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appearance; multifocal ERGs or FMERGs are
useful in determining the site of the pathology.
Acknowledgements
This study was supported by the Suzuken Memorial
Foundation.
Naoki Terauchi, Kaoru Fujinami, Kei Shinoda,
Kazushige Tsunoda, Gen Hanazono,
Yozo Miyake
Laboratory of Visual Physiology, National Institute of
Sensory Organs, National Hospital Organization,
Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro-
ku, Tokyo 152-8902, Japan
Koichi Inomata
Department of Ophthalmology, School of Medicine,
Nihon University, 1-8-13 Surugadai, Kanda, Chiyoda-ku,
Tokyo 101-8309, Japan
Correspondence to: Dr Kei Shinoda, Laboratory of
Visual Physiology, National Institute of Sensory Organs,
National Hospital Organization, Tokyo Medical Center,
2-5-1 Higashigaoka, Meguro-ku, Tokyo 152-8902,
Japan; shinodakei@kankakuki.go.jp
doi: 10.1136/bjo.2006.113373
References
1 Rizzo III JF. Neuroophthalmologic disease of the
retina. In: Daniel MA, ed. Principles and practice of
ophthalmology, 2nd ed. Philadelphia: WB
Saunders, 2000:4083–108.
2 MiyakeY,ShiroyamaN,HoriguchiM,etal.Oscillatory
potentials in electroretinograms of the human macular
region. Invest Ophthalmol Vis Sci 1988;29:1631–5.
3 Miyake Y. Focal macular ERGs. In: Miyake Y, ed.
Electrodiagnosis of retinal diseases. Tokyo:
Springer, 2005:20–32.
4 Ueno S, Kondo M, Niwa Y, et al. Luminance
dependence of neural components that underlies the
primate photopic electroretinogram. Invest
Ophthalmol Vis Sci 2004;45:1033–40.
5 Sieving PA, Murayama K, Naarendorp F. Push-pull
model of the primate photopic electroretinogram: a
role for hyperpolarizing neurons in shaping the b-
wave. Vis Neurosci 1994;11:519–32.
In-vivo scanning of Ascher
intrastromal corneal ring opacity
Case report
An 80-year-old man was seen with abnormal
corneal appearances. He was asymptomatic with
no previous ocular, medical or drug history.
Visual acuities were 6/6 in both eyes unaided;
with ocular examination revealing bilateral
0.1 mm wide white intrastromal corneal ring
opacities 7.8 mm and 7.7 mm in diameter in the
right and left eyes, respectively (fig 1). Corneal
sensation was normal with no evidence of
thinning, scarring or vascularisation. The
remaining ocular examination was normal.
Blood tests for lipid, protein and autoimmune
markers were normal. Corneal pachymetry and
topography was unremarkable. Cross-sectional
imaging of the cornea with anterior segment
optical coherence tomography (Visante OCT,
Carl Zeiss Meditec, Inc., USA) revealed opacifi-
cation affecting the entire thickness of the
stroma (fig 2). Confocal microscopy (HRT II/
Rostock Cornea Module; Heidelberg
Engineering GmbH, Germany) of the ring
opacity revealed microdot extracellular deposits
within the corneal stroma (fig 3). The epithe-
lium and endothelium of the cornea appeared
normal. Ocular examination of the patient’s
sister was unremarkable, with another sister
unavailable for examination. There has been no
progression with over 12 months follow-up with
the patient remaining asymptomatic.
Comment
Originally reported by Ascher
1
in 1963, intracor-
neal rings are rare;
2–8
occurring both unilaterally
Figure 2 Focal macular electroretinogram (FMERG, top), full field electroretinogram and visual
evoked response (VEP) from both eyes (bottom). Top: Upper three recordings show the photopic a- and
b-waves, and lowest recordings show the oscillatory potentials (Ops). The stimulus spot size was 5
˚
,
10
˚
and 15
˚
as indicated in the figure. Left and centre: FMERGs recorded during the acute phase. The
ERGs of the left eye (centre) are reduced compared with those of the right eye. Right: FMERGs recorded
on the following day showing the recovery of all components of the left eye. The a-wave is not affected
as much as the b-waves and Ops. Bottom left: Bright-flash ERG showed no significant difference in the
two eyes even in the oscillatory potentials which are sensitive to retinal ischaemia. Bottom right: The
VEPs showed no significant difference between the two eyes. The stimulus onset of full field ERG and
VEP is indicated by arrows.
Accepted 3 February 2007
Competing interests: None of the authors have any
financial or proprietary interest in any material or
methods mentioned.
The supplemental figure is
available at http://bjo.bmj.
com/supplemental.
Figure 1 Right eye: intrastromal corneal ring
0.1 mm in width, 7.8 mm in vertical diameter.
Figure 2 Optical coherence tomography of left
cornea: highly reflective deposits are seen
throughout the entire thickness of the corneal
stroma.
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or bilaterally, varying in both ring width and
diameter in patients 25–80 years of age.
Haematological and autoimmune investigations
have been normal and family members have not
been affected. Pachymetry and specular micro-
scopy have been unremarkable.
34
Bopp and
Laqua
5
described minute greyish dots distributed
within outer stromal layers forming an arcus
lipoides-like circular band on biomicroscopy. In
contrast, Melles et al.
6
could not detect corneal
deposition on biomicroscopy but commented on
acoustic reflectivity similar to corneal tissue.
We performed optical coherence tomogra-
phy, which demonstrated the full thickness
involvement of the corneal stroma. Confocal
microscopy of the ring opacity revealed the
presence of highly reflective extracellular opa-
cities located within the affected stroma.
Hypotheses for their aetiology include an
unknown corneal dystrophy or degeneration.
6
Bron
2
suggested that the rings represent an
immunological reaction, with stromal damage
at the site of previous antigen–antibody inter-
actions, although their discreteness and stabi-
lity would argue against this. The appearance
of the rings, particularly on confocal micro-
scopy, would suggest that they represent
anomalous exogenous or endogenous extra-
cellular microdeposits in the corneal stroma.
Their apparent stability, discrete positioning in
the midperipheral cornea and lack of any
associated infiltrative or inflammatory
response is possibly suggestive of altered
collagen fibril formation.
D Q Nguyen, S A Quah, N Kumar, A Jacob,
S B Kaye
St Paul’s Eye Unit, Department of Ophthalmology, Royal
Liverpool University Hospital, Liverpool, UK
Correspondence to: Dan Nguyen, Department of
Ophthalmology, Royal United Hospital Bath, Combe
Park, Bath BA1 3NG, UK; danqbnguyen@hotmail.com
References
1 Ascher KW. [An unusual corneal ring.] (In
German). Ber Zusammenkunft Dtsch Ophthalmol
Ges 1963;65:44–6.
2 Bron AJ. Peripheral ring opacity of the cornea.
Br J Ophthalmol 1969;53:270–3.
3 Khan JC, Shuttleworth GN. Annular granular corneal
opacity: a rare corneal stromal dystrophy or
degeneration? Br J Ophthalmol 2000;84:1205–6.
4 Silvestri A, Boisjoly H. Bilateral corneal ring opacity
of unknown origin. Cornea 2003;22:86–7.
5 Bopp S, Laqua H. [Corneal Ascher ring. A
ring-shaped stromal corneal opacity.]
Figure 3 Confocal microscopy of left cornea
(depth 352 mm): microdeposits are visible as
sparkling corpuscles spread within the
extracellular tissue of the stroma. Collagen is seen
located in the centre of the image with
surrounding keratocytes.
Informed consent was obtaired for publication of fig 1.
doi: 10.1136/bjo.2006.109322
Accepted 12 February 2007
Financial interests: None.
Competing interests: None declared.
Figure 1 (A) Retinal vein diameters (arbitrary units) in the temporal inferior vessel arcade and the
temporal superior vessel arcade and as mean of all measurements in 24 patients with retinal vein
occlusions without treatment during follow-up. (B) Retinal vein diameters (arbitrary units) in the
temporal inferior vessel arcade and the temporal superior vessel arcade and as mean of all
measurements in 21 patients with retinal vein occlusions receiving an intravitreal injection of
approximately 20 mg triamcinolone acetonide.
PostScript 1711
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(In German). Klin Monatsbl Augenheilkd
1991;198:201–4.
6 Melles GR, de Sera JP, Eggink CA, et al. Bilateral,
anterior stromal ring opacity of the cornea.
Br J Ophthalmol 1998;82:522–5.
7 Laqua H. [Paracentral ring-like corneal opacity.] (In
German). Ber Zusammenkunft Dtsch Ophthalmol
Ges 1972;71:583–5.
8 Rieger G. [Primary unilateral annular opacity of the
cornea.] (In German). Fortschr Ophthalmol
1987;84:242–4.
Decreased retinal vein diameter
after intravitreal triamcinolone for
retinal vein occlusions
Recent studies have suggested that macular
oedema caused by central retinal vein occlu-
sion may be treated by intravitreal triamcino-
lone acetonide.
1–5
In these investigations,
macular oedema and retinal thickening mark-
edly decreased and visual acuity temporarily
increased after the intravitreal application of
triamcinolone acetonide. The purpose of the
present study was to evaluate whether the
diameters of the retinal veins change after the
intravitreal injection of triamcinolone aceto-
nide. It may give hints for alterations in the
retinal haemodynamics after the intravitreal
application of triamcinolone acetonide.
Care report
The comparative non-randomized clinical
interventional investigation included a study
group of 21 patients (21 eyes) with central
retinal vein occlusion (n = 9) or branch
retinal vein occlusion (n = 12) who received
an intravitreal injection of approximately
20 mg triamcinolone acetonide as described
recently.
3
Mean age was 69.3 ¡ 8.6 years,
mean refractive error was 0.36 ¡ 1.12 diop-
ters, and mean follow-up was
8.9 ¡ 5.9 months (range 2.1–22.2 months). A
control group consisting of 24 patients (24
eyes) with central retinal vein occlusion
(n = 9) or branch retinal vein occlusion
(n = 15) did not receive any treatment.
Mean age was 61.8 ¡ 14.3 years, mean refrac-
tive error was 0.32 ¡ 1.81 diopters, and mean
follow-up was 7.6 ¡ 5.8 months (range 2.0–
23.3 months). On fluorescein angiograms
obtained at baseline and during the follow-
up, the diameters of the affected veins were
measured at the inferotemporal and super-
otemporal optic disc border, above and below
the fovea, and between the optic disc and the
infrafoveal location or the suprafoveal location.
The measurements were obtained in relative
size units.
At baseline, the study group and control
group did not vary significantly in age
(p = 0.09), gender (p = 0.56), refractive error
(p = 0.34), and follow-up (p = 0.43), nor in the
diameter measurements of the retinal veins
(p.0.30). In the study group and in the control
group, retinal vein diameters decreased sig-
nificantly during follow-up (table 1; fig1). The
amount of decrease in the retinal vein dia-
meters did not vary significantly between the
study groups (p.0.15; table 1). Visual acuity
increased significantly from 0.95 ¡ 0.60 loga-
rithm of the minimum angle of resolution
(logMAR) to 0.78 ¡ 0.69 logMAR (p = 0.006;
95% confidence intervals (CI) 20.28, 20.05) in
the study group, and did not change signifi-
cantly in the control group (0.51 ¡ 0.36
logMAR versus 0.44 ¡ 0.35 logMAR;
p = 0.17; 95% CI 20.17, 0.03). In the study
group, the change in retinal vein diameter was
statistically not associated with a change in
visual acuity (p.0.15) (fig 2).
Comment
The results suggest that in patients with retinal
vein occlusions, a triamcinolone-associated
increase in visual acuity is statistically inde-
pendent of a concurrent decrease in retinal
vein diameter. In agreement with other stu-
dies, it may be an indication that the anti-
oedematous effect of intravitreal triamcinolone
occurs at other vascular levels, such as the
capillary bed, than at the level of the large
retinal veins. As the decrease in retinal vein
diameters did not vary significantly between
the treatment group and the control group, one
may infer that intravitreal triamcinolone may
not have a marked effect on retinal vein
dilatations, and indirectly, on the retinal vein
outflow resistance, in eyes with retinal vein
occlusions.
Table 1 Diameters of retinal veins in relative size units (mean ¡ SD) at baseline of the study and during follow-up in 45 patients
with retinal vein occlusions who either received an intravitreal injection of triamcinolone acetonide (study group) or who did not
receive any treatment (control group)
Baseline Follow-up p Value 95% CI
Study group
n21
Temporal inferior vessel arcade 0.125 ¡ 0.032 0.111 ¡ 0.027 0.031 20.023, 20.001
Temporal superior vessel arcade 0.135 ¡ 0.029 0.114 ¡ 0.025 0.002 20.030, 20.008
Total 0.130 ¡ 0.025 0.113 ¡ 0.022 0.001 20.024, 20.007
Control group 24
Temporal inferior vessel arcade 0.127 ¡ 0.035 0.104 ¡ 0.021 ,0.001 20.032, 20.010
Temporal superior vessel arcade 0.126 ¡ 0.034 0.100 ¡ 0.027 ,0.001 20.037, 20.015
Total 0.126 ¡ 0.029 0.102 ¡ 0.021 ,0.001 20.033, 20.015
CI, Confidence interval.
p Value, Statistical significance of difference between baseline values and measurements obtained during follow-up.
Figure 2 Scattergram showing the change in retinal vein diameter related to the change in visual
acuity during follow-up in 21 patients with retinal vein occlusions receiving an intravitreal injection of
approximately 20 mg triamcinolone acetonide; the relationship was statistically not significant
(p = 0.18).
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