Perle Tumahai

Reliability of cone counts using an adaptive optics retinal camera

To assess the reproducibility and repeatability of cone imaging in healthy human eyes, using the RTx‐1 Adaptive Optics Retinal Camera and its proprietary cone‐counting software.

Quantification of cone loss after surgery for retinal detachment involving the macula using adaptive optics

Aims To image the cones in eyes with anatomically successful repair of retinal detachment (RD) involving the macula and in healthy fellow eyes using an adaptive optics (AO) camera and to correlate the results to clinical outcomes. Methods Twenty-one patients (42 eyes) operated for macula-off RD were imaged 6 weeks after surgery using an AO camera (RTX 1, Imagine Eyes, Orsay, France). Cone density (cells/mm2), spacing between cells (µm) and the percentage of cones with six neighbours were measured. Best-corrected visual acuity (BCVA) and thickness of the inner segment ellipsoid (ISe) band imaged by SD-optical coherence tomography were also measured. Results The parafoveal cone density was decreased in eyes operated for RD (mean±SD 14 576±4035/mm2) compared with fellow eyes (20 589±2350/mm2) (p=0.0001). There was also an increase in cone spacing (10.3±2.6 vs 8.0±1.0.9 µm, respectively, p<0.0001). The nearest-neighbour analysis revealed a reduction in the percentage of cones with six neighbours (36.5±4.2 vs 42.7±4.6%, p=0.0003). The ISe thickness, thinner in the operated eyes, was correlated to the cone density (r=0.62, p<0.0001). BCVA was significantly correlated to cone density (r=0.8, p<0.001). Conclusions There was a decrease in the cone density after RD with an estimated loss of one-third of the cones. Postoperative visual acuity was highly correlated with the cone density. AO may be a valuable prognostic tool after RD surgery.

Reflectivity of the Outer Retina on Spectral-Domain Optical Coherence Tomography as a Predictor of Photoreceptor Cone Density

PURPOSE To investigate the relationship between outer retinal reflectivity on spectral-domain optical coherence tomography and cone density in the corresponding area. DESIGN Prospective cross-sectional observational study. METHODS In this institutional-based study, 20 eyes of 10 patients presenting maculopathies with various degrees of impairment of the photoreceptor layer (central serous chorioretinopathy, chronic central serous chorioretinopathy, maculopathy associated with hydroxychloroquine, and healthy eyes) were studied. Selection criteria were intended to ensure good image quality. Inner segment ellipsoid band reflectivity, global retinal reflectivity, and relative inner segment ellipsoid reflectivity (defined as the ratio of inner segment ellipsoid band reflectivity on overall retinal reflectivity) were measured on a longitudinal reflectance profile extracted from the spectral-domain optical coherence tomography B-scan. The cone metrics were measured in the same region of interest, located in the perifoveal area, using an adaptive optics retinal camera. RESULTS Inner segment ellipsoid and relative ellipsoid reflectivity were closely correlated with cone density (Pearson r: 0.72 and 0.70, respectively, P < .01). CONCLUSION Outer retinal reflectivity on the transversal optical coherence tomography scan can be correlated to adaptive optics in terms of photoreceptor density. This quantitative approach using optical coherence tomography images could have important implications in the management of maculopathies.

Assessment of parafoveal cone density in patients taking hydroxychloroquine in the absence of clinically documented retinal toxicity.

To measure cone density in patients taking hydroxychloroquine (HCQ), with no clinical evidence of maculopathy.

Vitreous Microparticle Shedding in Retinal Detachment: A Prospective Comparative Study.

PURPOSE Microparticles (MPs) are membrane-derived vesicles measuring less than 1 μm in diameter. They are shed from nearly every activated or preapoptotic cell and may exhibit biologic activities in inflammation or apoptosis settings. The main purpose of this study was to determine whether MP shedding was higher in the vitreous of patients with retinal detachment (RD). METHODS This was a prospective, comparative study. Levels of vitreous MPs (including phosphatidylserine [PS]-expressing MPs, photoreceptor cell-derived MPs, and photoreceptor cell-derived MPs expressing PS) and soluble proinflammatory factors (i.e., monocyte chemoattractant protein-1, intercellular adhesion molecule-1, and IL-6) were analyzed by flow cytometry. Samples were obtained from 49 eyes undergoing RD surgery and 41 control eyes. RESULTS Vitreous levels of all the MPs studied were significantly increased in the RD group. Vitreous MP levels were correlated with levels of at least one proinflammatory factor depending on MP subsets. Concerning clinical parameters, vitreous PS-expressing MP and PS-expressing photoreceptor cell-derived MP levels were higher depending on the duration of RD at surgery, the detached retina surface, and the macula status and were found more sensitive than proinflammatory factors only for the duration of RD at surgery. CONCLUSIONS Vitreous concentrations of MPs (mainly derived from photoreceptor cells) are higher after rhegmatogenous RD and found to be correlated with soluble proinflammatory factors.