Calvarial, orbital and dural vascular anomalies in hereditary hemorrhagic telangiectasia.

Hereditary hemorrhagic telangiectasia is an autosomal inherited defect. Associated neurological abnormalities may occur. A case is reported with cutaneous and visceral lesions associated with calvarial, dural and orbital vascular malformations. Striking radiological abnormalities were present.

Combined trabeculectomy and cataract extraction. Advantages of a modified technique and review of current literature.

The management of eyes with both cataract and glaucoma is reviewed. An argument is made for the use of combined cataract and glaucoma surgery as the initial procedure in eyes that have glaucoma, regardless of preoperative control, with cataract which requires removal. The combined operation is also recommended in eyes that require glaucoma surgery and have significant cataract (i.e. visual acuity of 6/12 or reading 6 pt print). A comparison of the results of a modified combined procedure with those of an initial cataract or glaucoma procedure followed by a second procedure at a later date and with those of previous combined procedures demonstrates the advantages of the former. The combined trabeculectomy and cataract extraction is modified by the use of a fornix-based conjunctival flap and by tightly suturing the lamellar trabeculectomy scleral flap to its base. The advantage of this technique is that a 3 1/2-year follow-up demonstrates a lower risk of postoperative complications compared with combined trabeculectomy with a loosely-sutured or unsutured scleral flap which has the same risk of postoperative complications, including shallow or flat anterior chamber, as do combined classical filtering procedures (thermal sclerostomy, trephination, sclerectomy, iridencleisis). We have reviewed 46 eyes operated by this technique and followed them for an average of 3 1/2 years. In 44 eyes the postoperative intraocular pressure is well controlled and the visual fields remain stable.

The role of laser sclerostomy in glaucoma surgery.

With the recent propagation of laser systems for the treatment of glaucoma, we logically seek to understand the rationale for the application of laser energy to glaucoma filtering procedures. If lasers can provide a better means of controlling open-angle glaucoma than is currently available by the use of medications, topically or orally, or by the currently employed surgical methods, we must then ask-which lasers and techniques are currently employed to utilize this technology? In particular what is the role of laser sclerostomy in treating glaucoma? What are the advantages and disadvantages of the various lasers, procedures, and techniques for treating glaucoma? What information does it provide us for future applications of laser surgery in glaucoma? This article addresses these issues.

Stress wave amplitudes during laser surgery of the cornea.

PURPOSE: To determine the stress wave amplitudes generated during photoablation of the cornea using an argon fluoride excimer laser. DESIGN: Experimental study using porcine eyes. METHODS: Profiles of the stress wave amplitudes and enucleated human eyes along the axis of symmetry of porcine eyes and enucleated human eyes were measured using a miniature piezoelectric transducer. The ablation parameters, fluence, and ablation diameters were varied within the range of clinical application. MAIN OUTCOME MEASURES: Stress wave amplitudes generated during photoablation. RESULTS: The stress waves pass through a pressure focus located in the posterior lens and anterior vitreous, where amplitudes of up to 100 atm were measured with a 6-mm or larger ablation zone. Posterior to this focus, the stress wave amplitudes rapidly decrease to less than 10 atm at the retinal site. Small diameter excimer laser spots (< or =1.5 mm) produce a declining stress wave with no pressure focus at the lens and anterior vitreous. CONCLUSIONS: Stress waves may be potentially hazardous to anterior structures of the human eye, including the corneal endothelium, lens and anterior vitreous face. They peak at the lens and vitreous with a broad beam, but not with small spot laser ablation. At posterior retinal and subretinal structures, they may be considered harmless.

Aphidicolin resistance in herpes simplex virus type I reveals features of the DNA polymerase dNTP binding site.

We describe the mapping and sequencing of mutations within the DNA polymerase gene of herpes simplex virus type 1 which confer resistance to aphidicolin, a DNA polymerase inhibitor. The mutations occur near two regions which are highly conserved among DNA polymerases related to the herpes simplex enzyme. They also occur near other herpes simplex mutations which affect the interactions between the polymerase and deoxyribonucleoside triphosphate substrates. Consequently, we argue in favor of the idea that the aphidicolin binding site overlaps the substrate binding site and that the near-by conserved regions are functionally required for substrate binding. Our mutants also exhibit abnormal sensitivity to another DNA polymerase inhibitor, phosphonoacetic acid. This drug is thought to bind as an analogue of pyrophosphate. A second-site mutation which suppresses the hypersensitivity of one mutant to phosphonoacetic acid (but not its aphidicolin resistance) is described. This second mutation may represent a new class of mutations, which specifically affects pyrophosphate, but not substrate, binding.

Results of excimer laser photorefractive keratectomy for the correction of myopia.

PURPOSE: This report summarizes the authors' 3-year experience with excimer laser photorefractive keratectomy on 240 eyes of 161 patients. METHODS: With constant laser emission parameters, nitrogen flow across the cornea was used on 79 eyes, whereas 161 eyes had no nitrogen flow. Of the 240 eyes, 74 were operated on without suction ring fixation. Postoperative pain management included patching and oral analgesics in 77 eyes and the use of topical diclofenac or ketorolac and a therapeutic soft contact lens in 163 eyes. Follow-up ranged from 1 month (206 eyes) to 36 months (10 eyes). RESULTS: At 3 months, 88% (144 eyes) had uncorrected visual acuity of 20/40 or better; 86% (151 eyes) had corrected visual acuity to within +/- 1 diopter of intended correction, and 10% (17 eyes) lost two or more lines of best-corrected visual acuity. At 12 months, 89% (122 eyes) achieved uncorrected visual acuity of 20/40 or better, 79% (115 eyes) had corrected visual acuity to within +/- 1 diopter of intended correction, and 4% (6 eyes) lost two or more lines of best-corrected visual acuity. At 24 months, 92% (44 of 48 eyes) had uncorrected visual acuity of 20/40 or better, 86% (44 of 51 eyes) had corrected visual acuity to within +/- 1 diopter of intended correction, and 5% (2 eyes) lost two or more lines of best-corrected visual acuity. At 36 months, 90% (9 eyes) achieved an uncorrected visual acuity of 20/40 or better, 90% (9 eyes) had corrected visual acuity to within +/- 1 diopter of intended correction, and no eyes lost two or more lines of best-corrected visual acuity. CONCLUSIONS: The results obtained with one procedure are within accepted standards of accuracy for refractive surgery, and there is the potential for refinement of the final optical correction. Complication rates are low and are not vision threatening. They included increased intraocular pressure, epithelial "map dot" changes, and recurrent corneal erosion syndrome, "central islands," and others. Photorefractive keratectomy appears to be a safe procedure over the short and medium term.