Visual and Topographic Outcomes of Corneal Collagen Cross Linking for Post LASIK Ectasia.

Purpose: To assess the topographic and visual outcomes of corneal cross-linking (CXL) for post-LASIK ectasia. Methods: A retrospective case series of patients who had progressive post-LASIK ectasia, with at least 2 years of follow-up. They had epithelium-off CXL. Topographical and visual changes were recorded. Results: The study included 21 eyes of 11 patients. At month 24, the final logMAR corrected distance visual acuity (CDVA) and spherical equivalent (SE) were stable compared to baseline (0.16, and -2.0 diopter (D), respectively). The final Kmean and Kmax were 42.5 and 47.4 D, respectively. Stability or improvement in CDVA, SE, and Kmax was seen in 17 eyes (81%). Significant corneal thinning was seen (438 vs 457 microns, p = 0.003). Thinning by 2% or more was seen in 12 eyes (57.1%). Failure of CXL was seen in 4 eyes (19%). No other ocular complications were seen. Conclusion: CXL for post LASIK ectasia is a safe and effective modality. Despite corneal thinning, there was stability or improvement in topographic parameters and CDVA over the 2-year follow-up period.

Adjunctive Green Thermal Laser Photocoagulation for Treatment of Resistant Infectious Keratitis.

PURPOSE: To investigate the safety and efficacy of green thermal laser as an adjunctive therapy for the treatment of resistant infectious keratitis (IK) in the Delta region of Egypt. METHODS: A retrospective case series of 150 patients, within a 4 year duration, with resistant IK, who failed to respond to specific medical treatment alone for 7 days, were included. They all received green thermal laser photocoagulation treatment to the cornea as an adjunctive to medical treatment. RESULTS: Forty-eight women and 102 men were included in this study with a mean age of 46.2 ± 7.7 years. Common risk factors associated with IK included trauma by material of plant origin and contact lens wear. The mean duration of healing was 2.87 ± 0.7 weeks. A single session of green thermal laser application was adequate in 138 IK cases (92%), while 12 cases (8%) required an additional session a week later. Supplementary amniotic membrane transplantation (AMT) was required in 26 cases (17.3%). Two patients (1.3%) required tectonic keratoplasty for corneal perforation. The final corrected distance visual acuity (CDVA) was counting fingers (CF) or better in 78 patients (52%). No decrease of CDVA was reported throughout the study. CONCLUSION: Green thermal laser is a safe and effective adjunctive therapy for the treatment of resistant infectious keratitis.

Acanthamoeba Keratitis in Egypt: Characteristics and Treatment Outcomes.

PURPOSE: To study the predisposing factors, clinical manifestations, and treatment outcome of patients with Acanthamoeba keratitis (AK) at Tanta University's Ophthalmology Hospital in Tanta, Egypt. METHODS: A retrospective study of 42 patients (44 eyes) with Acanthamoeba keratitis who had medical records available for review over 4 years. RESULTS: Forty-four eyes of 42 patients were treated for AK over the study period. In 29 eyes (65.8%), AK was related to contact lens wear. Severe ocular pain was the main presenting symptom in 38 eyes (86.3%). The most common ocular signs were radial perineural corneal infiltrates (65.9%), pseudo-dendrites (43.2%), ring infiltrates (45.5%), and diffuse stromal infiltration (59%). Acanthamoeba was detected by culture, smear, and in-vivo confocal microscopy (IVCM) in 25 eyes (56.8%), while in 19 eyes (43.2%) the diagnosis was based solely on the clinical findings. IVCM was effective in detection of Acanthamoeba in cases with early presentation, while culture was more sensitive in late presentation with corneal melting. The mean duration of treatment was 73.3 ± 23.7 days. Surgical intervention in the form of tectonic grafts or amniotic membrane transplant was required in five cases (11.3%) due to progressive corneal thinning and perforation. Seventeen patients (38.6%) had 0.2 or better final best-corrected visual acuity after treatment. CONCLUSION: The diagnosis of AK remains a major challenge for most ophthalmologists. Contact lens abuse is the major risk factor. Early diagnosis and appropriate treatment of AK with biocidal agents can improve the final outcome and help avoid surgical intervention. IVCM is an excellent tool for early diagnosis of AK.

Prevalence and topographical characteristics of keratoconus in patients with refractive errors in the Egyptian delta.

PURPOSE: To study the prevalence of keratoconus (KC) and the topographical characteristics of the affected corneas in patients with refractive errors who were seeking refractive surgery in the Egyptian delta. METHODS: A retrospective study covering four and half years (Jan 2012-June 2016) where the topographical data of 8124 participants were obtained from the records of a refractive center in the Nile delta region, Egypt. The diagnosis of KC was based on the Holladay criteria in one or both eyes, using the Pentacam scans, whereas grading of KC was based on the Amsler-Krumeich classification. RESULTS: The prevalence of KC was 1.12% (91/8124 participants) with 95% confidence interval 0.91-1.3. Of all the affected cases, 5 cases (5.5%) had unilateral, and the other 86 cases (94.5%) had bilateral KC. The affected and unaffected subjects did not show any significant difference regarding gender. Sixty-eight (38.4%) eyes had stage 1 KC, 53 eyes (29.9%) had stage 2, 27 eyes (15.3%) had stage 3, and 29 eyes (16.4%) had stage 4 KC. It was most prevalent (1.2%) among cases with astigmatism (P < 0.001). CONCLUSION: Keratoconus was found in 1.12% of patients seeking refractive surgery, with no gender preference. Most cases had bilateral affection. Astigmatism was the most common refractive error to be associated with keratoconus.

Retinal Thickening and Photoreceptor Loss in HIV Eyes without Retinitis.

PURPOSE: To determine the presence of structural changes in HIV retinae (i.e., photoreceptor density and retinal thickness in the macula) compared with age-matched HIV-negative controls. METHODS: Cohort of patients with known HIV under CART (combination Antiretroviral Therapy) treatment were examined with a flood-illuminated retinal AO camera to assess the cone photoreceptor mosaic and spectral-domain optical coherence tomography (SD-OCT) to assess retinal layers and retinal thickness. RESULTS: Twenty-four eyes of 12 patients (n = 6 HIV-positive and 6 HIV-negative) were imaged with the adaptive optics camera. In each of the regions of interest studied (nasal, temporal, superior, inferior), the HIV group had significantly less mean cone photoreceptor density compared with age-matched controls (difference range, 4,308-6,872 cones/mm2). A different subset of forty eyes of 20 patients (n = 10 HIV-positive and 10 HIV-negative) was included in the retinal thickness measurements and retinal layer segmentation with the SD-OCT. We observed significant thickening in HIV positive eyes in the total retinal thickness at the foveal center, and in each of the three horizontal B-scans (through the macular center, superior, and inferior to the fovea). We also noted that the inner retina (combined thickness from ILM through RNFL to GCL layer) was also significantly thickened in all the different locations scanned compared with HIV-negative controls. CONCLUSION: Our present study shows that the cone photoreceptor density is significantly reduced in HIV retinae compared with age-matched controls. HIV retinae also have increased macular retinal thickness that may be caused by inner retinal edema secondary to retinovascular disease in HIV. The interaction of photoreceptors with the aging RPE, as well as possible low-grade ocular inflammation causing diffuse inner retinal edema, may be the key to the progressive vision changes in HIV-positive patients without overt retinitis.

Significance of the hyperautofluorescent ring associated with choroidal neovascularisation in eyes undergoing anti-VEGF therapy for wet age-related macular degeneration.

AIM: To characterise the presence of a hyperautofluorescent (HAF) ring associated with choroidal neovascularisation (CNV) complex in patients with wet age-related macular degeneration (AMD). METHODS: Fundus autofluorescence images and spectral-domain optical coherence tomography (OCT) scans from 362 eyes with wet AMD were reviewed. The presence and size of an HAF ring associated with the CNV complex was evaluated. A subgroup of 64 treatment-naive eyes with new-onset CNV was studied to analyse the relationship between pretreatment OCT characteristics and the presence of the HAF ring. RESULTS: An HAF ring was present in 38% of the entire cohort of eyes and in 39% of treatment-naive eyes. The presence of the HAF ring was significantly correlated with the extent of baseline subretinal fluid (SRF) on OCT (p=0.0113), the number of antivascular endothelial growth factor (VEGF) injections (p=0.0439) and the number of treatment cycles (p=0.0154). Eyes with an HAF ring were more likely to have disruption of the ellipsoid zone line once the SRF was resolved compared with eyes without an HAF ring (p=0.0002). In multivariate analysis, the best predictors for HAF ring were the baseline area of SRF (p=0.0449) and the number of anti-VEGF treatments received (p=0.0568). CONCLUSIONS: Nearly 40% of wet AMD eyes had an HAF ring. In treatment-naive eyes, the HAF ring had a significant association with SRF and was found as early as the baseline measurement and as long as 18 months after beginning treatment, persisting for up to 6 years after the initial diagnosis. Its association with baseline SRF and disruption of the ellipsoid zone line of the photoreceptors on OCT could indicate continuous stress on the outer retinal structures after exposure to prolonged SRF and/or transmitted autofluorescence from loss of the photoreceptors overlying the retinal pigment epithelium.

12-month results of the standardised combination therapy for diabetic macular oedema: intravitreal bevacizumab and navigated retinal photocoagulation.

AIM: To evaluate the efficacy of a standardised combination therapy for clinically significant diabetic macular oedema using bevacizumab injections followed by navigated laser photocoagulation to stabilise retinal thickness. METHODS: In this pilot study we retrospectively reviewed charts and imaging of 23 eyes treated with the standardised combination regimen. Eyes initially received monthly bevacizumab injections, followed by navigated laser photocoagulation when central retinal thickness (CRT) was <440 µm. Patients were then followed monthly for 12 months. RESULTS: At the time of navigated laser after bevacizumab treatment mean vision gain was +10.4 Early Treatment Diabetic Retinopathy Study letters (p<0.01) and CRT reduction was 146 µm (p<0.001). At 12 months from baseline, the vision gain remained stable at +10.6 Early Treatment Diabetic Retinopathy Study letters (p<0.01), and CRT reduction was stable at 137 µm (p<0.001). At 12 months from laser, the vision gain was 7.8 letters from baseline (p<0.01), with no significant change compared with the gain at 12 months from baseline (p=0.108). At 12 months from laser, CRT reduction was 125 µm from baseline (p<0.001), with no significant change compared with CRT reduction at 12 months from baseline (p=0.601). Total injections needed were 4.4 from baseline to month 12, with 1.3 reinjection needed after laser. 57% of the eyes didn't require injections after laser, while 43% needed two additional injections. CONCLUSIONS: Standardised combination therapy using bevacizumab injections followed by navigated laser treatment for clinically significant diabetic macular oedema demonstrated significant visual gain and CRT reduction after bevacizumab treatment and stabilisation after navigated laser up to 12 months. The number of injections required in 12 months was lower than reported in previous combination studies.

Fluorescein angiography versus optical coherence tomography-guided planning for macular laser photocoagulation in diabetic macular edema.

PURPOSE: To compare laser photocoagulation plans for diabetic macular edema (DME) using fluorescein angiography (FA) versus optical coherence tomography (OCT) thickness map superimposed on the retina. METHODS: Fourteen eyes with DME undergoing navigated laser photocoagulation with navigated photocoagulator had FA taken using the same instrument. Optical coherence tomography central retinal thickness map was imported to the photocoagulator and with same magnification aligned onto the retina. Three retina specialists placed laser spot marks separately on FA and OCT image in a masked fashion. The spots placed by each physician were compared between FA and OCT and among physicians. The area of dye leakage on FA and increased central retinal thickness on OCT of the same eye were also compared. RESULTS: The average number of spots using FA and OCT template was 36.64 and 40.61, respectively (P = 0.0201). The average area of dye leakage was 7.45 mm, whereas the average area of increased central retinal thickness on OCT of the same eye was 10.92 mm (P = 0.013). CONCLUSION: There is variability in the treatment planning for macular photocoagulation with a tendency to place more spots when guided by OCT than by FA. Integration of OCT map aligned to the retina may have an impact on treatment plan once such information is available.

Macular choroidal volume variations in highly myopic eyes with myopic traction maculopathy and choroidal neovascularization.

PURPOSE: To compare the choroidal volume (CV) between emmetropic and highly myopic eyes, and to assess if the presence of myopic fundus abnormalities, myopic traction maculopathy, or choroidal neovascularization affects the CV. METHODS: We retrospectively reviewed imaging studies of 98 eyes of 98 patients who underwent CV measurement on optical coherence tomography. We included 31 emmetropic eyes (Group 1), 36 highly myopic eyes without vitreoretinal or choroidal pathologies (Group 2), 21 highly myopic eyes with traction maculopathy (Group 3), and 10 highly myopic eyes with history of choroidal neovascularization (Group 3). Eyes with chorioretinal atrophy were excluded. Regression analysis was performed to evaluate the correlation between CV and multiple variables. RESULTS: Choroidal volume was lower in Group 2 than in Group 1 (P < 0.001), and in Groups 3 and 4 than in Group 2 (P < 0.001 and P = 0.002, respectively). Age (P = 0.002), axial length (P < 0.001), sex (P = 0.047), staphyloma (P < 0.001), and myopic group (P = 0.05) were independent predictors for the final CV (R = 0.645). In highly myopic eyes, CV decreased by 0.32 mm for every 10 years and by 0.49 mm per millimeter of axial length. CONCLUSION: Choroidal thinning is present in highly myopic eyes compared with emmetropic eyes, and is related to age, axial length, sex, and staphyloma. However, myopic eyes with coexisting myopic traction maculopathy or history of choroidal neovascularization have more severe thinning, likely leading to insufficient metabolic supplementation for the macula.

Temporal pattern of resolution/recurrence of choroidal neovascularization during bevacizumab therapy for wet age-related macular degeneration.

AIM: To characterize temporal pattern of resolution and recurrence of naive choroidal neovascularization (CNV) secondary to wet age-related macular degeneration (AMD) treated with intravitreal bevacizumab on as needed regimen, and to analyze baseline risk factors for CNV resolution or recurrence. METHODS: Ninety-one eyes of 80 patients with newly diagnosed wet AMD were retrospectively studied. All eyes were treated with a round of three monthly intravitreal bevacizumab injections, followed by one additional 'bonus' injection after resolution of CNV activity. During follow-up, eyes were monitored with fluorescein angiography, optical coherence tomography, and best-corrected visual acuity (BCVA). In case of recurrences of CNV activity, eyes were retreated with other rounds of bevacizumab injections following the same treatment protocol. RESULTS: Over a median follow-up of 532d, the median resolution time of CNV activity in the first, second, and third treatment round was 98d, 126d, and 111d, respectively. The median recurrence time for the three rounds was 154d, 126d, and 151d, respectively. No significant difference in resolution time (P=0.09) or in recurrence time (P=0.11) was detected among treatment rounds. Age (P=0.0082) and lens status (P=0.035) were found to be associated with CNV resolution; for every 1-year increase in age there was 4% greater chance of CNV resolution; Phakic eyes demonstrated a 33% better chance to experience CNV resolution than pseudophakic eyes. For CNV recurrence, lens status (P=0.0009) and gender (P=0.0446) were found to be predictive; pseudophakic eyes had a 3.69-fold greater risk to experience recurrence of CNV activity compared to phakic eyes; males had a 2.19-fold greater risk to experience recurrence of CNV activity than females. No significant BCVA changes among three treatment rounds were noted (P=0.56). CONCLUSION: Resolution time and recurrence time of CNV activity were not significantly different among treatment rounds, suggesting absence of tachyphylaxis to bevacizumab. A cautious decision should be made upon discontinuing treatment in wet AMD eyes of younger or pseudophakic patients, which showed slower response to bevacizumab. In addition, wet AMD eyes of male or pseudophakic patients should be evaluated more carefully after stopping the treatment, because they may have early reactivation of the CNV. BCVA was preserved by bevacizumab treatment despite multiple recurrences.

Visual evoked potential characterization of rabbit animal model for retinal prosthesis research.

Visual evoked potentials (VEP) are used to confirm the function of prosthetic devices designed to stimulate retinas with damaged photoreceptors in vivo. In this work, we focus on methods and experimental consideration for recording visual evoked potential in rabbit models and assesses the use for retinal prosthesis research. We compare both invasive and noninvasive methods for recording VEPs, the response of the rabbit retina to various light wavelengths and intensities, focal vs. full field stimulation, and the effect of light bleaching on the retinal response.

A degenerative retinal process in HIV-associated non-infectious retinopathy.

HIV retinopathy is the most common non-infectious complication in the eyes of HIV-positive individuals. Oncotic lesions in the retinal nerve fiber layer, referred to as cotton wool spots (CWS), and intraretinal (IR) hemorrhages are frequently observed but are not unique to this pathology. HIV-positive patients have impaired color vision and contrast sensitivity, which worsens with age. Evidence of inner-retinal lesions and damage have been documented ophthalmoscopically, however their long term structural effect has not been investigated. It has been hypothesized that they may be partially responsible for loss of visual function and visual field. In this study we utilized clinical data, retinal imaging and transcriptomics approaches to comprehensively interrogate non-infectious HIV retinopathy. The methods employed encompassed clinical examinations, fundus photography, indirect ophthalmoscopy, Farmsworth-Munsell 100 hue discrimination testing and Illumina BeadChip analyses. Here we show that changes in the outer retina, specifically in the retinal pigment epithelium (RPE) and photoreceptor outer segments (POS) contribute to vision changes in non-infectious HIV retinopathy. We find that in HIV-positive retinae there is an induction of rhodopsin and other transcripts (including PDE6A, PDE6B, PDE6G, CNGA1, CNGB1, CRX, NRL) involved in visual transduction, as well as structural components of the rod photoreceptors (ABCA4 and ROM1). This is consistent with an increased rate of renewal of rod outer segments induced via increased phagocytosis by HIV-infected RPE previously reported in culture. Cone-specific transcripts (OPN1SW, OPN1LW, PDE6C, PDE6H and GRK7) are uniformly downregulated in HIV positive retina, likely due to a partial loss of cone photoreceptors. Active cotton wool spots and intraretinal hemorrhages (IRH) may not affect photoreceptors directly and the interaction of photoreceptors with the aging RPE may be the key to the progressive vision changes in HIV-positive patients.

A novel navigated laser system brings new efficacy to the treatment of retinovascular disorders.

The laser photocoagulation is now treatment of choice for various retinovascular disorders. Conventional slit-lamp based laser delivery systems have many limitations including, questionable accuracy, need of contact lens with local anesthesia, and inadvertent damage to fovea. Navigated laser system, a fundus camera based laser delivery system with computer based laser planning and laser treatment without contact lens achieves improved patient compliance, improved accuracy, and treatment ease for the physician, efficient panretinal photocoagulation pattern laser, excellent documentation, and advanced laser training. This article compares navigated laser systems with available conventional and PASCAL laser systems based on the literature and personal experience of the authors.

Safety and efficacy of oral fluorescein angiography in detecting macular edema in comparison with spectral-domain optical coherence tomography.

PURPOSE: To evaluate the safety of oral fluorescein angiography (FA) and to compare its efficacy in detection of macular edema (ME) with spectral-domain optical coherence tomography (SD-OCT). METHODS: Results of imaging studies for 1,928 eyes of 1,019 patients who had simultaneously undergone both oral FA and SD-OCT by a confocal laser ophthalmoscope were reviewed. Sensitivity in detecting ME, discrepancy rate, and "kappa" agreement were determined for both the techniques and with eyes stratified by disease diagnosis. RESULTS: No allergic reactions occurred after oral FA. Mild gastric discomfort was noted in <1% of the patients; 1,840 eyes (95.4%) showed concordance between the two techniques, and kappa agreement was 90.3%. For ME, oral FA showed an overall sensitivity of 0.97 and SD-OCT of 0.91. Equivalent sensitivity was found in cases of wet age-related macular degeneration (0.99). Oral FA was more sensitive than SD-OCT in cases of retinovascular diseases. The SD-OCT showed higher sensitivity in cases of macular holes. Detection of ME by SD-OCT was significantly higher in cases of intense leakage on oral FA (P < 0.001). CONCLUSION: Oral FA proved to be a safe and an adequate technique to evaluate ME. It is more sensitive than SD-OCT in detection of ME in cases of retinovascular diseases but can fail to detect ME in cases of macular holes. A noninvasive examination with simultaneous oral FA and SD-OCT may be considered to obtain a comprehensive evaluation of the presence of ME from different pathologies.

Correlation of spectral domain optical coherence tomography characteristics with visual acuity in eyes with subfoveal scarring after treatment for wet age-related macular degeneration.

PURPOSE: Correlating spectral domain optical coherence tomography characteristics with final best-corrected visual acuity (BCVA) in eyes with subfoveal scarring after treatment for wet age-related macular degeneration. METHODS: Seventy-nine eyes from 64 subjects, who developed subfoveal scarring after treatment of wet age-related macular degeneration, were retrospectively studied. Spectral domain optical coherence tomography characteristics were analyzed, including percentage disruption of inner segment/outer segment junction and external limiting membrane, central macular thickness, subfoveal scar thickness, subretinal scar area, and proximity of retina with intact outer structures to the fovea. A multivariate stepwise regression analysis was performed with the final BCVA logarithm of minimum angle of resolution as a response and the above-identified spectral domain optical coherence tomography variables as predictors. RESULTS: There was no correlation between the final BCVA and any of the demographic data, treatment modality received, and central macular thickness. The final BCVA was significantly correlated with the percentage of inner segment/outer segment disruption (P = 0.011), external limiting membrane disruption (P = 0.005), and scar area on spectral domain optical coherence tomography (P = 0.018). Multivariate analysis showed that the baseline BCVA and distance between the fovea and nearest retina with intact outer structures are the most predictive of the final BCVA (R(2) = 0.52). CONCLUSION: Baseline BCVA and integrity of outer retinal structures are good predictors of the final BCVA of wet age-related macular degeneration patients developing scarring after treatment.

Characterization of microaneurysm closure after focal laser photocoagulation in diabetic macular edema.

PURPOSE: To characterize microaneurysm closure following focal laser photocoagulation in diabetic macular edema (DME) using simultaneous fluorescein angiography (FA) and spectral-domain optical coherence tomography (SD-OCT). DESIGN: Retrospective observational case series. METHODS: Leaking microaneurysms (n = 123) were analyzed in eyes (n = 29) with nonproliferative diabetic retinopathy (NPDR) that underwent navigated focal laser photocoagulation in DME and were followed at 3, 6, and 12 months. Closure of diabetic microaneurysms was characterized in detail following focal laser using SD-OCT. RESULTS: Closure rate of microaneurysms by both FA and SD-OCT was 69.9% (84/123), 79.7% (98/123), and 82.9% (102/123) at 3, 6, and 12 months, respectively. Microaneurysm closure rate increased at 6 and 12 months compared to 3 months (P < .003, P < .001). Over half of closed microaneurysms (45/86, 52.3%) left hyperreflective spots while the remaining half (41/86, 47.7%) disappeared without any hyperreflectivity by SD-OCT at 3 months. Hyperreflective spots decreased at 6 (36/99, 36.4%) and 12 months (17/102, 16.7%) with a concomitant increase in complete loss of reflectivity at 6 (63/99, 63.6%) and 12 months (85/102, 83.3%). Smaller outer and inner diameters and heterogeneous lumen reflectivity were positively associated with microaneurysm closure at 12 months (P < .0001, P < .001, P < .03). CONCLUSIONS: Characterization of microaneurysms following focal laser photocoagulation resulted in hyperreflective spots and complete resolution of all reflectivity using SD-OCT. Smaller microaneurysms and those with heterogeneous lumen were positively associated with microaneurysm closure. These findings provide greater understanding of localized retinal changes following focal laser photocoagulation in DME treatment.

Influence of scanning density on macular choroidal volume measurement using spectral-domain optical coherence tomography.

BACKGROUND: To evaluate the impact of scanning density on macular choroidal volume measurement using spectral-domain optical coherence tomography (SD-OCT). METHODS: Thirty eyes of normal subjects underwent consecutive raster choroidal scanning protocols using SD-OCT in enhanced-depth imaging mode. Manual choroidal segmentation was performed using the built-in automated retinal segmentation software to obtain five analyses with different inter-scan distances, including inter-scan distances of 30 µm, 60 µm, 120 µm, 240 µm, and 480 µm. The built-in software of the device automatically generated the choroidal thickness and volume map in the similar manner as for the retinal volume map, using the standardized Early Treatment Diabetic Retinopathy Study (ETDRS) grid. For each raster scan, mean absolute difference and relative difference of mean foveal choroidal thickness (FCT), foveal choroidal volume (FCV) and total macular choroidal volume (TCV) in comparison to "true value" (i.e., 30-µm inter-scan distance) were calculated. RESULTS: The maximum relative differences were 10% and 16% for TCV and FCV respectively. For mean FCT, the maximum absolute difference was 31 µm, and maximum relative difference was 12.7%. No statistically significant differences were found in measurements of mean foveal choroidal thickness (p = 0.912) and volume (p = 0.944), as well as macular choroidal volume (p = 0.912), with varying inter-scan distance. CONCLUSIONS: Our study shows that approximately 16 scans over the macula with a inter-scan distance of 480 µm is sufficient to provide a clinically relevant and reliable choroidal thickness/volume map. This information could be useful in the design of choroidal scanning protocols for future clinical trials.

Combined depth imaging technique on spectral-domain optical coherence tomography.

PURPOSE: To describe a technique to obtain combined images of vitreoretinal and choroidal structures using spectral-domain (SD) optical coherence tomography (OCT) and to evaluate applicability in normal eyes and limitations in eyes with cataract. DESIGN: Prospective, observational case series. METHODS: Three different foveal scans, including conventional SD OCT, enhanced depth imaging OCT and the novel method called combined depth imaging (CDI) OCT, were obtained in 42 eyes of healthy volunteers and in 26 eyes with cataract using the Heidelberg Spectralis HRA (Heidelberg Engineering). The CDI OCT images were obtained manually using an image modification process that enhances the vitreoretinal interface first and then the choroid, while averaging 100 separate OCT scans. The visualization of the inner border of the preretinal pocket and the outer border of the choroid was graded by independent masked observers for each OCT scan method. RESULTS: The CDI technique was able to create a good-quality combined image of the posterior structures in all the eyes, including eyes with cataract. The agreement between the grading performed by the independent observers was high for both the inner border of the vitreal pocket (κ, 0.86; P < .001) and the outer choroidal border (κ, 0.90; P < .001). CDI OCT was equivalent to conventional SD OCT in visualizing the vitreal pocket (P = .445 for normal eyes, P = .162 for eyes with cataract) and was equivalent to enhanced depth imaging OCT in visualizing the outer choroidal border (P = .660 for normal eyes, P = .329 for eyes with cataract). CDI OCT was superior to conventional SD OCT and enhanced depth imaging OCT in visualizing both of the structures (P < .001). CONCLUSIONS: The manual technique of CDI OCT is highly sensitive to visualize posterior vitreoretinal and choroidal structures into a single full-depth image and is not affected by mild to moderate cataract.

Choroidal volume variations with age, axial length, and sex in healthy subjects: a three-dimensional analysis.

PURPOSE: To demonstrate the 3-dimensional choroidal volume distribution in healthy subjects using enhanced depth imaging (EDI) spectral-domain optical coherence tomography (SD-OCT) and to evaluate its association with age, sex, and axial length. DESIGN: Retrospective case series. PARTICIPANTS: A total of 176 eyes from 114 subjects with no retinal or choroidal disease. METHODS: The EDI SD-OCT imaging studies of healthy patients who had undergone a 31-raster scanning protocol on a commercial SD-OCT device were reviewed. Manual segmentation of the choroid was performed by 2 retinal specialists. A macular choroidal volume map and 3-dimensional topography were automatically created by the built-in software of the device. Mean choroidal volume was calculated for each Early Treatment Diabetic Retinopathy Study (ETDRS) subfield. Regression analyses were used to evaluate the correlation between macular choroidal volume and age, sex, and axial length. MAIN OUTCOME MEASURES: Three-dimensional topography and ETDRS-style volume map of the choroid. RESULTS: Three-dimensional topography of the choroid and volume map was obtained in all cases. The mean choroidal volume was 0.228 ± 0.077 mm(3) for the center ring and 7.374 ± 2.181 mm(3) for the total ETDRS grid. The nasal quadrant showed the lowest choroidal volume, and the superior quadrant showed the highest choroidal volume. The temporal and inferior quadrants did not show different choroidal volume values. Choroidal volume in all the EDTRS rings was significantly correlated with axial length after adjustment for age (P < 0.0001), age after adjustment for axial length (P < 0.0001), and sex after adjustment for axial length (P < 0.05). Choroidal volume decreases by 0.54 mm(3) (7.32%) for every decade and by 0.56 mm(3) (7.59%) for every millimeter of axial length. Male subjects have a 7.37% greater choroidal volume compared with that of female subjects. CONCLUSIONS: Enhanced depth imaging SD-OCT is a noninvasive and well-tolerated procedure with an excellent ability to visualize 3-dimensional topography of the choroid and to measure choroidal volume at the posterior pole using manual segmentation. Age and axial length are inversely correlated with choroidal volume, most likely leading to changes in retinal metabolic support in elderly, highly myopic patients. Sexual differences should be considered when interpreting an EDI SD-OCT scan of the choroid. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Repeatability and reproducibility of manual choroidal volume measurements using enhanced depth imaging optical coherence tomography.

PURPOSE: To evaluate the repeatability and reproducibility of manual choroidal volume (CV) measurements by spectral domain- optical coherence tomography (SD-OCT) using enhanced depth imaging (EDI). METHODS: Sixty eyes of 32 patients with or without any ocular chorioretinal diseases were enrolled prospectively. Thirty-one choroidal scans were performed on each eye, centered at the fovea, using a raster protocol. Two masked observers demarcated choroidal boundaries by using built-in automated retinal segmentation software on two separate sessions. Observers were masked to each other's and their own previous readings. A standardized grid centered on the fovea was positioned automatically by OCT software, and values for average CVs and total CVs in three concentric rings were noted. The agreement between the intraobserver measurements or interobserver measurements was assessed using the concordance correlation coefficient (CCC). Bland-Altman plots were used to assess the clinically relevant magnitude of differences between inter- and intraobserver measurements. RESULTS: The interobserver CCC for the overall average CV was very high, 0.9956 (95% confidence interval [CI], 0.991-0.9968). CCCs for all three Early Treatment Diabetic Retinopathy Study concentric rings between two graders was 0.98 to 0.99 (95% CI, 0.97-0.98). Similarly intraobserver repeatability of two graders also ranged from 0.98 to 0.99. The interobserver coefficient of reproducibility was approximately 0.42 (95% CI, 0.34-0.5 mm(3)) for the average CV. CONCLUSIONS: CV measurement by manual segmentation using built-in automated retinal segmentation software on EDI-SD-OCT is highly reproducible and repeatable and has a very small range of variability.