Department of Ophthalmology, Lund University, Malmö University Hospital, Malmö, Sweden.
Acta Ophthalmol. 2011 Dec;89(8):749-54. doi: 10.1111/j.1755-3768.2009.01852.x. Epub 2010 Mar 17.
To evaluate: (i) the relationship between intraocular pressure (IOP) reduction attained with a fixed treatment protocol and the untreated IOP level; (ii) the consistency of IOP reduction over time; and (iii) whether there is a threshold pretreatment IOP level below which IOP reduction might be less effective. Results are based on 128 patients with glaucoma with field defects, who were randomized to the treatment arm of the Early Manifest Glaucoma Trial (EMGT).
The EMGT fixed treatment protocol consisted of 360° laser trabeculoplasty and topical betaxolol eye drops B.I.D. Treatment was unchanged as long as progression did not occur. Analyses assessed the initial IOP reduction after 3 months and also the mean reduction based on all follow-up values; IOP changes over time were evaluated with linear regression analysis. Factors influencing initial and mean IOP reduction were also explored using linear models.
Mean age at baseline was 68 years, and untreated baseline IOP ranged from 13 to 30.5 mmHg. On average, eyes with higher baseline IOP experienced larger pressure reductions than eyes with lower baseline IOP, whether expressed in mmHg or as percentages. Each mmHg of higher baseline IOP was associated with approximately 0.6 mmHg larger IOP reduction. IOP changed little over time, with 66% of patients changing less than 0.5 mmHg/year, and only 13% (17/128) changing >1.0 mmHg/year. The treatment protocol did not achieve any average IOP reduction in eyes with baseline pressures ≤ 15 mmHg. Factors related to more IOP reduction at 3 months were higher baseline IOP and positive refractive error, while higher baseline IOP and male gender (more reduction) and cardiovascular disease history (less reduction) were associated with mean IOP on treatment.
With a fixed treatment protocol, the IOP reduction achieved depended very strongly on baseline untreated IOP levels. There seemed to be a lower threshold around 15 mmHg, where therapy did not result in any reduction of IOP. Our results suggest that when effects of IOP-lowering treatment are reported, whether expressed in mmHg or as a percentage of untreated pressure levels, the baseline IOP levels should be specified as well.
评估（i）采用固定治疗方案获得的眼压（IOP）降低程度与未治疗的IOP 水平之间的关系；（ii）IOP 随时间降低的一致性；（iii）是否存在一个治疗前 IOP 阈值，低于该阈值，IOP 降低的效果可能较差。结果基于 128 例患有视野缺损的青光眼患者，他们被随机分配到早期显性青光眼试验（EMGT）的治疗组。
EMGT 固定治疗方案包括 360°激光小梁成形术和局部贝他洛尔眼药水 BID。只要没有进展，治疗就不变。分析评估了 3 个月后的初始 IOP 降低，以及基于所有随访值的平均降低；使用线性回归分析评估 IOP 随时间的变化。还使用线性模型探讨了影响初始和平均 IOP 降低的因素。
基线时的平均年龄为 68 岁，未治疗的基线 IOP 范围为 13 至 30.5mmHg。平均而言，基线 IOP 较高的眼睛比基线 IOP 较低的眼睛经历了更大的压力降低，无论是以 mmHg 还是百分比表示。基线 IOP 每升高 1mmHg，平均 IOP 降低约 0.6mmHg。IOP 随时间变化很小，66%的患者每年变化小于 0.5mmHg，只有 13%（17/128）每年变化大于 1.0mmHg。治疗方案在基线压力≤15mmHg 的眼睛中未实现任何平均 IOP 降低。在 3 个月时IOP 降低更多的相关因素是较高的基线 IOP 和正屈光不正，而较高的基线 IOP 和男性（更多降低）以及心血管疾病史（更少降低）与治疗期间的平均 IOP 相关。
采用固定治疗方案，所实现的 IOP 降低程度非常强烈地依赖于未治疗的基线 IOP 水平。在 15mmHg 左右似乎存在一个较低的阈值，在这个阈值下，治疗不会导致任何 IOP 降低。我们的结果表明，当报告降压治疗的效果时，无论是以 mmHg 还是未治疗压力水平的百分比表示，都应指定基线 IOP 水平。
