Structure and dynamics of photoreceptor sensory cilia.

The rod and cone photoreceptor cells of the vertebrate retina have highly specialized structures that enable them to carry out their function of light detection over a broad range of illumination intensities with optimized spatial and temporal resolution. Most prominent are their unusually large sensory cilia, consisting of outer segments packed with photosensitive disc membranes, a connecting cilium with many features reminiscent of the primary cilium transition zone, and a pair of centrioles forming a basal body which serves as the platform upon which the ciliary axoneme is assembled. These structures form a highway through which an enormous flux of material moves on a daily basis to sustain the continual turnover of outer segment discs and the energetic demands of phototransduction. After decades of study, the details of the fine structure and distribution of molecular components of these structures are still incompletely understood, but recent advances in cellular imaging techniques and animal models of inherited ciliary defects are yielding important new insights. This knowledge informs our understanding both of the mechanisms of trafficking and assembly and of the pathophysiological mechanisms of human blinding ciliopathies.

Measurement of Diurnal Variation in Rod Outer Segment Length In Vivo in Mice With the OCT Optoretinogram.

Purpose: To investigate diurnal variation in the length of mouse rod outer segments in vivo. Methods: The lengths of rod inner and outer segments (RIS, ROS) of dark-adapted albino mice maintained on a 12-hour dark:12-hour light cycle with light onset 7 AM were measured at prescribed times (6:30 AM, 11 AM, 3:30 PM) during the diurnal cycle with optical coherence tomography (OCT), taking advantage of increased visibility, after a brief bleaching exposure, of the bands corresponding to RIS/ROS boundaries and ROS tips (ROST). Results: Deconvolution of OCT depth profiles resolved two backscatter bands located 7.4 ± 0.1 and 10.8 ± 0.2 µm (mean ± SEM) proximal to Bruch's membrane (BrM). These bands were identified with histology as arising from the apical surface of RPE and ROST, respectively. The average length of dark-adapted ROS at 6:30 AM was 17.7 ± 0.8 µm. By 11 AM, the average ROS length had decreased by 10% to 15.9 ± 0.7 µm. After 11 AM, the ROS length increased steadily at an average rate of 0.12 µm/h, returning to baseline length by 23.5 hours in the cycle. Conclusions: The diurnal variation in ROS length measured in these experiments is consistent with prior histological investigations showing that rodent rod discs are phagocytosed by the RPE maximally over several hours around the time of normal light onset. The rate of recovery of ROS to baseline length before normal light onset is consistent with the hypothesis that disc membrane synthesis is fairly constant over the diurnal cycle.

In-vivo longitudinal changes in thickness of the postnatal canine retina.

The objectives of the present work were to assess by spectral domain optical coherence tomography (OCT) the changes in thickness of the outer nuclear layer (ONL), the ONL + photoreceptor inner segment (IS), and the retinal thickness, as a function of age in the normal canine retina. OCT retinal scans extending from the edge of the optic nerve head (ONH) along the superior and inferior meridians were captured in both eyes of 17 normal dogs at age ranging from 4 to 119 weeks. The different parameters along the superior and the inferior regions were determined following manual segmentation using the Heidelberg Eye Explorer software. Changes in thickness with age were modeled using one-phase exponential decay models. In vivo OCT imaging results showed no interocular statistically significant differences in ONL, ONL + IS, and retinal thickness at any age. All three parameters were however found to be statistically significantly thicker in the superior vs inferior retina. A rapid thinning of the three layers occurs in both the superior and inferior retina between 4 and 12 weeks of age, before reaching a plateau at around 20 weeks of age. In conclusion, the ONL, ONL + IS, and retinal thickness of the normal canine retina decrease significantly during the first three postnatal months, and is likely attributed to an overall increase in the eye volume and tangential dispersion of the photoreceptor since early photoreceptor developmental cell death is very limited at that age. Establishment of the natural history of ONL, ONL + IS, and retinal thinning will allow a more accurate assessment of the progression of a retinal degenerative condition as well as facilitate the detection of positive rescue effect of novel retinal therapies evaluated in this large animal model.

Pregnancy-Associated Plasma Protein-aa Regulates Photoreceptor Synaptic Development to Mediate Visually Guided Behavior.

To guide behavior, sensory systems detect the onset and offset of stimuli and process these distinct inputs via parallel pathways. In the retina, this strategy is implemented by splitting neural signals for light onset and offset via synapses connecting photoreceptors to ON and OFF bipolar cells, respectively. It remains poorly understood which molecular cues establish the architecture of this synaptic configuration to split light-onset and light-offset signals. A mutant with reduced synapses between photoreceptors and one bipolar cell type, but not the other, could reveal a critical cue. From this approach, we report a novel synaptic role for pregnancy-associated plasma protein aa (pappaa) in promoting the structure and function of cone synapses that transmit light-offset information. Electrophysiological and behavioral analyses indicated pappaa mutant zebrafish have dysfunctional cone-to-OFF bipolar cell synapses and impaired responses to light offset, but intact cone-to-ON bipolar cell synapses and light-onset responses. Ultrastructural analyses of pappaa mutant cones showed a lack of presynaptic domains at synapses with OFF bipolar cells. pappaa is expressed postsynaptically to the cones during retinal synaptogenesis and encodes a secreted metalloprotease known to stimulate insulin-like growth factor 1 (IGF1) signaling. Induction of dominant-negative IGF1 receptor expression during synaptogenesis reduced light-offset responses. Conversely, stimulating IGF1 signaling at this time improved pappaa mutants' light-offset responses and cone presynaptic structures. Together, our results indicate Pappaa-regulated IGF1 signaling as a novel pathway that establishes how cone synapses convey light-offset signals to guide behavior.SIGNIFICANCE STATEMENT Distinct sensory inputs, like stimulus onset and offset, are often split at distinct synapses into parallel circuits for processing. In the retina, photoreceptors and ON and OFF bipolar cells form discrete synapses to split neural signals coding light onset and offset, respectively. The molecular cues that establish this synaptic configuration to specifically convey light onset or offset remain unclear. Our work reveals a novel cue: pregnancy-associated plasma protein aa (pappaa), which regulates photoreceptor synaptic structure and function to specifically transmit light-offset information. Pappaa is a metalloprotease that stimulates local insulin-like growth factor 1 (IGF1) signaling. IGF1 promotes various aspects of synaptic development and function and is broadly expressed, thus requiring local regulators, like Pappaa, to govern its specificity.

The aging rat retina: from function to anatomy.

In healthy beings, age is the ultimate reason of cellular malfunction and death. In the rat retina, age causes a functional decline and loss of specific neuronal populations. In this regard, controversial conclusions have been reported for the innermost retina. Here, we have studied the albino and pigmented retina for the duration of the rat life-span. Independent of age (21 days-22 months), the electroretinographic recordings and the volume of the retina and its layers are smaller in albinos. Functionally, aging causes in both strains a loss of cone- and rod-mediated responses. Anatomically, cell density decreases with age because the retina grows linearly with time; no cell loss is observed in the ganglion cell layer; and only in the pigmented rat, there is a decrease in cone photoreceptors. In old animals of both strains, there is gliosis in the superior colliculi and a diminution of the area innervated by retinal ganglion cells. In conclusion, this work provides the basis for further studies linking senescence to neurodegenerative retinal diseases.

Electroretinographic Assessment of Inner Retinal Signaling in the Isolated and Superfused Murine Retina.

PURPOSE: Longer-lasting electroretinographic recordings of the isolated murine retina were initially achieved by modification of a phosphate-buffered nutrient solution originally developed for the bovine retina. During experiments with a more sensitive mouse retina, apparent model-specific limitations were addressed and improvements were analyzed for their contribution to an optimized full electroretinogram (ERG). MATERIAL AND METHODS: Retinas were isolated from dark-adapted mice, transferred to a recording chamber and superfused with different solutions. Scotopic and photopic ERGs were recorded with white flashes every 3 minutes. The phosphate buffer (Sickel-medium) originally used was replaced by a carbonate-based system (Ames-medium), the pH of which was adjusted to 7.7-7.8. Moreover, addition of 0.1 mM BaCl2 was investigated to reduce b-wave contamination by the slow PIII component typically present in the murine ERG. RESULTS: B-wave amplitudes were increased by the pH-shift (pH 7.4 to pH 7.7) from 22.9 ± 1.9 µV to 37.5 ± 2.5 µV. Improved b-wave responses were also achieved by adding small amounts of Ba2+ (100 µM), which selectively suppressed slow PIII components, thereby unmasking more of the true b-wave amplitude (100.0% with vs. 22.2 ± 10.7% without Ba2+). Ames medium lacking amino acids and vitamins was unable to maintain retinal signaling, as evident in a reversible decrease of the b-wave to 31.8 ± 3.9% of its amplitude in complete Ames medium. CONCLUSIONS: Our findings provide optimized conditions for ex vivo ERGs from the murine retina and suggest that careful application of Ba2+ supports reliable isolation of b-wave responses in mice. Under our recording conditions, murine retinas show reproducible ERGs for up to six hours.

Postoperative Recovery of Light Sensitivity in Eyes with Rhegmatogenous Retinal Detachment.

PURPOSE: To investigate whether postoperative light sensitivity recovers completely to the level prior to the development of rhegmatogenous retinal detachment (RRD) after successful surgery. METHODS: We retrospectively studied 44 eyes of 44 patients with RRD who were successfully operated and who underwent Humphrey central 30-2 perimetry postoperatively. The averaged total deviation in Humphrey perimetry in the reattached retina was compared with that of the horizontal or vertical counterpart in the preoperatively non-detached retina. RESULTS: The averaged total deviation in the reattached retina was significantly lower than in its counterpart (p < 0.0001). The averaged residual loss of light sensitivity did not correlate with postoperative visual acuity (p = 0.8047) or with its change (p = 0.1242). CONCLUSIONS: Light sensitivity in the detached retina in eyes with RRD does not completely recover after successful surgery.

The contribution of inner and outer retinal photoreceptors to infra-slow oscillations in the rat olivary pretectal nucleus.

A subpopulation of olivary pretectal nucleus (OPN) neurons discharges action potentials in an oscillatory manner, with a period of approximately two minutes. This 'infra-slow' oscillatory activity depends on synaptic excitation originating in the retina. Signals from rod-cone photoreceptors reach the OPN via the axons of either classic retinal ganglion cells or intrinsically photosensitive retinal ganglion cells (ipRGCs), which use melanopsin for photon capturing. Although both cell types convey light information, their physiological functions differ considerably. The aim of the present study was to disentangle how rod-cone and melanopsin photoresponses contribute to generation of oscillatory activity. Pharmacological manipulations of specific phototransduction cascades were used whilst recording extracellular single-unit activity in the OPN of anaesthetized rats. The results show that under photopic conditions (bright light), ipRGCs play a major role in driving infra-slow oscillations, as blocking melanopsin phototransmission abolishes or transiently disturbs oscillatory firing of the OPN neurons. On the other hand, blocking rod-cone phototransmission does not change firing patterns in photopic conditions. However, under mesopic conditions (moderate light), when melanopsin phototransmission is absent, blocking rod-cone signalling causes disturbances or even the disappearance of oscillations implying that classic photoreceptors are of greater importance under moderate light. Evidence is provided that all photoreceptors are required for the generation of oscillations in the OPN, although their roles in driving the rhythm are determined by the lighting conditions, consistent with their relative sensitivities. The results further suggest that maintained retinal activity is crucial to observe infra-slow oscillatory activity in the OPN.

RECOVERY OF FOVEAL PHOTORECEPTOR INTEGRITY AFTER VITRECTOMY IN EYES WITH AN IMPENDING MACULAR HOLE WITH VITREOMACULAR TRACTION SYNDROME.

PURPOSE: To identify factors associated with the recovery of foveal photoreceptor disruption in eyes with an impending macular hole (MH) with vitreomacular traction syndrome after surgery. METHODS: This study comprised 33 consecutive patients who underwent vitrectomy for Stage 1 impending macular hole with disrupted photoreceptor inner segment/outer segment (IS/OS) layer and were followed up for a minimum of 1 year after surgery. Preoperative optical coherence tomography (OCT) parameters were compared between eyes that achieved complete restoration of the IS/OS layer (Group A) and those that did not (Group B). Postoperative serial changes in best-corrected visual acuity (BCVA) and IS/OS disrupted length were also investigated. RESULTS: Smooth and symmetric foveolar contour was restored in 29 eyes (87.9%). Complete recovery of IS/OS disruption was observed in 11 of 33 cases (33.3%, Group A). Group A exhibited a larger percentage of foveal pseudocysts (54.5% vs. 13.6%, P = 0.033) and a smaller mean aperture size (102.1 ± 182.1 µm vs. 241.5 ± 163.8 µm, P = 0.031) than Group B. Postoperatively, Group A revealed a significantly better visual outcome than Group Be, which was the same as Group B, but with the four eyes that developed a full-thickness macular hole excluded. CONCLUSION: Restoration of the foveal photoreceptor layer was more likely to occur in eyes with a foveal pseudocyst and smaller aperture size.

Correlation Between Visual Function and Photoreceptor Integrity in Diabetic Macular Edema: Spectral-Domain Optical Coherence Tomography.

PURPOSE: To evaluate the relationship between visual function and (i) microstructural changes in the fovea of the inner segment-outer segment junction (IS/OS) and (ii) external limiting membrane (ELM) in diabetic macular edema (DME). METHODS: We conducted a retrospective, observational, cross-sectional study of 40 DME patients (61 eyes), all of whom had been treated at Shanghai First People's Hospital. Patients were divided into groups based on integrity of the IS/OS or ELM: IS/OS (+, ± and -) and ELM (+, ± and -). We performed best-corrected visual acuity (BCVA), MP1 microperimetry and spectral-domain optical coherence tomography (SD-OCT) on all patients. Several variables, including IS/OS and ELM integrity, central macular thickness (CMT) and central macular volume (CMV), were evaluated by two observers, each masked to patients' BCVA. Main outcome measures included determination of the association of visual function with SD-OCT results. RESULTS: Significant differences were found between IS/OS (+), IS/OS (±) and IS/OS (-) groups in BCVA (66.88 ± 7.89, 51.60 ± 9.39, 32.64 ± 17.93 letters, p < 0.001); macular sensitivity (MS; 8.21 ± 2.91, 3.55 ± 2.75, 2.72 ± 1.86 dB, p < 0.001); fixation stability within 2° (82.09 ± 12.76, 66.43 ± 29.54, 33.73 ± 29.51%, p < 0.001); and % central fixation (74.87 ± 16.88, 61.39 ± 31.38, 31.64 ± 31.89%, p < 0.001); but no differences were found for CMT (p = 0.069) or CMV (p = 0.069). Results were similar for ELM groups. There were significant differences between ELM (+), ELM (±) and ELM (-) groups in BCVA (64.16 ± 9.49, 50.44 ± 9.83, 32.73 ± 17.98 letters, p < 0.001); MS (7.54 ± 3.22, 3.38 ± 2.38, 2.20 ± 1.72 dB, p < 0.001); fixation stability within 2° (81.48 ± 15.26, 61.12 ± 31.63, 35.00 ± 29.07%, p < 0.001); and % central fixation (75.90 ± 17.33, 55.88 ± 30.94, 30.09 ± 33.00%, p < 0.001); but not for CMT (p = 0.216) or CMV (p = 0.202). There was a strong correlation (r = 0.881, p < 0.001) between ELM and IS/OS integrity for the same patient. Categories of IS/OS showed more severe changes than did those of ELM. CONCLUSIONS: Both IS/OS and ELM integrity correlated positively with visual function in DME patients. Further studies are needed to confirm and validate this relationship.

Recovery of photoreceptor inner and outer segment layer thickness after reattachment of rhegmatogenous retinal detachment.

AIMS: To evaluate the recovery of retinal function and the thicknesses of the photoreceptor inner (IS) and outer segment (OS) layers after a reattachment of a rhegmatogenous retinal detachment (RRD). METHODS: 49 eyes of 49 patients (mean age, 57.4±10.3 years) with successfully reattached RRD were retrospectively studied. Spectral-domain optical coherence tomography was used to obtain images of the foveal area, and the thicknesses of the IS and OS were measured before and 1, 3, 6 and 12 months after surgery. The thicknesses of the corresponding structures of the healthy fellow eye served as control. RESULTS: The thickness of the IS layer was 20.4±5.0 µm and that of the OS layer was 34.4±9.7 at 1 month after surgery, which was significantly thinner than the IS (28.9±2.9) and OS (55.4±5.2) layers of the fellow eyes. The thicknesses gradually increased and were not significantly different from that in the fellow eye at 12 months (IS, 28.4±4.4 µm and OS, 50.7±6.6 µm). The IS and OS thicknesses at 1 month after surgery in eyes that had a decimal visual acuity of 1.0 at 6 months were significantly thicker than those in eyes that had a visual acuity of <1.0. CONCLUSIONS: The increase in the thicknesses of the IS and OS layers of the photoreceptors during the recovery phase of eyes with RRD indicates that the recovery process was slow and gradual. Quantitative analysis of the IS and OS thicknesses may be useful to follow the disease process.

Light regulates the ciliary protein transport and outer segment disc renewal of mammalian photoreceptors.

The outer segment (OS) of the rod photoreceptor is a light-sensing cilium containing ~1,000 membrane-bound discs. Each day, discs constituting the distal tenth of the OS are shed, whereas nascent discs are formed at the base of the OS through the incorporation of molecules transported from the inner segment. The mechanisms regulating these processes remain elusive. Here, we show that rhodopsin preferentially enters the OS in the dark. Photoexcitation of post-Golgi rhodopsins retains them in the inner segment. Disc-rim protein peripherin2/rds enters the OS following a rhythm complementary to that of rhodopsin. Light-dark cycle-regulated protein trafficking serves as a mechanism to segregate rhodopsin-rich and peripherin2/rds-rich discs into alternating stacks, which are flanked by characteristic cytoplasmic pockets. This periodic cytostructure divides the OS into approximately ten fractions, each containing discs synthesized in a single day. This mechanism may explain how the rod photoreceptor balances the quantity of discs added and removed daily.

Inner segment ellipsoid layer restoration after macula-off rhegmatogenous retinal detachment.

Spectral-domain optical coherence tomography (SD-OCT) often reveals prominent outer retinal changes after macula-off rhegmatogenous retinal detachment. Two patients who presented with macula-off retinal detachment underwent surgical repair. Initial postoperative visual acuity was 20/200 in both cases and correlated with a disruption of the central inner segment ellipsoid layer on SD-OCT. On extended follow-up, SD-OCT demonstrated restoration of the inner segment ellipsoid layer in both patients with concurrent improved visual acuity.

TULP1 mutations causing early-onset retinal degeneration: preserved but insensitive macular cones.

PURPOSE: To investigate visual function and outer and inner retinal structure in the rare form of retinal degeneration (RD) caused by TULP1 (tubby-like protein 1) mutations. METHODS: Retinal degeneration patients with TULP1 mutations (n = 5; age range, 5-36 years) were studied by kinetic and chromatic static perimetry, en face autofluorescence imaging, and spectral-domain optical coherence tomography (OCT) scans. Outer and inner retinal laminar thickness were measured and mapped across the central retina. Comparisons were made with results from patients with RD associated with four ciliopathy genotypes (MAK, RPGR, BBS1, and USH2A). RESULTS: The TULP1-RD patients were severely affected already in the first decade of life and there was rapidly progressive visual loss. No evidence of rod function was present at any age. Small central islands showed melanized retinal pigment epithelium by autofluorescence imaging and well-preserved photoreceptor laminar thickness by OCT imaging. There was extracentral loss of laminar architecture and increased inner retinal thickening. Structure-function relationships in residual foveal cone islands were made in TULP1-RD patients and in other retinopathies considered ciliopathies. Patients with TULP1-RD, unlike the others, had greater dysfunction for the degree of foveal structural preservation. CONCLUSIONS: Retinal degeneration with TULP1 mutations leads to a small central island of residual foveal cones at early ages. These cones are less sensitive than expected from the residual structure. The human phenotype is consistent with experimental evidence in the Tulp1 knockout mouse model that visual dysfunction could be complicated by abnormal processes proximal to cone outer segments.

Pupil responses derived from outer and inner retinal photoreception are normal in patients with hereditary optic neuropathy.

We compared the pupil responses originating from outer versus inner retinal photoreception between patients with isolated hereditary optic neuropathy (HON, n = 8) and healthy controls (n = 8). Three different testing protocols were used. For the first two protocols, a response function of the maximal pupil contraction versus stimulus light intensity was generated and the intensity at which half of the maximal pupil contraction, the half-max intensity, was determined. For the third protocol, the pupil size after light offset, the re-dilation rate and re-dilation amplitude were calculated to assess the post-light stimulus response. Patients with HON had bilateral, symmetric optic atrophy and significant reduction of visual acuity and visual field compared to controls. There were no significant mean differences in the response curve and pupil response parameters that reflect mainly rod, cone or melanopsin activity between patients and controls. In patients, there was a significant correlation between the half-max intensity of the red light sequence and visual field loss. In conclusion, pupil responses derived from outer or inner retinal photoreception in HON patients having mild-to moderate visual dysfunction are not quantitatively different from age-matched controls. However, an association between the degree of visual field loss and the half-max intensity of the cone response suggests that more advanced stages of disease may lead to impaired pupil light reflexes.

Pars plana vitrectomy and internal limiting membrane peeling in epimacular membranes: correlation of function and morphology across the macula.

PURPOSE: To analyze the correlation between morphological and functional results 12 months after epiretinal membrane (ERM) surgery. METHODS: 31 eyes from 31 consecutive patients with metamorphopsia and best corrected visual acuity (BCVA) below 20/32 underwent a transconjunctival 23- gauge vitrectomy with ERM and internal limiting membrane peeling. Preoperatively and 3, 6 and 12 months postoperatively, we assessed BCVA, microperimetry (MP-1) and spectral domain optical coherence tomography (SD-OCT). Photoreceptor inner and outer segment (IS/OS) was graded on SD-OCT images and correlated with microperimetry measurements in the fovea and parafoveal region. RESULTS: The postoperative BCVA was significantly better in eyes with an intact IS/OS junction (p < 0.01). In addition, the mean defect depth was postoperatively decreased in the foveal and parafoveal area in eyes with an intact IS/OS junction. A correlation of SD-OCT IS/OS images and microperimetry in eyes with improvement in BCVA of at least 2 lines revealed a statistically significant result for the parafoveal quadrants (p < 0.011 for SD-OCT and p < 0.005 for microperimetry) but not for the foveal area alone. CONCLUSIONS: The IS/OS regeneration in the parafoveal quadrants contributes significantly to the recovery of BCVA following ERM surgery. Consequently, functional and morphological tests of the macular area should not be limited to the fovea but should be extended to the parafoveal region.

Relationship between the second reflective band on optical coherence tomography and multifocal electroretinography in age-related macular degeneration.

PURPOSE: The second hyper-reflective on spectral domain optical coherence tomography (SD-OCT) has been suggested to correlate with the photoreceptor inner segment ellipsoids (ISe). The purpose of our study was to determine the relationship between the intensity of the ISe band and retinal function measured by multifocal electroretinography (mfERG) in patients with early age-related macular degeneration (AMD). METHODS: A high-resolution horizontal line scan through the fovea on SD-OCT and an mfERG recording were performed in one eye of 29 early AMD and 31 control participants. The relative intensity of the ISe band within 1000 µm of the fovea was quantified using ImageJ. The relationships between the relative intensity of the ISe band and the mfERG response parameters (P1 amplitude and implicit time) within the three central hexagons along the horizontal axis were determined. RESULTS: In normal participants, the relative intensity of the ISe band was significantly correlated with age (r = -0.634, P < 0.001) and also exhibited a topographic variation. On average, the relative intensity of the ISe band was significantly lower in patients with early AMD (1.77 ± 0.26) compared to control subjects (1.95 ± 0.27, P < 0.001) of a similar age range. The relative intensity of the ISe band was correlated significantly with the mfERG P1 implicit time (r = -0.745, P < 0.001), but not P1 amplitude (r = 0.144, P = 0.281). CONCLUSIONS: The relative intensity of the ISe band reduced with age and further in early AMD. The relative intensity was significantly correlated with mfERG P1 implicit time.

Long-term chorioretinal changes after photodynamic therapy for chronic central serous chorioretinopathy.

PURPOSE: To evaluate morphological and functional chorioretinal changes 5 years after standard photodynamic therapy (PDT) for chronic central serous chorioretinopathy (CSC). METHODS: A retrospective, nonrandomized study, including patients with chronic CSC treated with standard PDT and followed for at least 60 months. All patients underwent a complete ophthalmological examination, and the location and number of treatments were registered. Five or more years after treatment, subfoveal and non-subfoveal treated areas were evaluated with Spectralis optical coherence tomography and microperimetry. RESULTS: Seventeen eyes of 15 patients were included, with mean age of 48.3 ± 8.4 years and a mean follow-up of 80.6 ± 12.4 months (range from 62 to 104 months). All eyes had neurosensory detachment (NSD) at baseline. Treatment was performed under the fovea in 58.8 % and in a non-foveal area in 41.2 % of the eyes. At the final visit all eyes had resolution of the NSD, with a statistical significant reduction in central macular thickness (p = 0.005) and preserved neuroretinal thickness (p = 0.839). There was a statistical difference between initial and final BCVA (p < 0.001) and a mean gain of 8.4 ± 7.8 letters. Subfoveal morphological changes in external limiting membrane (ELM) and in photoreceptor inner and outer segment junction (IS/OS) were correlated with final BCVA (p = 0.015 and p = 0.014 respectively), but not with the variation of BCVA. There was a statistical correlation between morphological changes in IS/OS line and retinal sensitivity in the central 12° and 2° (p = 0.003 and p = 0.002 respectively). The morphological changes in the subfoveal layers were not dependent on treatment location (p = 0.154, p = 0.644, and p = 1.0 for ELM, IS/OS line, and retinal pigment epithelium respectively). Subfoveal final mean choroidal thickness was 295.1 ± 68.7 µm, and showed no statistical difference from the normal population (p = 0.633). CONCLUSIONS: Morphological and functional chorioretinal changes, observed 5 or more years after standard PDT for chronic CSC, were not correlated with the location of treatment, neither with the progression of visual acuity or with the location of treatment, and are more likely to be related to the disease itself than with the treatment provided.

Recovery of photoreceptor outer segments after anti-VEGF therapy for age-related macular degeneration.

PURPOSE: To evaluate whether the status of the external limiting membrane (ELM) or inner segment/outer segment junction (IS/OS) improves after intravitreal injection of ranibizumab for age-related macular degeneration (AMD). We also evaluated whether the pre-operative values of these parameters are associated with the visual prognosis. METHODS: This was a hospital-based, cross-sectional study. Seventy-six eyes of 76 treatment-naive AMD patients who received three monthly intravitreal injections of ranibizumab followed for more than 6 months with additional as-needed injections were investigated. Spectral domain OCT was used to evaluate the length of ELM, IS/OS, and foveal thickness pre- and post-operatively. Changes of ELM and IS/OS length were evaluated postoperatively. Correlation coefficients between pre-operative parameters and post-operative visual acuity were also analyzed. RESULTS: Significant changes were noted in mean logMAR (0.66 to 0.53), foveal thickness (231.1 to 151.1 µm), and IS/OS length (514.9 to 832.3 µm) after the treatment. ELM length did not improve significantly (1,312.4 to 1,376.7 µm). Restoration of IS/OS occurred where ELM is retained. Although pre-operative ELM length, IS/OS length, and foveal thickness showed correlation with post-operative logMAR (R = -0.51, -0.39, and 0.46, respectively), the most powerful predictive factor for visual prognosis was pre-operative logMAR (R = 0.77, p < 0.001). CONCLUSIONS: IS/OS status improves in response to anti-VEGF therapy but ELM seems to have less plasticity. The status of IS/OS and ELM can be used as prognostic factors but the predictive power is inferior to that of baseline visual acuity.

Basal bodies exhibit polarized positioning in zebrafish cone photoreceptors.

The asymmetric positioning of basal bodies, and therefore cilia, is often critical for proper cilia function. This planar polarity is critical for motile cilia function but has not been extensively investigated for nonmotile cilia or for sensory cilia such as vertebrate photoreceptors. Zebrafish photoreceptors form an organized mosaic ideal for investigating cilia positioning. We report that, in the adult retina, the basal bodies of red-, green-, and blue-sensitive cone photoreceptors localized asymmetrically on the cell edge nearest the optic nerve. In contrast, no patterning was seen in the basal bodies of ultraviolet-sensitive cones or in rod photoreceptors. The asymmetric localization of basal bodies was consistent in all regions of the adult retina. Basal body patterning was unaffected in the cones of the XOPS-mCFP transgenic line, which lacks rod photoreceptors. Finally, the adult pattern was not seen in 7-days-postfertilization (dpf) larvae; basal bodies were randomly distributed in all the photoreceptor subtypes. These results establish the asymmetrical localization of basal bodies in red-, green-, and blue-sensitive cones in adult zebrafish retinas but not in larvae. This pattern suggests an active cellular mechanism regulated the positioning of basal bodies after the transition to the adult mosaic and that rods do not seem to be necessary for the patterning of cone basal bodies.