Original Article
Clinical and Autofluorescence Findings in Eyes with
Pinguecula and Pterygium
Amir-Hooshang Beheshtnejad1, MD; Hamed Ghassemi2, MD; Hossein Abdolkhalegh2, MD; Mehrnaz
Atighehchian2, MD
1Department of Ophthalmology, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
2Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
ORCID:
Amir-Hooshang Beheshtnejad: http://orcid.org/0000-0003-2633-268X
Mehrnaz Atighehchian: http://orcid.org/0000-0002-6357-1033C
Abstract
Purpose: To assess the autofluorescence size and properties of pterygium and pinguecula
by anterior segment autofluorescence (AS-AF) imaging and demonstrate the difference of
autofluorescence size presented in AS-AF imaging compared to the extend size of the
conjunctival lesion measured by anterior segment slit-lamp photography (AS-SLE).
Methods: Twenty-five patients with primary pterygium and twenty-five with pinguecula were
included in the study. In addition, 25 normal subjects were also enrolled as the control group. The
AS-AF characteristics of pterygium and pinguecula lesions were analyzed. The size of lesions
displayed in the AS-SLE photography versus the AS-AF images were also compared. AS-AF
images were obtained using a Heidelberg retina angiograph which focused on the anterior
segment. AS-SLE photography was acquired using a digital imaging system (BX900 HAAG-
STREIT).
Results: There were 44 (58.7%) male and 31 (41.3%) female patients; 19 (76%) and 20
(80%) patients had bilateral pterygium and pinguecula, respectively. All pinguecula lesions
reflected hyperautofluorescence pattern in the AS-AF imaging. In 24 (96%) patients, the
hyperautofluoresecence pattern was larger than the size of the clinical lesions displayed
with the AS-SLE photography. Twenty-one (84%) patients with pterygium reflected a
hyperautofluorescence pattern in AS-AF images; in one (4%) patient, the hyperautofluorescence
pattern was larger than the clinical lesion size and four (16%) patients had no autofluorescence
patterns in the AS-AF images. In the control group, in 14 (56%) subjects, a hypoautofluorescent
pattern was revealed in the conjunctiva in AS-AF images. However, in 11 (44%) patients,
hyperautofluorescence patterns were detected.
Conclusion: AS-AF is a useful modality to monitor vascularization in conjunctival lesions.
Pingueculae and pterygium show hyperautofluorescence in AS-AF imaging. The real size of the
pinguecula lesions may be estimated with AS-AF characteristics, mostly presenting larger than
the area size in AS-SLE photography. The autofluorescence size of the pterygium is smaller than
the extent of visible pterygium in slit-lamp photography.
Keywords: Autofluorescence; Pinguecula; Pterygium
J Ophthalmic Vis Res 2023; 18 (3): 260–266
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Autofluorescence of Pingueculae and Pterygia; Beheshtnejad et al
INTRODUCTION
A pterygium is an inflammatory ocular surface
disease and triangular fibrovascular growth that
emanates from the bulbar conjunctiva and crosses
the cornea at the interpalpebral fissure on the nasal
or temporal sides of the eye; mostly affecting the
nasal rather than the temporal side.[1–4]
A pinguecula is a benign yellowish protruding
lesion adjacent to the limbus that does not cross
the cornea and may be visible on both sides of
the cornea but is more often seen on the nasal
side.[5] The pathogenesis of these conjunctival
lesions remains indistinctive. These degenerative
conditions are affected by several intrinsic and
extrinsic factors such as age, wind, solar, and
ultraviolet radiation exposure.[5, 6] Fluorescence
is the ability of specific molecules to radiate light
energy of a longer wavelength when stimulated by
a shorter wavelength light without injecting dye.[7]
Recently, fundus autofluorescence (AF) has been
a beneficial imaging modality for the diagnosis of
different retinal disorders. Retinal autofluorescence
imaging is based on the stimulated emission of light
from lipofuscin and is a noninvasive retinal pigment
epithelium examination technique.[7–10] The size
of pinguecula can be evaluated by AF features,
and often has a larger autofluorescence area size
in the AF imaging than the visible lesion size in
clinical examination by slit-lamp biomicroscopy.[5, 7]
To the best of our knowledge, there have been a
few reports on anterior segment autofluorescence
(AS-AF) imaging for evaluating anterior segment
disorders. The previous studies did not compare
autofluorescence patterns between pterygium and
pinguecula;[7] therefore, in this study, we aimed
Correspondence to:
Hamed Ghassemi, MD. Eye Research Center, Farabi Eye
Hospital, Tehran University of Medical Sciences, Tehran
13366, Iran.
Email: h_ghassemi@tums.ac.ir
Mehrnaz Atighehchian, MD. Eye Research Center, Farabi
Eye Hospital, Tehran University of Medical Sciences,
Tehran 13366, Iran.
Email: mehrnaz.atighehchian@gmail.com
Received: 20-05-2022 Accepted: 04-01-2023
Access this article online
Website: https://knepublishing.com/index.php/JOVR
DOI: 10.18502/jovr.v18i3.13773
to assess the discrepancy of AS-AF properties on
these two wide-spread conjunctival diseases, and
compare the AS-AF results to actual lesions’ size
displayed by slit-lamp photography.
METHODS
Patients
The patients included in this study were those who
visited the ocular surface eye clinic, Farabi Eye
Hospital, Tehran University of Medical Sciences.
Patients with pinguecula or primary pterygium with
no other ocular surface disease were included in
this study. Seventy-five patients (31 women, 44
men) between the ages of 21 and 73 years were
enrolled, of whom 25 patients were diagnosed
with pterygium and 25 were diagnosed with
pingueculae. In addition, 25 healthy subjects with
neither pterygium nor pinguecula were considered
as a control group. Each patient underwent
general ophthalmic examination including visual
acuity assessment, slit-lamp biomicroscopy,
intraocular pressure measurement with Goldmann
applanation tonometry, and posterior segments
examination with indirect ophthalmoscopy.
Inclusion criteria were confirmation of either
having primary pterygium or pinguecula through
slit-lamp biomicroscopy, and patients being older
than 21 years. In bilateral cases, only one eye
with primary pterygium with less inflammatory
features and more advance stage was considered.
Pterygium were classified into three stages
according to the following method suggested by
Yang et al – Stage I, the head of the pterygium
does not reach the midline between the limbus
and pupillary margin; Stage II, the head of the
pterygium passes the midline but does not reach
the pupil; and Stage III, the head of the pterygium
passes the pupillary margin.[1] The inflammation
was clinically graded according to hyperemia in
This is an open access article distributed under the Creative Commons
Attribution License, which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly cited.
How to cite this article: Beheshtnejad AH, Ghassemi H,
Abdolkhalegh H, Atighehchian M. Clinical and Autofluorescence
Findings in Eyes with Pinguecula and Pterygium. J Ophthalmic Vis
Res 2023;18:260–266.
JOURNAL OF OPHTHALMIC AND VISION RESEARCH Volume 18, Issue 3, July-Sept 2023 261
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Autofluorescence of Pingueculae and Pterygia; Beheshtnejad et al
A B
Figure 1. (A) Normal conjunctiva in slit-lamp photography. (B) Hypoautofluorescence pattern at the temporal area in AS-AF imaging.
A B
Figure 2. (A) Pinguecula at the temporal side in slit-lamp photography. (B) Hyperautofluoresecence pattern at the temporal side
in AS-AF. The size of the autofluorescence area is larger than the size of the visible pinguecula in slit-lamp photography.
A B
Figure 3. Pterygium at the nasal side of the left eye in slit-lamp photography. (B) Faint punctuate hyperautofluoresecence pattern
is seen at the nasal side in AS-AF imaging. The size of the autofluorescence area of pterygium is smaller than the visible pterygium
size in slit-lamp photography.
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Autofluorescence of Pingueculae and Pterygia; Beheshtnejad et al
A B
Figure 4. (A) Pterygium. (B) Complete hypoautofluorescence pattern in AS-AF imaging.
Table 1. The comparison of lesions size between slit-lamp photography and AS-AF imaging.
Subjects Mean slit-lamp
photography
area (mm2)
Mean AS-AF
imaging1area
(mm2)
Std. D2
slit-lamp
photography
area (mm2)
Std. D AS-AF
imaging area
(mm2)
Difference 95% Confidence
Interval of the
Difference
P-value
Pinguecula 10.128 19.320 4.149 7.795 –9.192 –11.446 to –6.937 <0.001
Pterygium 50.924 7.194 21.286 5.461 43.730 33.570 to 53.889 <0.001
Normal 0 0.388 0 0.526 –0.388 –0.605 to –0.170 0.001
AS-AF imaging, anterior segment autofluorescence imaging; mm2, square millimeter; Std, standard deviation
P-value < 0.05
the site of pterygium excision zone as follows: 0 =
none, 1 = mild, 2 = moderate, and 3 = severe.[4]
Exclusion criteria were a history of topical
medication usage other than artificial tears one
month before the study, recurrent pterygium,
keratitis, atopic keratoconjunctivitis, inflammatory
conjunctival disorders, previous ocular surface
surgery, severe dry eye disease, abnormal
eyelid function, conjunctival scarring, and
symblepharon.
This study adhered to the tenets of the
Declaration of Helsinki and the protocol
of the study was approved by the Ethics
Committee of Tehran University of Medical
Sciences, Tehran, Iran; the approval number was
IR.TUMS.VCR.REC.1396.4797. Informed consent
was obtained from all patients and demographic
characteristics of the patients including age, sex,
family history, and, outdoor period time were
considered.
Slit-lamp Photography and AS-AF Image
Techniques and Analysis
Anterior segment slit-lamp photography was
obtained using a digital imaging system (BX900
HAAG-STREIT). A confocal scanning laser
ophthalmoscope (Heidelberg Retina Angiography
HRA2, Heidelberg) was used for the evaluation of
anterior segment AF images. AS-AF imaging can
be used for determining the size of conjunctival
lesions such as pterygium and pinguecula. This
device uses argon blue laser stimulating light
with a 488 nm wavelength and a barrier filter that
allows the passage of stimulating lights >500
nm wavelength. The focus on the conjunctiva is
obtained with the infrared mode of this device and
AF images are saved in fluorescein angiogram
mode without using fluorescein dye.[7]
In the present study, the pinguecula and
pterygium lesions’ size at the temporal or nasal of
the cornea in slit-lamp photography was compared
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Autofluorescence of Pingueculae and Pterygia; Beheshtnejad et al
with the autofluorescence size of the lesions
displayed in AS-AF. The autofluorescence region
size in AS-AF was analyzed and measured in mm2
with IMAGE J software.
Statistical Analysis
This study is a cross-sectional study. Statistical
analysis was performed using SPSS software
version 17. The correlation between the lesion
size in AS-AF and slit-lamp photography was
evaluated using a Pearson correlation test. Chi-
square test was used for the study of the qualitative
results and independent t-test was used for
evaluating the quantitative findings. A P-value <
0.05 was considered as statistically significant.
Discriminated analysis was used to evaluate the
role of confounding factors.
RESULTS
A total of 75 patients were included in the study.
Of these, 25 patients had primary pterygium and
25 had pinguecula. The remaining 25 patients
neither had pterygium nor pinguecula and were
considered as the control group.
On slit-lamp biomicroscopy, 24 (96%) patients
had nasal pterygium and only 1 (4%) patient had
temporal pterygium. Pinguecula was detected on
the nasal and temporal sides in 13 (52%) and 12
(48%) patients, respectively. Moreover, 19 (76%)
patients with pterygium and 20 (80%) patients with
pinguecula had bilateral lesions. The mean age
of patients was 46.89 ± 1.37 years (range: 21–73
years). Overall, 44 (58.7%) patients were males and
31 (41.3%) were females. There were 16 men and 9
women who had both pinguecula and pterygium.
While the prevalence of both lesions was slightly
more in men than in women, there was no
statically significant correlation between sex and
presentation of these lesions (P = 0.41).
Comparison of lesions’ size between slit-lamp
photography and AS-AF imaging
A statistically significant correlation was
observed between the lesions’ size displayed
in slit-lamp photography and the autofluorescence
area size displayed in AS-AF imaging for pterygium
and pinguecula.
In 25 patients with pinguecula, the mean size
of pinguecula lesions in slit-lamp photography
was 10.128 mm2 and the mean size of the
autofluorescence area displayed through the AS-
AF imaging was 19.32 mm2. The difference was
–9.19 mm2 (95% CI: –11.44 to –6.94, P < 0.001).
So, the mean size of the autofluorescence area
displayed in AS- AF imaging was 9.19 mm2 larger
than the mean size of the pinguecula displayed in
slit-lamp photography (P = 0.001).
In 25 patients with pterygium, the mean size
of the pterygium lesions displayed in slit-lamp
photography versus the autofluorescence area
displayed in AS-AF imaging was 50.92 mm2 and
7.19 mm2, respectively. The difference was 43.73
mm2 (95% CI: 33.57 to 53.88, P < 0.001). So, the
mean size of the autofluorescence area displayed
in the AS-AF imaging was 43.73 mm2 smaller than
the mean size of the pterygium displayed in slit-
lamp photography (P = 0.001).
In addition, in 14 (56%) participants with healthy
conjunctiva and intact vessels who did not have
either pinguecula or pterygium, their conjunctiva
revealed a hypoautofluorescence pattern in the
AS-AF images [Figure 1]. However, in 11 (44%)
subjects, a hyperautofluorescence pattern was
detected. The mean size of the autofluorescence
area of the healthy conjunctiva was 0.388 mm2.
The difference was 0.388 mm2 (95% CI: –0.60 to
–0.17, P < 0.001). So, the mean size of the healthy
conjunctiva reflected in the autofluorescence area
in normal subjects in the AS-AF imaging was 0.388
mm2 larger than the normal conjunctiva images
reflected in slit-lamp photography (P = 0.001).
Table 1 shows the comparison of lesion sizes
displayed between slit-lamp photography and AS-
AF imaging.
Comparative images between slit-lamp
photography and AS-AF imaging
The pinguecula lesions were revealed as
hyperautofluorescence pattern in the AS-
AF images in all patients. This well-defined
autofluorescence area in 24 (96%) patients
displayed a greater size than the visible part
extension of pinguecula lesions displayed on
slit-lamp photography [Figure 2].
The pterygium lesions were revealed as
hyperautofluorescence patterns in the AS-AF
images of 21 (84%) patients. This autofluorescence
area displayed a greater size than the pterygium
size displayed in slit-lamp photography in one
(4%) patient [Figure 3]. On the other hand, four
(16%) patients with pterygium did not demonstrate
an autofluorescence pattern and were reflected
264 JOURNAL OF OPHTHALMIC AND VISION RESEARCH Volume 18, Issue 3, July-Sept 2023
Autofluorescence of Pingueculae and Pterygia; Beheshtnejad et al
completely as hypoautofluorescence pattern in the
AS-AF images [Figure 4].
DISCUSSION
Pinguecula is a common conjunctival disease
and pterygium is another benign conjunctival
disorder that usually grows from the bulbar
conjunctiva and invades the corneal surface.
These degenerative disorders typically affect
the interpalpebral conjunctiva, mostly the nasal
side.[1–4, 11] Sun (ultraviolet light) exposure and
exposure to environmental factors such as
wind and dust increase the risk of these ocular
surface diseases.[12–16] Huseyin Dundar et al
investigated the effects of using soft contact
lenses on pinguecula prevalence.[6]
Recently, AF was introduced as a noninvasive
imaging modality for the diagnosis and follow-up
of several retinal disorders.[9−−10,17−−19] The AF is
obtained by the 488 nm stimulating wavelength
light argon blue laser and with a barrier filter
at 500 nm wavelength, which suppresses the
excitation light. This barrier filter allows the
passage of wavelengths of >500 nm. Short-
wavelength excited signals are mainly derived
from the RPE lipofuscin.[7, 9, 10] It is possible to
capture anterior segment images with the infrared
process of this modality, where AS-AF images are
then registered in fluorescein angiography mode,
without using fluorescein dye.[7–9]
To the best of our knowledge, few studies
have discussed the use of AS-AF imaging
for determining pinguecula or pterygium size.
Moreover, limited studies showed pinguecula
had larger diffuse or punctuate autofluorescence
patterns than the clinical lesions size.[5, 7] Our study
is based on the evaluation of the autofluorescence
size and pattern of pinguecula and pterygium
by AS-AF imaging. It also shows the comparison
of visible conjunctival lesion sizes displayed in
slit-lamp photography.
As the present study showed, in most patients
with pinguecula, the AF pattern was punctate
hyperautofluorescence which showed greater
size than the clinical features as revealed through
slit-lamp photography. On the other hand, in
most patients with pterygium, the AF pattern was
hyperautofluorescence which had a smaller size
than the visible lesion size reflected in slit-lamp
photography. It is noted that the pinguecula lesions
were characterized by hyperautofluorescence
patterns with greater size than the clinical features
of the actual lesion while pterygium lesions were
displayed as hyperautofluorescence patterns with
a smaller size than the clinical features of the
actual lesions. Moreover, the AS-AF imaging of
16% of patients with pterygium did not display
autofluorescence patterns, whereas the AS-AF
imaging of 44% of patients with normal conjunctiva
displayed a small-size hyperautofluorescence
pattern.
Hence, this study shows that although early
inflammatory damages of pinguecula and
pterygium may not be detected in clinical
examinations, AS-AF via autofluorescence
changes can show early signs of inflammatory
damage before clinical presentation.
AF imaging can reveal any changes in
various retinal diseases based on RPE lipofuscin
deposits.[10] These lipofuscin granules contain
specified fluorophores that are responsible
for creating FAF imaging.[5, 7] The lipofuscin
accumulation may be associated with conjunctival
degenerative disorders and some evidence
showed oxidative damage plays an important
role in lipofuscin genesis.[20] Therefore,
the hyper-AF pattern in pinguecula may
originate from lipofuscin granules. However,
in pterygium lesions, the reduction or absence
of autofluorescence reflectivity may depend on
the decreased level of lipofuscin granules or
some fibrovascular blockage. Hence, Further
studies with histopathological and molecular
complimentary evaluations are needed to confirm
this hypothesis.
In summary, normal conjunctiva with healthy
epithelial surface and intact vascular pattern
reveals a hypoautofluorescence pattern in AS-AF
imaging; however, a hyperautofluorescence
pattern may suggest the early stage of a
conjunctival disorder. Therefore, this imaging
modality can be beneficial for detecting the
pathological changes in the early stages of the
conjunctival diseases including pinguecula and
pterygium.
Financial Support and Sponsorship
None.
JOURNAL OF OPHTHALMIC AND VISION RESEARCH Volume 18, Issue 3, July-Sept 2023 265
Autofluorescence of Pingueculae and Pterygia; Beheshtnejad et al
Conflicts of Interest
None.
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