Corneal Scar

About: Corneal Scar is a research topic. Over the lifetime, 454 publications have been published within this topic receiving 7367 citations.

Method of, and apparatus for, surgery of the cornea

Abstract: A laser-based method and apparatus for corneal surgery. The present invention is intended to be applied primarily to ablate organic materials, and human cornea in particular. The invention uses a laser source which has the characteristics of providing a shallow ablation depth (0.2 microns or less per laser pulse), and a low ablation energy density threshold (less than or equal to about 10 mJ/cm 2 ), to achieve optically smooth ablated corneal surfaces. The preferred laser includes a laser emitting approximately 100-50,000 laser pulses per second, with a wave-length of about 198-300 nm and a pulse duration of about 1-5,000 picoseconds. Each laser pulse is directed by a highly controllable laser scanning system. Described is a method of distributing laser pulses and the energy deposited on a target surface such that surface roughness is controlled within a specific range. Included is a laser beam intensity monitor and a beam intensity adjustment means, such that constant energy level is maintained throughout an operation. Eye movement during an operation is corrected for by a corresponding compensation in the location of the surgical beam. Beam operation is terminated if the laser parameters or the eye positioning is outside of a predetermined tolerable range. The surgical system can be used to perform surgical procedures including removal of corneal scar, making incisions, cornea transplants, and to correct myopia, hyperopia, astigmatism, and other corneal surface profile defects.

Bacterial keratitis early after corneal crosslinking with riboflavin and ultraviolet-A.

Abstract: We report a case of bacterial keratitis 3 days after corneal crosslinking for keratoconus. The patient complained of increasing pain and redness combined with blurred vision in the treated eye starting on the first postoperative day. Clinical examination showed multiple stromal infiltrations and moderate anterior chamber inflammation. Corneal scraping revealed an Escherichia coli infection, which was successfully treated with fortified tobramycin and cephazolin eyedrops for several weeks. This is the first report of a case of rare postoperative complication resulted in an avascularized corneal scar and permanent reduction of the visual acuity.

Clinical Use of the 193-nm Excimer Laser in the Treatment of Corneal Scars

Abstract: • Phototherapeutic keratectomy using a 193-nm excimer laser was performed at four centers on 33 sighted patients with corneal opacity and/or irregular astigmatism. Pathologic conditions included anterior stromal and superficial scarring from postinfectious and posttraumatic causes, including inactive herpes simplex virus, anterior corneal dystrophies, recurrent erosions, granular dystrophy, and band keratopathy. Most patients received peribulbar anesthesia and underwent removal of the epithelium prior to laser ablation. A majority of patients had a reduction in the amount of corneal scarring and approximately half had improved visual acuity. No intraocular reaction or changes in endothelial counts were seen, and some patients avoided the need for penetrating keratoplasty. Reepithelialization usually occurred within 4 or 5 days and we noted no significant scarring secondary to use of the laser. It was difficult to eliminate preexisting irregular astigmatism despite the use of surface modulators, such as methylcellulose. A hyperopic shift secondary to corneal flattening was encountered in approximately 50% of the patients. A combination of myopic ablation, followed immediately by a secondary hyperopic steepening, may minimize this refractive change. The 193-nm excimer laser is an effective new tool in the treatment of selected patients with superficial corneal opacity from a variety of conditions.