There are two main types of trigonoscopes used in clinical practice, one is the ordinary trigonoscope and the other is the laminated trigonoscope, which is made into a membrane. The former is suitable for the use of small degree strabismus, and the latter is suitable for the use of large degree strabismus. 1, the use of small degrees of common strabismus: small degrees of strabismus adults without clinical symptoms can not need to wear. It is suitable for patients with small degree strabismus combined with diplopia, inability to focus, visual fatigue, etc. The initial prescription can start with a lower degree of strabismus. Gradually adapt. Early wear will be slightly uncomfortable, should gradually adapt to, from stationary start, gradually increase the amount of activity. It is easier to read than to walk, and it is easier to adjust to lower degrees than to higher degrees. Doctors and optometrists need to instruct patients on proper use and adaptation. No more than 10-15 prism degrees or less is preferred. The effect is judged by the relief of clinical symptoms. 2, paralytic strabismus with diplopia or trauma-induced extraocular muscle dysfunction. 3.Undercorrection or overcorrection after strabismus surgery, especially suitable for those with diplopia. 4.For small degrees of paralytic strabismus, especially with head position, or trial wear before surgery. Or surgery observation waiting period. Or for those who are temporarily unsuitable for surgery but wish to correct their head position. The use of pressed trigeminal lenses 1 method to correct and relieve micro strabismus, common strabismus, and strabismus correction after overcorrection and undercorrection by pressing the corresponding degree of membrane trigeminal lenses on the frame lens, as in the case of ordinary optical trigeminal lenses. However, it can also be used for larger diopters.