Fasano A P, Moreira H, McDonnell P J, Sinbawy A
Doheny Eye Institute, Los Angeles, CA 90033.
Ophthalmology. 1991 Dec;98(12):1782-5. doi: 10.1016/s0161-6420(91)32050-5.
A reproducible model of an irregular corneal surface was developed to test the ability of the excimer laser to treat such surfaces. Using a 193-nm argon fluoride excimer laser set at a fluence of 160 mJ/cm2, repetition rate of 10 Hz, and 185 pulses, fresh de-epithelialized pig eyes underwent phototherapeutic ablations through a piece of stainless steel wire screen that masked the cornea. This yielded an uneven corneal surface in a grid-like pattern, with the peaks 50 microns higher than the troughs. The eyes then underwent further treatment in an attempt to smooth the center of the irregularity. Hydroxypropyl-methylcellulose 0.3% protected the valleys in 12 eyes; 2 eyes were ablated without a protecting fluid. The same laser, at the above noted settings, was used, except that both 2 Hz and 10 Hz frequencies were used. Immediately after treatment, the eyes were processed for scanning electron microscopy. The eyes treated at 2 Hz showed less surface irregularity than did those treated at 10 Hz. The eyes treated without a protecting fluid, regardless of repetition rate, had the greatest irregularities. This model is simple and reproducible, and the authors' results suggest that modifying the repetition rates of the excimer laser can influence its effectiveness in smoothing irregular corneas.
开发了一种可重复的不规则角膜表面模型，以测试准分子激光治疗此类表面的能力。使用波长为193纳米的氟化氩准分子激光，设置能量密度为160毫焦/平方厘米、重复频率为10赫兹、脉冲数为185次，新鲜去上皮的猪眼通过一块遮蔽角膜的不锈钢丝网进行光治疗性消融。这产生了呈网格状的不均匀角膜表面，其峰值比谷值高50微米。然后对这些眼睛进行进一步治疗，试图使不规则区域的中心变平滑。0.3%的羟丙基甲基纤维素保护了12只眼睛的凹谷；2只眼睛在没有保护液的情况下进行了消融。使用相同的激光，设置与上述相同，只是使用了2赫兹和10赫兹两种频率。治疗后立即对眼睛进行扫描电子显微镜检查。以2赫兹频率治疗的眼睛比以10赫兹频率治疗的眼睛表面不规则性更小。无论重复频率如何，在没有保护液的情况下治疗的眼睛不规则性最大。该模型简单且可重复，作者的结果表明，改变准分子激光的重复频率会影响其使不规则角膜变平滑的效果。
