Case 1
The first case was about a 40 years old man with focal laser treated CSC in his right eye (RE). Best corrected visual acuity (BCVA) at the presentation was 0.4 (decimal fraction), which has improved to 0.8 in one year and 1.0 in two years. Before treatment the patient presented:
- Ophthalmoscopy: a round serous macular detachment with small yellow sub-retinal deposits;
- OCT: neurosensory detachment, elongation of the photoreceptors outer segment and hyperreflective dots in the subretinal fluid (SRF);
- FA: point leak within the macula in early phase, that gradual increased in intensity and size in midphase;
- FAF: the edges of neurosensory detachment slightly hypoautofluorescent (hypo-AF), hyperautofluorescent (hyper-AF) dots and three hypo-AF lesions;
After comparing the FA with FAF images, it was observed that the leakage point overlapped with a hypo-AF lesion (Fig. 1).
The SRF disappeared in about two months. In this paper, we compared AO and FAF images taken one and two years after the treatment. On the AO images the most important black (hyporeflective) and white (hyperreflective) lesions were noted. No differences were observed between one and two-years-old OCT.
One year after the focal LASER photocoagulation:
- FAF: the edges of neurosensory detachment still visible but less hypo-AF; less hyper-AF dots and five hypo-AF lesions (including the photocoagulation point);
- AO cone mosaic: blurred cone mosaic in the fovea, with intensely white and black lesions ; normal and blurred mosaic in the parafoveal area.
Two years after the focal LASER photocoagulation:
- FAF: the edges of neurosensory detachment less hypo-AF, less hyper-AF dots and four hypo-AF lesions;
- AO cone mosaic: normal and blurred mosaic alternate, with less intensely white and black lesions in the fovea.
Almost all hyper-AF lesions appeared white on AO cone mosaic and the hypo-AF ones appeared black[8]. Within a year, most black lesions on the cone mosaic decreased in size and white lesions decreased in intensity (Fig. 2). In the end, these changes were associated with an improvement in visual acuity.
Case 2
A 22 years old female, presented with the diagnosis of RP. The main symptoms were nyctalopia and loss of peripheral vision for about a year. BCVA was RE=1.0 and left eye (LE)= 0.7. The funduscopic examination revealed typical clinical changes for RP: bone-spicule pigmentary changes, arteriolar attenuation and waxy disc pallor. OCT showed a normal retinal thickness in the center of the macula, atrophy of the outer retinal layers (ORL) from the perifoveal area to the periphery in both eyes [9]. On the OCT it was observed that the ellipsoid zone (EZ) and the interdigitation zone (IZ) were differently impacted [10][11]. . Depending on the integrity of the ORL, three areas were observed:
Area I- consisting of external limiting membrane (ELM), EZ, IZ and RPE;
Area II- consisting of ELM, EZ and RPE;
Area III- consisting of ELM and RPE.
On the FAF images, the characteristic hyper-AF ring has been observed in both eyes. Correlating these results, we observed that the hyper-AF ring corresponded in particular to Area II of the ORL integrity (Fig. 3).
The AO high-resolution images were compatible with FAF and OCT images[12]. Three types of cone mosaic phenotypes were observed:
-Normal cone mosaic: well-defined photoreceptor cells, located in the center of the fovea;
-Blurred cone mosaic ring: in the parafoveal area, surrounding the normal cone mosaic; a rapid deterioration of the cone mosaic from the inner to the outer edge of the ring was observed;
-Cone disappearance: lack of cone mosaic outside the blurred ring, with visible RPE.
Photoreceptor density was measured in four different points from the center to the periphery. A dramatic decrease in cone density was observed and it was impossible to determine the density at the blurred ring area. The highest cone density was 21.863cones/mm2 in the RE and 24.240 cones/mm2 in the LE, both measured at 1º temporal to the center (Fig. 4).
Case 3
A 43 years old patient, male, diagnosed with STGD, was sent to our clinic for a second opinion. The main symptoms were binocular decrease in visual acuity, especially in the right eye, for several years, abnormalities of color vision and dark adaptation. BCVA at the presentation was RE=0.2 and LE=1.0. Posterior pole examination revealed: central macular atrophy that spared the fovea in the LE, “beaten bronze” appearance and yellow-white fundus flecks.
The OCT showed atrophy of the central retina in both eyes and pointed out the intact fovea in the LE. FAF exam showed typical abnormalities for STGD: hyper-AF of the fundus flecks, hypo-AF of the atrophied areas with increased autofluorescence around them and sparing of the peripapillary area (Fig. 5). However a small difference was observed between the FAF of the two eyes: in the RE the central hypo-AF area is surrounded by more tissue with increased autofluorescence as opposed to the left eye.
On the AO high-resolution images several types of lesions could be observed. These are some of the cone mosaic phenotypes we have noticed:
- atrophic areas: lack of cone mosaic with visible RPE;
- periatrophic areas with increased FAF: blurred cone mosaic and less visible photoreceptors, with some areas of starry-night cone pattern;
- periatrophic areas with normal FAF: normal cone mosaic.
Due to the lack of fixation in the right eye, the images obtained with AO have several artifacts. In both eyes the fundus flecks appeared intensely hyperreflective, with a granular appearance, with few areas at which the cones could be observed (Fig. 6).
Related to the cone density, as expected, in the RE it was lower in the center than in the parafoveal area. In the LE, due to the alternation of the intact areas with the affected ones, the cone density varied. However even in the LE it was much higher in the parafoveal region than in the fovea. The highest density of cones was 12.594cones/mm2 in the RE and 16.297cones/mm2 in the LE.
Case 4
This was the case of a 17 years old patient, female, who had a central scotoma in both eyes for about a year. BCVA was 1.0 in both eyes. Nothing pathological was observed on the slit lamp biomicroscopy examination of the anterior pole. The funduscopic examination revealed the presence of yellow dot-like deposits in the fovea of both eyes (Fig. 7).
OCT showed the interruption of the EZ and IZ in the fovea in both eyes. FAF identified normal metabolic activity in both eyes, without autofluorescence anomalies. Taking into account clinical, paraclinical data and patient history, the diagnosis of light-induced retinopathy was made.
Due to the high resolution of the images, AO was able to highlight in the most detailed way the anatomical changes in this case. In both eyes the mosaic of cones was altered in the center of the fovea, with RPE visible in certain areas and with a blurred area around them (Fig. 8). The quantitative analysis showed a low cone density in the center of the fovea and at the level of the blurred cone mosaic. The density of photoreceptors increased towards the periphery reaching normal limits in the perifoveolar areas. In the RE the cone density was 10.804cones/mm2 at 0.1 º to the center and 25.571cones/mm2 at 1.12 º to the center (in the LE the results were almost the same).