CORRELATION BETWEEN SUBFOVEAL CHOROIDAL THICKNESS AND FOVEAL THICKNESS IN THALASSEMIC PATIENTS

Alterations in optical coherence tomography and optical coherence tomography angiography findings in children with partial biotinidase deficiency

OBJECTIVES

The aim of the study was to investigate whether retinal neurovascular structural impairment in children with partial biotinidase deficiency (BD) could be detected early via optical coherence tomography (OCT) and OCT angiography (OCTA).

METHODS

Eighty patients with partial BD and 80 control cases without any known systemic or ocular diseases were enrolled in this prospective study. Retinal neurovascular structures in the macular and optic disc regions were examined in using OCT and OCTA. Data from subjects with partial BD were compared with data from healthy controls.

RESULTS

A statistically significant decrease in the vessel density (VD) was observed in both superior and inferior parts of the superficial capillary plexus (SCP) and the deep capillary plexus (DCP) in the partial BD patient group compared with the control group (p<0.05). A significant decrease in the VD was also observed in the superior and inferior peripapillary SCP-DCP regions of the optic disc area in the patients with partial BD (p<0.05). Both the superficial and deep foveal avascular zone (FAZ) areas were significantly enlarged in the partial BD group with respect to the control group (p=0.026, p=0.021 respectively).

CONCLUSIONS

In the partial BD patients, the vascular density in the macula and optic disc region is decreased in childhood, when compared to the control group. In patients with partial BD, it would be very useful to detect the early neurovascular changes that may occur during the course of the disease by means of a noninvasive technique such as OCTA.

Burden of ocular abnormalities in patients with beta thalassaemia: a cross-sectional study

INTRODUCTION

In Pakistan, the reported carrier rate of thalassaemia is estimated to be 5%-8% with 5000 new patients diagnosed every year. Several known systemic complications of beta thalassaemia major have been studied, but no studies are conducted to assess ocular complications among these patients from our population.

METHODS

It was a cross-sectional study design conducted at three private and public sector centres in Pakistan. We recruited 203, 11-17 years old children with beta thalassaemia major in our study. Frequency of overall ocular complications such as retinal pigment epithelium degeneration, visual field defects, increased retinal vascular tortuosity, lenticular opacities, anterior segment abnormality, etc among beta thalassaemia patients were verified by an ophthalmologist.

RESULTS

On univariate analysis male gender (prevalence ratio (PR): 1.023 (0.903 to 1.160), OGTT levels (PR: 0.99 (0.978 to 1.003) and serum calcium levels (PR: 0.716 (0.616 to 0.936)) were significantly associated with ocular complications. However, on multivariable analysis after adjusting for covariates we observed that the prevalence of ocular complications was 88% higher in males as compared with females. Moreover, with every one unit increase in serum calcium levels the prevalence of ocular complications were decreased by 24%.

CONCLUSION

Our study results showed that the frequency of ocular complications in beta thalassaemia children was 22.7%. Male gender was a risk factor for ocular complications among children with beta thalassaemia. However, high calcium levels among these patients were found to be protective for ocular complications.

Imaging biomarkers of leukaemic choroidopathy

PURPOSE

To longitudinally investigate choroidal and choriocapillaris perfusion metrics and the number of choroidal hyperreflective foci (HRF) in patients with acute leukaemia (AL) before and after disease remission and to correlate these metrics with systemic parameters during active disease.

METHODS

Prospective, longitudinal study of 26 eyes of 14 AL patients. All patients underwent optical coherence tomography (OCT) and OCT-angiography (OCTA) in the acute phase. Subfoveal choroidal thickness (CT), total, luminal and stromal choroidal area (TCA, LCA, SCA), choroidal vascularity index (CVI), choriocapillaris flow deficits (cFD) density, and choroidal HRF number were computed. In a subset, the measurements were repeated after AL remission. Age- and gender-matched 26 healthy controls were recruited for cross-sectional comparisons.

RESULTS

Patient's mean age was 59 ± 12 years. The TCA, LCA, SCA and choroidal HRF number were significantly higher in patients than controls (p = 0.028, p = 0.044, p = 0.024 and p = 0.001, respectively). Lower haemoglobin levels were associated with lower CT (r = 0.58, p = 0.008). Higher D-dimer values were associated with lower TCA (r = -0.52, p = 0.008), lower LCA (r = -0.50, p = 0.006), higher cFD density (r = 0.41, p = 0.044) and higher choroidal HRF number (r = 0.47, p = 0.008). The CT, TCA, SCA and choroidal HRF number significantly reduced after AL remission (p = 0.001, p = 0.047, p = 0.007 and p = 0.002 respectively). The CVI increased significantly compared to the active phase (p = 0.013).

CONCLUSION

The study demonstrates a subclinical choroidal involvement in patients with AL, with relative stromal thickening in the acute phase, and normalization after disease remission. Choroidal HRF were identified as a biomarker of leukaemic choroidopathy. Choriocapillaris and choroidal vascularity were inversely correlated with a systemic pro-coagulant state.

Optical coherence tomography findings in patients with transfusion-dependent β-thalassemia

BACKGROUND

Structural ophthalmologic findings have been reported in patients with β-thalassemia due to chronic anemia, iron overload, and iron chelation therapy toxicity in few previous studies. We aimed to investigate structural ocular findings and their relationship with hematological parameters in patients with transfusion-dependent β-thalassemia (TDT).

METHODS

In this cross-sectional study, from January 2018 to January 2019, 39 patients with TDT over the age of 18 participated. Multicolor fundus imaging, optical coherence tomography (OCT), and blue light fundus autofluorescence imaging were performed for all patients and 27 age- and sex-matched controls.

RESULTS

The mean age of patients was 28.6 ± 6.2 years. The central macular thickness and macular thicknesses in all quadrants were significantly thinner in patients than controls (P<0.05). None of the retinal nerve fiber layer (RNFL) measurements were significantly different between TDT patients and controls. There was a significantly negative correlation between hemoglobin with central macula thickness (r=-0.439, P=0.005). All measurements of macular subfield thickness were insignificantly thinner in patients with diabetes mellitus (DM) compared to the non-DM subgroup.

CONCLUSIONS

Macular thickness was significantly thinner in central macula and entire quadrants in TDT patients compared to healthy individuals; however, all RNFL measurement thicknesses were comparable between the two groups. Close monitoring of TDT patients by periodic ophthalmologic examinations with more focus on diabetic patients, patients with severe anemia and iron overload should be warranted.

Macular microvascular changes in children with transfusion-dependent beta-thalassemia

BACKGROUND

To investigate the effect of iron overload on macular perfusion among transfusion-dependent thalassemia (TDT) patients using optical coherence tomography angiography (OCTA) METHODS: The study is a prospective observational case-control study. It included 27 eyes from 27 children with transfusion-dependent β-thalassemia and 25 eyes from 25 age-matched controls. All participants were evaluated clinically and with OCTA Avanti RTVue-XR system (Optovue) to assess macular microvascular changes, by measuring vessels density (VDs) and foveal avascular zone (FAZ) area, at both superficial and deep retinal plexuses and at choriocapillaris level.

RESULTS

Foveal and parafoveal zones were significantly thinner among thalassemia patients, with significantly larger FAZ area at the level of both superficial and deep retinal plexuses when compared with control group. The thalassemia group showed significant lower values compared with the controls regarding whole-image, foveal, and parafoveal deep VD. There were significant negative correlations between serum ferritin and deep (whole image and parafoveal) VD (r =  - 0.429, P = 0.026, and r =  - 0.452, P = 0.018, respectively). Choriocapillaris VDs (whole image and foveal) showed significant negative correlations with serum ferritin levels (r =  - 0.390, P = 0.044 and r =  - 0.401, P = 0.038, respectively) CONCLUSIONS: Macular microvascular changes were detected by OCTA examination in patients with TDT, mostly due to iron overload effect, as we selected patients on iron-chelating agent with the least harmful effect on the retina. The most affected layer is the DCP. Changes at the deep layer could be used as a sensitive biomarker for early macular perfusion changes in those patients.

TRIAL REGISTRATION

Study registration number is UMIN000042657, date of registration: 2020/12/04 (retrospectively registered).

Long-Term Effects of Iron Chelating Agents on Ocular Function in Patients with Thalassemia Major

BACKGROUND

The aim of this study is to evaluate eye structures and function in patients receiving iron chelating therapy and to assess whether a correlation exists between the onset of ocular alterations and the intake of iron chelating drugs.

METHODS

A prospective cohort study was performed. Eighty-eight patients, composed of children and adults with thalassemia major (TM) who are taking or had taken iron chelating drugs (deferoxamine, deferiprone or deferasirox), have been initially enrolled in the study. The final sample featured 80 patients, including 18 children and 62 adults. These subjects received an eye examination to evaluate intraocular pressure (IOP), best corrected visual acuity (BCVA), the presence of refractive defects, cornea, anterior chamber, lens, fundus oculi, visual field and mean retinal nerve fiber layer (RNFL) thickness. Logistic regression model analysis was performed in order to assess any correlation. In addition, a literature search regarding the relation between iron chelating drugs and ocular adverse events was carried out to compare the results obtained with the evidence in the literature.

RESULTS

Logistic regression did not report a significant correlation between the intake of iron chelating drugs and the onset of anterior ocular segment alterations, lens opacities, retinal diseases, optical neuropathies, astigmatism, visual field and RNFL thickness defects. Logistic regression returned a statistically significant correlation between myopia and iron chelation therapy (p-value 0.04; OR 1.05) and also between presbyopia and total duration of therapy with deferoxamine (p-value 0.03; OR 1.21). Although intraocular pressure levels remained within the normal range, a significant correlation with the length of deferoxamine therapy has been found (p-value 0.002; association coefficient -0.12). A negative correlation between deferiprone and presbyopia has also been observed.

CONCLUSION

Iron chelation therapy is not associated with severe visual function alterations. Limitation of deferoxamine treatment can help prevent ocular complications. Deferiprone and/or deferasirox may be preferable, especially in patients over age 40 years.

Evaluation of Corneal Epithelial Thickness and Dry Eye Disease Tests in Thalassemic Adolescents

Purpose

To assess dry eye disease (DED) in thalassemic adolescents by evaluating corneal epithelial thickness (CET) and various dry eye clinical tests and correlate them to tissue iron overload.

Methods

The study included 120 Beta-thalassemia patients (11 to 18 years) and 120 matched controls. CET maps were captured using anterior segment optical coherence tomography. OSDI questionnaire was completed. Dry eye tests included Schirmer test, tear film breakup time ‎‎ (TBUT), and ocular surface staining (OSS) with fluorescein and lissamine green. We recorded serum ferritin ‎level, and liver iron concentration (LIC) measured by magnetic resonance imaging.

Results

Superior and inferior CET was thinner, while map standard deviation (MSD) was higher in thalassemics compared to controls (all P‎<0.001‎). Thalassemic group also showed higher OSDI scores‎ (P‎<0.001), shorter TBUT ‎‎(P‎<0.001‎), and higher OSS grades (P‎<0.001‎). Both superior and inferior CET was correlated positively with TBUT, and negatively with OSS (all P < 0.001). Serum ferritin and LIC showed negative correlations with CET (superior and inferior, both P< 0.001), positive correlations with MSD, P< 0.001, as well as with TBUT (P< 0.001), OSS ‎(P< 0.001), and OSDI scores (P< 0.001).

Conclusion

Thalassemic adolescents had thinner CET with higher thickness’ variability, shorter TBUT and more marked OSS‎ than controls. Correlation of higher serum ferritin and hepatic iron overload with irregular epithelial thinning and more affected dry eye tests results supports our hypothesis that high tissue iron levels could play a pivotal role in DED pathogenesis in thalassemic patients.

Choroidal Thickness Evaluation in a Transfusion-Dependent Beta-Thalassemia Greek Population

Purpose

To evaluate choroidal thickness in a group of beta-thalassemia patients as assessed by enhanced depth imaging optical coherence tomography.

Patients and Methods

This single-center, observational study involved transfusion-dependent beta-thalassemia (TD-β-thal) patients and healthy controls. One eye of each participant was included in the study. Submacular and peripapillary choroidal thickness, as well as central macular thickness and retinal nerve fiber layer thickness, were evaluated.

Results

Thirty-eight TD-β-thal patients (mean age 42 ± 10.7 years) and 22 healthy controls (mean age 40.3 ± 10.2 years) were included in the study. Subfoveal choroidal thickness was 297.4 ± 74.5 μm in the patient group and 358.4 ± 71.4 μm in the control group (p=0.003). Overall, in the submacular area, the choroid was found to be significantly thinner in the beta-thalassemia population compared to controls in all evaluated points, except for the spot located 1500 μm nasally to the fovea (p=0.093). In the peripapillary area, choroidal thickness was also significantly lower in the thalassemic population compared to the controls (nasal p=0.033, temporal p=0.01, superior p=0.01), except for the inferior quadrant (p= 0.191). We did not observe statistically significant differences in the retinal nerve fiber layer thickness and the central macular thickness between the two groups (p=0.658 and p=0.276, respectively). No correlations with hemoglobin, serum ferritin or iron levels emerged. Patients with the intermediate subtype appeared to have significantly thinner choroids than the ones with thalassemia major.

Conclusion

Our findings suggest that choroidal thickness in the submacular and peripapillary area is significantly reduced in thalassemic patients, compared to healthy individuals. Choroidal thinning in beta-thalassemia possibly reflects the effect of chronic anemia and underlying hemodynamic changes on choroidal tissue.

Retinal, choroidal and optic disc analysis in patients with Graves' disease with or without orbitopathy

PURPOSE

To compare optic disc, retinal and choroidal measurements in patients with Graves' disease with or without orbitopathy, and healthy controls.

METHODS

Optical coherence tomography and Heidelberg retinal tomography were performed in 40 patients with Graves' orbitopathy (GO), 40 subjects with Graves's disease (GD) with no sign of orbitopathy and 40 healthy controls. Degree of exophthalmos, ocular alignment, clinical activity score (CAS), choroidal thickness, retinal thickness, ganglion cell layer (GCL) thickness, disc area, cup area, rim area, cup/disc area ratio, linear cup/disc ratio and mean peripapillary retinal nerve fibre layer thickness were analysed.

RESULTS

GO patients and healthy controls significantly differ regarding mean central retinal thickness (275 ± 19 µm and 285 ± 20 µm, P = 0.017); mean central GCL thickness (14.87 ± 3.0 µm and 17.92 ± 5.02 µm, P = 0.001); mean disc area (2.00 ± 0.44 mm² and 1.72 ± 0.37 mm², P = 0.003); mean cup area (0.53 ± 0.52 mm² and 0.31 ± 0.20 mm², P = 0.003); cup/disc area ratio (0.22 ± 0.10 and 0.17 ± 0.08, P = 0.010); and linear cup/disc ratio (0.47 ± 0.15 and 0.40 ± 0.13, respectively, P = 0.011). No difference was found between patients without orbitopathy and healthy controls. No significant difference was found regarding the choroidal thickness between the three groups. There was no statistically significant relationship between retinal thickness, ganglion cell layer thickness, mean disc area, mean cup area, cup/disc area ratio, linear cup/disc ratio, CAS, exophthalmometric value and ocular alignment.

CONCLUSION

GO patients showed significant changes in foveal and GCL thickness, and optic nerve head morphology suggesting a possible influence of the orbital inflammatory process.

Spectral domain optical coherence tomography findings in Turkish sickle-cell disease and beta thalassemia major patients

Purpose

To assess probable structural changes using spectral domain optical coherence tomography (SD-OCT) on sickle-cell disease (SCD) and beta thalassemia major (B-TM) patients, without any retinal abnormalities.

Methods

This cross-sectional study included 32 B-TM, 34 SCD patients, and 44 healthy controls. One of the eyes of all participants was evaluated for SD-OCT and choroidal thickness, retinal nerve fiber layer (RNFL) thickness, central macular thickness (CMT), ganglion cell complex (GCC).

Results

Age, gender, and intraocular pressure (IOP) were not statistically different between the three groups. Hemoglobin (Hgb), hematocrite (Htc), and ferritin levels were not statistically different between the SCD and B-TM groups. Choroidal thickness at the subfoveal region was statistically higher in the control group (353.79 ± 71.93) than in the B-TM (317.41 ± 53.44) and SCD (283.21 ± 63.27) groups. In addition, it was statistically higher in the B-TM group than the SCD group (P = 0.05). CMT did not differ among the three groups, average RNFL was only significantly thinner in SCD than in controls, and GCC thickness was significantly thinner in SCD than in controls and B-TM.

Conclusion

In both diseases, we can show early structural changes even if proliferative or non-proliferative retinopathy or other ocular manifestations were not developed yet.

Outer Retinal Layers' Thickness Changes in relation to Age and Choroidal Thickness in Normal Eyes

PURPOSE

To identify and correlate age-related changes in outer retinal layers' thickness and choroidal thickness (CT) in the normal eyes using spectral-domain optical coherence tomography (SD-OCT) and to investigate factors affecting these changes.

STUDY DESIGN

Observational cross-sectional study.

SUBJECTS AND METHODS

We studied 125 healthy Egyptians between 20 and 79 years old. Patients were divided into 3 groups: group 1 (20-40 years), group 2 (40-60 years), and group 3 (>60 years). All patients had full ophthalmic examination. SD-OCT was done to measure the 9 ETDRS macular grid sectors of retinal pigment epithelium and photoreceptor outer segment (RPE-OS), outer nuclear layer and photoreceptor inner segment (ONL-IS), and choroidal thickness (CT) (by enhanced depth imaging).

RESULTS

RPE-OS was significantly thinner in group 3 than in the other 2 groups (central: P < 0.001). Moreover, the 3 groups were significantly different from each other regarding the CT (central: P < 0.001); significant thinning was noticed in the choroid with age. The 3 groups did not show significant difference concerning the ONL-IS thickness. RPE-OS and CT showed statistically significant negative correlation with age (central RPE-OS: r = -0 C.345, P < 0.001, and central CT: r = -0.725, P < 0.001) while ONL-IS showed statistically nonsignificant correlation with age (central ONL-IS: r = -0.08, P=0.376). Multiple regression analysis revealed that the most important determinant of central 1 mm RPE-OS thickness in this study was age (β = -0.087, P=0.010) rather than choroidal thinning (β = 0.001, P=0.879).

CONCLUSION

RPE-OS layer thickness shows significant thinning with increasing age, and with decrease in CT, however, age is the most determinant factor of this thinning.

Electrophysiological assessment for early detection of retinal dysfunction in β-thalassemia major patients

PURPOSE

The purpose of this study was to assess the role of various diagnostic tests in early detection of retinal changes in β-thalassemia major patients.

METHODS

Thirty-eight visually asymptomatic β-thalassemia major patients receiving regular blood transfusions and iron-chelation therapy with deferoxamine (group A, n = 13), deferasirox (group B, n = 11) or deferoxamine with deferiprone (group C, n = 14) and fourteen age- and sex- matched healthy individuals were included in the study. All participants underwent ophthalmoscopy, full-field electroretinography (ERG), visual evoked potentials (VEP), multifocal electroretinography (mfERG), fundus autofluorescence (FAF) imaging and optical coherence tomography (OCT) scans.

RESULTS

Retinal pigment epithelium changes were present in two cases. Scotopic ERG demonstrated decreased a-wave amplitude in groups A, B and C (p = 0.03, p = 0.002 and p = 0.002, respectively) and decreased b-wave amplitude in groups B and C (p = 0.002 and p = 0.01, respectively) compared to controls. Photopic ERG showed delayed b-wave latency in groups A and C (p = 0.03 and p = 0.03, respectively) ERG maximal combined response and VEP response did not differ between groups. MfERG showed reduced retinal response density in ring 1 in groups A, B, C (p < 0.001, p < 0.001, p = 0.001, respectively) and ring 2 in group B (p = 0.02) and delayed latency in ring 5 in groups A and B (p = 0.04 and p = 0.04, respectively). Abnormal FAF images appeared in three cases and OCT abnormalities in one case, whereas no changes were observed in controls (p = 0.55 and p = 1.00, respectively).

CONCLUSIONS

Full-field ERG and mfERG are more sensitive tools for detecting early retinal changes in β-thalassemia patients compared with ophthalmoscopy, VEP, FAF imaging and OCT scans.

Assessing posterior ocular structures in β-thalassemia minor

PURPOSE

The aim of this study was to investigate the effect of β-thalassemia minor on choroidal, macular, and peripapillary retinal nerve fiber layer thickness.

METHODS

To form the sample, we recruited 40 patients with β-thalassemia minor and 44 healthy participants. We used spectral-domain optical coherence tomography to take all measurements of ocular thickness, as well as measured intraocular pressure, axial length, and central corneal thickness. We later analyzed correlations of hemoglobin levels with ocular parameters.

RESULTS

A statistically significant difference emerged between patients with β-thalassemia minor and the healthy controls in terms of mean values of subfoveal, nasal, and temporal choroidal thickness (p = 0.001, p = 0.016, and p = 0.010, respectively). Except for central macular thickness, differences in paracentral macular thicknesses between the groups were also significant (superior: p < 0.001, inferior: p = 0.007, temporal: p = 0.001, and nasal: p = 0.005). Also, no statistically significant differences were noted for retinal nerve fiber layer thickness between two groups.

CONCLUSION

Mean values of subfoveal, nasal, temporal choroidal, and macular thickness for the four quadrants were significantly lower in patients with β-thalassemia minor than in healthy controls.

β-Thalassemia and ocular implications: a systematic review

Background

Beta-thalassemia is a severe genetic blood disorder caused by a mutation in the gene encoding for the beta chains of hemoglobin. Individuals with beta-thalassemia major require regular lifelong Red Blood Cell transfusions to survive. Ocular involvement is quite common and may have serious implications.

Methods

Extensive review of observational studies on beta-thalassemia, to determine the prevalence and spectrum of ocular abnormalities, by clinical examination and multimodal imaging, and to investigate risk factors for their development.

Results

Frequency of ocular involvement differs among various studies (41.3–85 %, three studies). Ocular findings in beta-thalassemia may correlate to the disease itself, iron overload or the chelating agents used. Beta-thalassemia ocular manifestations include ocular surface disease, as demonstrated by tear function parameters (two studies). Lens opacities are present in 9.3–44 % (five studies). Lenticular opacities and RPE degeneration correlated positively with use of desferrioxamine and deferriprone respectively (two studies). Ocular fundus abnormalities characteristic of pseudoxanthoma elasticum (PXE), including peau d’orange, angioid streaks, pattern dystrophy-like changes, and optic disc drusen are a consistent finding in seven studies. Patients with PXE-like fundus changes were older than patients without these fundus changes (two studies). Age (two studies) and splenectomy (one study) had the strongest association with presence of PXE-like fundus changes. Increased retinal vascular tortuosity independently of the PXE-like fundus changes was found in 11–17.9 % (three studies), which was associated with aspartate amino transferase, hemoglobin and ferritin levels (two studies). Fundus autofluorescence and electrophysiological testing (ERG and EOG) may indicate initial stages or more widespread injury than is suggested by fundus examination (two studies).

Conclusions

Beta-thalassemia may present with various signs, both structural and functional. Pseudoxanthoma elasticum like fundus changes are a frequent finding in patients with b-thalassemia. These changes increase with duration or severity of the disease. Retinal vascular tortuosity may be an additional disease manifestation related to the severity and duration of anemia and independent of the PXE-like syndrome. Patients with long-standing disease need regular ophthalmic checkups because they are at risk of developing PXE-like fundus changes and potentially of subsequent choroidal neovascularization.