Baptista Pedro Manuel, Marta Ana Ambrósio, Marques João Heitor, Abreu Ana Carolina, Monteiro Sílvia, Menéres Pedro, Pinto Maria do Céu
Ophthalmology Department, Centro Hospitalar Universitário do Porto, Porto, Portugal.
Instituto de Ciências Biomédicas Abel Salazar, Porto, Portugal.
Clin Ophthalmol. 2021 Feb 19;15:745-758. doi: 10.2147/OPTH.S296744. eCollection 2021.
To describe the tomographic and corneal biomechanical status of a sample of eyes excluded from LVC and to present the differences in biomechanical behavior in relation to cutoffs of clinical- and tomography-based screening methods used in clinical practice.
Observational cross-sectional study including 61 eyes from 32 consecutive patients who were excluded from LVC in our department. Clinical and demographic data were collected from the patients' clinical records. Tomographic data was assessed with a Scheimpflug camera (Pentacam, OCULUS). Ablation depth (µm) and residual stromal bed (µm) were calculated by the WaveLight EX500 laser system software (Alcon, EUA). The corneal biomechanical assessment was made through ultra-high speed Scheimpflug imaging during noncontact tonometry (Corvis ST, OCULUS). Several ectasia risk scores were analyzed.
Mean age was 31.0±6 years old and mean manifest spherical equivalent was -2.01 ± 2.3D. Belin-Ambrósio deviation index was the tomographic parameter with higher proportion of eyes within the ectasia high risk interval. In the biomechanical assessment, more than 95% of eyes met the criteria for ectasia susceptibility in four of the first generation and in two of the second generation parameters. In a cutoff based comparative analysis, eyes with Kmax ≥45.5 D, eyes with VCOMA <0 and eyes with ARTmax ≤350 presented significantly softer corneal biomechanical behavior.
The majority of eyes excluded from LVC in the present study met the criteria for ectasia susceptibility in several biomechanical parameters, validating the clinical and tomographic based screening prior to LVC in our center. Differences found in the biomechanical assessment regarding cutoffs used in clinical practice highlight its differential role in characterizing risk profile of these patients. Tomography should not be overlooked and the integration of all data, including treatment-related parameters, can be the future of risk ectasia screening prior LVC.
描述被排除在准分子激光原位角膜磨镶术（LASIK）之外的一组眼睛样本的断层扫描和角膜生物力学状态，并呈现与临床实践中基于临床和断层扫描的筛查方法阈值相关的生物力学行为差异。
观察性横断面研究，纳入了我科连续32例被排除在LASIK之外的患者的61只眼睛。从患者的临床记录中收集临床和人口统计学数据。使用三维 Scheimpflug 相机（Pentacam，OCULUS）评估断层扫描数据。通过威视 EX500 激光系统软件（爱尔康，美国）计算消融深度（微米）和剩余基质床（微米）。在非接触眼压测量期间，通过超高速 Scheimpflug 成像进行角膜生物力学评估（Corvis ST，OCULUS）。分析了几种扩张风险评分。
平均年龄为31.0±6岁，平均明显球镜等效度为-2.01±2.3D。贝林-安布罗西奥偏差指数是在扩张高风险区间内眼睛比例较高的断层扫描参数。在生物力学评估中，超过95%的眼睛在第一代的四个参数和第二代的两个参数中符合扩张易感性标准。在基于阈值的比较分析中，角膜最大曲率（Kmax）≥45.5 D的眼睛、角膜补偿眼内压（VCOMA）<0的眼睛和最大回弹幅度（ARTmax）≤350的眼睛呈现出明显更软的角膜生物力学行为。
本研究中大多数被排除在LASIK之外的眼睛在几个生物力学参数上符合扩张易感性标准，验证了我们中心在LASIK术前基于临床和断层扫描的筛查。在生物力学评估中发现的与临床实践中使用的阈值相关的差异突出了其在表征这些患者风险特征方面的不同作用。不应忽视断层扫描，整合所有数据，包括与治疗相关的参数，可能是LASIK术前扩张风险筛查的未来方向。
