Quinn Graham E, Francis Ellie L, Nipper Karen S, Flitcroft D Ian, Ying Gui-shuang, Rees Renee C, Schmid Gregor F, Maguire Maureen G, Stone Richard A
Division of Pediatric Ophthalmology, The Children's Hospital of Philadelphia, One Children's Center, PA 19104, USA.
Arch Ophthalmol. 2003 Jul;121(7):985-90. doi: 10.1001/archopht.121.7.985.
To determine the feasibility, reliability, and validity of using partial coherence interferometry, a noncontact method that detects interference patterns from various layers of the eye, to measure axial length in young children.
The right eye of 64 subjects (mean age, 8.4 y; age range, 3.4-12.9 y; best-corrected visual acuity >or=20/30) was measured. Subjects fixated monocularly on the collimated light pattern from a laser diode (the alignment beam) and the operator used a video monitor to align the corneal reflection in the optical path. Axial length was measured during an 0.8-second scan using interference patterns from a collimated short coherence superluminescence diode aligned coaxially with the laser diode. Five series of 16 readings each were obtained. The average axial length for each of the 5 series of readings was calculated. Main Outcome Measure Axial length.
Within-subject precision of axial length measurements was high, with an overall SE of measurement of 8 micro m for individual subjects across the 5 sessions (95% confidence interval, +/-16 micro m). Subgroup analysis showed that sex, age, spherical equivalent, and refractive error exerted statistically significant effects on precision, but all of the differences among subgroups were 3 micro m or less and likely to be insignificant clinically. Axial length measured by partial coherence interferometry varied systematically, with factors known to influence eye length (ie, age and refractive error), further validating the measurement method.
The partial coherence interferometry technique provides reproducible, extraordinarily precise eye length measurements in young children and should enable novel approaches to study eye growth and refractive development.
确定使用部分相干干涉测量法（一种检测来自眼睛各层干涉图样的非接触方法）测量幼儿眼轴长度的可行性、可靠性和有效性。
对64名受试者（平均年龄8.4岁；年龄范围3.4 - 12.9岁；最佳矫正视力≥20/30）的右眼进行测量。受试者单眼注视来自激光二极管的准直光图案（校准光束），操作人员使用视频监视器在光路中校准角膜反射。在0.8秒的扫描过程中，使用与激光二极管同轴对准的准直短相干超发光二极管产生的干涉图样测量眼轴长度。共获得5组，每组16次读数。计算5组读数中每组的平均眼轴长度。主要观察指标为眼轴长度。
眼轴长度测量的受试者内精度较高，在5次测量中，个体受试者的总体测量标准误为8μm（95%置信区间，±16μm）。亚组分析表明，性别、年龄、等效球镜度和屈光不正对精度有统计学显著影响，但亚组间的所有差异均为3μm或更小，临床意义可能不大。通过部分相干干涉测量法测得的眼轴长度随已知影响眼轴长度的因素（即年龄和屈光不正）而系统变化，进一步验证了测量方法。
部分相干干涉测量技术可在幼儿中提供可重复、极其精确的眼轴长度测量结果，应为研究眼球生长和屈光发育提供新方法。
