Diabetic Retinopathy & Medical Retina - aioseducation

70th AIOC Proceedings, Cochin 2012
The most obvious advantage of truly simultaneous imaging is the negation of
the possibility that one of the angiogram is of the higher quality as compared
to the other, which may lead to differences in visualization of the pathological
states. The other significant advantage of the simultaneous angiography
technique is the time sequence correlation. Both the dyes are injected and,
therefore, imaged simultaneously. Therefore, the physiological differences
in their distribution and circulation through the eye are easily discernible.
Furthermore, the differences in response to the pathological states of the
retinal and choroidal circulation are made obvious and are readily comparable.
Thus, the relative value of each type of dye in normal physiology and different
disease processes becomes apparent, which is relevant for both clinical and
research purposes.
Lastly the time required to perform the entire study is considerably shorter.
Patient compliance and investigator‘s ease are noteworthy.
HRA has an added advantage of simultaneously carrying out the OCT with
FA or ICG. It gives additional information of the pathology. The ability to scan
images at 40 kHz help reduce eye movement artifacts and increases patient
comfort, providing cleaner images. TruTrack image alignment technology
provides eye tracking and guiding of the SD-OCT. This feature aligns
images in the same examination and finds the same location in subsequent
examinations to track subtle changes over time.
Fluorescein angiography has always been a gold standard investigation in
cases of CSC. It reveals two main types of leaks inkblot pattern and smokestack
type. No definite leak was seen in 19% 21 of cases in a study than 12% in our
study. The literature reports 22,23,24,25,26,27,28 the incidence of smokestack leak to be
7 to 25% and that of inkblot leak 60 to 87%. Spitnaz and Huke 26 observed that
the leaks are most often found in the superonasal quadrant (33.22%). In our
study we also found superonasal quadrant to be the commonest site (33.33%).
The usual number of leakages are one or two in various studies 22,25,26 that too
in our study.
Occassionally, in spite of presence of clinically appreciable CSC no leak is
found in FA. Gass 29 had suggested the following possibilities for such a
situation – 1) The leaking point has healed; 2) A leak has occurred outside the
macular area; 3) In presence of the peripheral retinal hole or a choroidaltumor;
4) Associated with congenital pit of the ONH.; 5) In idiopathic uveal effusion
syndrome. CSC without leak may be due to healing of the leaking point or
points and delay in the absorption of the subretinal fluid.
The development of OCT has provided a better understanding of the
mechanism in CSC, especially the abnormalities in the RPE layer. We
visualized clearly a minute defect of the RPE within the PED, which seemed
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