便携式电脑验光仪筛查屈光不正的可行性探讨

目的 探讨便携式电脑验光仪的准确性及用其筛查屈光不正的可行性.设计诊断试验.研究对象2008年6月至9月南通大学附属医院眼科就诊的屈光不正患者65例（130眼）.方法 对所有病例分别行SHIN-NIPPON SRH-2000便携式电脑验光仪验光及视网膜检影.主要指标屈光值（球镜度数、柱镜度数及轴向）的差异性检验、相关分析及受试者工作特征（ROC）曲线分析.结果 以视网膜检影为金标准,电脑验光的球镜度数轻度偏正,其中睫状肌麻痹后电脑验光与检影的差值为（＋0.33±0.56）D,呈高度正相关（r=0.98,P〈0.01）,差异有统计学意义（t=6.87,P〈0.01） 电脑验光的柱镜度数轻度偏负,其中睫状肌麻痹后电脑验光与检影的差值为（-0.23±0.45）D,呈中度正相关（r=0.81,P〈0.01）,差异有统计学意义（t=-5.85,P〈0.01）.电脑验光在睫状肌麻痹前后比较无统计学差异（球镜度数t=1.31,P=0.26 柱镜度数t=-0.28,P=0.78）.电脑验光对散光的检出率高,但主要是≤0.75D的低度散光,且与视网膜检影的轴向差值多数≤150.以视网膜检影的等效球镜为参考指标,电脑验光的ROC曲线下面积〉0.95（睫状肌麻痹后为0.984,睫状肌麻痹前为0.979）.结论 便携式电脑验光仪筛查屈光不正的准确性与视网膜检影一致,可用在群体眼病流行病学调查中筛查屈光不正.     

Comparison of refractive outcomes using five devices for the assessment of preoperative corneal power

Background: To compare keratometric values obtained with a manual keratometer (Topcon), an automated keratometer (Canon), an Orbscan II (Bausch & Lomb), the IOLMaster keratometer (Carl‐Zeiss) and the Pentacam rotating Scheimpflug camera (Oculus) in cataract surgery, and to characterize the refractive outcomes generated using each device. Design: Retrospective study conducted at a tertiary university hospital. Participants: Sixty‐nine eyes of 69 patients were analysed. Methods: The keratometric values obtained with different devices (manual keratometer, automated keratometer, corneal topography, IOLMaster keratometer and Scheimpflug camera) were employed for intraocular lens power calculation. Multiple comparisons of averaged keratometric value were conducted, and the averaged keratometric value was used to calculate the predicted refraction. The absolute values of corneal astigmatism were calculated and also compared. Main Outcome Measures: Mean keratometric value, absolute value of astigmatism, mean error and mean absolute error from each device. Results: The mean keratometric values generated by manual keratometer, automated keratometry, corneal topography, IOLMaster keratometer and the Pentacam Scheimpflug system were 43.95 ± 1.39, 43.91 ± 1.39, 44.67 ± 1.53, 44.03 ± 1.41 and 42.96 ± 1.39 diopter, respectively. The absolute value of astigmatism determined via manual keratometer, automated keratometer, corneal topography, IOLMaster keratometer and the Pentacam Scheimpflug system were 0.95 ± 0.60, 0.99 ± 0.69, 1.14 ± 0.74, 1.11 ± 0.65 and 1.03 ± 0.73 diopter, respectively. The corneal topography showed statistically significant differences with other devices and produced the greater value in mean absolute errors (all P < 0.05). Conclusion: Keratometric values with standard devices are a good choice for cataract surgery, whereas the corneal topography is not an appropriate method for the assessment of preoperative keratometric values.     

Laser in situ keratomileusis using the Nidek EC-5000 or the Alcon LADARVision 4000 systems

PURPOSE: To compare the refractive results of eyes with low to moderate myopia that underwent laser in situ keratomileusis with either the Nidek EC-5000 or the Alcon LADARVision 4000 excimer laser systems. METHODS: We performed a retrospective review of 114 LASIK procedures with either the Nidek EC-5000 (54 eyes) or the Alcon LADARVision 4000 (60 eyes) excimer laser systems. Preoperative refractive errors were similar and both populations were treated during the same time period. Data analyzed included uncorrected visual acuity (UCVA), spherical magnitude, spherical equivalent refraction, astigmatism power, astigmatism axis, and vector astigmatism change. RESULTS: Results at 6 months were analyzed. Spherical correction change was a mean -3.95 D for Nidek treated eyes and a mean -4.53 D for LADARVision treated eyes (P = .20). Mean spherical equivalent refraction change was -3.70 D for Nidek eyes and -4.20 D for LADARVision eyes (P = .23). Mean change in UCVA (LogMAR) was 1.05 for Nidek eyes and 0.99 for LADARVision eyes (P = .40). Mean astigmatism magnitude change was 0.71 D for Nidek eyes and 0.77 D for LADARVision eyes (P = .63). Mean vector-corrected astigmatism change was 0.93 D for Nidek eyes and 1.00 D for LADARVision eyes (P = .63). Mean vector-corrected astigmatism axis for Nidek eyes was 3.08 D and for LADARVision eyes 6.58 D (P = .70). CONCLUSION: There was no significant difference in refractive results in eyes treated with the Alcon LADARVision 4000 or the Nidek EC-5000 excimer laser systems. Inherent differences between the two laser systems are highlighted.     

Comparing the corneal curvatures obtained from three different keratometers-IOL Master, Bausch & Lomb Manual keratometer and TOPCON KR 8800 autokeratometer

AIM: To compare the corneal curvature and to investigate the agreement between three different keratometers. METHODS: In this prospective study, keratometry was performed using an IOL Master, a Bausch & Lomb manual keratometer and TOPCON KR-8800 autokeratometer on 252 eyes of patients recruited from camps for cataract surgery. The average keratometry values were recorded and compared. The agreements between the instruments were analyzed using the Bland Altman statistical method. The main outcome measure was average keratometry values. RESULTS: The mean corneal power was 44.62±1.52 D with the IOL Master, 44.60±1.52 D with the manual keratometer, and 44.46±1.53 D with the autokeratometer. The paired ttest demonstrated a statistically significant difference in the mean corneal power between the IOL Master and manual keratometer (P=0.001), IOL Master and autokeratometer (P<0.0001), autokeratometer and manual keratometer (P<0.0001). The 95% limits of agreement (LoA) of the IOL Master and manual keratometer were -0.22 to 0.26; IOL Master and autokeratometer were -0.24 to 0.55; autokeratometer and manual keratometer were -0.30 to 0.57 as shown in the Bland-Altman plot. CONCLUSION: Keratometry data obtained with different instruments may not be interchangeable, a fact that has important implications for cataract surgeons with respect to both surgical planning and outcomes auditing.     

Toric intraocular lens for correction of high corneal astigmatism in cataract patients

AIM: To evaluate the efficacy of Bi-Flex toric intraocular lens (T-IOL; Medicontur, Medical Engineering, Ltd., Inc.) implantation to correct preexisting astigmatism in patients having cataract surgery. METHODS: This retrospective consecutive study included 22 eyes of 16 patients with more than 2.50 diopters (D) of corneal preexisting astigmatism having cataract. Preoperative and postoperative uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), objective and subjective refraction and keratometric and topographic cylinder were measured. Postoperative the toric IOL axis was evaluated using vector analysis. RESULTS: Postoperatively, subjective refractive cylinder was reduced significant (P<0.05) from 4.05±1.53 D to 1.35±0.86 D. The component J0 reduced in magnitude from -0.81±2.02 D to -0.12±0.62 D (P<0.05). Both, UCVA and BCVA improved significantly at 1mo after surgery (P<0.05 in both cases). After the surgery, the UCVA and BCVA were 0.24±0.19 and 0.06±0.08, respectively. The mean toric IOL axis rotation was 2.95±5.25 degree, with rotation less than 10 degrees in 86.36% of eyes. No differences in mean keratometric values obtained before and after surgery were found (P>0.05 for J0 and J45). CONCLUSION: Implantation of the Bi-Flex toric IOL is a safe and effective method to correct the preexisting regular astigmatism (greater than 2.50D).     

A comparison of autorefractor performance.

PURPOSE: To compare the agreement between subjective refraction and autorefraction using two commercially available autorefractors. METHODS: Prospective data were collected for 190 subjects using either the Nidek ARK-700A (Fremont, CA) or the Topcon KR-8000 (Paramus, NJ) and subjective refraction (masked to autorefraction). Refractions were compared in terms of spherical equivalent using Bland-Altman limits of agreement and astigmatic vector difference using median and 95th percentile. RESULTS: The two groups were similar for age, gender, spherical equivalent, and astigmatic power. The differences in spherical equivalent between subjective and autorefraction were significantly different (mean +/- SD; Nidek, -0.03 +/- 0.36 D; Topcon, +0.11 +/- 0.34 D; analysis of variance, F = 7.84; p < 0.01). However, the 95% limits of agreement were similar: Nidek, -0.74 to +0.68 D; Topcon, -0.55 to +0.77 D. The median differences in astigmatic vector difference were also similar: Nidek, 0.27 D and Topcon, 0.25 D. However, the 95th percentile was 0.67 D for Nidek and 1.09 D for Topcon. There was a low frequency of large (>1.00 D) differences in spherical equivalent, 1.1% with each autorefractor. There were five cases with astigmatic vector difference >1 D, all with the Topcon KR-8000 (5.3%). CONCLUSIONS: Both autorefractors show excellent agreement with subjective refraction. Despite a statistically significant difference in mean spherical equivalent (0.14 D), near identical limits of agreement (0.10 D difference) suggest clinical equivalence. Conversely, for astigmatism, despite similar median scores, major outliers were more likely with the Topcon, reflected in a 0.42 D larger 95th percentile, which suggests a small advantage for the Nidek for avoiding large astigmatic errors.     

Pseudophakic residual astigmatism

We investigated pseudophakic residual astigmatism in order to minimize postoperative refractive astigmatism. We examined 110 eyes of 87 patients who had undergone phacoemulsification with small incision and posterior chamber intraocular lens (IOL) implantation. Corneal astigmatism was measured using an autokeratometer (RK-5, canon), refractive astigmatism by manifest refraction, and residual astigmatism by vector analysis. Mean pseudophakic residual astigmatism was +0.47 x 176 degrees, predominantly against-the-rule. Variations of pseudophakic residual astigmatism according to sex, age and IOL type were not statistically significant. When performing cataract surgery as refractive surgery, we may consider that pseudophakic residual astigmatism is approximately 0.50D against-the-rule.     

Long-term existing corneal astigmatism following posterior chamber intraocular lens implantation]

Seventy-four eyes underwent extracapsular cataract extraction with posterior chamber intraocular lens implantation for two years were followed up. The examination by keratometer and manifest refraction revealed 85.14% of the eyes (63 eyes) existing > or = 0.5Diopter (D) corneal astigmatism with average 1.78 +/- 1.41 D, predominantly with-the-rule (77.03%). The results demonstrated that corneal astigmatism induced by 10-0 monofilament nylon suture was not absent completely even 2 years later postoperatively, persistent corneal astigmatism could affect ultimate uncorrected visual acuity and spectacle cylinder was almost equal to the corneal astigmatism. It was suggested that some proper measures to control corneal astigmatism following posterior chamber intraocular lens implantation must be considered.     

Objective autorefraction in posterior chamber pseudophakia.

Automated refraction with the Canon RK-1 Autoref keratometer was evaluated in 110 eyes (110 patients) six to eight weeks after they had undergone extracapsular cataract extraction with posterior chamber intraocular lens implantation and achieved a best corrected visual acuity of at least 6/12. Autorefraction readings were obtained in 100 (91%) of these eyes. The agreement between autorefraction and clinical refraction data was 98% for spherical equivalence less than 0.51 dioptres (D), 95% for sphere power less than 0.51D, 94% for cylinder power less than 0.51D, and 85% for cylinder axis less than 11 degrees. Autorefraction can provide acceptably accurate postoperative refraction values in pseudophakic eyes.     

Refractive change after vitrectomy for epiretinal membrane in pseudophakic eyes

Purpose: To report the change in refraction in pseudophakic eyes following 23‐gauge vitrectomy for epiretinal membrane (ERM), without use of silicone oil, intraocular gas or scleral buckling. Methods: Retrospective review of the records of 28 pseudophakic eyes in 28 patients undergoing 23‐gauge pars plana vitrectomy for ERM. All 28 eyes had a measured preoperative refraction in their records and were seen minimum 2 months after vitrectomy for measuring their refraction. Fellow eyes (28 eyes) were used as controls. Results: The mean preoperative refraction was ?0.15 ± 0.85 dioptre (D), and the mean postoperative refraction was ?0.41 ± 0.93 D. Thus, a myopic shift was observed following vitrectomy with a mean change in refraction of ?0.26 ± 0.60 D (range +0.75 to ?2.13 D, p = 0.032). The postoperative change in refraction was within ±0.25, ±0.50 and ±1.00 D in 39%, 68% and 96% of the eyes, respectively. The mean absolute refractive error was 0.47 ± 0.44 D. The change in refraction in fellow eyes was +0.01 D (p = 0.82). Conclusion: The change in refraction following 23‐gauge pars plana vitrectomy for ERM in pseudophakic eyes was ?0.26 D.     

Toric人工晶状体在合并高度角膜散光白内障中的应用

目的：评估Bi-Flex toric人工晶状体在合并散光的白内障中的应用。

方法：回顾性研究包括16例22眼合并2.50D以上散光的白内障患者。测量了术前与术后的裸眼视力、最佳矫正视力、客观及主观验光、角膜散光仪和角膜地形图测量的散光值。术后人工晶状体屈光轴位置使用向量进行分析。

结果：术后,主观验光散光值从4.05D±1.53D显著降低至1.35D±0.86D,(P<0.05)。屈光轴位置指标J₀,从术前的-0.81±2.02D降至 -0.12±0.62D(P<0.05)。裸眼视力和最佳矫正视力术后1mo时均显著改善(P<0.05),分别为0.24±0.19和0.06±0.08。人工晶状体屈光轴旋转程度平均为2.95±5.25度,86.36%的患眼旋转程度小于10度。术前、术后角膜散光计测量值未见显著差异(J₀ 和J₄₅均有P>0.05)。

结论：对于合并大于2.50D散光的白内障患者,Bi-Flex toric人工晶状体植入是安全有效的治疗方法。     

Comparison of objective and subjective refraction before and after laser in situ keratomileusis.

PURPOSE: To compare the accuracy and reliability of objective and subjective refractions before and after laser in situ keratomileusis (LASIK) for myopia, hyperopia, and astigmatism. SETTING: Augenchirurgie und Laserzentrum Hochrum, Innsbruck, Austria. METHODS: In this prospective study, the objective refraction obtained with the Nidek AR-K 900 autorefractor was compared with the subjective refraction in 159 eyes (125 with myopia and 34 with hyperopia) operated on with 2 different lasers. Refractions were done before and 6 months after LASIK. RESULTS: Preoperatively, the objective and subjective refractions correlated better in eyes with low myopia than in those with high myopia (P < .01). Postoperatively, objective refraction was less accurate and reliable than preoperatively. The difference between the objective and subjective spherical refractions was statistically significant (P < .0001) after LASIK in eyes with hyperopia. The correlation between the objective and subjective cylindrical refractions was stronger preoperatively. Especially after LASIK for hyperopia, the objective refraction did not reliably assess the magnitude and axis of the cylinder. The preoperative refractive error did not significantly affect the preoperative and postoperative difference between the objective and subjective refractions or the change between the preoperative and postoperative mean differences. The type of excimer laser used significantly affected the difference between the objective and subjective refractions. CONCLUSIONS: Especially after LASIK for hyperopia, the objective refraction determined with the Nidek AR-K 900 autorefractor delivered erroneous results, which have implications for postoperative care and preoperative measurements for ocular surgery such as enhancement procedures or cataract surgery.     

Changes in astigmatism after congenital cataract surgery and intraocular lens implantation using scleral tunnel incision

PURPOSE: To evaluate the post-operative changes in astigmatism in pseudophakic eyes in children. Only eyes with astigmatism of 3.0 D or more were included in the study. METHODS: The charts of children who had undergone surgery for non-traumatic cataract, using a scleral tunnel method were retrospectively reviewed. In 11 eyes with astigmatism of 3.0 D or more, the refraction was tested and recorded at 1 week, 3 months and 5 months post-operatively. The paired t-test was used to compare between the variables. RESULTS: Mean astigmatism 1 week post-operatively was 5.8 +/- 3.6 D (range 3.0-14.0 D). Thereafter, the astigmatic component of the refractive error underwent a spontaneous steady decline, reaching a mean value of 2.1 +/- 1.3 D (range 1-4.0 D) 5 months after surgery. The change in the difference between the mean values at 1 week and at 5 months was statistically significant (P < 0.005). CONCLUSION: Children who underwent congenital cataract surgery and intraocular lens implantation showed a significant spontaneous reduction in astigmatism post-operatively.     

Laser in situ keratomileusis for correction of induced astigmatism from cataract surgery

PURPOSE: To evaluate the efficacy, predictability, stability, and safety of laser in situ keratomileusis (LASIK) to correct residual astigmatism after cataract surgery. METHODS: LASIK was performed on 20 eyes of 20 patients with refractive myopic or mixed astigmatism (3.00 to 6.00 D) at least 1 year after extracapsular cataract extraction with posterior chamber intraocular lens implantation without complication. Each eye received bitoric LASIK with the Nidek EC-5000 excimer laser and the Automated Corneal Shaper microkeratome. RESULTS: At 6 months after LASIK, mean refractive cylinder decreased from 4.64+/-0.63 D to 0.44+/-0.24 D (P<.001). Mean percent reduction of astigmatism was 90.4+/-5.0% (range 80% to 100%). Mean spherical equivalent refraction decreased from -2.19+/-0.88 D (range -1.00 to -3.88 D) to -0.32+/-0.34 D (range -1.25 to +0.38 D) (P<.001). Vector analysis showed that the mean amount of axis deviation was 0.7+/-1.2 degrees (range 0 degrees to 4.3 degrees) and the mean percent correction of preoperative astigmatism was 92.1+/-5.9% (range 85.6% to 108%). Eighty-five percent of all eyes had a mean spherical equivalent refraction and mean cylinder within +/-0.50 D of emmetropia. Change in spherical equivalent refraction and cylinder from 2 weeks to 6 months was < or = 0.50 D in 90% (18 eyes) and 95% (19 eyes), respectively. Spectacle-corrected visual acuity was not reduced in any eye. Diffuse lamellar keratitis occurred in three eyes (15%) after LASIK, and were treated successfully with eyedrops. CONCLUSION: LASIK was an effective, predictable, stable, and safe procedure for correction of residual myopic or mixed astigmatism ranging from 3.00 to 6.00 D with a low spherical component after cataract surgery.     

Comparison of visual quality in cataract patients with low astigmatism after ART2 or ReSTOR intraocular lens implantation

AIM: To compare visual quality in cataract patients with low corneal astigmatism who underwent intraocular lens (IOL) implantation, and evaluate effects of low levels of astigmatism on visual outcomes in multifocal pseudophakic eyes. METHODS: This retrospective review of clinical records comprised patients with preoperative regular corneal astigmatism of 0.75-1.0 diopters (D) with-the-rule or 0.5-0.75 D against-the-rule who had uneventful cataract surgery and AcrySof IQ ReSTOR Toric-2 IOL (ART2) or AcrySof IQ ReSTOR IOL (ReSTOR) implantation. Retrospective data collection included postoperative ART2 axis rotation, uncorrected astigmatism, uncorrected entire visual acuities, distance corrected entire visual acuities, average modulation transfer function (aMTF), Strehl ratio (SR), spectacle independence, and patient satisfaction between groups. RESULTS: Mean ART2 axis rotation was 3.12°±0.70°. No secondary surgery was required to realign IOL axis. Residual astigmatism values were -0.18±0.07 D and -0.91±0.25 D in groups ART2 and ReSTOR (P<0.05). Three months postoperatively, the mean uncorrected distant, intermediate, and near visual acuities of group A were 0.01±0.05, 0.05±0.07, 0.02±0.07 logMAR, respectively; these were better than those of group R, which were 0.08±0.06, 0.15±0.12, and 0.09±0.08 logMAR, respectively (P<0.05). aMTF, SR, and spectacle independence rates were not significantly different. All patients were satisfied with postoperative results. CONCLUSION: ART2 is more suitable than ReSTOR for cataract patients with regular corneal astigmatism 0.75-1.0 D with-the-rule or 0.5-0.75 D against-the-rule.     

Combined Special Capsular Tension Ring and Toric IOL Implantation for Management of Astigmatism and High Axial Myopia with Cataracts

Aim: This study aimed to compare the effects of toric intraocular lens (IOL) implantation with a capsular tension ring and toric IOL implantation only in patients with axial myopic astigmatism who had undergone cataract surgery. Methods: Of 34 patients with axial myopia, 16 patients who had received IOL and capsular tension ring (CTR) implantation were included in the combined group and 18 patients who received toric IOL implantation only were included in the simple group. Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA) were evaluated by measuring subjective refraction, residual astigmatism, and the toric IOL axis six months post-surgery. Results: At six months postoperatively, the UCVA for the combined and simple groups was 4.6 ± 0.1 and 4.5 ± 0.2, respectively, a statistically significant difference (t = 3.531, P<0.05). The toric IOL in all of the cases was located in the capsular sac, but there were more cases with IOL rotation (12 eyes) in the simple group than in the combined group (4 eyes). The rotation angles were 20°~30° (one eye), 10°~20° (four eyes), and <10° (seven eyes) compared with 2°~5° (four eyes). The residual astigmatism was –0.50 ± 0.25 D in the combined group, not a significant difference from the predicted residual astigmatism (–0.35 ± 0.13 D). There was a significant difference in the simple group (–1.25 ± 0.33 D) when the predicted residual astigmatism was compared (–0.37 ± 0.11 D) (t = –9.511, P < 0.01). Conclusions: In patients with axial myopic astigmatism, CTR can effectively increase the rotational stability of a toric IOL, achieving improvement in corneal astigmatism and visual acuity.     

Laser in situ keratomileusis for myopia of -1.50 to -6.00 diopters

PURPOSE: To evaluate the results of laser in situ keratomileusis (LASIK) for the correction of low and moderate myopia and astigmatism using the Nidek EC-5000 excimer laser with a modified algorithm. METHODS: Three hundred and ninety-six eyes of 257 patients with myopia ranging from -1.50 to -6.00 D and astigmatism of no more than 4.00 D were included. Manifest spherical equivalent refraction, uncorrected and spectacle-corrected visual acuity were assessed at 1 month (357 eyes, 90%), 3 months (220 eyes, 56%), and 6 months (168 eyes, 42%) after LASIK. RESULTS: Mean preoperative spherical equivalent refraction was -3.60 +/- 1.27 D and mean cylinder was -1.01 +/- 1.08 D. Mean postoperative spherical equivalent refraction was -0.12 +/- 0.31 D and mean cylinder was -0.19 +/- 0.33 D. At 6 months follow-up, 158 eyes (94%) had a mean postoperative spherical equivalent refraction within +/- 0.50 D of emmetropia; 168 eyes (100%) were within +/- 1.00 D. Uncorrected visual acuity was 20/20 or better in 81% (136 eyes) and 20/40 or better in 100%. Two eyes (1.2%) lost 1 line of spectacle-corrected visual acuity due to a decentered ablation. No eye lost 2 or more lines of spectacle-corrected visual acuity. CONCLUSION: Our modified LASIK algorithm with the Nidek EC-5000 excimer laser resulted in safe and predictable outcomes for treatment of low and moderate amounts of myopia and astigmatism.     

Photoastigmatic refractive keratectomy in myopes. Nidek US Investigators Group

PURPOSE: Photoastigmatic refractive keratectomy (PARK) was studied in a multi-center clinical trial. The Nidek EC-5000 excimer laser was evaluated for its effect on refraction, visual acuity, and safety measures as part of a U.S. Food and Drug Administration (FDA) regulated study. METHODS: Eight U.S. centers enrolled adults with eyes having refractive astigmatism up to 4.00 D and a myopic spherical equivalent refraction up to -8.00 D. Results are reported for 749 eyes of 486 patients with at least 6 months follow-up. The rectangular beam scanning Nidek EC-5000 used a 5.5-mm-diameter treatment zone, a 7.0-mm-diameter peripheral blend zone, and a 40 Hz pulse rate for surface treatment of myopic astigmatism. Nomogram corrections to machine settings were required to achieve the desired results. RESULTS: Preoperative average spherical equivalent refraction of -4.90+/-1.74 D was reduced to -0.02+/-0.79 D at 6 months. Refractive stability was established at 3 months. Over 62% of eyes were within +/-0.50 D of desired correction at 6 months, with over 86% within +/-1.00 D. Uncorrected visual acuity improved by an average of 10 Snellen lines; over 64% of eyes saw 20/20 or better uncorrected and over 93% saw 20/40 or better uncorrected at 6 and 12 months. PARK treatment effectively reduced astigmatism with little average axis error or magnitude error. Corneal haze and safety concerns were minimal. CONCLUSIONS: Photoastigmatic refractive keratectomy using the Nidek EC-5000 excimer laser provided significant reduction of myopia and astigmatism, with minimal complications.     

Clinical evaluation of the Allergan Humphrey 500 autorefractor and the Nidek AR-1000 autorefractor.

AIMS/BACKGROUND: The intentions of this study were to estimate agreement between two different autorefractors and standard subjective refraction techniques and to evaluate the clinical implications of relying on the autorefractor measurements. METHODS: Subjective refraction was carried out on 448 cycloplegic eyes and compared with cycloplegic readings with the Allergan Humphrey 500 autorefractor (448 eyes) and the Nidek AR-1000 autorefractor (160 eyes). Each refraction was followed by clinical visual acuity measurement. The study population comprised 224 healthy students, 107 men and 117 women, with a mean age of 20.6 (SD 1.1) years. RESULTS: Both the Nidek and Humphrey autorefractors measured more negative or less positive refractive values compared with subjective refraction and these biases were statistically significant (Humphrey right eye -0.23 D, p = 0.0001, left eye -0.20 D, p = 0.0001), (Nidek right eye -0.13 D, p = 0.0001, left eye -0.11 D, p = 0.0002). Comparing the results of autorefraction with subjective refraction, the Nidek was better than the Humphrey autorefractor in several ways: a smaller mean difference, better agreement between spherical equivalent values, narrower limits of agreements, and better visual acuity obtained with the autorefraction. On the other hand, the Humphrey autorefractor agreed better with subjective refraction concerning cylinder axis. CONCLUSION: The results show that both autorefractors represent a valuable complement to subjective refraction, but cannot be used as a replacement.     

Laser in situ keratomileusis for hyperopia and hyperopic astigmatism with the Nidek EC-5000 Excimer laser.

PURPOSE: We evaluated the efficacy, predictability, stability, and safety of laser in situ keratomileusis (LASIK) for hyperopia and hyperopic astigmatism. METHODS: A retrospective study was performed for 92 eyes of 62 consecutive patients to evaluate uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA) and manifest refraction before and 3 and 6 months after LASIK (Moria LSK-ONE microkeratome, Nidek EC-5000 excimer laser). Eyes were divided into groups: Group 1 (low hyperopia) for spherical correction of +1.00 to +3.00 D (22 eyes), Group 2 (low hyperopic astigmatism) for toric correction with spherical equivalent refraction of +1.00 to +3.00 D (18 eyes), Group 3 (moderate hyperopia) for spherical correction of +3.25 to +6.00 D (10 eyes), and Group 4 (moderate hyperopic astigmatism) for toric correction with spherical equivalent refraction between +3.25 and +6.00 D (18 eyes). RESULTS: At 3 and 6 months after LASIK, 68 eyes (73.9%) were available for follow-up examination. Percentage of eyes with a spherical equivalent refraction within +/-0.50 D of emmetropia for Group 1 was 54.5% (12 eyes); Group 2, 50% (9 eyes); Group 3, 40% (4 eyes), and Group 4, 38.8% (7 eyes). UCVA > or =20/20 in Group 1 was 14% and in Groups 2, 3, and 4, 0%. One eye (5.5%) lost two lines of BSCVA. CONCLUSION: LASIK with the Moria LSK-ONE microkeratome and the Nidek EC-5000 excimer laser reduced low and moderate hyperopia and was within +/-0.50 D of target outcome in approximately 50% of eyes. Undercorrection was evident in all groups. The procedure was safe.