Management of partially absorbed white soft cataract post penetrating injury to eye.

Background: A measurable burden to the emergency ophthalmology department is represented by ocular trauma in pediatric patients. Traumatic cataracts still result in visual disability despite great advancements in diagnostic and treatment methods. Cataract surgery with intraocular lens (IOL) implantation aids in the improvement of visual acuity in such cases. Duration of trauma is an important prognostic factor for recovery of visual acuity before amblyopia sets in young patients with penetrating ocular injury. Purpose: This video deals with the management of a case of partially absorbed traumatic cataract in a scenario of an old and neglected penetrating injury. This case had a corneal scar, ruptured anterior lens capsule, and posterior synechiae formation between the posterior pigmented epithelium of the iris and the lens capsule. Synopsis: In a case of penetrating ocular injury, one should always suspect violation of posterior lens capsule, weakened or broken zonules and retained intraocular foreign body. In this case, a circular capsulorhexis is difficult to attain. After staining the capsule with trypan blue dye, viscoelastic substance is instilled in the anterior chamber to have good control over the rhexis and to avoid rhexis run out. In case the rhexis runs off to the equator, a pair of Vannas scissors is used to cut the extended flap. The cataract is partially absorbed, white and soft in nature and is easily mobilized from the bag and eaten up via phacoaspiration. Before implantation of posterior chamber intraocular lens (PCIOL) in the sulcus, posterior synechiae are released by swiping a cyclodialysis spatula in the sulcus area. Visual axis is cleared by giving nicks in the posterior capsule to remove the central dense posterior plaque. Automated anterior vitrectomy is done and a three-piece PCIOL is implanted safely in the ciliary sulcus. Retained viscoelastic substance is washed, intracameral antibiotic is instilled, and the anterior chamber is subsequently formed via stromal wound hydration. Highlights: Through this video, we tried to show how one should proceed with phacoaspiration with intraocular lens implantation in a case of traumatic cataract post penetrating injury in a sequential manner. Video Link: https://youtu.be/20DbYUn_Fd8.

Compact two-dimensional coarse-positioner for scanning probe microscopes.

We report on the design and fabrication of a compact two-dimensional xy-positioner for scanning probe microscopes. This positioner uses three piezoelectric bimorphs in flexing or length-change mode by appropriate selection of electrodes and voltage polarities. One end of these bimorphs is fixed to a rectangular metal frame while on each of the free ends two sapphire disks are fixed which can slide against the polished plates of a platform movable in the xy-plane. For moving the platform by one step, the bimorphs are deformed sequentially in one mode and they are brought back to their undeformed state simultaneously. The motion of the positioner has been tested with an optical microscope and a homemade scanning tunneling microscope.