Multimodal Imaging of Torpedo Maculopathy With Fluorescence Adaptive Optics Imaging of Individual Retinal Pigmented Epithelial Cells

Head stabilization apparatus for high-resolution ophthalmic imaging

Head movement must be stabilized to enable high-quality data collection from optical instrumentation such as eye trackers and ophthalmic imaging devices. Though critically important for imaging, head stabilization is often an afterthought in the design of advanced ophthalmic imaging systems, and experimental devices often adapt used and/or discarded equipment from clinical devices for this purpose. Alternatively, those seeking the most stable solution possible, including many users of adaptive optics ophthalmoscopy systems, utilize bite bars. Bite bars can provide excellent stability but are time consuming to fabricate, decreasing imaging efficiency, and uncomfortable for many patients, especially the elderly and/or those with prosthodontics such as dentures who may refuse participation in a study that requires one. No commercial vendors specifically offer head mount solutions for experimental ophthalmic imaging devices, resulting in nearly every custom device having a different solution for this commonly encountered problem. Parallelizing the head stabilization apparatus across different custom devices may improve standardization of experimental imaging systems for clinical trials and other multicenter investigations. Here we introduce a head mount design for ophthalmic imaging that is modular, adjustable, and customizable to the constraints of different experimental imaging configurations. The three points of head contact in our solution provide excellent stabilization across a range of head sizes and shapes from small children to adults, and the ease of adjustment afforded by our design minimizes the time to get participants stabilized and comfortable.

A rare case of hyperpigmented torpedo maculopathy

PURPOSE

To describe a rare presentation of torpedo maculopathy (TM).

CASE DESCRIPTION

A 25-year-old male was examined in the retina clinic for a macular scar in the left eye. His visual acuity was 20/20, N6 in both eyes and no past history of ocular trauma or any medical or ocular history. The anterior segment was quiet and intraocular pressure was normal.

RESULTS

The patient's left eye on 78D slit lamp biomicroscopy revealed a flat, diffusely hyperpigmented fusiform torpedo-like lesion with sharp margins and surrounding hypopigmentation located predominantly temporal to the fovea, with its tip pointing towards it and just crossing the vertical foveal midline. Dilated fundus examination with binocular indirect ophthalmoscopy revealed no peripheral chorioretinal lesions or vitritis in both eyes. OCT scan through the lesion revealed gross damage to the outer retinal layers, as well as thickening of the retinal pigment epithelium and underlying shadowing, as well as a hyporeflective subretinal cleft involving the lesion. OCT also revealed outer retinal layer damage with an intact retinal pigment epithelium through the lesion's hypopigmented margins. Fundus autofluorescence image revealed a globally hypoautofluorescent lesion in the left eye, with surrounding patchy hyperautofluoroscent areas. Based on the patient history, clinical and imaging findings, other differential diagnoses such as atypical congenital hypertrophy of retinal pigment epithelium (RPE), choroidal nevus, RPE hamartoma, trauma and inflammatory conditions were ruled out. The diagnosis of TM was confirmed based on the typical lesion shape and location.

CONCLUSION

A torpedo lesion with diffuse hyperpigmentation is an unusually rare presentation.

Multimodal Imaging of Choroidal Structural in Torpedo Maculopathy

Objective

To report a case of torpedo maculopathy with multimodal fundus imaging methods, and apply the choroid vascularity index to quantitatively describe the choroidal structural changes in torpedo maculopathy.

Case presentation

An asymptomatic 41-year-old Chinese woman with an incidentally found yellowish-white macular lesion in her left eye was referred to our hospital. She was unaware of any prior medical conditions. The best corrected visual acuity (BCVA) was 20/20 OD and 20/25 OS, respectively. Fundus exam of her left eye revealed a well-circumscribed torpedo-like hypopigmented lesion in the macula region, and the tapered edge directed toward the fovea. Pigment deposition could be seen in the inferotemporal portion of the torpedo lesion. Fluorescein angiography showed the corresponding window defect without leakage and fundus autofluorescence demonstrated low signal throughout the lesion. Enhanced depth imaging optical coherence tomography revealed outer retinal attenuation, subretinal cavitation, subtle inner choroidal excavation and thinning of outer nuclear layer. The diagnosis of torpedo maculopathy was clinically made. Choroidal vascularity index (CVI) and sub-foveal choroidal thickness (SFCT) were applied to display changes of choroidal structure. The results implied that both subfoveal CVI and SFCT of the affected eye seemed relatively lower when compared with the fellow eye. Optical coherence tomography angiography showed reduced density of the choriocapillaris in the temporal area of the lesion and increased capillary density in the nasal area. Functional examinations, including microperimetry, multifocal electroretinogram and static perimetry also revealed reduced retinal sensitivity, decreased stimulated amplitude and suspected scotoma in the lesion area. After 12 months of follow-up, the patient's visual acuity and the clinical appearance of the lesion were unchanged.

Conclusion

The torpedo maculopathy may be identified by abnormal appearance with multimodal imaging. Decreased choroidal vascularity in the lesion area measured quantitatively by choroid vascularity index may play a role in pathogenesis of torpedo maculopathy.

Twenty-five years of clinical applications using adaptive optics ophthalmoscopy [Invited]

Twenty-five years ago, adaptive optics (AO) was combined with fundus photography, thereby initiating a new era in the field of ophthalmic imaging. Since that time, clinical applications of AO ophthalmoscopy to investigate visual system structure and function in both health and disease abound. To date, AO ophthalmoscopy has enabled visualization of most cell types in the retina, offered insight into retinal and systemic disease pathogenesis, and been integrated into clinical trials. This article reviews clinical applications of AO ophthalmoscopy and addresses remaining challenges for AO ophthalmoscopy to become fully integrated into standard ophthalmic care.

Real-time correction of image rotation with adaptive optics scanning light ophthalmoscopy

Fixational eye motion includes typical translation and torsion. In the registration of images from adaptive optics scanning light ophthalmoscopy (AOSLO), image rotation due to eye torsion and/or head rotation is often ignored because (a) the amount of rotation is trivial compared to translation within a short duration of imaging or recording time and (b) computational cost increases substantially when the registration algorithm involves simultaneous detection of rotation and translation. However, it becomes critically important under cases such as long exposure, functional measurements, and precise motion tracking. We developed a fast method to detect and correct rotation from AOSLO images, together with the detection of strip-level motion translation. The computational cost for rotation detection and correction alone is about 5 ms/frame (512×512 pixels) on an nVidia GTX960M GPU. Image quality is compared with and without rotation correction from 10 healthy human subjects and 8 diseased eyes with a total of 180 videos. The results show that residual image motions between the reference images and the registered images with rotation correction are a fraction of those without rotation correction, and the ratio is 0.74-0.89 at the image center and 0.37-0.51 at the four corners of the images.