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K V Chalam, Hafeez Dhalla, Scott Russo; Evaluation of self stabilizing goniolens for intraoperative gonioscopy during microstent glaucoma procedures. Invest. Ophthalmol. Vis. Sci. 2018;59(9):5883.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate self stabilizing gonioscopy lens system, that provides a 360° real image of the anterior chamber angle structures without the use of reflective surfaces.
The lens system has three specific lens features. The lens group has a concave posterior surface [Radius of curvature (ROC) = 7.8 mm],for placement on the patient’s cornea. As the ROC of the lens is almost equal to the ROC of the anterior corneal surface, a coupling agent is not required. The group I lens system consists of a biconcave lens, and a prism lens sub–group. This group acts to direct light rays originating at the anterior chamber angle towards the prism lens group II for focusing through internal reflection. The lens system collimates the light rays.Second feature of the lens is truncation superiorly. This feature is added to facilitate introduction of surgical instruments during cataract surgery through corneal incision. Cord length of the lens is 6mm superiorly.Third feature of the lens include three separate foot plates 90 degrees apart, 3mm in length and 2 mm in width. They provide additional stability and prevent rotation of lens during gonioscopy. Foot plates are placed at 40 degrees in increase stability and prevent rotation.The prism lens sub–group is integrated at 31 degrees and measure 10mm in height. The group II focuses the light rays and provides magnification of the angle. Image contrast of the lens is further improved by seamless fusion of both elements. This prevents superfluous and aberrant light from propagating the gonioscopic lens system thus improving the image quality from the anterior chamber angle.
The lens system provides real and erect panoramic image of the angle.Gonioscopic image of the angle is clear and without distortion. Surgical instruments can be safely introduced into anterior chamber without interfering with the gonioscopic image. As lens is self retaining, intraoperative placement of microstent is relatively easy with the assistance of counter pressure with scleral indentation (facilitated with unused hand of surgeon) or surgical assistant
This newly designed gonioscpy lens provides a real erect panoramic view of the whole 360°s of the anterior chamber angle without rotating the lens and facilitates gonioobservation and surgery. Self retaining property improved both accuracy and speed of placement of microsurgical stent intraoperatively.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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