Retinal nerve fibre layer thickness and contrast sensitivity in HIV-infected individuals in South Africa: a case-control study

Functional and structural neuroretinal disorders in HIV Controllers. Prospective cohort study

OBJECTIVE

To estimate the prevalence and cumulative incidence of neuro-retinal-disorders (NRD) in HIV-controllers.

DESIGN

Prospective, single-centre, cohort study of people living with HIV (PLWH): elite-controllers, long-term-non-progressors and early diagnosed.

METHODS

The study compared "HIV-controllers" (including elite-controllers and long-term-non-progressors), who were not on antiretroviral therapy (ART), and "HIV-treatment" (HIV-infected subjects with a recent diagnosis and on ART). A matched cohort of "non-HIV subjects" was created. NRD was defined as at least one altered (not normal) ophthalmological parameter (functional or structural). Functional (visual acuity, contrast sensitivity, chromatic vision, visual field) and structural parameters (ganglion cells, macular nerve fibre layer, peripapillary nerve fibre layers, vascular calibre) as well as quality of life (Medical Outcomes Study-HIV Short Form-30) were assessed.

RESULTS

Between March 2012 and November 2015, the study included all HIV-controllers (16 elite-controllers, 1 long-term-non-progressor), 11 HIV-treatment and 16 non-HIV. Prevalence of NRD at baseline was 88.2% (15/17, 95% CI: 65.7%-96.7%), 90.9% (10/11, 95% CI: 62.3%-98.4%) and 56.3% (9/16, 95% CI: 33.2%-76.9%), respectively. Cumulative incidence at 3 years was 50% (1/2), 100% (1/1) and 33.3% (2/6), respectively. None of the participants manifested ocular clinical symptoms. Three years later, prevalence of NRD was 92.3% (12/13, 95% CI: 66.7%-98.6%), 75% (6/8, 95% CI: 40.9%-92.9%) and 50.0% (7/14, 95% CI: 26.8%-73.2%), respectively. Contrast sensitivity and structural parameters were globally the most affected among PLWH. Quality of life (total score) [median (interquartile range)] at baseline and 3 years was 82 (71-89) and 74 (63.5-79.25) in HIV-controllers and 80 (73-88) and 88 (83-92) in HIV-treatment.

CONCLUSIONS

HIV-controllers and those individuals on ART presented a higher percentage of NRD than non-HIV. Our results suggest that NRD could be a biomarker of ocular aging among PLWH.

Inflammatory mechanisms contributing to retinal alterations in HIV infection and long-term ART

People living with HIV (PLWH) may face an increased risk of eye complications associated with ageing, chronic inflammation, and the toxicity arising from long-term antiretroviral therapy (ART). This review aims to understand how inflammatory pathways contribute to retinal alterations observed in PLWH on long-term ART. This review was conducted using four electronic database searches, namely Scopus, Hinari, Google Scholar, and PubMed; from 1996 (when ART became available) until January 2022, without language restriction. Sources from clinical trials, meta-analyses, randomised controlled trials, and systematic reviews were used. Dysregulated para-inflammation (chronic inflammation) damages the blood-retina barrier, resulting in the altered retinal immune privilege and leading to the development of retinal and blood vessel changes. There is an interplay between the effects of the disease versus ART. ART causes mitochondrial toxicity, which affects the retinal ganglion cells and retinal pigment epithelium (RPE) due to oxidative stress. Infection by HIV also affects retinal microglia, which contributes to RPE damage. Both of these mechanisms affect the blood vessels. Assessing the integrity of the inner and outer blood-retina barrier is a pivotal point in pinpointing the pathogenesis of inner retinal alterations. Optical coherence tomography is a valuable tool to assess these changes. There is a paucity of research to understand how these structural changes may affect visual function, such as contrast sensitivity and colour vision.

Significant loss of retinal nerve fibre layer and contrast sensitivity in people with well controlled HIV disease: implications for aging with HIV

Objective

Antiretroviral therapy has decreased the prevalence of retinal opportunistic infections in people living with HIV (PLWH). However, abnormalities in visual function are evident and may be associated with an early onset of aging in PLWH. In this study, we examined the Retinal Nerve Fibre Layer (RNFL) thickness and visual function in PLWH and HIV non-infected controls in Malaysia.

Design

Cross-sectional study.

Methods

Two hundred and two (202) PLWH without retinal opportunistic infection and 182 age-matched, HIV seronegative individuals were enrolled. PLWH were recruited from the Infectious Disease clinic at the University Malaya Medical Centre. Controls were recruited among the hospital staff and community volunteers. RNFL thickness was measured with spectral domain optical coherence tomography (SDOCT). Visual functions include visual acuity using LogMAR chart and contrast sensitivity using Pelli- Robson Chart.

Results

All PLWH (mean age 46.1 years ± 9.9 years) in the study were on ART and 61.2% had a CD4+ T-cell count more than 500 cell/μl. The mean visual acuity was similar between the two groups (LogMAR 0.05 vs. 0.07, p = 0.115). Contrast sensitivity was lower in PLWH compared to HIV seronegative individuals (1.90 vs 1.93, p = 0.032). RNFL thickness was significantly thinner in the temporal quadrant for PLWH compared to controls (68.89 μm vs 74.08 μm, p = 0.001).

Conclusion

Changes in RNFL thickness and contrast sensitivity were seen in PLWH despite their relatively young age and well controlled HIV disease. The changes reflect structural and functional deficits, and could have long-term implications on their health trajectory.

Development of retinal structure in perinatally HIV-infected children and adolescents: A longitudinal and cross-sectional assessment

In perinatally HIV-infected (PHIV) children, cross-sectional studies reported on subtle structural retinal differences and found associations between the retina and structural brain changes. Our objective is to investigate whether neuroretinal development in PHIV children is similar to the development in healthy matched controls and to explore associations with the brain structure. We measured RT using optical coherence tomography (OCT) on two occasions in 21 PHIV children or adolescents and 23 matched controls-all with good visual acuity-with a mean interval of 4.6 years (SD 0.3). We also included 22 participants (11 PHIV children and 11 controls) together with the follow-up group for a cross-sectional assessment using a different OCT device. Magnetic resonance imaging (MRI) was used to assess the white matter microstructure. We used linear (mixed) models to assess changes in RT and its determinants (over time), adjusting for age and sex. The development of the retina was similar between the PHIV adolescents and controls. In our cohort, we found that changes in the peripapillary RNFL was significantly associated with changes in WM microstructural makers: fractional anisotropy (coefficient = 0.030, p = 0.022) and radial diffusivity (coefficient = -0.568, p = 0.025). We found comparable RT between groups. A thinner pRNFL was associated with lower WM volume (coefficient = 0.117, p = 0.030). PHIV children or adolescents appear to have a similar development of the retinal structure. In our cohort, the associations between RT and MRI biomarkers underscore the relation between retina and brain.

Functioning Problems Associated with Health Conditions with Greatest Disease Burden in South Africa: A Scoping Review

A notable rise in health-related disability for which evidence-based rehabilitation is beneficial is evident in low-to-middle income countries. This scoping review aimed to systematically identify and map the most common functioning problems associated with health conditions that contribute most to disability in South Africa using the International Classification of Functioning, Disability and Health (ICF) framework. Peer-reviewed evidence published from January 2006 to December 2021 was systematically searched from five databases. Some 268 studies reporting on functioning problems (impairments, activity limitations, and participation restrictions) in South African adults (>18 years) related to 10 health conditions were included. A total of 130 different functioning problems were mapped to the ICF. The most prevalent problems (top 20) were related to mobility, pain, and mental health but spanned across several ICF domains and were mostly in patients at primary care. The high prevalence and wide range of functioning problems may be particularly burdensome on an already strained primary health care (PHC) system. This points towards targeted planning of innovative strategies towards strengthening rehabilitation service delivery at primary care to address these complexities where there is an inadequate rehabilitation workforce.

The relationship between retinal structure and visual function in non-immuno-compromised people living with HIV without retinitis on antiretroviral therapy

BACKGROUND

This study sought to establish the association between retinal morphology, visual function and linear parameters of cerebral atrophy in non-immunocompromised people living with HIV (NIPLHIV).

METHODS

Sixty participants (30 NIPLHIV, 30 controls), aged 18-45 years, were sourced from an outpatient clinic in South Africa. NIPLHIV on antiretroviral therapy (ART) had elevated CD4 counts and low viral loads. Macula thickness and volume measurements were obtained using the Spectralis optical coherence tomographer. Contrast sensitivity (CS), colour vision and visual-evoked potentials (VEP) were also obtained. Linear parameters of cerebral atrophy (Sylvian fissure ratio, SFR) and bicaudate nucleus ratio (BCR) were all acquired from computed tomography (CT) scans. Associations between retinal thickness and volume and visual function were established by principal component factor analysis.

RESULTS

CS scores were indirectly associated with the Inner Nuclear Layer (INL)-ETDRS thickness and volume subfields (co-efficient = -0.07; p = 0.02 and -0.11; p = 0.001), respectively. F100 total error scores (TES) were directly associated with the thicknesses of Ganglion Cell Layer-ETDRS subfields (co-efficient = 6.06; p = 0.04) but indirectly associated with INL-ETDRS subfields (co-efficient = -5.49; p = 0.04). F100-TES were indirectly associated with volumes of RNFL (Retinal Nerve Fibre Layer)-ETDRS subfields (co-efficient = -5.54; p = 0.02) and inner retina -ETDRS subfields (co-efficient = -6.70; p = 0.02). P100 latency was directly associated with RNFL-ETDRS subfield thickness (co-efficient = 2.90; p = 0.02) and volumes of outer retina subfields (co-efficient = 2.72; p = 0.04). CS scores were directly associated with SFR (co-efficient = -0.04; p = 0.01). F100-TES were directly associated with BCR (co-efficient = 0.003; p = 0.004) and SFR (co-efficient = 0.002; p = 0.02). P100 latency was indirectly associated with BCR (co-efficient = -0.001; p = 0.03).

CONCLUSION

The recognition of associations may be the first step in the proposal to develop a framework for the surveillance of vision in patients with NIPLHIV. We recommend a study of the sample population to track the stability of these observations before general recommendations for clinical care.

The Integrity of Retinal Morphology in Non-immunocompromised People Living with HIV on Antiretroviral Therapy

SIGNIFICANCE

Non-immunocompromised people living with HIV (NIPLHIV) share a similar immunocompetence to non-HIV (HIV) people with an elevated cluster of differentiation 4 (CD4) count in the era of antiretroviral therapy (ART). This has reduced the incidence of HIV retinopathy, thus raising the question of the integrity of the retinal morphology in NIPLHIV with longer life expectancy.

PURPOSE

The study assessed the retinal thickness and volume of NIPLHIV without retinitis on ART and attempted to find associations with linear parameters of cerebral atrophy.

METHODS

The study was conducted at a public hospital in South Africa. All people living with HIV were on ART with CD4 counts above 350 cells/mm3 and viral loads less than 10,000 copies/mL. The Heidelberg Spectralis ocular coherence tomographer assessed the retinal thickness and volume for comparison between 30 NIPLHIV and 30 HIV-negative participants. A subset of the HIV group obtained a computed tomography scan to determine the bicaudate ratio and the sylvian fissure ratio to assess cerebral atrophy. Independent t tests were performed to identify differences in retinal thickness and volume. Multivariate linear regressions measured associations between retinal thickness and volume with cerebral atrophy.

RESULTS

The NIPLHIV group had a thicker mean global temporal subfields at Early Treatment Diabetic Retinopathy Study (ETDRS) 3 mm (P = .047) and ETDRS 6 mm (P = .03). The mean global temporal subfield volume at ETDRS 3 mm was also increased in the NIPLHIV group (P = .02). Nasal macula retinal nerve fiber layer thickness and the inferior inner nuclear layer macula volume were directly related to the bicaudate ratio, whereas the volumes at the outer retinal layer subfields of the macula were inversely related to sylvian fissure ratio in NIPLHIV.

CONCLUSIONS

Macula thickness and volumetric differences do exist in NIPLHIV. Practitioners should keep NIPLHIV under retinal morphometric surveillance because they live longer. Associations of cerebral atrophy with retinal morphology may be used to monitor cerebral atrophy in NIPLIV on ART.

Ocular manifestations and refractive errors among people living with HIV in Pune, India: a cross-sectional study

Objective

We aimed to determine the ocular manifestation and refractive error prevalences among people living with HIV (PLHIV) in Pune, India.

Methods

This cross-sectional study included HIV-infected adults attending a National AIDS Research Institute clinic. Ophthalmologic examination included visual acuity estimation, refraction, orthoptic evaluation, slit lamp and fundus examination, and photography.

Results

In total, 441 HIV-infected individuals were enrolled. The participants' median age was 44 (interquartile range 38–49) years and 227 (51.5%) were men. Refractive errors occurred in 132 (29.9%) individuals. Ocular manifestations were present in 93 (21.1%) participants and the most frequent was cataract in 59 (13.4%) participants. Multivariate logistic regression analysis showed that participants who were illiterate (adjusted odds ratio [AOR] 2.80, 95% confidence interval [CI] 1.47–5.33) and those aged greater than 40 years (AOR 5.59, 95% CI 2.69–11.61) were more likely to have ocular manifestations. The odds of having ocular manifestations were greater in participants with treatment substitution or changes (AOR 2.11, 95% CI 1.16–3.82).

Conclusions

Cataract and refractive errors were prevalent among PLHIV. PLHIV should be encouraged to have regular ophthalmic checkups. Individuals with lower education levels and older age should be counseled regarding eye care and timely reporting of ocular symptoms.

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

PURPOSE

To evaluate choroidal, macular, peripapillary retinal nerve fiber layer (RNFL) thicknesses and retinal vascular caliber alterations in HIV-1-infected patients without opportunistic infections.

METHODS

This cross-sectional study included 45 HIV-1-infected patients and 47 healthy subjects. Spectral domain optical coherence tomography was used for assessment of choroidal, macular, peripapillary RNFL thicknesses and retinal vascular caliber alterations.

RESULTS

The mean CD4 count was 426 ± 226 cells per milliliter and the mean HIV-1 RNA level was 1.8 × 10 ± 3.6 × 10 copies/mL in HIV-infected group. Central inner plexiform, superior photoreceptor, superior and nasal retinal pigment epithelium layers were thinner in HIV-infected patients compared with control subjects (P < 0.05). The differences in sectoral retinal thicknesses lost their significance after Bonferroni correction (P < 0.01). The average thickness of pericentral retina within 3 mm was thinner in the photoreceptor layer in HIV-infected patients compared with control subjects (P = 0.033). The differences in peripapillary RNFL thickness, choroidal thickness, and retinal vascular caliber were not significant between the groups. Choroidal thickness and pericentral outer plexiform were thinner, whereas peripapillary RNFL was thicker in newly diagnosed cases (16 patients) compared with patients having treatment for at least 4 months or longer (27 patients, P < 0.05, Mann-Whitney U test). HIV-1 RNA showed negative correlation with choroidal thickness (r = -0.435, P = 0.003) and positive correlation with peripapillary RNFL in central (r = 0.323, P = 0.032) and superonasal (r = 0.369, P = 0.014) sectors.

CONCLUSION

Choroidal thickness was thinner in newly diagnosed patients compared with patients on treatment. Viral load showed negative correlation with choroidal thickness. Retinal segmental alterations occurred in HIV-infected patients compared with control subjects.

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 fibre layer thickness in a normal black South African population

BACKGROUND

The measurement of retinal nerve fibre layer (RNFL) thickness on spectral domain OCT (SD-OCT) are compared with built-in age- and gender-matched European normative databases and this difference is used to assist with glaucoma diagnosis. However, there are differences in RNFL thickness between population groups. Therefore, using the built in European normative database as a comparison across all population groups could lead to erroneous results, due to the basic assumption that the normative values for non-European populations are the same as their European counterparts.

METHODS

Cross-sectional study of RNFL thickness in normal black South African patients.

RESULTS

One hundred and thirty-two eyes of 132 patients were enroled in this study. The mean (SD) age of patients in this study was 41.3 (12.5) years. Males comprised 40.9% (n = 54; p = 0.0367). All RNFL sectors except the temporal sector were significantly thicker than the reference database. The RNFL sectors measured as follows: global (108.7 µm, p < 0.001), superotemporal (152.4 µm, p < 0.001), superonasal (132.6 µm, p < 0.001), inferotemporal (150.1 µm, p < 0.001), inferonasal (129.2 µm, p < 0.001), nasal (77.7 µm, p < 0.001), temporal 74.8 µm, p = 0.9534).

CONCLUSION

The RNFL thickness of normal black South Africans is significantly thicker than that of the European database on the Spectralis SD-OCT. This needs to be taken into account when performing RNFL thickness measurements on black patients.

A comparative study on retinal thickness of the macular region among AIDS patients with normal ocular fundus, HIV-related microvascular retinopathy patients, and cytomegalovirus retinitis patients

The present study aims to measure the retinal thickness of the macular region of AIDS patients with normal ocular fundus, HIV-related microvascular retinopathy patients and cytomegalovirus retinitis (CMVR) patients by optical coherence tomography, and generalize the characteristics of retinal thickness of these 3 groups of patients.In this retrospective case series, the study object comprised of 111 AIDS patients who received diagnosis and treatment in the Ophthalmology Department of Beijing Youan Hospital. There are 33 patients in the AIDS normal ocular fundus group, 47 patients in the HIV-related microvascular retinopathy group, and 31 patients in the CMVR group. The retinal thickness of the macular region of these above patients was measured. The main indicators were retinal thickness of 9 macular partitions, best corrected visual acuity, CD4+ T lymphocyte count, and the start of highly active antiretroviral therapy.In the CMVR group, except for the nasal-outer and temporal-outer sectors, the thickness of the affected eye of the rest of the regions was greater than that of healthy eye (P < .05). Furthermore, there was a difference in thickness of the superior-outer and inferior-outer sectors between the AIDS normal ocular fundus group and HIV-related microvascular retinopathy group. The difference in thickness of the superior-inner sector between patients in the AIDS normal ocular fundus group and CMVR group was not statistically significant, while the difference in thickness of the rest of the regions was statistically significant. The difference in thickness of various regions between patients in the HIV-related microvascular retinopathy group and CMVR group was statistically significant.The retinal thickness of patients in the CMVR group generally increased, the retinal thickness of superior-outer and inferior-outer sections of patients in the HIV-related microvascular retinopathy group increased, when compared to the AIDS normal ocular fundus group. These optical coherence tomography (OCT) examination results present its own characteristics in different eye diseases in AIDS patients, and different stages of eye disease.

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.

The role of optical coherence tomography in therapeutics and conditions, which primarily have systemic manifestations: a narrative review

Optical coherence tomography is designed to evaluate in vivo qualitative and quantitative changes of the anterior segment, optic nerve and the retina. Initial applications of this technology were confined mainly to ophthalmic diseases. However recently, numerous studies have evaluated its use in systemic conditions and in therapeutics where, optic nerve and retinal architecture can be assessed to monitor progression of systemic conditions and its response to treatment. This is a narrative review aimed at evaluating the debate surrounding the role of spectral domain optical coherence tomography, in systemic conditions where optic nerve affection can be measured and be used in the diagnosis, monitoring and assessment of treatment effect as a non-invasive, quick, novel technique.

Correlation between inner retinal layer thickness and cognitive function in HIV: new insights from an exploratory study

OBJECTIVE

To compare retinal layer thickness in HIV-infected subjects with (CI-HIV) and without (NCI-HIV) cognitive impairment, with a control population and to correlate this with the cognitive status of the patient and other clinical parameters.

DESIGN

Single-center cross-sectional study.

METHODS

Participants with controlled HIV infection aged between 40 and 70 years and sex-matched and age-matched controls were enrolled. Retinal nerve fiber layer (RNFL), ganglion cell layer (GCL) and inner plexiform layer (IPL) thickness were assessed using optical coherence tomography. These measurements in HIV patients were compared with those in controls. Age-related and sex-related changes were compared in both groups. Other variables studied in HIV patients included: duration of HIV infection, CD4 cell count nadir, antiretroviral therapy regimen and cognitive status using the Montreal Cognitive Assessment (MoCA) test.

RESULTS

Sixty-nine individuals, 34 with and 35 without cognitive impairment, and 70 controls were enrolled. GCL was significantly thinner in CI-HIV patients compared with NCI-HIV patients and controls (P = 0.01 and P = 0.02, respectively). GCL and IPL thickness significantly decreased with age in patients with HIV (P = 0.0003, P = 0.02, respectively, for the entire cohort). This change was not seen in controls. MoCA test score significantly decreased with age in HIV patients and controls. GCL thickness positively correlated with cognitive function across the entire HIV cohort (P = 0.02).

CONCLUSION

GCL was thinner in HIV patients with cognitive impairment. GCL thickness correlated positively with cognitive function and negatively with age in HIV patients. GCL thickness may reflect accelerated cognitive aging in HIV.

Retinal Parameters as Compared with Head Circumference, Height, Weight, and Body Mass Index in Children in Kenya and Bhutan

The retina shares embryological derivation with the brain and may provide a new measurement of overall growth status, especially useful in resource-limited settings. Optical coherence tomography (OCT) provides detailed quantification of retinal structures. We enrolled community-dwelling children ages 3–11 years old in Siaya, Kenya and Thimphu, Bhutan in 2016. We measured head circumference (age < 5 years only), height, and weight, and standardized these by age and gender. Research staff performed OCT (iScan; Optovue, Inc., Fremont, CA), measuring the peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell complex (GCC) thicknesses. A neuro-ophthalmologist performed quality control for centration, motion artifact, and algorithm-derived quality scores. Generalized estimating equations were used to determine the relationship between anthropometric and retinal measurements. Two hundred and fifty-eight children (139 females, average age 6.4 years) successfully completed at least one retinal scan, totaling 1,048 scans. Nine hundred and twenty-two scans (88.0%) were deemed usable. Fifty-three of the 258 children (20.5%) were able to complete all six scans. Kenyan children had a thinner average GCC (P < 0.001) than Bhutanese children after adjustment for age and gender, but not RNFL (P = 0.70). In models adjusting for age, gender, and study location, none of standardized height, weight, and body mass index (BMI) were statistically significantly associated with RNFL or GCC. We determined that OCT is feasible in some children in resource-limited settings, particularly those > 4 years old, using the iScan device. We found no evidence for GCC or RNFL as a proxy for height-, weight-, or BMI-for-age. The variation in mean GCC thickness in Asian versus African children warrants further investigation.

Choroidal Thickness in Patients Diagnosed with Human Immunodeficiency Virus Infection: Results from Two Populations of Different Ethnicities

Purpose: To measure the choroidal thickness among subjects with human immunodeficiency virus (HIV) infection from two diverse ethnic populations and to compare it with healthy controls. Methods: Subjects with HIV infection and healthy controls were enrolled in two referring centers in Italy and India. Clinical data were collected. All subjects underwent enhanced-depth imaging optical coherence tomography and measurement of choroidal thickness. Results: A total of 68 eyes from 68 patients with HIV (44 Caucasian, 24 Indians) and 60 eyes from 60 healthy volunteers (36 Caucasian, 24 Indians) were included. Mean choroidal thickness was significantly higher in HIV patients compared to controls (312.91 ± 65 µm vs. 266.57 ± 47 µm; p < 0.001). Choroidal thickness was higher among subjects with HIV-related retinopathy compared to HIV without retinopathy (285 ± 30 µm vs. 352 ± 17 µm; p < 0.01). Conclusions: Patients with HIV infection, especially with HIV microangiopathy, have thicker choroid compared to age- and gender-matched healthy control subjects. These changes may be related to HIV-associated choroidal vascular dysfunction.

Study of Retinal Nerve Fibre Layer Thickness and Visual Contrast Sensitivity in HIV Positive Individuals

INTRODUCTION

Measurement of Retinal Nerve Fibre Layer Thickness (RNFLT) by Optical Coherence Tomography (OCT) is a sensitive, non invasive and cheap method of detecting early retinal changes in a variety of diseases. In HIV infection, RNFLT is altered and this may have effect on other visual functions like Contrast Sensitivity (CS) and visual acuity. Such ocular pathology can affect the daily life and profession (especially driving) of HIV infected individuals. However, studies on this topic in HIV infected population are rare from India.

AIM

To study RNFLT, CS and their correlation in a sample of HIV positive Indian population.

MATERIALS AND METHODS

The present cross-sectional study was done in a tertiary care medical college hospital of Eastern India between May 2016 and September 2016. We did this study on HIV positive subjects with no clinically apparent ocular infection or other pathology. In this study, we have measured the RNFLT using the HRA-OCT Spectralis machine. The CS was tested using a smartphone version of the Pellie-Robson chart. CD4 count, visual acuity and colour vision were also tested. The data was analysed using SPSS version 20.0 for any correlation between these parameters. Pearson coefficient was used for continuous data and Spearman rank correlation was used for categorical data. A p-value <0.05 was considered significant.

RESULTS

We had 17 patients, that is 34 eyes. RNFLT loss was found in 21% of the eyes and borderline thinning was found in a further 26%. Predominantly, the temporal quadrant was involved. The mean of log CS was 1.33±0.38. Taking 1.5 as the cut-off value for normalcy, 47% of the eyes tested showed decreased CS. Log CS showed significant correlation with RNFLT of the temporal quadrant only (r=0.37; 95% C.I. 0.041 to 0.631; p=0.02). Temporal RNFLT also showed statistical correlation with the CD4 count. The low CS was also significantly correlated with low visual acuity (r=0.5).

CONCLUSION

In HIV infected persons, subtle ocular changes may occur and this may affect visual functions quite early. Hence, a comprehensive eye check-up should include parameters like CS and OCT.

Neuroretinal Degeneration in HIV Patients Without Opportunistic Ocular Infections in the cART Era

Subtle structural and functional retinal abnormalities, termed 'HIV-associated Neuroretinal Disorder (HIV-NRD)', have been reported in HIV patients receiving combination antiretroviral therapy (cART), without infectious retinitis or any apparent fundus abnormalities otherwise. In this review, we provide an overview of studies investigating HIV-NRD in HIV patients without opportunistic ocular infections in the cART era, and try to elucidate underlying mechanisms and associated risk factors. Most studies focused on patients with severe immune-deficiency and demonstrated that patients with nadir CD4 counts<100 cells/μL are most at risk for neuroretinal damage, with a thinner retinal nerve fiber layer, subtle loss of color vision and/or contrast sensitivity, visual field deficits, and subnormal electrophysiological responses. In contrast, alterations in retinal vascular calibers and retinal blood flow were not associated with nadir CD4 counts, but instead with detectable viremia, suggesting a role for (chronic) inflammation in microvascular damage. Although the alterations in visual function are subtle, they can lead to difficulties in activities, such as reading or driving, thereby affecting quality of life. Since HIV has become a chronic disease, its long-term effects with respect to visual function loss become more important, as is recently emphasized by a longitudinal study, reporting that AIDS patients with HIV-NRD have higher risks of developing bilateral visual impairment and even blindness than patients without HIV-NRD. The question remains whether patients with high (>350 cells/μL) nadir CD4 counts and well-suppressed HIV infection on cART remain at risk for HIV-NRD, as this group constitutes a growing part of the aging HIV-infected population.

Retinal Thickening and Photoreceptor Loss in HIV Eyes without Retinitis

Purpose

To determine the presence of structural changes in HIV retinae (i.e., photoreceptor density and retinal thickness in the macula) compared with age-matched HIV-negative controls.

Methods

Cohort of patients with known HIV under CART (combination Antiretroviral Therapy) treatment were examined with a flood-illuminated retinal AO camera to assess the cone photoreceptor mosaic and spectral-domain optical coherence tomography (SD-OCT) to assess retinal layers and retinal thickness.

Results

Twenty-four eyes of 12 patients (n = 6 HIV-positive and 6 HIV-negative) were imaged with the adaptive optics camera. In each of the regions of interest studied (nasal, temporal, superior, inferior), the HIV group had significantly less mean cone photoreceptor density compared with age-matched controls (difference range, 4,308–6,872 cones/mm²). A different subset of forty eyes of 20 patients (n = 10 HIV-positive and 10 HIV-negative) was included in the retinal thickness measurements and retinal layer segmentation with the SD-OCT. We observed significant thickening in HIV positive eyes in the total retinal thickness at the foveal center, and in each of the three horizontal B-scans (through the macular center, superior, and inferior to the fovea). We also noted that the inner retina (combined thickness from ILM through RNFL to GCL layer) was also significantly thickened in all the different locations scanned compared with HIV-negative controls.

Conclusion

Our present study shows that the cone photoreceptor density is significantly reduced in HIV retinae compared with age-matched controls. HIV retinae also have increased macular retinal thickness that may be caused by inner retinal edema secondary to retinovascular disease in HIV. The interaction of photoreceptors with the aging RPE, as well as possible low-grade ocular inflammation causing diffuse inner retinal edema, may be the key to the progressive vision changes in HIV-positive patients without overt retinitis.