Alterations in conjunctival cytology and tear film dysfunction in patients with beta-thalassemia

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.

Evaluation of the Significance of Tear Ferning Patterns in beta-Thalassemia Patients

AIM

This study was designed to evaluate the tear film in beta-thalassemia patients using tear ferning (TF) and phenol red thread (PRT) tests.

METHODS

Forty beta-thalassemia patients, aged 18 - 38 years (25.7 ± 6.0 years), along with a control group of 40 age-matched subjects with healthy eyes completed the study. All subjects completed the ocular surface disease index (OSDI) first, followed by the TF and PRT tests with a 5-minute gap between the tests.

RESULTS

Significant differences (Wilcoxon test, p < 0.05) were observed between the beta-thalassemia and control groups in all scores. Among beta-thalassemia patients, OSDI scores indicated eye dryness in 35 subjects (87.5%). PRT showed dryness in 31 subjects (77.5%) in the right and left eyes, and the TF grades were ≥ 2 for the tears collected from 35 subjects (87.5%). There was a strong correlation (r = 0.851, p = 0.001) between the PRT measurements in the right and left eyes. There was a medium correlation between OSDI and TF scores (r = 0.309, p = 0.026) and between OSDI and age (r = 0.365, p = 0.010). Age had a moderate negative correlation (r = - 0.328, p = 0.019) with the PRT obtained from the right eye.

CONCLUSION

Significant ocular dryness symptom was observed in beta-thalassemia patients, based on the scores collected from TF and PRT tests. Beta-thalassemia patients develop dry eyes, possibly due to several factors, including reduced tear secretion. Therefore, it is important to regularly evaluate both the quality and quantity of tears in patients with beta-thalassemia.

Anterior Chamber Angle, Intraocular Pressure, and Globe Biometric Parameters in the Children with &beta;-Thalassemia Major

Background

To evaluate the intraocular pressure (IOP), anterior chamber angle (ACA), and globe biometric parameters in β-thalassemia major children and the correlations of these changes.

Materials and methods

Eighty-four eyes were included (42 eyes of thalassemia patients and 42 eyes of control). All participates underwent head circumference and height measurements, full ophthalmic examination, anterior segment optical coherence tomography (AS-OCT), and A-scan biometry.

Results

The temporal angle of anterior chamber (T-ACA) was significantly narrower in thalassemia patients with p value = 0.008. While the nasal angle showed a nonsignificant narrowing with p value = 0.153. This narrowing was positively correlated with the height, and negatively correlated with the head circumference. Intraocular pressure was statistically higher in thalassemia patients with p value = 0.000. The increased IOP was positively correlated with the head circumference and the lens thickness (LT) and negatively correlated with T-ACA, axial length (AL), vitreous chamber depth (VCD), and anterior chamber depth (ACD). Axial length, ACD, and VCD significantly decreased with p value = 0.000 for all with a positive correlation with the height and a negative correlation with the head circumference. The LT increased in thalassemia group with p value = 0.000. This increase was positively correlated with the head circumference and negatively with the height. Also, there was steeper corneal curvature in thalassemia group with p value = 0.023 and 0.015 (for K₁ and K₂, respectively). No significant change was observed in corneal thickness in both groups with p value = 0.810.

Conclusion

Narrower T-ACA, increased IOP, shorter (AL, VCD, and ACD), steeper corneal curvature, and thicker lens were found in thalassemia patients.

How to cite this article

El-Haddad NSM. Anterior Chamber Angle, Intraocular Pressure, and Globe Biometric Parameters in the Children with β-Thalassemia Major. J Curr Glaucoma Pract 2020;14(1):30–36.

Ocular abnormalities in beta thalassemia patients: prevalence, impact, and management strategies

BACKGROUND

Beta thalassemia (β-thalassemia) is a hereditary disease caused by defective globin synthesis and can be classified into three categories of minor (β-TMi), intermedia (β-TI), and major (β-TM) thalassemia. The aim of our study is to investigate the effects of β-thalassemia and its treatment methods on different parts of the eye and how early-diagnostic methods of ocular complications in this disorder would prevent further ocular complications in these patients by immediate treatment and diet change.

METHODS

We developed a search strategy using a combination of the words Beta thalassemia, Ocular abnormalities, Iron overload, chelation therapy to identify all articles from PubMed, Web of Science, Scopus, and Google Scholar up to December 2018. To find more articles and to ensure that databases were thoroughly searched, the reference lists of selected articles were also reviewed.

RESULTS

Complications such as retinopathy, crystalline lens opacification, color vision deficiency, nyctalopia, depressed visual field, reduced visual acuity, reduced contrast sensitivity, amplitude reduction in a-wave and b-wave in Electroretinography (ERG), and decrease in the Arden ratio in Electrooculography (EOG) have all been reported in β-thalassemia patients undergoing chelation therapy.

CONCLUSION

Ocular problems due to β-thalassemia may be a result of anemia, iron overload in the body tissue, side effects of iron chelators, and the complications of orbital bone marrow expansion.

Ocular abnormalities in multi-transfused beta-thalassemia patients

AIMS

The aim of this study was to assess ocular changes in thalassemia patients who have received multiple transfusions and chelate binding therapy in order to avoid iron accumulation.

SETTINGS AND DESIGN

A cross-sectional study.

SUBJECTS AND METHODS

A total of 54 thalassemia major patients were selected as case group, and 54 age- and sex-matched healthy subjects were regarded as a control group. Ocular examination included visual acuity, refraction testing, slit lamp examination, funduscopy, tonometry, perimetry, tear break-up time test, and color vision testing were performed for all the participants. We computed the frequency and duration of blood transfusion, the mean serum ferritin level, pretransfusion hemoglobin concentration, and type, duration, and daily dose of chelation therapy for thalassemia patients based on their records.

STATISTICAL ANALYSIS USED

All data analysis was performed using SPSS, version 19.

RESULTS

All the thalassemic patients were asymptomatic, but abnormal ocular findings (dry eye (33.3%), cataract (10.2%), retinal pigment epithelium degeneration (16.7%), color vision deficiency (3.7%), and visual field defects (33.7%)) were seen in 68.5% of thalassemic group. The prevalence of ocular abnormalities in normal group was 19.4%, which was significantly lower than that in thalassemia patients (P = 0.000). No significant correlation was found between ocular abnormalities and mean serum ferritin level (P = 0.627) and mean hemoglobin concentration (P = 0.143). Correlation of number of blood transfusion with the presence of ocular abnormalities was found to be statistically significant (P = 0.005).

CONCLUSIONS

As life expectancy for beta-thalassemia patients extends, regular ophthalmological evaluation to detect early changes in their ocular system is recommended.

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.

Ocular findings in children with thalassemia major in Eastern Mediterranean

AIM

To investigate ophthalmologic findings in children with thalassemia major (TM) and compare the findings with healthy controls.

METHODS

In a cross-sectional study, 43 children with thalassemia major from pediatric hematology outpatient clinics from two university hospitals and age/sex matched 47 healthy children were included in the study. After a complete ophthalmic examination, tear function tests including the Schirmer test, fluorescein tear break-up time (BUT), ultrasound pachymetry, and axial length measurement were performed. Obtained data was recorded for statistical analysis and the values of right eyes were compared between groups.

RESULTS

The mean best corrected visual acuity was 1.34±0.75 in TM and 1.08±0.28 in controls. It was found lower than 0.1 logMAR unit in 10 (23.2%) children with TM and 2 (4.2%) in controls, and the difference was statistically significant (P<0.05). The mean central corneal thickness was 540±26.95 in children with TM and 536.98±20.45µm in controls (P>0.05). The mean axial length was 22.53±0.50 in TM and 22.57±0.43mm in the control group. The mean Schirmer test score was 19.94±6.91 in TM and 24.22±3.95mm in the control group (P<0.01). The mean BUT score was 9.62±1.28 in TM and 9.73±0.6s in the control group (P>0.05).

CONCLUSION

In TM, while corneal thickness, axial length, and BUT are close to controls, the Schirmer scores are less than normal. The study revealed that TM may be affected by the tear function and visual acuity.

Ocular refractive and biometric characteristics in patients with thalassaemia major

BACKGROUND

Thalassaemia major is associated with characteristic findings in craniofacial bony structures and thereby may render abnormal bony orbit and subsequently distinctive ocular biometry. The purpose of the present study was to evaluate the ocular refractive and biometric characteristics in patients with thalassaemia major.

METHODS

This case-controlled study comprised 94 eyes of 47 patients with thalassaemia major and 88 eyes of 44 age- and sex-matched healthy control subjects. All participants had a complete ocular examination including slitlamp biomicroscopy, fundoscopy, ocular biometry, keratometry, refraction and analysis using Fourier transformation.

RESULTS

There were no significant differences in spherical equivalent (p = 0.66) and total astigmatism (p = 0.83) between groups. Mean uncorrected vision and visual acuities (logMar) were similar (p = 0.32 and p = 0.71, respectively). Compared with controls, thalassaemic patients had a shorter axial length (23.01 ± 0.12 [SEM] mm versus 23.46 ± 0.12 mm, p = 0.035), thicker crystalline lens (4.01 ± 0.11 mm versus 3.87 ± 0.1 mm, p = 0.046) and steeper average keratometry (44.02 ± 0.24 D versus 43.44 ± 0.24, p = 0.03). Fifty-seven per cent of thalassaemic patients had against-the-rule astigmatism (total), while 64.6 per cent of controls showed a with-the-rule pattern (p < 0.05). These patterns were also found for corneal astigmatism. The magnitudes of total, corneal and lenticular astigmatism were similar among groups. Regression analysis showed significant correlation between corneal (J0 and J45) and total (J0 and J45) astigmatism. The correlations were less prominent between lenticular and total J0 and J45. The mean intraocular pressure was 14.68 ± 0.27 mmHg and 13.3 ± 0.26 mmHg in the thalassaemia and control groups, respectively (p < 0.001). Six eyes (12.8 per cent) of four patients in the thalassaemia group had posterior subcapsular cataract, while the condition had not been observed in controls (p = 0.049).

CONCLUSIONS

Shorter axial length, thicker lens, steeper corneal curvature and more against-the-rule pattern were characteristic findings in patients with thalassaemia major.