Reactivations of ocular toxoplasmosis after cataract extraction

Association Between Ocular Trauma and Activation of Ocular Toxoplasmosis

PURPOSE

To evaluate the association between ocular trauma and activation of ocular toxoplasmosis.

METHODS

Retrospective review of 686 patients with ocular toxoplasmosis and its association with trauma to the eye or the head within 1 week of activation.

RESULTS

Ten patients with a history of trauma and activation of ocular toxoplasmosis were detected (10/686; 1.45%). Nine patients showed a primary focus of retinitis without a previous scar and one patient had a recurrent form of ocular toxoplasmosis. From these 10 patients, Toxoplasma IgG was positive in eight of them. The median age of the patients was 35.8 years-old (range 17 to 65).

CONCLUSIONS

These cases suggest that trauma can be associated with activation of retinal bradyzoite cysts in ocular toxoplasmosis.

Recurrence of Ocular Toxoplasmosis after Vitrectomy: Case Report and Review

PURPOSE

The purpose of this study is to report one case of ocular toxoplasmosis (OT) recurrence after vitrectomy and review the scientific basis about it.

CASE REPORT

A 58-year-old male patient with previous OT, properly treated, underwent vitrectomy due to macular hole. During follow-up, patient evolved with recurrence of the OT. After 1 year, patient presents visual acuity of 20/200 and extensive macular scar.

CONCLUSION

There is no consensus on using perioperative antiparasitic therapy aiming recurrence prophylaxis. Studies with better statistical design are necessary to evaluate the recurrence risk after ocular surgeries and the possible recommendation of prophylaxis, especially in countries where the strains are more virulent and the recurrence more common.

Risk factors for recurrences and visual impairment in patients with ocular toxoplasmosis: A systematic review and meta-analysis

BACKGROUND

Ocular toxoplasmosis (OT) is caused by the parasite Toxoplasma gondii. OT is the leading cause of posterior uveitis globally; it is a recurrent disease that may result in visual impairment and blindness. This systematic review and meta-analysis aim to summarize and evaluate the risk factors for recurrences, visual impairment, and blindness described in the literature worldwide.

METHODS AND FINDINGS

We performed a systematic literature search in PubMed, Embase, VHL, Cochrane Library, Scopus, and DANS EASY Archive. All studies reporting patients with clinically and serologically confirmed OT presenting any clinical or paraclinical factor influencing recurrences, visual impairment, and blindness were included. Studies presenting secondary data, case reports, and case series were excluded. An initial selection was made by title and abstract, and then the studies were reviewed by full text where the eligible studies were selected. Then, the risk of bias was assessed through validated tools. Data were extracted using a validated extraction format. Qualitative synthesis and quantitative analysis were done. This study was registered on PROSPERO (CRD42022327836).

RESULTS

Seventy two studies met the inclusion criteria. Fifty-three were summarized in the qualitative synthesis in three sections: clinical and environmental factors, parasite and host factors, and treatment-related factors. Of the 72 articles, 39 were included in the meta-analysis, of which 14 were conducted in South America, 13 in Europe, four in Asia, three multinational, two in North America and Central America, respectively, and only one in Africa. A total of 4,200 patients with OT were analyzed, mean age ranged from 7.3 to 65.1 year of age, with similar distribution by sex. The frequency of recurrences in patients with OT was 49% (95% CI 40%-58%), being more frequent in the South American population than in Europeans. Additionally, visual impairment was presented in 35% (95% CI 25%-48%) and blindness in 20% (95% CI 13%-30%) of eyes, with a similar predominance in South Americans than in Europeans. On the other hand, having lesions near the macula or adjacent to the optic nerve had an OR of 4.83 (95% CI; 2.72-8.59) for blindness, similar to having more than one recurrence that had an OR of 3.18 (95% CI; 1.59-6.38). Finally, the prophylactic therapy with Trimethoprim/Sulfamethoxazole versus the placebo showed a protective factor of 83% during the first year and 87% in the second year after treatment.

CONCLUSION

Our Systematic Review showed that clinical factors such as being older than 40 years, patients with de novo OT lesions or with less than one year after the first episode, macular area involvement, lesions greater than 1 disc diameter, congenital toxoplasmosis, and bilateral compromise had more risk of recurrences. Also, environmental and parasite factors such as precipitations, geographical region where the infection is acquired, and more virulent strains confer greater risk of recurrences. Therefore, patients with the above mentioned clinical, environmental, and parasite factors could benefit from using prophylactic therapy.

Ocular toxoplasmosis, an overview focusing on clinical aspects

Toxoplasma gondii is a widespread protozoan parasite infecting approximately one third of the world population. After proliferation of tachyzoites during the acute stage, the parasite forms tissue cysts in various anatomical sites and establishes chronic infection. Nowadays the nature of the interplay between the protozoan and its human host remains elusive. This is clearly evident in ocular toxoplasmosis, in which the parasite establishes an ambivalent relationship with the eye, manipulating the immune response and inducing variable initial lesions and further relapses. This review will focus on epidemiology and environmental, parasite and host related risk factors, clinical manifestations and laboratory findings, treatment and prophylaxis approaches in ocular toxoplasmosis. An image collection of patients referred to the Unit of Ophthalmology of Pisa's Hospital will be presented, too.

Pathophysiology of ocular toxoplasmosis: Facts and open questions

Infections with the protozoan parasite Toxoplasma gondii are frequent, but one of its main consequences, ocular toxoplasmosis (OT), remains poorly understood. While its clinical description has recently attracted more attention and publications, the underlying pathophysiological mechanisms are only sparsely elucidated, which is partly due to the inherent difficulties to establish relevant animal models. Furthermore, the particularities of the ocular environment explain why the abundant knowledge on systemic toxoplasmosis cannot be just transferred to the ocular situation. However, studies undertaken in mouse models have revealed a central role of interferon gamma (IFNγ) and, more surprisingly, interleukin 17 (IL17), in ocular pathology and parasite control. These studies also show the importance of the genetic background of the infective Toxoplasma strain. Indeed, infections due to exotic strains show a completely different pathophysiology, which translates in a different clinical outcome. These elements should lead to more individualized therapy. Furthermore, the recent advance in understanding the immune response during OT paved the way to new research leads, involving immune pathways poorly studied in this particular setting, such as type I and type III interferons. In any case, deeper knowledge of the mechanisms of this pathology is needed to establish new, more targeted treatment schemes.

Clinical, Socio-economic and Environmental Factors Related with Recurrences in Ocular Toxoplasmosis in Quindío, Colombia

PURPOSE

To identify the sociodemographic, clinical, and environmental factors associated with recurrences in ocular toxoplasmosis (OT).

METHODS

Retrospective analysis of clinical records of patients who consulted in the Health Centre at Universidad del Quindío between 2004 and 2017. Patients with retinochoroiditis due to Toxoplasma gondii infection and follow up >12 months were included. Comparisons were made with a recurrence index adjusted for months of follow up. For the statistical analysis, the Kruskal-Wallis test and analysis of variance (ANOVA) tests were performed in Epi Info 7.2 and SPSS 14.0. A statistical significance is shown if p ≤ 0.05.

RESULTS

A total of 58 patients were included, with median age of 28 years (range 1-61) and 55.1% were women. The median of recurrences was 1.4 (range 0.6-16.6). High recurrence index was present in 43.1% of the patients. A higher size of lesions was observed in low socioeconomic groups (p = .016) and patients with congenital infection had more bilateral compromise (p = .002). Intake of boiled water was related to a lower recurrence index (p = .04).

CONCLUSIONS

Low socioeconomic level was associated with bigger lesions and congenital infection was related with higher frequency of bilateral OT. Finally, intake of boiled water is related to a lower recurrence index of OT.

Toxoplasma gondii infection drives conversion of NK cells into ILC1-like cells

Innate lymphoid cells (ILCs) were originally classified based on their cytokine profiles, placing natural killer (NK) cells and ILC1s together, but recent studies support their separation into different lineages at steady-state. However, tumors may induce NK cell conversion into ILC1-like cells that are limited to the tumor microenvironment and whether this conversion occurs beyond this environment remains unknown. Here, we describe Toxoplasma gondii infection converts NK cells into ILC1-like cells that are distinct from both steady-state NK cells and ILC1s in uninfected mice. These cells were Eomes-dependent, indicating that NK cells can give rise to Eomes^- Tbet-dependent ILC1-like cells that circulate widely and persist independent of ongoing infection. Moreover, these changes appear permanent, as supported by epigenetic analyses. Thus, these studies markedly expand current concepts of NK cells, ILCs, and their potential conversion.

Clinical and Biological Factors Associated With Recurrences of Severe Toxoplasmic Retinochoroiditis Confirmed by Aqueous Humor Analysis

PURPOSE

To investigate clinical and biological factors influencing recurrences of severe toxoplasmic retinochoroiditis (TRC) confirmed by aqueous humor analysis.

DESIGN

Retrospective case series.

METHODS

Retrospective analysis of 87 subjects with severe TRC, proven by positive Goldmann-Witmer coefficient (GWC), Toxoplasma gondii (T. gondii) immunoblot, or T. gondii-specific polymerase chain reaction (PCR) in aqueous humor. Cases with immunosuppression or retinal scars without previous recorded episode were excluded. Time-dependent, clinical, treatment-related, and biological factors were explored by univariate and multivariate shared frailty survival analyses.

RESULTS

Among 44 included subjects (age, 40.4 ± 17.6 years; follow-up, 8.3 ± 2.7 years), 22 presented recurrences. There was 0.11 recurrence/patient/year and mean disease-free interval was 5.0 ± 2.9 years. The risk of recurrence was higher immediately after an episode (P < .0001). Among recurrent cases, the risk of multiple recurrences was higher when the first recurrence occurred after longer disease-free intervals (P = .046). In univariate analysis, the recurrence risk declined with higher number of intense bands on aqueous T. gondii immunoblot (P = .006), and increased when venous vasculitis was present initially (P = .019). Multivariate analysis confirmed that eyes with more intense bands on immunoblot had fewer recurrences (P = .041). There was a near-significant risk elevation after pyrimethamine/azithromycin treatment (P = .078 and P = .054, univariate and multivariate). Intravenous corticosteroid administration, oral corticosteroid administration, aqueous GWC, and T. gondii PCR did not influence recurrences (P = .12, P = .10, P = .39, and P = .96, respectively).

CONCLUSIONS

Recurrences of severe TRC are not random and may be influenced by clinical and biological factors possibly related to blood-retinal barrier alterations. These results may contribute to identifying biomarkers for TRC reactivation.

Anatomical and functional outcomes of pars plana vitrectomy for inflammatory epiretinal membrane surgery in healed toxoplasmosis infection

Epiretinal membrane over macula secondary to toxoplasmosis compromises vision. We describe the outcome of pars plana vitrectomy and epiretinal membrane removal after adequate treatment of acute infection. The average age of all four male patients was 36 years (range 20–60 years). Following surgery there was an average three or more lines visual acuity improvement, restoration of foveal contour with reduction in central macular thickness. One patient developed choroidal neovascular membrane postsurgery and was effectively treated with intravitreal bevacizumab. Surgery for ERM secondary to healed toxoplasmosis infection has good anatomical outcome and reasonable visual improvement, when the surgery is done in a quiet eye.

Decision-making and management of uveitic cataract

The visual outcome of uveitic cataract surgery depends on the underlying uveitic diagnosis, the presence of vision-limiting pathology and perioperative optimization of disease control. A comprehensive preoperative ophthalmic assessment for the presence of concomitant ocular pathology, with particular emphasis on macula and optic nerve involvement, is essential to determine which patients will benefit from improved vision after cataract surgery. Meticulous examination in conjunction with adjunct investigations can help in preoperative surgical planning and in determining the need for combined or staged procedures. The eye should be quiescent for a minimum of 3 months before cataract surgery. Perioperative corticosteroid prophylaxis is important to reduce the risk of cystoid macular edema and recurrence of the uveitis. Antimicrobial prophylaxis may also reduce the risk of reactivation in eyes with infectious uveitis. Uveitic cataracts may be surgically demanding due to the presence of synechiae, membranes, and pupil abnormalities that limit access to the cataract. This can be overcome by manual stretching, multiple sphincterotomies or mechanical dilation with pupil dilation devices. In patients <2 years of age and in eyes where the inflammation is poorly controlled, intraocular lens implantation should be deferred. Intensive local and/or oral steroid prophylaxis should be given postoperatively if indicated. Patients must be monitored closely for disease recurrence, excessive inflammation, raised intraocular pressure, hypotony, and other complications. Complications must be treated aggressively to improve visual rehabilitation. With proper patient selection, improved surgical techniques and optimization of peri- and post-operative care, patients with uveitic cataracts can achieve good visual outcomes.

OUTCOMES AFTER PARS PLANA VITRECTOMY FOR EPIRETINAL MEMBRANES ASSOCIATED WITH TOXOPLASMOSIS

PURPOSE

To evaluate outcomes and complications of pars plana vitrectomy in patients with epiretinal membrane secondary to toxoplasmic retinochoroiditis.

METHODS

Retrospective evaluation of the records of 14 patients who underwent pars plana vitrectomy for epiretinal membrane secondary to toxoplasmic retinochoroiditis. The best-corrected visual acuity, intraoperative and postoperative complications, and macular optical coherence tomography were analysed. All patients received postoperative prophylactic treatment with trimethoprim/sulfamethoxazole.

RESULTS

Fourteen patients, 5 men and 9 women, were included. Mean follow-up period after surgery was 6.07 ± 2.64 months. Preoperative mean best-corrected visual acuity was 20/200, and postoperative mean best-corrected visual acuity was 20/60. There were no intraoperative complications. Three patients developed posterior capsule opacification, and one patient developed cataract.

CONCLUSION

Pars plana vitrectomy is a safe and effective procedure in patients with epiretinal membrane secondary to toxoplasmic retinochoroiditis, improving both visual acuity and anatomical result on macular optical coherence tomography. The most frequent postoperative complications were posterior capsule opacification and cataract. No recurrences of the disease were recorded.

Host and Toxoplasma gondii genetic and non-genetic factors influencing the development of ocular toxoplasmosis: A systematic review

Toxoplasmosis is a cosmopolitan infection caused by the apicomplexan parasite Toxoplasma gondii. This infectious disease is widely distributed across the world where cats play an important role in its spread. The symptomatology caused by this parasite is diverse but the ocular affectation emerges as the most important clinical phenotype. Therefore, we conducted a systematic review of the current knowledge of ocular toxoplasmosis from the genetic diversity of the pathogen towards the treatment available for this infection. This review represents an update to the scientific community regarding the genetic diversity of the parasite, the genetic factors of the host, the molecular pathogenesis and its association with disease, the available diagnostic tools and the available treatment of patients undergoing ocular toxoplamosis. This review will be an update for the scientific community in order to encourage researchers to deploy cutting-edge investigation across this field.

Clinical Features and Risk Factors of Patients with Presumed Ocular Toxoplasmosis

Purpose:

To determine the clinical features and risk factors of presumed ocular toxoplasmosis (POT) in patients affected with the condition at Irrua, Nigeria.

Methods:

The study included 69 patients with POT, and 69 age and sex matched subjects who served as the control group. Data was obtained using interviewer administered questionnaires. Examination included measurement of visual acuity (VA), intraocular pressure (IOP), slit lamp examination, gonioscopy and dilated fundus examination.

Results:

Mean age of cases and control subjects was 57.16 ± 18.69 and 56.09 ± 16.01 years respectively. The peak age group in patients with POT was 60 years and above. The most common presenting complaint was blurred vision occurring in 100% of cases. Drinking unfiltered water in 58 (84.1%) patients was the most common risk factor. Other risk factors included post cataract surgery status in 32 (46.4%) subjects, ingestion of poorly cooked meat in 30 (43.5%) cases and exposure to cats in 9 (13.0%) patients. All risk factors were more common in POT patients (P < 0.05). Out of 69 patients, 62 (89.9%) had unilateral while 7 (10.1%) had bilateral involvement. Out of 76 eyes with uveitis, 53 (69.7%) were blind. Active disease was significantly more common with increasing age (P < 0.05).

Conclusion:

Patients with POT were rather old and some risk factors were modifiable, therefore health education for preventing the transmission of toxoplasmosis and provision of sanitary water may help reduce the incidence of ocular toxoplasmosis.

Ocular toxoplasmosis: background and evidence for an antibiotic prophylaxis

PURPOSE OF REVIEW

The purpose of this review was to provide an overview of current data on antibiotic prophylaxis in ocular toxoplasmosis.

RECENT FINDINGS

Studies showing the prophylactic effect of long-term antibiotics are discussed. Prophylaxis seems to be justified in patients with a high risk of recurrence because of antibiotic's potential side-effects. Therefore, predisposing factors leading to a higher risk of recurrence and the time period during which an antibiotic prophylaxis is most appropriate are reviewed. Finally, a patient-individualized treatment recommendation is summarized.

SUMMARY

In the current literature, two prospective, randomized case-control studies exist, which show the protective effect of an antibiotic prophylaxis. Hematologic, gastrointestinal and dermatologic complications are potential side-effects. Especially during the first year after suffering a recurrence, an antibiotic prophylaxis seems to be justified. The risk of a recurrence is inter alia influenced by the duration of the disease, the immune status of the host and the patient's age. Therefore, an antibiotic prophylaxis should be considered for patients who have recently been infected with ocular toxoplasmosis, for middle-aged and elderly patients and patients with a compromised immune system. This should be discussed with each patient individually, especially if the lesion is close to the macula.

Experimental Models of Ocular Infection with Toxoplasma Gondii

Ocular toxoplasmosis is a vision-threatening disease and the major cause of posterior uveitis worldwide. In spite of the continuing global burden of ocular toxoplasmosis, many critical aspects of disease including the therapeutic approach to ocular toxoplasmosis are still under debate. To assist in addressing many aspects of the disease, numerous experimental models of ocular toxoplasmosis have been established. In this article, we present an overview on in vitro, ex vivo, and in vivo models of ocular toxoplasmosis available to date. Experimental studies on ocular toxoplasmosis have recently focused on mice. However, the majority of murine models established so far are based on intraperitoneal and intraocular infection with Toxoplasma gondii. We therefore also present results obtained in an in vivo model using peroral infection of C57BL/6 and NMRI mice that reflects the natural route of infection and mimics the disease course in humans. While advances have been made in ex vivo model systems or larger animals to investigate specific aspects of ocular toxoplasmosis, laboratory mice continue to be the experimental model of choice for the investigation of ocular toxoplasmosis.

Risk of reactivation of toxoplasmic retinitis following intraocular procedures without the use of prophylactic therapy

BACKGROUND/AIMS

Toxoplasmic retinochoroiditis is the commonest known cause of posterior uveitis worldwide and reactivation is unpredictable. Based on results from one study, the authors proposed that antitoxoplasmic therapy should be initiated as prophylaxis for intraocular surgery in patients with toxoplasmic scars. The aim of this study is to analyse the risk of toxoplasmic retinochoroiditis reactivation following intraocular procedures.

METHODS

Retrospective analysis of the medical records of a total of 69 patients who underwent intraocular surgery and presented with toxoplasmic retinochoroiditis scars.

RESULTS

No patient received prophylactic antitoxoplasmic therapy. Reactivation following the surgical procedure occurred in four cases, with one at 3 months and the others respectively at 13, 14 and 17 months.

CONCLUSIONS

Our study shows that intraocular surgery did not result in a significant reactivation rate of toxoplasmic retinochoroiditis in the absence of preoperative prophylactic antitoxoplasmic therapy.

Cataract surgery in patients with history of uveitis

Cataract surgery in patients with uveitis is not as simple as any senile cataract surgery. Recent evidence suggests that useful visual outcome can be achieved in most of the cases if they are handled meticulously. Key factors leading to improved visual outcome are absolute control of preoperative inflammation with diligent use of immunomodulatory drugs, meticulous surgery along with early detection and care of postoperative complications. Modern technologies in the intraocular lens designs and materials have contributed to the success. In this article, we review the literature on this subject with emphasis on the importance of the use of immunomodulatory drugs to control preoperative and postoperative intraocular inflammation and avoid complications.

Reactivation of ocular toxoplasmosis after pars plana vitrectomy

PURPOSE

To report a case with reactivation of toxoplasma choroiretinitis after pars plana vitrectomy.

PATIENTS AND METHODS

A 58-year-old female patient was diagnosed with secondary epiretinal membrane in her right eye. Bimanual 23-gauge pars plana vitrectomy and membrane peeling was performed. At first week postoperatively, visual acuity decreased; in slit-lamp examination, there were 3+ cells in the anterior chamber with keratic precipitate. Fundoscopic examination revealed reactivation of chorioretinitis adjacent to the previous scar.

RESULTS

The patient was diagnosed with reactivation of toxoplasma chorioretinitis and treated with oral trimethoprim-sulfamethoxazole, clindamycin and topical prednisolon acetate, and cyclopentolate drops for 5 weeks. Forty-eight hours after initiation of antibiotics, oral prednisone was added to the regimen and the dose was tapered to zero over the following 5 weeks. After 3 weeks of treatment, lesion was inactivated.

CONCLUSION

Ocular toxoplasmosis reactivation may develop after pars plana vitrectomy. After intraocular surgery, reactivation of ocular toxoplasmosis should be considered in the follow-up.

Ocular toxoplasmosis II: clinical features, pathology and management

The term, ocular toxoplasmosis, refers to eye disease related to infection with the parasite, Toxoplasma gondii. Recurrent posterior uveitis is the typical form of this disease, characterized by unilateral, necrotizing retinitis with secondary choroiditis, occurring adjacent to a pigmented retinochoroidal scar and associated with retinal vasculitis and vitritis. Multiple atypical presentations are also described, and severe inflammation is observed in immunocompromised patients. Histopathological correlations demonstrate focal coagulative retinal necrosis, and early in the course of the disease, this inflammation is based in the inner retina. For typical ocular toxoplasmosis, a diagnosis is easily made on clinical examination. In atypical cases, ocular fluid testing to detect parasite DNA by polymerase chain reaction or to determine intraocular production of specific antibody may be extremely helpful for establishing aetiology. Given the high seroprevalence of toxoplasmosis in most communities, serological testing for T. gondii antibodies is generally not useful. Despite a lack of published evidence for effectiveness of current therapies, most ophthalmologists elect to treat patients with ocular toxoplasmosis that reduces or threatens to impact vision. Classic therapy consists of oral pyrimethamine and sulfadiazine, plus systemic corticosteroid. Substantial toxicity of this drug combination has spurred interest in alternative antimicrobials, as well as local forms of drug delivery. At this time, however, no therapeutic approach is curative of ocular toxoplasmosis.

Cataract surgery in uveitis

Cataract surgery in uveitic eyes is often challenging and can result in intraoperative and postoperative complications. Most uveitic patients enjoy good vision despite potentially sight-threatening complications, including cataract development. In those patients who develop cataracts, successful surgery stems from educated patient selection, careful surgical technique, and aggressive preoperative and postoperative control of inflammation. With improved understanding of the disease processes, pre- and perioperative control of inflammation, modern surgical techniques, availability of biocompatible intraocular lens material and design, surgical experience in performing complicated cataract surgeries, and efficient management of postoperative complications have led to much better outcome. Preoperative factors include proper patient selection and counseling and preoperative control of inflammation. Meticulous and careful cataract surgery in uveitic cataract is essential in optimizing the postoperative outcome. Management of postoperative complications, especially inflammation and glaucoma, earlier rather than later, has also contributed to improved outcomes. This manuscript is review of the existing literature and highlights the management pearls in tackling complicated cataract based on medline search of literature and experience of the authors.

Evaluating exaggerated, prolonged, or delayed postoperative intraocular inflammation

PURPOSE

To provide a diagnostic approach for the evaluation of patients with exaggerated, prolonged, or delayed postoperative intraocular inflammation.

DESIGN

Perspective.

METHODS

Selected articles on normal and abnormal postoperative intraocular inflammation were reviewed and interpreted in the context of the authors' clinical and research experience.

RESULTS

In addition to infectious endophthalmitis, a number of noninfectious conditions characterized by exaggerated, prolonged, or delayed postoperative inflammation have been described. Heuristically, increased postsurgical inflammation may be categorized by time from surgery to first recognition using the following general guidelines: as immediate and occurring within 2 days after surgery; as early and occurring after 2 days, but within the first 2 weeks, after surgery; and as delayed and occurring more than 2 weeks after surgery.

CONCLUSIONS

Although infectious endophthalmitis always must be excluded as a cause of increased postoperative intraocular inflammation, potential noninfectious causes also exist. We review both infectious and noninfectious causes of increased postoperative inflammation and provide a diagnostic framework for evaluating such patients.

Cataract surgery in the setting of uveitis

PURPOSE OF REVIEW

To describe recent evidence from the literature concerning optimal treatment of cataract in patients with concomitant uveitis.

RECENT FINDINGS

Optimal treatment of cataract in the setting of uveitis requires optimal management of uveitis, including appropriate diagnostic workup and scrupulous attention to preoperative preparation, intraoperative technique, and postoperative management. Recent literature suggests high rates of recurrence of certain forms of uveitis (such as ocular toxoplasmosis) after surgery, suggesting that perioperative prophylaxis may be warranted. Placement of intraocular lenses in the setting of certain forms of uveitis, such as juvenile idiopathic arthritis-associated uveitis, remains controversial. Although excellent outcomes can be achieved with many types of intraocular lenses, several recent studies have suggested that the incidence of postoperative complications may be lower in patients receiving acrylic intraocular lenses compared with other materials. Recent long-term outcome studies in cohorts of uveitis patients undergoing cataract surgery suggest very good outcomes in the majority of patients.

SUMMARY

Provided the unique challenges of cataract surgery in the setting of uveitis are recognized and appropriately addressed, excellent visual outcomes can be achieved in most patients.

Cataracts in congenital toxoplasmosis

PURPOSE

To determine the incidence and natural history of cataracts in children with congenital toxoplasmosis.

METHODS

Children referred to the National Collaborative Chicago-based Congenital Toxoplasmosis Study (NCCCTS) between 1981 and 2005 were examined by ophthalmologists at predetermined times according to a specific protocol. The clinical course and treatment of patients who developed cataracts were reviewed.

RESULTS

In the first year of life, 134 of 173 children examined were treated with pyrimethamine, sulfadiazine, and leukovorin, while the remaining 39 were not treated. Cataracts occurred in 27 eyes of 20 patients (11.6%, 95% confidence interval [7.2%, 17.3%]). Fourteen cataracts were present at birth and 13 developed postnatally. Locations of the cataracts included anterior polar (three eyes), anterior subcapsular (six eyes), nuclear (five eyes), posterior subcapsular (seven eyes), and unknown (six eyes). Thirteen cataracts were partial, nine total, and five with unknown complexity. Twelve cataracts remained stable, 12 progressed, and progression was not known for 3. Five of 27 eyes had cataract surgery, with 2 of these developing glaucoma. Sixteen eyes of 11 patients had retinal detachment and cataract. All eyes with cataracts had additional ocular lesions.

CONCLUSIONS

In the NCCCTS cohort, 11.6% of patients were diagnosed with cataracts. There was considerable variability in the presentation, morphology, and progression of the cataracts. Associated intraocular pathology was an important cause of morbidity.

[Reactivation of ocular toxoplasmosis after laser in situ keratomileusis]

Laser in situ keratomileusis (LASIK) is a safe and efficient refractive surgical procedure that provides excellent results in most cases. Several complications have been reported, most of them related to the posterior segment of the eye. Although they are quite rare, a growing number of vitreoretinal pathologic conditions after LASIK have been reported. To date no article has reported an inflammatory or infectious disease of the posterior segment after a LASIK procedure. We report a case of reactivation of toxoplasmic chorioretinitis that occurred 5 days after a LASIK procedure. Clinical outcome was spontaneously favorable after 1 month, with no loss of vision. Although a causal effect between LASIK and toxoplasmic chorioretinitis reactivation cannot be proven with a single case report, we stress the importance of dilated fundus examination in LASIK preoperative assessment: our case suggests that in the presence of preoperative toxoplasmic chorioretinitis scars, increased retinal monitoring is required.

[Recurrent toxoplasmic retinochoroiditis after clindamycin treatment]

PURPOSE

To evaluate the efficacy and safety of subconjunctival injections of clindamycin associated with oral corticotherapy in the treatment of toxoplasmic retinochoroiditis (TRC) and its effect on recurrence.

PATIENTS AND METHODS

This study investigated 21 patients (10 males and 11 females) who presented to an ophthalmological department from 1995 to 2000, aged 14-55 years (mean, 28 years), with unilateral TRC. They were treated with subconjunctival injections of clindamycin and systemic corticotherapy at a dose of 1 mg/kg/day. Clinical follow-up consisted of assessment of visual acuity and biomicroscopic fundus examination, completed by retinal angiography if necessary.

RESULTS

We observed clinical improvement in 68.75% of patients within 4 days and in all patients healing of the chorioretinal area within 1.6 months. During the follow-up period ranging from 6 to 52 months (mean, 22 months), there have been two recurrences (9%) over the first 18 months. Tolerance of the injections was good. Serious side effects were noted in two patients: one case of conjunctival necrosis and one case of corneal and conjunctival erosion.

CONCLUSION

In treating ocular toxoplasmosis, clindamycin appears to be a safe and effective substitute for the classic protocol (pyrimethamine-sulfadiazine, pyrimethamine-azithromycin), for which a 50% recurrence rate has been reported. It provides relatively good protection against recurrence and warrants testing in further controlled studies.

Reactivation of Ocular Toxoplasmosis After LASIK

PURPOSE

To report a reactivation of ocular toxoplasmosis after LASIK.

METHODS

Case report of a 34-year-old man who underwent bilateral LASIK. The posterior segment examination revealed an old toxoplasmosis scar in the retinal periphery of the right eye.

RESULTS

Uncorrected visual acuity improved postoperatively, and the patient was satisfied. However, 52 days after the procedure, he complained of loss of visual acuity in his right eye. Examination revealed signs of anterior uveitis, vitreitis, and active chorioretinal lesion satellite of the old toxoplasmosis scar. The patient was treated with a multidrug regiment with resolution of the vitreous and lesion activity.

CONCLUSIONS

Toxoplasmosis reactivation may develop after LASIK.

Use of PCR to diagnose Toxoplasma gondii chorioretinitis in eyes with severe vitritis

Two cases are reported of intraocular inflammation in which severe vitritis hampered the fundal view, making an accurate clinical diagnosis impossible, and vitreous analysis using conventional techniques was unhelpful. PCR for Toxoplasma gondii was positive in both cases and provided the only way of confirming the diagnosis. Other ocular samples also underwent PCR for Toxoplasma DNA and the specificity of this approach is demonstrated.

Morphological plasticity varies with duration of infection: evidence from lactating and virgin wild-derived house mice (Mus musculus) infected with an intestinal parasite (Heligmosomoides polygyrus; Nematoda)

With chronic parasite infection, host response to the parasite may change throughout the duration of the infection as the host progresses from the acute to the chronic phase. We investigated the effects of parasite infection ranging in duration from 30 to 120 days on host morphology both alone and in combination with lactation by using captive wild-derived house mice (Mus musculus) experimentally infected with a naturally occurring intestinal nematode (Heligmosomoides polygyrus). We found that some changes in host morphology were greatest at 30-60 days post-infection (e.g. spleen mass) followed by a decline towards the control state whereas other morphological changes were greatest at 90-120 days post-infection (e.g. small intestine mass) after a relatively steady increase with infection duration. For all infection durations, the morphological responses to parasite infection were similar for virgin and lactating mice (except for lean body mass). After accounting for changes in body mass with lactation, lactating mice increased organs of the gastrointestinal tract as well as liver and kidney but had less body fat than virgin mice. This is the first study to demonstrate that morphological plasticity of mice parasitized by H. polygyrus varies with infection duration and that this variation is generally similar for lactating and virgin mice.

Ocular manifestations of toxoplasmosis

PURPOSE OF REVIEW

The concepts of toxoplasmosis and its ocular manifestations in humans have thoroughly changed in the past 3 years. This review addresses new epidemiologic data, specifically the occurrence of ocular disease in postnatal infections, and puts the changed views on the frequency and pathogenesis of toxoplasmic ocular manifestations into historical perspective.

RECENT FINDINGS

Newly described clinical presentations are discussed together with their recent diagnostic possibilities. The new data on congenital or postnatal acquisition of infection and their importance for ocular involvement are presented as well as the high prevalence of 79% of recurrent disease in ocular toxoplasmosis, which cannot be prevented by short-term treatments. Recently published analyses of literature showed, unexpectedly, the lack of efficacy of short-term treatments for ocular disease as well as of the long-term prenatal treatments on fetal transmission rate and the severity of congenital disease.

SUMMARY

The recent guidelines for treatment are included together with the up-to-date recommendations for the treatment of ocular toxoplasmosis in the immunosuppressed host.

Ocular toxoplasmosis: a global reassessment. Part I: epidemiology and course of disease

PURPOSE

To update clinical information about ocular toxoplasmosis. Part I reviews information about prevalence of disease, sources of infection, relation of ocular disease to time of Toxoplasma gondii infection (congenital vs. postnatally acquired), and course of disease.

DESIGN

Literature review.

METHODS

Selected articles from the medical literature, information from recent scientific meetings, and the author's personal experiences were reviewed critically in preparation for the LX Edward Jackson Memorial Lecture.

RESULTS

The prevalence of T. gondii infection varies geographically and increases with age; in the United States, the overall proportion is 22.5%. The proportion of infected individuals in the United States who have had episodes of ocular toxoplasmosis is unknown, but may be approximately 2%. Prevalence of ocular involvement is substantially greater in other parts of the world, including southern Brazil. In addition to undercooked meat and unwashed vegetables, drinking water contaminated with oocysts may be an important source of infection in some settings. In contrast to traditional teaching, evidence suggests that most individuals with ocular toxoplasmosis were infected postnatally. Ocular lesions may first develop many years after T. gondii infection. The risk of recurrent ocular disease appears to be greater during the first year after an episode of toxoplasmic retinochoroiditis than during subsequent years.

CONCLUSIONS

Reassessment of older publications in the light of recent observations provides a richer understanding of ocular toxoplasmosis, although knowledge about the disease remains incomplete. A better understanding of the clinical characteristics and course of ocular toxoplasmosis will have important implications for developing more effective prevention and treatment strategies.

Management of coincident cataract and uveitis

Cataract surgery in a patient with uveitis is more complex than senile cataract extraction, because it involves multiple considerations related to the cause of uveitis, prospects of visual rehabilitation, appropriate surgical timing and technique, and the type and material of the intraocular lens used. Establishing the diagnosis, thorough eye examination, careful patient selection and meticulous control of perioperative inflammation are key elements to a successful visual outcome. Our aims in this article are to review the literature on this subject over the past year and highlight the behavior of intraocular lenses of various biomaterials in the uveitic eye. In addition, we also reemphasize the idea of a model of zero tolerance to intraocular inflammation to minimize the incidence of irreversible damage to ocular structures essential to good vision.