Carlos Alexandre de Amorim Garcia

Socioeconomic conditions as determining factors in the prevalence of systemic and ocular toxoplasmosis in Northeastern Brazil

OBJECTIVE To determine the prevalence of systemic and ocular toxoplasmosis among 1024 students in the city of Natal, Northeastern Brazil, and correlate it with demographic, socioeconomic and epidemiological risk factors. METHODS The study population was randomly selected, asked to fill out a questionnaire, provide a blood sample for IgG and IgM (MEIA) serology and a hemogram, and undergo an eye examination. RESULTS The seroprevalence for IgG was 46% (95% CI = 42.9-49.2%) and that for IgM was 1.4% (95% CI = 0.8-2.4%). The prevalence of ocular lesions was 1.15% (95% CI = 0.6-2.0%). In the univariate analyses, confirmed by multivariate analysis, the socioeconomic conditions were determinants in the prevalence of systemic and ocular toxoplasmosis (mothers schooling = literacy/OR = 2.9 and p < 0.001). CONCLUSIONS The prevalence of systemic toxoplasmosis, although high, was lower than that found in studies performed in the South and Southeast of Brazil, and the incidence of ocular lesions was totally different, being lower by a factor varying from 5 to 17. Although important epidemiological variables, such as owning a cat, drinking unfiltered water or having had contact with lakes or rivers, were found to be correlated with toxoplasmosis in the preliminary analysis, they lost their influence when included in the logistic model. However, further studies must be undertaken to identify the reasons for these findings, including the determination of the strains of Toxoplasma gondii encountered in different regions of the country and the sources of the water utilized by these populations.

Clinical Features of 121 Patients With Diffuse Unilateral Subacute Neuroretinitis

PURPOSE To describe the determinant clinical signs to diagnose diffuse unilateral subacute neuroretinitis (DUSN) and the main features related to identification of the live worm. DESIGN Retrospective study performed at the Federal University of Rio Grande do Norte, Rio Grande do Norte, Brazil, between 2003 and 2008. METHODS Patients with early- or late-stage diffuse unilateral subacute neuroretinitis were included. All patients underwent complete ophthalmologic examination and had a minimum of 6 months of follow-up. RESULTS A total of 121 patients were included. Most patients were younger than 20 years (69.42%). Visual acuity was 20/400 or worse in 86 patients (71.7%). Nine patients (7.43%) presented in the early stage and 112 (92.57%) patients presented in the late stage. Subretinal tracks (91.7%), focal alterations of the retinal pigment epithelium (89.3%), small white spots (80.2%), and optic nerve atrophy (76.9%) were the most frequent clinical features. The subretinal worm was identified in 48 patients (39.66%), and laser treatment to destroy it was performed in all cases. The most common location of the nematode was the posterior pole (21 patients). It was observed that the younger the age, the higher the indices of larvae identification (P=.022). Multifocal yellow-white lesions and vitritis were correlated with identification of the worm (P=.001). Mean logarithm of the minimal angle of resolution visual acuity was 1.466 (20/600) and 1.281 (20/400) before and after laser treatment, respectively (P<.005). CONCLUSIONS Identification of clinical signs and diagnosis of diffuse unilateral subacute neuroretinitis in its early stage, followed by prompt location and destruction of the worm by photocoagulation, may improve the vision of affected patients.

Optic coherence tomography in a patient with diffuse unilateral subacute neuroretinitis

PURPOSE To measure retinal nervous fiber layer (RNFL) thickness using OCT3 (Carl-Zeiss) in patients with diffuse unilateral subacute neuroretinitis (DUSN) with or without live worm and correlate it with visual acuity. METHODS RNFL thickness, using RNFL thickness 3.4 program and best corrected visual acuity were measured in patients with DUSN between January 2005 and December 2006. RESULTS Thirty-eight patients, aged 9 - 42 years were selected, of whom 20 had live worm. Mean RNFL was 71.55 +/- 27.26 in the DUSN eye and 103.07 +/- 20.66 in the contralateral eye (p<0.001). Pearsons correlation between visual acuity and RNFL was r= -0.522 (p<0.001) in the DUSN eye and r= -0.097 (p=0.509) in the contralateral eye. CONCLUSION RNFL thickness in DUSN patients is directly proportional to visual acuity. Further research is needed to reinforce the correlation between visual acuity and thickness of the nerve fibers in patients with DUSN to follow them after the treatment.

Prevalence of refractive errors in students in Northeastern Brazil

PURPOSE To determine the prevalence of refractive errors in the public and private school system in the city of Natal, Northeastern Brazil. METHODS Refractometry was performed on both eyes of 1,024 randomly selected students, enrolled in the 2001 school year and the data were evaluated by the SPSS Data Editor 10.0. Ametropia was divided into: 1- from 0.1 to 0.99 diopter (D); 2- 1.0 to 2.99 D; 3- 3.00 to 5.99 D and 4- 6D or greater. Astigmatism was regrouped in: I- with-the-rule (axis from 0 to 30 and 150 to 180 degrees), II- against-the-rule (axis between 60 and 120 degrees) and III- oblique (axis between > 30 and < 60 and >120 and <150 degrees). The age groups were categorized as follows, in: 1- 5 to 10 years, 2- 11 to 15 years, 3- 16 to 20 years, 4- over 21 years. RESULTS Among refractive errors, hyperopia was the most common with 71%, followed by astigmatism (34%) and myopia (13.3%). Of the students with myopia and hyperopia, 48.5% and 34.1% had astigmatism, respectively. With respect to diopters, 58.1% of myopic students were in group 1, and 39% distributed between groups 2 and 3. Hyperopia were mostly found in group 1 (61.7%) as well as astigmatism (70.6%). The association of the astigmatism axes of both eyes showed 92.5% with axis with-the-rule in both eyes, while the percentage for those with axis against-the-rule was 82.1% and even lower for the oblique axis (50%). CONCLUSION The results found differed from those of most international studies, mainly from the Orient, which pointed to myopia as the most common refractive error, and corroborates the national ones, with the majority being hyperopia.

Diffuse Unilateral Subacute Neuroretinitis (DUSN)

Diffuse unilateral subacute neuroretinitis (DUSN) is an ocular infectious disease caused by one of 2 different sized and as of yet unidentified nematodes capable of infiltrating the subretinal space. It occurs mainly in children and young adults and the clinical course is characterized by periods of activity and remission. The intraocular inflammation tends to be diffuse and in the acute phase is accompanied by swelling of the optic disc, focal retinitis, and choroiditis. In the chronic phase, optic nerve atrophy occurs if the nematode is not destroyed.

Epidemiologic study of anisometropia in students of Natal, Brazil

PURPOSE To perform an epidemiologic study in students in Natal/Brazil, with relation to refractional anisometropia, evaluating criteria such as: gender, age, and association with strabismus and amblyopia. METHODS A study of 1,024 students randomly selected from several districts of Natal/Brazil was undertaken by the Department of Ophthalmology of the Federal University of Rio Grande do Norte (UFRN), observing the following criteria of > or =2 spherical or cylindrical diopter refractional anisometropia relating it to sex, age, association with strabismus, amblyopia and anisometropia classification. RESULTS We found a prevalence of 2% (N=21) anisometropia in the students. The female gender predominated with 81% (N=17). In students with anisometropia, we observed an association with strabismus in 9.5% of cases (N=2), both with exotropia. The association of anisometropia with amblyopia occurred in 47.6% of the cases (N=10), with 8 cases of unilateral amblyopia and 2 cases of bilateral amblyopia. CONCLUSIONS There was a predominance of anisometropia in females, and an increased prevalence of strabismus and amblyopia in students with anisometropia.

Spectral Domain Optical Coherence Tomography in Diffuse Unilateral Subacute Neuroretinitis

Purpose. To describe the SD-OCT findings in patients with diffuse unilateral subacute neuroretinitis (DUSN) and evaluate CRT and RNFL thickness. Methods. Patients with clinical diagnosis of DUSN who were submitted to SD-OCT were included in the study. Complete ophthalmologic examination and SD-OCT were performed. Cirrus scan strategy protocols used were 200 × 200 macular cube, optic nerve head cube, and HD-5 line raster. Results. Eight patients with DUSN were included. Mean RNFL thickness was 80.25 μm and 104.75 μm for affected and normal eyes, respectively. Late stage had mean RNFL thickness of 74.83 μm compared to 96.5 μm in early stage. Mean CMT was 205.5 μm for affected eyes and 255.13 μm for normal fellow eyes. Conclusion. RNFL and CMT were thinner in DUSN eyes compared to normal eyes. Late-stage disease had more pronounced thinning compared to early-stage patients. This thinning in RNFL and CMT may reflect the low visual acuity in patients with DUSN.

Diffuse unilateral subacute neuroretinitis.

Diffuse unilateral subacute neuroretinitis (DUSN) is a usually unilateral inflammatory disease characterized by an insidious, usually severe loss of peripheral and central vision. Clinical characteristics are manifested in early and late stages. Parasites of different sizes and several species of nematodes have been reported as the etiology of DUSN without conclusive evidence about the specific agent. Because serologic testing has been variable, the definitive diagnosis is made when the clinical characteristics of DUSN are found in conjunction with an intraocular worm. Laser photocoagulation, pars plana vitrectomy, thiabendazole, and albendazole have been used to treat DUSN with variable success.

Intermediate uveitis complicated by choroidal granuloma following subretinal neovascular membrane: case reports

Choroidal neovascularization is a very rare complication in intermediate uveitis. A 27-year-old female patient diagnosed with intermediate uveitis two years ago. She presented with 20/200 visual acuity, snowballs, snowbanks, and macular cystoid edema in the right eye observed by fluorescein and optical coherence tomography (OCT). Photocoagulation was performed in the inferior peripheral retina in both eyes. The patient refused to undergo the prescribed clinical treatment. She returned twelve months later presenting with count fingers visual acuity, dry retina and subretinal macular pigmented granuloma observed on OCT. A 15-year-old female patient with decreased visual acuity of 20/400 in the right eye for eight days. She presented with bilateral vasculitis and papilitis, in the right eye, hemorrhage and extramacular subretinal neovascular membrane were observed on fluorescein and OCT. She was treated with 40 mg prednisone and intravitreous injection of 1.25 mg bevacizumab. Five months later she presented with 20/50 visual acuity, and extramacular granuloma observed on OCT. The formation of subretinal granuloma in intermediate uveitis is a possibility when complicated by subretinal neovascular membrane.

Prevalence of strabismus among students in Natal/RN - Brazil

PURPOSE: To estimate the prevalence of strabismus in Natal, Brazil, among elementary and high school students of the public and private educational systems, in addition to detecting etiological factors. METHODS: 1024 students were randomly selected and submitted to a questionnaire and a complete ophthalmologic examination, by professors and resident physicians in Ophthalmology at the Federal University of Rio Grande do Norte. RESULTS: Of 1024 students, 1015 were examined; 29 were found to have strabismus (2.9%), 20 of whom had manifest exotropia (2%), 2 had intermittent exotropia (0.2%), 6 had esotropia (0.6%) and 1 had V anisotropies (0.1%). CONCLUSIONS: The strabismus prevalence of the student population of Natal falls within the range of the worldwide population. There was ocular lesion in only one student (retinochoroiditis scar on the posterior pole in both eyes) related to strabismus.