Alfaqawi Fadi, Pagano Luca, Arbabi Esmaeil M, Romano Vito, Al-Maskari Ahmed, McLean Keri, Czanner Gabriella, Kaye Stephen B
Royal Liverpool University Hospital, Liverpool, UK.
Ophthalmology, Royal Liverpool and Broadgreen Hospitals NHS Trust, Liverpool, UK.
BMJ Open Ophthalmol. 2025 Jan 11;10(1):e001920. doi: 10.1136/bmjophth-2024-001920.
To quantify the effect of cataract surgery on cornea shape.
Patients undergoing cataract surgery with standardised 2.75 mm surgical incisions at 110 degrees with a side port at 50 degrees were included. Repeat biometric measurements were taken before surgery and at 6 weeks on both operated and unoperated fellow eyes. Data were transformed into Long's formalism for analysis. Device-specific measurement error was determined. The main outcome measure was the change in keratometry taking into account the change in keratometry of the unoperated fellow eye. Secondary outcome measures included the variability introduced due to location of the incision.
132 patients were included. The mean change in keratometry of the operated eye was -0.23@111/+0.21@21 (95% CI -1.43@122/+0.04@32 to +1.04@135/+0.30@45). The flattening effect of the surgical incision was greater and more variable than the steepening effect (p<0.01), particularly if the incision was in the flat meridian. Coupling, defined as ratio of the keratometric change in the preoperative meridians of K2 and K1, varied from 0.91 (SD 2.31) for eyes with an incision in the steep meridian, 0.75 (SD 1.81) for an incision in the flat meridian to 0.28 (SD 2.06) when the incision was made in a neutral meridian.
Cataract surgery has a slightly greater flattening than steepening effect on corneal shape. Although the effects are very small and variable with incomplete coupling, it is preferable to place the incision in the steep meridian. Greater emphasis, however, should be placed on eye-specific factors, such as biometry, or patient-related factors to optimise refractive outcomes.
量化白内障手术对角膜形状的影响。
纳入接受白内障手术的患者，手术切口为标准化的2.75毫米，位于110度，侧切口位于50度。在手术前以及术后6周对手术眼和未手术的对侧眼进行重复生物测量。数据转换为朗氏形式进行分析。确定特定设备的测量误差。主要观察指标是考虑未手术对侧眼角膜曲率计测量值变化后的角膜曲率变化。次要观察指标包括因切口位置导致的变异性。
纳入132例患者。手术眼角膜曲率计测量值的平均变化为-0.23@111/+0.21@21（95%可信区间为-1.43@122/+0.04@32至+1.04@135/+0.30@45）。手术切口的扁平效应比变陡效应更大且更具变异性（p<0.01），特别是当切口位于扁平子午线时。耦合定义为术前K2和K1子午线角膜曲率变化的比值，对于切口位于陡峭子午线的眼睛，耦合值为0.91（标准差2.31）；对于切口位于扁平子午线的眼睛，耦合值为0.75（标准差1.81）；当切口位于中性子午线时，耦合值为0.28（标准差2.06）。
白内障手术对角膜形状的扁平效应略大于变陡效应。尽管这些效应非常小且耦合不完全，变异性较大，但将切口置于陡峭子午线更为可取。然而，应更加强调特定于眼睛的因素，如生物测量，或与患者相关的因素，以优化屈光结果。
