Bhandari A, Crabb D P, Poinoosawmy D, Fitzke F W, Hitchings R A, Noureddin B N
Moorfields Eye Hospital, London, England.
Ophthalmology. 1997 Jul;104(7):1131-7. doi: 10.1016/s0161-6420(97)30172-9.
The effect of intraocular pressure-lowering surgery on the rate of visual field progression in normal-tension glaucoma (NTG) was studied.
Seventeen patients with NTG who underwent trabeculectomy in one eye for worsening visual field loss were included in the first part of the study. All patients had Humphrey 24-2 visual fields at the rate of 2-3 fields per year. Pointwise linear regression analysis of the visual field data was done separately for the preoperative and postoperative periods. This was performed for both operated and fellow eyes. The mean slope (MS), which indicates rate of visual field progression, was calculated. Change in MS was correlated with change in intraocular pressure (IOP). For the second part of the study, 11 patients who had a minimum of 4 visual fields and 18 months of follow-up before surgery were identified. Using the preoperative fields, the rate of sensitivity loss for each visual field location in the operated eye was ascertained for every patient. This rate of loss was extrapolated to generate the expected visual fields, assuming an unchanged rate of progression. The mean sensitivity of the expected visual field was compared with that of the actual field at the last follow-up.
The MS in the operated eyes improved from -2.97 +/- 3.21 (mean +/- SD) in the preoperative period to 0.53 +/- 3.83 (P < 0.005; Student's t test) postoperatively. In the fellow eyes the MS changed from -1.78 +/- 2.55 to -1.43 +/- 3.01 (P = 0.754). There was a weak correlation between change in MS and percentage IOP decrease (correlation coefficient 0.39). The difference in mean sensitivity between the expected and actual visual fields was -3.72 dB (P = 0.002), and was better in the actual field.
In this study, surgical lowering of IOP resulted in a slower rate of visual field loss in the operated eye.
研究眼压降低手术对正常眼压性青光眼（NTG）视野进展速率的影响。
研究的第一部分纳入了17例因视野缺损恶化而单眼接受小梁切除术的NTG患者。所有患者每年以2 - 3次的频率进行Humphrey 24 - 2视野检查。分别对术前和术后阶段的视野数据进行逐点线性回归分析。对手术眼和对侧眼均进行此项分析。计算出表示视野进展速率的平均斜率（MS）。MS的变化与眼压（IOP）的变化相关。在研究的第二部分，确定了11例术前至少有4次视野检查且随访时间不少于18个月的患者。利用术前视野，为每位患者确定手术眼每个视野位置的敏感度丧失速率。假设进展速率不变，外推该丧失速率以生成预期视野。将预期视野的平均敏感度与最后一次随访时的实际视野平均敏感度进行比较。
手术眼的MS从术前的-2.97±3.21（均值±标准差）改善至术后的0.53±3.83（P < 0.005；Student t检验）。对侧眼的MS从-1.78±2.55变为-1.43±3.01（P = 0.754）。MS的变化与眼压降低百分比之间存在弱相关性（相关系数0.39）。预期视野与实际视野的平均敏感度差异为-3.72 dB（P = 0.002），实际视野的情况更好。
在本研究中，手术降低眼压导致手术眼的视野丧失速率减慢。
