Current perspectives on ophthalmic mycoses

Fungi may infect the cornea, orbit and other ocular structures. Species of Fusarium, Aspergillus, Candida, dematiaceous fungi, and Scedosporium predominate. Diagnosis is aided by recognition of typical clinical features and by direct microscopic detection of fungi in scrapes, biopsy specimens, and other samples. Culture confirms the diagnosis. Histopathological, immunohistochemical, or DNA-based tests may also be needed. Pathogenesis involves agent (invasiveness, toxigenicity) and host factors. Specific antifungal therapy is instituted as soon as the diagnosis is made. Amphotericin B by various routes is the mainstay of treatment for life-threatening and severe ophthalmic mycoses. Topical natamycin is usually the first choice for filamentous fungal keratitis, and topical amphotericin B is the first choice for yeast keratitis. Increasingly, the triazoles itraconazole and fluconazole are being evaluated as therapeutic options in ophthalmic mycoses. Medical therapy alone does not usually suffice for invasive fungal orbital infections, scleritis, and keratitis due to Fusarium spp., Lasiodiplodia theobromae, and Pythium insidiosum. Surgical debridement is essential in orbital infections, while various surgical procedures may be required for other infections not responding to medical therapy. Corticosteroids are contraindicated in most ophthalmic mycoses; therefore, other methods are being sought to control inflammatory tissue damage. Fungal infections following ophthalmic surgical procedures, in patients with AIDS, and due to use of various ocular biomaterials are unique subsets of ophthalmic mycoses. Future research needs to focus on the development of rapid, species-specific diagnostic aids, broad-spectrum fungicidal compounds that are active by various routes, and therapeutic modalities which curtail the harmful effects of fungus- and host tissue-derived factors.

The mycotic ulcer treatment trial: a randomized trial comparing natamycin vs voriconazole

OBJECTIVE

To compare topical natamycin vs voriconazole in the treatment of filamentous fungal keratitis.

METHODS

This phase 3, double-masked, multicenter trial was designed to randomize 368 patients to voriconazole (1%) or natamycin (5%), applied topically every hour while awake until reepithelialization, then 4 times daily for at least 3 weeks. Eligibility included smear-positive filamentous fungal ulcer and visual acuity of 20/40 to 20/400.

MAIN OUTCOME MEASURES

The primary outcome was best spectacle-corrected visual acuity at 3 months; secondary outcomes included corneal perforation and/or therapeutic penetrating keratoplasty.

RESULTS

A total of 940 patients were screened and 323 were enrolled. Causative organisms included Fusarium (128 patients [40%]), Aspergillus (54 patients [17%]), and other filamentous fungi (141 patients [43%]). Natamycintreated cases had significantly better 3-month best spectacle-corrected visual acuity than voriconazole-treated cases (regression coefficient=0.18 logMAR; 95% CI, 0.30 to 0.05; P=.006). Natamycin-treated cases were less likely to have perforation or require therapeutic penetrating keratoplasty (odds ratio=0.42; 95% CI, 0.22 to 0.80; P=.009). Fusarium cases fared better with natamycin than with voriconazole (regression coefficient=0.41 logMAR; 95% CI,0.61 to 0.20; P<.001; odds ratio for perforation=0.06; 95% CI, 0.01 to 0.28; P<.001), while non-Fusarium cases fared similarly (regression coefficient=0.02 logMAR; 95% CI, 0.17 to 0.13; P=.81; odds ratio for perforation=1.08; 95% CI, 0.48 to 2.43; P=.86).

CONCLUSIONS

Natamycin treatment was associated with significantly better clinical and microbiological outcomes than voriconazole treatment for smear-positive filamentous fungal keratitis, with much of the difference attributable to improved results in Fusarium cases.

APPLICATION TO CLINICAL PRACTICE

Voriconazole should not be used as monotherapy in filamentous keratitis.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00996736

Experimental keratomycosis in a mouse model

PURPOSE

To establish a murine model of corneal candidiasis that permits molecular evaluation of fungal adherence and invasion.

METHODS

Corneas of immunocompetent, methylprednisolone-treated, and cyclophosphamide-treated adult NIH Swiss and BALB/c mice were topically mock inoculated or inoculated with 10-fold increasing amounts between 100 and 100 million colony-forming units (CFU) of Candida albicans after unilateral corneal scarification. Mock-inoculated eyes served as the control. Eyes were scored daily on a 12-point scale to categorize corneal inflammation and were enucleated for quantitative fungal cultures, analysis by polymerase chain reaction (PCR), and histopathologic examination.

RESULTS

At least 100 CFU of C. albicans initiated measurable corneal infection, but 1 million or more colony-forming units were needed to induce consistent keratitis. Treatment with methylprednisolone increased disease severity in infected BALB/c mice and fungal persistence in both BALB/c and NIH Swiss mice. Treatment with cyclophosphamide increased disease severity and fungal persistence in both strains of mice. Infectious organisms were recovered by quantitative culture, and candidal DNA was detectable by PCR. C. albicans, inflammatory cells, and stromal necrosis were histologically evident within ocular tissue.

CONCLUSIONS

Although mice are innately resistant to Candida infection after corneal inoculation, moderate to severe keratomycosis can be established in immunocompromised mice by the route of corneal scarification. Although differences between mouse strains and among immunosuppressive regimens remain to be explored, this murine model provides the basis for understanding the pathogenesis of fungal infections of the cornea.

Endophthalmitis after penetrating trauma. Risk factors and visual acuity outcomes

PURPOSE

To identify clinical characteristics that were associated with an increased incidence of endophthalmitis in eyes with penetrating ocular trauma.

METHODS

In part 1, a retrospective analysis was performed on 258 consecutive patients with penetrating ocular trauma presenting to the Bascom Palmer Eye Institute between October 1987 and January 1991. In part 2 of the study, 28 consecutive patients with culture-proven endophthalmitis were identified from the Clinical Microbiology Registry from April 1987 through September 1987 and February 1991 through August 1993. Clinical variables were evaluated in each part for association with an increased risk of endophthalmitis.

RESULTS

In part 1 of the study, endophthalmitis developed in 13 (5%) of the 258 patients. Endophthalmitis did not occur in eyes that had blunt injury. In those eyes with a lacerating injury, there was an increased relative risk of infection in eyes with disruption of the crystalline lens. This risk factor was found statistically significant by univariate and multivariate analysis. In part 2 of the study, lens disruption was present in 24 (86%) of 28 patients with culture-proven endophthalmitis. Of the 41 patients with infection from part I and part II, 22 (54%) achieved visual acuity of 20/ 400 or greater. Endophthalmitis caused by coagulase-negative staphylococci had the best visual outcome, with 7 (64%) of 11 patients obtaining visual acuity of 20/ 400 or greater.

CONCLUSION

Lens disruption in eyes with penetrating trauma is a significant risk factor for the development of endophthalmitis. The prognosis for useful vision in eyes with posttraumatic endophthalmitis is best when infection is caused by less virulent organisms.

Fungal and parasitic infections of the eye

The unique structure of the human eye as well as exposure of the eye directly to the environment renders it vulnerable to a number of uncommon infectious diseases caused by fungi and parasites. Host defenses directed against these microorganisms, once anatomical barriers are breached, are often insufficient to prevent loss of vision. Therefore, the timely identification and treatment of the involved microorganisms are paramount. The anatomy of the eye and its surrounding structures is presented with an emphasis upon the association of the anatomy with specific infection of fungi and parasites. For example, filamentous fungal infections of the eye are usually due to penetrating trauma by objects contaminated by vegetable matter of the cornea or globe or, by extension, of infection from adjacent paranasal sinuses. Fungal endophthalmitis and chorioretinitis, on the other hand, are usually the result of antecedent fungemia seeding the ocular tissue. Candida spp. are the most common cause of endogenous endophthalmitis, although initial infection with the dimorphic fungi may lead to infection and scarring of the chorioretina. Contact lens wear is associated with keratitis caused by yeasts, filamentous fungi, and Acanthamoebae spp. Most parasitic infections of the eye, however, arise following bloodborne carriage of the microorganism to the eye or adjacent structures.

Endogenous Aspergillus endophthalmitis. Clinical features and treatment outcomes

OBJECTIVE

This study evaluated the clinical features and treatment outcomes in patients with endogenous Aspergillus endophthalmitis.

DESIGN

The study design was a multicenter retrospective chart review.

PARTICIPANTS

Ten patients (12 eyes) with culture-proven endogenous Aspergillus endophthalmitis treated by 1 of the authors were studied.

INTERVENTION

Intravitreous amphotericin B injection, pars plana vitrectomy, systemic amphotericin B therapy, and oral anti-fungal therapy were performed.

MAIN OUTCOME MEASURES

Elimination of endogenous Aspergillus endophthalmitis and Snellen visual acuity, best corrected, were measured.

RESULTS

All patients had a 1- to 3-day history of pain and marked loss of visual acuity in the involved eyes. Varying degrees of vitritis was present in all 12 eyes. In 8 of 12 eyes, a central macular chorioretinal inflammatory lesion was present. Four patients (six eyes) had associated pulmonary diseases and were receiving concurrent steroid therapy. One of these patients with chronic asthma also was abusing intravenous drugs. Overall, six patients (six eyes) had a history of intravenous drug abuse, whereas a seventh patient (one eye) was suspected of abusing intravenous drugs. Blood cultures and echocardiograms were negative for systemic aspergillosis. Management consisted of a pars plana vitrectomy in 10 of 12 eyes. Intravitreous amphotericin B was administered in 11 of 12 eyes. Systemic amphotericin B therapy was used in eight patients. One patient was treated with oral antifungal agents. In three eyes without central macular involvement, final visual acuities were 20/25 to 20/200. In eight eyes with initial central macular involvement, final visual acuities were 20/400 in three eyes and 5/200 or less in four eyes. Two painful eyes with marked inflammation, hypotony, and retinal detachment were enucleated.

CONCLUSIONS

Endogenous Aspergillus endophthalmitis usually has an acute onset of intraocular inflammation and often has a characteristic chorioretinal lesion located in the macula. Although treatment with pars plana vitrectomy and intravitreous amphotericin B is capable of eliminating the ocular infection, the visual outcome generally is poor, especially when there is direct macular involvement.

Infectious keratitis

PURPOSE OF REVIEW

Infectious keratitis is a medical emergency. Improper management can lead to marked loss of vision. This review identifies recent trends in the study of infectious keratitis.

RECENT FINDINGS

A multicountry outbreak of Fusarium keratitis emphasizes that contact lens wear is a major risk factor for infectious keratitis. Acanthamoeba and fungal keratitis are the most expensive forms of infectious keratitis to treat. Noninvasive methods and molecular techniques have improved diagnosis of infectious keratitis. Fortified topical antibiotics and fluoroquinolones are still the mainstay of bacterial keratitis therapy. Voriconazole and new routes of administration of conventional antifungals appear promising for fungal keratitis. Antivirals and amelioration of host inflammatory response are promising for viral keratitis; the host response is also crucial in pathogenesis of Pseudomonas aeruginosa keratitis. Trauma-induced bacterial and fungal keratitis and contact lens-associated keratitis are preventable entities.

SUMMARY

Improved modalities of diagnosis and treatment have improved the outcome of infectious keratitis, but therapy of acanthamoebal, fungal and P. aeruginosa keratitis is still a challenge. Effective strategies must neutralize potential risk factors and counter host response overactivity without impairing killing of infecting microorganisms. Trauma-induced bacterial and fungal keratitis can be prevented.

Endophthalmitis associated with microbial keratitis

PURPOSE

The purpose of the study is to investigate possible risk factors, organisms cultured, and visual acuity outcomes of endophthalmitis associated with microbial keratitis.

METHODS

Records were reviewed of all patients with both positive corneal and positive intraocular cultures at the Bascom Palmer Eye Institute between January 1, 1990, and March 31, 1995.

RESULTS

Thirteen (92.9%) of 14 patients identified had documented keratitis before the diagnosis of endophthalmitis was made. Thirteen (92.9%) patients recently had used 1% prednisolone acetate eye drops, 2 (14.3%) received oral prednisone, and 5 (35.7%) were being treated for systemic conditions associated with relative immune dysfunction. Eight (57.1%) patients had a history of ocular surgery, and seven (50.0%) had wound abnormalities. Eight (57.1%) patients lacked an intact posterior capsule, four (28.6%) had a corneal perforation, and three (21.4%) had a history of dry eye. Gram-negative organisms (7), Staphylococcus aureus (3), streptococcal species (2), and fungi (4) were the most frequently isolated organisms. Coagulase-negative staphylococci were not isolated. Six (42.9%) patients achieved a post-treatment visual acuity of 20/200 or better. Three (21.4%) patients underwent enucleation or evisceration. Although not statistically significant, there was an association between appropriate initial antibiotic therapy and improved visual outcomes.

CONCLUSION

Patients in whom endophthalmitis associated with microbial keratitis develops have a frequent history of corticosteroid use, systemic conditions associated with relative immune dysfunction, lack of an intact posterior capsule, dry eye, wound abnormalities, and/or corneal perforation. In general, agents cultured consisted of organisms less frequently reported to be the causative agents in series of postoperative and post-traumatic endophthalmitis. Post-treatment visual outcomes generally were poor.

Mycotic keratitis--an underestimated mycosis

Mycotic keratitis, an important ophthalmologic problem, especially in outdoor workers in the tropics, is frequently caused by filamentous fungi such as species of Fusarium, Aspergillus and Curvularia, and by yeast-like fungi such as Candida. A rapid, presumptive diagnosis can be made by recognition of certain typical clinical features and by direct microscopic detection of fungi in corneal scrapings stained by various methods. The diagnosis is confirmed by culture. In difficult cases, microbiological studies on corneal biopsies or histopathological studies on tissue sections may need to be performed. The use of fluorescein-conjugated lectins and similar diagnostic tools is aimed at providing rapid, species-specific detection of fungi in corneal tissue. Antifungal therapy must be instituted as soon as the diagnosis is made. While keratitis due to Aspergillus, Candida and dematiaceous fungi can be successfully treated by many of the currently available polyenes and azoles, the treatment of Fusarium keratitis still frequently requires the use of pimaricin or econazole. Treatment by the oral and parenteral routes may prove useful in severe mycotic keratitis. Surgery may need to be performed on cases unresponsive to medical therapy or where serious complications are likely to occur. The pathogenesis of mycotic keratitis appears to involve agent factors, such as invasiveness and toxigenicity, and host factors, such as trauma and intrinsic defects in resistance. Areas for future research include the development of rapid, species-specific diagnostic aids, of broad-spectrum antifungal compounds active by various routes, and of therapeutic modalities which act on the fungus and on molecules involved in the pathogenesis of the condition.

The importance of initial management in the treatment of severe infectious corneal ulcers

PURPOSE

To identify factors that influence the outcome of patients with severe infectious corneal ulcers.

METHOD

A retrospective review was performed of the hospital records of all such patients admitted to the Doheny Eye Hospital during a 30 month period. Outcome variables examined were change in visual acuity, duration of hospitalization, hospital charges, and percentage of patients who required penetrating keratoplasty.

RESULTS

Sixty-two ulcers were included. An organism was identified and antibiotic sensitivities established in 52 patients (84%). Inpatient therapy involved a combination of fortified aminoglycoside and cephalosporin antibiotics in 39 patients (63%) and was found to be appropriate on the basis of sensitivity studies in 49 (94%) of 52 patients. Inappropriate initial treatment was related to increased hospital charge (P = 0.024) as well as increased risk of penetrating keratoplasty (P = 0.001).

CONCLUSIONS

Appropriate initial therapy is most critical in the course of serious corneal ulcers, and aggressive, broad-spectrum antibiotic coverage is advocated.

Responsiveness of the National Eye Institute Visual Function Questionnaire to changes in visual acuity: findings in patients with subfoveal choroidal neovascularization--SST Report No. 1

BACKGROUND

The National Eye Institute Visual Function Questionnaire (NEI-VFQ) measures vision-targeted quality of life, but it is unclear whether it is sensitive to changes within individuals over time.

OBJECTIVE

To determine the responsiveness of the NEI-VFQ to "within-individual" changes in visual acuity in patients who had subfoveal choroidal neovascularization in at least one eye secondary to age-related macular degeneration, ocular histoplasmosis syndrome, or idiopathic causes, and who participated in randomized trials of submacular surgery.

METHODS

Trained telephone interviewers administered the NEI-VFQ as part of annual follow-up data collection for pilot trials and larger clinical trials of submacular surgery. Best-corrected visual acuity was measured by local vision examiners at 12 months after enrollment and, typically, by central "traveling" vision examiners at 24 months after enrollment. Changes in visual acuity and NEI-VFQ scores from 12 to 24 months were analyzed using linear regression methods.

RESULTS

Two-hundred eighteen patients had both interviews and visual acuity measurements at 12 and 24 months after enrollment. Changes in the overall NEI-VFQ score and in 9 of the subscales (near activities, dependency, driving, role difficulties, distance activities, mental health, general vision, peripheral vision, and social functioning) were related to changes in visual acuity of the better-seeing eye based on linear regression analysis (P<.05). In our analysis, a 3-line decrease in the visual acuity of the better-seeing eye was associated with 3.6- to 16.2-point decreases in the overall NEI-VFQ score and 9 subscale scores.

CONCLUSIONS

Most of the NEI-VFQ subscales were responsive to changes in the visual acuity of the better-seeing eye over a 12-month interval in this patient population. Thus, the NEI-VFQ can be used to measure change in vision-targeted quality of life over time to augment clinical measurements of visual acuity.

Photodynamic therapy of subfoveal choroidal neovascularization with verteporfin in the ocular histoplasmosis syndrome: one-year results of an uncontrolled, prospective case series

OBJECTIVE

To evaluate the safety and effect on visual acuity of photodynamic therapy with verteporfin (Visudyne, Novartis AG) in patients with subfoveal choroidal neovascularization (CNV) secondary to the ocular histoplasmosis syndrome (OHS).

DESIGN

Open-label, three-center, noncomparative prospective case series.

PARTICIPANTS

OHS patients with subfoveal CNV lesions no larger than 5400 micro m in greatest linear dimension (GLD) with classic or occult CNV extending under the geometric center of the foveal avascular zone and best-corrected visual acuity letter score of 73 to 34 (approximate Snellen equivalent 20/40-20/200).

METHODS

Twenty-six patients received verteporfin (6 mg/m(2)) infused IV over 10 minutes. Fifteen minutes after the start of infusion, a laser light at 689 nm delivered 50 J/cm(2) at an intensity of 600 mW/cm(2) over 83 seconds using a spot size with a diameter 1000 micro m larger than the GLD of the lesion. At 3-month follow-up examinations, retreatment with the same regimen was applied if angiography showed fluorescein leakage. Safety assessments were also made.

MAIN OUTCOME MEASURES

Visual function measurements were the changes from baseline in visual acuity and contrast sensitivity scores and the proportion of patients who, based on best-corrected visual acuity scores, (1) gained 7 or more letters, (2) lost 8 or more letters, and (3) lost 15 or more letters.

RESULTS

One patient was omitted from the study at the month 3 examination for not meeting the visual acuity eligibility requirements at baseline. By the month 12 examination, but excluding any retreatment at that visit, patients had received an average of 2.9 treatments of a maximum of 4 possible treatments. The month 12 median improvement from baseline in visual acuity of the remaining 25 patients was 7 letters, and median contrast sensitivity improved by 2 letters. Median visual acuity improvement was also 7 letters when three patients, who failed to meet all photographic eligibility requirements at baseline, were excluded. At the month 12 examination, 14 (56%) patients gained 7 or more letters of visual acuity from baseline, whereas 4 (16%) patients lost 8 or more letters, of which 2 (8%) lost 15 or more letters. No serious systemic or ocular adverse events were reported.

CONCLUSIONS

Median visual acuity improved after verteporfin therapy for at least 1 year in a small uncontrolled prospective case series of patients with subfoveal CNV caused by OHS. Verteporfin therapy seemed to be safe and well tolerated in these patients. Two-year data from this study will provide important, additional information on the safety and effect of verteporfin therapy for the treatment of subfoveal CNV secondary to OHS.

Photodynamic therapy with verteporfin in ocular histoplasmosis: uncontrolled, open-label 2-year study

OBJECTIVE

To evaluate the safety, effect on visual function, and fluorescein angiographic appearance of subfoveal choroidal neovascularization (CNV) through 2 years after photodynamic therapy with verteporfin (Visudyne; Novartis AG, Basel, Switzerland) in patients with ocular histoplasmosis syndrome (OHS).

DESIGN

Open-label, 3-center, uncontrolled clinical study.

PARTICIPANTS

Ocular histoplasmosis syndrome patients with subfoveal CNV (N = 26) with a greatest linear dimension no larger than 5400 microm with classic or occult CNV extending under the geometric center of the fovea, and best-corrected visual acuity letter score of approximately 20/40 to 20/200.

METHODS

The methods were similar to those described in the 1-year results with follow-up examinations every 3 months continuing through the second year. During the second year, additional therapy was recommended if fluorescein angiography showed leakage at a scheduled visit.

MAIN OUTCOME MEASUREMENTS

Visual function measurements included the changes from baseline in visual acuity and contrast sensitivity scores. Lesion size and leakage from classic and occult CNV were assessed at month 12 and month 24. Safety assessments also were made.

RESULTS

A 24-month examination was completed in 22 of the 26 enrolled participants (85%). At the 24-month examination, median improvement from baseline in visual acuity of the 22 patients evaluated was 6 letters; median contrast sensitivity improved by 3.5 letters. At the 24-month examination, 10 patients (45%) gained 7 or more letters of visual acuity from baseline, whereas 4 patients (18%) lost 8 or more letters, including 2 patients (9%) who lost at least 15 letters. There was absence of fluorescein angiographic leakage from classic CNV in 17 of the 20 evaluable lesions (85%), and leakage from occult CNV was absent in all eyes. No serious ocular adverse events were reported, and no serious systemic event was considered to be associated with treatment.

CONCLUSIONS

Median visual acuity improved and fluorescein angiographic leakage decreased after verteporfin therapy in this small, uncontrolled clinical study of patients with subfoveal CNV resulting from OHS. Verteporfin therapy seemed to be relatively safe in these patients. The selected cases feature fluorescein angiographic examples of CNV that are important in determining when to apply verteporfin therapy.

Evaluation of minimum clinically meaningful changes in scores on the National Eye Institute Visual Function Questionnaire (NEI-VFQ) SST Report Number 19

PURPOSE

To evaluate responsiveness of the National Eye Institute Visual Function Questionnaire (NEI-VFQ) to changes in visual acuity and to provide estimates of minimum clinically meaningful changes in NEI-VFQ scores.

METHODS

Data were combined from three clinical trials of submacular surgery for subfoveal choroidal neovascularization. Patients who completed NEI-VFQ interviews and visual acuity measurements at baseline and 2 years later contributed data for analysis. Data were analyzed using anchor-based (relating 2-year change in NEI-VFQ to 2-year change in visual acuity using correlation and linear regression) and distribution-based (standardized response mean) methods.

RESULTS

Of 1,015 patients enrolled, 828 patients completed NEI-VFQ interviews and had visual acuity measurements at baseline and 2 years later. Median age of patients was 75 years (range 18 to 94); all patients had subfoveal choroidal neovascularization in at least one eye. Median overall NEI-VFQ score at baseline was 69.9 (mean, 66.5). Based on anchor-based methods, a 2-line change in visual acuity of the better-seeing eye translated to a 3.4-point change in the overall NEI-VFQ score and from 2.4-point to 7.0-point changes in most subscale scores. The NEI-VFQ was sensitive to both gains and losses in visual acuity; the standardized response mean for the overall NEI-VFQ score in patients with a 2-line gain was 0.6 and for patients with 2-line loss was -0.3. In the subgroup of patients with a 2-line loss of visual acuity in the better-seeing eye, patients who had overall NEI-VFQ scores at baseline greater than the median (59.8) had an standardized response mean of -0.9 for the overall NEI-VFQ score and patients who had overall NEI-VFQ scores at baseline at or below the median had a standardized response mean of 0.2 for the overall NEI-VFQ score. A 4-point change in the overall NEI-VFQ and a 5-point change in individual subscale scores corresponded to a small clinically meaningful change.

CONCLUSIONS

The NEI-VFQ was responsive to 2-year changes in visual acuity but was less responsive to changes among patients with poorer NEI-VFQ scores at baseline. Based on this analysis, a 4-point change in the overall NEI-VFQ and a 5-point change in individual subscale scores may be considered minimum clinically meaningful within-person changes in NEI-VFQ scores.

Amniotic Membrane Transplantation for Persistent Corneal Ulcers and Perforations in Acute Fungal Keratitis

PURPOSE

To report the therapeutic effect and complications of amniotic membrane transplantation (AMT) in acute fungal keratitis.

METHODS

Diagnosis of fungal keratitis was confirmed by cultures in 23 eyes of 23 patients. The indications to perform AMT were to promote reepithelialization in non-healing ulcers or to prevent corneal perforation. Antifungal agents were administered throughout the whole course of hospitalization. Repeated cultures were performed immediately before AMT. The main outcome measurements were epithelial healing rate, necessity of therapeutic penetrating keratoplasty (TPK), and persistence of infection.

RESULTS

During a mean follow-up time of 20.6 months +/- 23.22 (6-65 months) AMT was performed during the active phase of the keratitis (fungal culture was still positive) in 16 patients (69.6%), and during the inactive phase (fungal culture negative) in 7 patients (30.4%). Single-layer AMT was performed in 17 patients, and double-layer AMT was performed in 6 patients with corneal perforation and anterior chamber collapse. Complete epithelialization was observed in 12 patients (75%) in the active group and in 7 patients (100%) in the inactive group. Treatment failure requiring TPK was experienced in 4 patients (25%) in the active group. Persistent fungal keratitis was noted in 2 patients (8.7%) in that group. The final visual acuity improved in 17 cases, worsened in 2 cases, and remained unchanged in 4 cases. Twelve of the 23 eyes (52.2%) in this study preserved useful vision (20/400 and better) with or without subsequent surgeries.

CONCLUSION

AMT is effective in promoting epithelialization and preventing corneal perforations in acute fungal keratitis, and there is no risk of rejection. However, the risk of persistent or recurrent infection necessitates continued antifungal treatment and patient monitoring.

Immunosuppression Affects the Severity of ExperimentalFusarium solaniKeratitis

We have established a mouse model of corneal fusariosis that permits the evaluation of fungal infection and pathogenesis. Corneas of immunocompetent and cyclophosphamide-treated adult BALB/c mice were topically inoculated with Fusarium solani after corneal scarification. Eyes were scored for corneal involvement daily for 8 days and at 2 weeks after infection. Eyes were enucleated at various time points for quantitative fungal recovery and histopathological examination. An inoculum-dose response was observed in cyclophosphamide-treated mice, and fungi were recovered from the infected eyes by quantitative microbial culturing. Treatment with cyclophosphamide increased disease severity and delayed fungal clearance. Fungal hyphae, inflammatory cells, and stromal edema were histologically evident within corneal tissue and correlated with disease severity. Although the mouse cornea resists fungal infections, F. solani keratitis could be induced in immunosuppressed mice after surface scarification, which resulted in infection and clinical disease that could be evaluated both in vivo and in vitro.

Endogenous endophthalmitis by Fusarium solani: an animal experimental model

An experimental model of endophthalmitis by Fusarium solani in immunocompetent mice that could be useful for evaluating the efficacy of different treatments and the pathogenicity of the fungus in ocular structures was established. Five clinical isolates of F. solani were injected into the lateral tail vein of groups of 20 mice, in order to produce systemic infection with ocular infection. Inocula of 5 x 10(6) conidia per mouse were used. The eyes of the animals that died were enucleated for histopathological study to determine the degree of ocular infection. We found fungal infections in 34% of the mice studied. Panophthalmitis was detected in 16 animals, four with bilateral infections. Fungal endophthalmitis can become a severe complication of systemic mycoses by F. solani.

Scanning laser ophthalmoscope fundus perimetry after surgery for choroidal neovascularization

PURPOSE

Submacular surgery is under investigation for the treatment of subfoveal choroidal neovascularization secondary to age-related macular degeneration, ocular histoplasmosis syndrome, and other causes. The aims of this study were to determine whether the macular area from which choroidal neovascularization was removed surgically remained functional and whether there was any qualitative difference between eyes with different disease conditions or between eyes of younger and older patients.

METHODS

Our study included 19 patients (19 eyes) with choroidal neovascularization, seven cases caused by age-related macular degeneration and 12 caused by ocular histoplasmosis syndrome, pathologic myopia, or idiopathic causes. All tests were performed at least 6 months after surgical removal of choroidal neovascularization. All patients underwent fundus perimetry with the scanning laser ophthalmoscope for evaluation of dense and relative scotomas and fixation site.

RESULTS

After submacular surgery in 19 patients, 10 patients (one with age-related macular degeneration and nine with pathologic myopia, ocular histoplasmosis syndrome, or an idiopathic cause of choroidal neovascularization) fixated within an area that ophthalmoscopically and angiographically was an area of retinal pigment epithelial disturbance occupied by choroidal neovascularization preoperatively. Of 12 patients without age-related macular degeneration, seven of eight patients younger than 50 years of age compared with two of four patients 50 years or older fixated within the area of retinal pigment epithelial disturbance.

CONCLUSIONS

Our data suggest that in patients without age-related macular degeneration who undergo submacular surgery, the surgically disturbed area previously occupied by choroidal neovascularization can remain functional postoperatively. Furthermore, occasionally a patient with age-related macular degeneration undergoing submacular surgery still can fixate in the area from which the choroidal neovascularization was removed.

New and classic insights into presumed ocular histoplasmosis syndrome and its treatment

PURPOSE OF REVIEW

Presumed ocular histoplasmosis syndrome classically presents with atrophic choroidal scars, which are thought to progress into choroidal neovascularization in a small proportion of patients. The pathophysiology of the disease, including its underlying etiology, continues to be controversial and subject to ongoing research. Even more important is the controversy that surrounds the optimal treatment for choroidal neovascularization in patients with presumed ocular histoplasmosis, in particular that of subfoveal localization.

RECENT DEVELOPMENTS

Intense efforts oriented toward defining the most beneficial therapeutic modality have resulted in some well-designed, large studies that evaluated submacular surgery, photodynamic therapies, and anti-angiogenic therapies, as well as small pilot studies exploring new therapeutic approaches for choroidal neovascularization.

SUMMARY

Important results obtained by these studies were recently made public, and the conclusions that may be drawn from them, as well as an update on findings concerning presumed ocular histoplasmosis etiology, epidemiology, and pathophysiology are presented in this report.

Endogenous Pseudallescheria boydii endophthalmitis. Clinicopathologic findings in two cases

Two cases of endogenous Pseudallescheria boydii endophthalmitis are presented. One patient had severe pulmonary fibrosis but no history of ocular trauma and no clinical or laboratory evidence of immunocompromise. Despite therapy with repeated intravitreal miconazole nitrate injections and systemic fluconazole, enucleation of the globe was required, and the patient eventually died with disseminated pseudallescheriasis. The other patient was an immunosuppressed cardiac transplant recipient who also received systemic fluconazole therapy. The infected eye eventually required evisceration, but there was no evidence of disseminated pseudallescheriasis before his death of unrelated causes.

The efficacy of corneal debridement in the treatment of microsporidial keratoconjunctivitis: a prospective randomized clinical trial

PURPOSE

To evaluate the efficacy of corneal debridement in the treatment of clinically diagnosed cases of microsporidial keratoconjunctivitis.

DESIGN

Prospective, double-masked randomized clinical trial.

METHODS

Patients with clinical features such as multifocal, coarse, raised, punctate, round to oval epithelial lesions in the cornea in slit-lamp examination with mild to moderate conjunctival congestion, suggestive of microsporidial superficial keratoconjunctivitis, were included in the prospective study. All patients were randomized into 2 groups. Group 1 patients underwent debridement with the help of a sterile #15 blade on a Bard-Parker handle, whereas only conjunctival swabs were taken from Group 2 patients. All patients were treated with ocular lubricants.

RESULTS

One hundred and twenty patients with clinical features suggestive of microsporidial superficial keratoconjunctivitis were included in the study. The mean age was 34.3 ± 13.6 years (Group 1) and 35.8 ± 16.2 years (Group 2) (P = .59). The mean duration of symptoms was 6.8 ± 3.9 days (Group 1) and 7.2 ± 4.6 days (Group 2) (P = .61). Baseline characteristics showed no difference between the 2 groups. The primary outcome was the time from the presentation to complete resolution (ie, absence of corneal lesions) of the clinical signs and symptoms. The secondary outcomes were final visual acuity and residual corneal side effects and/or scarring, if any. The mean resolution time of the corneal lesions was 5.7 ± 4.0 days (Group 1) and 5.9 ± 3.9 days (Group 2) (P = .83). There was no significant difference in final visual outcome in the 2 groups. No serious side effects were observed.

CONCLUSION

Debridement does not have any significant advantage in terms of resolution of the corneal lesions and final visual outcome in cases of microsporidial keratoconjunctivitis.

Electroretinographic alterations during vitrectomy in human eyes

BACKGROUND

We previously reported a new system of electroretinographic monitoring of the retinal function during vitrectomy in human eyes, and found that lowering the intravitreal temperature by applying an infusion solution kept at room temperature (used routinely for vitrectomy throughout the world) can alter the electroretinogram (ERG). This time we attempted to study the effect upon the ERG of replacing the intraocular medium and acutely elevating the intraocular pressure during vitrectomy.

METHODS

Using a special contact lens with a built-in light-emitting diode light source, 30-Hz flicker ERG was quickly recorded under aseptic conditions.

RESULTS

Acute, reversible reduction in amplitude was observed upon replacing the intraocular medium with air or silicon oil and during periods of acutely elevated intraocular pressure. Infusions of gentamicin or miconazole did not affect the ERG when intravitreal temperature and intraocular pressure were constant.

CONCLUSION

The ERG monitor can reveal changes of the retinal function during vitrectomy, particularly when the infusion temperature, intraocular medium and intraocular pressure are kept constant.

Scanning laser ophthalmoscope macular perimetry in the evaluation of submacular surgery

PURPOSE

Submacular surgery for choroidal neovascularization (CNV) is under investigation in the treatment of age-related macular degeneration (AMD) and the presumed ocular histoplasmosis syndrome. Four case studies are presented to demonstrate scanning laser ophthalmoscope (SLO) testing in the pre- and postsurgical evaluation of visual function in patients with subfoveal CNV secondary to AMD, presumed ocular histoplasmosis syndrome, and submacular hemorrhage secondary to AMD.

METHODS

Patients underwent a visual assessment pre- and 6 months postoperatively, consisting of low vision visual acuity measurement, SLO macular perimetry of dense and relative scotomas, and analysis of the preferred retinal locus for fixation (PRL) location and ability.

RESULTS

Visual acuity, dense and relative scotoma size and location, and PRL location were compared; and relationships between anatomic and functional changes were observed. Decreases in scotoma size and improvement in PRL location and ability usually corresponded with improved visual acuity. Preoperative scotoma and PRL location guided retinotomy site selection.

CONCLUSION

Scanning laser ophthalmoscope macular perimetry and PRL testing may be useful adjuncts in the visual assessment of submacular surgery and may advance under-standing of the effects of submacular surgery on visual function. In addition, this testing may be used to plan location of surgical interventions for macular diseases.

Retinal Function Assessed by ERG Before and After Induction of Ocular Aspergillosis and Treatment by the Anti-fungal, Micafungin, in Rabbits

This study was conducted to evaluate the effectiveness of a new antifungal drug, micafungin, and standard antifungal drugs against endophthalmitis induced in a rabbit by intravitreal injection of Aspergillus fumigatus, an important fungal pathogen. Effectiveness was evaluated by the preservation of b-wave amplitude at 72 h after injection of the fungus relative to the b-wave amplitude at baseline before any intravitreal injections. A 0.06 ml inoculum of 10(6) conidia of A. fumigatus was injected into the vitreous of the right eye of all rabbits; and, 12 h later, a 0.06 ml solution containing one of 3 antifungal drugs or saline was injected into the vitreous of both eyes. All three antifungal drugs produced significant b-wave preservation at 72 h in infected eyes compared to that in infected eyes receiving saline injections. There was no statistically significant difference between the effects of micafungin and amphotericin B in the right eyes with fungal endophthalmitis, and both produced significantly more preservation of b-wave amplitude than voriconazole. Amphotericin B, but neither micafungin nor voriconazole produced significant reduction of the b-wave amplitude in the left eyes.

Anterior ocular infections: an overview of pathophysiology and treatment

OBJECTIVE

To provide a review of the pathophysiology and treatment of anterior ocular infections.

DATA SOURCE

A MEDLINE search (from 1970 to October 1998) as well as a review of the tertiary literature was performed to identify pertinent literature on pathophysiology and treatment of ocular infections.

STUDY SELECTION AND DATA EXTRACTION

All articles were considered for possible inclusion in the review. Relevant studies were selected for discussion in the article.

DATA SYNTHESIS

Ocular infections are common and vary from self-limiting to sight-threatening. Infections occur in different eye structures; presentation and treatment vary accordingly. Infections can occur when tissues of the eye are exposed to pathogens not normally present, when the eye is damaged, allowing pathogens to overcome the natural defenses of the eye, or in immunosuppressed patients where normal flora may become opportunistic. In deciding on appropriate treatment, both the causative pathogen and the structure(s) affected must be considered. The most likely pathogen can often be determined based on clinical signs and symptoms, patient history, or, in some cases, may need to be determined microbiologically. Differences in drug absorption, penetration, and availability to the various structures of the eye affect treatment decisions. Severity of infection, efficacy and safety of medication, and cost/benefit ratios must be taken into consideration in choosing the proper pharmacologic management of various ocular infections.

CONCLUSIONS

Treatment of ocular infections depends on knowledge of the pathophysiology and drug disposition at the site of infection. An understanding of the current concepts surrounding the management of the anterior ocular infections presented will aid in the provision of optimal patient care.