Study of angle of anterior chamber in patients with Type 2 Diabetes
Mellitus
Khanna N.S.1, Anitha J.2
1Dr.
N. Sindhu Khanna, Senior Resident, 2Dr. Anitha J., Assistant Professor, both authors are affiliated
with Department of Ophthalmology, Sapthagiri Institute of Medical
Sciences and Research Center, Bangalore, Karnataka, India.
Corresponding
Author: Dr. Anitha J, Assistant Professor,
Department of Ophthalmology, Sapthagiri Institute of
Medical Sciences and Research Center, Bangalore, Karnataka, India. E-mail: dranithasada@gmail.com
Abstract
Introduction: Open angle Glaucoma is one of the causes of
blindness in diabetic patients. Whether diabetes is a risk factor for angle
closure glaucoma also is less thoroughly studied. Objectives: To assess
the angle of anterior chamber in patients with type 2 diabetes mellitus. Materials and Method: 125 patients (250
eyes) who met the inclusion criteria were taken up for the study. Patients of
both sexes and more than 40 years of age with Type 2 Diabetes Mellitus who do
not come under the exclusion criteria were included. Results: In subjects with duration of diabetes <5 years, Grade 4
angle was found in 47.41% of eyes which was comparatively more than the other
grades. When the duration of Diabetes was 5-10 years, 40% of the eyes had Grade
4 angle and 37.27% had Grade 3 angle. In subjects with >10 years duration of
diabetes, 33.33% had Grade 3 angle. Grade 2 and Grade 4 angles were of equal
distribution with 29.16% and Grade 1 was found to be less. The association of
Grade 1 and Grade 3 angle with severe non-proliferative diabetic retinopathy
was found to be statistically significant. Whereas, in patients with mild
diabetic retinopathy and in moderate non-proliferative diabetic retinopathy
Grade 4 angle is statistically significant.Conclusion:
This study thus concludes the grade of angle of the anterior chamber decreases
as the diabetic retinopathy advances.
Key words: Angle closure glaucoma, Diabetes, Retinopathy
Glaucoma
is one of the causes of blindness and its risk increases in diabetics. Most
previous studies were conducted on Caucasians and have found the association
between diabetes and open angle glaucoma [1,2,3]. Whether diabetes is a risk
factor for angle closure glaucoma also is less clear and less thoroughly
studied. There is some correlation between the width of angle of anterior
chamber and diabetes mellitus which has been recognized in recent times. Any
occludable angle can potentially lead to acute angle closure [4].This study is
done to prove the existing correlation of anterior chamber angle width with
diabetes mellitus, thus helping in an early diagnosis of angle closure and
preventing its complications.
Aims and objectives
To
assess the angle of anterior chamber in patients with type 2 diabetes mellitus.
Materials and Methods
A
hospital based cross sectional clinical study of patients with diabetes
mellitus was conducted in a Tertiary care centre. Informed and written consent
was taken from the patients. 125 patients (250eyes) who met the inclusion
criteria were taken up for the study. Patients of both sexes and more than 40
years of age with Type 2 Diabetes Mellitus who do not come under the exclusion
criteria were included. Patients with history of ocular inflammations, ocular
surgeries, blunt or penetrating ocular trauma were excluded. A detailed
proforma is devised for the collection of data.
After
taking an informed consent, all subjects underwent the following work up:
Detailed
history of patients regarding name, age, sex, occupation, address, drug history,
presenting symptoms, duration, associated conditions and past history was
recorded. Duration of diabetes and type of treatment was enquired.
A
complete ophthalmologic examination was done which includes best corrected visual
acuity, intra-ocular pressure measurement, gonioscopy to view the angle of
anterior chamber, detailed anterior segment examination and dilated fundus
examination.
Perimetry
was planned when the anterior chamber angle had Shaffer Grading 1 (or < 1)
or the optic disc changes suggestive of glaucoma was present. Dilated fundus
examination was done to evaluate the optic disc and to grade the diabetic
retinopathy changes according to ETDRS guidelines.
Analysis
of variance (ANOVA) was used for comparison between the groups for continuous
variables. Post- hoc test (Dunnett’s test) was used for comparing the different
groups with each other, with a confidence interval of 95%. A p-value of less
than 0.05 was considered statistically significant.
Results
A
total of 125 patients (250 eyes) were enrolled in this study. The age group
ranged from 40 to 80 years with a mean of 57.14 ± 9.27, out of which 64 were
males and 61 were females. Among the 250 eyes, 5 eyes had Shaffer Grade 1 angle
of anterior chamber which accounts to 2%.45 eyes had Grade 2 angle accounting
for 18%. Grade 3 angle was found in 93 eyes implying 37.20%. 107 eyes had grade
4 angle which accounts for 42.80%.
Duration
of diabetes has been classified into 3 categories as < 5 years, 5-10 years
and > 10 years (Table 1)
In
subjects with duration of diabetes <5 years, Grade 4 angle was found in
47.41% of eyes which was comparatively more than the other grades (Table 2).
Table-1: Duration of Diabetes
Duration of diabetes |
No. of patients |
Percentage of patients |
Less than 5 years |
58 |
46.40% |
5-10 years |
55 |
44% |
More than 10 years |
12 |
9.60% |
Table-2: Distribution of Grades of angle structures in
eyes with < 5 years of duration of Diabetes Mellitus
Grading of anterior chamber angle |
Percentage |
Grade 1 |
1.72% |
Grade 2 |
12.06% |
Grade 3 |
37.93% |
Grade 4 |
47.41% |
Table-3:Distribution of grades of angle structures in
eyes with Diabetes Mellitus of 5-10 years of duration.
Grading of anterior chamber angle |
Percentage |
Grade 1 |
0.90% |
Grade 2 |
21.81% |
Grade 3 |
37.27% |
Grade 4 |
40% |
When
the duration of Diabetes was 5-10 years, 40% of the eyes had Grade 4 angle and
37.27% had Grade 3 angle (Table 3)
Table-4: Distribution of Grades of angle structures in
eyes with Diabetes Mellitus> 10 years of duration
Grading of anterior chamber angle |
Percentage |
Grade 1 |
8.33% |
Grade 2 |
29.16% |
Grade 3 |
33.33% |
Grade 4 |
29.16% |
In
subjects with >10 years duration of diabetes, 33.33% had Grade 3 angle.
Grade 2 and Grade 4 angles were of equal distribution with 29.16% and Grade 1
was found to be less. However when compared with the other groups Grade 1 was
found to be statically significant (p= 0.045) in patients with more than 10
years duration of diabetes mellitus (Table 4)
Table-5: Angle of anterior chamber with different grades
of retinopathy
Angles of anterior chamber |
Retinopathy grading |
P value |
1 |
Mild NPDR |
0.080 |
Moderate NPDR |
0.684 |
|
Severe NPDR |
0.000 |
|
2 |
Mild NPDR |
0.080 |
Moderate NPDR |
0.088 |
|
Severe NPDR |
0.039 |
|
3 |
Mild NPDR |
0.684 |
Moderate NPDR |
0.088 |
|
Severe NPDR |
0.000 |
|
4 |
Mild NPDR |
0.000 |
Moderate NPDR |
0.039 |
|
Severe NPDR |
0.000 |
On comparing the width of angle of anterior
chamber with severity of diabetic retinopathy, the following were noted.
The
association of Grade 1 and Grade 3 angle with severe non-proliferative diabetic
retinopathy was found to be statistically significant with a p value of 0.000.
Whereas, in patients with mild diabetic retinopathy and in moderate non-proliferative
diabetic retinopathy Grade 4 angle is statistically significant (value of
0.000) (Table 5).
Discussion
Our
study showed that the patients with type II diabetes mellitus had shallow
anterior chamber in relation to the duration of the disease and severity of
diabetic retinopathy. The relation was statistically significant with p value
less than 0.05.
Increasing
lens thickness and decreasing anterior chamber depth with increasing duration
of diabetes have been confirmed in a population based twin study and it was
also found that anterior chamber depth was negatively correlated with duration
of diabetes [5].There have been no Indian studies done on the impact of angle
of anterior chamber with respect to duration of diabetes. Tai MC, Lin SY et al
proved that acute hyperglycemic status did not cause any significant change in
anterior chamber depth, lens thickness [6].
Studies
have found that diabetic patients have a shallower anterior chamber, thicker
central cornea and lens. Tanjong Pagar Survey conducted by Seang Mei Saw and
associates stated that in Singapore Chinese population with diabetes had
shallower anterior chambers and thicker lens than those without diabetes[2].In
a study which involved 150 canine eyes, the anterior chamber depth was
significantly reduced in eyes with diabetic cataracts compared with eyes with
non-cataractous lens [7].
There
is some correlation between the width of angle of anterior chamber and diabetes
mellitus which has been recognized in recent times. Any occludable angle can potentially
lead to acute angle closure [2].Devereux and Foster conducted a cross-
sectional study on 1000 Mongolian patients and concluded that the measurement
of axial anterior chamber depth detects occludable angles in this Asian
population and therefore they have a major role in screening for primary
angle-closure glaucoma [8].
A two phase, cross sectional, community based study was
conducted by Foster, Devereux et alon rural and urban areas of Mongolia where
1717 diabetic subjects were examined. Occludable angles were identified in
140 subjects, 28 of these had PACG.15% were under grade 1 with a
sensitivity and specificity of 84% and 86% respectively for the detection of
occludable angles, thus
proving the significance of occludable angle in diabetics [9].
According
to Browning and Rotberg as the diabetic retinopathy severity progresses, the
anterior chamber depth becomes shallow. It has been proved that certain
treatment for diabetic retinopathy such as scleral buckling can lead to forward
rotation of ciliary body and secondary narrowing of anterior chamber angle.
Silicone oil or pneumatic retinopexy in which the gas is used, can also push
the iris forward and obstruct the aqueous outflow.
In
our study we found out that Grade 1 angle was statistically significant in Severe
NPDR group when compared to other groups. Whereas, Grade 4 angle was
statistically significant in mild retinopathy group.
This
suggests that gonioscopy can be used as a screening tool in all patients with a
longer duration of diabetes mellitus to rule out angle closure, thus preventing
its complication further.
Summary & Conclusion
Diabetes
mellitus is a major health problem throughout the world and there has been a
significant increase in the prevalence of diabetes over the last few years,
particularly in India. It is a highly prevalent group of metabolic diseases
associated with long term damage, dysfunction and failure of various organs
especially the eyes. As majority of all diabetic patients have Type- II
diabetes or adult onset diabetes [10], this study has been directed towards
those patients. Thus the present study was carried out to evaluate the impact
of diabetes mellitus on anterior chamber width in relation to duration of disease
and severity of retinopathy which has been analyzed with a proper statistical
tool.
We
carried out a cross-sectional study in125 patients (250 eyes) who presented to
our hospital who had type II diabetes mellitus.
A
thorough history and complete ophthalmologic examination was done which
includes best corrected visual acuity, intra-ocular pressure measurement,
gonioscopy to view the angle of anterior chamber, detailed anterior segment
examination and dilated fundus examination.
Studies
have shown that diabeticshave shallow anterior chamber and thicker lens than
non diabetics. Diabetic patients who have shallow anterior chambers are prone
for angle closure glaucoma. This study has found significant
statisticalcorrelation between the width of anterior chamber angle and duration
of diabetes mellitus.
There
was also a statistically significant correlationbetween the width of anterior
chamber angle and the severity of diabetic retinopathy.
Since
shallow anterior chamber can be a predisposing factor for developing angle
closure glaucoma, gonioscopy can be used as a screening tool for diabetic
patients particularly in those with a longer duration of the disease and as
severity of retinopathy progresses.
References
How to cite this article?
Khanna N. S, Anitha J. Study of angle of anterior chamber in patients with Type 2 Diabetes Mellitus. Ophthal Rev: Tro J ophtha & Oto.2019;4(1):38-41.doi:10.17511/jooo.2019.i1.08