Transcript
Page 1: Ability of non-ophthalmologist doctors to detect eyes with occludable angles using the flashlight test

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

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Int Ophthalmol (2014) 34:557–561

DOI 10.1007/s10792-013-9856-x

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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

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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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