Polymerase chain reaction in the diagnosis of uveitis

Polymerase chain reaction confirmed mycobacterium tuberculosis intermediate uveitis - analysis of 22 eyes of 14 cases from a tertiary care centre in South India: a retrospective study

Background

To report the role of Polymerase Chain Reaction in confirming the diagnosis of presumed Mycobacterium Tuberculosis (MTB) Intermediate Uveitis.

Method

Retrospective analysis of 22 eyes of 14 cases of presumed tubercular intermediate uveitis wherein intraocular fluid was tested for MTB DNA by Nested & Real-time PCR, based on clinical suspicion of tubercular aetiology. QuantiFERON TB gold test and High-Resolution CT Chest were done. Patients were treated with anti-tubercular therapy with oral steroids & immunomodulators. In the study, eleven were male (79%) and three female (21%). The median age was 34 years. Nested PCR for both IS 6110 & MPB 64 was positive in 64% of the cases, IS 6110 positive in 23% and MPB 64 positive in 15%. Real-time PCR was positive in 48% of the cases. Vision improved in 33% of cases, maintained in 57%, and worsened in 10% of cases.

Conclusion

Presumed Tubercular intermediate uveitis can be confirmed by PCR of intraocular fluids. Anti-tubercular therapy with immunosuppression can improve vision and prevent recurrences in such cases.

An imaging-based treatment algorithm for posterior focal retinitis

Background:

In this paper, our aim was to describe an imaging-based empirical approach for categorizing and initiating treatment of immunocompetent patients with posterior focal retinitis, prior to the availability of results of expensive laboratory investigations.

Materials and methods:

The hospital records of 13 patients with posterior focal retinitis were reviewed.

Results:

Of the 13 patients, 9 were women and 4 were men. The mean age was 24 ± 8 years. Based on similarities in clinical presentation and imaging, we categorized our cases into three groups with different first-line therapeutic strategies. In the first group, patients had presumed toxoplasmosis (treated with oral cotrimoxazole); in the second group, patients had presumed viral (herpetic) etiology (treated with oral valacyclovir); and in the third group, patients had presumed nonherpetic, nontoxoplasma retinitis (treated with oral doxycycline). Positive serology results included Rickettsia (two patients), Borrelia (one patient), Toxoplasma (two patients), and herpes simplex virus (one patient).

Conclusion:

An empirical approach for early initiation of therapy in retinitis cases based on imaging features is described.

devR PCR for the diagnosis of intraocular tuberculosis

PURPOSE

To compare the efficacy of devR and MPB64 PCR in the diagnosis of intraocular tuberculosis.

METHODS

Prospective, nonrandomized study. Seventy-five patients were enrolled in 3 groups. Group A had 25 patients with presumed intraocular tubercular uveitis, group B had 25 controls with specific uveitis other than tubercular uveitis, and group C included 25 non-uveitic negative controls. The undiluted vitreous/aqueous samples were collected and subjected to PCR assay for devR and MPB64 gene sequence of Mycobacterium tuberculosis (MTB) to detect sensitivity and specificity.

RESULTS

devR PCR was positive in 16 (64%) out of 25 patients with presumed tubercular uveitis. MPB64 PCR was positive in 18 (72%) out of 25 patients with presumed tubercular uveitis. The sensitivity and specificity of devR were 64 and 100%, respectively. The sensitivity and specificity of MPB64 PCR were 72 and 100%, respectively.

CONCLUSION

devR PCR is not a better tool than MPB64 PCR for diagnosing intraocular tuberculosis.

The impact of cataract surgery on AMD development and progression

Age-related macular degeneration (AMD) and cataract are two leading causes of visual impairment worldwide which often occur concurrently in the same patient. With more than 1.6 million cataract operations performed per year in the United States, many of which occur in the nearly 1.75 million individuals diagnosed with AMD, there is ample incentive to further explore the interaction between these two conditions. Notably, the role of cataract surgery on AMD development and progression is of particular interest. This review summarizes the major findings from literature focusing on the effect of cataract surgery on AMD.

Macrophage polarization in the maculae of age-related macular degeneration: a pilot study

Macrophages can be polarized to exhibit either pro-inflammatory M1 or pro-angiogenic M2 phenotypes, but have high phenotypic plasticity. This pilot study investigated macrophage polarization in the macular retina and choroid of age-related macular degeneration (AMD) and non-AMD subjects, as well as in AMD choroidal neovascular membranes (CNVM). All specimens were evaluated for routine histopathology. Quantitative real-time polymerase chain reaction for representative M1 (CXCL11) and M2 (CCL22) transcripts were performed on macular choroidal trephines (MCT) of 19 AMD and nine non-AMD eye bank eyes, on the microdissected macular retinal cells from the archived slides of five geographic atrophic AMD, five exudative/neovascular AMD, and eight normal autopsied eyes, and on microdissected inflammatory cells from two surgically removed CNVM that did not respond to anti-vascular endothelial growth factor (VEGF) therapy. High M2-chemokine transcript and a low ratio of M1 to M2 chemokine transcript were found in aging non-AMD MCT. Advanced AMD maculae had a higher M1 to M2 chemokine transcript ratio compared to normal autopsied eyes. Macrophages in the two CNVM of patients unresponsive to anti-VEGF therapy were polarized toward either M1 or M2 phenotypes. The number of M2 macrophages was increased compared to M1 macrophages in normal aging eyes. A pathological shift of macrophage polarization may play a potential role in AMD pathogenesis.

Recent studies provide an updated clinical perspective on blue light-filtering IOLs

Background

Recent reviews of blue light-filtering intraocular lenses (IOLs) have stated their potential risks for scotopic vision and circadian photoentrainment. Some authors have challenged the rationale for retinal photoprotection that these IOLs might provide. Our objective is to address these issues by providing an updated clinical perspective based on the results of the most recent studies.

Methods

This article evaluates the currently available published papers assessing the potential risks and benefits of blue light-filtering IOLs. It summarizes the results of seven clinical and two computational studies on photoreception, and several studies related to retinal photoprotection, all of which were not available in the previous reviews. These results provide a clinical risk/benefit analysis for an updated review for these IOLs.

Results

Most clinical studies comparing IOLs with and without the blue light-filtering feature have found no difference in clinical performance for; visual acuity, contrast sensitivity, color vision, or glare. For blue light-filtering IOLs, three comparative clinical studies have shown improved contrast sensitivity and glare reduction; but one study, while it showed satisfactory overall color perception, demonstrated some compromise in mesopic comparative blue color discrimination. Comparative results of two recent clinical studies have also shown improved performance for simulated driving under glare conditions and reduced glare disability, better heterochromatic contrast threshold, and faster recovery from photostress for blue light-filtering IOLs. Two computational and five clinical studies found no difference in performance between IOLs with or without blue light-filtration for scotopic vision performance and photo entrainment of the circadian rhythm. The rationale for protection of the pseudophakic retina against phototoxicity is discussed with supporting results of the most recent computational, in-vitro, animal, clinical, and epidemiological investigations.

Conclusions

This analysis provides an updated clinical perspective which suggests the selection of blue light-filtering IOLs for patients of any age, but especially for pediatric and presbyopic lens exchange patients with a longer pseudophakic life. Without clinically substantiated potential risks, these patients should experience the benefit of overall better quality of vision, reduced glare disability at least in some conditions, and better protection against retinal phototoxicity and its associated potential risk for AMD.

Electronic supplementary material

The online version of this article (doi:10.1007/s00417-011-1697-6) contains supplementary material, which is available to authorized users.

Diagnosis of tubercular uveitis by quantitative polymerase chain reaction

Purpose

To report the use of real-time or quantitative polymerase chain reaction (qPCR) in confirming the diagnosis of tubercular uveitis.

Methods

A qPCR assay using primers targeting the MPB64 gene of Mycobacterium tuberculosis (MTB) was developed. A standard curve for quantification of mycobacterial load was generated. Vitreous fluid samples from patients presumed to have tubercular uveitis were assayed to identify and quantify the mycobacterial load. The amount of the test sample product was interpolated from the standard curve of cycle threshold values generated from known starting copy number of standard MTB DNA.

Results

The copies of MTB genomes in the three test samples studied were found to be 7.61 × 10⁴, 4.53 × 10⁴, and 1.43 × 10⁵, respectively.

Conclusion

qPCR detected and quantified MTB genome from the vitreous fluid of eyes clinically suspected with tubercular uveitis.

Multifocal posterior necrotizing retinitis

PURPOSE

To describe the clinical features of an acute, inflammatory, and progressive retinal necrosis that affects primarily the posterior pole.

DESIGN

Retrospective, interventional case series.

METHODS

Twenty-seven eyes of 24 patients diagnosed with and treated for acute retinal necrosis (ARN) were categorized into two groups according to the predominant location of retinitis at presentation: either in the peripheral retina or in the posterior pole. Clinical features, disease progression, visual outcomes, and complications of these two groups were compared.

RESULTS

Fifteen eyes demonstrated the known peripheral retinitis pattern, and 12 eyes exhibited a pattern of retinitis that affected mainly the posterior pole. Eyes with peripheral retinitis showed focal, well-demarcated areas of retinal necrosis in the periphery with rapid circumferential progression and rare involvement of the posterior pole. All eyes with posterior pole retinitis had multifocal deep lesions posterior to the vortex veins at presentation, and half of these eyes had lesions in the macula. These lesions progressed to patches of confluent retinitis in both the periphery and the posterior pole. There was no significant difference between the two groups in the incidence of anterior chamber and vitreous cells, vascular sheathing, retinal hemorrhages, or optic disk edema. Patients with posterior retinitis involvement seemed to have a worse visual outcome during the first two years after diagnosis. The Cox proportional hazards model suggested a higher incidence of retinal detachment in patients with posterior retinitis (P = .07).

CONCLUSIONS

The authors report a pattern of herpetic retinitis that affects predominantly the posterior pole and may have a worse visual prognosis and a higher rate of retinal detachment.