Multimode fiber as a tool to reduce cross talk in Fourier-domain full-field optical coherence tomography.

Fourier-domain full-field optical coherence tomography (FD-FF-OCT) is an emerging tool for high-speed eye imaging. However, cross-talk formation in images limits the imaging depth. To this end, we have recently shown that reducing spatial coherence with a fast deformable membrane can suppress the noise but over a limited axial range and with substantial data processing. Here, we demonstrate that a multimode fiber with carefully chosen parameters enables cross-talk-free imaging over a long axial range and without significant artifacts. We also show that it can be used to image the human retina and choroid in vivo with exceptional contrast.

SAFETY AND THERAPEUTIC EFFECTS OF ORALLY ADMINISTERED AKST4290 IN NEWLY DIAGNOSED NEOVASCULAR AGE-RELATED MACULAR DEGENERATION.

PURPOSE: To evaluate the safety and therapeutic effects of orally administered AKST4290 (formerly BI 144807 and ALK4290) in treatment-naive patients with neovascular age-related macular degeneration. METHODS: In this prospective, multicenter, open-label Phase 2a pilot clinical study, 30 patients with newly diagnosed neovascular age-related macular degeneration self-administered AKST4290 (400 mg) orally twice daily for 6 weeks. Patients were examined weekly for safety, to measure best-corrected visual acuity (BCVA), and to perform exploratory morphologic assessments. The primary endpoint was the mean change in BCVA from baseline to end of treatment, and the secondary endpoint was safety. Exploratory endpoints investigated potential changes in macular morphology. RESULTS: Mean BCVA improved by +7.0 letters (95% CI, 2.2-11.7); 24 patients (82.8%) had stable or improved BCVA, with 6 (20.7%) gaining ≥15 letters. No patients experienced severe or serious adverse events. CONCLUSION: In this 6-week study, AKST4290 treatment was associated with improved BCVA scores in patients with treatment-naive neovascular age-related macular degeneration. All adverse events were mild or moderate in severity and no safety issues were identified. Treatment of neovascular age-related macular degeneration with AKST4290 warrants further investigation in randomized, placebo-controlled trials.

Optical coherence tomography in diagnosis and monitoring multiple sclerosis.

This paper presents application of optical coherence tomography (OCT) for diagnosis and monitoring of multiple sclerosis (MS). The peripapillary retinal nerve fibre layer thinning and the reduced total macular volume analysis are shown. With the course of the MS, the severity of these abnormalities increases which reflects the progressive degeneration of retinal ganglion cells and nerve fibres. The OCT parameters are sensitive, non-invasive indicators useful in assessing the progression of inflammation and neurodegeneration in MS.

Use of nonsteroidal anti-inflammatory drugs in diabetic retinopathy.

INTRODUCTION: Diabetic macular edema, a manifestation of diabetic retinopathy, occurs more frequently in type 2 diabetes mellitus. There is evidence that inflammation plays a prominent role in the pathogenesis. A number of pro-inflammatory cytokines are consistently elevated in the vitreous of patients with advanced stages of diabetic retinopathy. Nonsteroidal anti-inflammatory drugs inhibit the catalytic activity of the cyclooxygenase isoenzymes COX-1 and COX-2, the key enzymes in inflammatory processes. PURPOSE: To present current knowledge of benefits and limitations of using nonsteroidal anti-inflammatory drugs in diabetic retinopathy. CONCLUSIONS: Nonsteroidal anti-inflammatory druds may be considered as an adjuvant treatment in diabetic retinopathy especially in patients with diabetic macular edema.

Spectral optical coherence tomography vs. fluorescein pattern for rigid gas-permeable lens fit.

BACKGROUND: This study aimed to evaluate anterior segment spectral optical coherence tomography (AS SOCT) for assessing the lens-to-cornea fit of rigid gas-permeable (RGP) lenses. The results were verified with the fluorescein pattern method, considered the criterion standard for RGP lens alignment evaluations. MATERIAL AND METHODS: Twenty-six eyes of 14 patients were enrolled in the study. Initial base curve radius (BCR) of each RGP lens was determined on the basis of keratometry readings. The fluorescein pattern and AS SOCT tomograms were evaluated, starting with an alignment fit, and subsequently, with BCR reductions in increments of 0.1 mm, up to 3 consecutive changes. AS SOCT examination was performed with the use of RTVue (Optovue, California, USA). RESULTS: The average BCR for alignment fits, defined according to the fluorescein pattern, was 7.8 mm (SD=0.26). Repeatability of the measurements was 18.2%. BCR reductions of 0.1, 0.2, and 0.3 mm resulted in average apical clearances detected with AS SOCT of 12.38 (SD=9.91, p<0.05), 28.79 (SD=15.39, p<0.05), and 33.25 (SD=10.60, p>0.05), respectively. CONCLUSIONS: BCR steepening of 0.1 mm or more led to measurable changes in lens-to-cornea fits. Although AS SOCT represents a new method of assessing lens-to-cornea fit, apical clearance detection with current commercial technology showed lower sensitivity than the fluorescein pattern assessment.

Current trends in the monitoring and treatment of diabetic retinopathy in young adults.

The diagnosis and treatment of diabetic retinopathy (DR) in young adults have significantly improved in recent years. Research methods have widened significantly, for example, by introducing spectral optical tomography of the eye. Invasive diagnostics, for example, fluorescein angiography, are done less frequently. The early introduction of an insulin pump to improve the administration of insulin is likely to delay the development of diabetic retinopathy, which is particularly important for young patients with type 1 diabetes mellitus (T1DM). The first years of diabetes occurring during childhood and youth are the most appropriate to introduce proper therapeutic intervention before any irreversible changes in the eyes appear. The treatment of DR includes increased metabolic control, laserotherapy, pharmacological treatment (antiangiogenic and anti-inflammatory treatment, enzymatic vitreolysis, and intravitreal injections), and surgery. This paper summarizes the up-to-date developments in the diagnostics and treatment of DR. In the literature search, authors used online databases, PubMed, and clinitrials.gov and browsed through individual ophthalmology journals, books, and leading pharmaceutical company websites.

Towards standardising retinal OCT angiography image analysis with open-source toolbox OCTAVA.

Quantitative assessment of retinal microvasculature in optical coherence tomography angiography (OCTA) images is important for studying, diagnosing, monitoring, and guiding the treatment of ocular and systemic diseases. However, the OCTA user community lacks universal and transparent image analysis tools that can be applied to images from a range of OCTA instruments and provide reliable and consistent microvascular metrics from diverse datasets. We present a retinal extension to the OCTA Vascular Analyser (OCTAVA) that addresses the challenges of providing robust, easy-to-use, and transparent analysis of retinal OCTA images. OCTAVA is a user-friendly, open-source toolbox that can analyse retinal OCTA images from various instruments. The toolbox delivers seven microvascular metrics for the whole image or subregions and six metrics characterising the foveal avascular zone. We validate OCTAVA using images collected by four commercial OCTA instruments demonstrating robust performance across datasets from different instruments acquired at different sites from different study cohorts. We show that OCTAVA delivers values for retinal microvascular metrics comparable to the literature and reduces their variation between studies compared to their commercial equivalents. By making OCTAVA publicly available, we aim to expand standardised research and thereby improve the reproducibility of quantitative analysis of retinal microvascular imaging. Such improvements will help to better identify more reliable and sensitive biomarkers of ocular and systemic diseases.

The diagnostic function of OCT in diabetic maculopathy.

Diabetic maculopathy (DM) is one of the major causes of vision impairment in individuals with diabetes. The traditional approach to diagnosis of DM includes fundus ophthalmoscopy and fluorescein angiography. Although very useful clinically, these methods do not contribute much to the evaluation of retinal morphology and its thickness profile. That is why a new technique called optical coherence tomography (OCT) was utilized to perform cross-sectional imaging of the retina. It facilitates measuring the macular thickening, quantification of diabetic macular oedema, and detecting vitreoretinal traction. Thus, OCT may assist in patient selection with DM who can benefit from treatment, identify what treatment is indicated, guide its implementing, and allow precise monitoring of treatment response. It seems to be the technique of choice for the early detection of macular oedema and for the followup of DM.

[Uveal effusion syndrome complicated by anterior ischemic optic neuropathy and cystoid macular edema]. / Zespól wysiekowy naczyniówki powiklany przednia niedokrwienna neuropatia nerwu wzrokowego oraz torbielowatym obrzekiem plamki.

The current paper presents a case of unique presentation of idiopathic uveal effusion syndrome. The 28 years old patient with combined bilateral choroidal and retinal detachment, recurrent in the left eye, underwent surgical procedures. He was treated with lamellar sclerectomy under the scleral flap in both eyes and another sclerectomy in the left eye later on. The apposition of the retina was achieved in both eyes and visual acuity improved significantly. Three months later, the patient developed anterior ischemic optic neuropathy in the right eye. In left eye after cataract phacoemulsification, persisted cystoid macular edema appeared.

[Idiopathic juxtafoveolar teleangiectasia 2a in spectral domain optical coherence tomography (SdOCT)]. / Idiopatyczne teleangiektazje okolodoleczkowe typu 2a w obrazie spektralnej optycznej koherentnej tomografii (SOCT).

PURPOSE: The aim of the study was the evaluation of the changes characteristic for type 2a idiopathic juxtafoveal retinal telangiectasia in spectral domain optical coherence tomography images. MATERIAL AND METHODS: The study covered 23 eyes with diagnosed idiopathic juxtafoveal retinal telangiectasia of type 2a - 5 men and 7 women. Stage 2 was noticed in 9 eyes, stage 3 in 5 eyes, stage 4 in 8 eyes. Stage 5 was noticed in one eye. All the patients included in the study underwent the macula analysis by SdOCT technique. RESULTS: Stage 2 was characterized mainly by the occurrence of small hyporeflective microcysts (in 100% of cases), tiny hyperreflective deposits (in 90% of patients), focal retinal photoreceptor layer damage (in 80%) as well as large hyporeflective cysts (70%). Stage 3 in SdOCT scans showed dominating hyperreflective deposits, including both small ones (100%) and less frequent large shaded deposits (71%), and still numerous microcysts (86%) and larger hyporeflective compartments. Stage 4 was characterized by the occurrence of large spreaded areas of fading retinal photoreceptor layer (in 100% of examined eyes), accompanied by retina architecture disorders. We also noticed numerous tiny hyperreflective deposits (100% of examined eyes), as well as large hyperreflective deposits (80%). Microcysts occurred significantly less frequently than in other stages (60%). The average retina thickness in fovea in all eyes irrespective of the stage of disease amounted to 192.13 +/- 59.1 microm, on the other hand in the nasal and temporal parts of fovea 202.43 +/- 37.75 microm and 262.7 +/- 41.31 microm respectively (p< 0.05). CONCLUSIONS: Thanks to its high resolution, SdOCT examination depicts changes in retina in the course of idiopathic juxtafoveal telangiectasia in great detail. Our study shows certain permanent changes occurring in this disease, characteristic to subsequent stages which allow to make a highly probable diagnosis before fluorescein angiography is carried out.

Simultaneous Corneal Topography and Epithelial Thickness Mapping from a Single Measurement Using Optical Coherence Tomography.

Purpose: To evaluate the performance of corneal epithelial thickness mapping (ETM) and demonstrate simultaneous measurement of ETMs and corneal topography using REVO NX (Optopol Technology, Zawiercie, Poland)-an OCT device for anterior and posterior segment imaging. Methods: One hundred thirty-seven eyes of 137 normal subjects and patients with corneal diseases were recruited to the study. Each subject was scanned with REVO NX. ETMs and corneal topography maps were reconstructed from a single measurement. Corneal topography was also carried out using Pentacam (Oculus, Wetzlar, Germany). One hundred twenty-eight eyes were qualified for the final analysis. Forty healthy eyes were used to evaluate the performance of ETM, and 88 eyes were used to compare ETMs and corneal topography. The repeatability and reproducibility of ETMs in healthy subjects were assessed on the basis of 17 spatial zones derived from an 8-mm diameter corneal scan using within-subject standard deviation, test-retest repeatability, within-subject coefficient of variation (CoV), and intraclass correlation coefficient (ICC). Results: The ICC for both repeatability and reproducibility of ETMs for the central sector was 0.95. The ICC value for the other sectors was only moderately lower. However, the CoV for repeatability (≤1.55%) was slightly higher than the value reported for the RTVue device (Optovue, Inc, Fremont, California, USA), for which a CoV in the central zone of 1.07% was reported in unoperated eyes. The superior quadrants were found to be the thinnest while the inferior ones were the thickest. ETMs and topography maps created from a single OCT measurement present a complementary image of the cornea. Conclusions: ETMs obtained using REVO NX show high levels of repeatability and reproducibility in normal eyes. Because the topographic and epithelial thickness analyses are performed using the same data, which means they are based on the exact same 3D corneal model, they do not require reciprocal centration and map matching. This ensures a complete point-to-point correlation between ETMs and corneal topography maps, which paints a fuller picture of a given pathology.

Split-Window OCT biometry in pseudophakic eyes.

PURPOSE: To determine the utility of Split-Window optical coherence tomography OCT (SW-OCT) biometry in measuring ocular axial dimensions as well as imaging the intraocular lens (IOL) and posterior capsule in pseudophakic eyes. METHODS: Sixty-nine pseudophakic eyes of 69 subjects were enrolled in the study. The results of SW-OCT biometry implemented in the SD OCT device for posterior and anterior segment imaging (REVO NX, Optopol Technology) were compared with those obtained with the SS-OCT-based biometer IOLMaster 700 (Carl Zeiss Meditec). Differences in measurement values between the two biometers were determined using the paired t-test. Agreement was assessed through intraclass correlation coefficients (ICC) and Bland-Altman plots. RESULTS: The correlation between measurements obtained with SW-OCT and SS-OCT was very high (ICC for: axial length (AL) = 1.000; anterior chamber depth (ACD) = 0.997; IOL thickness (IOL LT) = 0.997; central corneal thickness (CCT) = 0.987). The mean AL measurement difference was 0.003 ± 0.021 mm (the 95% LoA ranged from -0.04 to 0.05); the mean ACD difference was -0.009 ± 0.025 mm (95% LoA, -0.06 to 0.04); mean LT difference was 0.001 ± 0.021 mm (95% LoA, -0.04 to 0.04); and mean CCT difference was 1.4 ± 5.4 µm (95% LoA, -9 to 12). CONCLUSION: The study shows small, non-significant differences between the biometric measurements obtained with REVO NX SW-OCT and IOLMaster 700 SS-OCT in pseudophakic eyes. However, SW-OCT offered significantly lower ACD and LT measurement failure rates. With high-resolution imaging, SW-OCT enables accurate assessment of IOL position relative to the posterior capsule and visualization of capsular fibrosis.

Spatio-temporal optical coherence tomography provides full thickness imaging of the chorioretinal complex.

Despite the rapid development of optical imaging methods, high-resolution in vivo imaging with penetration into deeper tissue layers is still a major challenge. Optical coherence tomography (OCT) has been used successfully for non-invasive human retinal volumetric imaging in vivo, advancing the detection, diagnosis, and monitoring of various retinal diseases. However, there are important limitations of volumetric OCT imaging, especially coherent noise and the limited axial range over which high resolution images can be acquired. The limited range prevents simultaneous measurement of the retina and choroid with adequate lateral resolution. In this article, we address these limitations with a technique that we term spatio-temporal optical coherence tomography (STOC-T), which uses light with controlled spatial and temporal coherence and advanced signal processing methods. STOC-T enabled the acquisition of high-contrast and high-resolution coronal projection images of the retina and choroid at arbitrary depths.

In vivo imaging of the human eye using a 2-photon-excited fluorescence scanning laser ophthalmoscope.

BackgroundNoninvasive assessment of metabolic processes that sustain regeneration of human retinal visual pigments (visual cycle) is essential to improve ophthalmic diagnostics and to accelerate development of new treatments to counter retinal diseases. Fluorescent vitamin A derivatives, which are the chemical intermediates of these processes, are highly sensitive to UV light; thus, safe analyses of these processes in humans are currently beyond the reach of even the most modern ocular imaging modalities.MethodsWe present a compact, 2-photon-excited fluorescence scanning laser ophthalmoscope and spectrally resolved images of the human retina based on 2-photon excitation (TPE) with near-infrared light. A custom Er:fiber laser with integrated pulse selection, along with intelligent postprocessing of data, enables excitation with low laser power and precise measurement of weak signals.ResultsWe demonstrate spectrally resolved TPE fundus images of human subjects. Comparison of TPE data between human and mouse models of retinal diseases revealed similarity with mouse models that rapidly accumulate bisretinoid condensation products. Thus, visual cycle intermediates and toxic byproducts of this metabolic pathway can be measured and quantified by TPE imaging.ConclusionOur work establishes a TPE instrument and measurement method for noninvasive metabolic assessment of the human retina. This approach opens the possibility for monitoring eye diseases in the earliest stages before structural damage to the retina occurs.FundingNIH, Research to Prevent Blindness, Foundation for Polish Science, European Regional Development Fund, Polish National Agency for Academic Exchange, and Polish Ministry of Science and Higher Education.

Drusen with accompanying fluid underneath the sensory retina.

PURPOSE: To investigate whether confluent drusen may be accompanied by fluid accumulation underneath the sensory retina and to determine if the detection of subretinal fluid on spectral-domain optical coherence tomography (OCT) in patients with coalescent drusen is indicative of choroidal neovascularization (CNV). DESIGN: Prospective, noncomparative case series. PARTICIPANTS: Seventy-four eyes of 57 patients with large, confluent drusen. METHODS: The retinal structure of patients with coalescent drusen was studied by spectral-domain OCT. Optical coherence tomography reflectivity and outer retina topography maps were created and compared with fluorescein angiography (FA) and indocyanine green angiography (ICGA) images as well as with microperimetry. MAIN OUTCOME MEASURES: Optical coherence tomography-derived retinal morphologic features. RESULTS: What appears to be fluid beneath the sensory retina was found on spectral-domain OCT in 8 eyes of 7 patients. The outer retina topography maps demonstrated that fluid accumulates only in the concavity between clustering soft drusen, not on their outward slopes. The maps also revealed a reduced distance between the retinal pigment epithelium (RPE) and the photoreceptor inner/outer segment (IS/OS) junction over large drusen and tiny elevations of the IS/OS junction around drusen of all sizes. Microperimetry showed decreased retinal light sensitivity at the site of diminished distance between the RPE and the IS/OS junction. Seven eyes of 6 patients who were followed up were found to have no retinal changes other than confluent drusen along with subretinal fluid during the entire observational period (12-27 months). There was no evidence of CNV on FA or ICGA in any of the patients. CONCLUSIONS: Large, confluent drusen may be accompanied by subretinal spaces that appear to be filled with fluid. Specific distribution of the fluid limited to the depression between adjacent drusen may indicate that the cluster of coalescent drusen produces mechanical strain to the outer retinal layers that locally pulls the sensory retina away from its normal position. Consequently, the appearance of fluid within subretinal compartment between coalescent drusen in OCT cross-sectional images may not be a reliable marker for the presence of CNV.

Comparison of Advanced Threshold and SITA Fast Perimetric Strategies.

PURPOSE: To compare the results obtained with two threshold strategies of visual field assessment: Humphrey SITA Fast (SFA) (Carl Zeiss Meditec) and PTS 2000 Advanced Threshold (ADV) (Optopol Technology) in healthy subjects and patients with glaucoma. METHODS: The study sample comprised of 53 healthy volunteers and 69 patients with glaucoma. One eye of each patient was examined with the SFA and ADV strategies. The quantitative comparisons of test duration and global indices were made using correlation coefficients. The sensitivity and specificity of the algorithms were evaluated based on the GHT results and the adjusted Anderson-Patella (A&P) criteria. RESULTS: The ADV test duration was shorter both in healthy subjects (by 5%) and patients with glaucoma (by 18%). The mean differences in MS values between the SFA and the ADV strategies were 1.06 ± 1.13 dB (MSSFA-MSADV) in healthy subjects and 1.00 ± 1.92 dB (MSSFA-MSADV) in patients with glaucoma. The MD index of ADV tests was lower than the SFA in the healthy (-0.74 ± 1.09 dB) (MSSFA-MSADV) and glaucoma group (-0.85 ± 2.19 dB) (MSSFA-MSADV). The mean differences in PSD values determined using both methods were -0.86 ± 0.67 dB (PSDSFA-PSDADV) and -0.53 ± 1.48 dB (PSDSFA-PSDADV) in healthy subjects and patients with glaucoma, respectively. Analysis of receiver operating characteristic curves built from MD and PSD indices show bigger area under curve in SFA than in ADV (0.983 vs.0.968 and 0.986 vs. 0.938, respectively). The GHT-based sensitivity and specificity for the ADV strategy were 92.75% and 77.36%, respectively, as compared to 92.75% and 90.57%, respectively, for the SFA strategy. CONCLUSIONS: Both SFA and ADV enable effective identification of glaucomatous defects within 5 minutes. The ADV strategy, however, is significantly faster. The correlation between the global indices of SFA and ADV is very high. Both strategies offer very high sensitivity when using both GHT and A&P criteria.

In vivo imaging of the human cornea with high-speed and high-resolution Fourier-domain full-field optical coherence tomography.

Corneal evaluation in ophthalmology necessitates cellular-resolution and fast imaging techniques that allow for accurate diagnoses. Currently, the fastest volumetric imaging technique is Fourier-domain full-field optical coherence tomography (FD-FF-OCT), which uses a fast camera and a rapidly tunable laser source. Here, we demonstrate high-resolution, high-speed, non-contact corneal volumetric imaging in vivo with FD-FF-OCT that can acquire a single 3D volume with a voxel rate of 7.8 GHz. The spatial coherence of the laser source was suppressed to prevent it from focusing on a spot on the retina, and therefore, exceeding the maximum permissible exposure (MPE). The inherently volumetric nature of FD-FF-OCT data enabled flattening of curved corneal layers. The acquired FD-FF-OCT images revealed corneal cellular structures, such as epithelium, stroma and endothelium, as well as subbasal and mid-stromal nerves.

Comparison of reflectivity maps and outer retinal topography in retinal disease by 3-D Fourier domain optical coherence tomography.

We demonstrate and compare two image processing methods for visualization and analysis of three-dimensional optical coherence tomography (OCT) data acquired in eyes with different retinal pathologies. A method of retinal layer segmentation based on a multiple intensity thresholding algorithm was implemented in order to generate simultaneously outer retinal topography maps and reflectivity maps. We compare the applicability of the two methods to the diagnosis of retinal diseases and their progression. The data presented in this contribution were acquired with a high speed (25,000 A-scans/s), high resolution (4.5 microm) spectral OCT prototype instrument operating in the ophthalmology clinic.

Analysis of the outer retina reconstructed by high-resolution, three-dimensional spectral domain optical coherence tomography.

BACKGROUND AND OBJECTIVE: A retrospective cross-sectional study was conducted to demonstrate an analysis of an outer retinal layer reconstructed by the three-dimensional and high-speed spectral domain optical coherence tomography (SD-OCT) instrument. PATIENTS AND METHODS: New measurement protocols for SD-OCT and methods of analysis and visualization of the individual segmented retinal layer reconstructed by SD-OCT were proposed. Three contour maps representing mutual distances between the basal part of the retinal pigment epithelium, the junction between the inner and outer segments of photoreceptors, and a reference contour representing the shape of a healthy retina were introduced. RESULTS: The analysis of the outer retina was performed on pathological eyes. Three cases of central serous chorioretinopathy, age-related macular degeneration, and acute zonal occult outer retinopathy are demonstrated. CONCLUSION: Three contour maps reconstructed for clinical cases demonstrate high variability of observed patterns depending on analyzed pathology. The authors believe this can help to present OCT data simultaneously in a more comprehensive and convenient way to assist in everyday clinical diagnosis.

A study of macular hole formation by serial spectral optical coherence tomography.

BACKGROUND: The purpose of this paper is to evaluate changes of the vitreoretinal interface in fellow eyes of eyes with a macular hole and to study early stages of macular hole formation by spectral optical coherence tomography (SOCT). METHODS: A prospective study of 131 consecutive patients with history of macular hole. Serial SOCT examinations were performed on the fellow eyes four times during a 6-month observation period. Progression of foveal changes and formation of macular hole in the fellow eyes were studied. RESULTS: Seven distinct abnormalities in the foveal region were noted in 70 of the fellow eyes (53.4%). Additionally in 18 patients (13.6%) other defects typical for the older population were noted. Gradual evolution to full-thickness macular holes during the 6-month observation period was noted in five eyes. One of these eyes had a previously detected cyst, and four eyes had elevation of the photoreceptor layer. CONCLUSIONS: The high prevalence of macular abnormalities in the fellow eyes particularly epiretinal membranes and vitreous traction with schizis as well as the evolution of these abnormalities over time suggest that diseases of the vitreomacular interface may have similar pathogenesis. Macular hole formation often starts as a triangular elevation of the photoreceptor layer. In some cases, a cyst in the inner retinal layers can be an early step in macular hole formation.