这种病发生在眼部排水渠道完全堵塞时，而且症状明显——视力模糊、头痛、眼痛并作呕。
This happens when the drainage canals become completely blocked, and symptoms can be vivid - blurred vision, headaches, eye pain and nausea.
最常见的是开角型青光眼（open-angle glaucoma）。 患这种病的眼部排水渠道被部分堵塞。
The most common is primary open-angle glaucoma, in which the eye’s drainage canals are partly clogged.
在另一种变通方式中，用渠道代替畦埂，堵塞渠道，进行灌溉。
In another variation, ditches replace the ridge between borders and the area between is irrigated by blocking the ditches.
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