Magnification Characteristic of a ؉90-Diopter Double-Aspheric Fundus Examination Lens

PURPOSE. To investigate the magnification characteristic of the ϩ90-D double-aspheric fundus examination lens for biomicroscopic measurement of the optic disc. METHODS. A calibrated Gullstrand-type model eye adjusted for axial ametropia between Ϫ12.5 and ϩ12.6 D was used to measure the change in magnification of the system with refractive error and variation in fundus lens position. A correction factor p (in degrees per millimeter) at different axial ametropias was also calculated. RESULTS. The total change in magnification of the system from myopia to hyperopia was Ϫ15.1% to ϩ13.7%. When the fundus lens position was altered with respect to the model eye by Ϯ2 mm under myopic conditions, the change in magnification of the system was Ϫ4.8% to ϩ8.1%. In the hyperopic condition the change was Ϫ4.8% to ϩ6.0%. The fundus lens exhibited a linear relationship between p and the degree of ametropia of the model eye and a constant relationship between p and ametropia of Ϫ5 to ϩ5 D. CONCLUSIONS. Axial ametropia has a significant effect on biomicroscopic measurement of the optic disc with the ϩ90-D lens. Therefore, a correction factor (p) was calculated that can be used in calculations for determining true optic disc size. These findings may be important for improving clinical disc biometry. (Invest Ophthalmol Vis Sci. 2002;43:1817-1819 D etermining the actual size of the optic disc is possible by histopathologic study, magnification-corrected photogrammetry, scanning laser ophthalmoscopy, or use of the interference fringe scale. 1-4 However, the aforementioned methods are not applicable in a routine clinical setting. Measurement of the optic nerve head is usually performed at the slit lamp biomicroscope using an auxiliary lens to overcome the high focal convergence of the examined eye. In this study, we investigated the magnification characteristic of a ϩ90-D fundus examination lens over a wide range of ametropia in the center of the image field. MATERIALS AND METHODS A commercially available ϩ90-D double-aspheric fundus lens (Volk Opticals, Mentor, OH) and a calibrated slit lamp biomicroscope with adjustable beam length (model 900; Haag-Streit, Bern-Koeniz, Switzerland) were used for this study. It is well known that the calculation of the true size of an object in the ocular fundus depends on the knowledge of the refraction, corneal curvature, and axial length of the eye (correction factor q, in millimeters per degree) To measure the change in magnification of the system with refractive error and variation in condensing lens position, a curved scale in the form of concentric half circles was fitted with the help of an excimer laser in the center of the artificial fundus surface of a calibrated Gullstrand-type model eye. This scale has to be curved, because the optics of the slit lamp biomicroscope and fundus lens are designed for use with a curved field, so that a flat scale is only approximate to the retina in practice. An image of the scale has recently been published. The fundus object was viewed with the fundus lens as in a routine examination of the optic nerve head. The instruments were aligned perpendicularly to the model eye's cornea, and the fundus object was brought into focus by moving the biomicroscope away from the condensing lens until a sharp image of the fundus object was provided in the center of view. A narrow slit beam, with width maintained at 0.2 mm, was progressively reduced in size from 8 mm until it coincided with the diameter of the smallest half circle, which has a true size of 4 mm. The beam length was then recorded, by the second observer, from the millimeter scale at the top of the instrument. Because the slit lamp beam length is calibrated in 0.1 mm, the reading was judged to the nearest 0.05 mm. After each reading, the millimeter scale was reset to 8 mm. Measurements were taken with the vitreous depth of the model eye set at a range of ocular refractions from Ϫ12.5 to ϩ12.6 D. The pupil diameter was 8.0 mm. At each ametropia setting, three measurements were obtained. By dividing the measured length by four, we obtained the actual magnification of the fundus image at the different axial ametropia settings, and by the formula p ϭ (k/17.453)(t/s), where k is the ametropia of the eye ϩ equivalent power of the eye, t is the fundus object size (4 mm), and s is its measured size on the slit lamp biomicroscope, we calculated the fundus lens correction factor p. 7 Measurements were repeated at a separate session, and the 95% confidence interval for repeatability was calculated. 9 To investigate the change in magnification of the system and the correction factor p with variation in condensing lens position, measurements of the fundus object size were obtained as described when the fundus lens position was altered by Ϯ2 mm relative to the model eye's cornea under myopic and hyperopic conditions. RESULT

Choroidal Haller's and Sattler's Layer Thickness Measurement Using 3-Dimensional 1060-nm Optical Coherence Tomography

Objectives: To examine the feasibility of automatically segmented choroidal vessels in three-dimensional (3D) 1060-nmOCT by testing repeatability in healthy and AMD eyes and by mapping Haller's and Sattler's layer thickness in healthy eyes Methods: Fifty-five eyes (from 45 healthy subjects and 10 with non-neovascular age-related macular degeneration (AMD) subjects) were imaged by 3D-1060-nmOCT over a 36°x36° field of view. Haller's and Sattler's layer were automatically segmented, mapped and averaged across the Early Treatment Diabetic Retinopathy Study grid. For ten AMD eyes and ten healthy eyes, imaging was repeated within the same session and on another day. Outcomes were the repeatability agreement of Haller's and Sattler's layer thicknesses in healthy and AMD eyes, the validation with ICGA and the statistical analysis of the effect of age and axial eye length (AL) on both healthy choroidalsublayers. Results: The coefficients of repeatability for Sattler's and Haller's layers were 35% and 21% in healthy eyes and 44% and 31% in AMD eyes, respectively. The mean±SD healthy central submacular field thickness for Sattler's and Haller's was 87±56 µm and 141±50 µm, respectively, with a significant relationship for AL (P<.001). Conclusions: Automated Sattler's and Haller's thickness segmentation generates rapid 3D measurements with a repeatability correspondingto reported manual segmentation. Sublayers in healthy eyes thinnedsignificantly with increasing AL. In the presence of the thinned Sattler's layer in AMD, careful measurement interpretation is needed. Automatic choroidal vascular layer mapping may help to explain if pathological choroidal thinning affects medium and large choroidal vasculature in addition to choriocapillaris loss.Macular Vision Research FoundationMedical University of ViennaEuropean Union (project FUN OCT (FP7 HEALTH, contract no. 201880))European Union (FAMOS (FP7 ICT 317744))European Union (FWF-NFN ‘Photoacoustic imaging in biology and Medicine’, Oesterreichische Nationalbank Jubilaumsfonds projekt (14294))National Institutes of Health (U.S.) (NIH R01-EY011289-27)Deutsche Forschungsgemeinschaft (DFG-GSC80-SAOT)Deutsche Forschungsgemeinschaft (DFG-GSC80-SAOT, DFG-HO-1791/11-1)Carl Zeiss Meditec, Inc.FEMTOLASERS (Firm)Christian Doppler Societ

Biomicroscopic Measurement of the Optic Disc with a High-Power Positive Lens

PURPOSE. To compare the magnification properties of four different indirect double aspheric fundus examination lenses for clinical disc biometry. METHODS. Experimental study in a model eye. The relationship between the true size of a fundus object and its image was calculated for each fundus lens for an ametropic range between Ϫ12.5 and ϩ12.6 D using a slit lamp biomicroscope with adjustable beam length. RESULTS. Equations for determining the correction factor p (degrees per millimeter) were calculated for each fundus lens. The factor can be used in calculations to determine true optic disc size. The total change in magnification of the system from myopia to hyperopia was Ϫ21.1% to ϩ24.0% (60-D lens; Volk Opticals, Mentor, OH), Ϫ12.9% to ϩ16.2% (Volk super 66 stereo fundus lens), Ϫ13.2% to ϩ13.9% (Volk 78-D lens), and Ϫ13.3% to ϩ14.0% (Volk super-field NC lens). When the fundus lens position was altered im relation to the model eye by Ϯ2 mm under myopic conditions, the change in magnification of the system was Ϫ4.3% to ϩ5.7% (60-D lens), Ϫ4.6% to ϩ6.1% (66 stereo fundus lens), Ϫ4.9% to ϩ6.3% (78-D lens), and Ϫ5.9% to ϩ7.8% (super-field NC lens). In the hyperopic condition the change was Ϫ2.7% to ϩ3.6%, Ϫ3.4% to ϩ4.5%, Ϫ3.6% to ϩ4.8%, and Ϫ4.5% to ϩ6.0%. CONCLUSIONS. The study has shown that the use of a single magnification correction value for each fundus lens may not be appropriate. These findings have important implications for the way in which calculations for determining the true optic disc size and other structures of the posterior pole are performed using indirect biomicroscopy. (Invest Ophthalmol Vis Sci. 2001;42:153-157) I n 1953, El Bayadi 1 first examined the fundus with a planoconvex lens of approximately ϩ60 D using the slit lamp biomicroscope, but the technique was not widely accepted because of aberration and difficulty of use. With the introduction of the double aspheric 60-D lens in 1982 (Volk Opticals, Mentor, OH), the technique started to gain popularity for routine stereoscopic examination of the posterior pole. Since then, many attempts have been made to determine the true size of the optic disc with several types of high-power positive lenses using indirect ophthalmoscopy. 2-7 The advantages of this technique for determining the true optic disc size are the immediate availability of the results and the reduced costs in instruments and personnel compared with sophisticated techniques such as computer-based analysis of optic disc photographs (planimetry), scanning laser ophthalmoscopy, video-ophthalmography, and simultaneous stereo optic disc photography with digital photogrammetry. In addition, only a few ophthalmologists have access to this expensive equipment for routine clinical work, and optic disc measurement is usually performed at the slit lamp biomicroscope. The purpose of this study was to compare four widely used high-power positive lenses regarding their magnification over a wide range of ametropia in the center of the image field, by using a slit lamp biomicroscope with adjustable beam length. MATERIALS AND METHODS Four commercially available double aspheric fundus lenses (60-D lens, 66 stereo fundus lens, 78-D lens, and super-field NC lens) manufactured by Volk Optical and a calibrated slit lamp biomicroscope (HaagStreit 900; Bern-Koeniz, Switzerland) were used for this study. All lenses provide a stereoscopic view of the fundus and a wide field of view. In the slit lamp biomicroscopy the observation system of the slit lamp is focused at a finite, short distance. The light from the fundus exits the eye parallel (i.e., from optical infinity); therefore, the slit lamp cannot be focused on the fundus. With the use of a high-power positive lens, a real inverted image of the fundus is formed in front of the slit lamp biomicroscope (toward the observer). For clear imagery, the slit lamp is focused on this image

Intraoperative optical coherence tomography assisted analysis of pars Plana vitrectomy for retinal detachment in morning glory syndrome: a case report

Abstract Background The pathogenesis of non-rhegmatogenous retinal detachment (non-RRD) associated with morning glory syndrome (MGS) is not established, as well as best surgical approach to treat RD. Our purpose was to analyse intraoperative optical coherence tomography data (iOCT) in all steps of pars plana vitrectomy (PPV) for non-RRD in MGS, in order to follow pathophysiological aspects of the disease and to understand the tissues behaviour during surgical workflow. Case presentation Intraoperative spectral domain optical coherent tomography (iSD-OCT) assisted PPV using Rescan 700 (Carl Zeiss Meditech, Jena, Germany) with epiretinal membrane (ERM) and internal retinal membrane (ILM) peeling, and air endotamponade was performed on the only eye of a 21 years old female with non-RRD associated with MGS. BCVA, pre-, intra- and postoperative OCT were performed along with standard ocular examination. iOCT video and snapshots were analysed intra- and postoperatively using post-processing approach using graphic software. The progression of non-RRD resulted in best corrected visual acuity (BCVA) decrease from 0.8 to 0.2. Triamcinolone enhanced iOCT imaging revealed strong vitreous traction and adhesion above the macula and optic disc. Internal limiting membrane was peeled under iOCT control to prevent the peeling of inner layers of the retinal schisis. No retinal break was detected, and only air endotamponade was performed. The retina reattached during first 4 weeks of follow-up with gradual resolution of intraretinal- and subretinal fluid, and remained stable in 12 months. BCVA improved to 0.8. Conclusion Based on iSD-OCT findings we assume that non-RRD in this case of MGS is caused primarily by the vitreous traction with further possible formation of the retinal breaks. Retinal reattachment reached only with air endotamponade strongly advocates the tractional component of non-RRD and retinal schisis assotiated with MGS. Early PPV for central non-RRD and retinal schisis with the use of iOCT can be performed in more safe and controlled manner and has to be considered to reduce the risk of retinal break formation and to prevent the central vision loss

Long-Term Effect of Half-Fluence Photodynamic Therapy on Fundus Autofluorescence in Acute Central Serous Chorioretinopathy

Purpose. To evaluate normalized short-wavelength fundus autofluorescence (SW-FAF) imaging changes over time as a predictive parameter for the retinal pigment epithelium (RPE) function in eyes compromised by acute central serous chorioretinopathy (CSCR) after indocyanine green angiography-guided verteporfin (Visudyne®, Novartis Pharma, Basel, Switzerland) photodynamic therapy (PDT) with a half-fluence rate (25 J/cm2). Methods. Quantitative data of SW-FAF grey values (SW-FAF GV) from a 350 μm (SW-350) and 1200 μm (SW-1200) diameter circle centered on the fovea and normalized with the level of SW-FAF GV in a 30° image of 20 eyes in 11 patients initially treated for unilateral acute symptomatic CSCR were collected and retrospectively analyzed after 7 years. A 2-sided t-test was calculated to explore the differences of SW-350 and SW-1200 between one month and the long-term follow-up. Results. Mean differences (95% CI) in SW-FAF GV between 1 month and 7 years after half-fluence PDT were 0.07 ± 0.11 for SW-350 ([95% CI: −0.002; 0.14], p=0.06) and 0.11 ± 0.15 for SW-1200 ([95% CI: 0.01; 0.21], p=0.03). Mean differences in SW-FAF GV of the contralateral untreated eye were 0.06 ± 0.14 for SW-350 ([95% CI: −0.04; 0.17], p=0.22) and 0.05 ± 0.13 for SW-1200 ([95% CI: −0.04; 0.15], p=0.22). Conclusion. After 7 years, normalized SW-FAF GV were significantly lower in eyes with resolved acute CSCR treated with reduced-fluence PDT compared to the follow-up after 1 month without correlation to explicit pattern changes or structural damages. Half-fluence PDT remains a safe and considerable treatment option in acute CSCR

Seven-Year Visual and Anatomical Outcomes of Intravitreal Vascular Endothelial Growth Factor Inhibition for Neovascular Age-Related Macular Degeneration

Purpose. To evaluate 7-year visual and anatomical outcomes of intravitreal injections (IVI) with antivascular endothelial growth factor (anti-VEGF) for neovascular age-related macular degeneration (nAMD) based on a personalized pro re nata (PRN) regimen. Methods. Anonymized data of 124 consecutive eyes in 121 patients with treatment-naïve nAMD were initially collected in 2010. Of those, 45 received anti-VEGF IVI at least every 6months until 2017 in one single center in Austria and hence were retrospectively analyzed. All eyes had been initiated on a loading dose of 3 monthly IVI with different anti-VEGF agents followed by a PRN regimen in the first year. At year 2, monitoring as well as therapeutic intervention could be prolonged every 2weeks up to intervals of 3months without capping treatment. Primary outcome measure was the change of visual acuity (VA) assessed by Early Treatment Diabetic Retinopathy Study charts at 4 meters (ETDRS) in letters—counting every correctly read letter—and converted to Snellen. Secondary outcome measures were number of injections and change of central retinal thickness (CMT) from baseline. Results. Mean baseline VA was 20/63 + 1 (0.63 ± 0.26 ETDRS) and declined to 20/100 + 2 (0.45 ± 0.33) with an overall loss of 9 letters ETDRS after 7years (p = 0.001). An average of 3.5 ± 1.9 IVI was given per year and eye. Mean CMT at baseline was 322 ± 95 μm, decreased by 52 μm to 270 ± 70 μm within the first year, and remained below baseline at year 7 (271 ± 106 μm; p<0.001). Conclusions. Our data confirm an absolute vision loss in eyes compromised by nAMD after 7 years of continuous VEGF inhibition. The visual decline was significantly related to baseline VA as well as the number of injections. We suggest following patients thoroughly independent of the initial VA and a greater incentive for the physician to treat

Choroidal Thinning in Diabetes Type 1 Detected by 3- Dimensional 1060 nm Optical Coherence Tomography

PURPOSE. To map choroidal (ChT) and retinal thickness (RT) in patients with diabetes type 1 with and without maculopathy and retinopathy in order to compare them with healthy subjects using high speed 3-dimensional (3D) 1060 nm optical coherence tomography (OCT). METHODS. Thirty-three eyes from 33 diabetes type 1 subjects (23-57 years, 15 male) divided into groups of without pathology (NDR) and with pathology (DR; including microaneurysms, exudates, clinically significant macular-oedema and proliferative retinopathy) were compared with 20 healthy axial eye length and age-matched subjects (24-57 years, 9 male), imaged by high speed (60.000 A-scans/s) 3D 1060 nm OCT performed over 368 3 368 field of view. Ocular health status, disease duration, body mass index, haemoglobin-A1c, and blood pressure (bp) measurements were recorded. Subfoveal ChT, and 2D topographic maps between retinal pigment epithelium and the choroidal/scleralinterface, were automatically generated and statistically analyzed. RESULTS. Subfoveal ChT (mean 6 SD, lm) for healthy eyes was 388 6 109; significantly thicker than all diabetic groups, 291 6 64 for NDR, and 303 6 82 for DR (ANOVA P &lt; 0.004, Tukey P ¼ 0.01 for NDR and DR). Thinning did not relate to recorded factors (multi-regression analysis, P &gt; 0.05). Compared with healthy eyes and the NDR, the averaged DR ChT-map demonstrated temporal thinning that extended superiorly and temporalinferiorly (unpaired t-test, P &lt; 0.05). Foveal RT and RT-maps showed no statistically significant difference between groups (mean SD, lm, healthy 212 6 17, NDR 217 6 15, DR 216 6 27, ANOVA P &gt; 0.05). CONCLUSIONS. ChT is decreased in diabetes type 1, independent of the absence of pathology and of diabetic disease duration. In eyes with pathology, 3D 1060 nm OCT averaged maps showed an extension of the thinning area matching retinal lesions and suggesting its involvement on onset or progression of disease. (Invest Ophthalmol Vis Sci. 2012;53:6803-6809

The Diagnostic Capability of Swept Source OCT Angiography in Treatment-Naive Exudative Neovascular Age-Related Macular Degeneration

Purpose. To evaluate the capability of swept source-optical coherence tomography angiography (SS-OCTA) in the detection and localization of treatment-naive macular neovascularization (MNV) secondary to exudative neovascular age-related macular degeneration (nAMD). Methods. In this prospective, observational case series, 158 eyes of 142 patients were diagnosed with exudative nAMD using fluorescein (FA) and indocyanine green angiography (ICGA) and evaluated by SS-OCTA in a tertiary retina center (Rudolf Foundation Hospital Vienna, Austria). The main outcome measure was the sensitivity of SS-OCTA compared to the standard multimodal imaging approach. Secondary outcome measure was the anatomic analysis of MNV in relation to the retinal pigment epithelium. Results. En-face SS-OCTA confirmed a MNV in 126 eyes (sensitivity: 79.8%), leaving 32 eyes (20.2%) undetected. In 23 of these 32 eyes (71.9%), abnormal flow in cross-sectional SS-OCTA B-scans was identified, giving an overall SS-OCTA sensitivity of 94.3%. Eyes with a pigment epithelium detachment (PED) ≥ 300 μm had a smaller probability for correct MNV detection (p=0.015). Type 1 MNV showed a trend (p=0.051) towards smaller probability for the correct detection compared to all other subtypes. Other relevant factors for the nondetection of MNV in SS-OCTA were image artifacts present in 3 of 32 eyes (9.4%). SS-OCTA confirmed the anatomic localization of 93 in 126 MNVs as compared to FA (sensitivity: 73.8%). There was no influence of age, gender, pseudophakia, visual acuity, central foveal thickness, or subfoveal choroidal thickness on the detection rate of MNV. Conclusions. SS-OCTA remains inferior to dye-based angiography in the detection rate of exudative nAMD consistent with type 1 MNV and a PED ≥300 µm. The capability to combine imaging modalities and distinguish the respective MNV subtype improves its diagnostic value