Measurement of Normal Optic Nerve Head Parameters (2023)

In this study, we did not compare either measures derived from funduscopy or from digital fundus photography with handheld SD OCT results. Samarawickrama et al40 compared digital planimetry results with table-mounted OCT results in 333 children 6.4 to 6.5 years of age and found that “OCT produced consistently smaller linear and area measures than digital planimetry,” also noting that “digital planimetry may be more sensitive than OCT in detecting small, physiologically normal optic cups and hence small cup/disc ratios.” However, Dai et al41 observed that 2-dimensional measurements of the optic disc with fundus imaging can lead to underestimates of horizontal and vertical disc measurements.

To determine feasibility of optic nerve head (ONH) imaging and to characterize ONH development in full-term infants without sedation using handheld spectral-domain optical coherence tomography (SD OCT).

Prospective cross-sectional study.

Three hundred fifty-two children aged between 1 day and 13 years.

All participants were imaged using handheld SD OCT without sedation during a single scan session. The percentage of successful scans was calculated. Interexaminer reproducibility and differences between right and left eyes were assessed using intraclass correlation coefficients (ICCs). Images were analyzed using ImageJ software. The developmental trajectories over time for ONH parameters were calculated using fractional polynomial modelling.

Disc and cup diameter (expressed as distance in micrometers and visual angle in degrees), cup depth, Bruch's membrane opening–minimum rim width (BMO-MRW), retinal thickness, and retinal nerve fiber layer (RNFL; 1700 μm and 6° from the disc center).

On average, 70% of participants were imaged successfully. Interexaminer reliability was excellent (ICC, >0.89) for diametric and retinal thickness parameters. Right and left eyes were similar for diametric measurements (ICC, >0.79), but more variable for nasal BMO-MRW, RNFL, and retinal thickness. The mean disc and cup diameter increase by 30% and 40%, respectively, between birth and 13 years of age when expressed as a distance measure, but remained constant (at 5°–5.5° and 2°, respectively) when expressed as a visual angle with reference to the eye nodal point. The peripapillary temporal RNFL demonstrated a marked initial decrease of nearly 35% between birth and approximately 18 months of age. This was followed by a slow increase up to 12years of age when measured at 1700 μm from the disc center, although there was little change when measured at 6° from the disc center.

We demonstrated feasibility of handheld SD OCT imaging of the ONH in full-term infants and children without anaesthesia or sedation. This is the first invivo handheld SD OCT study to describe the development of ONH parameters during the critical early years of visual maturation. Our results provide a normative database for use in routine practice and further studies of ONH pathologic features.

However, these methods do not account for peripheral distortion of the UWF images. In addition, the sizes of the landmarks vary from one person to another; thus, such conversion strategies are not accurate.17 The stereographic projection used in this study provides a conformal 2-dimensional image-preserving shape mapped by ray tracing all relevant pixels from a 3-dimensional model.12

To establish the extent of the peripheral retinal vasculature in normal eyes using ultra-widefield (UWF) fluorescein angiography.

Prospective, observational study.

Fifty-nine eyes of 31 normal subjects, stratified by age, with no evidence of ocular disease in either eye by history and ophthalmoscopic examination.

Ultra-widefield fluorescein angiographic images were captured centrally and with peripheral steering using the Optos 200Tx (Optos, Dunfermline, United Kingdom). Images obtained at different gaze angles were montaged and corrected for peripheral distortion using a stereographic projection method to provide a single image for grading of the peripheral edge of the visible vasculature. The border of the vascularized retina was expressed as a radial surface distance from the center of the optic disc. The vascularized area was calculated based on this mean peripheral border position for each quadrant.

Mean distance (mm) from the center of optic disc to the peripheral vascular border.

In normal eyes, the mean radial surface distance from the center of the optic disc to the peripheral edge of the visible vasculature was 20.3±1.4 mm and the mean area of normal perfused retina was 977.0 mm². There was no significant difference between right and left eyes or between male and female participants. However, the distance to the periphery differed depending on the quadrant, with temporal (22.5±0.9 mm) beinglarger than inferior (20.4±1.7 mm) being larger than superior (19.2±1.5 mm) being larger than nasal (17.4±0.9 mm; P < 0.001) for all interquadrant comparisons. Interestingly, the distances to the perfused vascular border were significantly shorter in older individuals (≥60 years) than in younger subjects.

Ultra-widefield fluorescein angiography is an important tool for studying the extent of peripheral retinal vasculature. With the increasing use of UWF imaging to evaluate and manage patients with retinal vascular disease, the normative data from this study may provide a useful reference when assessing the pathologic significance of findings in the setting of disease.

Our recently published photoplethysmographic technique allows us to accurately determine the location and amplitude of venous pulsation at varying locations surrounding the human optic nerve (Morgan et al., 2014, 2015a). In this study, we correlate venous pulsation with SD-OCT anatomical parameters to quantitatively and qualitatively study structural characteristics surrounding sites of venous pulsation (Samarawickrama et al., 2012). This study was approved by the Human Research Ethics Committee of The University of Western Australia.

To evaluate visual outcomes in patients treated for lens subluxation. Secondary objectives are to report best corrected visual acuity (BCVA) in LogMAR and compare the outcomes of patients managed conservatively with those treated surgically.

Retrospective comparison of BCVA in patients under the age of 50 years old with lens subluxation, managed conservatively or surgically.

A total of 49 eyes of 28 patients were included. Demographic characteristics were similar in both groups. Twenty eyes were treated surgically (40.8%) compared to 29 with medical treatment (59.2%). Marfan syndrome (79.6%) was diagnosed in 39 eyes. LogMAR BCVA post intervention was 0.35±0.31 for medical treatment and 0.39±0.32 for the surgical group, with no significant differences (p=0.63). Improvements in LogMAR lines were 2.7±4.2 and 4.11±4.2 (p=0.35), respectively. Two eyes in the surgery group developed ocular hypertension (0.04%), none with retinal detachment.

The final BCVA showed no significant differences in this group of patients. BCVA depends on the visual potential of the rehabilitated eye rather than a specific type of intervention.

Evaluar resultados visuales en pacientes tratados por subluxación del cristalino. Los objetivos secundarios son reportar la agudeza mejor corregida (AVMC) en LogMAR y comparar los resultados de los pacientes manejados de manera conservadora con aquellos manejados quirúrgicamente.

Estudio retrospectivo comparativo de AVMC en pacientes menores de 50 años con subluxación de cristalino, manejados de manera conservadora con lentes o tratados quirúrgicamente.

49 ojos de 28 pacientes fueron incluidos. Las características demográficas fueron similares en ambos grupos. 20 ojos fueron tratados quirúrgicamente (40,8%) versus 29 con tratamiento médico (59,2%). 39 ojos con diagnóstico de síndrome de Marfán (79,6%). La AVMC LogMAR post intervención de 0,35±0,31 para el tratamiento médico y 0,39±0,32 para el grupo de manejo quirúrgico, sin encontrarse diferencias significativas (p=0,63). Las mejorías en líneas LogMAR fueron respectivamente 2.7±4.2 y 4.11±4.2 (p=0,35). Dos ojos del grupo cirugía evolucionaron con hipertensión ocular (0,04%), ninguno con DR.

La AVMC final no presentó diferencias significativas en este grupo de pacientes, dependiendo del potencial visual del ojo rehabilitado más que de un tipo específico de intervención.

To investigate optic disc margin anatomic features in myopic eyes with open-angle glaucoma (OAG) using spectral-domain (SD) OCT.

Cross-sectional study.

Two hundred four eyes of 102 participants with OAG and 106 eyes of 53 participants without glaucoma with axial length of 24 mm or more.

Radial SD OCT B-scans centered on the optic discs were acquired in each eye, and the SD OCT data were colocalized with the optic disc stereophotographs. Optic disc margin anatomic features were evaluated as (1) SD OCT structure coinciding with the disc margin identified in the stereophotograph, (2) border tissue configuration, and (3) presence of Bruch’s membrane overhang, and their frequency was computed in each clock-hour position. Further, paired eyes of myopic participants with OAG were divided into eyes with better or worse visual field defect (VFD), according to the mean deviation of the Humphrey visual field test, and associated factors were compared.

Spectral-domain OCT structures coinciding with the visible optic disc margin in stereophotographs.

In myopic eyes with OAG, mean axial length was 25.96±1.07 mm and mean deviation was –8.87±7.78 dB. In approximately 90% of the participants, anterior scleral opening (ASO) coincided with the temporal disc margin and Bruch’s membrane opening (BMO) with the nasal disc margin. Border tissue configuration was externally oblique in the temporal region and internally oblique in the nasal region of the optic disc. Bruch’s membrane overhang was observed in a relatively small percentage of eyes. The same pattern of disc margin anatomic features was observed in the myopic eyes without glaucoma. The myopic optic disc was shaped by the temporal shifting of the BMO from the ASO, and the extent of shifting was expressed as the width of γ zone parapapillary atrophy (PPA). The greater γ zone PPA width was associated significantly with the worse VFD between paired eyes.

The myopic eyes with OAG exhibited characteristic optic disc margin anatomic features that was considered to be derived from myopic deformation of the eye. The greater γ zone PPA width may increase susceptibility to the glaucomatous stress.

To establish the optimum grading increment which ensured parity between practitioners while maximising clinical precision.

Second year optometry students (n = 127, 19.5 ± 1.4 years, 55 % female) and qualified eye care practitioners (n = 61, 40.2 ± 14.8 years, 52 % female) had 30 s to grade each of bulbar, limbal and palpebral hyperaemia of the upper lid of 4 patients imaged live with a digital slit lamp under 16× magnification, diffuse illumination, with the image projected on a screen. The patients were presented in a randomised sequence 3 times in succession, during which the graders used the Efron printed grading scale once to the nearest 0.1 increment, once to nearest 0.5 increment and once to the nearest integer grade in a randomised order. Graders were masked to their previous responses.

For most grading conditions less than 20 % of clinicians showed a ≤0.1 difference in grade from the mean. In contrast, more than 50 % of the student graders and 40 % of experienced graders showed a difference in grade from the mean within 0.5 for all conditions under measurement. Student precision in grading was better with both 0.1 and 0.5 grading increments than grading to the nearest unit, except for limbal hyperaemia where they performed more accurately with 0.5 unit increment grading. Limbal grading precision was not affected by grading step increment for experienced practitioners, but 0.1 and 0.5 grading increments were both better than the 1.0 grading increment for bulbar hyperaemia and the 0.1 grading increment was better than the 0.5 grading increment and both were better than the 1.0 grading increment for palpebral hyperaemia.

Although narrower interval scales maximise the ability to detect smaller clinical changes, the grading increment should not exceed one standard deviation of the discrepancy between measurements. Therefore, 0.5 grading increments are recommended for subjective anterior eye physiology grading (limbal, bulbar and palpebral redness).

A review was performed on all patients with Stickler syndrome that had been treated in our Center since it was diagnosed, in order to evaluate the risk of suffering a retinal detachment (RD).

A total of 14 patients, diagnosed by clinical criteria, were included. The following variables were evaluated: age, gender, ocular background, follow-up, initial and final visual acuity (VA), optical prescription, prophylactic treatment, surgery and techniques performed. The risk age to suffer a RD, as well as cataracts, was determined by using the Kaplan–Meier survival curve analysis.

From a total of 5 men and 9 women, the median initial VA was 0.35, which was the same as the final VA. The median optical prescription was −9.5 D myopia. The median of follow-up was 7 years. Ocular background was 4 RD cases and 2 Lasik surgeries. The operations performed were 8 RD, 12 cataract, 2 glaucoma, 2 macular hole, and one endotropia. The median age of RD was 20 years and cataract 34 years. As regards surgical tecnique, 4 scleral buckle cases, and 4 scleral buckle+pars plana vitrectomy cases were formed. The prophylactic treatments performed were: one scleral buckle case, 4 endolaser photocoagulation, and one cryotherapy. Two of which presented with RD.

In the series presented, retinal detachment in Stickler syndrome mainly occurs in the second decade of life, with cataracts mainly developing in the fourth decade.

Revisión de todos los pacientes con síndrome de Stickler que se han tratado en nuestro centro desde su descripción, para valorar el riesgo de padecer desprendimiento de la retina (DR).

Un total de 14 pacientes, diagnosticados por criterios clínicos, en los que hemos valorado las siguientes variables: sexo, edad, antecedentes oculares, seguimiento, agudeza visual (AV) inicial y final, refracción, tratamiento profiláctico, cirugías y la técnica empleada. Mediante el análisis de curva de supervivencia de Kaplan-Meier hemos determinado la edad riesgo de padecer DR así como cataratas.

En total fueron 5 hombres y 9 mujeres. La AV mediana inicial fue de 0,35, igual que la AV final. Refracción mediana de −9,5 dioptrías de miopía. La mediana de seguimiento de 7 años. Los antecedentes oculares fueron 4 DR y 2 Lasik. Las cirugías que realizamos han sido 8 DR, 12 cataratas, 2 glaucomas, 2 agujeros maculares y una endotropía. La mediana de años en el que sucedió el DR fue de 20 y las cataratas a los 34. La técnica quirúrgica utilizada en 4 casos ha sido el cerclaje y en los otros 4 restantes cerclaje con vitrectomía vía pars plana. Un total de 6 ojos han sido tratados profilácticamente: uno con cerclaje, 4 con fotocoagulación láser y otro con criocoagulación; de estos, 2 han presentado DR.

En nuestra serie, el DR en esta dolencia se desarrolla mayoritariamente en la segunda década de la vida. Las cataratas, fundamentalmente en la cuarta década.