Ronald C. Gentile

Reproducibility of Retinal Thickness Measurements in Normal Eyes Using Optical Coherence Tomography

BACKGROUND AND OBJECTIVE To determine the reproducibility of retinal thickness measurements in normal eyes using optical coherence tomography (OCT). PATIENTS AND METHODS Multiple 3.20-mm vertical cross-sectional images through the center of fixation of consecutive patients with normal results on ocular examinations were obtained. Each image was divided into seven 320-micron segments. Regional retinal thicknesses for each section were measured using both the manually assisted (requiring observer localization of reflectivity peaks) and the automated modes (observer-independent measurement) of the computer software. RESULTS Eighteen right eyes were studied. The mean coefficient of variation was less than 10% for all locations using the manually assisted method (average standard deviation less than 17 microns [range 9 to 16 microns]). The automated method was less reliable, with a coefficient of variation greater than 10% for locations within 500 microns of fixation. Automated measurements at fixation were the least reproducible because of poor internal limiting membrane reflectivity. CONCLUSION OCT is capable of reproducible measurement of retinal thickness in normal eyes. Computer-driven, automated measurement of retinal thickness within 500 microns of fixation needs to be refined and its reproducibility reassessed in this region.

RETINAL VASCULAR PERFUSION DENSITY MAPPING USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN NORMALS AND DIABETIC RETINOPATHY PATIENTS.

Purpose: To describe a new method of retinal vascular perfusion density mapping using optical coherence tomography angiography and to compare current staging of diabetic retinopathy based on clinical features with a new grading scale based on perifoveal perfusion densities. Methods: A retrospective review was performed on subjects with diabetic retinopathy and age-matched controls imaged with a spectral domain optical coherence tomography system (Optovue XR Avanti, Fremont, CA). Split-spectrum amplitude-decorrelation angiography (SSADA) generated optical coherence tomography angiograms of the superficial retinal capillaries, deep retinal capillaries, and choriocapillaris. Skeletonized optical coherence tomography angiograms were used to create color-coded perfusion maps and capillary perfusion density values for each image. Capillary perfusion density values were compared with clinical staging, and groups were compared using analysis of variance and Kruskal–Wallis analyses. Results: Twenty-one control and 56 diabetic retinopathy eyes were imaged. Diabetic eyes were grouped according to clinical stage. Capillary perfusion density values from each microvascular layer were compared across all groups. Capillary perfusion density values were significantly lower in nearly all layers of all study groups compared with controls. Trend analysis showed a significant decrease in capillary perfusion density values as retinopathy progresses for most layers. Conclusion: Quantitative retinal vascular perfusion density mapping agreed closely with grading based on clinical features and may offer an objective method for monitoring disease progression in diabetic retinopathy.

Combined multiplanar optical coherence tomography and confocal scanning ophthalmoscopy

We demonstrate the clinical application of a multiplanar imaging system that simultaneously acquires en face (C-scan) optical coherence tomography (OCT) and the corresponding confocal ophthalmoscopic images, along with cross-sectional (B-scan) OCT at specifiable locations on the confocal image. The advantages of the simultaneous OCT and confocal acquisition as well as the challenges of interpreting the C-scan OCT images are discussed. Variations in tissue inclination with respect to the coherence wave surface alter the sampling of structures within the depth of the retina, producing novel slice orientations that are often challenging to interpret. We have evaluated for the first time the utility of C-scan OCT for a variety of pathologies, including melanocytoma, diabetic retinopathy, choroidal neovascular membrane, and macular pucker. Several remarkable new aspects of clinical anatomy were revealed using this new technique. The versatility of selective capture of C-scan OCT images and B-scan OCT images at precise points on the confocal image affords the clinician a more complete and interactive tool for 3-D imaging of retinal pathology.

Comparative Study of Intravitreal Bevacizumab (Avastin) versus Ranibizumab (Lucentis) in the Treatment of Neovascular Age-Related Macular Degeneration

Aims: To compare the safety and efficacy of 2 anti-vascular-endothelial-growth-factor agents – bevacizumab (Avastin) versus ranibizumab (Lucentis) – in the treatment of patients with neovascular age-related macular degeneration (AMD). Methods: Retrospective analysis of patients who received intravitreal injections of bevacizumab or ranibizumab for neovascular AMD. Primary outcome measures were best-corrected visual acuity (BCVA) and central foveal thickness (CFT) assessed by Spectral Domain scanning laser ophthalmoscope-optical coherence tomography (SD-OCT). A secondary outcome measure was the report of any adverse events in the 2 groups. Results: The number of injections in the bevacizumab group was 184 (average of 4.7 per eye) compared to 187 in the ranibizumab group (average of 5.5 per eye). The mean logMAR equivalent of BCVA at 1 month after the injection improved by 0.18 in the bevacizumab group (p = 0.009) and by 0.13 in the ranibizumab group (p = 0.004). The average SD-OCT CFT decreased from 325 ± 72 to 300 ± 69 μm in the bevacizumab group (p = 0.016) and from 307 ± 57 to 289 ± 56 μm in the ranibizumab group (p = 0.017). In the bevacizumab group, there was 1 event of lower extremity pain (0.54%) and 1 event of increased arterial blood pressure (0.54%). In the ranibizumab group, there were 2 events of transiently increased intraocular pressure (1.1%) and 1 event (0.53%) of intraocular inflammation following injection. Conclusions: Bevacizumab and ranibizumab treatments resulted in similar gains in visual acuity and reduction in macular thickness, documented each month following injection. Intravitreal bevacizumab appears to be as safe and effective as intravitreal ranibizumab in the treatment of exudative AMD.

Risk Factors for Ciliochoroidal Effusion after Panretinal Photocoagulation

PURPOSE To determine the incidence, duration, and risk factors for ciliochoroidal effusion after panretinal photocoagulation. METHODS Thirty-nine consecutive patients with diabetic retinopathy underwent ultrasound biomicroscopy of both eyes to image the ciliochoroidal space immediately before and 1 day after unilateral argon-green panretinal photocoagulation. Imaging was repeated on days 3, 7, and 14 in patients in whom ciliochoroidal effusion developed. RESULTS Low-lying ciliochoroidal effusions were imaged in 23 (59%) of 39 eyes. Of 23 eyes, effusions resolved in 6 (26%), 12 (52%), and 5 (22%) eyes by 3, 7, and 14 days respectively. The number of laser applications (P = 0.02), shorter axial length (P = 0.01), and percentage of retinal surface area treated (P = 0.02) were associated with systemic hypertension, location of treatment, previous panretinal photocoagulation of cataract surgery, retinal surface area treated, and mean blood pressure before photocoagulation were not associated with effusion. All fellow, untreated eyes remained effusion-free. CONCLUSION Ciliochoroidal effusion develops commonly after panretinal photocoagulation. Limiting the number of laser applications and the percentage of retinal surface area treated reduces the likelihood of this complication. Eyes with shorter axial lengths are at higher risk

Ultrasound Biomicroscopy in Anterior Ocular Trauma

BACKGROUND AND OBJECTIVE The authors investigated the role of ultrasound biomicroscopy after ocular trauma. PATIENTS AND METHODS Ultrasound biomicroscopy was performed in six eyes of six patients at the New York Eye and Ear Infirmary after a variety of traumatic ocular injuries. RESULTS Eyes with angle recession, iridodialysis, cyclodialysis, hyphema, an intraocular foreign body, scleral laceration, and subluxed crystalline lens were imaged without complication. Ultrasound biomicroscopy aided in the diagnosis when visualization was limited by media opacities or distorted anterior segment anatomy. CONCLUSION Ultrasound biomicroscopy is a safe and effective adjunctive tool for the clinical assessment and management of ocular trauma, especially when visualization is limited and multiple traumatic injuries are involved.

Diagnosis of traumatic cyclodialysis by ultrasound biomicroscopy.

BACKGROUND AND OBJECTIVE To evaluate the ability of high-frequency ultrasound biomicroscopy to diagnose traumatic cyclodialyses not evident on clinical examination. PATIENTS AND METHODS Six eyes to six patients with posttraumatic hypotony and/or shallow anterior chamber and suspected cyclodialysis clefts were examined with slit-lamp biomicroscopy, gonioscopy, B-scan ultrasonography, and ultrasound biomicroscopy. Ultrasound biomicroscopy provided high resolution of cross-sectional images of the anterior chamber angle, posterior chamber, and anterior uveal tissue. RESULTS Ultrasound biomicroscopy confirmed the disinsertion of the ciliary body from the scleral spur and associated ciliary body detachment in all eyes. Gonioscopy failed to demonstrate a cyclodialysis cleft in five eyes because of hyphema (two eyes) and abnormal iris architecture (related to trauma) precluding visualization of the angle recess (three eyes). Using information from ultrasound biomicroscopy imagining, one patient underwent a ciliary body reattachment procedure and repair of the cyclodialysis cleft. CONCLUSION Ultrasound biomicroscopy is a noninvasive method that can accurately diagnose the presence of traumatic cyclodialyses and can aid in surgical management. It is particularly useful in the presence of hazy media, hypotony, and/or abnormal anterior segment anatomy.

High-resolution ultrasound biomicroscopy of the pars plana and peripheral retina

OBJECTIVE This study aimed to evaluate the ability and role of ultrasound biomicroscopy in imaging the peripheral retina, pars plana, and anterior choroid. DESIGN The study design was a case series. PARTICIPANTS Seventeen eyes of 17 patients with a variety of clinical diagnoses involving the anterior portion of the posterior segment were studied. INTERVENTION High-frequency (50 MHz), high-resolution (50 microns) ultrasound biomicroscopy was performed. RESULTS Ultrasound biomicroscopy was capable of imaging the peripheral retina, pars plana, and anterior choroid. Images had features consistent with known histopathology. Retinoschisis consisted of one thin hyper-reflective echo and could be differentiated from a retinal detachment, which was thicker and formed a bilayered echo. A choroidal effusion could be identified as an echolucent space within the suprachoroidea, whereas a choroidal hemorrhage was moderately echodense. Inflammatory diseases, such as a sarcoid granuloma, pars planitis, and Haradas disease, were characterized by different forms of uveal thickening. A ciliochoroidal nevus was internally hyporeflective and could be measured accurately and localized. CONCLUSIONS Imaging of the peripheral retina, pars plana, and anterior choroid is possible with ultrasound biomicroscopy and may aid in the diagnosis and management of pathology involving this region.

Prophylactic Treatment of Age-Related Macular Degeneration Report Number 2: 810-Nanometer Laser to Eyes With Drusen: Bilaterally Eligible Patients

BACKGROUND AND OBJECTIVE To determine the prophylactic and therapeutic value of a single subthreshold 810-nanometer laser treatment in patients with high risk drusen as a manifestation of dry age-related macular degeneration in both eyes. PATIENTS AND METHODS The Prophylactic Treatment of Age-related Macular Degeneration study enrolled 1,278 eyes of 639 participants who were 50 years or older with at least 5 drusen 63 microm or more in diameter in each eye. Treatment consisted of the placement of an annular grid of 48 extrafoveal, subthreshold 810-nm diode laser applications centered at but sparing the foveola in one eye of each participant, with the fellow eye serving as a control. Development of choroidal neovascularization and change in best-corrected visual acuity were compared between treated and untreated eyes. RESULTS Subthreshold laser treatment did not decrease the incidence of choroidal neovascularization in treated versus untreated eyes. A modest visual acuity benefit in treated eyes was found at 24 months (1.5 letter difference; P = .04) and in the treated eyes of participants with a baseline visual acuity between 20/32 and 20/63 (4.0 letter difference; P = .0034). However, this treatment effect was not sustained at 3 years. CONCLUSION A single subthreshold 810-nanometer laser treatment to eyes of participants with bilateral high risk drusen is not an effective prophylactic strategy against choroidal neovascularization.

Macular hole formation, progression, and surgical repair: case series of serial optical coherence tomography and time lapse morphing video study

BackgroundTo use a new medium to dynamically visualize serial optical coherence tomography (OCT) scans in order to illustrate and elucidate the pathogenesis of idiopathic macular hole formation, progression, and surgical closure.Case PresentationsTwo patients at the onset of symptoms with early stage macular holes and one patient following repair were followed with serial OCTs. Images centered at the fovea and at the same orientation were digitally exported and morphed into an Audiovisual Interleaving (avi) movie format. Morphing videos from serial OCTs allowed the OCTs to be viewed dynamically. The videos supported anterior-posterior vitreofoveal traction as the initial event in macular hole formation. Progression of the macular hole occurred with increased cystic thickening of the fovea without evidence of further vitreofoveal traction. During cyst formation, the macular hole enlarged as the edges of the hole became elevated from the retinal pigment epithelium (RPE) with an increase in subretinal fluid. Surgical repair of a macular hole revealed initial closure of the macular hole with subsequent reabsorption of the sub-retinal fluid and restoration of the foveal contour.ConclusionsMorphing videos from serial OCTs are a useful tool and helped illustrate and support anterior-posterior vitreofoveal traction with subsequent retinal hydration as the pathogenesis of idiopathic macular holes.