The slit ruler is a positive position training instrument, which is composed of a support, a sliding ruler, a sliding plate and a visual mark card. When a single hole sliding plate is used, the visual axis intersects before the visual mark card, resulting in the collection demand; When using a double hole skateboard, the visual axes do not intersect or intersect behind the visual mark card, resulting in divergent demand. The trainer only needs to replace the single hole skateboard with a double hole skateboard, and the visual training will be converted from collective training to scattered training.

When training the convergence and dispersion function by the slit ruler, it does not start from 0 as the red and green stereogram, so its training is more difficult. The slit ruler is equipped with two kinds of sliding plates, a single hole (Bo) and a double hole (BI), and 12 different picture cards (2.5 △ ~ 30 △). The card of the slit ruler includes plane fusion image and stereoscopic view. Each picture has de suppression clues and adjustment control points (above the circle seen by one eye) ×,the other eye sees dots. Each picture card has an eccentric concentric circle, which can play the role of stereoscopic image. Once the image is melted, You will find that the inner circle is more convex (set) or the outer circle is more convex (divergence). These stereoscopic icons and disinhibition cues are very helpful for the examiner to detect whether the patient is trained correctly. The design distance of the slit ruler is 40cm, and every 4mm separation at 40cm is equivalent to 1 △ prism effect, so the distance between the two images on the first picture card is 1cm, and the prism effect is 2.5 △ prism effect.

① Put the special visual specimen slide plate at the "0" position, insert the visual specimen, starting from card 1. Slide the single hole sliding plate to the position of 1.

② Ask the trainer to place the nose tip on the rear top of the sliding ruler. Cover the patient's left eye and right eye alternately. The patient should report the visual mark seen in the left eye as a band“ ×” For the sight mark, the sight mark seen by the right eye is a sight mark with "·". If the corresponding sight mark cannot be seen by covering both eyes alternately, move the single hole sliding plate back and forth until the corresponding sight mark position can be seen by both left and right eyes.

③ Remove the cover and ask the patient what they see in both eyes.

④ Patients may report diplopia, monocular suppression, or fusion of binocular visual markers into a single pattern.

⑤ Explain to the patient that the training goal is to obtain a single clear pattern.

⑥ If the patient cannot fuse, you can try to suggest that the patient feels that the visual target is close to himself.

⑦ If there are still difficulties, you can try to use the guide rod to help. Place the guide rod behind the crack baffle and ask the patient to look at the guide rod. The patient will report seeing a guide rod and a pattern. Once the patient obtains fusion, the guide rod can be removed. After several times of training, the patient will fuse the patterns of left and right eyes without the help of the guide rod.

⑧ If the patient reports fusion, ask the patient about the clarity of the pattern and whether the pattern has a sense of depth.

⑨ Ask the patient to keep fusion, count to 5, move his eyes away from the training card for a moment, and then look at the training card again to obtain fusion as quickly as possible.

⑩ Repeat the above process 5 times for each training card, replace the training card, adjust the position of single crack baffle, and repeat the above steps until card 12. The goal of training is to clearly integrate 12 card pictures every time. If you can't complete it successfully, don't be discouraged. It takes a while of training to complete this process.

Train for 2 minutes and rest for 30 seconds. Repeat multiple times. Make appropriate adjustments according to the ability of each patient.

① Put the special visual specimen slide plate at the "0" position, insert the visual specimen, starting from card 1. Slide the double hole sliding plate to the position of 1.

② Ask the trainer to place the nose tip on the rear top of the slide ruler (as shown in Fig. 1-4-19). Cover the patient's left eye and right eye alternately. The patient should report the visual band seen in the right eye“ ×” Visual mark: the visual mark seen by the left eye is a visual mark with "·". If the corresponding visual mark cannot be seen by alternating covering of both eyes, move the double hole sliding plate back and forth until the corresponding visual mark position can be seen by both left and right eyes.

③ Remove the cover and ask the patient what they see in both eyes.

④ Patients may report diplopia, monocular suppression, or fusion of binocular visual markers into a single pattern.

⑤ Explain to the patient that the training goal is to obtain a single clear pattern. If the patient can't fuse the two visual markers into one, insert a fixation rod into the "a" hole on the sliding plate, and the patient can look at the top of the fixation rod above the front of the visual specimen. The lower sight mark can be indirectly fused within the "field of view". After fusion, the fixation eye position gradually moves backward and shifts to the fusion line of sight.

⑥ Once the clear fusion image is completed, ask the patient to turn away from the visual specimen, and then look at the visual specimen again to obtain a clear fusion image.

⑦ The hole size and position of the double hole sliding plate are marked on each page of the visual specimen. Instruct the patient to read these instructions before training.

⑧ The purpose of training is to clearly integrate the pictures of visual markers 1 ~ 7 every time. If it cannot be completed smoothly, don't be discouraged. This process requires some time of training.

Train for 2 minutes and rest for 30 seconds. Repeat multiple times. Make appropriate adjustments according to the ability of each patient.

Indications: Binocular convergence and divergence dysfunction

(1) Single Hole Sliding Plate

(2) Double Hole Sliding Plate