Variability of choroidal and retinal thicknesses in healthy eyes using swept-source optical coherence tomography - implications for designing clinical trials

Macular choroidal thickness, volume, and vascularity index in patients with systemic sclerosis

PURPOSE

The aim of this study was to investigate choroidal parameters in patients with systemic sclerosis (SSc) using enhanced depth imaging spectral-domain optical coherence tomography (EDI-SD-OCT) and to determine their relationships with clinical variables and ocular features.

METHODS

Thirty-three patients with SSc and 40 controls were enrolled. The groups did not differ with regard to age, sex, and axial length. The mean choroidal thickness and volume were obtained in each conventional Early Treatment of Diabetic Retinopathy Study grid subfield. The choroidal vascularity index (CVI), which provides a quantitative analysis of vasculature by calculating the proportion of the luminal area (LA) to the total choroidal area (TCA), was determined.

RESULTS

Lower choroidal thickness and volume were observed in the SSc group. The CVI was significantly higher in SSc patients, whereas the TCA, LA, and stromal area were significantly lower in the SSc group; however, the significant difference of the stromal component was more pronounced than that of the luminal component. Regression analyses did not identify any clinical factors associated with the CVI (except Ca-blocker use), central macular thickness, or volume. No significant differences in choroidal parameters were found within the SSc subtypes (diffuse cutaneous systemic sclerosis (dcSSc) vs. limited cutaneous systemic sclerosis (lcSSc)), or between eyes stratified according to SSc pattern (early, active, or late) using nailfold capillaroscopy (p > 0.05 for all).

CONCLUSION

Our results, with notably higher CVI values, may shed new light on choroidal impairment in patients with SSc. Stromal involvement appeared to dominate the vascular component.

Evaluation of choroidal thickness and ocular manifestations in lipoid proteinosis

PURPOSE

To assess choroidal thickness in patients with lipoid proteinosis versus healthy subjects using enhanced depth imaging optical coherence tomography.

METHODS

Twenty eyes of 20 patients and the same number of age and sex-matched healthy individuals were enrolled. Comprehensive ocular examinations including measurement of best-corrected visual acuity, spherical equivalent values of refractive errors, and axial length were performed. Choroidal thickness at three points (subfoveal, 500 µm nasal and temporal regions) were measured automatically using MATLAB software.

RESULTS

The mean age was 15.68 ± 5.98 years in the patient group and 16.48 ± 5.69 years in the control group. Mean choroidal thickness was statistically significantly thicker at each point in patients with lipoid proteinosis compared to the healthy controls: subfoveal, temporal and nasal choroidal thickness measurements were 425.65 ± 51.42, 380.20 ± 69.66, 334.05 ± 49.98 µm in the study group; 346.15 ± 47.76, 330.15 ± 44.35, 298.95 ± 44.21 µm in the control group, respectively (P < 0.05).

CONCLUSION

Patients with lipoid proteinosis have thicker choroid compared to control eyes. Hyalin deposition and ensuing potential inflammation in the disease process may explain this finding.

Late-Onset Retinal Degeneration: Clinical Perspectives

Late-onset retinal degeneration (L-ORD) is a type of retinal dystrophy marked by nyctalopia and subretinal pigment epithelium deposits, which eventually promote retinal atrophy with final visual compromise. L-ORD may also present with changes in the anterior segment, notably long anterior zonules and iris atrophy, distinguishing it from other inherited eye conditions. Although it can clinically simulate age-related macular degeneration, L-ORD has a different course of progression and prognosis, requiring adequate diagnosis for patient counseling. This review summarizes the main clinical, genetic, pathophysiological, diagnostic, and therapeutic aspects of L-ORD to help ophthalmologists identify and manage this rare ocular disease.

Aqueous humor inflammatory cytokine levels and choroidal thickness in patients with macular edema associated with branch retinal vein occlusion

PURPOSE

We aimed to investigate the association between subfoveal choroidal thickness (SCT) and the level of aqueous humor (AH) inflammatory cytokines in patients with macular edema (ME) associated with branch retinal vein occlusion (BRVO).

METHODS

Twenty-eight eyes of 28 BRVO ME patients who underwent intravitreal injection treatment (ranibizumab, bevacizumab, or dexamethasone implant) were prospectively recruited. The concentrations of vascular endothelial growth factor (VEGF)-A and inflammatory cytokines were measured from AH samples. We analyzed clinical factors associated with visual gain or the degree of central macular thickness (CMT) decrease and the association between SCT and inflammatory cytokine levels.

RESULTS

On multiple linear regression analysis, the AH interleukin (IL)-8 level was significantly associated with visual gain and CMT reduction at 6 months. Age, systemic hypertension, and AH monocyte chemo-attractant protein 1 level showed a significant association with baseline SCT, and VEGF-A showed a significant association with baseline SCT ratio (BRVO eye SCT/fellow eye SCT). Those with thick SCT showed a higher level of AH soluble VEGF receptors 2 and IL-8 and showed better visual gain and greater CMT reduction at 2 and 6 months compared to the thin SCT group.

CONCLUSIONS

The level of AH inflammatory cytokines was significantly associated with the ischemic status of the retina, treatment outcomes, and SCT in BRVO ME patients. Thick baseline SCT might be a predictive sign for better treatment outcomes in BRVO ME patients which are thought to be related to a higher level of intraocular inflammatory cytokines in these patients.

Choroidal changes in intermediate age-related macular degeneration patients with drusen or pseudodrusen

Reticular pseudodrusen are associated with a thinner choroid. The aim of our study was to determine the differences in central choroidal thickness and choriocapillaris vascular flow area between eyes with and without reticular pseudodrusen using swept-source optical coherence tomography and swept-source optical coherence tomography angiography. We conducted a retrospective case control study which included 27 eyes from 27 consecutive patients with intermediate age-related macular degeneration and 17 eyes from 17 healthy participants. Complete ophthalmic examinations were carried out including axial length measurements; fundus color retinography; fundus autofluorescence; swept-source optical coherence tomography and swept-source optical coherence tomography angiography; central choroidal thickness and choriocapillaris vascular flow area. Patients were classified as no reticular pseudodrusen, mild reticular pseudodrusen, and severe reticular pseudodrusen. Mean central choroidal thickness in patients exhibiting severe reticular pseudodrusen (110 ± 56 μm) was significantly smaller than in patients with no reticular pseudodrusen (201 ± 76 μm, p < 0.01). Mean choriocapillaris vascular flow area in severe reticular pseudodrusen patients (45.2% ± 3.0%) was also significantly less than in patients with no (47.9% ± 1.6%, p < 0.001) and mild reticular pseudodrusen (47.7% ± 1.0%, p < 0.05). Stepwise multiple regression models confirmed the association of reticular pseudodrusen with central choroidal thickness (p < 0.001) and choriocapillaris vascular flow area (p < 0.01) even after accounting for age, axial length, and refractive error. Soft drusen were not associated with changes in either central choroidal thickness (p = 0.13) nor choriocapillaris vascular flow area (p = 0.29). A significant, positive relationship was found between central choroidal thickness and choriocapillaris vascular flow area (r = 0.44, p = 0.01). Therefore, both central choroidal thickness and choriocapillaris vascular flow area are decreased in eyes with reticular pseudodrusen, as compared to healthy eyes and intermediate age-related macular degeneration eyes not exhibiting reticular pseudodrusen. In addition, central choroidal thickness and choriocapillaris vascular flow area are related, and the reduction of either is directly associated to the severity of reticular pseudodrusen. Further studies are needed to assess the clinical significance of these findings.

Choroidal and retinal thickness in systemic autoimmune and inflammatory diseases: A review

To identify the risk of relapse and subclinical inflammatory stages of systemic autoimmune diseases, new tools are needed. In the recent years, choroidal thickness and retinal thickness measured with ocular coherence tomography (OCT) have been proposed as an inflammatory marker for different systemic diseases, especially for conditions with a vascular component. Our aim in this article is to review the literature regarding the role of choroidal and retinal thickness as a potential inflammatory marker in systemic autoimmune and inflammatory diseases measured by OCT. Current literature suggests that the choroid of patients thickens in active phases of inflammatory diseases with vascular involvement. This pattern is observed in lupus, systemic sclerosis, Behçet disease, spondylitis, and familial Mediterranean fever. Choroidal thickness may decrease with biological treatments, along with systemic inflammation. Repeated flares and long-term disease, however, may thin the choroid, as a result of prolonged insult to the microvasculature and subsequent atrophy. Less is known about the effect of these diseases on retinal thickness. In summary, choroidal and retinal thickness measured by OCT may be promising markers for inflammation in systemic autoimmune and inflammatory diseases; however, more studies are warranted before generalizing choroidal thickness measurements by OCT as a marker for disease activity. The role of retinal thickness is more unclear due to a lack of studies in this field.