Q-Switched neodymium: YAG laser surgery of the vitreous

Fifty-nine eyes underwent vitreous surgery (vitreolysis) with the Q-switched Nd:YAG laser. This was used to cut vitreoretinal bands and membranes in 16 eyes and to clear persistent vitreous opacities in 25 eyes. The use of appropriate specialized contact lenses and modification of the standard slit-lamp delivery system were essential for vitreous YAG laser surgery. Successful results occurred in eyes where the target tissues were located at distances greater than 2 mm from the crystalline lens and the retina. Vision was improved in 18 eyes, unchanged in 40 eyes, and worse in 1. Complications included focal opacities of the crystalline lens in 5 eyes, retinal holes with detachment in 1 eye, and minor retinal hemorrhages in 4. Methods of preventing complications are discussed.Presented at the 1984 meeting of the Club Jules Gonin in Lausanne, Switzerland     

Scalpel neodymium:YAG laser in oculoplastic surgery

In a three-year study, the scalpel Nd:YAG laser was compared with conventional surgery in 18 patients who underwent oculoplastic surgery. The postoperative follow-up was at least eight months. The contact Nd:YAG laser had distinct advantages over conventional surgery in the treatment of vascular orbital tumors, including less perioperative bleeding and a shorter operating time. In other oculoplastic procedures, ten of the 18 patients underwent surgery with the scalpel Nd:YAG laser on one side and conventional surgery on the other side. There was less bleeding, a shorter operating time, and less pain on removal of orbital fat on the laser-treated side. The postoperative scarring was initially more noticeable on the Nd:YAG laser-treated side, but after three months there was no appreciable difference in scar formation between the two sides. The amount of postoperative edema and ecchymosis did not appear to be significantly different with the Nd:YAG laser compared with conventional surgery. Additionally, microscopic evaluation showed minimal charring of tissues with the Nd:YAG laser.     

Triamcinolone-assisted neodymium:YAG laser vitreolysis.

Triamcinolone acetonide was injected into the vitreous cavity to treat a case of cystoid macular edema. After the injection, slit-lamp examination was performed and the vitreous strands adhered to the remaining edge of the posterior capsule were clearly visualized. The strands were dissected with neodymium:YAG (Nd:YAG) laser shots. A technique that can be used to facilitate diagnosis and Nd:YAG laser dissection of vitreous strands in cases with complications of adhesion of vitreous strands into anterior segment structures is described.     

Phacoemulsification and vitrectomy with the erbium:YAG laser and phacoemulsification with the neodymium:YAG laser

There are an increasing number of possible applications for the use of Erbium:YAG and Neodymium:YAG lasers in opthalmology. Laser-phacoemulsification as well as Erbium-laser vitrectomy is of major interest. We report on the underlying technology and more than 1-year-experience using the PHACOLASE (Asclepion-Meditec, Jena, Germany, 10–100 Hz frequency, 5–50 mJ single pulse energy) for phacoemulsification and pars plana vitrectomy and the Lyla-Dodick laser photolysis (A.R.C. Laser, Eckental-Forth, Germany, 1–20 Hz, up to 8 mJ single pulse energy). The Erbium:YAG-laser as well as the Neodymium:YAG-laser enabled us to extract lenses with up to medium hard nuclei. Moreover, the Erbium laser enabled fast vitrectomy with little mechanical traction. In many of our initial surgical operations we had to change to mechanical vitrectomy due to initial technical problems. No new complications occurred intra- or postoperatively. The handpiece worked well in removing vitreous bodies, but was not feasable for cutting membranes. Modified handpieces for this purpose are under development.     

Treatment of vitreous floaters with neodymium YAG laser.

Fifteen cases of vitreous floaters with serious psychological reactions have been collected. By using a direct ophthalmoscope, causal vitreous opacities were detected. The opacities were photodisrupted with neodymium YAG laser, using energy levels of 5 to 7.1 mJ and total energy 71 to 742.0 mJ. Symptoms completely disappeared immediately after treatment in all 15 cases. There were no intraoperative or postoperative complications noted during a follow up period of at least 1 year. To our knowledge, the use of neodymium YAG laser to treat vitreous floaters has not been previously described. Our initial experience indicates that the treatment is simple, safe, and effective.     

In vitro studies with a pulsed neodymium/YAG laser.

The relationships between the destructive effects of Q-switched Nd/YAG laser pulses and a number of experimental parameters were studied for various target materials including in particular excised, fixed samples of human trabecular meshwork. The laser parameters altered were the pulse energy, the convergence angle of the focused beam, and the position of the focus of the beam relative to the target's axial position. The main finding was that it was possible to make deep holes, of a diameter less than 100 micron, in virtually transparent samples of trabecular meshwork with a laser delivery system of 6 degrees convergence and pulse energies of 14 mJ or more. The relevance of this and the other experimental results to the development of a reliable system for performing internal trabeculotomies for the treatment of open-angle glaucoma is presented.     

Lysis of vitreous strands with neodymium: YAG laser

Eighteen eyes with vitreous strands adherent to the corneoscleral wounds of previous cataract surgery were treated with neodymium: YAG laser to lyse those strands. Twelve eyes were treated for management of cystoid macular edema (CME group); six eyes were treated for prophylaxis of possible CME (prophylactic group). In the CME group, visual acuity improved two or more lines in nine eyes (75.0%), and seven eyes had a post laser visual acuity of 0.5 or better (One eye had a pre-treatment visual acuity of 0.5 or better). In the prophylactic group, visual acuity was either maintained at the pre-treatment visual acuity of 0.5 or better. In the prophylactic group, visual acuity was either maintained at the pre-treatment level or improved in five eyes (83.3%) 18 months later following laser treatment. This procedure was complicated by retinal detachment in one case and the elevation of intraocular pressure over 10 mmHg in another case.     

Long-term follow-up of neodymium: YAG laser angle surgery for open-angle glaucoma

Seventy-nine eyes (61 patients) with open-angle glaucoma and uncontrolled intraocular pressure (IOP) of 23 mmHg or more despite maximal tolerated medical therapy and prior argon laser trabeculoplasty (75 eyes) were treated with neodymium: YAG (Nd: YAG) laser angle surgery and followed for at least 1 year. Ten pulses of 10 mJ were applied to the midtrabecular meshwork over 40 degrees in the most visible portion of the angle. The IOP was controlled successfully (less than or equal to 22 mmHg) in 60 eyes (76%) 1 month after treatment and in 36 of 78 eyes (46%) 1 year after treatment. Long-term complications included two eyes with advanced glaucoma that lost central fixation despite good IOP control after treatment.     

Complications associated with the use of the neodymium:YAG laser

The neodymium:YAG laser was used in a consecutive series of 93 eyes. Diagnosis was opacified posterior capsule in 81 eyes of which 52 were pseudophakic, with cystoid macular edema and vitreous strands in eight eyes, pigmented anterior hyaloid in two eyes, opacified anterior capsular flap in one eye and vitreous strand blocking an anterior chamber tube shunt to an encircling band tube in one eye. Despite significant visual improvement and reduction of cystoid macular edema, a variety of complications were seen. These included pitting of the implant in 26 eyes and cracks in four, two of which developed a vitreitis. These occurred more frequently in our earlier cases. Also seen was elevated IOP in six eyes, pupillary block in two, vitreous face rupture in five, cystoid macular edema in four, hyphemas in four, corneal injury in two and acute peripheral retinal hemorrhage in one eye.     

Effect of neodymium YAG laser treatment of glaucoma on endothelial cell density of the cornea

In a prospective clinical study corneal endothelium cell density was measured by means of contact specular microscopy prior to and 2, 4 and 12 weeks after Nd-YAG laser treatment. Two different laser techniques were applied: 19 eyes with narrow-angle glaucoma were treated by laser iridotomy, 21 eyes with open-angle glaucoma underwent laser treatment of the trabecular meshwork. The Nd-YAG laser was driven in Q-switched mode (nanosecond range) for iridotomy and in free-running mode (millisecond range) to treat the trabecular meshwork. A mechanical effect (iridotomy) as well as a thermal effect (LTP) of the Nd-YAG laser source was used. The morphometric study of the corneal endothelium revealed a variable increase in cell size, occasional cell loss, and an increase in polymorphism after Nd-YAG laser treatment. The decrease in endothelial cell density was not statistically significant (p = 0.01) for either laser technique. Possible mechanisms and risk factors responsible for endothelial cell loss are discussed.     

Secondary closure of neodymium:YAG laser posterior capsulotomy.

A 67-year-old man reported reduced vision after cataract surgery and neodymium:YAG (Nd:YAG) laser posterior capsulotomy. The diagnosis was complicated due to severe glistenings within the optic of an acrylic foldable intraocular lens (IOL), proliferation of lens epithelial remnants over the capsulotomy opening, and presumed vitreous opacity. Although IOL exchange surgery was considered, a second Nd:YAG laser intervention successfully removed the proliferated lens materials and restored the visual acuity. The glistenings were not the cause of the reduced vision.     

Applications of the neodymium:YAG laser in plastic surgery of the face and lacrimal surgery. Wound repair. A review

The physical and clinical features of a number of laser energy sources presently being used in plastic and endonasal surgery, such as the Nd:YAG, KTP, Ho:YAG, Er:YAG and CO(2) lasers, are emphasized. Particular attention is paid to the Nd:YAG laser and to an Nd:YAG laser-powered quartz laser scalpel.     

The role of 1% sodium hyaluronate in anterior capsulotomy with the neodymium:YAG laser in patients with diseased cornea

Patients with preexisting corneal pathology who needed cataract extraction had an anterior capsulotomy performed with a Q-switched Nd:YAG laser (LASAG Microruptor II). Thirty-two patients had no sodium hyaluronate (Healon) and 36 patients had Healon injected into the anterior chamber prior to the laser surgery. The non-Healon group had a higher incidence of corneal damage from the YAG laser and, as a result, a higher incidence of endothelial corneal decompensation than the patients with the Healon-filled chamber.     

Contact neodymium:YAG laser. Experimental studies and oculoplastic applications

Contact Nd:YAG laser surgery offers a new method of delivering laser energy to a target tissue site. Nd:YAG, a near-infrared laser, can be transmitted through an optical fiber delivery system to a synthetic sapphire probe. This sapphire probe can be used as a surgical scalpel to cut, vaporize, or coagulate tissues. The contact laser scalpel offers many advantages over conventional steel scalpel surgery and the system overcomes many of the limitations encountered with noncontact Nd:YAG lasers. A review of the history, biophysics, and experimental studies is presented. Clinical oculoplastic applications are reviewed.     

Ripple-like intraocular lens damage from a neodymium:YAG laser

We report a case of accidental intraocular lens (IOL) damage during a neodymium:YAG laser capsulotomy. After a single pulse of 0.9 mJ of laser energy, a large area of ripple-like opacity with more than 10 concentric circles surrounding a small hole in a 2.0 diopter IOL was noted. The opacity extended more than one fourth of the IOL diameter and caused a significant visual effect.     

Holmium: YAG and neodymium: YAG laser assisted trans-canalicular dacryocystorhinostomy. Results of 317 first procedures

PURPOSE: To assess the results of the first procedures of trans-canalicular dacryocystorhinostomy according to two different lasers: Neodymium: YAG (Nd: YAG) laser or Holmium: YAG (Ho: YAG) laser. To study the efficiency of two anti-metabolite drugs: mitomycin-C (MMC) and 5 fluoro-uracile (5 FU). To analyse the rate of efficiency of the Ho: YAG laser in the canalicular obstructions. METHODS: Three hundred and seventeen patients were operated: 226 with the Nd: YAG laser, 77 with the Ho: YAG laser and 14 with both lasers; 68 were treated with an application of MMC and 40 patients with an application of 5-FU. Sixty-three patients suffered from a canalicular obstruction. RESULTS: The results are based on 289 procedures 6 months after the operation. The global rate of success was 63.32% after one intervention and 70.24% after one or two revisions. There is no statistically significant difference between Nd: YAG or Ho: YAG lasers. The use of antimetabolites did not improve the success rate. In 65% of the cases the canalicular patency is reached. CONCLUSION: Laser-assisted transcanalicular dacryocystorhinostomy is a very useful method because it does not cause cutaneous scarring and for it has a low rate of morbidity given that it causes very little surgical traumatism. Consequently, it can be used under topical anaesthesia and for patients at risk or suffering from coagulation problems. It can be undertaken in the cases of extremely narrow nasal fossae when an endonasal dacryocystorhinostomy is impossible. This procedure is less successful than external or endonasal dacryocystorhinostomy. The success rate is not modified by the use of antimetabolites or by the type of laser.     

Combined thermal-photodisruptive iridotomy using the argon and neodymium:YAG laser

With the combined thermal-photodisruptive laser technique a large iridotomy of controllable size can be performed without any major complications. Using the Wise 103 diopter contact lens, primary coagulation is performed with short-duration argon laser burns. Subsequently, multiple low-energy single pulses are applied with the Nd:YAG. The iris can thus be perforated step by step. Compared with the pure Nd:YAG laser technique, this procedure reduces the risk of bleeding. Compared with the pure argon laser technique, each iris can be perforated easily, regardless of its color and thickness. The present paper reports on experience gathered in a first group of 50 eyes.