ORIGINAL PAPER
Ability of non-ophthalmologist doctors to detect eyeswith occludable angles using the flashlight test
Carolina Pelegrini Barbosa Gracitelli • Bruno Landgren •
Flavia Bracale Graciani • Aline Katia Siqueira Sousa •
Augusto Paranhos Jr. • Tiago Santos Prata
Received: 29 March 2013 / Accepted: 14 September 2013 / Published online: 1 October 2013
� Springer Science+Business Media Dordrecht 2013
Abstract The aim of this study is to assess the ability
of non-ophthalmologist doctors to detect eyes with
occludable angles using the flashlight test (FLT). For
this study, a total of 45 patients were prospectively
enrolled. After an ophthalmological examination all
patients underwent FLT by two non-ophthalmologist
examiners in a masked and standardized fashion. Two
gynecologists were chosen, as they often deal with
patients exposed to drugs that can trigger pupillary
block. An occludable angle was defined as C2
quadrants in which the posterior trabecular meshwork
was not visible by gonioscopy without indentation
(performed by an experienced glaucoma specialist).
Whenever both eyes were eligible, one was randomly
selected for analysis. Sensitivity and specificity for
detection of occludable angles were generated, and the
agreement between examiners was assessed. This
study results showed that the mean age was
47.1 ± 16.4 years and most patients were female
(67.7 %). There was a good agreement between
observers for FLT results (j = 0.77; p = 0.04).
Similar values of sensitivity and specificity were
found for both examiners (92 and 67 % vs 97 and
67 %, respectively). Based on the findings of this
study, it was concluded that FLT showed good
sensitivity for detection of eyes with occludable
angles. The fact that it can be easily and reliably
performed by non-ophthalmologist highlights its use
as a screening tool in patients requiring medications
that can induce angle closure.
Keywords Anterior chamber depth �Occludable angle � Screening method �Anticholinergic drugs
Introduction
Recent estimates show that more than 67 million
people in the world have glaucoma. Although open-
angle glaucoma comprises approximately two-thirds
of these cases, angle-closure glaucoma is responsible
for half of those who are blind from the disease [1, 2].
In addition, in populations such as Chinese, Indian and
Mongolian, its prevalence is equal or even greater than
that of open-angle glaucoma [1, 3–7].
Primary angle-closure glaucoma (PACG) results
from a combination of predisposing anterior segment
anatomy and unfavorable physiological behavior [2].
Currently, it is defined as an occludable angle
C. P. B. Gracitelli (&) � B. Landgren �A. K. S. Sousa � A. Paranhos Jr. � T. S. Prata
Ophthalmology Department, Federal University of Sao
Paulo, Rua Botucatu, 821 Vila Clementino,
04023-062 Sao Paulo, Brazil
e-mail: [email protected]
F. B. Graciani
Gynecology Department, Federal University of Sao Paulo,
Sao Paulo, Brazil
123
Int Ophthalmol (2014) 34:557–561
DOI 10.1007/s10792-013-9856-x
associated with trabecular meshwork damage/dys-
function (typically raised intraocular pressure [IOP] or
presence of peripheral anterior synechiae) and struc-
tural and/or functional evidence of glaucomatous optic
neuropathy [8]. Although less common than the
chronic form, the subacute and acute forms of angle
closure may be the first manifestation of the disease.
Reported anatomical risk factors for PACG include
short axial length, shallow anterior chamber (AC),
thick and relatively anterior-positioned lens, and small
corneal diameter and steep curvature [9–12]. Although
an occludable angle can be promptly identified by
indentation gonioscopy, the examination is technically
difficult for non-glaucoma specialists and is not
appropriate for large-scale screening [13, 14].
Different types of systemic medications may trigger
an acute attack in eyes with predisposing anterior
segment anatomy [15–17]. On daily practice, non-
ophthalmologist doctors, such as gynecologists, usually
prescribe these drugs without a preventive AC angle
assessment. This situation highlights the importance of
investigating a straightforward screening method to aid
clinicians in identifying individuals at risk [18].
The flashlight test (FLT) is a simple light-based
method which has been previously described for AC
depth evaluation [19]. This technique has been used in
population-based studies and was found to be a good
screening tool [20–22]. In this study, we aimed to
investigate the ability of non-ophthalmologist doctors
to identify eyes at risk (those with occludable angles
based on gonioscopic examination) using the FLT.
Materials and methods
This cross-sectional study adhered to the tenets of the
Declaration of Helsinki and was approved by the
Institutional Review Board of the Federal University
of Sao Paulo. In addition, written informed consent
was obtained from all participants.
Patients
We prospectively enrolled patients with glaucoma and
glaucoma suspects, attending our outpatient clinic. All
patients underwent a complete ophthalmological
examination. Key exclusion criteria were conditions
precluding clear visualization of the AC (e.g., ptery-
gium, corneal opacity), congenital anterior segment
abnormalities, eyelid alterations, ocular trauma and
intraocular surgery (incisional or laser procedures).
After inclusion, each patient underwent the FLT,
performed by two different gynecologists, in separate
rooms. The eye to be examined was randomly chosen
on the toss of a coin. The test was performed using a
Maglite Cell 2D torch. A flashlight beam was directed
parallel to the iris from the temporal side as originally
reported by Vargas et al. [19]. Eyes identified as
having a narrow AC were those in which a nasal iris
shadow, formed between the limbus and the pupillary
edge, was visualized. Conversely, eyes identified as
having a deep chamber were those in which a nasal
light reflex, formed between the limbus and the
pupillary edge, was visualized. Immediately after the
FLT, patients underwent gonioscopic examination
(Sussmann four-mirror lens) by a glaucoma specialist
(TSP) in a masked fashion. Gonioscopy was per-
formed in a dark room using a Zeiss SL130 slit-lamp
with the minimum intensity of illumination compat-
ible with good visualization. The slit-beam was
shortened so that it did not fall on the pupil. Angles
were graded as occludable (posterior trabecular
meshwork not visible in C2 quadrants without inden-
tation) or nonoccludable.
Statistical analysis
Descriptive analysis was used to present demographic
and clinical data. Agreement between the two non-
ophthalmologist examiners (gynecologists) and the
glaucoma specialist was determined using the
weighted Kappa (j) statistic. A j value of 0–0.2
suggests poor agreement, 0.2–0.6 fair, 0.6–0.8 sub-
stantial, 0.8–1.0 represents almost perfect agreement,
and[0.75 is usually considered good agreement [23].
Values of sensitivity and specificity were also gener-
ated, considering the gonioscopic grading of the angle
as the gold standard.
Results
A total of 45 patients were included. The mean age of
study patients was 47.1 ± 16.4 years (range
19–85 years) and the majority of patients were female
(67.7 %). The percentage of eyes identified as having
a narrow AC by the FLT was 20 % for the first
observer and 18 % for the second observer (n = 9 and
558 Int Ophthalmol (2014) 34:557–561
123
8, respectively). The prevalence of occludable angles
according to gonioscopy was 20 % (n = 9).
The j value was 0.77 (p = 0.04), showing good
agreement between the two gynecologists. Similar
values of sensitivity and specificity were found for the
two examiners (92 and 67 % vs 97 and 67 %,
respectively (Table 1). Regarding the cases in which
there was no agreement between gonioscopy and FLT
grading, three eyes with occludable angles were
classified as having deep ACs while three eyes with
nonoccludable angles were classified as having narrow
ACs by the first observer. For the second observer, two
eyes with occludable angles were classified as having
deep ACs while one eye with a nonoccludable angle
was classified as having a narrow AC.
Examples of eyes with occludable and nonocclud-
able angles, correctly identified by the FLT, are given
in Figs. 1 and 2, respectively.
Discussion
Patients are often treated by non-ophthalmologist
doctors with systemic medications that can trigger an
acute angle-closure attack in anatomically predis-
posed eyes [19, 24]. Although a glaucoma specialist
can identify those at risk before such medications are
prescribed, this type of specific evaluation is not
always available, and probably not feasible in daily
practice. Gonioscopy itself requires specific training
and cannot be performed by a general clinician [19,
24]. These facts emphasize the need for a reliable and
sensitive screening method. In the present study, we
demonstrated the FLT as a useful tool for identifica-
tion of eyes at risk (with occludable angles) by non-
ophthalmologist doctors.
There is scant information in the literature about the
use of the FLT as a screening method. In most of the
available studies, although non-trained clinicians were
not evaluated as examiners, good sensitivity values
were found [19, 21, 25]. In our study, investigating the
applicability of the test when performed by two
gynecologists, FLT also had good sensitivity (92 %
for the first observer and 97 % for the second
observer), which is in agreement with previously
published data [21, 22]. In contrast with the majority
of publications, one study from the south of India
reported very low sensitivity (45 %) using the same
technique [26]. One possible reason for the differences
of reported sensitivity values between studies could be
the variability of anterior segment anatomy in some
populations that could influence the type of angle-
closure mechanism, affecting the efficacy of the FLT
[24]. Van Herick et al. [27] pointed out that the
flashlight method might be subject to misclassification
in eyes with either plateau iris configuration or with
central shallowing of the AC but wide drainage angles.
Table 1 Sensitivity and specificity values for the flashlight
test (two examiners)
Observer 1 (%) Observer 2 (%)
Sensitivity 92 97
Specificity 67 67
Considering the gonioscopic grading of the angle as the gold
standard
Fig. 1 Eye with a nonoccludable angle correctly identified by
the flashlight test
Fig. 2 Eye with an occludable angle correctly identified by the
flashlight test
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The main clinical implication of our findings is that
the FLT could be used by general doctors to identify
patients at risk for angle closure before prescribing
some medications. In any medical field, an ideal
screening test should have high sensitivity. Although it
would possibly lead to a significant number of false
positive test results, the majority of the patients at risk
could be detected and referenced to a more specific
ophthalmological evaluation [25]. The fact that we
found sensitivity values[90 %, independently of the
observer, confirms the FLT as a relevant screening
tool.
In the context of our study, it is important to discuss
the most common medications that could trigger an
acute glaucoma attack. They include topical mydria-
tics, anticholinergic drugs, adrenergic agents, drugs
for upper respiratory infections, antidepressants, anti-
convulsants, sulfamate derivative, antihistamines and
cabergoline [28]. These drugs when prescribed for a
patient with an anatomically predisposed eye may
result in high intraocular pressure, reduction in visual
acuity, glaucomatous optic neuropathy, visual field
loss and blindness [29, 30].
Looking carefully at the characteristics of patients
that develop an acute glaucoma attack, one should be
careful with elderly women when prescribing any of
the above cited medications. There is a predominance
of female patients with pupillary block, which is
probably caused by a shallower AC observed in these
eyes [31–34]. In our sample, the majority of patients
were female (67.7 %). Another risk factor is age. The
prevalence of papillary block and PACG also
increases with age. The depth and volume of the AC
diminish, which may result from a thickening and
forward displacement of the lens [35]. In this study the
mean age of patients was 47.1 ± 16.4 years, which is
not considered an elderly population.
Some specific characteristics of our study should be
considered. First, our study is limited by its small
sample size and low prevalence of narrow angles,
which probably reflects the prevalence of narrow
angles in Brazil. Second, some studies have compared
FLT with Van Herick test as a screening test [26]. We
have chosen not to make a comparison with Van
Herick’s method because our focus was to investigate
non-ophthalmologist doctors as observers.
In summary, the FLT showed good sensitivity to
detect eyes with occludable angles. The fact that
it can be easily and reliably performed by non-
ophthalmologist doctors highlights its use as a
screening tool in patients requiring medications that
can induce angle closure.
Conflict of interest The authors have no conflict of interest
regarding the present study.
Funding None.
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