THE THICKNESSES OF CHOROID, MACULAR SEGMENTS, PERIPAPILLARY RETINAL NERVE FIBER LAYER, AND RETINAL VASCULAR CALIBER IN HIV-1-INFECTED PATIENTS WITHOUT INFECTIOUS RETINITIS

Microvascular Changes during Viral Infections: A Systematic Review of Studies Using Retinal Vessel Diameter Assessments

Viral infection frequently affects the cardiovascular system, and vascular disturbances in patients can lead to health complications. One essential component of the cardiovascular system that is vulnerable to the inflammatory effects of viral infections is the microcirculatory system. As a suitable and practical non-invasive method to assess the structure and function of the retinal microcirculation, a proxy for the microcirculatory system, retinal fundus imaging can be used. We examined the impact of viral infections on retinal vessel diameters and performed a systematic analysis of the literature. Our search was carried out on PubMed using predefined search queries. After a methodological filtering process, we were able to reduce the corpus of 363 publications to 16 studies that met the search parameters. We used a narrative review style to summarise the observations. Six studies covered COVID-19, seven described HIV, and three were included in the subgroup called others, covering viruses, such as Dengue Fever and Crimean-Congo Haemorrhagic Fever. Analysis of the literature showed that viral infections are associated with alterations in the retinal vessels' vasoactivity. COVID-19 and other infections cause inflammation-associated the vasodilatation of microvasculature as a short-term effect of the infection. Long COVID-19 as well as HIV are the cause of chronic inflammation impacting microvascular morphology via retinal vessel diameter narrowing. The review emphasises the importance of the understudied area of viral infections' effects on retinal microcirculation. Continuous research in this area is needed to further verify retinal fundus imaging as an innovative tool for the optimal diagnosis of microvascular changes. As changes in the microvasculature precede changes in bigger arteries, the early detection of microvascular changes can go a long way in reducing the morbidity and mortality associated with cardiovascular diseases.

Comparison of Retinal Structure Using Optical Coherence Tomography Angiography between Persons with and without HIV Infection

HIV retinal microangiopathy is an important predictor for increased risk of mortality. Optical coherence tomography angiography (OCTA) can investigate microvascular changes resulting from retinal diseases. Study included 25 persons with HIV and 25 healthy persons. OCTA evaluated the vascularization of retinal layers, choriocapillary, and optic disk. HIV group had lower vessel flow density (VFD) in superficial plexus. No difference was observed in the deep plexus. VFD of the optic disk and peripapillary region showed no difference between the groups. HIV group showed a thinner retinal nerve fiber layer and smaller area of the optic disk rim. HIV infection is associated with VFD reduction in superficial retinal plexus, neural rim area reduction, and retinal nerve fiber layer thinning in individuals without microangiopathic alterations on fundus examination. Therefore, OCTA can find retinal changes before clinical evidence of retinopathy.

Comparison of retinochoroidal and optic nerve head microvascular circulation between HIV-positive patients and healthy subjects using optical coherence tomography angiography

PURPOSE

To evaluate the retinal, choroidal, and optic disc head microvascular circulation in human immunodeficiency virus (HIV)-infected individuals without retinopathy receiving highly active antiretroviral therapy (HAART) using swept-source optical coherence tomography angiography (SS-OCTA).

METHODS

This cross-sectional study included 100 eyes of 100 patients with HIV infection but no HIV-related ocular disease and 108 eyes of 108 age- and sex-matched healthy subjects as the control group. SS-OCTA was used to assess foveal avascular zone (FAZ) area, retinal nerve fiber layer thickness (RNFL), choriocapillaris (CC) flow area, outer retinal (OR) thickness, radial peripapillary capillary (RPC) vessel density (VD), ONH VD, and choroidal thickness.

RESULTS

No statistically significant difference was found between the two groups except in the foveal VD of the deep capillary plexus (DCP). The foveal VD of the DCP was lower in the HIV-positive group (P=0.011). The mean FAZ area (mm2), perimeter (mm), and CC flow area (mm) values were higher in the HIV-positive group at statistically significant levels (P=0.021, P=0.02, and P=0.039, respectively). However, no statistically significant differences were found between the two groups concerning the OR flow area, subfoveal choroidal thickness, or the VDs of the RPC or ONH.

CONCLUSIONS

This is the first study in the literature to evaluate the microvascular circulation of the ONH in HIV-positive patients. Although retinal and choroidal microvascular circulation decreased in HIV-positive patients receiving HAART treatment, we found no effect on the microvascular circulation of the ONH or RPC microvascular circulation. Our findings suggest that retinochoroidal microvascular circulation is affected in HIV-positive patients over time.

Macular Changes Observed on Optical Coherence Tomography Angiography in Patients Infected With Human Immunodeficiency Virus Without Infectious Retinopathy

Purpose

As the human immunodeficiency virus (HIV) pandemic is far from over, whether there are subclinical macular changes in HIV-positive patients is something that should not be overlooked. We aimed to apply optical coherence tomography angiography (OCTA) to assess the macular structure and microvasculature changes in patients with HIV without infectious retinopathy.

Methods

HIV-positive and -negative participants were included and classified into three groups: HIV-negative, HIV-positive, and HIV-positive with microvasculopathy. OCTA parameters regarding macular structure and microvasculature were analyzed.

Results

Compared with the HIV-negative group, the superficial retinal vessel density (VD) in the parafovea sectors and the whole Early Treatment of Diabetic Retinopathy Study (ETDRS) grid and the choroidal vascularity index (CVI) in the whole ETDRS grid were significantly decreased in the HIV-positive and HIV-positive with microvasculopathy groups (p < 0.05). No differences were found in OCTA parameters between the HIV-positive and HIV-positive with microvasculopathy groups. Retinal, retinal nerve fiber layer-ganglion cell layer-inner plexiform layer (RNFL-GCL-IPL), RNFL, GCL-IPL, and INL thickness showed a negative association with the duration of HIV diagnosis or antiretroviral therapy (ART) (all p < 0.05). All OCTA microvasculature parameters showed no association with HIV-related clinical variables (all p > 0.05).

Conclusions

Subclinical macular changes existed in HIV-infected patients without clinical infectious retinopathy. Substructures from inner retinal layers might be associated with HIV infection or ART duration.

Analysis of Macular Microvasculature in Human Immunodeficiency Virus Infection

PURPOSE

To evaluate the retinal and choroidal microvascular blood flow in patients with human immunodeficiency virus (HIV) infection using optical coherence tomography angiography (OCTA).

METHODS

Macular OCTA parameters including vessel density (VD) of parafoveal superficial capillary plexus (SCP-VD) and deep capillary plexus (DCP-VD), foveal vessel density (FD), foveal avascular zone area, and flow area of choriocapillaris were analyzed in 42 HIV-positive patients, and compared with 42 healthy controls.

RESULTS

The mean SCP-VD, DCP-VD and FD were significantly lower in HIV-positive group compared with controls (p < .001, p = .014, p = .026; respectively). Reduced SCP-VD was associated with higher HIV RNA plasma level (r = -0.400, p = .021) and lower CD4 + T cell count (r = 0.314, p = .046) in HIV-positive patients.

CONCLUSIONS

Macular microvascular blood flow is affected by HIV infection. OCTA can detect microvascular flow abnormalities in retinal capillary plexus in HIV-positive patients.

The long-term effect of human immunodeficiency virus infection on retinal microvasculature and the ganglion cell-inner plexiform layer: an OCT angiography study

PURPOSE

To investigate the long-term effect of HIV infection on the ganglion cell-inner plexiform layer and retinal capillary network.

METHODS

This prospective, cross-sectional case-control study included 45 HIV-infected patients and 45 healthy individuals. Optical coherence tomography angiography (OCTA) was used for the assessment of macular, peripapillary retinal nerve fiber layer (RNFL) thicknesses, ganglion cell-inner plexiform layer, vessel density, perfusion density, and foveal avascular zone.

RESULTS

The mean disease duration was 7.3 ± 1.9 years (range, 5-12 years) in the HIV group. The mean CD4 count (nadir) for all the patients was 147.09 ± 122 cells/mm³ and the mean RNA was 173.6 ± 913.8 copies/ml. No statistically significant difference was determined between the groups in respect of the average and foveal MT (p = 0.05). A significant difference was found between the two groups in respect of the mean VD and PD parameters (p < 0.05). Peripapillary PD was significantly decreased in the HIV group. There was a significant difference between the average and superior and inferior half-region of GC-IPL values. Using Pearson's correlation analysis, no significant correlation was determined between the duration of HIV infection and mean GC-IPL, MT and VD, and PD values (r - 0.223, p 0.141; r - 0.223, p 0.141; r - 0.169, p 0.268; r - 0.105, p 0.491; r - 0.095, p 0.535 respectively).

CONCLUSIONS

The results of this study provide evidence of microvascular and neuroretinal loss in individuals with well-suppressed HIV infection, compared with healthy control subjects. OCTA is an important test for the screening of retinal microvascular changes over time in HIV-infected cases.

Absence of peripapillary retinal nerve-fiber-layer thinning in combined antiretroviral therapy-treated, well-sustained aviremic persons living with HIV

Purpose

To compare peripapillary retinal nerve-fiber–layer (pRNFL) thickness, total retina macular volume, and ganglion-cell-layer (GCL) macular volume and thickness between persons living with HIV (PLHIVs) with well-controlled infections and good immune recovery, and sex- and age-matched HIV-uninfected controls (HUCs).

Methods

This prospective cross-sectional study (www.clinicaltrials.gov identifier: NCT02003989) included 56 PLHIVs, infected for ≥10 [median 20.2] years and with sustained plasma HIV-load suppression on combined antiretroviral therapy (cART) for ≥5 years, and 56 matched HUCs. Participants underwent spectral-domain optical coherence tomography (SD-OCT) with thorough ophthalmological examinations and brain magnetic resonance imaging (MRI). Their overall and quadrant pRNFL thicknesses, total macular volumes, and GCL macular volumes and thicknesses were compared. Cerebral small-vessel diseases (CSVD) complied with STRIVE criteria.

Results

Median [interquartile range, IQR] ages of PLHIVs and HUCs, respectively, were 52 [46–60] and 52 [44–60] years. Median [IQR] PLHIVs’ nadir CD4+ T-cell count and current CD4/CD8 T-cell ratio were 249/μL [158–350] and 0.95 [0.67–1.10], respectively; HIV-seropositivity duration was 20.2 [15.9–24.5] years; cART duration was 16.8 [12.6–18.6] years; and aviremia duration was 11.4 [7.8–13.6] years. No significant between-group pRNFL thickness, total macular volume, macular GCL-volume and -thickness differences were found. MRI-detected CSVD in 21 (38%) PLHIVs and 14 (25%) HUCs was associated with overall thinner pRNFLs, and smaller total retina and GCL macular volumes, independently of HIV status.

Conclusions

SD-OCT could not detect pRNFL thinning or macular GCL-volume reduction in well-sustained, aviremic, cART-treated PLHIVs who achieved good immune recovery. However, CSVD was associated with thinner pRNFLs and GCLs, independently of HIV status.

Retinal nerve fiber layer changes based on historic CD4 nadir among HIV positive patients undergoing glaucoma evaluation

AIM

To determine relationships between retinal nerve fiber layer (RNFL) thickness and nadir CD4 cell count in human immunodeficiency virus (HIV) positive patients evaluated for glaucoma suspicion.

METHODS

Data were reviewed for 329 HIV positive patients evaluated for glaucoma suspicion. High-definition optical coherence tomography (OCT) RNFL measurements were obtained at least 6mo apart. Analyses were performed to identify relationships between nadir CD4 count and RNFL thickness.

RESULTS

Totally 110 eyes of 55 patients met inclusion criteria, of which 46 eyes were from subjects with nadir CD4<200 cells/mm³ and 64 had nadir CD4≥200 cells/mm³. Patients with nadir CD4<200 cells/mm³ had significantly thicker superior (119.7±18.6 µm) and temporal (63.8±11.7 µm) quadrants at time of initial OCT compared to the superior (112.8±16.8 µm, P=0.048) and temporal (57.1±11.9 µm, P=0.004) quadrants of patients with higher nadir CD4. This trend toward thicker RNFL among subjects with lower nadir CD4 cell counts persisted at the time of follow up OCT where participants with nadir CD4<200 cells/mm³ showed average RNFL thickness in the superior and temporal quadrants of 117.9±18.3 µm and 63.8±12.8 µm, respectively, compared to a superior thickness of 110.5±16.9 µm (P=0.034) and temporal thickness of 57.3±11.6 µm (P=0.007) among those with higher nadir CD4.

CONCLUSION

Patients with lower nadir CD4 cell counts have thicker RNFL in the superior and temporal quadrants compared to those with higher nadir CD4 counts. RNFL thickness in HIV positive patients may be affected by historic HIV disease control and should be considered when evaluating HIV positive patients for glaucoma.