Ophthalmic Examination Methods

OCT is a non-contact biological tissue imaging technology [7]. The scan mode of GCC (retinal ganglion cell complex in macular region) was selected. The GCC scan consists of 15 vertical scans covering a range of 7 mm². The scanning center was 1 mm temporal to the macular fovea so as to better cover the temporal area. In addition, the scan also included a horizontal scan at the center to note the depth and perform a fovea search. With the fovea as the center, GCC-a is the average thickness, GCC-s is the upper average thickness, and GCC-i is the lower average thickness.

A Humphrey – 750 automatic perimeter (Germany Zeiss company) was used for visual field inspection. Program settings were: Center 30-2 inspection procedures, white Stimulus III, 31.5 asb as background brightness, physiological blind spot gaze monitoring. After the whole process of computer processing, the visual field inspection result is given, which mainly includes mean visual field defect (MD) and pattern standard deviation (PSD). The difference from the average threshold of all detection sites and the mean of the same age patients without eye disease was MD, and it reflects the degree of decline in visual average sensitivity due to various reasons. MD may be due to refractive interstitial opacity or optic nerve damage. Detection of MD alone cannot judge specific eye diseases. Therefore, it is necessary to combine another indicator, namely PSD. PSD reflects the visual field irregularity caused by local visual field defect. This PSD result can filter out the decrease of visual sensitivity caused by refractive interstitial opacity. Therefore, this study combined MD and PSD for analysis.

The patient was placed in supine position, surface anesthesia was performed on the treated eye, we placed a bottomless eye cup in the conjunctival sac and injected sterile water for injection, then a UBM probe scanned vertically near the limbus [8]. Scanning methods: The limbal cornea has 4 quadrants throughout the week, all of which were scanned laterally and radiographically, focused on the observation of the anterior chamber angle and measured the anterior chamber depth. The anterior chamber depth could be measured, analyzed, and stored by the obtained images. The parameters of anterior chamber angle were defined as: taking the scleral process as the center of the circle, made a circle with a radius of 500 μm, then the degree of the angle formed by the intersection of the circle with the corneal endodermis and the iris anterior surface and the line between the scleral process was the degree of the anterior chamber angle.

We used a non-contact tonometer (Canon) for IOP measurement [9]. The subjects were not allowed to eat food or take medicine that affected IOP 1 week before the measurement, and were told not to drink alcohol. On the day of the measurement, the subject normally ate and drank water. All examinations were done by the same doctor each time the patient’s sitting IOP was measured; it measured 3 times for each eye and we took the average value. We measured IOP at 5: 00, 7: 00, 10: 00, 14: 00, 18: 00, 22: 00, then took the mean value. At 24 h, the mean IOP was measured before surgery and 1 day, 1 week, 2 weeks, 1 month, and 3 months after surgery.