Ophthalmic nurse practitioner led diabetic retinopathy screening. Results of a 3-month trial

Abstract

To describe the design and implementation of a nurse led diabetic retinopathy screening clinic. To present the results of a 3-month trial period assessing the concordance of retinopathy grading between a nurse practitioner and an ophthalmologist.
Patients attending for annual diabetic eye review during an initial 3-month trial period were assessed in a dedicated diabetic eye clinic by an ophthalmic nurse practitioner and an ophthalmologist, with both grading the degree of diabetic retinopathy using to the Wisconsin grading system. Each was masked as to the other's findings. The concordance of retinopathy grading between ophthalmic nurse practitioner and ophthalmologist was assessed.
A total of 95 patients (189 eyes) were assessed during the study period. A 92% concordance was achieved between the ophthalmologist and the ophthalmic nurse practitioner. In total, 72 eyes were graded as having some degree of retinopathy by the ophthalmologist. The sensitivity of the nurse practitioner for diagnosing the presence of diabetic retinopathy was 93%, and the specificity 91%. Nine eyes with severe nonproliferative diabetic retinopathy or worse, and four with clinically significant macular oedema were seen. All were correctly identified by the nurse practitioner.
The structure and management protocols of the clinic are described. An excellent concordance between ophthalmologist and nurse practitioner was achieved in this group of patients with relatively less advanced retinopathy.

Full text

Ophthalmic nurse
practitioner led
diabetic retinopathy
screening. Results of
a 3-month trial
BJ Kirkwood, DJ Coster, RW Essex
Abstract
Purpose To describe the design and
implementation of a nurse led diabetic
retinopathy screening clinic. To present the
results of a 3-month trial period assessing
the concordance of retinopathy grading
between a nurse practitioner and an
ophthalmologist.
Method Patients attending for annual
diabetic eye review during an initial 3-month
trial period were assessed in a dedicated
diabetic eye clinic by an ophthalmic nurse
practitioner and an ophthalmologist, with
both grading the degree of diabetic
retinopathy using to the Wisconsin grading
system. Each was masked as to the other’s
findings. The concordance of retinopathy
grading between ophthalmic nurse
practitioner and ophthalmologist was
assessed.
Results A total of 95 patients (189 eyes) were
assessed during the study period. A 92%
concordance was achieved between the
ophthalmologist and the ophthalmic nurse
practitioner. In total, 72 eyes were graded as
having some degree of retinopathy by the
ophthalmologist. The sensitivity of the nurse
practitioner for diagnosing the presence of
diabetic retinopathy was 93%, and the
specificity 91%. Nine eyes with severe
nonproliferative diabetic retinopathy or
worse, and four with clinically significant
macular oedema were seen. All were
correctly identified by the nurse practitioner.
Conclusions The structure and management
protocols of the clinic are described. An
excellent concordance between
ophthalmologist and nurse practitioner
was achieved in this group of patients
with relatively less advanced
retinopathy.
Eye (2006) 20, 173–177. doi:10.1038/sj.eye.6701834;
published online 28 October 2005
Keywords: diabetic retinopathy; nurse
practitioner; Wisconsin grading system;
screening; public health
Introduction
The prevalence of diabetes mellitus is
increasing, with 2.9% of the population known
to be affected in Australia in 2001.
1
There is a
similar prevalence in the UK, and it is possibly
higher in the USA.
2,3
The disease is more
prevalent among selected racial groups,
4,5
and a
significant proportion of the diabetic population
remains undiagnosed.
2,3
This large and
increasing number of diabetics directly impacts
on the workload of ophthalmologists as all
require regular eye review. Clinical
classification of diabetic retinopathy is well
described, making it suited to assessment by
a trained observer.
6
Ophthalmic nurse
practitioners and other health care providers
may be increasingly utilised in the screening of
diabetic patients. Quality assurance is an
essential requirement of any such screening
program. The present study describes the
design of an ophthalmic nurse practitioner led
diabetic retinopathy screening clinic including
provision for ongoing quality assurance, and
presents the results of an initial 3-month
evaluation period involving assessment of all
patients by both an ophthalmologist and an
ophthalmic nurse practitioner.
Materials and methods
Clinic structure and protocols
A management protocol for a nurse led diabetic
retinopathy screening clinic was established in
Received: 8 September
2004
Accepted in revised form:
12 December 2004
Published online: 28
October 2005
Data previously presented at
the Australian Ophthalmic
Nurse’s Association 23rd
Annual Conference. Sydney,
Australia. June 2004. None
of the authors has any
financial interest in the
contents of the manuscript
Flinders Medical Centre,
Adelaide, Australia
Correspondence:
BJ Kirkwood, Department
of Ophthalmology,
Flinders Medical Centre,
Bedford Park SA 5042,
Australia
Tel: þ 8 8204 4252;
Fax: þ 8 8404 2040.
E-mail: brad_kirkwood70@
hotmail.com
Eye (2006) 20, 173–177
& 2006 Nature Publishing Group All rights reserved 0950-222X/06 $30.00
www.nature.com/eye
CLINICAL STUDY

conjunction with the retinal service at Flinders Medical
Centre (Figure 1). Patients who had already been seen in
an eye clinic previously, and who were due for annual
diabetic eye review were eligible for review in the nurse-
led clinic, which was held weekly. Exclusion criteria were
age less than 18 years, any previous retinal laser
photocoagulation and known ocular comorbidity. When
patients attended the clinic, a full ophthalmic history was
taken. Visual acuity and intraocular pressure were
measured and the pupils were examined. The anterior
segment was examined with the aid of the slit-lamp for
signs of pathology, particularly iris rubeosis, then the
pupils were dilated with 1% tropicamide. Dilated fundal
examination was next performed using the slit lamp
biomicroscope and a 78 diopter lens. Patients were
examined in nine directions of gaze. The presence and
severity of any diabetic retinopathy was recorded using
the simplified Wisconsin grading, and any diabetic
maculopathy was specifically noted.
7,8
For all patients,
the importance of blood sugar control and regular
follow-up was emphasised. The results of the assessment
determined subsequent patient management. In all cases,
follow-up was determined by the more severely affected
eye. Patients with no diabetic retinopathy were booked in
for review in the nurse led clinic in 2 years. Patients with
minimal or mild nonproliferative diabetic retinopathy
(NPDR) were booked in for review in the nurse led clinic
in 1 year. Patients with moderate NPDR were booked in
for review in the nurse led clinic in 6 months. All patients
with severe NPDR, or any signs of proliferative diabetic
retinopathy (PDR), as well as any suspicion of macular
oedema (whether clinically significant or not) were
promptly referred back to an ophthalmologist led clinic
within 2 weeks for further assessment and management.
These thresholds for referral were set to allow a margin
of safety between the need for referral and need for
therapeutic intervention. Patients were also referred back
into an ophthalmologist run clinic if any of the following
were present: inability to assess diabetic retinopathy for
any reason, visual acuity less than 6/12 corrected in
either eye, intraocular pressure greater than 21 in either
eye, or other significant ocular comorbidity. Standards
were set for correspondence with other health
professionals, and protocols were established for patients
who failed to attend appointments. The nurse
practitioner was free to exercise judgement and to review
patients sooner (but not later), or to refer any other
patients to the ophthalmologist clinic.
Patient Management Flow chart In The Nurse Led Clinic
No DR
Minimal
NPDR
Mild
NPDR
Moderate
NPDR
Severe
NPDR
PDR
Rubeosis
iridis
Maculopathy
Clinically
Significant
Macular
Oedema
2 year
review
12 month
review
6 month
review
Refer to
medical staff
Refer to
medical staff
VA 6/12 and
Outcome
Refer:
Inadequate view of fundus
IOP> 21 mm Hg
Visual Acuity < 6/12
Other ocular pathology
Full history
Visual Acuity
Slit Lamp Examination
IOP
Pupil examination
Dilate (Tropicamide 1% OU)
Dilated ocular & fundal examination
≥
±
Figure 1 Diagrammatic representation of patient management in the ophthalmic nurse practitioner led clinic. DR ¼ diabetic
retinopathy; NPDR ¼ nonproliferative diabetic retinopathy; PDR ¼ proliferative diabetic retinopathy.
Nurse led diabetic retinopathy screening
BJ Kirkwood et al
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Eye

Study design
Having established this model for the clinic, its
introduction was planned in two phases. The first phase
involved a 3-month trial period, which was initiated to
evaluate the safety aspects of an ophthalmic nurse
practitioner led clinic. This trial period is the subject of
the present paper. During this period all patients were
seen by the ophthalmic nurse practitioner (BK) and a
consultant ophthalmologist from the retinal service (RE).
Each clinician assessed the degree of retinopathy in each
eye, and graded it in a masked fashion. These results
were recorded prospectively, and later collated and
analysed. During this first phase it became evident that
there were very few patients with anything worse than
mild diabetic retinopathy, and also very few with
maculopathy. It was decided that the ophthalmic nurse
practitioner would also attend the ophthalmologist run
clinic and assess a number of patients with sight-
threatening retinopathy, again in a masked fashion.
These eyes are included in the results presented.
If a good degree of correlation was achieved, the clinic
was to be continued under the leadership of the
ophthalmic nurse practitioner (Phase 2). At least 80%
concordance between ophthalmologist and ophthalmic
nurse practitioner in Phase 1 was prospectively decided
as necessary to allow this to happen. In this second
phase, ongoing quality assurance and education is
planned. For any patient referred out of the nurse led
clinic for ophthalmic assessment, the findings of the
nurse practitioner and the ophthalmologist will be
recorded and correlated in an ongoing manner, with
periodic review by the department of ophthalmology.
The nurse led clinic is run concurrently with the retinal
clinic, and most consultant referrals are performed on the
same day. Any such same day referrals are used as an
opportunity for ongoing clinician education.
Results
In total, 95 five patients (189 eyes) were examined during
the initial 3-month study period (Table 1). One patient
had a blind eye with an opaque cornea as the result of a
previous penetrating eye injury and no view of the retina
was possible on that side. Of these patients, 82 were seen
in the nurse led clinic, and 13 in the consultant clinic at a
time when the nurse practitioner was present. There was
an exact concordance in 173 eyes (91.5%), while 12 (6.3%)
were within one grade of diabetic retinopathy and four
(2.1%) were within two grades of diabetic retinopathy.
The sensitivity of the ophthalmic nurse practitioner for
diagnosing any diabetic retinopathy was 93% (67/72),
and the specificity was 91% (67/74). Macular oedema
was assessed independently to other changes of
retinopathy. Four eyes (2.1%) were assessed as having
clinically significant macular oedema (CSME) by the
ophthalmologist. All were identified by the nurse
practitioner. One additional eye was assessed as having
CSME by the nurse practitioner. The sensitivity of the
ophthalmic nurse practitioner in detecting CSME was
therefore 100%, and the specificity was 80%. Very few
eyes with sight-threatening retinopathy were seen in the
nurse led clinic. Of the four eyes with CSME and the nine
eyes with severe NPDR or worse, all but one eye with
CSME and two eyes (one patient) with severe NPDR
were seen primarily in the consultant clinic at a time
when the nurse practitioner was also attending for
educational purposes. All those with severe NPDR or
PDR were correctly identified by the nurse practitioner.
A total of 82 patients were seen in the nurse led clinic.
In total, 19 (23%) were referred out due to comorbidity,
two were referred on due to severity of diabetic
retinopathy, and 61 (74%) were booked for review in the
nurse led clinic.
Table 1 Results of diabetic retinopathy grading by ophthal-
mologist and ophthalmic nurse practitioner
Results of assessment
by ophthalmologist
Result of assessment by nurse
practitioner of corresponding
patients
Degree of
retinopathy
n Degree of
retinopathy
n
No DR 117 No DR 110
Minimal NPDR 3
Mild NPDR 4
Minimal NPDR 26 Minimal NPDR 20
No DR 5
Mild NPDR 1
Mild NPDR 24 Mild NPDR 23
Minimal NPDR 1
Moderate NPDR 13 Moderate NPDR 11
Mild NPDR 2
Severe NPDR 6 Severe NPDR 6
Low-risk PDR 1 Low-risk PDR 1
High-risk PDR 1 High-risk PDR 1
Advanced PDR 1 Advanced PDR 1
Any DR 72 Any DR 67
No DR 5
No CSME 185 No CSME 184
CSME 1
CSME 4 CSME 4
DR ¼ diabetic retinopathy; NPDR ¼ nonproliferative diabetic retinopathy;
PDR ¼ proliferative diabetic retinopathy; CSME ¼ clinically significant
macular oedema.
Nurse led diabetic retinopathy screening
BJ Kirkwood et al
175
Eye

As a result of the high concordance of diabetic
retinopathy assessment between ophthalmologist and
ophthalmic nurse practitioner, the clinic has been
continued as planned (‘Phase 2’).
Discussion
An ophthalmic nurse practitioner is a nurse who has
received additional training and experience in the
management of patients with ophthalmic disease. In
Australia this training must be recognised by the state
nursing authorities and the place of employment before
the title ophthalmic nurse practitioner can be used.
A nurse practitioner has the right to refer patients to
other health care providers, order investigations, and
administer a range of medications.
A very high concordance between the findings of the
ophthalmologist and ophthalmic nurse practitioner was
achieved in the current study. This was in a group of
patients who had previously been assessed by an
ophthalmologist, and had been booked in for annual
review due to their relatively less advanced retinopathy.
Nearly two-thirds of all patients were assessed by the
ophthalmologist as having no diabetic retinopathy at all.
This relative paucity of retinopathy would have
increased the degree of concordance between
ophthalmologist and nurse. The concordance was still
very good (63/72, 88%) in eyes judged to have some
degree of retinopathy by the ophthalmologist.
There was complete concordance between
ophthalmologist and ophthalmic nurse practitioner for
eyes with severe NPDR or any PDR. In addition, there
was complete concordance for eyes judged to have CSME
by the ophthalmologist. The number of eyes with this
degree of sight-threatening retinopathy was however
very small, and it is not possible to accurately assess the
diagnostic sensitivity of the ophthalmic nurse
practitioner for such eyes.
The clinic structure was such that patients with any
sight-threatening retinopathy were promptly referred
back to an ophthalmologist. The threshold for referral
was deliberately set lower than the accepted thresholds
for intervention to give the clinic a margin for diagnostic
error. Sight-threatening retinopathy was very rare in the
nurse led clinic. This also lent a degree of safety to the
clinic design. There is however the risk that a clinician
working solely in such a clinic may lose familiarity with
the appearance of more severe retinopathy. It is planned
therefore that the second phase of clinic implementation
be modified to include ongoing periodic attendance of
the nurse practitioner in the consultant clinic.
The present standard of care for diabetic retinopathy
screening is dilated fundal examination by an
ophthalmologist, preferably with an interest in retinal
disease, and using indirect slit-lamp biomicroscopy. The
‘gold standard’ used in several larger trials of diabetic
retinopathy is seven field stereo photography, which is
highly reproducible and sensitive.
6,9–11
The correlation
between ophthalmologist assessment and seven field
photography was 86% in one study, although 26% of
proliferative diabetic retinopathy was missed.
12
For eyes
with microaneurysms only, ophthalmoscopy may miss as
many as 50% of cases.
13
The present study has not
endeavoured to compare a nurse practitioner with the
gold standard but rather to the present standard of care.
The concordance between ophthalmologists and other
health professionals has been investigated in other
studies. Concordances of between 48 and 77% have been
reported for optometrists detecting any retinopathy.
14–16
In a large series by Prasad et al
17
using a simplified retinal
grading system, only 1.16% of patients with sight-
threatening retinopathy were missed by optometrists.
Nonconsultant physicians were found to be ‘correct’ in
their assessment in 30% of cases, improving to 67% with
training in one study.
18
General practitioners have been
reported to detect diabetic retinopathy in 65% of cases,
and to correctly diagnose and refer sight-threatening
retinopathy in 37%.
14,19
It is difficult to compare these
results directly with those of the present study due to
differences in the retinopathy grading systems used. The
system used in the present study was more sensitive to
small differences in severity of retinopathy, and if
anything would tend to have decreased the interobserver
concordance. Despite this, the concordance achieved was
excellent.
Screening for diabetic retinopathy using photographic
techniques is also used. The sensitivity for detecting
diabetic retinopathy is good using mydriatic cameras,
20
however the results with nonmydriatic cameras are more
variable.
21
Patient satisfaction is likely to be better when
diabetic retinopathy screening is performed by a clinician
rather than photographically. Compliance with
established screening recommendations is perhaps the
biggest barrier to minimisation of diabetes related
blindness.
22,23
Photo-screening at the point of primary
care (eg the local doctor or the pharmacist) has the
potential to significantly improve compliance. The design
of the nurse led clinic in the current study is unlikely to
significantly improve compliance with screening, except
that it makes more screening appointments available.
The design of the present study was such that the
financial implications of nurse led diabetic retinopathy
screening were not assessed. It is probable that it is less
expensive than an ophthalmologist led primary screening
program. It is likely to be cost competitive with photo-
screening, since the staff cost is similar and there is not
the need for an expensive retinal photographic system,
nor the associated cost of reading the photographs. In the
Nurse led diabetic retinopathy screening
BJ Kirkwood et al
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Eye

present model there is no additional visit required when
significant retinopathy is detected, as the ophthalmologist
clinic is run concurrently and patients can be ‘walked
round’ for further assessment and treatment on the same
day. This could equally be the case for photo-screening,
although not if provided at the point of primary care.
A very high concordance was achieved between the
grading of diabetic retinopathy by an ophthalmic nurse
practitioner and by an ophthalmologist. This has
validated the safety of independent diabetic retinopathy
screening by an ophthalmic nurse practitioner, and
allowed an ongoing assessment clinic to be established.
The design of the clinic is described in detail to allow
other groups to use this model, with quality assurance
and education integral to the ongoing clinic.
Acknowledgements
We would like to thank Dr Russell Phillips, Consultant
Ophthalmologist, for his contributions to the Discussion
section of this paper.
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