Confocal scanner gives ophthalmologists valuable new tool
We had the opportunity to test the new autofluorescence function of confocal retinal imager in our Center of Medical Retina at the Ophthalmologic Clinic of Hospital Sacco (Milan University).
Autofluorescence is a diagnostic exam that, today, should be used routinely for more accurate diagnosis and easier differential diagnosis. Blue-light autofluorescence is of special importance because it highlights the macular pigment, hence playing a crucial role in diagnosis of macular alterations. Blue-light FAF, however, requires confocal scanners.
One of the advantages of the imaging device is the possibility to obtain, in automatic mode, FAF images of a field of 60° even in case of poor dilatation of the pupil. We report below the case of an eight-year-old patient, where the capability to capture a field of 60° showed its importance in the diagnosis.
The images (Figure 1) show bilateral alterations of the retina, consisting in hyperfluorescent areas known as ‘flecks’, a typical lesion of Stargardt disease.
The above-mentioned lesions can extend beyond the retinal arcades; it is therefore very important to capture an image that includes the mid periphery of the retina; this to observe all lesions of the fundus in the same frame. Despite the non-collaborative behaviour of the patient (due to the young age) and a severe photosensitivity, it was possible to capture high-quality images of the retina.
The FAF examination is also of importance in patients affected by lamellar hole, as shown in Figure 2.
The lesion, clearly visible in autofluorescence, involves mainly the foveal zone, with a retinal delamination, generally between the outer plexiform layer and the outer nuclear layer. The autofluorescence is also of importance to define the differential diagnosis and the adequate treatment in case of pseudo-hole, as such patients do not have loss of retinal tissue.
Finally, one of the most frequent cases where the autofluorescence exam demonstrates its importance is probably in geographic atrophy (Figure 3).
To evaluate the retinal damage in this disease, it is better to rely on autofluorescence imaging rather than on visual acuity. As a matter of fact, autofluorescence proved to be more accurate than true colour photos in the evaluation of the lesions’ borders. Geographic atrophy can be the outcome of different pathologies, evolving into similar retinal lesions.
Today it is paramount to identify and differentiate the patterns of posterior pole atrophy. There are many clinical trials aimed at the evaluation of efficacy and safety of new pharmacologic treatments; the availability of high-quality documentation of the lesions has direct consequences on the therapy of the patients. A continued follow up of patients by means of autofluorescence images is of great help in following their evolution and the progression of the pathologies.