Ridder William H, Rouse Michael W
Southern California College of Optometry, 2575 Yorba Linda Blvd, Fullerton, CA 92831, USA.
Doc Ophthalmol. 2007 May;114(3):135-45. doi: 10.1007/s10633-007-9048-y. Epub 2007 Feb 20.
Amblyopic patients, or their parents, often want to know the potential for success before committing to treatment. Recent reports have indicated that the pattern visual evoked potential (pVEP) can be used as a predictor of the success of amblyopia therapy. Unfortunately, these studies did not determine if acuity estimates from pVEPs could accurately predict the acuity post-treatment. Furthermore, pVEPs are not always practical to obtain because of the time necessary to acquire the data. Sweep VEPs (sVEP) offer the advantage of rapidly estimating visual acuity in amblyopic patients. In this retrospective study, the relationship between sVEP acuities measured pre-amblyopic therapy and Snellen acuities measured post-amblyopic therapy was determined.
Seventeen patients with amblyopia were studied. Monocular sVEP and Snellen acuities were determined pre-amblyopic therapy and Snellen acuities were determined post-amblyopic therapy. An Enfant 4010 computer system was used to produce the stimuli, record the VEPs, and extrapolate the acuity. The stimuli were horizontally oriented, sine wave gratings (11 spatial frequencies from 2 to 24 cpd) with a contrast of 80%, counterphased at 7.5 Hz. Standard VEP recording techniques were employed. Therapy consisted of the full refractive correction and occlusion combined with active vision therapy.
The patients demonstrated a significant improvement in pre- to post-amblyopic therapy Snellen acuities (P < 0.00001). The intraclass correlation coefficient (r (i)) between the pre-therapy sVEP acuities and the post-therapy Snellen acuities was 0.73. A paired t-test did not find a significant difference between the two sets of data (P = 0.94). For the amblyopes in this study, the average difference (+/-SD) in the sVEP acuity estimate and the final Snellen visual acuity was +0.002 +/- 0.123 logMAR acuity lines.
The results indicate that pre-amblyopic therapy sVEP acuity can be a good predictor of post-amblyopic therapy Snellen acuity.
弱视患者或其家长在决定接受治疗前，通常想了解治疗成功的可能性。近期报告表明，图形视觉诱发电位（pVEP）可作为弱视治疗成功的预测指标。遗憾的是，这些研究并未确定pVEP得出的视力估计值能否准确预测治疗后的视力。此外，由于获取数据所需时间，pVEP并非总能实际应用。扫描视觉诱发电位（sVEP）具有快速估计弱视患者视力的优势。在这项回顾性研究中，确定了弱视治疗前测量的sVEP视力与弱视治疗后测量的斯内伦视力之间的关系。
对17例弱视患者进行研究。在弱视治疗前测定单眼sVEP和斯内伦视力，在弱视治疗后测定斯内伦视力。使用Enfant 4010计算机系统产生刺激、记录VEP并推断视力。刺激为水平方向的正弦波光栅（11个空间频率，范围为2至24周/度），对比度为80%，以7.5赫兹进行反相。采用标准的VEP记录技术。治疗包括完全屈光矫正、遮盖以及主动视觉治疗。
患者在弱视治疗前后的斯内伦视力有显著改善（P < 0.00001）。治疗前sVEP视力与治疗后斯内伦视力之间的组内相关系数（r (i)）为0.73。配对t检验未发现两组数据之间存在显著差异（P = 0.94）。对于本研究中的弱视患者，sVEP视力估计值与最终斯内伦视力的平均差异（±标准差）为+0.0（02 ± 0.123对数最小分辨角视力行。
结果表明，弱视治疗前的sVEP视力可作为弱视治疗后斯内伦视力的良好预测指标。
