Transcript 2011 Direct Measurement of the Ciliary Sulcus Diameter by

In the name of GOD
Direct Measurement of the Ciliary Sulcus
Diameter by Ultrasound
Biomicroscopy and Correlation with
White to White measurement.
Seyed Javad Hashemian MD
Eye Research Center
Rasoul Akram Hospital
Tehran University of Medical Sciences
No financial interest
[email protected]
WWW.Drhashemian.com
Tehran-IRAN
ASCRS, San Diego, March /27/ 2011
lens sizes & Correspondence between white-to-white and sulcus
diameter
Published studies have not found any anatomical correspondence between white-towhite and sulcus diameter, suggesting that some lens sizing issues may be explained
by the assumption that sulcus diameter can be estimated from white-to-white.
Posterior chamber phakic IOLs using a sizing criteria of adding 0.50 mm to the
white-to-white in eyes where the anterior chamber depth (ACD) was 2.80 to 3.50
mm, and adding 1.00 mm to the white-to-white in eyes where the ACD was >3.50
mm.
The common theme regarding postoperative complications of posterior chamber
phakic IOL surgery is that of lens sizing
An oversized lens can cause angle closure leading to malignant glaucoma, or the
lens can chafe the iris leading to pigment dispersion
An undersized lens can cause cataract or damage to the zonules with dislocation of
the phakic IOL
Recently, a 35-MHz UBM was developed, and this device seems to be more
accurate than other methods because it can measure ciliary sulcus diameter from 1
image, even though the image resolution is not as good as that of 50-MHz UBM.
In the present study, we measured ciliary sulcus diameters using a 35-MHz UBM
and evaluated the correlation with white-to-white distances.
PURPOSES :
To evaluate the correlation of white to white measurement between Caliper and
Orbscan and relation to sulcus to sulcus dimension measured by UBM.
In this cross-sectional observational study we measured sulcus to sulcus
dimension of 203 eyes of high myopic patients who presented to be assessed for
phakic IOL surgery. we measured sulcus to sulcus dimension by UBM and
horizontal white-to-white distance using Orbscan IIz and Caliper.
Mean W-W dimension , differences between methods of measurement and
correlation with S- to- S diameter was evaluated .
METHODS:
Horizontal white-to-white distances were measured by scanning slit topography
using Orbscan IIz (Bausch & Lomb)
UBM ciliary sulcus measurement
Topical tetracaine 0.5% was instilled to anesthetize the cornea before measurement.
One of 3 differently sized eyecups (18 mm, 20 mm, and 22 mm) was inserted
depending on the ocular aperture size. An eyecup was filled with sterile normal
saline and the subject was asked to fixate on a ceiling target with the fellow eye to
maintain accommodation and fixation.
Diameters of the ciliary sulcus were measured using a VuMax-II UBM equipped
with a 35-MHz transducer. Cross-sectional images were obtained on the horizontal
RESULTS:
Mean W-W dimension in Caliper group was 11.63 mm ±0.38 mm (
range 10.8-12.5mm),
By Orbscan was 11.80mm ± 0.42 mm (range 10.5mm-13.2mm) .
Mean S-S dimension by UBM was 12.14mm ± 0.43mm ( range
11.07-13.37mm)
Mean difference of S-S and W-W by Caliper was 0.49mm±0.26mm (
range -0.18-1.65mm)
Mean difference of W-W by Orbscan – Caliper was 0.10mm
±0.25mm ( range -0.30-2.20mm).
Correlation:
The correlation of white to white diameter measured by Caliper and
Orbscan with sulcus to sulcus dimension measured by UBM was
78.4% and 71%respectively.
Instrument
Mean
SD
Minimum
Maximum
UBM Sulcus to Sulcus
12.14
0.432
11.07
13.37
UBM Angle to Angle
11.31
0.534
10.09
12.88
Orbscan IIz (WTW)
11.80
0.429
10.5
13.2
Caliper (WTW)
11.63
0.380
10.8
12.5
Mean
SD
UBM Ciliary Sulcus Diameter (mm)
12.14
0.432
Caliper White to white Diameter (mm)
11.64
0.357
Mean
SD
UBM Ciliary Sulcus Diameter (mm)
12.15
0.432
Orbscan Iiz White to white Diameter (mm)
11.80
0.429
Mean
SD
11.65
0.380
11.75
0.462
Caliper White to white Diameter (mm)
Orbscan Iiz White to white Diameter (mm)
Correlation
Coefficient
P Value
0.784
0.000
Correlation
Coefficient
P Value
0.701
0.000
Correlation
Coefficient
P Value
0.891
0.000
CONCLUSIONS:
The 35-MHz UBM is an accurate method for direct
measurement of the ciliary sulcus diameter for
proper determination of posterior chamber phakic
IOL size
The White-to-white measurements by Caliper and
Orbscan are an acceptable method to predict the
ciliary sulcus diameter in myopic patients if UBM is
not available.