Long-term follow-up of choroidal changes following COVID-19 infection: analysis of choroidal thickness and choroidal vascularity index

Ocular manifestations of COVID-19: A systematic review of current evidence

Introduction

COVID-19 caused by SARS-CoV-2, commonly presents with symptoms such as fever and shortness of breath but can also affect other organs. There is growing evidence pointing to potential eye complications. In this article, we aim to systematically review the ocular manifestations of COVID-19.

Methods

We conducted a systematic review to explore the ocular manifestations of COVID-19. We searched online databases including PubMed, Embase, Scopus, and Web of Science up to September 4, 2023. After a two-stage screening process and applying inclusion/exclusion criteria, eligible articles were advanced to the data extraction phase. The PRISMA checklist and Newcastle-Ottawa Scale (NOS) were used for quality and bias risk assessments.

Results

We selected and extracted data from 42 articles. Most of the studies were cross-sectional (n = 33), with the highest number conducted in Turkey (n = 10). The most frequent ocular manifestation was conjunctivitis, reported in 24 articles, followed by photophobia, burning, chemosis, itching, and ocular pain. Most studies reported complete recovery from these manifestations; however, one study mentioned visual loss in two patients.

Conclusion

In general, ocular manifestations of COVID-19 appear to resolve either spontaneously or with supportive treatments. For more severe cases, both medical treatment and surgery have been employed, with the outcomes suggesting that complete recoveries are attainable.

Choroidal Microvascular Alterations in COVID-19 Patients

OBJECTIVE

To evaluate alterations in the choroidal angioarchitecture of COVID-19 patients using optical Coherence Tomography (OCT) based surrogate markers.

METHODS

This prospective case-control study recruited 56 COVID-19 patients (111 eyes) and 61 healthy individuals (120 eyes). Choroidal thickness (CT) and Choroidal vascularity index (CVI) were derived from OCT images using a purpose-built automated software for choroidal image segmentation. A linear mixed model with age and gender as covariates was employed to compare CVI and CT between groups.

RESULTS

COVID-19 patients had significantly higher subfoveal (81.3um vs 86.8um, p = .02), temporal (78.8um vs 84.3um, p = .005), nasal (87.5um vs 95.1um, p = .001) and average CT (82.5um vs 88.7um, p = .001). COVID-19 patients had significantly lower subfoveal (64.0 vs 63.5, p = .02) and average CVI (63.5 vs 63.1, p = .02).

CONCLUSION

COVID-19 results in significantly thicker choroid with reduced relative vascularity. This may be attributable to increased vascular permeability secondary to inflammation, resulting in choroidal stromal edema.

How does Covid-19 affect the choroidal structures at the early post-infectious period?

PURPOSE

To evaluate choroidal thickness (CT) and choroidal vascularity index (CVI) in patients recovered from COVID-19 using enhanced depth imaging optical coherence tomography in the early postinfectious period.

METHODS

Sixty-five patients recovered from COVID-19 and 72 healthy subjects were included in the study. A full ophthalmic examination including best-corrected visual acuity (BCVA), slit lamp biomicroscopy, and dilated fundus examination was performed. CT was measured at 3 points as follows: subfoveal, 1000μm nasal and temporal to the fovea. The total choroidal area (TCA), luminal area (LA), stromal area (SA), and CVI were measured with Image-J.

RESULTS

The mean age was 39.09±11.27 years in the COVID-19 group and 39.61±11.43 years in the control group. The mean time from the first positive RT-PCR was 49.54±26.82 days (range 18-120) in the COVID-19 group. No statistically significant difference was detected between the groups with regard to axial length, spherical equivalent, and BCVA (all P>0.05). CT was found to be lower in the COVID-19 group compared to the control group in all quadrants, but this difference was not significant (all P>0.05). The mean TCA, LA, and CVI were statistically significantly reduced in the COVID-19 group (all P<0.001); however, SA showed no statistically significant difference (P=0.064).

CONCLUSIONS

In asymptomatic or mild COVID-19, CVI and LA decrease significantly, while CT thins in the early postinfectious period but not significantly.

The Effect of Corticosteroid Therapy on Choroidal Thickness in Patients With Covid-19 Infection: A Prospective, Comparative, and Observational Study

BACKGROUND

Coronavirus disease 2019 (Covid-19) has many different ocular manifestations. This study evaluates the effects of the disease and the steroid used in this disease on ocular structures.

PURPOSE

 To evaluate the effects of Covid-19 and the steroids used in the treatment of severe infection on ocular structures and choroidal thickness.

METHODS

This prospective study included 76 eyes of 76 patients who were hospitalized due to Covid-19 and 30 eyes of 30 healthy volunteering controls. Group I included 35 eyes who were hospitalized due to moderate-to-severe involvement that received steroid treatment, group II included 41 eyes with moderate involvement that did not require steroid treatment, and group III included 30 eyes with age- and gender-matched control subjects. Ophthalmological examination and imaging results of the patients obtained in the third week and third month after the diagnosis were compared between the groups.

RESULTS

Mean age of all participants was 40.2 ± 6.1 years. In the third week after the diagnosis of Covid-19, choroidal thickness in all regions (subfoveal, nasal, and temporal) was significantly greater in group I than in group II (for all, p<0.001). Moreover, choroidal thicknesses were significantly higher in group I and group II than in the control group (for all, p<0.001). In the third month, all the groups had similar choroidal thickness values (for subfoveal, nasal, and temporal; p=0.058, p=0.111, p=0.079, respectively).

CONCLUSION

Our findings showed that Covid-19 infection causes choroidal thickening by affecting the choroidal layer and that steroid treatment further increases this thickness in the acute period. In addition, the reversal of this thickening to the normal level within a period of three months indicates that the effect of the disease on the choroid is reversible.

Evaluation of retinal and choroidal parameters as neurodegeneration biomarkers in patients with post-covid-19 syndrome

BACKGROUND

To investigate the neurodegenerative effects of post-COVID-19 syndrome.

METHODS

This comparative, cross-sectional study included patients who had post-COVID-19 prolonged neurologic symptoms. The control group was selected from volunteer participants with similar age, sex, and spherical equivalent characteristics. After detailed ophthalmic examinations, spectral-domain optic coherence tomography (SD-OCT) analysis of the macula and peripapillary retinal nerve fiber layer (m-RNFL, p-RNFL respectively) were obtained. We also evaluated the choroidal parameters with the ImageJ software. Post-COVID-19 symptoms and disease severity of the patients were also questioned.

RESULTS

Thirty-four eyes of 20 patients, and 39 eyes of 23 healthy individuals were included in the study. Thinning was found in the inner superior quadrant of mRNFL (p < 0.05). More prominent and common thinning of retinal layers was observed in the ganglion cell layer (GCL) and inner plexiform layer (IPL) segments in the patient group. There was no difference between the groups in the calculated choroidal parameters (p > 0.05). In the regression models created, lung involvement was the most prominent parameter associated with thinning of the OCT layers. The other factors were male sex, and the presence of loss of taste and smell also led to deterioration in some parameters.

CONCLUSIONS

We detected an overall thinning of the GCL and IPL layers with no significant change in CMT, pRNFL, and CVI in the post-COVID-19 period, indicating the direct or indirect effect of SARS-CoV-2 on these layers, rather than a long-term neurodegenerative effect.

Evaluation of choroidal thickness with OCT in COVID-19 patients with high D-dimer levels

To evaluate retinal and choroidal thickness with optical coherence tomography (OCT) to detect retinal and choroidal pathologies in coronavirus disease 2019 (COVID-19) patients with high D-dimer levels. Thirty patients who were hospitalized in the intensive care unit due to severe acute respiratory syndrome coronavirus 2 and whose D-dimer levels were high during this period, who applied to the internal medicine outpatient clinic between 15 and 30 days after discharge, and 30 healthy volunteers with similar age and gender as the control group was included in the study. After full ophthalmological examination, central foveal and choroidal thicknesses were evaluated using optical coherence tomography. Statistical analysis of the study data demonstrated that there was no significant difference between the groups in terms of age or gender (p > 0.05). There was also no statistically significant difference between the groups in terms of central foveal thickness, central choroidal thickness, or nasal 500, nasal 1500, temporal 500, or temporal 500 micron distances (p > 0.05 for all parameters). Choroidal and retinal vascular thicknesses were not affected in the short term in COVID-19 patients hospitalized in the intensive care unit.

Ocular manifestations of recent viral pandemics: A literature review

Viral pandemics often take the world by storm, urging the medical community to prioritize the most evident systemic manifestations, often causing ocular manifestations to go unnoticed. This literature review highlights the ocular complications of the Monkeypox, SARS-CoV-2, MERS, Ebola, H1N1, and Zika viruses as the most recent viral pandemics. Research into the effects of these pandemics began immediately. Moreover, it also discusses the ocular complications of the vaccines and treatments that were used in the scope of the viral pandemics. Additionally, this review discusses the role of the eye as an important route of viral transmission, and thereafter, the International recommendations to reduce the incidence of viral transmission were mentioned. Lastly, this paper wants to lay out a platform for researchers who want to learn more about how viruses show up in the eye.

Spectral-domain optical coherence tomography assessment of retinal and choroidal changes in patients with coronavirus disease 2019: a case-control study

Objectives

This study aimed to evaluate the retinal and choroidal changes in the macular region of patients with Coronavirus Disease 2019 (COVID-19) using structural spectral-domain optical coherence tomography (SD-OCT) analysis.

Methods

This cross-sectional observational case-control study included patients recovered from COVID-19. The COVID-19 in all participants was confirmed using the reverse transcription-polymerase chain reaction (RT-PCR) technique. The participants had mild to moderate degree of disease without a history of hospitalization, steroid usage, or blood saturation below 92%. Macular SD-OCT was performed at least two weeks and up to one month after recovery from systemic COVID-19. Quantitative and qualitative changes detected by macular SD-OCT imaging were evaluated in COVID-19 recovered patients and compared with the results of age-matched normal controls.

Results

Participants in this study included 30 cases (60 eyes) and 60 healthy controls (120 eyes). In total, 17 (28.3%) eyes in patient group showed at least one abnormal finding indicated by macular SD-OCT imaging included hyperreflective lesions in different retinal layers. In addition, dilated choroidal vessels and retinal pigment epitheliopathy were evident in 41 (68.3.6%) and 4 (6.6%) eyes in patient group, respectively, and their OCT findings resembled those with pachychoroid spectrum. No statistically significant differences were observed in retinal layers or retinal volume between the two groups. The mean ± SD subfoveal choroidal thickness (SFCT) was determined at 380.3 ± 12.40 μm, which was significantly thicker than that in control group (310.7 ± 57.5 μm) (P < 0.001).

Conclusion

Regarding retinal thickness, no significant change was observed in different retina layers of patients with COVID-19; however, there were striking qualitative changes, such as hyperreflective lesions in different retinal layers. The evaluation of choroidal structure and thickness demonstrated remarkable abnormal pachyvessels and significant thickening of the SFCT but the clinical significance of these findings is unknown.

Retrobulbar Ocular Blood Flow and Choroidal Vascular Changes in Patients Recovering from COVID-19 Infection

Background

To evaluate the effects of COVID-19 infection on the ocular vascular structure including choroidal thickness and retrobulbar blood flow values in comparison with healthy subjects.

Methods

Ninety eyes of 90 patients were included in this study. Participants were divided into Group 1 (n = 30) with mild COVID-19 infection, Group 2 (n = 31) with moderate disease, and Group 3 with age- and sex-matched healthy subjects (n = 29). Choroidal thickness was measured at the subfoveal area and at 500-µm intervals nasal and temporal to the fovea up to a distance of 1500 µm, using the enhanced depth imaging (EDI) technique of spectral coherence tomography (SD-OCT). The peak systolic velocity (PSV), end diastolic velocity (EDV), resistive index (RI), and pulsatility index (PI) values of the central retinal artery (CRA) and ophthalmic artery (OA) were evaluated with color Doppler ultrasonography (CDU).

Results

The choroidal thickness was significantly thinner in Group 1 and Group 2 than in Group 3 at all measurement points (p <0.001). This difference was not present between Group 1 and Group 2 who had COVID-19 disease of different severity (p>0.05).Among the retrobulbar blood flow parameters, OA PSV value was significantly lower in Group 1 and Group 2 compared to Group 3 (p = 0.025, p = 0.016, respectively). However, the CRA PSV and EDV and OA EDV values, and the CRA and OA PI and RI values were not statistically different between the groups (p> 0.05).

Conclusion

COVID-19 infection may predispose patients to ocular vascular pathologies by affecting both choroidal and retrobulbar blood flow.