Purpose To assess between- and within-individual variability of macular cone topography in the eyes of young adults. Design Observational case series. Methods Cone photoreceptors in 40 eyes of 20 subjects aged 19–29 years with normal maculae were imaged using a research adaptive optics scanning laser ophthalmoscope. Refractive errors ranged from −3.0 D to 0.63 D and differed by <0.50 D in fellow eyes. Cone density was assessed on a two-dimensional sampling grid over the central 2.4 mm × 2.4 mm. Between-individual variability was evaluated by coefficient of variation (CV). Within-individual variability was quantified by maximum difference and root-mean-square (RMS). Cones were cumulated over increasing eccentricity. Results Peak densities of foveal cones are 168,162 ± 23,529 cones/mm2 (mean ± SD) (CV = 0.14). The number of cones within the cone-dominated foveola (0.8–0.9 mm diameter) is 38,311 ± 2,319 (CV = 0.06). The RMS cone density difference between fellow eyes is 6.78%, and the maximum difference is 23.6%. Mixed model statistical analysis found no difference in the association between eccentricity and cone density in the superior/nasal (p=0.8503), superior/temporal (p=0.1551), inferior/nasal (p=0.8609), and inferior/temporal (p=0.6662) quadrants of fellow eyes. Conclusions New instrumentation imaged the smallest foveal cones, thus allowing accurate assignment of foveal centers and assessment of variability in macular cone density in a large sample of eyes. Though cone densities vary significantly in the fovea, the total number of foveolar cones are very similar both between- and within-subjects. Thus, the total number of foveolar cones may be an important measure of cone degeneration and loss.

High-resolution retinal images in CHM carriers and affected males demonstrated RPE and photoreceptor cell degeneration. As both RPE and photoreceptor cells were affected, these cell types may degenerate simultaneously in CHM. These findings provide insight into the effect of CHM mutations on macular retinal structure, with implications for the development of treatments for CHM. (ClinicalTrials.gov number, NCT00254605.).

The human retina is a uniquely accessible tissue. Tools like scanning laser ophthalmoscopy (SLO) and spectral domain optical coherence tomography (SD-OCT) provide clinicians with remarkably clear pictures of the living retina. While the anterior optics of the eye permit such non-invasive visualization of the retina and associated pathology, these same optics induce significant aberrations that in most cases obviate cellular-resolution imaging. Adaptive optics (AO) imaging systems use active optical elements to compensate for aberrations in the optical path between the object and the camera. Applied to the human eye, AO allows direct visualization of individual rod and cone photoreceptor cells, RPE cells, and white blood cells. AO imaging has changed the way vision scientists and ophthalmologists see the retina, helping to clarify our understanding of retinal structure, function, and the etiology of various retinal pathologies. Here we review some of the advances made possible with AO imaging of the human retina, and discuss applications and future prospects for clinical imaging.

Objective Assess outer retinal layer maturation during late gestation and early postnatal life using optical coherence tomography (OCT) and histology. Methods Thirty-nine subjects ranging from 32 weeks post-menstrual age (PMA) to 4 years were imaged using a hand held OCT (102 imaging sessions). Foveal images from 16 subjects (21 imaging sessions) were normal and evaluated for inner retinal excavation and presence of outer retinal reflective bands. Reflectivity profiles of central, parafoveal, and perifoveal retina were extracted and compared to age-matched histological sections. Results Foveal pit morphology in infants was generally distinguishable from adults. Reflectivity profiles showed a single hyper-reflective band at the fovea in all infants less than 42 weeks PMA. Multiple bands were distinguishable in the outer retina at the perifovea by 32 weeks PMA, and at the fovea by 3 months post term. By 17 months postnatal the characteristic appearance of four hyper-reflective bands was evident across the foveal region. These features are consistent with previous results from histology. A ‘temporal divot’ was present in some infants and foveal pit morphology and extent of inner retinal excavation was variable. Conclusions Hand-held OCT imaging is a viable technique for evaluating neonatal retinas. In premature infants, who do not develop ROP, the foveal region appears to follow a developmental time course similar to in utero maturation. Clinical Relevance As pediatric OCT imaging becomes more common, a better understanding of normal foveal and macular development is needed. Longitudinal imaging offers the opportunity to track postnatal foveal development in preterm infants where poor visual outcomes are anticipated or to track treatment outcomes in this population.

Objective To evaluate subclinical macular findings in premature patients at risk of retinopathy of prematurity (ROP) with the use of handheld spectral domain-optical coherence tomography (SD-OCT). Design Prospective, observational case series. Participants Forty-nine prematurely born neonates. Methods Forty-nine infants were imaged using a handheld SD-OCT. Images were acquired in non-sedated infants in the neonatal intensive care unit. Some patients were followed and re-imaged over the course of several weeks. Two hundred ninety-eight total images were acquired, and evaluated for cystoid macular edema (CME) and persistence of inner retinal layers. Main Outcome Measures In vivo determination of foveal retinal lamination, image analysis and clinical observation. Results Two hundred forty (81%) of the images from 45 patients were usable (defined as having scans passing through the fovea with clearly identifiable retinal layers). Persistence of one or more inner retinal layers was seen in 42 patients (93%). Patients with at least one persistent layer, 16, 5, 7, 13 and 1 had a maximum ROP stage of 0, 1, 2, 3, and 4A respectively. CME was seen in 25 of the 45 patients (56%) during one or more imaging sessions. CME was present in 9, 1, 5, 9, and 1 patient with maximum ROP stage of 0, 1, 2, 3, and 4A respectively. Conclusions Our data suggests there is persistence of inner retinal layers in premature infants, regardless of maximal ROP stage. Subclinical CME is seen in premature infants; however, CME does not appear to be correlated with ROP stage. This suggests that there maybe other etiologies for the CME seen in this patient population. Hand-held SD-OCT imaging is a viable technique for evaluating subclinical macular findings in premature infants, though larger datasets are needed from multiple centers to further evaluate the generalizability of these findings.