Elevation of laser flare photometry in patients with cytomegalovirus retinitis and AIDS

Clinical features of Cytomegalovirus retinitis in patients with acquired immunodeficiency syndrome and efficacy of the current therapy

Background

Cytomegalovirus retinitis (CMVR) is the most common and sight-threatening opportunistic retinal infection in patients with acquired immunodeficiency syndrome (AIDS) and several controversies remain to be settled. We aimed to summarize the current evidence and clarify the clinical features and prognosis of CMVR in AIDS patients.

Methods

The databases PubMed, EMBASE, and Ovid from inception to April 2022 were searched to identify the relevant studies. R software version 3.6.3 was used to perform the statistical analyses. Results in proportion with 95% confidence interval (CI) were calculated using the Freeman-Tukey variant of arcsine square transformation.

Results

We finally included 236 studies comprising 20,214 patients. CMVR in AIDS was male-dominated (88%, 95%CI 86%-89%), with 57% (95%CI 55%-60%) aged <41 years and 44% (95%CI 41%-47%) being bilaterally involved. CMVR was preponderant in AIDS patients with the following characteristics: white and non-Hispanic, homosexual, HIV RNA load ≥ 400 copies/mL, and CD4+ T-cells <50 cells/μL. The positivity of CMV-DNA in blood, aqueous humor, and vitreous humor was 66% (95%CI 52%-79%), 87% (95%CI 76%-96%), and 95% (95%CI 85%-100%), respectively. The most common symptoms were blurred vision (55%, 95%CI 46%-65%), followed by asymptomatic, visual field defect, and floaters. CMVR was first diagnosed and regarded as the clue to AIDS diagnosis in 9% (95%CI 6%-13%) of CMVR patients. Approximately 85% (95%CI 76%-93%) of the CMVR patients have received cART. CMVR remission was observed in 72%-92% of patients depending on the specific category of anti-CMV therapy. The general incidence of CMVR-related RD in the entire course was 24% (95%CI 18%-29%), of which most patients received PPV with SO or gas tamponade and the rate of anatomic success was 89% (95%CI 85%-93%).

Conclusion

CMVR is a common opportunistic infection with diverse clinical features in AIDS patients, preponderant in those who are male, homosexual, or with CD4+ T-cells <50 cells/μL. Current therapies for CMVR and CMVR-related RD were shown to be effective. Early detection and routine ophthalmic screening should be promoted in AIDS patients.

Systematic review registration

PROSPERO, identifier CRD42022363105.

Advances and potential new developments in imaging techniques for posterior uveitis. Part 1: noninvasive imaging methods

The aim of this review was to identify the imaging methods at our disposal to optimally manage posterior uveitis at the present time. The focus was put on methods that have become available since the 1990s, some 30 years after fluorescein angiography had revolutionized imaging of posterior uveitis in particular imaging of the retinal vascular structures in the 1960s. We have focussed our review on precise imaging methods that have been standardized and validated and can be used universally thanks to commercially produced and available instruments for the diagnosis and follow-up of posterior uveitis. The first part of this imaging review will deal with noninvasive imaging methods, focusing on fundus autofluorescence and optical coherence tomography as well as recent developments in imaging of the posterior segment.

Laser flare-cell photometer: principle and significance in clinical and basic ophthalmology

A slit-lamp examination is an indispensable and essential clinical evaluation method in ophthalmology, but, it is qualitative subjective. To complement its weaknesses in making a quantitative evaluation of flare intensity and number of cells in the aqueous humor in the eye, we invented the laser flare-cell photometer in 1988. The instrument enables a non-invasive quantitative evaluation of flare intensity and number of cells in the aqueous with good accuracy and repeatability as well as maneuverability equal to slit-lamp microscopy. The instrument can elucidate the pathophysiology in the blood-aqueous barrier (BAB) function in a variety of ocular disorders. The accuracy of the instrument makes it possible to investigate not only the pathophysiology of intraocular disorders but also the effects of various drugs and surgical procedures in BAB. The instrument does not only lighten the burden on patients in clinical examinations and study but it also helps minimize the sacrifice of experimental animals and improves the reliability of the results by minimizing inter-individual variations through its good repeatability. Here I shall relate how the instrument has been applied to clinical and basic studies in ophthalmology and what novel knowledge its application contributed to pathophysiology in ophthalmology.

Aqueous flare and choroidal thickness in patients with chronic hepatitis C virus infection: a pilot study

PURPOSE

To investigate the status of the blood-aqueous barrier and to evaluate the subfoveal choroidal thickness (SCT) in patients with asymptomatic untreated chronic hepatitis C virus (HCV) infection without any anterior or posterior ocular involvement and to search for possible correlations.

DESIGN

Observational case-control study.

PARTICIPANTS AND CONTROLS

A total of 80 eyes of 20 HCV-positive patients (male-to-female ratio, 12:8; mean age, 46.9±7.23 years) and 20 healthy controls (male-to-female ratio, 10:10; mean age, 48.2±8.71 years) were examined.

METHODS

Participants underwent a complete ophthalmologic examination. Aqueous flare was quantified objectively by using the noninvasive laser flare cell meter FC-500 (Kowa Company Ltd, Tokyo, Japan), whereas SCT was evaluated by using enhanced depth imaging optical coherence tomography (Spectralis OCT; Heidelberg Engineering GmbH, Heidelberg, Germany). A Wilcoxon rank-sum test was performed to compare ocular findings between HCV patients and controls, and correlations were assessed by using the Spearman rank test.

MAIN OUTCOME MEASURES

Retinal and choroidal thickness and anterior chamber inflammation of HCV patients and healthy controls.

RESULTS

Patients with HCV showed significantly higher aqueous flare values (8.37±2.25 photon counts/ms vs. 4.56±1.45 photon counts/ms; P<0.0001) and a significantly increased SCT (362.7±46.5 μm vs. 320.25±32.82 μm; P<0.0001) than healthy controls. Moreover, subjects with liver fibrosis had higher flare values than those with no significant hepatic fibrosis (9.62±1.99 photon counts/ms vs. 6.97±2.19 photon counts/ms; P = 0.0003) and thicker choroids (379.15±44.75 μm vs. 346.3±43.27 μm; P = 0.024). Statistical analysis revealed that there was a positive correlation between aqueous flare values and SCT in HCV patients (r = 0.69; P<0.0001) and between flare and the degree of liver fibrosis (r = 0.67; P = 0.0001).

CONCLUSIONS

This study showed that impairment of the blood-aqueous barrier and thickened choroids are features of asymptomatic HCV patients, and that choroidal thickness increases as the degree of subclinical inflammation of the anterior chamber increases. Patients with significant liver fibrosis have the highest flare values and the thickest choroids.

Cystoid macular edema as a result of immune-recovery uveitis

BACKGROUND

Potent antiretroviral therapy can lead to improved immunity in patients with acquired immune deficiency syndrome. However, ocular inflammation can occur in predisposed individuals. This inflammation is referred to as immune-recovery uveitis. Cystoid macular edema (CME) is a complication that can result from this inflammation and is emerging as a major cause of visual loss in human immunodeficiency virus (HIV)-infected patients.

CASE REPORT

A 52-year-old man presented with complaints of intermittent decreased vision that had coincided with the initiation of antiviral treatment. He also reported metamorphopsia and floaters in both eyes of several years duration. He had a history of HIV for 20 years and was only recently started on Highly Active Antiretroviral Therapy (HAART). He reported a vague history of ocular problems involving his retina. Retinal examination revealed bilateral areas of peripheral scarring from presumed past ocular inflammation and thickening and irregularity at each macula. Ancillary testing was performed, and CME was diagnosed.

CONCLUSIONS

Immune-recovery uveitis is a leading cause of visual disturbance in HIV-infected patients with a history of cytomegalovirus (CMV) retinitis on HAART. Although the immune recovery associated with the advent of HAART has decreased the need for potent CMV medications, the heightened immune response can be associated with sight-threatening inflammation.

Vitreal pharmacokinetics of peptide-transporter-targeted prodrugs of ganciclovir in conscious animals

PURPOSE

To delineate the vitreal pharmacokinetics of dipeptide monoester prodrugs of ganciclovir (GCV) with conscious rabbit model using ocular microdialysis and to compare with published results from anesthetized model.

METHODS

New Zealand albino male rabbit was selected as the animal model. Conscious animal ocular microdialysis technique with permanently implanted probes was employed to delineate the pharmacokinetics of GCV, L-valine-GCV (Val-GCV), and dipeptide monoester GCV prodrugs [val-val and L-glycine-val (Gly-Val)] after intravitreal administration.

RESULTS

This work employs conscious model to evaluate vitreal pharmacokinetic parameters and compares the results with previously published data from anesthetized animal, thereby demonstrating the effect of anesthesia on the vitreal disposition of dipeptide prodrugs of GCV. Results have revealed that area under curve (AUC), clearance, and last measured plasma concentration (C(last)) for all 4 compounds were significantly altered in a conscious animal relative to the anesthetized model, while mean residence time (MRT) was significantly reduced. However, the AUCs of regenerated Val-GCV and GCV from Gly-Val-GCV and Val-Val-GCV were found to be unchanged, suggesting higher ocular metabolism in conscious animals.

CONCLUSION

This study for the first time delineates the vitreal pharmacokinetics of a GCV prodrug in conscious animals and compares the data with anesthetized animals. Lower vitreal exposure levels were obtained in case of conscious animal model; however, the elimination rates were not influenced by anesthesia.

Vitreal pharmacokinetics of biotinylated ganciclovir: role of sodium-dependent multivitamin transporter expressed on retina

PURPOSE

The objective of this study was to investigate the role of sodium-dependent multiple vitamin transporter (SMVT) on Biotin-Ganciclovir (biotin-GCV) uptake on both human retinal pigmented epithelium cell line (ARPE-19) and rabbit retina. Study also aims to delineate the vitreal pharmacokinetics of biotin-GCV.

METHOD

ARPE-19 was employed to study the in vitro uptake experiments. New Zealand white albino rabbits were used to study in vivo retinal uptake and vitreal pharmacokinetics following intravitreal administration of biotin-GCV. In vitro uptake kinetics of [3H] biotin was determined at various initial concentrations. Competitive inhibition studies were conducted in the presence of unlabelled biotin, desthiobiotin, pantothenic acid, and lipoic acid. Various other uptake studies were performed to functionally characterize the transporter. To provide the molecular evidence of this transporter, Reverse Transcription-Polymerase Chain Reaction (RT-PCR) studies were also conducted. In vivo retinal/choroidal uptake studies were carried out with New Zealand albino rabbits. Unconscious animal ocular microdialysis studies were performed in order to evaluate intravitreal pharmacokinetics of GCV and Biotin-GCV.

RESULTS

Uptake of [3H] biotin into ARPE-19 was linear over 7 min, and found to be saturable with K(m) of 138.25 muM and Vmax of 38.85 pmol/min/mg protein. Both pantothenic acid and lipoic acid decreased significantly in uptake of biotin in the concentration-dependent manner. Uptake of biotin into ARPE-19 was found to be temperature, energy, and Na+ dependent but Cl(-)independent. Further, RT-PCR studies identified a band exhibiting presence of hSMVT on ARPE-19. Biotin-GCV is recognized by SMVT system present on the ARPE-19 and rabbit retina. Vitreal Pharmacokinetics profile reveals that most of the parameters were not significantly different for GCV and Biotin-GCV. However, use of Biotin-GCV may result in sustain levels of regenerated GCV in vitreous.

CONCLUSIONS

SMVT was identified and functionally characterized on ARPE-19 cells. Further, Biotin-GCV shares this transport system. Vitreal pharmacokinetics of the conjugate was determined in unconscious rabbit model.

Intraocular inflammation associated with ocular toxoplasmosis: relationships at initial examination

PURPOSE

To describe characteristics of intraocular inflammation in eyes with active ocular toxoplasmosis and to identify relationships between signs of inflammation, complications (including elevated intraocular pressure [IOP]), other disease features, and host characteristics.

DESIGN

Multicenter, retrospective, cross-sectional study.

METHODS

We reviewed the medical records of 210 patients with toxoplasmic retinochoroiditis at seven international sites (North America, South America, and Europe) for information from the first examination at each site during which patients had active retinal lesions. Signs of inflammation included anterior chamber (AC) cells and flare and vitreous humor cells and haze. Retinal lesion characteristics included size (< or =1 disc area [DA] or >1 DA) and presence or absence of macular involvement.

RESULTS

AC cells and flare were related to vitreous inflammatory reactions (P < or = .041). One or more signs of increased inflammation were related to the following factors: older patient age, larger retinal lesions, and extramacular location. In 30% of involved eyes, there was evidence of elevated IOP (despite use of glaucoma medications by some patients); other complications were uncommon. IOP of more than 21 mm Hg was associated with both increased AC cells and elevated flare (both P < or = .001) and with macular involvement (P = .009). Inflammation seemed to be more severe among patients in Brazil than among those at other sites.

CONCLUSIONS

There is substantial variation between patients in the severity of intraocular inflammation associated with ocular toxoplasmosis, attributable to multiple host- and disease-related factors. Results suggest that disease characteristics also vary in different areas of the world. Elevated IOP at initial examination reflects the severity of inflammation.

Use of laser flare-cell photometry to quantify intraocular inflammation in patients with Behçet uveitis

PURPOSE

To assess the usefulness of laser flare-cell photometry to quantify intraocular inflammation in patients with Behçet disease.

METHODS

The study comprised 47 healthy individuals, 78 Behçet patients without ocular involvement, 54 Behçet patients with a uveitis attack and 53 Behçet patients with uveitis in clinical remission. A single observer assigned clinical scores to anterior chamber cells, vitreous haze, and fundus lesions in the attack group. Laser flare-cell photometry measurements were performed by another observer who was masked to the clinical findings. Fundus fluorescein angiography was performed only in the remission group, and fluorescein leakage was scored by a masked retina specialist. The risk of recurrent uveitis attack was analyzed in eyes with high versus low flare values in the remission group. Main outcome measures were anterior chamber flare in Behçet patients compared to the control group, and correlations of flare with clinical scores of intraocular inflammation and with fluorescein leakage. Mann-Whitney U-test, Spearman's bivariate correlation test, linear regression method, and Kaplan-Meier method were used for statistical analyses.

RESULTS

Mean flare was not increased in Behçet patients without ocular involvement. It was significantly higher in patients with Behçet uveitis both during attacks and in remission (P < 0.001 for each). A significant correlation was found between anterior chamber flare and anterior chamber cell score (rho = 0.705), vitreous haze score (rho = 0.588), and fundus score (rho = 0.464) in the attack group. In the remission group, there was a significant correlation between flare and fluorescein angiography leakage score, and the risk of recurrent uveitis attack was significantly higher in eyes with flare values >6 photons/msec than in eyes with flare values < or =6 photons/msec (right eyes, P < 0.001; left eyes, P = 0.0184).

CONCLUSIONS

Laser flare-cell photometry is a useful objective method in the quantitative assessment of intraocular inflammation in patients with Behçet uveitis. The use of this quantitative technique in clinical trials of Behçet uveitis may provide comparable data, as it gives an objective measure of intraocular inflammation. In clinical practice, it may reduce the need for fluorescein angiography because it seems to be especially useful in monitoring persistent retinal vascular leakage in patients who are clinically in remission.

Ocular association of HIV infection in the era of highly active antiretroviral therapy and the global perspective

Ocular involvement is a common complication of HIV infection. Since the late 1990s, widespread use of highly active antiretroviral therapy (HAART) has altered the spectrum, and reduced the incidence of ocular involvement in developed countries. The incidence of the most common ocular opportunistic infection, cytomegalovirus retinitis, has decreased tremendously. However, immune recovery uveitis secondary to HAART has emerged as a frequent visually threatening condition. Early diagnosis and treatment with periocular steroids is helpful in minimizing visual loss. Clinicians should also be aware that certain antimicrobial agents used to treat opportunistic infections in HIV-positive patients are associated with potentially serious ocular side effects. In developing countries, where most of the world's 40 million HIV-positive patients live, the spectrum and incidence of ocular involvement differ from those in developed countries. The lack of HAART availability is among the many causes of these differences, which may include nutritional factors, basic medical care availability and the levels of exposure to different infectious agents. These factors add to the already challenging task of treating ocular complications and preventing blindness in HIV-positive patients in developing countries.

Laser flare-cell photometry: methodology and clinical applications

Diagnosis and management of intraocular inflammation involves the assessment of cells and protein levels ("flare") in the aqueous humor. These factors are difficult to quantify precisely on clinical examination alone. Laser flare-cell photometry provides an automated technique to quantify these factors objectively, and it has been used in a variety of research and clinical situations to assess anterior segment inflammation. Any new technique requires evaluation to determine accuracy and reproducibility of measured values, and initial applications require critical appraisal to assess the value of the technique. Both in vitro and in vivo studies of laser flare-cell photometry have been performed to determine its validity and utility as a research and clinical tool. This article reviews published studies that describe the technique of laser flare-cell photometry; it provides new in vitro data that supplements information on the capabilities of this technique and factors that influence photometry results, and it reviews representative publications that have used laser flare-cell photometry for study of specific disease entities. This information can help clinicians and researchers to become familiar with the strengths and limitations of laser flare-cell photometry, to identify appropriate future uses for this technique, and to use it and interpret its results appropriately. Laser flare-cell photometry offers an opportunity to improve upon current techniques of inflammation assessment and should not be considered simply an objective surrogate for clinical grading of cells and flare at the slit-lamp biomicroscope. Its research applications and utility for monitoring patients with uveitis have not yet been fully explored.

Immune-recovery uveitis in patients with cytomegalovirus retinitis taking highly active antiretroviral therapy

PURPOSE

To investigate the clinical features associated with immune recovery in human immunodeficiency virus (HIV)-infected patients with cytomegalovirus retinitis who are taking highly active antiretroviral therapy.

METHODS

Sixteen patients were evaluated prospectively at the National Eye Institute, Bethesda, Maryland. Evaluation included a medical history and a complete ophthalmologic examination. The examination included best-corrected visual acuity score measured by means of logarithmic charts, slit-lamp biomicroscopy, dilated retinal examination, retinal photography, and fluorescein angiography. Immune-recovery uveitis was defined as the ocular inflammation associated with clinical immune recovery in patients taking potent antiretroviral regimens. The ophthalmic characteristics of immune-recovery uveitis were identified, and their effect on visual acuity was statistically analyzed.

RESULTS

The mean CD4+ T-lymphocyte count for the 16 patients taking highly active antiretroviral therapy at the time of evaluation was 393 cells/microl (range, 97-1,338 cells/microl). Immune-recovery uveitis was characterized by vitreitis and optic disk and macular edema. Clinically important complications of immune-recovery uveitis included cataract and epiretinal membrane formation. The visual acuity scores were significantly worse in the 23 eyes with cytomegalovirus retinitis (mean, 67.2 letters, 20/50) than in the nine eyes without cytomegalovirus retinitis (mean, 89.8 letters, 20/16) (P <.001). Regression analysis showed that a lower visual acuity score was associated with the presence of moderate to severe macular edema on fluorescein angiography and vitreous haze (P < or =. 001).

CONCLUSIONS

Immune-recovery uveitis is an important cause of visual morbidity in HIV-infected patients with cytomegalovirus retinitis in the era of highly active antiretroviral therapy. Although immune recovery associated with highly active antiretroviral therapy has allowed some patients to discontinue specific anticytomegalovirus therapy, the rejuvenated immune response can be associated with sight-threatening inflammation.

Decreased visual acuity in patients with cytomegalovirus retinitis and AIDS

PURPOSE

To investigate the causes of decreased visual acuity in patients with cytomegalovirus (CMV) retinitis in the acquired immunodeficiency syndrome (AIDS).

METHODS

All human immunodeficiency virus (HIV)-positive patients seen in two ophthalmology units over a 15 month period from September 1996 were included in this retrospective study. A detailed ophthalmic examination was performed on all patients and in addition those with CMV retinitis underwent serial fundus photography. Decreased visual acuity was defined as a best corrected visual acuity < or = 6/12. CMV and retroviral treatment, CD4+ count and HIV viral load were also documented for each patient.

RESULTS

Of 110 patients seen over the 15 month period, 26 (41 eyes) had a diagnosis of CMV retinitis. Twelve patients (16 eyes) with CMV retinitis had decreased visual acuity. The decreased visual acuity in 7 eyes was initially due to the CMV retinitis involving the macula and the optic nerve. Retinal detachment was responsible in 2 eyes and optic nerve atrophy in 1 eye. In 6 eyes (4 patients) the decreased visual acuity was due to a maculopathy--cystoid macular oedema and/or an epiretinal membrane in the presence of an inactive zone 2 or 3 CMV retinitis--with all these patients exhibiting a vitritis of varying grade. The decreased visual acuity in the maculopathy subgroup was irreversible in all except 1 eye, and 2 eyes in this category later developed a cataract.

CONCLUSION

In this series, CMV-retinitis-'related' maculopathy was a major (38%) cause of decreased visual acuity, occurring in the absence of zone 1 retinitis and despite inactive peripheral CMV retinitis. A varying degree of vitritis was an associated feature in all these patients. This study therefore highlights maculopathy as an important and previously unrecognised significant cause of visual morbidity in CMV retinitis.

Anterior uveitis associated with intravenous cidofovir use in patients with cytomegalovirus retinitis

AIM

Intravenous cidofovir is used to treat cytomegalovirus (CMV) retinitis, and has been reported to cause anterior uveitis. Relations were sought between this complication and patient characteristics that might help predict its occurrence.

METHODS

17 patients with AIDS and CMV retinitis who were treated with intravenous cidofovir were identified, and the following data collected in a retrospective chart review: demographic characteristics, duration of CMV retinitis, retinal lesion characteristics, dose and duration of cidofovir therapy, tests of renal function, CD4+ T lymphocyte counts, visual acuity, intraocular pressure, iris colour, history of diabetes mellitus, and use of concomitant medications. Case-control analyses were performed to determine risk factors for developing cidofovir associated uveitis.

RESULTS

Anterior uveitis characterised by pain, ciliary injection, and decreased visual acuity occurred in 10 patients (59%). Median interval to development of uveitis was 11 doses of cidofovir. Symptoms developed 4.4 (SD 2.5) days (median 3.5) after an infusion of cidofovir. Patients who developed uveitis had a significantly greater rise in CD4+ T lymphocyte count while receiving cidofovir (68.4 (75.7) x10(6)/l versus 5.0 (0.6) x10(6)/l, (p = 0.04)). By stepwise linear regression, this factor accounted for 33% (p = 0.03) of the effect of developing uveitis. Mean follow up time, intraocular pressure decline during cidofovir therapy, serum creatinine and urine protein concentrations, and rates of protease inhibitor use were not significantly different between patients who developed uveitis and those who did not. Uveitis responded to topical corticosteroids and cycloplegia.

CONCLUSION

Anterior uveitis in patients receiving intravenous cidofovir therapy may be related to improving immune function. The uveitis responds to treatment and may not preclude continuation of cidofovir.

Changing trends in cytomegalovirus retinitis with triple therapy

PURPOSE

Cytomegalovirus retinitis (CMVR) has been the most common cause of visual loss in AIDS patients. We investigate whether the pattern of disease has changed since the introduction of triple therapy.

METHODS

We reviewed the records of all patients with CMVR in one teaching hospital HIV unit over a 2 year period (n = 24). This included the opthalmic and systemic findings, HIV and CMV treatment, survival after diagnosis and CD4 results.

RESULTS

There has been a marked decrease in the number of patients developing new CMVR: from 21 eyes (15 patients) to 4 eyes (4 patients) in two consecutive 12 month periods between January 1996 and December 1997, coinciding with the introduction of triple therapy in October 1996. Median survival has increased from 376 days in the deceased patients to 598 days in the survivors on triple therapy. Median time to CMVR relapse has lengthened from 79 to 179 days in the triple therapy cohort. The pattern of ocular morbidity in the 11 eyes of the 7 surviving patients is also changing, with no new zone 1 disease, and a marked rise in the incidence of uveitis, maculopathy and cataracts.

CONCLUSION

Results suggest that triple therapy is associated with an increase in survival, a decrease in CMVR relapse and changes in ocular features. This transition has implications for current screening and treatment protocols.