Interocular aberration profiles in different severities of hyperopic anisometropic amblyopia / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To evaluate the interocular aberration root mean squares(RMS)characteristics among different severities of hyperopic anisometropic amblyopia.<p>METHODS: Sixty hyperopic anisometropic amblyopia were enrolled and divided into mild, moderate and severe groups. Each group was then divided into amblyopic eye(AE)and fellow eye(FE)subgroups according to the corrected visual acuity of each subject. All patients underwent wavefront analysis with iDesign^© wavefront aberration system(AMO, USA)in mydriasis condition. Paired <i>t</i>-test was used to compare interocular differences of aberration parameters within groups. <p>RESULTS: Paired<i> t</i>-test showed that significant differences in defocus equivalent(DE), BCVA between AE and FE in mild, moderate and severe anisometropic amblyopia(all <i>P</i><0.01). No significant interocular difference was noticed in mild group except for forth-order aberration RMS(<i>P</i><0.01). And No significant interocular differences were noticed in moderate and severe group except for total aberration RMS(both <i>P</i><0.01). One-way ANOVA showed that significant interocular differences were noticed in third-order aberration RMS among the groups(<i>P</i><0.01). LSD showed that interocular difference of third-order aberration RMS in moderate group was significant lower than that in mild and moderate groups(both <i>P</i><0.05). <p>CONCLUSION: In mydriasis condition, mild anisometropic amblyopia showed higher forth-order aberration RMS in AE than that in FE, moderate and sever amblyopia showed higher total aberration RMS in AE than that in FE. Moderate anisometropic amblyopia manifested lower interocular differences of third-order aberrations RMS than mild and severe amblyopia, but no significant interocular differences observed between mild and severe amblyopia.

Effect of wavefront aberration or corneal topography guided individualized LASIK on the visual quality / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To comparatively analyze the effect of wavefront aberration or corneal topography guided laser-assisted in situ keratomileusis (LASIK) on the visual quality in patients with myopia after surgery. METHODS: During the period of January 2016 to January 2017, 100 patients (a total of 200 affected eyes) with myopia in our hospital were selected as the subjects, and they were randomly divided into Group A and Group B with 50 cases in each group. Before surgery, the eyes were examined and LASIK was performed. During surgery,the corneal stroma of eyes in Group A was cut individually according to the results of wavefront aberration examination while the individual cutting in Group B was performed according to the data of corneal topography. The visual acuity and visual quality were compared between the two groups after surgery. RESULTS: There was no significant difference of the visual acuity between the two groups before surgery (P>0.05). The Log MAR uncorrected visual acuity (UCVA), Log MAR BCVA and diopter were significantly improved at 6mo after surgery (P<0.05), and the diopter of Group A at 6mo after surgery was lower than that of Group B (P<0.05). There was no significant difference of contrast sensitivity (CS) between the two groups before surgery (P>0.05). But CS of different optotypes in two groups at 3mo after surgery were all better than those before surgery (P<0. 05). There was no significant difference between the two groups in CS under the bright and non-glare condition at 3mo after surgery (P>0.05). However, CS of Group A under bright glare, dark with glare and dark without glare states were significantly better than those of Group B (P<0. 05). There was no significant difference of detection results of wavefront aberrations between the two groups before surgery(P>0 05). At 3mo after surgery, the total aberrations, total higher-order aberrations,comatic aberrations and spherical aberrations significantly increased in two groups (P<0.05), and the increase in Group A was obviously lower than that in Group B (P<0.05). CONCLUSION: Both of wavefront aberration and corneal topography guided individualized excimer surgery can significantly improve the visual acuity of patients with myopia, but the former has more advantages in improving the visual quality.

Optical performance of Toric intraocular lens rotation in Hwey-Lan Liou model eye / 中华实验眼科杂志

Background The residual astigmatism following Toric intraocular lens (IOL) rotation have received much attention.However,the variation of the optical performance and the wavefront abrrveation with Toric IOL rotation are unclear.Objective The aim of this study was to evaluate the optical performance,wavefront abrrveation and residual diopter spherical and cylinder lens with Toric IOL rotation.Methods T3,T4 and T5 Toric IOLs of +22.0 D were placed in Hwey-Lan Liou model eye respectively,with the posterior surface flat on the X axis and steep on the Y axis.Corneal astigmatism model was established by mimicing the model eye with Toric IOL using Zemax optical software.Then the Toric IOLs were rotated 5° to 10° individually under the 4 mm pupil diameter and 550 nm monochromatic light,and the image performance and wavefront abrrveation were recorded with all conditions,including modulation transfer function (MTF),out-of-focus aberration,astigmatism aberration,coma,trefoil aberration and spherical aberration.The refractive error of spherical power and cylinder power were calculated.Results Corneal astigmatism was fully corrected when Toric IOLs in the middle,and the MTF curves were near in T3,T4,T5 Toric IOLs.The image performance was worse under the high spatial frequency with the increase of rotation degrees of Toric IOLs,showing the gradually low of MTF curves,especially T5 Toric IOL.No obvious changes was seen in coma,trefoil aberration and spherical aberration after rotation of Toric IOLs,while out-of-focus aberration,astigmatism aberration were obviously increased.In addition,residual astigmatism and spherical error increase with the rotation of Toric IOLs.Conclusions Toricl IOL rotation leads to increase of astigmatism and spherical refractive error but not high order aberration.

Intrastromal crosslinking in post-LASIK ectasia / "Crosslinking" intraestromal em ectasia pós-LASIK

We describe a case of early post-LASIK ectasia detected in the first 6 months after surgery. The patient was treated by means of intrastromal corneal crosslinking under the flap, without de-epithelialization, which resulted in a positive outcome. At the time of writing, 2 years after the procedure, the patient remained free of progression.

Descrevemos um caso de ectasia de córnea precoce após cirurgia de LASIK, detectado no primeiro semestre pós-operatório. Nós optamos tratar este paciente com "crosslinking" embaixo do "flap" , sem desepitelização com bons resultados. A paciente permaneceu sem progressão da ectasia até o momento atual, dois anos após o procedimento.

Optical quality of hyperopic and myopic phakic intraocular lenses.

Aims: To assess and compare the optical quality of the myopic and hyperopic implantable collamer lens (ICL) from its wavefront aberrations for different powers and pupil diameters. Settings and Design: Prospective study. Material and Methods: The wavefront aberrations of two myopic (−3 and −6 diopters (D)) and two hyperopic V4b ICLs (+3 and +6D) were measured in vitro. To assess and compare the optical quality of different powers of ICLs, we analyzed the root mean square (RMS) of total higher order aberrations (HOAs), trefoil, coma, tetrafoil, secondary astigmatism, and spherical aberration at 3‑ and 4.5‑mm pupil. In addition, the point spread functions (PSFs) of each ICL evaluated were calculated from the wavefront aberrations at 3‑ and 4.5‑mm pupil. Statistical Analysis: A Student’s t‑test for unpaired data was used for comparison between myopic and hyperopic ICLs. Results: Myopic ICLs showed negative spherical aberration, in contrast hyperopic ICLs showed positive spherical aberration, which increases when the ICL power increases, due to the innate optical properties of the lens. All ICLs evaluated had negligible amounts of other aberrations. We did not find statistical significant differences in any Zernike coefficient RMS values analyzed between myopic and hyperopic ICLs at 3‑ and 4.5‑mm pupil (P > 0.05). Conclusions: Myopic and hyperopic ICLs provide good and comparable optical quality for low to moderate refractive error. The ICLs evaluated showed values of wavefront aberrations clinically negligible to affect the visual quality after implantation.

Ocular aberrations after wavefront optimized LASIK for myopia.

Purpose: To study the change in ocular aberrations after wavefront optimized (WFO) laser in situ keratomileusis (LASIK) for correction of myopia and to analyze causative factors that may influence them. Materials and Methods: This was a prospective case series. WFO LASIK was performed for the correction of myopia, using the hansatome (Bausch and Lomb) microkeratome to create the flap and the Allegretto laser (Wavelight Technologie) to perform the ablation. The Allegretto wave analyser (Tscherning-type) measured the ocular aberrations prior to LASIK , one month and six months postoperatively. Results: The mean age of the 59 patients included in the study was 25±5.64 years and the mean spherical equivalent of the 117 eyes that underwent LASIK was ‒5.33±1.22 preoperatively and ‒0.21±0.38 postoperatively. Hundred and two eyes of 117 (87%) achieved uncorrected visual acuity (UCVA) of 20/20 or better after WFO LASIK and 104 of 117 eyes (89%) were within ±0.5D of the attempted refractive correction. There was a 1.96-fold increase in total root-mean-square of higher order aberrations. Induced changes in seven of the 22 higher order Zernike terms showed a significant linear correlation with the refractive correction attempted. Larger ablation zones induced less spherical aberration. Conclusion: In spite of an excellent visual outcome, WFO LASIK induces significant higher order aberrations. Large ablation zones reduce the induction of spherical aberration.

Power Vector and Aberrations Using Corneal Topographer and Wavefront Aberrometer Before and After Pterygium Surgery

PURPOSE: To determine the power vector and aberrations before and after surgery for pterygium using a corneal topographer and a wavefront aberrometer. METHODS: The study group consisted of 34 eyes of 31 patients with pterygium, and were divided into two groups by pterygium size ( or = 3 mm, group II). Power vector and wavefront aberrations were evaluated using a corneal topographer (Oculus inc., Germany) and a wavefront aberrometer (LADARWAVE(R), Hartmann shack aberrometer, Alcon inc., US) at pre- and postoperative 1 week, 1 month, and 3 months. RESULTS: The preoperative blurring strength (B) and high order aberrations significantly decreased at postoperative 3 months in all groups (P or = 3 mm). To reduce aberrations and astigmatism effectively, we suggested surgical intervention in eyes with pterygia sized < 3.0 mm.

Analysis of Higher-Order Wavefront Aberrations in Standard PRK

PURPOSE: To investigate the preoperative characteristics and postoperative change of the higher-order wavefront aberrations (HOAs) in myopic photorefractive keratectomy (PRK). METHODS: Standard PRK was performed in 39 eyes (spherical equivalent -4.71+/-1.56D) using the VISX(R) STAR S4(TM) excimer laser system. Wavefront analysis was performed preoperatively and 6 months postoperatively using the VISX(R) WaveScan(TM) aberrometer. Statistical analysis was performed to assess the preoperative characteristics of the HOAs and the PRK-induced aberrations. RESULTS: The preoperative root mean square (RMS) value of the total HOAs was 0.291 micrometer: coma 0.159 micrometer, trefoil 0.157 micrometer, spherical aberration 0.093 micrometer. Among the 3 HOAs, only the spherical aberration showed moderate magnitude negative correlation with the spherical equivalent (p=0.012) and sphere (p=0.005). The magnitude of all of the HOAs, except trefoil, were significantly increased at postoperative 6 months: total HOAs 183% (0.533 micrometer, p<0.001), spherical aberration 341% (0.317 micrometer, p<0.001), coma 185% (0.294 micrometer, p<0.001), trefoil 104% (0.163 micrometer, p=0.681). In the postoperative correlation analysis, only the PRK-induced spherical aberration showed the increase of magnitude with increasing preoperative spherical equivalent (p=0.036) and sphere (p=0.019). CONCLUSIONS: The HOAs, especially spherical aberration and coma, were increased after PRK. Among the 3 HOAs, the spherical aberration showed the greatest increase of magnitude and percent change; it also showed a positive correlation with increasing preoperative spherical equivalent and sphere. Further software improvements in the wavefront-guided surface ablations need to have a diminution of PRK-induced spherical aberration.