration, corneal ablation depth, eccentric cutting amount, etc.(all at P≥0.05). Conclusions:Trans-PRK using SPT to correct myopic astigmatism can improve vision, stabilize diopter, enhance retinal imaging quality, increase the asymmetry of the anterior corneal surface, and introduce different degrees of higher-order aberrations.
ABSTRACT
PURPOSE: To investigate the types of corneal higher-order aberration (HOA) induced by pterygium, residual corneal HOA after pterygium surgery, and correlations between corneal HOA and the length of the pterygium. METHODS: Fifty-three patients who underwent pterygium excision with conjunctival autograft were enrolled. Corneal HOA was measured by Pentacam® (Oculus Inc., Wetzlar, Germany) preoperatively and 3 months postoperatively in the 6-mm optical zone. Preoperative and postoperative HOAs of eyes with pterygium were compared with HOAs of the fellow eye to evaluate HOAs induced by pterygium and residual HOAs after pterygium surgery. Partial correlation analysis was performed to investigate the relationship between HOAs and the length of pterygium. A postoperative HOA less than 0.35 µm in size was defined as a favorable surgical outcome and the surgical indications were estimated using receiver operator characteristic (ROC) curve. RESULTS: Horizontal coma, root mean square (RMS) of coma, oblique trefoil, horizontal trefoil, RMS of trefoil, and total HOA were significantly greater in the eye with preoperative pterygium. Three months after pterygium excision, only RMS of coma and total HOA remained significantly greater in eyes with pterygium. Vertical coma, horizontal coma, RMS of coma, and oblique tetrafoil were correlated with pterygium length. Pterygium excision when pterygium length was less than 1.6 mm led to favorable surgical outcomes. CONCLUSION: Pterygium induced greater than third-order corneal HOAs and these HOAs were corrected via pterygium surgery. Longer pterygium length was associated with larger RMS of coma and larger coma RMS persisted after pterygium surgery. A pterygium length of 1.6 mm should be considered the cutoff for pterygium excision for reducing postoperative corneal HOA.
Subject(s)
Humans , Autografts , Coma , Lotus , PterygiumABSTRACT
@#AIM:To investigate the accuracy, time-consuming and reliability of three Zernike algorithms in reconstruction of the corneal aberration in adaptive optics.<p>METHODS: Elevation data of corneal front surface collected on 20 normal eyes over a 6mm pupil were converted into the simulated original wave-front data by subtracting the best fitting sphere, which was then resampled at resolutions of 100, 300, and 500μm. Differences in elevation between adjacent pixels were used to generate simulated wave-front slope data, which were used to reconstruct wave-front by three algorithms: the regularized solution, the singular value decomposition, and Householder transform separately. The number of Zernike modes was from 1 to 130 separately in each reconstruction procedure. Each new wave-front map generated was directly compared to the originally sampled wave-front and the residual root-mean-square(RMS)error between the original and reconstructed map was recorded, also we investigate the time-consuming and reliability of the solution by calculating the condition numbers of the linear model and observing the mode coefficient matrix. <p>RESULTS: Householder transformation performed as well as the singular value decomposition by three sampling rates in reconstruction accuracy, while the regularized solution showed unacceptable results when the number Zernike modes used higher than 88 by the resolution was 500μm. With the modes number increased, the time that the singular value decomposition consumed increased more obviously than the time that the Householder transformation and the regularized solution consumed, and the difference between the latter two didn't show obviously. The higher the sampling rate was, also the lower the Zernike exponent number was, and the more reliable the result was, and the instability of regularized solution is more serious than the other two at the low sampling rate.<p>CONCLUSION:Householder transformation is superior the other two in accuracy as well as the highly effectiveness, and the reliability of three algorithms was almost identical at high sampling rate, while the Householder transformation still showed relatively stable performance at low sampling rate, which provides the reference and the theory basis of choice to the optimal algorithm which is applied in the adaptive optics system of real-time correction eyeball's aberration wave-front reconstruction.
ABSTRACT
PURPOSE: To evaluate the efficacy of 0.05% cyclosporine A on tear film parameters and corneal aberration after cataract surgery. METHODS: Patients who underwent cataract surgery were divided into 2 groups. Patients in Group I (23 eyes) were treated with cyclosporine A from 1 week before surgery to 3 months after surgery. Patients in Group II (24 eyes) underwent surgery without cyclosporine treatment. Tear film break-up time (BUT), Schirmer's test I, Oxford scheme, Ocular surface disease index (OSDI), and corneal aberrations were evaluated before surgery and at 1 and 3 months after surgery. RESULTS: In Group I, BUT was significantly improved at 3 months (p = 0.026) after surgery compared with the preoperative value. OSDI decreased significantly at 1 (p = 0.033) and 3 months (p = 0.003) after surgery compared with the preoperative value. However, there were no significant differences between preoperative and postoperative values of BUT and OSDI in Group II. Schirmer's test results and the Oxford scheme were not significantly changed in either group. Preoperative root mean square (RMS) total values were not different between the 2 groups, but was different at postoperative 3 months (p = 0.015). Group I had a significantly lower value for total RMS than Group II. In Group I, Coma 7 (Z3(-1)) (p = 0.018) and spherical aberration (Z4(0)) (p = 0.031) were significantly decreased after surgery. In Group II, Trefoil 6 (Z3(-3)) (p = 0.033) was significantly increased after surgery. CONCLUSIONS: 0.05% cyclosporine A may be effective for improving dry eye syndrome and corneal aberration after cataract surgery.
Subject(s)
Humans , Cataract , Coma , Cyclosporine , Dry Eye Syndromes , Lotus , TearsABSTRACT
PURPOSE: To evaluate changes in corneal and ocular high-order aberration, ocular fatigue, and tear break-up time (TBUT) before and after playing computer games and the correlations among the variables. METHODS: Thirty-nine normal healthy subjects played computer games for 1 hour. Ocular fatigue was evaluated with a questionnaire, TBUT was measured with slit-lamp biomicroscopy, and high-order aberrations were measured with a KR-1W aberrometer (Topcon Medical System, Inc., Tokyo, Japan) in each subject before and after playing computer games. The right eye was used for statistical analyses. RESULTS: Subjective ocular fatigue (expressed as the interview score) increased from 4.23 +/- 5.35 to 12.05 +/- 8.68 after playing games (p < 0.001) and TBUT decreased from 8.03 +/- 6.43 sec to 4.90 +/- 3.31 sec (p < 0.001). Ocular high-order aberrations in the 4 mm and 6 mm zones were not significantly changed before and after playing games (p = 0.150, p = 0.202, respectively). However, corneal high-order aberrations in the 4 mm and 6 mm zones were significantly increased after playing computer games (p = 0.002, p = 0.002, respectively). Changes in TBUT, interview score, and corneal high-order aberration were not correlated with each other. CONCLUSIONS: Playing computer games increased corneal high-order aberrations as well as subjective ocular fatigue and TBUT.
Subject(s)
Eye , Fatigue , Surveys and Questionnaires , TokyoABSTRACT
PURPOSE: To assess the changes of corneal aberration in the front and rear surface measured by Pentacam(R) following cataract surgery. METHODS: Thirty-two eyes of 30 consecutive patients that underwent phacoemulsification and IOL insertion via 3 mm superotemporal corneoscleral incision were examined. The corneal aberration was measured with Pentacam(R) (Oculus, Wetzlar, Germany) at 1 week and 1 month after the surgery, and these postoperative values were compared with values taken before the operation. The data were analyzed from 6 mm pupil size, using Zernike's polynomial expansion. RESULTS: In anterior corneal aberration, Z (4, -2); secondary astigmatism at 1 week postoperatively and Z (3, -3); the trefoil at 1 month postoperatively changed significantly (p<0.05). By contrast, in posterior corneal aberration, Z (2, -2), Z (2, 0), Z (2, 2), Z (3, 1), Z (4, -4), and Z (4, -2) changed significantly (p<0.05). However, there were no significant changes at 1 month postoperatively (Paired t-test). CONCLUSIONS: There were significant changes in posterior corneal aberration compared to anterior corneal aberration at 1 week postoperatively. However, the corneal aberration recovered to the preoperative level at one month after the operation. Presumably, these results might be due to the corneal edema of the incision site, caused by measuring the corneal thickness in the early phase of surgery.
Subject(s)
Humans , Astigmatism , Cataract , Corneal Edema , Eye , Lotus , Phacoemulsification , PupilABSTRACT
PURPOSE: To compare changes of anterior corneal aberration (Pentacam(R)) and ocular aberration (aberrometer, LADARWave(R)) after laser refractive surgery. METHODS: Sixty-six eyes underwent laser refractive surgery and were retrospectively reviewed. Anterior corneal aberration and ocular aberration were measured by Pentacam(R) and an aberrometer (LADARWave(R)) respectively. Changes of root mean square (RMS) values of coma, spherical aberration, and total high order aberration (HOA) were evaluated before, 1 month, and 3 months after surgery RESULTS: Ocular aberrations displayed low preoperative values, but after laser refractive surgery, anterior corneal aberration and ocular aberration increased equally. There were no statistically significant differences of internal optics aberration values (ocular aberration minus anterior corneal aberration) in coma, spherical aberration, and total HOA. Anterior corneal aberration and ocular aberration showed statistically significant correlations at 1 and 3 months after surgery. CONCLUSIONS: Internal optics aberration compensated the anterior corneal aberration effectively before surgery, but the increase of anterior corneal aberration after laser refractive surgery exceeded the compensation of internal optics. As a result, anterior corneal aberration and ocular aberration increased equally. The correlation between anterior corneal aberration and ocular aberration after surgery was statistically significant due to the increased proportion of anterior corneal aberration in ocular aberration.