Pseudodentritic keratitis associated with meibomitis in young healthy males

PURPOSE

To report unusual corneal manifestations of pseudodendritic keratitis in cases of coexisting meibomian gland dysfunction (MGD).

METHODS

Retrospective chart review of five cases of MGD with associated atypical corneal lesions was carried out. Information including patient's age, symptoms and their duration, clinical features, methods of diagnosis, treatment, and outcome were abstracted from the medical records. Pseudodendritic keratitis and MGD was defined before the data collection.

RESULTS

All five patients were males within the age range of 6-24 years. Common symptoms were irritation and watering. MGD, which was defined as stenosis of meibomian gland orifices and/or turbid meibomian secretions, was seen in all the patients. Corneal lesions were epithelial, raised and dendritic in morphology. Blood investigations carried out to rule out tyrosinemia in three of the patients were negative. Bandage contact lens facilitated disappearance of these lesions in five eyes.

CONCLUSIONS

Corneal involvement in the form of pseudodendritic keratitis may be associated with MGD. Application of bandage contact lens facilitated prompt resolution, suggesting mechanical factor with or without other etiological factors may be at interplay in producing these innocuous corneal lesions.

Herpes Simplex Keratitis After Cataract Surgery

PURPOSE

Herpetic keratitis is a rare complication of cataract surgery. We describe 3 cases of herpes simplex keratitis after cataract surgery in eyes with no clinical history of this disease.

METHODS

Three patients underwent uneventful phacoemulsification of cataract with intraocular lens implantation. All were treated postoperatively with topical steroids. On subsequent development of corneal dendritic epithelial lesions in the operated eyes, the corticosteroids were replaced by treatment with topical acyclovir.

RESULTS

The first postoperative day was uneventful. Corneal dendritic epithelial lesions were observed 1-5 weeks postoperatively and healed without sequelae after topical acyclovir treatment.

CONCLUSIONS

In view of the surgical trauma along with the topical corticosteroid treatment commonly prescribed after cataract surgery, physicians should be aware of the possible development of herpetic epithelial keratitis even in patients with no clinical history of this disease.

Unusual dendritic keratitis

Bilateral pseudo-dendritic keratitis in infancy can be due to tyrosinemia, a rare metabolic disorder. Ocular involvement may be the earliest presenting manifestation of this disease. Early diagnosis is essential because dietary modifications can result in complete reversal of the manifestations of this disorder. This disease must be suspected in all cases of non-responsive dendritic keratitis in the pediatric age group, especially if it is associated with cutaneous lesions such as patmoplantar keratosis. Serum tyrosine levels must be done in these cases.

New onset of herpes simplex virus epithelial keratitis after penetrating keratoplasty

PURPOSE

To report a series of patients with no previous history of herpes simplex virus (HSV) infection who had new onset of herpetic keratitis after penetrating keratoplasty (PK).

DESIGN

Noncontrolled, retrospective case series.

METHODS

We included in the study the patients who had new onset of herpetic keratitis after penetrating keratoplasty for corneal diseases unrelated to HSV infection who were seen at the Cornea Service at Wills Eye Hospital (Philadelphia, Pennsylvania) from January 1996 to December 2002. The diagnosis of HSV epithelial keratitis was based on clinical characteristics of either a classic herpetic dendrite, a geographic ulcer, or a nonhealing epithelial defect that responded only to antiviral therapy.

RESULTS

Fourteen patients were included in the study. Eight of these (57%) had presented with a geographic ulcer whereas six patients (43%) had a classic dendrite. The most common primary corneal disease that led to PK was pseudophakic bullous keratopathy (36%), followed by keratoconus (29%), Fuchs dystrophy (21%), and corneal scar unrelated to HSV (14%).

CONCLUSIONS

The ophthalmologist should be aware of the possibility of herpetic keratitis in eyes after PK, even in patients with no previous history of HSV infection.

Acanthamoeba keratitis presenting as dendritic keratitis in a soft contact lens wearer

Acanthamoeba keratitis is a rare cause of corneal infection in Taiwan, which can result in devastating visual outcomes. A 37-year-old woman, who wore soft contact lenses, suffered from severe pain in her left eye. Biomicroscopy revealed dendritic keratitis, radial keratoneuritis, and fine keratic precipitates on her cornea. Culture, using non-nutrient agar plate seeded with Escherichia coli, resulted in heavy growth of Acanthamoeba. The inpatient treatment, including topical neomycin-polymyxin B and metronidazole (0.5%) eyedrops, oral ketoconazole, and then oral prednisolone, successfully controlled the corneal infection. The best-corrected visual acuity was 0.9 without any evidence of recurrence of infection after 21 months of follow up. Acanthamoeba keratitis can present as dendritic keratitis, which mimics herpes simplex infection, thus, delays appropriate treatment. Early diagnosis and judicious treatment are essential for restoring the vision and avoiding the subsequent need of penetrating keratoplasty.

Risk factors for herpes simplex virus epithelial keratitis recurring during treatment of stromal keratitis or iridocyclitis. Herpetic Eye Disease Study Group

AIMS

Possible risk factors were evaluated for herpes simplex virus (HSV) epithelial keratitis in patients with stromal keratouveitis.

METHODS

The study population included 260 patients who had active stromal keratitis and/or iridocyclitis without epithelial disease and who were enrolled in one of three clinical trials of the Herpetic Eye Disease Study. Study treatment involved a 10 week course of topical placebo, topical prednisolone phosphate, or topical prednisolone phosphate with oral acyclovir. All groups received topical trifluridine four times daily for 3 weeks then twice daily for another 7 weeks. Patients were examined for HSV epithelial keratitis for 16 weeks.

RESULTS

Dendritic or geographic epithelial keratitis occurred in 12 (4.6%) study patients. Adverse effects attributable to trifluridine prophylaxis were acute allergic blepharoconjunctivitis in 10 (3.8%) study patients and corneal epithelial erosions in 11 (4.2%) study patients. No significant difference in the occurrence of HSV epithelial keratitis was found among the study treatment groups: one (2.0%) of 49 topical placebo treated patients, nine (6.5%) of 138 patients treated with topical corticosteroids without acyclovir, and two (2.7%) of 73 patients treated with topical corticosteroids and oral acyclovir. Univariate exponential models suggested that patients with a history of previous HSV epithelial keratitis and non-white patients were more likely to develop HSV epithelial keratitis during treatment of stromal keratouveitis.

CONCLUSION

Individuals with prior HSV epithelial keratitis and certain ethnic groups may have a higher rate of recurrent epithelial keratitis during the acute treatment of HSV stromal keratouveitis.

[Vision disorders in inflammatory-rheumatic diseases]

The association of visual disturbances and rheumatic disease has been known for centuries. This review provides a synopsis of the ocular conditions that are associated with inflammatory rheumatic disease. The major ophthalmic manifestations of the rheumatic diseases include keratoconjunctivitis sicca, ulcerative keratitis, scleritis, uveitis, retinal vascular disease, and neuro-ophthalmic lesions. Each of these ocular conditions is most characteristically associated with a few, but not all, of the rheumatic disorders. Scleritis, for example, is most often seen with rheumatoid arthritis or with vasculitis. Acute anterior uveitis is most often seen with the seronegative spondylarthropathies. Retinal vascular and neuro-ophthalmic lesions are seen with disorders having either a vaso-occlusive component, such as systemic lupus erythematosus, or with one of the vasculitides. Important considerations for a successful collaboration between ophthalmologists and physicians/rheumatologists are discussed.

Recurrence rate of herpetic uveitis in patients on long-term oral acyclovir

We examined the recurrence rate of herpetic uveitis (HU) in 13 patients (group A) treated prophylactically with long-term systemic acyclovir (600-800 mg/day) and compared it with that of 7 patients with no prophylactic therapy (group B). HU was diagnosed on the basis of a history of dendritic or disciform keratitis accompanied by iridocyclitis and iris atrophy. The study population consisted of 12 men and 8 women with a mean age at onset of uveitis of 52.9 years (range 19-78 years). All patients were followed for at least 8 months. The mean follow-up time of patients on long-term oral acyclovir was 26.0 months. In this group, only one patient experienced a single recurrent episode of uveitis while on 600-800 mg/day of acyclovir therapy; two additional patients had recurrence of HU within 16.2 months after the acyclovir dose was tapered below 600 mg/day. In striking contrast, 16 recurrences occurred in the 7 patients of group B (p < 0.05). Of these, the initial recurrence occurred within an average of 4.3 months following cessation of therapy. There was a significant difference (p < 0.05) in the mean recurrence-free interval between patients in group A (24.6 months) and those in group B (3.4 months). Herpetic uveitis is a serious ocular disease in which recurrence of inflammation results in severe ocular complications. The long-term use of oral acyclovir may be of benefit in the prevention of recurrences, and hence may reduce the blinding complications of this disease. Efforts at completing a randomized, placebo-controlled trial on this matter by the Herpes Epithelial Disease Study Group were unsuccessful due to insufficient patient recruitment.

[Recurrent herpetic keratitis in mice]

In order to investigate the mechanism of recurrence in herpes simplex keratitis, it is very important to establish an animal model. As a first step, mice were examined with the slit-lamp biomicroscope to determine whether they spontaneously showed recurrent epithelial keratitis after healing of primary herpetic keratitis. Among 90 eyes of 45 inbred C57BL/6 mice, recurrent epithelial keratitis stained with fluorescein was observed in 10 eyes of 9 mice during the observation period up to 50 days after the primary corneal infection with herpes simplex virus (HSV) type I Amakata strain (virulent strain). Recurrent epithelial keratitis was observed in 17 eyes of 15 mice among 116 eyes of 58 ddy mice infected with HSV-I Ska strain (avirulent strain). The epithelial lesions showed punctate or dendritic patterns and continued for one to 7 days. HSV antigen was detected by the fluorescent antibody technique in the cornea of 5 out of 8 eyes which showed recurrent epithelial keratitis using another ddy mice group tested. It was limited in the epithelium of the cornea. These results show that mice herpetic keratitis recurs spontaneously.

Herpes simplex dendritic keratitis after keratoplasty

We treated three patients with herpes simplex dendritic keratitis that occurred between three and 11 months after keratoplasty. The patients had no history of herpetic infection. The eyes of two of the patients were grafted for corneal scarring of undetermined origin. The eye of the third patient was grafted for pseudophakic bullous keratopathy. At the time of onset of dendritic keratitis, all three patients were receiving either maintenance or higher doses of topical corticosteroids. All infections responded to topical antiviral treatment. The findings in these patients illustrate the importance of considering herpes simplex keratitis in the differential diagnosis of all late-onset epithelial defects in the corneal graft, even in the absence of a history of herpes simplex keratitis.

Herpes simplex keratitis in renal transplant patients

Five out of 430 patients (1.16%) undergoing kidney transplantation developed an atypical clinical picture of herpetic dendritic keratitis within four weeks after surgery. It was manifested by multiple dendrites, located mainly in the corneal periphery or the limbus, developing in relatively uninflamed eyes. The response to acyclovir therapy was prolonged and took at least three weeks. Additionally, subepithelial infiltrates with ultimate scarring developed in all patients. Disciform keratopathy was not found. This clinical course is ascribed to the patients' immunosuppressed state.

Ocular ulcerative herpes following measles in Kinshasa, Zaire

Eight cases of ocular ulcerative herpes following measles are reported. The clinical features are characterized by dendritic corneal ulcer (6 cases) and ulcero-erosive blepharitis associated with corneal ulcer (2 cases). Bacteriologic examination disclosed Pseudomonas aeruginosas in 2 cases. The serum level of retinol, RBP, prealbumin and albumin were generally diminished in cases of dendritic corneal ulcer. These data are discussed in relation to the onset and severity of ocular ulcerative herpes associated with measles.

Chronic ocular zoster

In a prospective open trial 40 patients suffering from acute herpes zoster ophthalmicus were treated with systemic acyclovir. An additional 10 patients were treated by topical acyclovir alone and dexamethasone eye-drops were administered to 5 of them to suppress ocular inflammation. In the topical treatment group the period of new skin lesion formation and progression of ocular inflammatory signs were significantly prolonged. Therapy with systemic acyclovir however resulted in a quick and complete resolution of ocular inflammation in all patients. Chronic ocular inflammation developed in 4 out of 10 patients treated with topical acyclovir. We consider chronic ocular zoster as a distinct clinical entity, possibly expressing a failing local immune response against VZV.

The coincidence of HSV-1 ocular cultures with HSV-1 corneal epithelial defects in rabbits after experimental penetrating keratoplasty

Penetrating keratoplasty (PKP) in conjunction with postoperative corticosteroids may reactivate latent herpes simplex virus type 1 (HSV-1) to cause persistent postoperative epithelial defects. The clinical diagnosis of HSV keratitis after penetrating keratoplasty is difficult because the postoperative appearance may be nondendritic and, therefore, not characteristic of HSV-1 infection. Presently, the most reliable method to diagnose HSV-1 under these conditions is to culture eyes for the presence of HSV-1. To determine the coincidence of positive HSV-1 ocular cultures with HSV-1 epithelial defects, 15 rabbits (20 eyes) latently infected with HSV-1 underwent autograft PKP with postoperative corticosteroids. Daily ocular cultures and slit-lamp examinations were performed on postoperative days 1-8 and 10. Viral shedding occurred in 15 of 19 (79.0%) of the eyes postoperatively. Superficial punctate keratopathy (SPK) was observed in 19 of 19 (100%) of the eyes and coincided with positive HSV-1 cultures 24% of the time. Dendritic lesions were observed in three of 19 (15.8%) of the eyes; the dendrites coincided with positive HSV-1 cultures 60% of the time. Finally, epithelial ulcers were seen in eleven of 19 (57.9%) of the eyes, thus coinciding with HSV-1 positive cultures 29% of the time. The greatest coincidence of positive HSV-1 cultures with nondendritic epithelial lesions occurred on postoperative day number 4. The results suggest that an epithelial lesion following PKP and postoperative corticosteroids could represent HSV infection, even if a single HSV ocular culture is negative.

The development of corneal edema in herpes simplex virus type 1-infected rabbits following termination of therapy for corneal stromal disease

One complication of combined antiviral/corticosteroid therapy for herpetic stromal disease in patients is rebound of disease upon termination of therapy. To develop a model of steroid rebound, rabbits were injected intrastromally with 10(3) pfu of HSV-1 (RE strain). Therapy with 1% trifluorothymidine (F3TdR) alone or in combination with immunosuppressive agents was initiated 7 days post-infection, at a time when epithelial disease had reached its peak and corneal thickness had begun to increase. Therapy was continued 5 times daily through day 18 post-infection. Following cessation of therapy 13 of 16 eyes receiving both 1% F3TdR and 0.125% prednisolone acetate experienced rebound of disease characterized by an increase in corneal thickness from 514 +/- 106 microns to 743 +/- 189 microns, reaching a maximum at 27 +/- 3 days post-infection. Rabbits receiving therapy with either phosphate buffered saline or F3TdR alone displayed rebound in 2 and 3 of 12 eyes, respectively. Rabbits receiving F3TdR combined with either cyclosporine or deoxycoformycin experienced rebound of disease in 9 of 20 and 6 of 16 eyes, respectively. Cultures of eye washings taken from eyes at the time of rebound were negative in all cases. The data indicate that only steroids significantly increased the proportion of eyes with rebounding stromal disease and corneal edema. These studies document steroid rebound of stromal disease in an animal model.

Pathogenesis of corneal oedema associated with herpetic eye disease

Corneal oedema and stromal disease, induced in rabbits by intrastromal injection of herpes simplex virus, type 1, strain RE (HSV-1, RE), reached a peak of 12-15 days after infection. Corneal oedema as measured by ultrasonic pachymetry, and stromal disease as measured by a subjective scoring system, were closely related for 30 days after infection. Morphometric analysis of wide field specular micrographs showed that no immediate endothelial cell damage occurred in either control or HSV-1 infected corneas. Alizarin red S staining of corneas taken during the period of most severe oedema indicated no significant endothelial cell loss; however, visual inspection indicated numerous staining abnormalities. Scanning and transmission electron microscopy provided evidence of an intact endothelial layer possessing integrated infiltrating cells. Virus antigen could not be detected on endothelial cells by immunoperoxidase staining at any time during development of corneal oedema. The results indicate that corneal oedema associated with HSV-1 induced disease can occur in the absence of detectable virus replication and cytolysis of corneal endothelial cells.

Treatment of ocular disease in eczema herpeticum

Individuals with atopic dermatitis are particularly susceptible to herpes simplex viral infection and may develop dissemination (eczema herpeticum). Additionally, they may develop severe and bilateral herpetic ocular disease. The keratitis is commonly complicated by stromal scarring and slow epithelial healing despite topical antiviral therapy. We treated three patients who had herpetic keratoconjunctivitis associated with eczema herpeticum. In all three cases the keratitis resolved promptly (48 to 72 hours) without residual scarring after treatment with systemic acyclovir and topical trifluridine. The combined use of systemic acyclovir and topical trifluridine may be of similar value in treating all cases of atopic herpetic keratitis.

Expression of MHC class II antigens and immunoglobulin M by the corneal epithelial cells in herpetic keratitis

The corneal buttons obtained from 4 patients with active epithelial and stromal herpetic keratitis were studied with routine microscopy and immunohistochemistry. We used an immunoperoxidase technique with monoclonal antibodies directed against Langerhans cells, lymphocyte subsets, MHC products and immunoglobulins A, G, M and D. The epithelium and stroma contained an inflammatory infiltrate composed of polymorpho-nuclear leukocytes, dendritic cells, B-lymphocytes and T-lymphocytes (helper/inducer and suppressor/cytotoxic subsets). The epithelial cells of all the corneal buttons expressed MHC class II antigens. IgM was bound to the membrane of the epithelial cells in 3 specimens. HSV antigenic material was localized in the epithelial cells and in the stromal keratocytes by a direct immunofluorescence technique. Our data suggest that cell-mediated as well as antibody-mediated immune responses are involved, with a possible role for an autoimmune mechanism in the pathogenesis of this condition.

[In vitro sensitivity to antiviral agents of herpes simplex viruses isolated from patients with herpetic keratitis]

Thirty-five clinical isolates of herpes simplex virus type 1 (HSV-1) from 34 patients (35 eyes) with herpetic keratitis were examined in vitro for 5-iodo-2'-deoxyuridine (IDU) and acyclovir (ACV) sensitivity. In addition, the effect of clinical treatment with these two drugs in herpetic keratitis was also investigated. The viral effective dose50 (ED50) was defined as the concentration that inhibited the plaque count by 50% compared to the count of the no drug controls. The viral ED50 of IDU ranged from 0.073 to 0.77 micrograms/ml (0.33 +/- 0.16; Mean +/- SD) and that of ACV from 0.0032 to 0.33 micrograms/ml (0.13 +/- 0.11). No virus with markedly diminished sensitivity to IDU and ACV was found. These results suggest that all HSV-1 strains isolated from patients have good sensitivity in vitro to antiviral agents.

Microbial keratitis after penetrating keratoplasty

Thirty cases of microbial keratitis after penetrating keratoplasty were reviewed to examine the associated risk factors, the spectrum of pathogens and the prognosis for graft survival and visual outcome. The indications for keratoplasty in this group differed markedly from those for all corneal grafts performed with a much higher incidence of previous microbial keratitis and of herpes simplex keratitis. A positive culture was obtained in 93% of cases and in contrast to microbial keratitis overall, Gram positive organisms predominated particularly streptococcus pneumoniae and staphylococcus aureus. Risk factors identified were loose or broken sutures, graft decompensation and a poor ocular surface environment. There was a poor prognosis for graft survival with only 23% of cases retaining a clear graft. Overall 53% of cases were regrafted.

Penetrating keratoplasty in rabbits induces latent HSV-1 reactivation when corticosteroids are used

The increased incidence of corneal graft failure in patients with herpes simplex virus (HSV) keratitis may be due in part to reactivation of latent HSV following surgical corneal trauma and postoperative corticosteroid therapy. To determine the onset, frequency, and nature of HSV recurrences following penetrating keratoplasty (PKP), 21 HSV type 1 (HSV-1) latently infected rabbits underwent unilateral autograft PKP. Opposite unoperated eyes served as HSV-1 latently infected controls. Corneal autografts were performed so that immunologic graft rejection would not be confused with recurrent HSV-1 stromal disease. After PKP, 11 of the 21 eyes were treated with dexamethasone. Ocular cultures and slit-lamp examinations were performed daily for the first postoperative 8 days and every other day thereafter for 82 days. Nine (82%) of the 11 dexamethasone-treated PKP eyes, 2 (20%) of the PKP eyes not treated with dexamethasone, and 3 (17%) of the 18 unoperated eyes had positive HSV-1 ocular cultures. Geographic ulcers appeared only in the PKP eyes treated with dexamethasone; 9 (82%) of the 11 PKP eyes treated with dexamethasone developed geographic ulcers. Between the 24th and 90th postoperative days, stromal keratitis appeared in 5 (56%) of the 9 PKP eyes treated with dexamethasone and in 2 (25%) of the 8 PKP eyes not treated with dexamethasone. Autograft PKP with postoperative corticosteroids significantly increased HSV-1 ocular shedding, epithelial ulceration, and stromal keratitis. This experimental model provides a useful tool to further investigate the development and treatment of HSV-1 epithelial and stromal recurrences after PKP.

Oral acyclovir reduces the incidence of recurrent herpes simplex keratitis in rabbits after penetrating keratoplasty

To determine if acyclovir sodium prevents postoperative herpes simplex virus type 1 (HSV-1) recurrences, 21 rabbits harboring latent HSV-1 underwent uniocular autograft penetrating keratoplasty. All operated-on eyes were treated with topical and subconjunctival dexamethasone sodium phosphate. Ten of the 21 rabbits also received oral acyclovir (intravenous acyclovir was given at the time of surgery). Postoperatively, 9 (82%) of 11 operated-on eyes in rabbits not treated with acyclovir had positive HSV-1 ocular cultures. In acyclovir-treated rabbits, however, none of the 10 operated-on eyes had positive ocular cultures. In addition, 9 (82%) of 11 of the operated-on eyes had geographic ulcers develop in the non-acyclovir-treated rabbits, compared with 1 (10%) of 10 in the acyclovir-treated rabbits. Finally, stromal keratitis appeared in 5 (56%) of 9 of the operated-on eyes in non-acyclovir-treated rabbits and 1 (12%) of 8 of the operated-on eyes in acyclovir-treated rabbits. The results of this study indicate that acyclovir significantly lowered the incidence of HSV-1 ocular shedding, geographic ulceration, and stromal keratitis in a rabbit autograft penetrating keratoplasty model.

Exogenous, ocular, and systemic factors associated with keratitic ulceration

Information on type and frequency of empirically observed exogenous, ocular, and systemic predisposing factors for keratitic ulceration is important for clinical identification of groups at risk and may form a basis for planning experimental studies on the pathogenesis of ulceration. Therefore a retrospective study comprising 104 patients with 25 herpetic and 79 non-herpetic corneal ulcerations was performed. Patients with herpetic ulcerations were mainly males and were younger than patients with non-herpetic corneal ulceration. Keratoplasty and steroid treatment was found as frequent co-existing predisposing factors in the herpetic group. In the non-herpetic group an exogenous factor was found in 56%, an ocular factor in 56%, and a systemic predisposing factor in 46% of the patients. In only 2.5% of these patients was there found no predisposing factor. Pathogenetic mechanisms of predisposing factors for non-herpetic corneal ulceration is discussed.

Alterations in the antigenic structure of two major HSV-1 glycoproteins, gC and gB, influence immune regulation and susceptibility to murine herpes keratitis

We previously demonstrated that anterior chamber (AC) injection of HSV-1 before or simultaneous with topical corneal HSV-1 infection resulted in cellular immune tolerance of HSV-1 Ag and a reduced frequency of corneal stromal lesions. In the present study, we have investigated the role of the HSV-1 cell-surface glycoproteins gC and gB in the induction of tolerance, and the resulting reduced susceptibility to HSV-1 corneal stromal disease. These studies utilized mutant strains of HSV-1 with deletion or point mutations in the gene coding for gC or gB. Groups of mice received topical corneal infections with wild-type HSV-1, followed by AC injection of the same eye with wild-type HSV-1 or a mutant strain. Varying the antigenic composition of the virus injected into the AC resulted in three distinct patterns of immune responsiveness. In agreement with our previous findings, AC injection of wild-type HSV-1 induced a state of HSV-1 specific tolerance that extended to both the delayed type hypersensitivity (DTH) and CTL responses. A mutant strain lacking gC (gC-) induced partial tolerance characterized by undetectable CTL activity but a normal DTH response. A mutant strain lacking gB (gB-) caused partial suppression of the CTL response and no reduction of the DTH response. Thus, whereas gB may be involved in CTL tolerance induction in this model, gC clearly is not involved. In contrast, both gC and gB must be present in the AC to induce detectable DTH tolerance. The latter interpretation was strengthened by the observation that AC injection of a mixture of gC- (expressing normal gB) and gB- (expressing normal gC) effectively suppressed the DTH response to wild-type HSV-1. A panel of mar mutants with individual point mutations affecting gC and gB was used to identify the epitopes responsible for induction of DTH tolerance. Two of the gC mutants failed to induce DTH tolerance to wild-type HSV-1 when injected into the AC, suggesting that the sites on the gC molecule that are altered by these mutations are important for the induction of DTH tolerance. Similarly, one of the mar mutants for gB uniformly failed to suppress the DTH response, while another had a variable effect. The unique pattern of cellular immune reactivity exhibited by the mice receiving simultaneous topical corneal infection with wild-type HSV-1 and AC injection of gC- (no CTL but normal DTH) was associated with significantly reduced susceptibility to HSV-1 corneal stromal lesions.(ABSTRACT TRUNCATED AT 400 WORDS)

Ocular herpes simplex infection: pathogenesis and current therapy

Ocular herpes simplex disease has a variable pattern of manifestations and recurrences as a result of the site and extent of the infection, the host immunologic events, the trophic damage within ocular tissues, and the toxic effects of antiviral medications. Laboratory research has established a clinical model and a working hypothesis about the complex pathophysiologic features of the disease and the interaction of the virus with its host tissue. Recent studies have further defined the viral genome and its role in virulence and pathogenicity. Antiviral therapy is effective in some but not all aspects of the ocular infection. A proposed clinical classification of ocular herpes simplex is based on the manifestations associated with viral disease and those associated with the host response and the subsequent structural damage. A plan for medical and surgical management of ocular herpes simplex, based on current knowledge of the disease process, relates to the integrity of the epithelium and the presence of active viral disease.

Bilateral alterations of the ERG and retinal histology following unilateral HSV-1 inoculation

The physiological condition of the retinas of BALB/c mice inoculated unilaterally in the anterior chamber with the KOS strain of herpes simplex virus type 1 (HSV-1) was monitored by ERG recordings. After the ERG recordings, the retinas were examined for histopathological changes. In the inoculated eye, depressed ERGs were recorded on day 2 PI and abolished ERGs on day 4 PI. The changes in the ERGs were complete by day 5-6 PI. Of the 53 inoculated eyes followed for longer than day 6 PI, four (7.5%) remained normal, 30 (56.6%) had reduced ERGs and 19 (35.8%) had abolished ERGs. In the contralateral eyes, the first changes were noted on day 8 PI, and abolished ERGs were recorded on day 9 PI. Of the 55 contralateral eyes followed for longer than 10 days, 15 (27.3%) remained normal, four (7.2%) had reduced ERGs and 36 (65.4%) had abolished ERGs. The percentage of eyes with depressed ERGs was significantly higher in the inoculated than in the uninoculated eyes, and the percentage of eyes with abolished ERGs was significantly higher in the uninoculated eyes than in the inoculated eyes. The histopathological alterations were different for the two eyes. In the inoculated eyes, the changes were mainly in the outer retina, with characteristic folds in the photoreceptor and outer nuclear layer interspersed with normal appearing retina. The pigment epithelium was also abnormal. In the uninoculated eyes, the changes began in the inner retina but rapidly spread to all layers of the retina. This panretinal necrosis accounted for the higher percentage of abolished ERGs in the uninoculated eyes. The differences in the alterations of the ERG and the histopathological changes may be related to the underlying mechanism of action of the HSV-1 during the evolution of the experimental retinopathy.

Immunogenicity versus pathogenicity after anterior chamber inoculation of an acyclovir-induced double mutant of HSV-1

The acyclovir-induced herpes simplex virus Type 1 (HSV-1) strain, R9C2, a double mutant in thymidine kinase (TK) and DNA polymerase (DNA pol), and its parental strain SC16 were compared for their effects on ocular pathology and systemic immunity after unilateral inoculation into the anterior chamber (AC) of BALB/c mouse eyes. Although AC-injected R9C2 produced no retinal necrosis (0/18 eyes), this mutant induced active suppression (33-87%) of anti-HSV delayed type hypersensitivity similar to that induced by another HSV strain, KOS. AC-injected parental strain, SC16, caused fatal disease within 7-10 days, and induced bilateral retinal necrosis and suppression of DTH in 100% of the mice. Preimmunization with R9C2 protected mice in a dose-dependent fashion from the pathologic and lethal effects of AC-injected parental virus. These data suggest that the immunogenicity of the TK and DNA pol double mutant remains intact despite the decreased ocular and systemic pathogenicity observed after intracameral inoculation.

Immunological complications of soft contact lenses

Immunologic reactions may be the basis of some complications associated with the use of soft contact lenses. In the case of giant papillary conjunctivitis, the antigen causing the problem is not known but is presumed to be protein adherent to the lenses. Superior limbic keratoconjunctivitis and dendritic corneal lesions related to soft contact lenses are associated with thimerosal, but occlusive patch tests do not demonstrate consistent delayed hypersensitivity responses to this preservative in these patients, suggesting that a toxic response may be involved. The association of corneal infiltrates and conjunctival hyperemia with delayed hypersensitivity to thimerosal probably represents the strongest immunologic association to date. These patients consistently show delayed hypersensitivity reactions to thimerosal in occlusive patch tests and intradermal tests.

Ocular involvement associated with chronic Epstein-Barr virus disease

Ocular involvement with acute Epstein-Barr virus infection is usually limited to a transient follicular conjunctivitis, although other lesions have been reported. Chronic Epstein-Barr virus infection has recently gained attention, but ocular manifestations have not been emphasized. We describe three patients with chronic infection with prominent ocular involvement. Bilateral uveitis was noted in all patients, ranging from an anterior uveitis that was responsive to steroids to a severe panuveitis with vitritis, cataract, optic disc swelling, and macular edema. In one patient, topical acyclovir ointment resulted in a substantial decrease in the inflammatory reaction when added to systemic acyclovir therapy. Another patient displayed a keratitis that resolved with topical steroid therapy. Cataract and vitreous surgery were also beneficial in the management of these patients.

Recurrent herpes simplex virus type 1 corneal epithelial lesions after radial keratotomy in the rabbit

The effects of radial keratotomy (RK) on herpes simplex virus type 1 ocular shedding and recurrent corneal epithelial lesions were assessed for 14 days after RK in rabbits latently infected with strain McKrae. Ten latently infected rabbits had RK performed on the right eye. The left eye was used as the control. Viral shedding was monitored by ocular tear-film swabs. The recurrent lesions were monitored by slit-lamp examination. In the RK-treated eyes, 15 (11%) of 140 swabs were positive, compared with six (4%) of 140 swabs in control eyes. Slit-lamp examination disclosed recurrent lesions on 18 (33%) of 55 days on which it was performed in the RK group vs three (5%) of 55 days for the control group. The results suggest that patients who have a history of ocular herpes simplex virus type 1 disease are at risk for recurrences after RK.

[Activation of a herpetic infection via corneal transplantation]

Activation of herpes infection in keratoplasty was studied in 26 patients and found to be caused both by operative intervention and the corresponding corticosteroid therapy. The fluorescent antibody technique proved to be the most effective and rapid test for the detection of herpes infection. It is recommended to carry out laboratory control in transplantation of the cornea as well as topical antiviral therapy in the postoperation period not only in patients with herpetic keratitis but also in the subjects operated on for nonspecific leukoma and other diseases of the cornea.

Role of virus-infected mononuclear leukocytes in herpetic chorioretinitis of newborn rabbits

The role of virus-infected mononuclear leukocytes (MNLs) in the pathogenesis of neonatal herpetic chorioretinitis in newborn rabbits was investigated. As early as 2 days after inoculating the animals' skins with type 2 herpes simplex virus (HSV-2), infectious MNLs in the infected animals' peripheral blood were found. The virus was associated, for the most part, with MNLs that belonged to phagocytic and adherent cell fractions. Observations by electron microscopy indicated that HSV-2 was actively replicating in the MNLs. It was also found that as few as 80 virus-infected MNLs injected via the right common carotoid artery were capable of inducing the chorioretinal lesions in 50% of the eyes, but that as many as 10(3) Pfu of free virus were required to produce the same lesions in the same percentage of eyes. This result clearly indicated that virus-infected MNLs were far more efficient in producing chorioretinitis than free virus, and may thus play a crucial role in the pathogenesis of herpetic chorioretinitis in newborn rabbits. When 111In-labeled virus-infected or uninfected MNLs were injected into normal rabbits via the right common carotid artery, the virus-infected MNLs localized more readily in the eye than the uninfected MNLs. The virus-infected MNLs also attached to the cultured vascular endothelial cells significantly more often than the uninfected MNLs. These results suggested that virus-infected MNLs might be easily trapped in the circulation of the eye and, in this way, produce the ocular lesions.

Neonatal herpes simplex virus infections. Presentation and management

Neonatal herpes simplex virus (HSV) infections are recognized to be severe because of their association with significant morbidity and mortality. Through ongoing studies performed by the National Institute of Allergy and Infectious Diseases Collaborative Antiviral Study Group, the presentation, natural history, outcome and value of antiviral chemotherapy have been considered. Infants developing neonatal HSV infections can be classified according to the extent of disease, disseminated or localized. Localized infection can be subdivided into either central nervous system (CNS) disease, occurring in 35% of infected infants, or skin, eye and mouth (SEM) disease, in 41% of infants. Disseminated disease accounts for 24% of neonatal HSV infection. Therapeutic outcome depends upon disease classification. Administration of either 15 or 30 mg/kg/day of vidarabine resulted in significantly decreased mortality for infants with life-threatening disseminated and CNS disease as compared to placebo recipients. Approximately one-third of children developed normally following disseminated disease or CNS infection. When disease was localized to the SEM, no death occurred, and 88% of treated infants developed normally. While these data indicate that therapy is effective for management of infants with neonatal HSV infection, improvements are necessary. Hopefully, a study in progress will demonstrate improved outcome with acyclovir treatment.

[Dendritic keratitis following corneal foreign body]

Traumatogenic herpetic eye disease may be initiated via several pathophysiologic pathways. Trauma of the trigeminal ganglion or adequate systemic alterations are the most effective means of destabilizing ganglionic latency of the herpesvirus with consequent neuronal peripheral virus shedding. Peripheral stimuli seem to have far less effect on ganglionic latency--at least in man. The authors report on a rare case of proven herpetic primary disease. The trigger was probably a small intrastromal foreign body which caused an unusual alteration of the cornea with long-standing healing disorders.

Adrenergic induction of HSV-1 ocular shedding in rabbits

Four groups of latently infected rabbits were induced to shed HSV-1 into the tear film by a one-time ocular iontophoresis of 6-hydroxydopamine (6-HD) followed 3 days later by five consecutive days of twice daily topical epinephrine (Epi). Groups 1 and 4 had both eyes inoculated and Groups 2 and 3 had only one eye inoculated. Groups 1 and 2 had eyes swabbed to detect HSV-1, and Groups 3 and 4 had eyes washed. Group 1 was iontophoresed with 1.0% 6-HD at 0.5 mAmp for 5 min, and Groups 2, 3 and 4 were iontophoresed with 0.1% 6-HD at 0.75 mAmp for 5 min. Group 1 received topical 2.0% Epi, and Groups 2, 3, and 4 received topical 1.0% Epi. Inoculated eyes in all groups shed HSV-1 during the induction period. The peak of HSV-1 shedding occurred on the last day of Epi application for Groups 1 and 2, and on the day after the last Epi application for Groups 3 and 4. The ratio of total positive tear film samples to total samples for inoculated eyes that received 6-HD and Epi were 53/119 (45%), 38/87 (44%), 24/66 (36%), and 14/33 (42%) for Groups 1, 2, 3, and 4, respectively. Therefore, even reduced concentrations of 6-HD and Epi, as well as beginning Epi 3 days after 6-HD, induced HSV-1 ocular shedding.

[Development and practical use of new experimental models of the various forms of herpetic infection]

New experimental models of neurological herpes in cotton rats and genital herpes in male guinea pigs have been developed which are more adequate to the corresponding human diseases, and models of ophthalmic herpes in rabbits and guinea pigs have been improved. These models may be used for screening and evaluation of the effectiveness of drugs for herpes. A high activity against herpes of bromovinyldeoxyuridine and acyclovir has been verified, a marked therapeutic effect of Soviet monophosphates ara-A, ara-C, and original silur preparation in some forms of herpes infection has been demonstrated.

An animal model of ocular herpes. Keratitis, retinitis and cataract in the mouse

Acute ocular infection followed both intracerebral and intranasal inoculation of herpes simplex type I virus (HSVI) in mice. Eye infections were a terminal complication of fatal encephalitis. After intracerebral inoculation HSVI spread directly along the optic nerves to infect the retina provoking a necrotizing retinitis. In contrast after intranasal inoculation, HSVI spread via the fifth cranial nerve to the anterior chamber of the eye producing keratitis and uveitis. Necrotizing retinitis was also produced by intracerebral inoculation of mice with a drug-resistant mutant HSVI known to have relatively low neurovirulence. These animals developed only mild encephalitis but this was associated with florid retinitis. The mice survived cerebral infection with the mutant virus and several weeks after initial inoculation cataracts were observed. There was no evidence, at any time, of virus infection of lens epithelium and cataracts appeared to be a non-specific consequence of retinal injury. It is suggested that these examples of murine ocular infection provide animal models for herpetic eye lesions in man and thus may elucidate the pathogenesis of herpetic keratitis, retinitis and cataract.

Microbial factors in contact lens fitting

As contact lens practitioners, optometrists work in a nonsterile environment and on a nonsterile part of the human body. Our report describes 10 cases of eye infection related to contact lens wear. Practitioners need to be aware of the problems which can occur when a thoroughly sterilized contact lens is placed on an unsterile and biologically complex eye. We recommend taking swabs of the conjuctiva in all eyes where ocular inflammation is present. In those areas in which the professions of optometry and medicine meet, cooperation should exist. Improving our knowledge and skills in microbiology helps to facilitate such cooperation. Our experience has been most rewarding and interaction in this field with medical practitioners has been positive. The use of a high quality slitlamp is essential.

Ocular complications of atopic dermatitis

Atopic dermatitis is a common skin disease associated with other allergic diatheses. Ocular complications were seen in 85 (42.5%) of 200 patients. Blepharoconjunctivitis, cataracts, corneal disease and ocular herpes simplex were frequent. Cataract surgery was usually successful, but there were complications of such surgery. The rate of success in attempts to wear contact lenses was surprisingly high for both phakic and aphakic patients.