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Treatment of patients with glaucoma depends on accurate diagnosis. The diagnosis of glaucoma patients, like other diseases, is based on a comprehensive analysis of the medical history, clinical manifestations and examination findings. Li Hua, Ophthalmology Department, Yongchuan Hospital, Chongqing Medical University
In suspected patients, IOP should be measured first. An IOP greater than 3.20kPa (24mmHg) is pathologically high IOP, but a high primary IOP cannot diagnose glaucoma, while a normal primary IOP cannot exclude glaucoma. This is because IOP fluctuates periodically throughout the day. Daily IOP fluctuations greater than 1.07 kPa (8 mmHg) are considered pathological IOP. In normal people, the pressure in both eyes is close to each other, but if the pressure difference between the two eyes is greater than 0.67kPa (5mmHg), it is also pathological IOP. Next, the fundus should be examined to observe the optic disc changes. The optic disc changes in glaucoma have certain specificity and have important clinical value. C/D greater than 0.6 or bilateral C/D difference greater than 0.2 is abnormal; thinning of the optic disc rim, often accompanied by uneven width and tangency of the disc rim, indicates a decrease in the number of optic nerve fibers along the optic disc; changes in the optic disc vasculature, manifested by hemorrhage at the edge of the optic disc, vascular hollowing, nasal displacement of the optic disc vessels and The optic disc vascular changes, which show hemorrhage at the edge of the optic disc, vessel hollowing, nasal displacement of the optic disc vessels and central retinal artery pulsation. In addition, funduscopic examination can visualize retinal nerve fiber layer defects, which are considered to be one of the early diagnostic indications of glaucoma because they can precede visual field defects.
Visual field examination is of great value in the diagnosis of glaucoma. This is because it represents damage to the optic nerve. The common clinical types of visual field defects are: generalized reduction of visual threshold, bowed defect, nasal step, vertical step, temporal scalloped defect, and central and temporal insular visual field.
With the above tests, we can diagnose glaucoma, but we should also determine the type of glaucoma before starting treatment. First, the anterior atrial angle is examined, and those with an open angle are considered open-angle glaucoma, while the opposite is true for closed-angle glaucoma. If the diagnosis of glaucoma classification is still difficult through the atrial angle examination, the atrial fluid coefficient (C value) can be checked. a C value less than 0.1 is pathological, and a pressure to fluid ratio (Po/C) greater than 150 is pathological, mainly in open-angle glaucoma. However, it should be noted that the C-value and pressure-fluency ratio can also be abnormal after recurrent episodes of closed-angle glaucoma. In addition, we can select some excitation tests for some suspected glaucoma to assist in the diagnosis.
The diagnosis of secondary glaucoma starts with ocular or systemic lesions and of course high intraocular pressure and optic nerve damage. Atrial angle microscopy is performed to understand whether the cause of high IOP is atrial angle closure or trabecular filtration dysfunction to diagnose whether it is secondary open-angle glaucoma or closed-angle glaucoma.