Immobilization of viral antigens on filter paper for a [125I]staphylococcal protein A immunoassay: a rapid and sensitive technique for detection of herpes simplex virus antigens and antiviral antibodies.

A new technique is described for the rapid detection and quantitation of herpes simplex virus (HSV) antigens and antiviral antibodies. It involves immobilization of HSV antigens on filter paper discs and subsequent analysis by 125I-labeled staphylococcal protein A (SPA) radioimmunoassay. A specially designed 96-well filtration device is employed which serves both as an incubation chamber and as a filtration manifold. It is rapid, simple, sensitive and specific, and requires only small volumes of antiserum and few target cells. The results may be readily and objectively quantitated. This technique permits the simultaneous assay of a large number of specimens in less than 1 h. Its sensitivity is considerably greater than that of other currently used immunologic techniques, and it is amenable to automation. These characteristics suggest that this [125I]SPA immunofiltration technique may be applicable to the rapid diagnosis of viral infections.

Fibronectin production by cultured human trabecular meshwork cells.

Postmortem explants of human trabecular meshwork from 23 eyebank eyes had a growth rate of 32% (71/160) cultures, with 8% (12) showing abundant cellular spread. One hundred percent confluency was achieved with eyes from donors of 11 to 40 years of age. One of the cultures grew profusely and we were able to study it through eight passages in culture. This culture had the morphologic characteristics described by Polansky et al. for cultured human trabecular meshwork cells. A sensitive radioimmunoassay for fibronectin in tissue culture supernatant showed an increase in fibronectin secretion over a 96 hr period, with a characteristic shift-down response occurring between 24 and 48 hr postmedia change. Three of four cultures showed the presence of laminin, a basement membrane protein, establishing that the cells are not fibroblasts.

Fibronectin in human trabecular drainage channels.

Fibronectin, an extracellular glycoprotein, has been shown to be produced by human trabecular cells in culture by our group as well as Polansky and co-investigators. Studies of Rodrigues et al suggested that fibronectin may be one of several glycoproteins found in increased amounts in the corneoscleral trabecular meshwork of glaucomatous eyes. The authors have developed a sensitive immunoassay utilizing avidin-biotinylated enzyme complex (ABC) to detect low levels of fibronectin in frozen sections of human eyes. The authors have used this immunoassay together with a perfusion technique to demonstrate distribution patterns of fibronectin present in human aqueous drainage channels. The authors found that fibronectin is present in larger quantities in the aqueous drainage channels than in the surrounding tissues in 18 eyes from older patients.

Selective binding affinity of human plasma fibronectin for the collagens I-IV.

The binding of plasma fibronectin to the collagens I, II, and III was greater in a cohort of glaucoma patients. In contrast, binding of plasma fibronectin to collagen type IV was less in 39 glaucoma patients than in any of 3 other diagnostic categories, including 92 patients that were normal, cataract, and glaucoma suspect patients. This observation may have significance in further understanding the control of aqueous outflow resistance in glaucoma and nonglaucoma patients.

A continuous-wear hydrophilic lens. Prophylactic topical antibiotics.

Seventeen patients, who were fitted with a continuous-wear hydrophilic lens for 12 weeks, received topical neomycin sulfate-polymyxin B sulfate-gramicidin (Neosporin) eyedrops in one eye only at a frequency of 3.7 times per day. The continuous wear of a hydrophilic lens in and of itself did not after normal bacterial flora, and the use of the antibiotic drops did not alter normal conjunctival flora. In addition, the eyedrops were not more effective when used in conjunction with the hydrophilic lens and did not appear to produce resistant organisms during the 12-week study. In normal eyes, a continuously worn hydrophilic soft contact lens that is well tolerated does not adversely affect the bacterial flora and the addition of neomycin sulfate-polymixin B-gramicidin drops at a frequency of 3.7 times per day does not appear to be beneficial or necessary.

Economic aspects of the management of ocular hypertension.

Ocular hypertension is a statistical concept, but its presence should arouse suspicion of glaucoma. Glaucoma is an optic neuropathy. Screening for ocular hypertension may not be economically sound because of the high false positive detection rate. Glaucoma is without cost until it is treated or too late. If treatment prevents visual loss it is worthwhile. However, treatment may not prevent glaucoma-induced visual loss. It could be argued that it is more economical to ignore glaucoma than to either screen for ocular hypertension or treat glaucoma. Ophthalmologists will continue to disregard these points, partly because they don't believe them or are fearful of liability, but more likely because they are more concerned about an individual person than about statistical proof of benefit and their primary goal is to avoid risk to the patient even if this is not clearly cost-effective. That decision is correct until better techniques are developed for predicting visual field loss and more effective therapies are established to prevent visual field loss.

Patient compliance and the "usefulness product" of timolol.

The practical value of any therapy depends upon a combination of effectiveness of the agent (or procedure) and the extent to which the patient complies in its proper administration. Thus, it might be said that the multiple of effectiveness times compliance equals the "usefulness product." Among the various glaucoma therapies, this product seems to range from about 30%--90%. Timolol's effectiveness in lowering intraocular pressure combined with its low incidence of side effects yields a high usefulness product, and this may decrease the incidence of surgery required for the treatment of the open-angle glaucomas.

What can we learn from the visual care system of the British National Health Service?

The development of the British National Health Service over the past three decades is described, with particular emphasis on delivery of eye care. Differences between the British and American systems are discussed with consideration of the general political, philosophical and socioeconomic conditions of both countries.

Clinical evaluation of continuous-wear hydrophilic lenses.

Twenty patients who had previously not worn contact lenses were fitted with a thin, continuous-wear hydrophilic contact lens in the right eye for 12 weeks. Seventeen patients completed the study and tolerated the lenses well. Some patients developed changes in corneal thickness, corneal curvature, and refraction, and some changes in visual acuity were reversed when the lens was removed. Many developed lens opacities that did not interfere with vision. We encountered no infections or corneal neovascularization in this study.

Corneal endothelial damage associated with phacoemulsification.

Twenty-one cats underwent standard Kelman phacoemulsification procedures in their right eyes. The left eyes of the same amimals underwent a planned extracapsular cataract extraction or irrigation and aspiration for 15 minutes using the Kelman phacoemulsification unit. The corneal endothelium was evaluated at various times postoperatively using a stain for endothelial cell viability and scanning electron microscopy. The results suggested that the irrigation procedure alone is deleterious to the cat endothelium as is the rubbing of nuclear material against the endothelial cells. These two procedures caused additonal damage when combined in a routine phacoemulsification procedure.

Trends in cataract surgery and intraocular lenses in the United States.

Cataracts are the second leading cause of blindness in the United States. The rate of cataract surgery has greatly increased in the past several years, in part because of the extensive use of intraocular lenses for aphakic correction. It is estimated that more than 600,000 cataract operations were done in 1982. During a similar period, an estimated 496,000 intraocular lenses were implanted. Thus, more than 70% of all cataract operations in the United States involved intraocular lens implantation. Although iris fixation lenses accounted for 52% of all intraocular lenses implanted in 1978, during the six-month period from July 1982 through January 1983 57% of all implanted intraocular lenses were posterior chamber lenses and 40% were anterior chamber lenses.