Passive transfer of anti-HSV-1 IgG protects against stromal keratitis in mice

Cellular immune mechanisms are felt to play a primary role in modulating responses to herpes simplex virus (HSV) infections, but the role of anti-HSV antibody is less clear. We first investigated the effects of passive transfer of murine serum containing anti-HSV antibody and then fractionated IgG subclasses on the development of HSV stromal keratitis in mice. Both immune sera and fractionated IgG's from these sera were effective in preventing stromal keratitis in susceptible mice. Non-IgG immunoglobulins and other serum proteins are unnecessary and inadequate in transferring protection; transfer of sera depleted of IgG had no influence on the development of keratitis. These results suggest an important role for anti-HSV antibody in modulating destructive corneal responses to HSV.

Monoclonal antibodies provide protection against ocular Pseudomonas aeruginosa infection

A panel of well characterized monoclonal antibodies (MAbs) directed against outer membrane proteins H2, or F (porin) of Pseudomonas aeruginosa were examined to determine whether they exhibited any protective effect against subsequent ocular challenge with the bacteria topically applied to the scarified corneal surface. Mice were observed macroscopically following bacterial challenge and the degree of ocular disease graded on a scale of 0 to 4 (0, normal, fully protected cornea; 4, corneal perforation or phthisis, not protected). Mice treated intravenously with either MAb MA1-6 (anti-H2) or MA2-10 (anti-F), or a combination of these two MAbs and MAb MA4-4 (anti-F), two hours before corneal challenge with the viable bacteria, exhibited significantly less corneal disease than mice either not treated with the MAbs, treated with MA4-4 alone or treated with MAb MA1-3 (anti-I). The latter MAb is directed against an outer membrane epitope that is not surface exposed. Light and transmission electron microscopic histopathology also was employed and provided confirmatory evidence to support the macroscopic analyses.

[Use of a rinsing solution for contact lenses in the prevention of amebic keratitis]

Recent reports incriminating Acanthamoeba, a small free-living amoeba, wide-spread in environmental soils and waters, in acanthamoebic keratitis cases wearing soft contact lenses, drew attention to cleaning solutions for contact lenses. The purpose of this report is to discuss the amoebicidal action of a rinsing solution containing 0.001% thimerosal. A. castellanii cysts and trophozoites were incubated with the rinsing solution. Amoeba saline was used as control solution. After 1 h to 96 h of contact time, the survival was studied by growing of trophozoites and excystment of cysts on cultures. The results indicate that trophozoites were destroyed by the rinsing solution after 6 hours, whereas for cysts a negative culture was obtained after 72 h to 96 h. The amoebicidal and cysticidal action of this solution containing mercury corroborates our preceding experience on the effects of mercury derivates on amoebae. The use of amoebicidal solutions in contactology could inhibit and even destroy amoebae on contaminated lenses preventing severe keratitis.

Comparison of the prophylactic effects of 2-deoxycytidine and prednisolone for high-dose intravenous cytarabine-induced keratitis

In a double-masked, randomized fashion, 11 patients with hematologic malignancies received 13 courses of high-dose cytarabine therapy, intravenously (3 g/m2 every 12 hours for five to six days). Each patient received topical prednisolone phosphate 1% in one eye and 2-deoxycytidine 100 microM in the other eye every six hours. Topical therapy was initiated 12 hours before the first cytarabine dose and continued for up to ten days (until four to five days after completion of cytarabine therapy). Slit-lamp biomicroscopy was performed before therapy and then weekly for one month. 2-Deoxycytidine was equally as effective as the topical corticosteroid therapy in reducing photophobia and pain, microcysts, and punctate epithelial erosions, and each treatment gave results significantly better when compared historically to placebo-treated eyes.

Topical vs systemic gentamicin penetration into the human cornea and aqueous humor

Twenty-two patients undergoing penetrating keratoplasty received either topical fortified gentamicin (13.6 mg/mL) or a loading dose of intramuscular gentamicin before surgery. Cornea and aqueous humor samples were obtained and assayed by radioimmunoassay for gentamicin. In the topical group, the average gentamicin levels in the cornea and aqueous were 16.2 micrograms/g and 0.3 microgram/mL, respectively. Parenteral drug levels were less variable and averaged 6.1 micrograms/g in the cornea and 0.4 microgram/mL in the aqueous. Although this study demonstrates that parenteral therapy can be used to deliver adequate drug levels to the cornea, it requires far more antibiotic and subjects the patient to potentially toxic systemic side effects. Therefore, topical administration is the preferred route of delivery of antibiotic to the cornea.

Neuroparalytic keratitis and the effect of cervical sympathectomy following operative procedures for trigeminal neuralgia

A study of 248 patients who underwent operative procedures for trigeminal neuralgia over a nineteen year period is presented, with particular reference to those who developed neuroparalytic keratitis to see if cervical sympathectomy had any protective effect on the cornea. 51 patients underwent cervical sympathectomy, 46 as a prophylactic procedure, and 5 as a treatment for neuroparalytic keratitis. Of these patients 3 (5.9%) developed neuroparalytic keratitis, but 2 of them had had an inadequate sympathectomy. Forty seven patients who did not undergo cervical sympathectomy had either an anaesthetic cornea or a reduced corneal reflex, and of these 11 (23.4%) developed neuroparalytic keratitis. An adequate cervical sympathectomy therefore appears to have a protective effect on the cornea against the development of neuroparalytic keratitis.

Topical prostaglandins inhibit trauma-induced inflammation in the rabbit eye

Topical administration of prostaglandin E1 (PGE1) and prostaglandin F2 alpha (PGF2 alpha) prior to ocular trauma can reduce the ocular inflammatory response in rabbits. In the present study, the ocular trauma consisted of puncture of the cornea, without aspiration of aqueous. Corneal puncture, which causes and inflammatory response, a breakdown of the blood-aqueous barrier, and a biphasic response of the intraocular pressure (IOP), yields a valid model of a mild inflammatory response. Pretreatment with PGE1 and PGF2 alpha led to a lower rise in the aqueous prostaglandin E2 (PGE2) concentration and a reduced inflammatory response after corneal puncture; in addition, the increase in the aqueous protein concentration was smaller and the aqueous ascorbate level was higher. The lower increase in the aqueous PGE2 concentration after pretreatment with PGs correlated with the reduced changes in IOP. It is suggested that PGE1 and PGF2 alpha reduced the trauma-induced inflammatory response by decreasing the formation of endogenous prostaglandins, as reflected by their concentration in aqueous. This study also indicates that the results of studies that require perforation of the cornea or cannulation of the anterior chamber may be affected by profound changes in the levels of cyclo-oxygenase products in the tissues surrounding the aqueous.

Susceptibility of Acanthamoeba to soft contact lens disinfection systems

Members of the genus Acanthamoeba are increasingly recognized as agents of indolent, chronic, infectious keratitis. Recently, Acanthamoeba corneal infection has been reported in some persons who wear soft contact lenses. In this study, three "heat" and three "cold" soft contact lens disinfection systems were tested according to the manufacturers' instructions against Acanthamoeba castellanii and Acanthamoeba polyphaga in separate trials, and with appropriate controls. Suspensions of Acanthamoeba cysts or trophozoites of each species were tested individually. Each of the three heat disinfection units killed all acanthamoebae in one cycle in all trials. A chlorhexidine 0.005%/thimerosal 0.001% solution killed A. castellanii trophozoites and cysts, but those of A. polyphaga survived. Trophozoites and cysts of both species survived an alkyl triethanol ammonium chloride 0.013%/thimerosal 0.002% solution and a hydrogen peroxide 3% preparation. Heat disinfection overall appears to be more effective in killing Acanthamoeba trophozoites and cysts as compared to cold disinfection methods.

Inhibition by phosphoramidon of Pseudomonas aeruginosa elastase injected intracorneally in rabbit eyes

Phosphoramidon (N-(alpha-L-rhamnopyranosyloxyhydroxyphosphinyl)-L-leucyl-L-trypto phan) is a powerful inhibitor of Pseudomonas aeruginosa elastase. The addition of this compound to an elastase solution injected intrastromally in rabbit eyes protected the corneas from the damage of the enzyme for a period of 12 hours. Phosphoramidon is comparable in this respect to the inhibitor 2-mercaptoacetyl-L-phenylalanyl-L-leucine, but is considerably more effective than its analog phosphoryl-L-leucyl-L-phenylalanine (P-Leu-Phe). It is suggested that the rhamnopyranosyl moiety, present in phosphoramidon but not in P-Leu-Phe, is responsible for the difference in the intracorneal activity of the two phosphoramidates. Phosphoramidon as well as the mercaptoacetyl derivative might prove beneficial in the treatment of Pseudomonas aeruginosa corneal infections.

Corticosteroid therapy after anterior radial keratotomy in Primates

Anterior radial keratotomy was performed on nine Green monkey eyes. Four of these eyes received subconjunctival corticosteroid injections immediately after surgery and three times thereafter at three-week intervals. Two eyes received subconjunctival physiologic salt solution injections on the same schedule. Three eyes received no injections after surgery. Although endothelial cell loss in the first week after surgery was reduced in the drug-treated eyes, there were no statistically significant differences in cell densities at nine months after surgery. Corticosteroid therapy after anterior radial keratotomy appeared to confer no long-range benefits in terms of the numbers of corneal endothelial cells in these primate eyes.

Fungal-contaminated soft contact lenses

Examination of clinically seen fungal-contaminated soft contact lenses reveals fungus within the matrix of the lenses in a highly reproductive state. To study the potential hazard of fungal-contaminated soft contact lenses to the cornea, such lenses were placed on abraded corneas of ten rabbits. Sterile lenses were placed on the opposite abraded cornea of each rabbit as a control. Although no fungal keratitis was documented in this experiment, the persistent corneal epithelial disruption seen in seven rabbits, plus the highly reproductive state of the fungus within the lens suggests fungal-contaminated lenses may pose a significant risk to the patient. We recommend prompt replacement of contaminated lenses and instruction of the patient on proper lens hygiene.

Ketoconazole: a new imidazole antifungal agent has both prophylactic potential and therapeutic efficacy in keratomycosis of rabbits

A highly reproducible quantitative model of fungal infection of the rabbit's corneal stromal was produced using multiple corneal microtrephination. Aspergillus flavus (K4/77), at a concentration of 10(6) spores per ml was systematically implanted into the trephine sites in the cornea, and the degree of corneal infection determined. By pre-inoculation and post-inoculation challenge of these cornea with 1% ketoconazole in arachis oil, the prophylactic potential and the therapeutic usefulness of ketoconazole was determined. Ketoconazole, acetyl-dichlorophenyl-imidazole, has a significant prophylactic potential in inhibiting the development of corneal stromal fungal lesions when it is administered to the cornea of New Zealand white male rabbits as a 1% solution in arachis oil for two consecutive times hourly for two hours before the inoculation of the rabbits cornea with an ocular pathogenic Aspergillus flavus. Ketoconazole also has a therapeutic effect in the reduction of well established A. flavus keratitis in rabbits. When administered as 1% solution in arachis oil for ten consecutive hours daily to well established A. flavus lesions of the cornea of New Zealand albino rabbits, ketoconazole took about sixteen days to cure all the corneal lesions. Finally, using a yeast nitrogen base liquid medium, the in vitro minimal inhibitory concentrations of ketoconazole to twenty-five various human ocular pathogenic fungal isolates were determined and used to recommend those fungi for which ketoconazole would be a good choice for therapy.

Topical corticosteroid therapy for corneal toxicity from systemically administered cytarabine

Eleven patients with leukemia refractory to conventional therapy were treated with high doses of cytarabine (3 g/m2 intravenously every 12 hours for six days) followed by daunorubicin (30 mg/m2/day intravenously for three days). Each patient received, in a double-masked, randomized manner, either 1% prednisolone phosphate or placebo eyedrops in each eye 12 hours before and along with the cytarabine so that we could determine whether a topical corticosteroid prevents corneal toxicity from systemic cytarabine. Ten of the 11 patients had a significant reduction in the intensity and duration of the symptoms and signs of corneal toxicity in the corticosteroid-treated eye (P less than .0005). In the placebo-treated eye, pain, photophobia, and tearing occurred at a median time of 6.5 days after initiation of therapy but resolved in approximately one week. Patients receiving high doses of intravenously administered cytarabine should receive topical corticosteroid prophylaxis to reduce the corneal toxicity associated with this treatment.

Factors that influence the efficacy of topical gentamicin prophylaxis for experimental Pseudomonas keratitis

We evaluated the efficacy of topical gentamicin prophylaxis for experimental Pseudomonas keratitis in rabbits by applying gentamicin in concentrations of 0.3 and 4 mg/100 ml, in both solution and ointment vehicles, one or four hours after a superficial stromal scratch was infected topically with Pseudomonas organisms. Under these conditions the most effective prophylaxis was that given early, in solution, and in high concentration.

Intraocular irrigating solutions for pars plana vitrectomy. A prospective, randomized, double-blind study

A prospective, randomized, double-blind study showed that glutathione-bicarbonate-Ringer's solution (BSS Plus) caused significantly less corneal swelling on the first postoperative day after pars plana vitrectomy than did lactated Ringer's solution. By the seventh postoperative day, no difference was seen between the two solutions. We found no correlation between the increase in corneal thickness and either the duration of intraocular irrigation or the volume of solution used or the presence or absence of the lens. No persistent corneal complications were seen.

Use of human fibroblast-derived (beta) interferon in the treatment of epidemic adenovirus keratoconjunctivitis

Topical application of human fibroblast-derived (beta) interferon (HulFN-beta) has been used in treatment of epidemic keratoconjunctivitis due to adenovirus. Patients received a total of 1-2 x 10(5) reference units of HulFN-beta per day, divided into 8-10 drops. Control patients received corticosteroid therapy or a placebo containing human serum albumin, with the same administration schedule. The severity and evolution of symptoms was analyzed according to a number of clinical criterias. The results indicate that in the interferon-treated group the length of the disease was reduced from an average of 27 days to 6.5 days. The number of cases in which keratitis occurred as a complication of the disease was reduced in the interferon-treated group to 10%, as opposed to 57% in the control group. Doses of interferon lower than 5 x 10(4) units per day, were not effective to prevent keratitis.

A critical evaluation of the protection provided by common safety glasses from ultraviolet emissions in welding operations

The purpose of this investigation was to evaluate critically several brands of safety spectacle lens and side shield combinations to determine their attenuation characteristics for ultraviolet (UV) radiation. By combining the information developed in this investigation with field data on UV from arc welding operations, it was possible to draw the conclusion that under the conditions stated, ordinary safety glasses with solid side shields provided adequate eye protection from UV.

A spectacle device to treat facial nerve paralysis

We describe a new method to prevent ocular complications in facial nerve palsy. A device mounted on a spectacle frame senses the blink of the normal eye and closes the lids of the paretic eye by levers which rest on the upper and lower lids. It provides a physiologic replacement of function and prevents corneal exposure.