Horizontal Disc Diameter Research Articles

Myopia and Other Refractive Error and Their Relationships to Glaucoma Screening.

A large disk, a large parapapillary delta zone and a long axial length may be used as screening criteria to detect glaucomatous optic neuropathy in highly myopic eyes. To describe aspects for screening of glaucomatous optic neuropathy in dependence of refractive error, under special consideration of high myopia. Studies on the anatomy of the myopic optic nerve head and results of investigations on the relationship between glaucomatous optic neuropathy and axial myopia were included. In the range from hyperopia to moderate myopia, refractive error is not a strong glaucoma risk factor and may not be included in glaucoma screening strategies. Care should be taken, that in moderate myopia, a shift of Bruch´s membrane opening usually into the temporal direction leads to parapapillary gamma zone and a corresponding shortening of the horizontal disk diameter. In these moderately myopic eyes, a secondarily small optic disk with a correspondingly small optic cup should not lead to an overlooking of intrapapillary glaucomatous changes. Prevalence of glaucomatous or glaucoma-like optic nerve atrophy (GOA) steeply increases with longer axial length in highly myopic eyes (cutoff approximately -8 diopters/axial length 26.5mm), with prevalences higher than 50% in extremely high myopia. Besides longer axial length, morphological parameters associated with GOA in highly myopic eyes are a secondarily enlarged disk and large parapapillary delta zone. Both parameters, together with long axial length, may be used as screening criteria in high myopia for GOA. The latter is characterized by an abnormal neuroretinal rim shape, that is, vessel kinking close to the intrapapillary disk border. Factors associated with nonglaucomatous optic neuropathy are larger gamma zone and longer axial length, potentially due to an axial elongation-related retinal nerve fiber stretching.

Clinical and histological characteristics of axial myopia

Myopic axial elongation is associated with various non‐pathological changes. These include a decrease in photoreceptor cell and retinal pigment epithelium (RPE) cell density and retinal layer thickness, mainly in the retro‐equatorial to equatorial regions; choroidal and scleral thinning pronounced at the posterior pole and least marked at the ora serrata; and a shift in Bruch's membrane opening (BMO) occurring in moderately myopic eyes and typically in the temporal/inferior direction. The BMO shift leads to an overhang of Bruch's membrane (BM) into the nasal intrapapillary compartment and BM absence in the temporal region (i.e., parapapillary gamma zone), optic disc ovalization due to shortening of the ophthalmoscopically visible horizontal disc diameter, fovea–optic disc distance elongation, reduction in angle kappa, and straightening/stretching of the papillomacular retinal blood vessels and retinal nerve fibres. Highly myopic eyes additionally show an enlargement of all layers of the optic nerve canal, elongation and thinning of the lamina cribrosa, peripapillary scleral flange (i.e., parapapillary delta zone) and peripapillary choroidal border tissue, and development of circular parapapillary beta, gamma, and delta zone. Pathological features of high myopia include development of macular linear RPE defects (lacquer cracks), which widen to round RPE defects (patchy atrophies) with central BM defects, macular neovascularization, myopic macular retinoschisis, and glaucomatous/glaucoma‐like and non‐glaucomatous optic neuropathy. BM thickness is unrelated to axial length. Including the change in eye shape from a sphere in emmetropia to a prolate (rotational) ellipsoid in myopia, the features may be explained by a primary BM enlargement in the retro‐equatorial/equatorial region leading to axial elongation.

Myopia: Histology, clinical features, and potential implications for the etiology of axial elongation.

Myopic axial elongation is associated with various non-pathological changes. These include a decrease in photoreceptor cell and retinal pigment epithelium (RPE) cell density and retinal layer thickness, mainly in the retro-equatorial to equatorial regions; choroidal and scleral thinning pronounced at the posterior pole and least marked at the ora serrata; and a shift in Bruch's membrane opening (BMO) occurring in moderately myopic eyes and typically in the temporal/inferior direction. The BMO shift leads to an overhang of Bruch's membrane (BM) into the nasal intrapapillary compartment and BM absence in the temporal region (i.e., parapapillary gamma zone), optic disc ovalization due to shortening of the ophthalmoscopically visible horizontal disc diameter, fovea-optic disc distance elongation, reduction in angle kappa, and straightening/stretching of the papillomacular retinal blood vessels and retinal nerve fibers. Highly myopic eyes additionally show an enlargement of all layers of the optic nerve canal, elongation and thinning of the lamina cribrosa, peripapillary scleral flange (i.e., parapapillary delta zone) and peripapillary choroidal border tissue, and development of circular parapapillary beta, gamma, and delta zone. Pathological features of high myopia include development of macular linear RPE defects (lacquer cracks), which widen to round RPE defects (patchy atrophies) with central BM defects, macular neovascularization, myopic macular retinoschisis, and glaucomatous/glaucoma-like and non-glaucomatous optic neuropathy. BM thickness is unrelated to axial length. Including the change in eye shape from a sphere in emmetropia to a prolate (rotational) ellipsoid in myopia, the features may be explained by a primary BM enlargement in the retro-equatorial/equatorial region leading to axial elongation.

Quantitative Evaluation of Progression of Retinal Vascularization After 60 Weeks Postmenstrual Age in Infants Treated With Bevacizumab.

To investigate the progression of retinal vascularization after 60 weeks postmenstrual age (PMA) in eyes treated with intravitreal bevacizumab (IVB). Twenty-seven eyes that were treated with IVB and underwent two consecutive fluorescein angiographies (FA) after 60 weeks PMA. Horizontal disc diameter (DD), disc-to-fovea (DF) distance, and length of temporal retinal vascularization (LTRV) were measured in pixels on the two consecutive angiograms. Mean age at first and final FA sessions were 77.7 ± 15.7 and 168.0 ± 49.0 weeks PMA, respectively. The DF/DD ratio was 3.30 ± 0.46 and 3.16 ± 0.46 in the first and final FAs (P = 0.001), respectively. The LTRV/DD ratio was 13.38 ± 2.12 and 13.15 ± 2.13 in the first and final FAs (P = 0.027), respectively. The LTRV/DF ratio was 4.06 ± 0.39 and 4.17 ± 0.42, respectively (P = 0.032). Temporal retinal vascularization did not progress despite an average follow-up of 90 weeks in pixel units and DD. [Ophthalmic Surg Lasers Imaging Retina 2023;54:417-424.].

Comparison of optic disc head vascular density status between crowded and normal discs: An optical coherence tomography angiography study.

To compare the optic disc capillary vascular status between crowded and normal optic discs using optical coherence tomography angiography (OCT-A). A total of 101 eyes were included in this cross-sectional, comparative study. Fifty-one eyes with crowded optic discs (Group 1) were compared with 50 eyes with normal discs (Group 2). Peripapillary and optic disc head capillary vascular density measurements were obtained quantitatively with OCT-A. Mean ages were 46.2±6.2 years in Group1 and 45.9±6.0 years in Group2 (p=0.796).Vertical disc diameters were 1.52±0.2mm in Group 1 and 1.61±0.16mm in Group 2 (p=0.022) whereas horizontal disc diameters were 1.53±0.17mm in Group 1 and 1.61±0.13mm in Group 2(p˂0.014). OCT-A findings were as follows: radial peripapillary capillary, vascular density whole image measurements (%); 49.6±2.3 in Group 1 and 49.1±2.3 in Group 2 (p=0.292), peripapillary capillary density; 53.3±2.8 in Group 1 and 52.6±2.6 in Group 2 (p=0.176), inside disc measurements 52.4 (48.7-54.7) in Group 1 and 46.5 (42.6-49.6) in Group 2 (p˂0.001). RNFL was 118.2±12.2µm in Group 1 and 110.8±11.4µm in Group 2(p=0.002). The vascular density of the disc circumference in individuals with healthy crowded optic discs is not different from those with normal discs. However, inside disc measurements differ between crowded and normal size discs. This finding suggests that when the disc size is reduced, the amount of vessels in it does not decrease in a way that correlates with the size. Therefore, the vascular structures are suitable for compression in the narrow optic nerve head.

Anatomic Peculiarities Associated with Axial Elongation of the Myopic Eye.

To describe anatomical peculiarities associated with axial elongation in the human myopic eye. Reviewing the results of previous histomorphometrical investigations of enucleated human globes, as well as reviewing findings obtained in population-based studies and hospital-based clinical investigations of myopic patients and non-myopic individuals. Myopic axial elongation is associated with a change from a mostly spherical eye shape to a prolate ellipsoid form. It is combined with choroidal and scleral thinning, most pronounced at the posterior pole and less pronounced in the fundus midperiphery. In the fundus midperiphery, the retina and density of the retinal pigment epithelium (RPE) and photoreceptors decrease with a longer axial length, while in the macular region, retinal thickness, RPE cell density, and choriocapillaris thickness are not related to axial length. With axial elongation, a parapapillary gamma zone develops, leading to an enlargement of the optic disc-fovea distance and a decrease in angle kappa. Axial elongation is also correlated with an increase in the surface and volume of Bruch's membrane (BM), while BM thickness remains unchanged. Axial elongation causes moderately myopic eyes to show a shift of BM opening to the foveal direction so that the horizontal disc diameter becomes shorter (with a consequent vertical ovalization of the optic disc shape), a temporal gamma zone develops, and the optic nerve exit takes an oblique course. Features of high myopia are an enlargement of the RPE opening (myopic parapapillary beta zone) and BM opening (secondary macrodisc), elongation and thinning of the lamina cribrosa, peripapillary scleral flange (parapapillary delta zone) and peripapillary choroidal border tissue, secondary BM defects in the macular region, myopic maculoschisis, macular neovascularization, and cobblestones in the fundus periphery. These features combined may be explained by a growth in BM in the fundus midperiphery leading to axial elongation.

Quantitative vascular outgrowth and anatomic and refractive outcomes of eyes treated with bevacizumab in posterior zone Ⅰ.

To report the anatomic and refractive outcomes and retinal vascular outgrowth in eyes with posterior zone Ⅰ retinopathy of prematurity (ROP) treated with intravitreal bevacizumab (IVB). Thirty-eight eyes of 21 infants treated with IVB for type 1 and aggressive-ROP, and whose posterior border of retinal vascularization was shorter than the optic disc-to-fovea distance were defined as posterior zone Ⅰ and included in the study. Nine eyes of five infants whose follow-up time was lower than four months were accepted as insufficient for clinical outcomes. Additional treatment(s) had been performed up to 60 weeks postmenstrual age (PMA) in 10 of 29 eyes whose follow-up were higher than four months. Macula was attached at the final examination in all eyes with > 4 months follow-up. Anatomical outcome of two eyes of one infant was accepted as unfavorable whose routine follow-up was interrupted after successful initial treatment and who was presented with straightening of the temporal vascular arcade and residual fibrovascular tractional bands on the temporal periphery. The mean progression of temporal retinal vascularization was 3.6 ± 2.0 horizontal disc diameters (DD) within 7.3 weeks and 5.1 ± 2.5 horizontal DD within 69.1 weeks in the short-term (n=15) and long-term evaluated eyes (n=21), respectively. The mean spherical equivalent was -4.1 diopters at a mean age of 21 months (n=28). A favorable outcome had been achieved in almost all bevacizumab-treated eyes, but additional treatments were required. Significant progression of retinal vascularization was detected even in the eyes with short follow-up.

The retinal vascular growth rate in babies with retinopathy of prematurity could indicate treatment need.

Purpose:To analyze the weekly rate of retinal vascular growth in treatment-naïve babies with various stages of retinopathy of prematurity (ROP) and validate if this could be a predictor of treatment need.Methods:Retrospective review of medical charts and retinal images of babies with various stages of ROP. The images were enhanced using red-green image enhancement software. Using the length of the horizontal disc diameter (DD) of each eye, the vessel growth was measured from the disc margin up to the vessel tip in fixed quadrants. The rate of vessel growth was the ratio of vessel length to the number of weeks it took to reach this length. The babies were divided into treatment warranting ROP (group 1), low-risk pre-threshold (type II) ROP (group 2,), and no-ROP (group 3) for analysis. The “no-ROP” group acted as normal control. Group 1 was further subdivided into 1A (threshold ROP), IB (aggressive posterior ROP), 1C (hybrid ROP), and ID (high-risk pre-threshold ROP).Results:Out of 436 eyes, groups 1, 2, and 3 had 238, 108, and 90 eyes, respectively. The mean rate of vascular outgrowth along with 95% confidence interval (CI) was 0.490 [0.487,0.520], 0.612 [0.599, 0.638], and 0.719 [0.703, 0.740] DD/week, respectively, for babies with “treatment warranting,” “low risk pre-threshold” and “no ROP” groups, respectively. In our estimate, more than 80% of eyes with a vessel growth rate of 0.54 DD/week or less required treatmentConclusion:A rate of retinal vascular growth less than 0.54 DD/week can be used to determine treatment requirements in babies with ROP.

Combining spectral domain optical coherence tomography of retinal nerve fiber layer and noncontact tonometry in mass glaucoma screening during the World Glaucoma Week

This study reports the combination of noncontact tonometry and spectral domain optical coherence tomography (SD-OCT) in mass glaucoma screening in the Lebanese population. This cross-sectional study included Lebanese individuals who participated in a glaucoma screening campaign in March 2018 and March 2019 for World Glaucoma Week. Intraocular pressure (IOP) was measured by noncontact tonometry. Optic nerve head (ONH) and retinal nerve fiber layer (RNFL) scans were obtained using SD-OCT. Glaucoma suspects were defined as individuals having an IOP above 21mmHg in at least one eye and/or RNFL thinning in either the superior or the inferior quadrant. Among the 1116 individuals who were examined, 15.5% were found to be glaucoma suspects based upon their IOP readings, 15.5% based on OCT, and 3.0% based on both criteria combined. The mean vertical and horizontal disc diameter was 1.75±0.23mm and 1.57±0.22mm, respectively. Eyes that were suspects by OCT with normal IOP had thinner corneas when compared to eyes with normal OCT and high IOP (512.25μm vs. 559.12μm, P<0.0001). SD-OCT can be an easy and relatively fast component of mass glaucoma screening in addition to IOP measurement. Further studies are needed to establish this combination as a valid glaucoma screening method.

Inter-eye comparison of retinal vascular growth rate and angiographic findings following unilateral bevacizumab treatment.

To compare retinal vascularization progression rate, final retinal vascularization, and fluorescein angiography (FA) findings in infants who received intravitreal bevacizumab (IVB) treatment in one eye and with spontaneous regression in the other eye. Thirty eyes of 15 infants who underwent IVB in one eye due to asymmetric retinopathy of prematurity, and who had pre-treatment fundus photographs and fluorescein angiography images were included in the study. Horizontal disc diameter (DD), optic disc-to-fovea distance (FD), and the length of temporal retinal vascularization (LTRV) distance were measured by evaluating pre-treatment and FA images. The mean ages at the time of treatment and FA were 40.38 ± 3.35 and 68.72 ± 10.52 weeks postmenstrual age, respectively. The pre-treatment LTRV/FD ratio was 3.11 ± 0.41 in the treated eyes and 3.26 ± 0.43 in the non-treated eyes (p = 0.053). The final LTRV/FD ratio was 4.23 ± 0.38 in the treated group and 4.33 ± 0.37 in the non-treated group (p = 0.286). Staining of the vessels, hyperfluorescent focus, and irregular branching of the vessels were similar between the groups, respectively (p = 1.000; p = 0.250; p = 0.625). The progression rate of retinal vascularization and angiographic findings were similar between the treated eyes and the non-treated eyes. Our study suggests that incomplete retinal vascularization in eyes treated with anti-vascular endothelial growth factor (VEGF) is due to the nature of the disease, and anti-VEGF treatment was not to cause cessation in vascular progression.

The Effect of Intravitreal Bevacizumab Dose on Retinal Vascular Progression in Retinopathy of Prematurity

Introduction: In this study, we investigated the effect of drug dose on the progression of retinal vascularization in eyes treated with different doses of intravitreal bevacizumab (IVB). Methods: The patient charts of 259 eyes of 142 patients who were administered 0.3125 mg or 0.625 mg IVB as primary therapy for type 1 retinopathy of prematurity (ROP) or aggressive ROP (A-ROP) were retrospectively evaluated. Eighty-four eyes of 42 infants met all study inclusion criteria and underwent further morphological evaluation. Eyes treated with 0.3125 mg and 0.625 mg bevacizumab were grouped as the low dose and standard dose groups, respectively. Horizontal disc diameter (DD), optic disc-to-fovea distance (FD), and the length of temporal retinal vascularization (LTRV) were measured on pretreatment photographs (PPs) and final fluorescein angiography (FA) images. LTRV, measured in pixels, was converted to DD and FD units and analyzed. All PPs and FA images were captured with 130° PanoCam Pro camera. The difference between final LTRV and pretreatment LTRV was defined as the difference of LTRV. The ratio of difference of LTRV to pretreatment LTRV was defined as the rate of increase of LTRV. Results: Of the 255 eyes, re-treatment rate before 55 weeks postmenstrual age (PMA) was 23% in the eyes treated with 0.3125 mg IVB and 19% in the eyes treated with 0.625 mg IVB (p = 0.362). Of the 42 infants included for further morphological evaluation, the median age at the time of treatment was 36 (35–38) weeks PMA, and the median age at the time of FA imaging was 66 (62–75) weeks PMA. While the difference of LTRV by unit of DD was higher in the low dose group (p = 0.017), this difference was similar between groups by unit of FD (p = 0.412). The ratio of the increase of the LTRV was similar between groups by units of DD and FD (p = 0.081, p = 0.390; respectively). The FD/DD ratio was 4.13 ± 0.49 and 3.26 ± 0.33 at the pretreatment and final sessions, respectively (p = 0.000). Conclusion: The ratio of FD to DD decreased significantly with increasing age. The additional treatment rate and progression of retinal vascularization by unit of FD were similar between the groups. The difference of LTRV by unit of DD was higher in the low dose group. The usage of dif­ferent formulas and methods may affect the evaluation of the progression of retinal vascularization.

Optic disc morphology in preterm children. Influence of gestational age and birth weight

The characteristics of the optic disc and the development of the optic nerve can affect visual function in children. The purpose of our study was to assess optic disc morphology in preterm infants and to determine whether it is influenced by gestational age, birth weight and the presence of a retinopathy of prematurity. In a retrospective study, RetCam fundus images of 109 premature newborns admitted to our tertiary-level neonatal intensive care unit were reviewed. We evaluated the cup to disc ratio (C/D), optic disc diameter, cup diameter, shape of the optic disc, adherence to the ISNT rule, and presence of a peripapillary atrophy. Of 218 photos, we found the following results: mean±SD gestational age 28.5±2.7 weeks, mean±SD birth weight 1122±394g, mean C/D 0.32. There was no significant correlation between C/D and gestational age or birth weight. Vertical disc diameter was greater than horizontal disc diameter, with a mean ratio (horizontal/vertical) of 4/5, lending an oval shape to the optic disc. Nineteen infants had retinopathy of prematurity in both eyes; ninety-three percent had peripapillary atrophy. In our study, optic disc morphology in premature newborns was not influenced by gestational age, birth weight or presence of premature retinopathy.

Optic disc morphometry using spectral domain optical coherence tomography in a Nigerian population.

To assess morphological optic disc dimensions using spectral-domain optical coherence tomography (OCT) in a Nigerian population. Good quality SD-OCT scans of the optic disc of 147 eyes of 88 participants were selected, enrolled, and retrospectively reviewed. All subjects had optic nerve head and retinal nerve fibre layer OCT imaging, as well as analysis, done using the Topcon 3D OCT-1 Maestro®. The age, sex, and some OCT-generated optic disc dimensions namely disc area (DA), vertical disc diameter (VDD), horizontal disc diameter (HDD) were retrieved from the database and analyzed. The mean age of the study subjects was 52.6±20.9 years with a range of 8-90 years; male to female ratio was 1:1.3. The right eye and left eye accounted for 75 and 72 of the 147 scans respectively. The mean DA, VDD, and HDD were 2.54 ± 0.48 mm2, 1926.5 ± 189.6 μm and 1673.9 ± 173.9 μm, respectively. Males had significantly larger DA than females (2.56 ± 0.53 mm2 vs 2.51 ± 0.44 mm2, p = 0.043). The mean DA and VDD of eyes of subjects aged 21-40 years were significantly higher compared to subjects aged 60 years and more (p = 0.008 and 0.001, respectively). The mean optic disc area and diameters are larger than those reported in similar studies involving blacks and other races. The mean disc area reduces with increasing age.

Correlation between optic disc deformation and retinal vasculature in non-pathological high myopia.

The aim of the current study was to investigate the correlation between optic disc deformation and retinal vasculature in high myopia. A total of 130 eyes with non-pathological high myopia were included in the current cross-sectional study. β-zone parapapillary atrophy (β-PPA), optic disc tilt ratio, and horizontal and vertical disc diameters were analyzed using fundus color photography. A 3x3 mm grid and a 4.5x4.5 mm grid were used to scan parafoveal and peripapillary regions, respectively, using optical coherence tomography angiography. Vessel flow density (VFD) and fractal dimension of the retina, as well as the foveal avascular zone (FAZ), were analyzed and quantified using en face projection images. Optic disc parameters that were associated with vascular changes were determined using multiple linear regression analysis. The results from the multivariate analysis revealed that β-PPA was negatively correlated with the VFD of the superficial retinal plexus (R=-2.805; P=0.006), deep retinal plexus (R=-2.801; P=0.006), radial parapapillary capillaries (R=-3.936; P<0.001) and enhanced-depth imaging of the fovea (R=-2.161; P=0.034). Additionally, FAZ was not significantly correlated with any factors in the current study. Age was negatively correlated with the VFD of the retina (R=-4.234; P<0.001), while the optic tilt ratio (R=-2.291; P=0.025) was negatively correlated with three sectors in the deep layer. Overall, the present results demonstrated that optic disc deformation was negatively correlated with the retinal microvasculature in non-pathological high myopia, particularly in the radial peripapillary capillaries and the deep retinal plexus. Therefore, optic disc deformation may be used to predict the retinal vasculature in high myopia.

The Natural History of Bruch’s Membrane Calcification in Pseudoxanthoma Elasticum

PurposeTo describe the natural history of Bruch’s membrane (BM) calcification in patients with pseudoxanthoma elasticum (PXE).DesignRetrospective cohort study.ParticipantsBoth eyes of 120 PXE patients younger than 50 years, 78 of whom had follow-up imaging after more than 1 year.MethodsAll patients underwent multimodal imaging, including color fundus photography, near-infrared reflectance (NIR) imaging, and late phase indocyanine green angiography (ICGA). We determined the distance from the optic disc to the central and temporal border of peau d’orange on NIR, expressed in horizontal optic disc diameter (ODD). The length of the longest angioid streak was classified into 5 zones.Main Outcome MeasuresAge-specific changes of peau d’orange, angioid streaks, and ICGA hypofluorescence as surrogate markers for the extent of BM calcification.ResultsIn cross-sectional analysis, longer angioid streaks were associated with increasing age (P < 0.001 for trend). The temporal border of peau d’orange showed a weak association with increasing age (β = 0.02; 95% confidence interval [CI], 0.00–0.04), whereas the central border showed a strong association (β = 0.12; 95% CI, 0.09–0.15). Longitudinal analysis revealed a median shift of the central border to the periphery of 0.08 ODD per year (interquartile range [IQR], 0.00–0.17; P < 0.001). This shift was more pronounced in patients younger than 20 years (0.12 ODD per year [IQR, 0.08–0.28]) than in patients older than 40 years (0.07 ODD per year [IQR, –0.05 to 0.15]). The temporal border did not shift during follow-up (P = 0.69). New or growing angioid streaks were detected in 39 of 156 eyes (25%). The hypofluorescent area on ICGA was visible only in the fourth or fifth decade and correlated with longer angioid streaks.ConclusionsIn PXE patients, the speckled BM calcification slowly confluences during life. The location of the temporal border of peau d’orange remains rather constant, whereas the central border shifts to the periphery. This suggests the presence of a predetermined area for BM calcification. A larger ICGA hypofluorescent area correlates with older age and longer angioid streaks, which implies that it depends on the degree of BM calcification.

Association between morphological characteristics of the optic disc and other anatomical features of the fundus in highly myopic eyes

To investigate associated factors with optic disc characteristics in high myopia patients. According to the meta-analysis of pathologic myopia study, patients were divided into groups from categories 1 (C1) to C4. The diameters, tilt ratio, and rotation degree of optic disc, and the diameters of parapapillary atrophy were measured among other morphometric variables. Totally 147 eyes (84 patients) were included. Longer horizontal optic disc diameter was associated with smaller tilt ratio (p < 0.001, unstandardized regression coefficient B: -0.59), greater rotation degree (p < 0.001, B: 0.01), and longer horizontal delta zone diameter (p < 0.001, B: 0.09). Longer vertical optic disc diameter was associated with smaller rotation degree (p < 0.001, B: 0.01), longer vertical delta zone diameter (p < 0.001, B: 0.16), and longer disc-fovea distance (DFD; p < 0.024, B: 0.14). Generally, the horizontal optic disc diameter of C3 and C4 groups was smaller than C1 and C2, while vertical diameter and tilt ratio was greater than in C1 and C2. After setting axial length (AL) as an independent variable, horizontal diameters and tilt ratio still showed significant differences, while vertical diameters did not show significant differences. Axial elongation was associated with an increase of vertical optic disc diameter that was correlated with an reduction of optic disc rotation degree. By contrast, horizontal optic disc diameter elongation was correlated with an reduction of optic disc tilt ratio and an increase of optic disc rotation degree, which was independent of axial elongation.

Long term change of the optic disc and OCT parameters during myopic shift in children with large cup to disc ratio.

PurposeThis observational case series was to determine long term optic disc changes in eyes with large cup to disc ratio (CDR) and compare the changes induced by myopic shift during childhood with normal control eyes.MethodsChildren under 15 years of age who developed myopia with serial optic disc photographs and spectral domain (SD)-optical coherence tomography (OCT) images with a minimal interval of three years were evaluated. Children with average CDR ≥ 0.6 on SD-OCT were classified as having large CDR. The ratios of vertical disc diameter (VDD), horizontal disc diameter (HDD), and maximum peripapillary atrophy (PPA) width (PPW) were measured to quantify morphologic changes of optic discs and SD-OCT parameters, such as peripapillary retinal nerve fiber layer (RNFL) thickness and macular ganglion cell and inner plexiform layer (GCIPL) thickness were measured.ResultsOf the 82 eyes (82 patients) analyzed, 42 eyes had large CDR and 40 eyes were normal controls. The mean age and refractive error at initial examination were not different between groups (P = 0.33, P = 0.76, respectively). The changes in HDD/VDD and PPW/VDD ratios during follow-up showed no significant difference among the groups (P = 0.45, P = 0.62, respectively). No statistical significance was found in changes in RNFL and GCIPL thickness between the two groups (P = 0.74, P = 0.79, respectively).ConclusionsChildren with enlarged CDR showed changes in optic disc morphology and RNFL/GCIPL thickness similar to normal children during myopic shift.

An innovative and simple method, clinically comparable to high-definition optical coherence tomography in quantifying posterior segment lesions in the retina.

Purpose:To introduce a simple and inexpensive method using a fundus contact lens and a reticle, to measure retinal lesions comparing it with values obtained with high-definition optical coherence tomography (HD-OCT). This study considers optic disc as the object for comparison.Methods:Patients underwent routine ophthalmologic examination and their horizontal optic disc diameter was measured, both with the reticle and OCT. For measurement with reticle a simple equation was deduced, x = 0.7y, where x corresponds to the actual image size and y to the reticle scale reading in millimeters.Results:An aggregate of 127 eyes of 75 patients were dilated and examined. The calculated mean diameter according to OCT was 1.639 mm (standard deviation = 0.179) and that assenting to reticle was 1.713 mm (standard deviation = 0.175), with a difference in mean being 0.089 mm.Conclusion:Values obtained by this new method was found to be comparable with the OCT values for retinal measurements, useful for ophthalmologists who cannot afford expensive and sophisticated machines.

Comparison of optic disk features in preterm and term infants

To compare the optic disk features of preterm and term infants. Digital fundus images of preterm infants were compared with those of infants born at term, imaged within 1week of birth. The optic disk horizontal diameter to vertical diameter ratio, the disk-macula to disk-diameter ratio, and the presence or absence of double ring sign was noted. Images of 649 infants (324 preterm and 325 term) were analyzed. Of the preterm infants, 129 (40%) had a double ring sign, compared to 4% in term infants. The double ring was seen more frequently in infants of European descent and was more common with younger gestational age. The mean horizontal to vertical disk diameter in preterm infants on first examination was 0.75±0.063, increasing to 0.80±0.069 at final examination. Term infants had a horizontal to vertical disk diameter ratio of 0.79±0.064. At final examination, the ratio of disk-to-macula distance to the horizontal disk diameter was 3.9 in preterm infants and 3.7 for term infants. In our study population preterm infants often had a double ring sign around the optic disk in the absence of optic nerve hypoplasia. Preterm disks tend to be more vertically oval, which becomes less oval closer to term. The mean disk-to-macula to disk-diameter ratio among normal preterm infants was higher than previously reported.

PARAPAPILLARY GAMMA AND DELTA ZONES IN HIGH MYOPIA.

To examine parapapillary zones gamma and delta in highly myopic eyes. The retrospective observational study included patients attending the Tokyo high myopia clinics. Fundus photographs were morphometrically examined. The study population included 600 eyes (304 individuals) with a mean age of 62.7 ± 14.3 years (range: 13-90 years) and mean axial length of 29.6 ± 2.2 mm (range: 23.2-35.4 mm). In multivariate analysis (regression coefficient r:0.90), larger horizontal gamma zone diameter was correlated with wider delta zone diameter (P < 0.001; standardized regression coefficient beta: 0.81), higher ratio of vertical-to-horizontal disk diameter (P < 0.001; beta: 0.10), shorter fovea-outer gamma zone border distance (P < 0.001; beta: -0.19), longer disk-fovea distance (P < 0.001; beta: 0.18), and higher count of chorioretinal atrophic lesions (P < 0.001; beta: 0.07). Longer horizontal delta zone width was correlated with longer horizontal gamma zone diameter (P < 0.001; beta: 1.00), longer horizontal disk diameter (P < 0.001; beta: 0.15), shorter disk-fovea distance (P < 0.001; beta: -0.19), longer fovea-outer gamma zone border distance (P < 0.001; beta: 0.19), and smaller diameter of the largest chorioretinal lesion (P = 0.03; beta: -0.04). Longer width of both zones together was associated with longer horizontal disk diameter (P < 0.001; beta: 0.31), higher ratio of vertical-to-horizontal disk diameter (P = 0.001; beta: 0.18), longer disk-fovea distance (P < 0.001; beta: 0.19), shorter fovea-outer gamma zone border distance (P < 0.001; beta: -0.18), higher number of chorioretinal lesions (P < 0.001; beta: 0.30), and longer vertical distance between the superior and inferior temporal arterial arcade (P = 0.001; beta: 0.13). Larger gamma and delta zones were correlated with larger optic disk and more marked vertical optic disk rotation, longer disk-fovea distance, higher number of chorioretinal lesions, and longer temporal vascular arcade diameter. Parapapillary gamma and delta zones may develop before chorioretinal lesions develop and enlarge.