Untersuchung von Kindergartenkindern auf Refraktionsanomalien

BACKGROUND: Since ametropia is a leading cause of amblyopia refractive screening of preschool children is recommended. Measurement of refraction using tabletop autorefractors can be difficult or impossible due to lack of cooperation in this age group. The intention of the present study is to evaluate the use of a new handheld autorefractor for screening in kindergartens. METHODS: A total of 216 children aged 3.5-4.5 years were examined without cycloplegia using the handheld autorefractor (SureSight, Welch Allyn) in their kindergartens. RESULTS: Using the test device the majority of the examined eyes showed mild hyperopia (on average +1.18+/-0.87 dpt spherical equivalent) and mild astigmatism (on average 0.60+/-0.46 dpt cylinder power). The reproducibility of repeated autorefractor readings was higher for cylinder power and axis than for the spherical equivalent. Autorefractor readings of 55 eyes could be compared with the results of cycloplegic retinoscopy. The results were similar between the two measurements with differences of no more than 0.5 dpt in 18.2% for the spherical equivalent, in 82.1% for cylinder power, and in 66.6% for axis (weighted axis difference). There was adequate cooperation in 99.5% of the children. CONCLUSION: The handheld autorefractor proved an accuracy of measurement comparable to that of conventional tabletop autorefractors for cylinder power and axis with limitations in accuracy for the spherical equivalent. Validity and threshold values for relevant abnormalities are to be evaluated in further studies. By the high cooperation rate the instrument proved useful for screening examinations in preschool children.     

Validation of aberrometry-based relative peripheral refraction measurements.

PURPOSE: To validate aberrometry-based relative peripheral refraction (RPR) measurements and to examine RPR differences in the nasal and temporal horizontal visual field. METHODS: Thirty subjects underwent cycloplegia in the right eye. Ten measurements each were made centrally, 30 degrees nasally on the retina and 30 degrees temporally on the retina using the Complete Ophthalmic Analysis System (COAS) aberrometer and the Grand Seiko WR-5100K autorefractor in random order. A 2-mm COAS analysis diameter was used to approximate the Grand Seiko autorefractor measurement beam diameter. Nasal and temporal RPR were calculated as the difference between the average nasal or temporal spherical equivalent and the average central spherical equivalent. Repeated measures ANOVAs were used to test for significant differences between the RPR readings of each instrument in each retinal location (nasal or temporal) and to examine refractive error in each direction of gaze for both instruments. RESULTS: Central spherical equivalent refractive error as measured by the Grand Seiko autorefractor ranged from +0.63 D to -8.41 D (mean +/- S.D. = -2.63 D +/- 2.05 D). There were no significant differences between the instruments for RPR measurements (p = 0.34). The nasal RPR was significantly more hyperopic than the temporal RPR (mean +/- S.D. = +0.45 D +/- 1.04 D, p = 0.02). Spherical equivalent refractive error in all directions of gaze was more myopic with the COAS than with the Grand Seiko autorefractor (mean +/- S.D. = -0.41 D +/- 0.61 D, p < 0.0001). CONCLUSIONS: RPR measurements with the COAS are feasible and equivalent to those made with the Grand Seiko autorefractor. The COAS can be used to simultaneously collect RPR and peripheral aberration data. Nasal and temporal RPR measurements were significantly different in our sample.     

Multiple regression and vector analyses of laser in situ keratomileusis for myopia and astigmatism.

PURPOSE: To construct a quantitative model relating refractive results to laser settings and other factors. METHODS: A prospective clinical trial was performed, including 14 surgeons and 523 eyes of 278 patients who desired correction of myopia from -1.00 to -16.00 D (mean, -6.20 D) and astigmatism up to 6.00 D (mean, 1.10 D). Myopia and astigmatism were corrected by laser in situ keratomileusis (LASIK) with sequential spherical and cylindrical ablations using a 5.5-mm ablation zone and a transition zone to 7.0 mm. The Nidek EC-5000 excimer laser and the Chiron Automated Corneal Shaper were used. RESULTS: Surgically induced refractive changes 3 months after surgery were measured. Spherical ablation by LASIK produced a 19% greater refractive change than that predicted by the Nidek PRK algorithm. The laser setting needed to achieve each 1.00 D of cylinder correction induced 1.30 D change in spherical equivalent refraction (0.80 D more than expected). Patient age and nonlinear effects had small but statistically significant influences on refractive outcome. Sex, left/right eye, and surgeon were not significant factors. Residual variations in spherical equivalent refraction included a 0.50-D constant plus 9% of the predicted spherical equivlanet change. Residual variations in the parallel and orthogonal components of cylinder correction were, respectively, 28% and 13% of the predicted cylinder change plus a 0.30-D constant component. The standard deviation of axis alignment error for cylinder ablation was 3.7 degrees. CONCLUSIONS: Cylindrical ablation produced a spherical change that was larger than expected. To compensate for this, spherical ablation should be reduced in eyes with astigmatism. Variability in the correction of astigmatism was proportionally larger than that for spherical correction and was primarily due to magnitude rather than axis error.     

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 correction of high astigmatism after penetrating keratoplasty

PURPOSE: To evaluate the safety and efficacy of laser in situ keratomileusis (LASIK) for correction of high astigmatism after penetrating keratoplasty, and to assess the refractive results and predictability of the procedure. METHODS: LASIK was performed on 19 patients (19 eyes) with high astigmatism after penetrating keratoplasty, using the Chiron Automated Corneal Shaper and the Chiron-Technolas Keracor 116 excimer laser. The amount of preoperative refractive astigmatism ranged from 6.50 to 14.50 D (mean, 9.21 +/- 1.95 D) and the spherical component of manifest refraction ranged from -7.00 to +1.25 D (mean, -2.14 +/- 2.11 D). All patients completed a minimum follow-up of 12 months. RESULTS: Refraction was stable after 3 months. At 1 year after LASIK, the amount of refractive astigmatism was reduced to a mean of 1.09 +/- 0.33 D (range, 0.50 to 1.75 D), with 57.9% of the eyes within +/- 1.00 D of refractive astigmatism. The mean percent reduction of astigmatism was 87.9 +/- 3.7%. The postoperative spherical component of manifest refraction ranged from -1.00 to +1.75 D with a mean of +0.43 +/- 0.82 D. Vector analysis showed that the mean amount of axis deviation was 1.1 +/- 1.3 degrees and the mean percent correction of preoperative astigmatism was 92.6 +/- 8.4%. There were no intraoperative complications. Spectacle-corrected visual acuity was not reduced in any eye, and improved by 2 or more lines in 42.1% of eyes after LASIK. CONCLUSION: LASIK with the Chiron-Technolas Keracor 116 excimer laser was effective for correction of both astigmatism and myopia after penetrating keratoplasty. The procedure proved to be safe and gave fairly predictable and stable refractive results.     

Evaluation of a clinical aberrometer for lower-order accuracy and repeatability, higher-order repeatability, and instrument myopia.

BACKGROUND: Refractive surgery has stimulated the development of aberrometers, which are instruments that measure higher-order aberrations. The purpose of this study was to test one clinical aberrometer, the Complete Ophthalmic Analysis System (COAS), for its accuracy, repeatability, and instrument myopia for measuring sphere and astigmatism and its repeatability for measuring higher-order aberrations. METHODS: Aberrations of 56 normal eyes (28 subjects) were measured with and without cycloplegia using a COAS, a conventional autorefractor and by subjective refraction. We evaluated lower-order accuracy (sphere and astigmatism) of the COAS and autorefractor by comparing that data with that of subjective refraction. We also tested COAS lower- and higher-order repeatability for 5 measurements taken in less than 1 minute. We evaluated instrument myopia by comparing cycloplegic and noncycloplegic measurements of the same eye. Data were analyzed for a 5.0-mm-diameter pupil. RESULTS: Mean COAS spherical error was between -0.1 and +0.4 diopters (D), depending on cycloplegia and the kind of sphere power computation selected. Cylinder power errors were less than 0.1 D. COAS repeatability coefficients were better than 0.25 D, and instrument myopia was less than 0.4 D. These were comparable with those of autorefraction. Higher-order repeatability was sufficient to allow reliable measurement of normal third-order aberrations and spherical aberration. CONCLUSIONS: Accuracy, repeatability, and instrument myopia of the COAS are similar to those of a conventional autorefractor. Accuracy and repeatability are also similar to those of subjective refraction. Like an autorefractor, the COAS provides instantaneous, objective measurements of sphere and astigmatism, but it also measures higher-order aberrations. We found that it is capable of reliably measuring problematic higher-order aberrations and is therefore a valuable asset for modern clinical eye care.     

Validity of autorefraction after cataract surgery with multifocal ReZoom intraocular lens implantation

PURPOSE: To evaluate the clinical utility of spherocylindrical automated refraction (AR) compared with subjective manifest refraction (MR) after cataract surgery with implantation of ReZoom refractive multifocal intraocular lenses (IOLs) (Advanced Medical Optics, Inc.). SETTING: Private Practice. METHODS: This prospective nonrandomized interventional study consisted of 72 patients with bilateral cataract and a potential visual acuity of at least 20/40. Patients had bilateral nonsimultaneous cataract surgery and implantation of a ReZoom IOL. Manifest refraction was performed in all patients followed by 3 consecutive measurements using the Topcon KR-8000 autorefractor with nondilated and dilated pupils. Assessment of repeatability of multiple consecutive ARs and comparison of the AR and MR using power vector analysis were performed at the 6-month follow-up. The main outcome measures were the correlation between AR and MR with sphere, spherical equivalent, and astigmatism as well as the repeatability of AR before and after dilation with phenylephrine 10%. RESULTS: Repeatability analysis showed that the initial nondilated AR was not significantly different from the mean of the 3 refractions for nondilated and dilated measurements. The mean difference between the initial AR and the MR was -0.84 +/- 0.62 diopters (D) for sphere (SD), -1.00 +/- 0.61 D for spherical equivalent, and -0.06 +/- 0.19 D and -0.01 +/- 0.17 D, respectively, for J(0) and J(45), the 2 components of astigmatism. Linear regression of AR versus MR data showed poor correlation for sphere (R(2) = 0.4852) and spherical equivalent (R(2) = 0.5529), whereas the correlation for the 2 astigmatic components of vector analysis was excellent (J(0), R(2) = 0.8881; J(45), R(2) = 0.8640). Correlation was better when the MR residual refractive defect was higher. CONCLUSIONS: Although autorefraction showed excellent agreement with subjective refractive astigmatism, correlation with spherical values was poor, with a trend toward more negative values. Autorefraction after ReZoom IOL implantation can be used as a good starting point for subjective refraction of astigmatism; however, spherical values should be underestimated.     

Comparisons of the handheld autorefractor, table-mounted autorefractor, and subjective refraction in Singapore adults.

PURPOSE: The purpose of this article was to compare the Retinomax with the table-mounted autorefractor and subjective refraction in Singapore adults. METHODS: Adults (n = 100) attending a tertiary eye hospital clinic were examined by an optometrist. First, subjective refraction testing was performed using a trial lens set, followed by handheld autorefractor tests using the Nikon Retinomax and the table-mounted autorefractor (Topcon RM8000B). Spherical equivalent and vector components of astigmatism were analyzed: J0 (Cartesian astigmatism) and J45 (oblique astigmatism). RESULTS: The Retinomax autorefractor readings (mean = -4.69 D) were more minus compared with the table-mounted autorefractor (mean = -4.05 D) and subjective refraction (mean = -3.90 D). There were significant differences in J0 and J45 for comparisons between subjective refraction and Retinomax autorefraction, and table-mounted autorefraction and Retinomax autorefraction. CONCLUSION: The Retinomax autorefractor measures were more minus compared with the table-mounted autorefractor and subjective refraction. The Retinomax autorefractor is not recommended for research purposes, unless in remote inaccessible areas where a portable instrument is necessary and cycloplegia is not possible.     

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.     

The association of astigmatism and spherical refractive error in a high myopia cohort.

PURPOSE: The purposes of this study were to determine whether the degree of myopia influences the presence and degree of total astigmatism, and to assess risk factors of astigmatism in patients with familial nonsyndromic severe myopia. METHODS: We performed a retrospective study of 217 subjects from families with two or more subjects from successive generations with a myopic spherical refractive error of at least -5 D or greater in one eye. Mean myopic spherical equivalent was -10 D and the mean age of myopia onset was 7 years. Refractive error measurements were obtained and the association between the degree of myopia and cylinder power was examined by correlation analysis. RESULTS: The prevalence of astigmatism (1.0 D of cylinder) was 36.1%. With-the-rule astigmatism was most common (55.8%), and the majority of astigmats had between 1.0 and 2.5 D of cylinder (77.6%). Statistically significant associations were found between the presence of astigmatism and risk factors of age and the age of myopia onset. In those patients with astigmatism, however, there was a moderate correlation between the degree of spherical equivalent and cylinder power (r = -0.34, p < 0.0001). Younger age (<16 years) (p = 0.03) was associated with higher cylinder power. CONCLUSIONS: In severely myopic patients, there is a high prevalence of astigmatism that is predominantly with-the-rule. The degree of myopic spherical refractive error is correlated with astigmatism severity but is not a risk factor for the presence of astigmatism.     

Standardized arcuate keratotomy for postkeratoplasty astigmatism

PURPOSE: To assess the effect of standardized, paired arcuate keratotomy (AK) on the change in astigmatism in postkeratoplasty eyes. SETTING: Moorfields Eye Hospital, London, United Kingdom. METHODS: A retrospective review was conducted of 20 eyes of 19 patients having the same AK procedure regardless of the magnitude of the preoperative astigmatism. Each eye had a pair of 60-degree arc length incisions placed in the corneal stroma. The incisions were 600 mum deep and 6.0 mm apart. The preoperative and postoperative refractions and complications were analyzed. Astigmatic change was analyzed without regard to axis, as surgically induced refractive change, and using a modified polar plot of change in astigmatism. RESULTS: The mean cylinder was reduced from -10.99 diopters (D) +/- 4.26 (SD) to -3.33 +/- 2.18 D. There was no significant change in the mean spherical equivalent. There was a strong correlation between the magnitude of the preoperative cylinder and the magnitude of the change in astigmatism (R2 = 0.76). In 3 eyes, the surgically induced axis of astigmatism was more than 15 degrees from that expected. CONCLUSIONS: In postkeratoplasty eyes, the change in the magnitude of astigmatism induced by standardized AK was proportional to the preoperative magnitude of astigmatism. Arcuate nomograms for congenital astigmatism have no role in the management of astigmatism in postkeratoplasty eyes.     

新生儿期不同月龄屈光发育的特征及间接接触蓝光照射对屈光发育影响的临床研究

目的探讨新生儿期不同月龄屈光发育的特征及间接接触蓝光照射对屈光发育的影响。 方法选择2016年1月至2020年6月于北京大学第三医院儿科因新生儿高胆红素血症曾行蓝光照射治疗的患儿82例(164只眼)和出生时健康的婴幼儿64例(128只眼)作为研究对象。其中,男性86例(172只眼),女性60例(120只眼);年龄6~36个月,平均年龄(31.1±6.7)个月。根据是否在新生儿期接受过蓝光治疗,分为光疗组和对照组。检查并记录所有患儿出生后6个月、12个月、18个月及24个月在非睫状肌麻痹状态下双眼的等效球镜度、球镜度、散光度及散光轴位。年龄以±s表示,组间的比较采用t检验;性别为计数资料,以例数和百分比表示,组间的比较采用卡方检验。所有患儿各时间段内的等效球镜度、球镜度、散光度及散光轴位经正态性检验为偏态分布,屈光状态各参数均采用中位数和四分位距表示,组间比较采用Mann-Whitney U秩和检验。月龄与组别对屈光状态各值的影响采用混合效应模型分析。 结果光疗组患儿80例(80只眼),对照组患儿74例(74只眼)。两组患儿月龄比较的差异无统计学意义(t＝-1.1,P>0.05);性别比较的差异无统计学意义(χ²＝0.32,P>0.05)。光疗组患儿6月龄时的等效球镜度、球镜度、散光度及散光轴位分别为0.17(1.96)D、1.0(2.0)D、-1.25(1.0)D及75.5(155.3)°;对照组分别为-0.13(2.63)D、0.5(2.0)D、-1.20(1.0)D及93.5(138.0)°。经Mann-Whitney U检验,两组比较的差异均无统计学意义(Z＝-0.89,-0.939,-1.721,-0.555;P>0.05)。光疗组患儿12月龄时的等效球镜度、球镜度、散光度及散光轴位分别为0.17(1.98)D、0.51(1.88)D、-0.67(1.0)D及73.5(105.0)°;对照组分别为0.13(1.92)D、0.25(0.92)D、-0.94(1.0)D及90.0(109.0)°。经Mann-Whitney U检验,两组等效球镜度和球镜度比较的差异均有统计学意义(Z＝-2.634,-2.353;P<0.05);散光度和散光轴位比较的差异均无统计学意义(Z＝-0.144, -1.445;P>0.05)。光疗组患儿18月龄时的等效球镜度、球镜度、散光度及散光轴位分别为0.25(1.25)D、0.75(1.50)D、-0.75(0.7)D及90.0(125.0)°;对照组分别为0.13(1.92)D、0.33(2.42)D、-0.58(0.67)D及98.0(105.3)°。经Mann-Whitney U检验,两组比较的差异均无统计学意义(Z＝-0.213,-0.988,-1.404,-0.697;P>0.05)。光疗组患儿24月龄时的等效球镜度、球镜度、散光度及散光轴位分别为0.17(0.43)D、0.50(0.58)D、-0.50(0.42)D及92.5(90.5)°;对照组分别为0.15(1.33)D、0.42(1.47)D、-0.71(0.63)D及105.0(64.0)°。经Mann-Whitney U检验,两组比较的差异均无统计学意义(Z＝-0.285,-0.544,-1.322,-1.472;P>0.05)。以月龄作协变量,组别作因子,经混合效应模型分析显示,二者对等效球镜度、球镜度、散光度及散光轴位比较的差异均无统计学意义(t＝1.365,1.479,-0.668,-1.818;P>0.05)。月龄对散光度的影响有统计学意义(t＝7.609,P<0.05);对等效球镜度、球镜度及散光轴位的影响均无统计学意义(t＝0.282,-1.659,1.052;P>0.05)。 结论婴幼儿出生后由高度远视眼向正视眼逐渐发展,在婴幼儿出生后早期接受蓝光照射治疗后,短期内的屈光发育状态不会受其影响。     

PowerRefractor versus Canon R-50 Autorefraction to assess refractive error in children: a community-based study in ecuador.

PURPOSE: To compare the agreement of the PowerRefractor with Canon R-50 autorefraction for measuring refractive error in a community of Ecuadorian children. METHODS: We examined 1564 children aged 5 to 6 years from two ethnically and geographically similar regions of the Ecuadorian highlands. Results of a refraction obtained without cycloplegia with the PowerRefractor and with the Canon R-50 autorefractor (NCAR) were compared with the gold-standard examination, cycloplegic autorefraction (CAR) with the Canon R-50 autorefractor. Power vectors were used to analyze refractive error. Bland-Altman limits of agreement were obtained. RESULTS: Although the mean difference in the spherical equivalent refractive error between the PowerRefractor and CAR was small (-0.03 D +/- 0.05 D), the 95% limits of agreement were wide (+/-2.03 D). On the other hand, NCAR showed a greater bias (0.97 D +/- 0.04 D) and smaller limits of agreement (+/-1.49 D). The limits of agreement of the PowerRefractor were also wider than NCAR for measuring astigmatism. When the mean difference was stratified by the subgroups of refractive error vectors, the PowerRefractor was found to have poorer limits of agreement than NCAR for hyperopic defects. CONCLUSION: The PowerRefractor is accurate, but not as precise for measuring refractive error as compared to the Canon R-50 autorefractor, especially for high hyperopia.     

Laser in situ keratomileusis retreatment for residual myopia and astigmatism

PURPOSE: To evaluate the visual and refractive results of laser in situ keratomileusis (LASIK) retreatment on eyes with residual myopia with or without astigmatism. METHODS: LASIK retreatment was performed on 35 eyes of 23 patients for correction of residual myopia, with or without astigmatism, with a mean manifest spherical equivalent refraction of -2.17+/-0.82 D (range, -1.00 to -3.87 D) and mean refractive astigmatism of -0.55+/-0.61 D (range, 0 to -1.75 D). Retreatment was performed 3 to 18 months after primary LASIK (mean, 5.1+/-2.6 mo). The corneal flap of the previous LASIK was lifted and laser ablation was performed using the Chiron-Technolas Keracor 116 excimer laser. Follow-up was 12 months for all eyes. RESULTS: At 1 year after retreatment, manifest spherical equivalent refraction was reduced to a mean -0.23+/-0.28 D (range, 0 to -0.87 D), and refractive astigmatism was reduced to a mean -0.16+/-0.25 D (range, 0 to -0.75 D). Thirty-two eyes (91.5%) had a manifest spherical equivalent refraction within +/-0.50 D of emmetropia, and 33 eyes (94.3%) had 0 to 0.50 D of refractive astigmatism. Uncorrected visual acuity was 20/20 or better in 11 eyes (31.4%). Spectacle-corrected visual acuity was not reduced in any eye after retreatment. There were no significant complications. CONCLUSION: LASIK retreatment was effective for correction of residual myopia or astigmatism after primary LASIK. Refractive results were predictable with good stability after 3 months. Lifting the flap during LASIK retreatment was relatively easy to perform and did not result in visual morbidity in eyes treated from 3 up to 18 months after primary LASIK.     

Cycloplegic refraction in preschool children: comparisons between the hand-held autorefractor, table-mounted autorefractor and retinoscopy

Aims: It is common for refraction to be measured using different testing methods in children, with much debate still ongoing on the preferred method. Therefore, we compared cycloplegic refraction measurements using three objective methods in a large cohort of children. Methods: We present the findings from a total of 51 children who were recruited and examined as part of the Strabismus, Amblyopia and Refractive error in Singapore preschool children (STARS) study. Each child underwent a comprehensive eye examination, which included cycloplegic refraction using a hand‐held autorefractor (Retinomax), a table mounted autorefractor (Canon FK‐1) and streak retinoscopy. Spherical equivalent (SE) was calculated as (sphere + half of minus cylinder) and astigmatism was determined using the negative cylindrical component. Results: The current study sample consisted of 29 boys and 22 girls aged between 24 and 72 months (mean age 52.3 months). The mean spherical equivalent (SE) using the table‐mounted autorefractor (1.03 ± 1.64 D) was not significantly different from the streak retinoscopy (1.09 ± 1.58 D, p = 0.66). However, the mean SE using the hand‐held Retinomax (0.80 ± 1.43 D) was significantly different (more ‘minus’p = 0.0004) to streak retinoscopy. The astigmatism measured using the hand held (?0.89 ± 0.51 D) and table‐mounted autorefractor (?0.83 ± 0.61 D) were significantly greater than that obtained with streak retinoscopy (?0.58 ± 0.56, p = 0.0003). Conclusions: The table‐mounted autorefractor provided a reading more similar to that of streak retinoscopy than to that of the hand‐held autorefractor. However, there were only small differences in mean SE (<0.32 D) between the hand‐held Retinomax and the other methods, which will have implications in research investigations of refractive error.     

国产HAR-800手持验光仪在学龄前儿童弱视筛查中的作用

目的:评估HAR-800手持自动验光仪筛查弱视的价值。方法:分析上海市静安区江宁街道7所托幼机构1027名学龄前儿童屈光检查结果和弱视关系,屈光检查通过HAR-800手持自动验光仪获得。绘制受试者屈光异常和弱视间的工作曲线,计算自动验光仪筛查弱视的敏感性、特异性、准确性和一致性。结果:其中44例儿童被确诊为弱视。屈光检查筛查弱视的ROC曲线图显示屈光参差、球镜、散光三个指标的ROC曲线下面积分别为0.92,0.89,0.21。屈光参差和球镜可以用作筛查弱视的指标。当屈光参差0.88D或远视在2.5D时作为弱视筛查的标准敏感性分别为77.3%,72.7%;特异性分别99%,98.8%;准确性分别为93.4%,93.3%;Kappa均大于0.4。结论:HAR-800手持验光仪可以用于学龄前儿童弱视的筛查。     

Examination of preschool children for ametropia: first experiences using a new hand-held autorefractor

INTRODUCTION: Over the last decades, various methods have been investigated for preschool screening for amblyogenic ametropia. The SureSight is a new hand-held wavefront-analyzing autorefractor designed for screening. METHODS: A total of 338 children (3 1/2 - 4 1/2 years-old) were examined in their kindergartens without cycloplegia using the new instrument. Of these, 56 had a cycloplegic retinoscopy as a reference measurement. Hyperopia > or =3 dpt, myopia > or =1 dpt, astigmatism > or =1 dpt and anisometropia > or =1 dpt were considered amblyogenic ametropia. RESULTS: Testability was 99.4%. Accuracy was high for cylinder power and axis but poor for the spherical equivalent. Sensitivity was 41% for the detection of amblyogenic hyperopia, 95% for astigmatism and 75% for anisometropia, with specificity values of 92, 79 and 73%. CONCLUSION: The high testability and accuracy for cylinder power and axis are the strong points. The poor accuracy for the spherical equivalent is probably caused by the lack of cycloplegia. At present, non-cycloplegic autorefractor screening cannot be recommended due to the low specificity. Our findings support the advice that objective refraction in childhood must be performed with cycloplegia.     

Screening for refractive errors in children: accuracy of the hand held refractor Retinomax to screen for astigmatism

AIMS: To assess the reliability of the hand held automated refractor Retinomax in measuring astigmatism in non-cycloplegic conditions. To assess the accuracy of Retinomax in diagnosing abnormal astigmatism in non-cycloplegic refractive screening of children between 9 and 36 months. METHODS: Among 1205 children undergoing a non-cycloplegic refractive screening with Retinomax, 299 (25%) had repeated non-cycloplegic measurements, 302 (25%) were refracted under cycloplegia using the same refractor, and 88 (7%) using retinoscopy or an automated on table refractor. The reproducibility of non-cycloplegic cylinder measurement was assessed by comparing the cylindrical power and axis values in the 299 repeated measurements without cycloplegia. The influence of the quick mode on cylinder measurement was analysed by comparing the cylinder and axis value in 93 repeated measurements without cycloplegia where normal mode was used in one measurement and quick mode in the other. Predictive values of the refractive screening were calculated for three different thresholds of manifest astigmatism (> or = 1.5, > or = 1.75, and > or = 2 D) considering as a true positive case an astigmatism > or = 2 D under cycloplegic condition (measured by retinoscopy, on table, or hand held refractor). RESULTS: The 95% limits of agreement between two repeated manifest cylinder measurements with Retinomax attained levels slightly less than plus or minus 1 D. The 95% limits of agreement for the axis were plus or minus 46 degrees. The comparison of non-cycloplegic measurements in the quick and normal mode showed no significant difference and 95% limits of agreement plus or minus 0.75 D. The mean difference between non-cycloplegic and cycloplegic cylinder values measured by Retinomax reached 0.17 D and was statistically significant. Manifest thresholds of > or = 1.5 D, > or = 1.75 D, > or = 2 D cylinder value diagnosed 2 D of astigmatism under cyclplegia respectively with 71-84%, 59-80%, 51-54% of sensitivity (right eye-left eye) and 90-92%, 95%, 98% of specificity. CONCLUSION: Without cycloplegia, Retinomax is able to measure cylinder power with the same reproducibility as cycloplegic retinoscopy. No significant difference was found in the cylinder values obtained with the quick and the normal modes. Therefore, the quick mode of measurement is recommended as it is more feasible in children. No difference, which is significant from a screening point of view, exists between the non-cycloplegic and the cycloplegic cylinder value (< 0.25 D). Retinomax diagnoses abnormal astigmatism (> or = 2 D) in a non-cycloplegic refractive screening at preschool ages with 51-84% sensitivity rates and 98-90% specificity rates, depending on the chosen threshold of manifest astigmatism. If 2 D of manifest astigmatism is chosen as a positive test, the positive predictive value of the screening reaches 81-84% and the negative predictive value 91-90% (right eye-left eye).     

Laser in situ keratomileusis for myopic astigmatism

PURPOSE: To evaluate the refractive results of laser in situ keratomileusis (LASIK) for myopic astigmatic eyes, and to assess the efficacy, accuracy, stability, and safety of the procedure. METHODS: LASIK was performed on 113 eyes of 73 patients for correction of myopic astigmatism ranging from 1.00 to 5.00 D, as measured by manifest refraction, with a mean baseline refractive astigmatism of 2.09 +/- 1.12 D. The Chiron Automated Corneal Shaper was used to create a corneal flap, and laser ablation was performed using the Chiron-Technolas Keracor 116 excimer laser. Follow-up time was 12 months for all eyes. RESULTS: Refractive astigmatism was stable by 3 months after surgery. At 1 year after LASIK, refractive astigmatism was reduced to a mean of 0.25 +/- 0.31 D (range 0 to 1.00 D). Sixty-one eyes (54%) had no residual astigmatism and 98 eyes (86.7%) had 0 to 0.50 D of refractive astigmatism. The mean percent reduction of preoperative astigmatism was 87.9 +/- 14.9%. The mean axis deviation of the surgically induced astigmatism was 2.1 +/- 3.1 degrees, with 96 eyes (84.9%) within 5 degrees of the desired axis. The percent correction of preoperative astigmatism in the proper axis was 97.1 +/- 15.5%. Spectacle-corrected visual acuity improved by 2 lines in 11 eyes (9.7%), and was reduced by 1 line only in 1 eye. There were no other significant complications. CONCLUSION: LASIK with the Chiron-Technolas Keracor 116 excimer laser was effective for correction of myopic astigmatism, with good stability after 3 months. The results were predictable with an acceptable degree of accuracy. LASIK is a safe procedure with very few complications.