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Cataracts occur when progressive degeneration of the lens of the eye results in loss of lens transparency and blurred, distorted vision. The standard procedure for cataract surgery is extracapsular cataract extraction. This technique leaves the posterior lens capsule intact, thereby reducing the incidence of macular edema (swelling of the area of the retina where central vision takes place), and retinal detachment (separation of the inner nervous tunic from the middle vascular tunic of the eye). The most common complication of cataract surgery is late opacification of the posterior capsule, which occurs following 18 to 50 percent of extracapsular cataract operations. Opacification may be treated by capsulotomy (incision into the posterior capsule) performed using short pulsed Nd:YAG laser. Sight-threatening complications from laser treatment include cystoid macular edema, retinal detachment and glaucoma (elevation of intraocular pressure). A review was undertaken of 897 laser capsulotomies to determine the incidence of these complications. Cystoid macular edema occurred in 11 patients (1.23 percent), and retinal detachment was noted in eight patients (0.89 percent). Glaucoma developed in seven patients (0.78 percent), and worsening of pre-existing glaucoma occurred in five patients (0.56 percent). No risk factors for any of these complications were identified. Complications of retinal detachment and macular edema did not occur for many months after laser treatment, while the interval between these complications and cataract surgery was months to years. These findings indicate that patients who undergo laser capsulotomy should be followed closely for a long period of time, so that if these complications occur they can be identified and treated quickly. (Consumer Summary produced by Reliance Medical Information, Inc.)

Because microplasma formation may provide an energy-absorbing shield that protects the retina from inadvertent injury during neodymium-YAG laser surgery, we studied plasma formation and shielding by three ophthalmic neodymium-YAG lasers (the Q-switched American Medical Optics YAG-100, the mode-locked Meditec OPL-3, and the Q-switched LASAG Sirius Microruptor 2) with three model targets (physiologic saline, 1% sodium hyaluronate, and a cellophane membrane). Plasma formation produced a linear reduction in the transmission of light energy along the beam path in a qualitatively similar manner for all three lasers but there were quantitative differences. Plasma shielding was similar in both saline and sodium hyaluronate; enhancement of the shield effect occurred only with the cellophane membrane target. Operating the lasers at energy levels far above threshold did not reduce total light transmission significantly. Clinical use should be guided by the principle of employing the minimum energy necessary to cut the target tissue.

In three aphakic eyes and two eyes with intraocular lens implants (five patients, four women and one man, ranging in age from 65 to 76 years) persistent shallow or flat anterior chamber was observed despite multiple patent laser or surgical iridectomies. In each case direct application of the neodymium-YAG laser (3 to 11 mJ) to the anterior hyaloid face resulted in immediate deepening of the anterior chamber. This deepening was sustained in four of the cases. These results confirm previous observations suggesting that the anterior hyaloid can be the locus of abnormality in aphakic malignant (ciliovitreal block) glaucoma. Neodymium-YAG “hyaloidotomy” may be better than penetrating surgery in such cases.

We used a Q-switched Nd:YAG laser to create an opening in the internal limiting membrane in three eyes with hemorrhagic detachment of the internal limiting membrane. In all instances, after membranotomy blood was rapidly cleared from the preretinal space resulting in prompt improvement in visual acuity. No retinal injury was observed. Nd:YAG laser photodisruption may be useful in the treatment of some cases of subinternal limiting hemorrhages.

Four members of one family had craniometaphyseal dysplasia. Two of the four had severe optic atrophy with profound loss of vision as a complication of this disorder. Optic nerve decompression attempted in one patient may have caused a reduction in the vision of that eye. Eight years later this patient underwent craniofacial surgery uneventfully for contouring of her facial and cranial bones, but osteotomies and intracranial surgery were specifically avoided because of bony overgrowth in the foramen magnum region.