PubMed1977
The Pneumatonometer of Langham was used to record the effect upon intraocular pressure of a range of eyelid specula, lid sutures, and eyelid clamps. It was concluded that all methods tested produced a rise in intraocular pressure in most patients, and that the degree of rise was related to the degree to which the eyelids were separated. It was therefore recommended that a method of eyelid retraction which allows adjustment is to be preferred, and that specula which do not allow this, such as the Barraquer speculum, are not to be recommended. Traction upon the superior rectus suture was shown to lead to a considerable rise in intraocular pressure and this should therefore be avoided unless strictly necessary. The traction produced by two limbal sutures pulling tangentially downwards, rotates the eye downwards for intraocular surgery without inducing a rise in intraocular pressure. Measurement of intraocular pressure in the operating theatre is recommended in order to ascertain whether the method used to retract the eyelids or to rotate the eye to the field of surgery is having an adverse effect.