Single-step transepithelial photorefractive keratectomy in high myopia: qualitative and quantitative visual functions

AIM: To investigate quantitative and qualitative optical outcomes of single-step transepithelial photorefractive keratectomy (TransPRK) in high myopia. METHODS: In a prospective interventional case-series, 30 eyes with high myopia (-6.00 to -8.75 D) with (up to -3.00 D) or without astigmatism were enrolled from Bina Eye Hospital, Tehran, Iran. One-step TransPRK was performed with aberration-free aspherical optimized profile and SCHWIND AMARIS 500 laser. One-year follow-up results for refraction, visual acuities, vector analysis, ocular wave-front (OWF) and corneal wave-front (CWF) higher order aberrations (HOA), contrast sensitivity (CS), and post-operative haze were assessed. RESULTS: After the surgery, both photopic and mesopic CSs significantly improved (both P<0.001). We detected significant induction of OWF coma and trefoil (P<0.001 for both) HOAs; CWF coma (P=0.002), spherical (P<0.001), and tetrafoil (P=0.003) HOAs in 6 mm analysis diameter; and CWF trefoil (P=0.04) HOA in 4 mm analysis diameter. The range of mean induction observed for various HOAs was 0.005-0.11 µm. The 86.7% of eyes reached an uncorrected distance visual acuity of 20/20 or better; 96.7% of eyes were within ±0.5 D of targeted spherical refraction. In vector analysis, mean correction index value was 1.03 and mean index of success was 0.22. By 12mo after the operation, no eye lost any number of corrected distance visual acuity lines. We detected no corneal haze greater than 1+ throughout the follow-up. CONCLUSION: Our findings show promising effects of single-step TransPRK on quality of vision in high myopic eyes. It also improves refraction and visual acuity.     

年龄相关性白内障的高阶像差及光学质量

目的：比较年龄相关性白内障患者和正常人的高阶像差及光学质量差异。方法：病例对照研究。选取2013 年10 月至2014 年7 月在中南大学湘雅医院拟行白内障超声乳化摘除联合人工晶状体植入术的年龄相关性白内障患者27例（36眼）作为白内障组；另选择正常透明晶状体的患者家属17例（30眼）作为正常对照组。对3.0 mm瞳孔直径下矫正到最佳视力时白内障组与正常对照组的眼内、角膜、全眼的3阶、4阶高阶像差及光学质量参数斯特列尔比值（SR）、各空间频率段调制传递函数（MTF）等，采用两独立样本t检验进行比较分析。结果：白内障组与正常对照组之间等效球镜度（SE）、角膜曲率、角膜非球面参数Q值差异均无统计学意义。白内障组眼内及全眼总高阶像差均方根值（RMS）高于正常对照组（t=8.073、7.321，P < 0.001），白内障组眼内及全眼3阶、4阶各项高阶像差均明显高于正常对照组（P < 0.001），2 组之间角膜总高阶像差差异无统计学意义。白内障组眼内及全眼SR值均低于正常对照组（t=10.635、9.039，P < 0.001），但2 组之间角膜SR值差异无统计学意义。白内障组眼内及全眼MTF值均低于正常对照组，差异均有统计学意义（t=8.325、7.034，P < 0.001），2 组之间角膜MTF值差异无统计学意义。结论：白内障患者眼内及全眼SR值、MTF值明显低于正常人，眼内及全眼总高阶像差较正常人明显增加，但是角膜总高阶像差、SR值、MTF值与正常人无差异。     

Quality of vision and graft thickness in deep anterior lamellar and penetrating corneal allografts

PURPOSE: To compare visual function after deep anterior lamellar keratoplasty (DALK) with visual function after penetrating keratoplasty (PK) for keratoconus and correlate this with corneal thickness. DESIGN: Retrospective case series. METHODS: Twenty-three patients (32 eyes) with unilateral or bilateral DALK or PK for keratoconus were analyzed for visual quality after suture removal. Evaluation included measurement of visual acuity, contrast sensitivity, and higher order aberrations (HOAs) (WaveScan; Visx, Santa Clara, California, USA). Readings were performed with both spectacle and rigid contact lens correction of refractive error. Total and residual stromal thickness after DALK was measured using optical coherence tomography (OCT) and correlated to visual quality. RESULTS: Eyes after PK had better visual acuity than eyes after DALK (P = .018). Subgroup analysis of DALK eyes revealed that the level of visual acuity was related to the thickness of residual recipient corneal stroma. Eyes with a recipient corneal bed thickness of <20 microm had visual acuities similar to eyes with a PK, whereas those with a recipient thickness of >80 microm had a significantly reduced visual acuity (P = .0009). Contrast sensitivity was similar in DALK and PK eyes. There was no significant difference in HOAs between eyes with DALK or PK. CONCLUSIONS: These data suggest that the main parameter for good visual function after DALK for keratoconus is the thickness of residual recipient stromal bed. An eye with a DALK with a residual bed of <20 microm can achieve a similar visual result as a PK.     

Advanced corneal surface ablation efficacy in myopia: changes in higher order aberrations

Objective: To evaluate the change of ocular and corneal higher order aberrations (HOAs) after wavefront-guided advanced surface ablation (WF-ASA) for myopia using 4 different epithelial management techniques (AA-PRK, LASEK, Epi-PRK, and Epi-LASIK).Design: Retrospective single centre excimer database analysis.Participants: Two hundred and forty eyes equally divided between the 4 WF-ASA techniques, matched for mean and range of required spherical correction.Methods: Ocular wavefront aberrations were measured using the wavescan aberrometer and corneal aberrations were obtained from corneal topography elevation maps and calculated by ray-tracing. All data were collected preoperatively and 3 months following treatment. The aberrations were described as Zernike polynomials, and analysis focused on total HOAs and spherical aberration (SA).Results: Three months postoperatively, there was a statistically significant surgically induced increase in total HOAs and SA both for ocular and corneal analysis (p < 0.001). There was no statistically significant difference in the induced ocular SA and HOAs between the groups, but the differences in induced corneal SA and HOAs were significant (p = 0.010). Ocular changes in SA were weakly correlated to preoperative SA (−0.30, p < 0.001) but strongly correlated to applied spherical correction (−0.68, p < 0.001). Surgically induced corneal SA was weakly correlated to preoperative corneal SA (−0.34, p < 0.001) and applied spherical correction (−0.46, p < 0.001).Conclusions: Three months postoperatively, all procedures resulted in an increase in ocular and corneal HOAs and SA. Induced aberrations were most strongly correlated to the applied spherical power correction. Modifying the existing ablation pattern to compensate for induced HOAs might improve the outcome.     

A 3-month comparison study of subjective and objective visual quality of small incision lenticule extraction and transepithelial photorefractive keratectomy in patients with low and moderate myopia

AIM: To compare the subjective and objective visual quality between small incision lenticule extraction (SMILE) and transepithelial photorefractive keratectomy (tPRK) in patients with low and moderate myopia. METHODS: Patients undertaking SMILE or tPRK for the correction of low and moderate myopia were consecutively recruited in this prospective cohort study with a 3-month follow-up period. Objective evaluation [visual acuity test, manifest refraction, wavefront aberrations, the total cut-off value of the total modulation transfer function (MTFcut-off), and Strehl ratio (SR)] and subjective evaluation of visual quality (quality-of-life questionnaire) were conducted before surgery and at days 1, 7, 30, and 90 after surgery. RESULTS: A total of 47 patients (94 eyes) with SMILE and 22 patients (22 eyes) with tPRK were enrolled. The uncorrected visual acuity (UCVA) was better in SMILE patients on day 7 after surgery (1.13±0.13 vs 0.99±0.17, t=4.85, P<0.001) but was comparable at days 30 and 90. At day 90, the SMILE group had a lower spherical equivalent (SE) than the tPRK group (0.04±0.31 vs 0.19±0.43, t=2.08, P=0.042). Total higher order aberrations (HOAs) were induced in both surgical types, which were more evident in the tPRK group with 3-mm pupil diameter (0.16±0.07 vs 0.11±0.05, t=4.27, P<0.001) and 5-mm pupil diameter (0.39±0.17 vs 0.36±0.11, t=2.33, P=0.022). The MTFcut-off and SR showed a trend of improvement in both SMILE and tPRK patients but were statistically better in the SMILE group with both pupil diameters. There was a significant improvement of contrast sensitivity (CS) over baseline levels at the spatial frequency of 18 cycles/degree (c/d) in the SMILE group (F=2.72, P=0.033) and at 3 c/d (F=3.03, P=0.031), 12 c/d (F=3.72, P=0.013), and 18 c/d (F=4.62, P=0.004) in the tPRK group. The subjective quality of life questionnaire showed a steady improvement in the SMILE group (F=8.31, P<0.001) but not the tPRK group. CONCLUSION: SMILE and tPRK are both safe and effective ways to correct low and moderate myopia. A generally better and quicker recovery of visual quality favors the application of SMILE in qualified patients.     

Corneal densitometry and biomechanical properties in patients with primary congenital glaucoma

ObjectiveTo describe corneal densitometry, topographic measurements, and biomechanical properties in patients with primary congenital glaucoma (PCG) and healthy patients. To examine correlations between variables and determine their glaucoma diagnostic capacity.MethodsThis was a cross-sectional, case-control study conducted in 50 eyes of 50 patients with PCG (G1) and 40 eyes of 40 healthy patients (G2). The variables determined in each participant were: intraocular pressure, best corrected visual acuity (BCVA), corneal densitometry, topographic data using the Pentacam HR-Scheimpflug imaging system (Oculus Optikgerate GmbH, Wetzlar, Germany), and corneal hysteresis (CH) and corneal resistance factor (CRF) using the Ocular Response Analyzer (Reichert Ophthalmic Instruments, Depew, NY).ResultsOverall densitometry was significatively higher in the PCG group (G1: 17.94 ± 4.99 vs G2: 13.25 ± 1.96, p < 0.001). CH (G1: 8.02 ± 11.35 vs G2: 11.35 ± 1.42, p < 0.001) and CRF (G1: 9.48 ± 2.83 vs G2: 10.77 ± 1.34, p < 0.001) were lower in the glaucoma group. Mean posterior, central, and anterior elevation and mean keratometry were higher in G1 (p < 0.05). In the PCG group, overall densitometry showed significant correlation with CH (r = –0.321, p = 0.028) and with BCVA (r = −0.498, p = 0.002). AUCs (areas under the curve) for CH and overall densitometry were high (0.839 and 0.899 respectively) and the best overall densitometry; CH and CRF cutoffs were 14.0, 9.3 and 9.2 respectively.ConclusionDensitometry is increased, and biomechanical corneal properties are decreased in patients with PCG. Densitometry and visual acuity showed a negative and significant correlation, so this measurement could be used as an indirect parameter of BCVA in the clinical practice.     

Tear cytokine levels in the diagnosis and severity assessment of ocular chronic graft-versus-host disease(GVHD)

PurposeTo analyse the tear cytokine levels of patients diagnosed with ocular chronic graft-versus-host disease(GVHD)and examine the consistency of these levels with different ocular surface parameters.Methods23 ocular chronic GVHD patients were selected for the assessment of tear cytokine levels and ocular surface parameters (TBUT, CFS, OSDI, and Schirmer's test), and 16 dry eye disease(DED)patients without systemic immune disease were selected as the control group. The 23 cytokines were measured using microsphere-based immunoassay analysis and their consistency with different ocular surface parameters was studied.ResultsICAM-1, IL-1β, IL-6, and IL-8 showed elevated levels in the eyes of oGVHD patients compared to DED [P < 0.001]. IL-7 and EGF showed lower levels in the eyes of patients with oGVHD than in those of patients with DED [P < 0.0001]. Furthermore, the levels of IL-6 and IL-8 showed a stronger correlation with corneal fluorescein staining (CFS) (P < 0.05), and the levels of IL-6 and ICAM-1 were most consistent with fluorescein tear film break-up time (TBUT) (P < 0.05).ConclusionsOur study demonstrated certain tear cytokines, including ICAM-1, IL-1β, IL-6, IL-8 IL-7 and EGF, as promising new possible diagnostic markers of chronic oGVHD and criteria for chronic ocular GVHD severity. Because tear sampling is noninvasive and simple, this method is expected to be an overwhelming applicable for the screening and diagnosis of chronic GVHD.     

角膜和全眼高阶波前像差的特点及年龄相关性变化的研究

目的 研究人眼角膜和全眼单色高阶波前像差特点及年龄相关性变化.方法 使用Tracey-iTrace视觉功能分析仪测量113只正常国人眼计59人,年龄5～73岁,平均(33.81±20.50)岁,角膜和全眼的球差(Z40)、总高阶像差(HOAs)、总彗差(TC)、总球差(TS)、总三叶草像差(TT).并对角膜和全眼高阶波前像差进行年龄相关性分析.结果 角膜Z40的均方根系数值平均为(0.27±0.07)μm(0.130～0.451)μm,虽然角膜Z40随年龄略呈增加趋势,但无统计学意义(r=0.172,p=0.069).全眼的Z40随年龄增加而增加(r=0.545,p=0.000).角膜的HOAs(r=0.499,p=0.000)、TC(r=0.149,p=0.021)、TT(J=0.344,p=0.000)和全眼的HOAs(r=0.427,p=0.000)、TC(r=0.253,p=0.007)、TT(r=0.185,p=0.050)均随年龄的增加而增加.角膜HOAs、TC、,TT.与全眼相对应像差呈正相关(r=0.327,p=0.000;r=0.233,p=0.013;r=0.481,p=0.000).角膜TS不随年龄而变化(r=0.180,p=0.057),但全眼的TS随年龄的增加而增加(r=0.560,p=0.000).结论 国人角膜的HOAs、Tc、1Tr随年龄的增加而增加,并导致了全眼的上述波前像差随年龄的增加而增高.角膜的TS和Z40不随年龄发生明显变化,全眼的TS和Z40随年龄增加是由于晶状体总球差和球差随年龄增加的结果.国人角膜球差具有较大个体差异性,手术前角膜球差的测量是非球面IOL选择的必要步骤.     

配戴角膜矫形镜对角膜形态和单色光波阵面像差的影响

目的探讨角膜矫形镜对角膜形态和单色光波阵面像差的影响,评价角膜形态的改变对眼球光学性能的影响。方法 选择近视眼志愿者25例(50只眼),屈光不正等效球镜度数为-1.75--4.75D,受检眼均在配戴前进行裂隙灯显微镜检查、最佳矫正视力的检查、角膜地形图检查和单色光波阵面像差测量。受检者夜戴镜片至少7 h,配戴后1 d、1、2、4、8、12周晨起戴镜片检查,详细记录配戴者戴镜的天数和夜戴的时间。分别进行裂隙灯显微镜检查、最佳矫正视力检查、角膜地形图检查,12周后随访检查再次作单色光波阵面像差的测量。结果受检者戴镜前的矫正视力为-0.0628±0.0286(LogMAR),而戴角膜矫形镜12周后的矫正视力为-0.0120±0.0318,两者比较差异有显著意义(F=17.821,P<0.001);戴镜前单色光波阵面像差Zernike函数值的均方根RMS(Root-Mean-Square)为(0.5766±0.4771)μm,而戴镜90 d后单色光波阵面像差Zernike函数值的均方根RMS值为(1.3731±0.8039)μm,两者比较差异有显著意义(F=36.513,P<0.001),与各级像差相关的Zernike函数值的RMS值均增加;角膜地形前表面偏心率下降,但后表面偏心率增加。结论降低近视度数的角膜矫形镜可引起患者视觉质量的下降。角膜矫形镜配戴后角膜形态改变引起的单色光波阵面像差增大可能是视觉质量降低的     

经上皮准分子激光角膜表面切削术（TransPRK）对角膜光密度与角膜高阶像差的影响

目的　观察经上皮准分子激光角膜表面切削术（transepithelial photorefractive keratectomy,TransPRK）对角膜光密度与角膜高阶像差的影响,并分析二者的相关性。方法　选取于2017年3月至7月在新乡医学院第一附属医院眼科行TransPRK治疗近视及近视散光的患者80例,均选取右眼纳入研究。对比患眼术前与术后1个月、3个月、6个月角膜光密度与高阶像差的变化情况。术前与术后不同时间点差异的比较采用LSD-t检验,角膜光密度和高阶像差之间的相关性应用Pearson相关分析。结果　在TransPRK术后1个月、3个月、6个月以角膜顶点为中心≤2 mm、＞2~6 mm和＞6~10 mm区域内角膜光密度均较术前明显增高,差异均有统计学意义（均为P＜0.05）。术后1个月、3个月、6个月,总高阶像差、彗差、球差均较术前明显升高,差异均有统计学意义（均为P＜0.05）;三叶草像差在术后1个月、3个月与术前相比差异均有统计学意义（均为P＜0.05）;二级散光差在术后1个月与术前相比差异有统计学意义（P＜0.05）。术后3个月以角膜顶点为中心≤2 mm区域内角膜光密度的变化值与球差的变化值存在负相关性（r=-0.252,P=0.024）。以角膜顶点为中心＞2 ~6 mm区域内角膜光密度变化值与总高阶像差、彗差的变化值均存在正相关性（r=0.403、0.567,均为P=0.000）;与球差的变化值存在负相关性（r=-0.607,P=0.000）。术后6个月时以角膜顶点为中心≤2 mm区域内角膜光密度的变化值与球差的变化值存在负相关性（r=-0.257,P=0.021）;以角膜顶点为中心＞2 ~6 mm区域内角膜光密度变化值与彗差的变化值存在正相关性（r=0.244,P=0.029）,与球差的变化值存在负相关性（r=-0.374,P=0.001）。结论　角膜光密度可以作为评判角膜健康情况的定量客观指标,其可以评估TransPRK术后患者角膜的恢复情况,并且预测或者提示术后高阶像差的变化。     

Impact of Forward and Backward Scattering and Corneal Higher-Order Aberrations on Visual Acuity after Penetrating Keratoplasty

Purpose: To assess the relationship of forward and backward scattering and corneal higher-order aberrations (HOAs) with corrected distance visual acuity (CDVA) after penetrating keratoplasty (PK). Methods: This retrospective study comprised 25 eyes of 25 consecutive patients who underwent PK using the VisuMax femtosecond laser system and age-matched 25 eyes of 25 healthy subjects. We quantitatively assessed objective scattering index (OSI) using the double-pass instrument (OQAS II, Visiometrics), corneal densitometry (CD) and corneal HOAs with the Scheimpflug rotating camera (Pentacam HR, Oculus) 1 year postoperatively. Results: The OSI, CD, and corneal HOAs were significantly larger in the PK group than those in the control group (p ≤ 0.011). We found significant correlations of logMAR CDVA with the OSI (r = 0.477, p = 0.016), and with the anterior, posterior, and total corneal HOAs of the central 4-mm zone (anterior: r = 0.573, p = 0.003, posterior: r = 0.596, p = 0.002, total: r = 0.472, p = 0.017), but no significant association with the CD of the 0–2 mm zone at any layers (anterior: r = 0.236, p = 0.257, center: r = 0.139, p = 0.506, posterior: r = 0.073, p = 0.728, total: r = 0.212, p = 0.308). Similar results were obtained when the analysis was repeated with corneal HOAs of the central 6-mm zone and CDs in 2–6 mm zone. Conclusions: Our pilot study demonstrated that the postoperative CDVA was significantly correlated with OSI and corneal HOAs, but not with backward scattering in post-PK eyes, suggesting that OSI as well as corneal HOAs plays an essential role in postoperative visual performance after PK.     

两种回归方法推算扫描视觉诱发电位客观推断视力的比较

背景扫描视觉诱发电位（SVEP）是一种客观视力的检测方法,虽然SVEP客观推断视力与主观视力之间存在着明显的相关性,但是两者之间并不完全吻合。研究显示,改进SVEP客观推断视力的推算方法可以提高推断视力的准确性。目的研究SVEP客观推断视力两种推算方法,即振幅-空间频率（A—SP）回归方法与振幅一视角对数（A-logVA）回归方法在客观视力评估中的准确性,探讨影响SVEP客观推断视力准确性的因素。方法对64例具有不同视力的113眼进行SVEP检测、主观小数视力和LogMAR视力检测,分别计算A—SP回归方法推算出的小数视力和LogMAR视力及A．10gVA回归方法推算出的小数视力和LogMAR视力,并对检测结果行相关性分析。使用重庆国特公司GT-2000n型视觉电生理仪检测SVEP,选用0．99～12．89cpd的10个空间频率水平正弦光栅连续刺激视网膜,经离散傅里叶分析获得A—SP回归曲线和A—logVA回归曲线,并将相关直线外推至0振幅处,获得SVEP客观推断视力。结果在小数视力评价系统中,A—SP回归方法和A-logVA回归方法推算出的回归线相关指数分别为0．663和0．705,主观小数视力与由A-SP回归方法推算所得的小数视力间呈正相关（r=0．620,P〈0．01）,主观小数视力与由A—logVA回归方法推算所得的小数视力间呈正相关（r=0．540,P〈0．01）。SP小数视力与VA小数视力间差异有统计学意义（Z=-8．688,P〈0．01）;在LogMAR视力评价系统中,A-SP回归方法和A—logVA回归方法推算出的回归线相关指数分别为0．733和0．715,主观LogMAR视力与由A-SP回归方法推算所得的LogMAR视力间呈正相关（r=0．710,P〈0．01）,主观LogMAR视力与由A-logVA回归方法推算所得的LogMAR视力间呈正相关（r=0．700,P〈0．01）。两种推算方法获得的LogMAR视力间差异有统计学意义（Z=-8．748,P〈0．01）。不同性别、眼别、病种以及年龄段中VALogMAR视力测试值的偏差差异均无统计学意义（χ2=2．171,P=0．338;χ2=0．976,P=0．614;χ2=6．032,P=0．420;χ2=14．720,P=0．257）。结论SVEP是检测客观视力较为有效的方法。但SVEP变异较大,就目前检测技术的稳定性与准确性而言,A—logVA回归方法推算出的客观视力较A—SP回归方法准确。     

Ocular higher-order aberrations and contrast sensitivity after conventional laser in situ keratomileusis

PURPOSE: To investigate prospectively the relation between induced changes in higher-order aberrations of the eye and changes in contrast sensitivity by conventional laser in situ keratomileusis (LASIK) for myopia. METHODS: In 200 eyes of 110 consecutive patients (mean age, 32.7 +/- 8.4 years) undergoing LASIK, ocular aberrations and contrast sensitivity function were determined before and 1 month after surgery. The amount of myopic correction was 5.2 +/- 2.8 D (range, 1.0-13.0). Ocular higher-order aberrations were measured for a 4-mm pupil using the Hartmann-Shack wavefront analyzer (KR-9000PW; Topcon, Tokyo, Japan). The root mean square (RMS) of the third- and fourth-order Zernike coefficients was used to represent coma- and spherical-like aberrations, respectively. Total higher-order aberrations were calculated as the RMS of the third- and fourth-order coefficients. Contrast sensitivity and low-contrast visual acuity were measured. From the contrast sensitivity data, the area under the log contrast sensitivity function (AULCSF) was calculated. RESULTS: LASIK significantly improved logMAR best corrected visual acuity (Wilcoxon signed-rank test, P <0.001), but significantly reduced AULCSF (P <0.001) and low-contrast visual acuity (P=0.007). Total higher-order (P <0.001), coma-like (P <0.001), and spherical-like (P <0.001) aberrations were significantly increased after LASIK. The greater the amount of achieved myopia correction was, the more the changes in contrast sensitivity function and ocular higher-order aberrations were. The induced changes in AULCSF by LASIK showed significant correlations with changes in total higher-order (Pearson r=-0.221, P=0.003), coma-like (r=-0.205, P=0.006), and spherical-like (r=-0.171, P=0.022) aberrations. The changes in logMAR low-contrast visual acuity by surgery significantly correlated with changes in total higher-order (r=0.222, P=0.003), coma-like (r=0.201, P=0.007), and spherical-like (r=0.207, P=0.005) aberrations. CONCLUSIONS: Conventional LASIK significantly increases ocular higher-order aberrations, which compromise the postoperative contrast sensitivity function.     

Efficacy of scleral-fixated 3-looped haptics intraocular lens implantation for surgical management of microspherophakia

AIM: To evaluate the safety and efficacy of scleral-fixated 3-looped haptics intraocular lens (IOL) implantation for surgical management of microspherophakia. METHODS: A retrospective case series include 10 microspherophakic patients (15 eyes) who underwent lens removal plus a modified surgical treatment of scleral-fixated 3-looped haptics IOL implantation. The primary outcomes involved visual acuity, intraocular pressure (IOP). Secondary outcomes were spherical equivalent (SE), anterior chamber depth (ACD), corneal endothelial cell density and postoperative complications. RESULTS: After a postoperative follow-up of 17.60±15.44mo, improved visual outcomes can be observed. The uncorrected distance visual acuity (UCVA) logMAR improved from 1.54±0.59 preoperatively to 0.51±0.35 postoperatively (P=0.001), and best corrected visual acuity (BCVA) logMAR improved from 0.97±0.91 preoperatively to 0.24±0.23 postoperatively (P=0.003). Moreover, the SE decreased from -9.58±7.47D preoperatively to -0.65±2.21 D postoperatively (P<0.001). In terms of safety profile, the average IOP decreased from 21.10±12.94 mm Hg preoperatively to 14.03±3.57 mm Hg postoperatively (P=0.044), and the previously elevated IOP of three eyes decreased to the normal range. The ACD increased from 2.25±1.45 mm preoperatively to 3.35±0.39 mm postoperatively (P=0.017). The density of corneal endothelial cells did not change significantly after surgery (P=0.140). The posterior chamber IOLs were well centered and no severe complications were found. CONCLUSION: Lens removal plus the modified surgical treatment of scleral-fixated 3-looped haptics IOL implantation can help in improvement of visual acuity, which can be regarded as a relative safe method for the surgical management of microspherophakia.     

Superficial keratectomy: indications and outcomes

Introduction

To evaluate the indications and outcomes of manual blade superficial keratectomy

Serial measurements of higher-order aberrations after blinking in patients with dry eye

PURPOSE: To study the sequential postblink changes in ocular higher-order aberrations (HOAs) in patients with dry eye. METHODS: A wavefront sensor was used to measure HOAs sequentially for 30 seconds in 20 eyes of 20 patients with dry eye. The 20 eyes were classified into two groups, with or without superficial punctate keratopathy (SPK) in the central cornea. During the measurement, subjects were required to blink every 10 seconds. The aberration data were analyzed in the central 4-mm diameter for coma-like, spherical-like, and total HOAs up to sixth-order Zernike polynomials. Total HOAs, as well as fluctuation index (FI) and stability index (SI) of the total HOAs over time were compared between the two groups. The sequential changes in coma-like aberration, spherical-like aberration, and total HOAs were also investigated. RESULTS: The total ocular HOAs were significantly (P = 0.001) greater in dry eyes with central SPK than in dry eyes without central SPK. The sequential pattern of the total ocular HOAs had higher initial and consistently higher values in dry eyes with central SPK, whereas that of dry eyes without central SPK showed consistently lower total HOAs that were similar to the pattern of normal eyes. CONCLUSIONS: Increased HOAs in dry eye at least partially result from SPK above the optical zone. The low tear volume in dry eye may not cause sequential increases in HOAs after blinking. Sequential measurement of HOAs may be useful for evaluating the sequential changes in optical quality in patients with dry eye.     

【In Press】Comparison of myopia control between toric and spherical periphery design orthokeratology in myopic children with moderate-to-high corneal astigmatism

AIM: To compare clinical results between toric and spherical periphery design orthokeratology (ortho-k) in myopic children with moderate-to-high corneal astigmatism. METHODS: This retrospective study enrolled 62 eyes of 62 subjects using toric ortho-k lenses. These subjects were assigned to the toric group. Based on the one-to-one match principle (same age, proximate spherical equivalent and corneal astigmatism), 62 eyes of 62 subjects were enrolled and included in the spherical group. At one-year follow-up visit, visual acuity, corneal astigmatism, treatment zone decentration, axial elongation and adverse reaction were compared between these two groups. RESULTS: At the one-year visit, corneal astigmatism was significantly lower in the toric group (1.22±0.76 D) than in the spherical group (2.05±0.85 D) (P=0.012). The mean magnitude of the treatment zone decentration was 0.62±0.42 mm in the toric group and 1.07±0.40 mm in the spherical group (P=0.004). Axial elongation was significantly slower in the toric group (0.04±0.13 mm) than in the spherical group (0.09±0.13 mm) (P=0.001). The one-year axial elongation was significantly correlated with initial age (r=-0.487, P<0.001) and periphery design of ortho-k lens (r=0.315, P<0.001). The incidence of corneal staining was lower in the toric group (8.1%) than in the spherical group (19.4%) (P<0.001). CONCLUSION: Toric periphery design ortho-k lenses may provide lower corneal astigmatism, better centration, slower axial elongation and lower incidence of corneal staining in myopic children with moderate-to-high corneal astigmatism.     

Comparison of myopia control between toric and spherical periphery design orthokeratology in myopic children with moderate-to-high corneal astigmatism

AIM: To compare clinical results between toric and spherical periphery design orthokeratology (ortho-k) in myopic children with moderate-to-high corneal astigmatism. METHODS: This retrospective study enrolled 62 eyes of 62 subjects using toric ortho-k lenses. These subjects were assigned to the toric group. Based on the one-to-one match principle (same age, proximate spherical equivalence and corneal astigmatism), 62 eyes of 62 subjects were enrolled and included in the spherical group. At one-year follow-up visit, visual acuity, corneal astigmatism, treatment zone decentration, axial elongation and adverse reaction were compared between these two groups. RESULTS: At the one-year visit, corneal astigmatism was significantly lower in the toric group (1.22±0.76 D) than in the spherical group (2.05±0.85 D) (P=0.012). The mean magnitude of the treatment zone decentration was 0.62±0.42 mm in the toric group and 1.07±0.40 mm in the spherical group (P=0.004). Axial elongation was significantly slower in the toric group (0.04±0.13 mm) than in the spherical group (0.09±0.13 mm) (P=0.001). The one-year axial elongation was significantly correlated with initial age (r=-0.487, P<0.001) and periphery design of ortho-k lens (r=0.315, P<0.001). The incidence of corneal staining was lower in the toric group (8.1%) than in the spherical group (19.4%) (P<0.001). CONCLUSION: Toric periphery design ortho-k lenses may provide lower corneal astigmatism, better centration, slower axial elongation and lower incidence of corneal staining in myopic children with moderate-to-high corneal astigmatism.     

Anterior segment optical coherence tomography-guided transepithelial phototherapeutic keratectomy for scarring of the central cornea following pterygium excision

AIM: To evaluate the efficacy and safety of ruthenium-106 (106Ru) plaque radiotherapy at a dose (>50 Gy) higher than recommended (29~50 Gy) for treatment of circumscribed choroidal hemangioma (CCH) in Chinese patients. METHODS: This retrospective study included 25 symptomatic CCH patients undergoing 106Ru plaque brachytherapy involving 25 eyes between January 2005 and August 2016. Ophthalmic examination was performed at the baseline and at each post-treatment follow-up visit, using best-corrected visual acuity (BCVA), dilated fundus examination, and B-scan ultrasonography. The primary efficacy outcome measures included the changes in BCVA and hemangioma dimensions at the last followup visit from the baseline. RESULTS: The mean followup duration was 28.0 ± 26.6 (range, 12-110) months. All the hemangiomas were located in the posterior pole except for two involving the fovea. The mean apex dose of 106Ru plaque radiotherapy was 84.4 ± 19.7 Gy. The mean BCVA improved from 41.4 ±29.3 (0-97) at the baseline to 53.0 ± 33.8 (0-97) ETDRS letters at the last visit (P=0.01). The mean hemangioma height declined from 3.98 ± 0.88 (2.40-5.50) mm to 0.84 ± 1.63 (0-6.47) mm (P≤0.001), and the greatest linear diameter (GLD)reduced from 9.36 ± 2.23 mm (6.80-15.00) to 7.40 ± 2.45 (0-13.00) mm (P≤0.001). Hemangioma size increased in one (4%) eye with a worsened vision, and subretinal fluid completely resolved in all but one patient (4%). Radiation-related retinopathy was observed in two patients at post-treatment 9 and 11 months, respectively. CONCLUSION: 106Ru plaque brachytherapy at a dose (>50 Gy) higher than recommended (29~50 Gy) is an effective treatment regimen for symptomatic CCH associated with significantly improved visual acuity and a favorable safety profile in Chinese patients.     

Fourier analysis of corneal astigmatic changes following photorefractive keratectomy

The purpose of this study was to evaluate the corneal irregular astigmatism following photorefractive keratectomy (PRK) for myopia. The corneal topography of 30 eyes of 26 patients was measured with the TMS-1 videokeratoscope before and 1 month after PRK. Axial dioptric data were decomposed into four components; A0 (Sphericity), C1 × 2 (Asymmetry), C2 × 2 (Regular astigmatism), and C3 (higherorder irregularity) for the central 3 and 6 mm zone by Fourier series harmonic analysis. Post-operative topographies were divided into those with an irregular and those with a homogeneous pattern, and the Fourier components were compared. In the 6mm zone, A0 was significantly decreased (P &lt; 0.001), and C1 × 2, C2 × 2, and C3 were significantly increased (P = 0.001, 0.005, 0.002, respectively). In the 3mm zone, A0 decreased (P &lt; 0.001) and C1 × 2 increased (P &lt; 0.001) significantly. C1 × 2 was correlated with the post-operative corrected visual acuity (P &lt; 0.001, r = 0.647). The irregular pattern group had a larger C1 × 2 component (P &lt; 0.001). The treatment displacement was not correlated with any component. In conclusion, irregular topography due to intraoperative drift or asymmetrical wound healing may play a more important role in the post-operative corneal optical property than mild treatment displacement.