Schwartz-Goldstein B H, Hersh P S
Department of Ophthalmology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY 10467, USA.
Ophthalmology. 1995 Jun;102(6):951-62. doi: 10.1016/s0161-6420(95)30928-1.
To determine the amount of optical zone decentration in patients who have undergone excimer laser photorefractive keratectomy (PRK) and assess associations of both decentration and optical zone size with clinical outcomes.
Optical zone centration in 185 patients after PRK was analyzed using computer-assisted videokeratography. A comparison of decentration among the five study centers was performed. Associations of clinical outcomes with procedure decentration and optical zone size were assessed.
Decentration from the pupil center ranged from 0.00 to 1.44 mm (mean, 0.46 mm): 21.8% were decentered 0.25 mm or less, 42.5% > 0.25 mm and < or = 0.50 mm, and 97.1% < or = 1.00 mm. In both eyes, the average decentration from the pupil center was located inferonasally. Decentrations among the five study centers were significantly different. Decentration was associated with attempted refractive correction, change in keratometric cylinder, and patient satisfaction. There was a trend toward worse postoperative uncorrected visual acuity with greater decentration but no association with best-corrected vision, predictability, or refractive astigmatism. No significant relation was found between decentration and glare/halo ranking; however, three of six patients with 1.00 mm or greater of decentration demonstrated a high glare/halo grade. Although optical zone size was not associated with glare or halo, subjective patient satisfaction was greater with a 5.0-mm optical zone than with a 4.5-mm optical zone.
Centration is an important surgeon-controlled variable in excimer laser PRK. Decentration of excimer laser refractive procedures was found to be nonrandom and may be influenced by preoperative pupil management. Moreover, the amount of decentration may influence clinical outcomes. Improved techniques and centering procedures on nonmiotic pupils may improve future results.
确定接受准分子激光屈光性角膜切削术（PRK）患者的光学区偏心量，并评估偏心量和光学区大小与临床结果之间的关联。
使用计算机辅助角膜地形图分析185例PRK术后患者的光学区对中情况。对五个研究中心之间的偏心情况进行比较。评估临床结果与手术偏心量和光学区大小之间的关联。
相对于瞳孔中心的偏心量范围为0.00至1.44毫米（平均0.46毫米）：21.8%的偏心量为0.25毫米或更小，42.5%大于0.25毫米且小于或等于0.50毫米，97.1%小于或等于1.00毫米。在双眼，相对于瞳孔中心的平均偏心量位于鼻下。五个研究中心之间的偏心量存在显著差异。偏心量与预期屈光矫正、角膜散光变化和患者满意度相关。偏心量越大，术后裸眼视力有变差的趋势，但与最佳矫正视力、可预测性或屈光性散光无关。未发现偏心量与眩光/光晕分级之间存在显著关系；然而，偏心量为1.00毫米或更大的6例患者中有3例表现出高眩光/光晕等级。尽管光学区大小与眩光或光晕无关，但光学区为5.0毫米时患者主观满意度高于4.5毫米时。
在准分子激光PRK中，对中是一个重要的由手术医生控制的变量。发现准分子激光屈光手术的偏心是非随机的，可能受术前瞳孔管理的影响。此外，偏心量可能影响临床结果。改进技术和针对非缩瞳瞳孔的对中程序可能改善未来的结果。
