International Journal of Retina (IJRETINA) 2025.
Volume 8.
Number 2.
P-ISSN.
E-ISSN.
RETINAL THICKNESS AND RNFL EVALUATION BY
OCT IN RADIOLOGY TECHNICIANS EXPOSED TO X-RAYS WITHOUT
EYE PROTECTION IN AMAZONIAN CLINICS
Leidiana Silva de Almeida1 .
Luana Cristina Lucas Alves2 .
Jonathan Miranda Rissino3 .
Gustavo Miranda de Azevedo Ferreira4 .
Anderson Raiol Rodrigues1 .
Clyudio Eduardo Corrya Teixeira4* Nycleo de Medicina Tropical.
Universidade Federal do Pary.
Av.
Generalyssimo Deodoro 92, 66055-240 Belym.
Pary.
Brazil Universidade do Estado do Pary.
Trav.
Perebebuy 2623, 66087-670 Belym.
Pary.
Brazil Universidade da Amazynia.
Av.
Alcindo Cacela 287, 66060-902 Belym.
Pary.
Brazil Centro Universityrio do Estado do Pary.
Av.
Almirante Barroso 3775, 66013-903 Belym.
Pary.
Brazil Abstract Introduction: While the ocular effects of ionizing radiation have been widely studied, little is known about its impact on the retinas of radiology professionals exposed daily without protective This study aimed to assess potential morphological retinal changes using optical coherence tomography (OCT) in radiology technicians working without X-ray protective glasses.
Methods: A total of 11 radiology technicians routinely exposed to X-rays without eye protection were compared with 9 age-matched controls not exposed to ionizing radiation.
Subjects with systemic conditions affecting the retina .
, diabetes, hypertensio.
were excluded.
OCT scans were performed using Heidelberg Spectralis OCT to assess retinal nerve fiber layer (RNFL) thickness and global retinal thickness.
Given the small sample sizes, a descriptive comparison approach was Results: RNFL thickness was thinner in the exposed group compared to controls, particularly in the superior and nasal quadrants.
Three individuals in the exposed group showed global retinal thickness below normal limits, compared to one in the control group.
The proportion of subjects with retinal thinning was higher in the exposed group, especially in the macula and RNFL.
qualitative assessment revealed temporal macular thinning and superior RNFL thinning around the optic disc.
Conclusion: These findings suggest that chronic X-ray exposure without protective eyewear may be associated with retinal thinning and RNFL loss in radiology technicians.
Given the small sample size, further research with larger cohorts is needed to confirm long-term effects and establish preventive measures.
Keywords: Retina.
X-Rays exposure.
Radiology technicians, radiography.
Optical Coherence Tomography.
Cite This Article: ALMEIDA.
Leidiana Silva de et al.
OPTICAL COHERENCE TOMOGRAPHY ANALYSIS IN RADIOLOGY
TECHNICIANS EXPOSED TO X-RAYS WITHOUT EYE PROTECTION IN AMAZONIAN CLINICS.
International Journal of Retina, [S.
], v.
8, n.
2, p.
114, oct.
ISSN 2614-8536.
Available at:
<https://w.
com/index.
php/ijretina/article/view/327>.
Date accessed:
01 oct.
doi: https://doi.
org/10.
35479/ijretina.
Published by: INAVRS https://w.
org/ | International Journal of Retina https://ijretina.
using Optical Coherence Tomography (OCT) to INTRODUCTION Correspondence to:
Clyudio Eduardo Corrya Teixeira.
Centro Universityrio do Estado do Pary.
Av.
Almirante Barroso 3775, 66613-903 Belym.
Pary.
Brazil, teixeira@prof.
The ionizing radiation on ocular tissues have particularly regarding lens opacities and cataract formation .
- Radiotherapy-induced eye diseases are influenced by extrinsic factors such as radiation type, dose, fractionation scheme, treatment duration, and potential procedural errors.
Additionally, intrinsic retina and RNFL of radiology technicians who do not use protective glasses while operating radiography Understanding alterations is essential for assessing occupational risks and improving protective measures in radiology METHODS Participants Three groups were invited to participate in this The Non-Exposed Group (Contro.
consisted hypertension, and chemotherapy, have been linked of individuals who were not exposed to artificially to increased susceptibility to radiation-induced produced X-rays .
= 9, 4 femal.
The Exposed with ( 6 ) ocular damage evaluate potential morphological changes in the A long-term prospective study Protection Group included radiology technicians and investigating the effects of chronic X-ray exposure technologists who were exposed daily to artificially on visual function followed 35,705 radiology produced X-rays while using protective glasses.
technicians over 21 years .
3Ae2.
During this However, no participants were found for this group, period, 2,382 cases of cataracts a progressive and likely due to a lack of awareness about the effects of potentially disabling opacification of the lensAiwere ionizing radiation on ocular structures or the Interestingly, cataract occurrence was unavailability of protective equipment in their independent of workers' X-ray exposure levels .
Ae60 The Exposed without Protection Group mG.
, challenging the International Commission on consisted of radiology technicians and technologists Radiological Protection (ICRP) guidelines, which who were exposed daily to artificially produced X- suggest a minimum cumulative dose of 2 Gy to rays without using protective glasses .
= 11, 5 induce cataracts.
These findings suggest that even These professionals usually have 6 hours of low-dose chronic radiation exposure may contribute work in a hospital or clinic, but it is not uncommon to ocular damage .
) While the lens is known to be for them work in more than one place to increase highly sensitive to ionizing radiation due to its lack their income.
Amplitude of years in the profession of regenerative capacity, less is known about the ranged from 7 to 28 years.
Participants in the control effects of chronic radiation exposure on deeper and exposed groups were matched by age .
ean ocular structures, such as the retina and retinal nerve 5 A 16.
5 year.
and sex distribution to reduce fiber layer (RNFL) .
) Histopathological studies in potential confounding.
Participants were recruited animal models have shown that ionizing radiation from four hospitals and two clinics located in the city can induce retinal atrophy, vascular changes, and of Belym, capital of the State of Pary.
Brazilian neurodegeneration, but data on occupational Amazon, and informed consent was obtained after exposure in humans are scarce .
Since radiology they were informed about the studyAos objectives and professionals are exposed to low doses of X-rays the tomographic evaluation methodology .
ptical daily, it is critical to assess whether routine exposure coherence tomograph.
Exclusion criteria included individuals with conditions that could interfere with .
) This study aims to fill this gap by the studyAos objectives, such as Published by: INAVRS https://w.
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diabetes mellitus, hypertension, or exposure to a smaller p-value suggests that the measured heavy metals or organic solvents.
Additionally, all thickness is unlikely to be within the healthy, normal participants underwent a comprehensive battery of range, thereby indicating potential pathology.
neuroophthalmological tests, including a Visual Acuity Test with Snellen Optotypes.
Goldmann Applanation Tonometry.
Anterior Biomicroscopy.
Autorefraction.
Data Analysis Segment Given the small sample size .
= 9 for the control Automated group and n = 11 for the exposed grou.
, a Perimetry.
These tests ensured the absence of any descriptive comparison approach was used instead detectable neuro-ophthalmological abnormalities.
of parametric or non-parametric statistical tests to compare groups.
The analysis focused on comparing Tomographic Investigation Structural global retinal thickness and RNFL thickness between the two groups.
These parameters were assessed conducted using the Heidelberg Spectralis OCT and presented using the proportion of subjects with system (Spectrali.
Both eyes of all participants were retinal thinning, defined as macular thickness below examined to measure the RNFL and optic nerve disc 150 AAm and RNFL thickness below 100 AAm.
For Spectralis, the signal quality is addition.
Spectralis thresholds of < 150 AAm for assessed by Q score, which is an indicator of image macular thickness and < 100 AAm for RNFL thickness A Q score of 15 is the manufacturer's recommended threshold for acceptable image measurements against the equipment normative quality, and scores above 20 are considered good or database of healthy individuals.
This database excellent for measurements such as RNFL thickness.
establishes expected ranges, and measurements Lower signal strength can lead to artefactual below a certain percentile of these healthy values are thinning, so a Q score of 20 or greater is flagged as potentially abnormal.
The specific recommended to ensure reliable measurements.
thresholds of 150 AAm and 100 AAm represent values Only scans with Q score signal strength Ou 20 and below the first or fifth percentile of ageand-gender- without segmentation errors were included in the matched healthy controls, respectively, in the final analysis.
The tomographic sections were Spectralis software's internal normative data.
performed with a thickness of 2 mm, with both axial qualitative assessment of thinning patterns, such as and lateral resolution set to 5 AAm.
The measurements temporal thinning in the macula and superior RNFL included global retinal thickness, assessed as the thinning around the optic disc, was also conducted.
mean thickness across the central macula using the ETDRS grid, and RNFL thickness, measured around Ethical Considerations the optic disc at a diameter of 3.
45 mm.
When an This study was approved by the Research Ethics individual's measurement is taken, the Spectralis Committee of the Universidade da Amazynia software performs a statistical test to compare it to .
rotocol the normative database.
The pvalue is used to conducted in accordance with the Declaration of Helsinki.
assuming the person is healthy.
Assuming = 0.
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RESULTS
consistently observed in the superior region (SN to Global Retinal Thickness in the Macula NU) across both Figures 3 and 4 .
< 0.
The Tomographic higher prevalence of RNFL thinning in the exposed thickness in the macula was performed for both the group .
% vs.
11% in the control grou.
and the control group .
and the group exposed to consistent pattern of superior RNFL thinning suggest Xrays without eye protection .
, as shown that X-ray exposure without eye protection may in Figures 1 and 2.
In the control group, 3 out of 9 preferentially damage this region of the optic disc, subjects .
%) exhibited regions in both eyes with potentially increasing the risk of optic neuropathy.
retinal thickness below the clinical threshold of 150 AAm .
< 0.
, indicating significant thinning (Figure Combined Abnormalities in Global Retinal and Similarly, in the exposed group, 3 out of 11 RNFL Thickness subjects .
%) had regions in at least one eye with Figures 5 and 6 highlight individual subjects with retinal thickness below 150 AAm .
< 0.
, also abnormalities in both global retinal thickness and indicating significant thinning (Figure .
The retinal RNFL thickness.
In the control group, one subject thinning in both groups was often localized to the exhibited significant abnormalities in both eyes temporal region, as observed in the retinal thickness (Figure .
This subject had regions of global retinal While the prevalence of retinal thinning was thickness below 150 AAm in the temporal region of slightly higher in the control group .
% vs.
27%),
both eyes .
< 0.
and RNFL thickness below 100 the exposed groupAos thinning was more extensive in AAm in the superior region (ST to SN in the left eye, some subjects, particularly in the temporal region.
SN to NU in the right ey.
of both eyes .
< 0.
suggesting a potential effect of X-ray exposure on The bilateral nature of these findings suggests a macular health.
glaucoma or retinal degeneration, despite the Retinal Nerve Fiber Layer (RNFL) Thickness subject being in the control group.
In the exposed Around the Optic Disc.
group, one subject exhibited similar abnormalities.
The thickness of the retinal nerve fiber layer
(RNFL)
but only in the left eye (Figure .
This subject had regions of global retinal thickness below 150 AAm in tomography (OCT) at a 3.
45 mm diameter around the temporal region of the left eye .
< 0.
and the optic disc in the left eye of subjects from both RNFL thickness below 100 AAm in the superior region groups, as shown in Figures 3 and 4.
The results (SN to NU) of the left eye .
< 0.
The unilateral revealed a higher prevalence of RNFL thinning in the nature of the findings in this exposed group subject, exposed group compared to the control group.
combined with the consistent pattern of superior Specifically, in the control group, 1 out of 9 subjects RNFL thinning seen in other exposed group subjects .
%) had RNFL thickness below the clinical (Figures 3 and .
, suggests that X-ray exposure may threshold of 100 AAm, with the thinning localized to be associated with localized retina damage, possibly the nasal region in Figure 3 and the superior region due to the angle of exposure or individual (ST to SN) in Figure 4 .
< 0.
In contrast, in the anatomical differences exposed group, 3 out of 11 subjects .
%) had RNFL thickness below 100 AAm, with the thinning Published by: INAVRS https://w.
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Clinical Implications and Comparison The findings indicate that both the control and exposed groups exhibit retinal and RNFL thinning, but the exposed group shows a higher prevalence of RNFL thinning .
% vs.
11%) and a consistent pattern of superior RNFL damage, likely due to Xray exposure without eye protection.
The retinal thinning in the exposed group, while similar in prevalence to the control group .
% vs.
33%),
appears more extensive in some subjects, as seen in the retinal thickness maps .
Figure .
The RNFL measurements around the optic disc (Figures 3, 4, and .
show a clearer difference between the groups compared to the macular retinal thickness measurements (Figures 1 and .
, suggesting that RNFL thickness may be a more sensitive marker of radiation-induced damage.
The superior RNFL thinning in the exposed group could lead to inferior visual field defects, while the temporal retinal thinning may affect central vision if it progresses.
Both subjects with combined abnormalities (Figures 5 and .
should be monitored for functional vision changes, with the control group subject potentially requiring further evaluation for an underlying condition and the exposed group subject needing monitoring for radiation-induced damage.
Figure 1.
Tomographic evaluation of the global retinal thickness in the control group.
Of the 9 subjects, 3 had regions in both eyes with thickness below 150 AAm .
< 0.
Figure 2.
Tomographic evaluation of the global retinal thickness in the group exposed to X-rays without eye Of the 11 subjects, 3 had regions in at least one eye with thickness below 150 AAm .
< 0.
Figure 3.
Tomographic evaluation of the RNFL thickness at a 45 mm diameter around the optic disc in the left eye of control group participants .
eft colum.
and exposed group participants .
ight colum.
One subject in the control group and three in the exposed group had RNFL thickness below 100 AAm .
ircled regions, p < 0.
Figure 4.
Tomographic evaluation of the RNFL thickness at a 45 mm diameter around the optic disc in the left eye of control group participants .
eft colum.
and exposed group participants .
ight colum.
One subject in the control group and three in the exposed group had RNFL thickness below 100 AAm .
ircled regions, p < 0.
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The RNFL thinning in the exposed group was consistently localized to the superior region (SN to NU), suggesting that this area may be particularly vulnerable to radiation-induced damage.
The higher prevalence of RNFL thinning in the exposed group, along with the consistent pattern of superior RNFL involvement, indicates that X-ray exposure without eye protection Figure 5.
One subject in the control group exhibited abnormalities in both global retinal thickness .
< 0.
and RNFL thickness at a 3.
45 mm diameter around the optic disc .
< 0.
in both eyes.
may be associated with impairments in the inner retinal layers, particularly the ganglion cell axons that form the RNFL.
This is further supported by the findings in Figures 5 and 6, where one subject in each group exhibited combined abnormalities in both global retinal thickness and RNFL thickness.
In the exposed group subject, the abnormalities were unilateral .
eft eye onl.
, with temporal retinal thinning and superior RNFL thinning (Figure .
, mirroring the patterns seen in the broader exposed In contrast, the control group subject had bilateral abnormalities (Figure .
, suggesting a Figure 6.
One subject in the group exposed to Xrays without eye protection exhibited abnormalities in both global retinal thickness .
< 0.
and RNFL thickness at a 3.
45 mm diameter around the optic disc .
< 0.
, but only in the left without eye protection is associated with significant structural changes in the retina, particularly in the retinal nerve fiber layer (RNFL).
The tomographic evaluation revealed that 3 out of 11 subjects .
%) in the exposed group had global retinal thickness below 150 AAm in at least one eye (Figure .
, glaucoma or retinal degeneration, rather than an effect of radiation .
Potential Mechanisms of Radiation-Induced Damage DISCUSSION This study demonstrates that exposure to X-rays The observed RNFL thinning in the exposed group may be attributed to the vulnerability of the inner retinal layers, particularly the ganglion cells and their axons, to ionizing radiation.
The inner retinal segment, which includes ganglion cells, bipolar neurons, amacrine cells, and Myller glial cells, has a high metabolic rate and is compared to 3 out of 9 subjects .
%) in the control sensitive to oxidative stress, a well-documented group with thinning in both eyes (Figure .
More effect of ionizing radiation.
X-rays can induce notably, the RNFL thickness at a 3.
45 mm diameter DNA damage, reactive oxygen species (ROS) around the optic disc was more frequently production, and apoptosis in retinal cells, with compromised in the exposed group, with 3 out of 11 ganglion cells being particularly susceptible due subjects .
%) showing RNFL thickness below 100 AAm in the left eye, compared to only 1 out of 9 subjects .
%) in the control group (Figures 3 and .
to their long axons and high energy demands .
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The superior RNFLAos consistent involvement in .
rachytherapy delivers a localized, high dose to the the exposed group (Figures 3, 4, and .
might be tumor, whereas X-ray exposure in our study is likely related to anatomical factors, such as the density of nerve fibers in this region or the angle of Xray exposure, which could result in greater radiation absorption in the superior optic disc area .
The original hypothesis that the inner retinal layers are affected first because Auionizing radiation reaches this area firstAy is unlikely, as Xrays penetrate the entire retina uniformly due lower and more diffus.
or the timing of the measurements .
rachytherapy effects may evolve over time, leading to compensatory RNFL thickening in some region.
Additionally, the high radiation doses used in brachytherapy can cause vascular and inflammatory changes that differ from the effects of routine X-ray exposure .
In contrast.
Loganovsky .
parameters in individuals 25 years after the to its thin structure .
pproximately 200Ae300 AA.
Chernobyl accident and reported a considerable .
) Instead, the inner retinal layersAo vulnerability increase in retinal thickness .
This finding differs may be due to their cellular properties rather markedly from the thinning observed in our study, than their anatomical position.
Additionally, radiationinduced vascular changes, such as damage to the retinal pigment epithelium (RPE) or choroidal vasculature, could contribute to secondary effects on the inner retina, including RNFL thinning.
For example.
Sahoo et al.
noted that radiation retinopathy often involves vascular damage, which can lead to secondary retinal thinning over time Future studies likely due to the different exposure contexts.
The Chernobyl survivors experienced acute, high-dose radiation exposure, which may have triggered chronic inflammatory or fibrotic responses leading to retinal thickening over decades .
In contrast, our study likely involves lower-dose, routine X-ray exposure .
, occupational or medical imagin.
, which may cause more immediate cellular damage and thinning without a long-term compensatory .
) These discrepancies highlight the should investigate these mechanisms using importance of considering the radiation dose, histological analysis or biomarkers of oxidative exposure duration, and time since exposure when stress to confirm the cellular basis of the observed changes Comparison with Prior Studies The effects of ionizing radiation on the retina have been explored in other contexts, with varying Tamplin et al.
studied patients with uveal melanoma who underwent radioisotope brachytherapy and found thinning of the inner plexiform layer and ganglion cell layer, consistent with the RNFL thinning observed in the current study .
However, they also reported thickening of the RNFL in some areas, which contrasts with our findings of RNFL thinning.
This discrepancy may be due to differences in the type and dose of radiation interpreting the effects of ionizing radiation on the retina .
Clinical Implications The findings suggest that routine X-ray exposure without eye protection can lead to structural changes in the retina, particularly RNFL thinning, which may have functional consequences.
The superior RNFL thinning observed in the exposed group (Figures 3, 4, and .
corresponds to the inferior visual field, meaning that affected individuals may develop inferior visual field defects over time, a hallmark of optic neuropathies such as glaucoma or radiationinduced optic neuropathy .
Similarly, the temporal retinal thinning observed in both groups (Figures 1, 2, and .
could affect central vision Published by: INAVRS https://w.
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if it progresses, as the temporal macula contributes are needed to confirm the patterns observed.
to the central visual field .
While this study did not Additionally, the presence of retinal and RNFL assess functional outcomes, the structural changes thinning in the control group (Figures 1, 3, 4, and .
observed warrant further investigation into their suggests that some degree of thinning may be due impact on visual acuity, visual fields, and overall to natural variation or undiagnosed conditions .
visual function.
The higher prevalence of RNFL early glaucoma, retinal degeneratio.
Future thinning in the exposed group .
% vs.
11%) and the studies should include more detailed screening to consistent pattern of superior RNFL involvement exclude such conditions in control subjects, as underscore the importance of eye protection during recommended in studies of age-related eye diseases X-ray exposure, particularly in occupational settings .
, radiologists, technician.
or during medical the progression of the observed thinning and its imaging procedures Finally, longitudinal studies are needed to assess Studies of radiologic longterm impact on vision, particularly in the technologists have shown increased risks of ocular exposed group, where radiation-induced damage conditions, such as cataracts, with prolonged may worsen over time .
protective measures .
) need for The unilateral findings in the CONCLUSION exposed group subject (Figure .
suggest that In conclusion, this study provides evidence that individual factors, such as the angle of exposure or routine X-ray exposure without eye protection is baseline retinal thickness, may influence the extent associated with structural changes in the retina, of damage, highlighting the need for personalized particularly RNFL thinning in the superior region, risk assessments .
which may increase the risk of optic neuropathy and visual field defects .
The inner retinal layers.
Limitations and Future Directions especially the ganglion cells and their axons, appear This study has several limitations that should be to be particularly vulnerable to radiation-induced addressed in future research.
First, the lack of damage, likely due to their sensitivity to oxidative functional data .
, visual field testing, visual acuit.
stress and DNA damage ( .
While the findings align limits our understanding of the clinical impact of the with some prior studies showing inner retinal observed retinal and RNFL thinning.
Future studies changes after radiation exposure .
, discrepancies should include functional assessments to determine with other studies highlight the importance of whether the structural changes translate into visual exposure context in determining retinal outcomes impairment .
Second, the study did not quantify .
the dose or frequency of X-ray exposure in the measures during X-ray exposure .
) and call for exposed group, making it difficult to establish a doseresponse relationship.
Detailed exposure data, consequences, underlying mechanisms, and long including cumulative radiation dose and exposure term effects of such exposure on retinal health.
These results underscore the need for protective duration, would help clarify the risk threshold for retinal damage, as demonstrated in studies of REFERENCES