Retinal Nerve Fiber Layer Protrusion Associated with Tilted Optic Discs.

SIGNIFICANCE: This study resulted in the identification of an optic nerve head (ONH) feature associated with tilted optic discs, which might potentially contribute to ONH pathologies. Knowledge of such findings will enhance clinical insights and drive future opportunities to understand disease processes related to tilted optic discs. PURPOSE: The aim of this study was to identify novel retinal nerve fiber layer (RNFL) anomalies by evaluating tilted optic discs using optical coherence tomography. An observed retinal nerve fiber protrusion was further investigated for association with other morphological or functional parameters. METHODS: A retrospective review of 400 randomly selected adult patients with ONH examinations was conducted in a referral-only, diagnostic imaging center. After excluding other ONH pathologies, 215 patients were enrolled and evaluated for optic disc tilt and/or torsion. Gross anatomical ONH features, including size and rim or parapapillary region elevation, were assessed with stereoscopic fundus photography. Optical coherence tomography provided detailed morphological information of individual retinal layers. Statistical analysis was applied to identify significant changes between individual patient cohorts. RESULTS: A dome-shaped hyperreflective RNFL bulge, protruding into the neurosensory retina at the optic disc margins, was identified in 17 eyes with tilted optic discs. Available follow-up data were inconclusive regarding natural changes with this ONH feature. This RNFL herniation was significantly correlated with smaller than average optic disc size (P = .005), congenital disc tilt (P < .0001), and areas of rim or parapapillary elevation (P < .0001). CONCLUSIONS: This study reports an RNFL protrusion associated with tilted optic discs, which has not previously been assessed as an independent ONH structure. The feature is predominantly related to congenital crowded, small optic discs and variable between patients. This study is an important first step to elucidate diagnostic capabilities of tilted disc morphological changes and understanding associated functional deficits.

Influence of education and diagnostic modes on glaucoma assessment by optometrists.

PURPOSE: To evaluate the influence of different clinical examination techniques, including optic nerve head (ONH) photography, visual field tests, and adjunct imaging on the diagnosis of glaucoma by Australian and New Zealand optometrists. The effect of a short-term, didactic teaching module on these is also explored. METHODS: Clinical data of 30 patients previously seen at the Centre for Eye Health was collected and compiled into glaucoma diagnostic assessment modules. Each of six modules contained different combinations of clinical examination results and required a classification of the cases as normal, suspicious or glaucoma. A cohort of 54 Australian and New Zealand optometrists were recruited for the study and allocated into two cohorts. The intervention group completed a glaucoma training course prior to the assessment while the control group completed the assessment without additional training. Diagnostic accuracy was compared between modules and optometrist groups. RESULTS: High false negative rates were observed with ONH photography, which were drastically reduced with the addition of visual field, albeit at the cost of increased false positive rates. Addition of adjunct imaging techniques partially compensated for the increase in the false positive rate from the visual field, but had limited effect on false negative rate. Educational intervention resulted in larger improvement in the diagnostic ability when multiple imaging modalities were provided. CONCLUSION: The study highlighted the importance of combining both structural and functional assessments in glaucoma. Current imaging technology demonstrated limited usefulness for event diagnosis due to the persistent difficulties of defining structural and functional loss in glaucoma, thus highlighting the need for new glaucoma assessment techniques. Short-term didactic teaching programs may only result in limited improvement of glaucoma diagnostic ability in optometrists, and hence, it may need to be combined with long-term and/or non-didactic training components to obtain a greater effect.

Clinical utility of irx3 in keratoconus.

CLINICAL RELEVANCE: Diagnosis and monitoring of keratoconus is increasingly being conducted with the aid of imaging equipment such as corneal aberrometry. There is a need to also know the confidence with which ocular aberration measurements can be made. BACKGROUND: To assess the repeatability of lower- and higher-order aberration measurements in patients with keratoconus using the irx3 wavefront aberrometer (Imagine Eyes, Orsay, France) and evaluate correlations with corneal curvature. METHODS: The irx3 wavefront aberrometer was used to measure bilateral lower- and higher-order ocular aberrations on 33 participants with keratoconus. Three measurements were taken from each eye to determine the repeatability of lower-order aberrations (quantified as sphere and cylinder in dioptres) and higher-order aberration co-efficients (up to eighth order in micrometres), coma, trefoil and total higher-order aberration root mean square (in micrometres). Corneal curvature was measured using the Pentacam HR system (OCULUS, Wetzlar, Germany). RESULTS: Repeat measurements for lower-order aberrations resulted in larger co-efficients of repeatability than higher-order aberrations. Similarly, larger co-efficients of repeatability between repeated measures across all Zernike co-efficients were observed in eyes with severe keratoconus (that is, corneal curvature > 52-D) compared to eyes with flatter corneas. The difference between repeated measures tended to be significant for the lower-order aberrations regardless of corneal curvature. The highest correlations with corneal curvature for right and left eyes respectively, were identified for total higher-order aberration root mean square (r = 0.92, p < 0.001 and r = 0.91, p < 0.001), followed closely by coma (r = -0.93, p < 0.001 and r = -0.86, p < 0.001) and the Z (3, -1) co-efficient (r = -0.92, p < 0.001 and r = -0.86, p < 0.001 for right and left eyes, respectively). CONCLUSIONS: Lower-order aberrations tended to be less repeatable, indicating that instrument variability must be considered when monitoring progression. Total higher-order aberration root mean square and third-order aberrations, in particular the vertical coma Z (3, -1) co-efficient, demonstrated a stronger correlation with corneal curvature than the lower-order aberrations.

Review of referrals reveal the impact of referral content on the triage and management of ophthalmology wait lists.

OBJECTIVES: Many chronic eye conditions are managed within public hospital ophthalmology clinics resulting in encumbered wait lists. Integrated care schemes can increase system capacity. In order to direct implementation of a public hospital-based integrated eye care model, this study aims to evaluate the quality of referrals for new patients through information content, assess triage decisions of newly referred patients and evaluate the consistency of referral content for new patients referred multiple times. DESIGN: A retrospective and prospective review of all referral forms for new patients referred to a public hospital ophthalmology clinic between January 2016 and September 2017, and September 2017 and August 2018, respectively. SETTING: A referral-only public hospital ophthalmology clinic in metropolitan Sydney, Australia. PARTICIPANTS: 418 new patients on existing non-urgent wait lists waiting to be allocated an initial appointment, and 528 patients who were newly referred. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was the information content of referrals for new patients. The secondary outcomes were triage outcomes for new incoming referrals, and the number of new patients with multiple referrals. RESULTS: Of the wait-listed referrals, 0.2% were complete in referral content compared with 9.8% of new incoming referrals (p<0.001). Of new incoming referrals, 56.7% were triaged to a non-urgent clinic. Multiple referrals were received for 49 patients, with no change in the amount of referral content. CONCLUSIONS: Most referrals were incomplete in content, leading to triage based on limited clinical information. Some new patients were referred multiple times with their second referral containing a similar amount of content as their first. Lengthy wait lists could be prevented by improving administrative processes and communication between the referral centre and referrers. The future implementation of an integrated eye care model at the study setting could sustainably cut wait lists for patients with chronic eye conditions.

Multimodal imaging characteristics of congenital grouped hyper- and hypo-pigmented fundus lesions.

BACKGROUND: The imaging characteristics of congenital grouped pigmentation of the retinal pigment epithelium (CGP-RPE) and its non-pigmented variant - grouped congenital albinotic retinal pigment epithelial spots (GCARPES) are poorly defined in the literature. Our case series reports their multimodal imaging characteristics across a spectrum of presentations. METHODS: A retrospective review of patient records was conducted on patients seen at the Centre for Eye Health between January and December 2016. The multimodal imaging findings across four cases is described using optical coherence tomography (OCT), infrared imaging, ultra-widefield imaging, fundus photography and fundus autofluorescence (FAF). RESULTS: Case 1 is a 55-year-old female with a bilateral presentation of CGP-RPE showing typical features. Case 2 is a 28-year-old male with a classical presentation of GCARPES in the left eye. Case 3 is a 33-year-old female with unilateral CGP-RPE and an atypical solitary congenital hypertrophy of the retinal pigment epithelium (CHRPE) in the same eye. Case 4 is a unilateral presentation in an 11-year-old female with unusual characteristics. Ocular imaging characteristics of CGP-RPE lesions varied between patients: OCT showed visible RPE changes in cases 3 and 4 but not case 1. The pattern of FAF and infrared imaging also varied with most lesions displaying a pattern of hypo-autofluorescence, but some central lesions in case 3 exhibited hyper-autofluorescence. All lesions were visible with fundus photography. CONCLUSION: FAF can be helpful in alerting clinicians to the presence of lesions that may be difficult to visualise funduscopically and OCT can be helpful in differentiating between CGP-RPE and its variants from more sinister ocular conditions. All in all, these findings highlight the variable manifestation of CGP-RPE and its variants on multimodal imaging; the diagnosis of CGP-RPE and its variants should remain based on its characteristic funduscopic appearance.

Glaucoma Community Care: Does Ongoing Shared Care Work?

PURPOSE: We assessed a novel, public, vertical integrated care model for glaucoma management in the community. METHODS: This study was a retrospective, longitudinal study of 266 patients diagnosed or suspected of glaucoma. Patients were stratified to either ongoing ophthalmology-led (n = 81) or optometry-led shared care (n = 185). Demographics and clinical characteristics, including the re-referral rate and timeliness of follow up were analysed. RESULTS: Just under half (565/1224, 46%) of all follow up consultations over the total study period of 45 months were seen in optometry-led care, with a re-referral rate to ophthalmology of 21%. Treated patients showed a median intraocular pressure reduction of 20% and a median time delay of just two days between the actual and recommended review period. CONCLUSIONS: Shared care provides an effective option for managing the ongoing care burden in chronic stable glaucoma cases at low risk of vision loss.

Impact of referral refinement on management of glaucoma suspects in Australia.

BACKGROUND: In ageing populations, the prevalence of chronic diseases such as glaucoma is projected to increase, placing additional demands on limited health-care resources. In the UK, the demand for secondary care in hospital eye clinics was inflated by high rates of false positive glaucoma referrals. Collaborative care models incorporating referral refinement, whereby glaucoma suspect referrals are triaged by suitably trained optometrists through further testing, can potentially reduce false positive referrals. This study examined the impact of a referral refinement model on the accuracy of glaucoma referrals in Australia. METHODS: Optometrist-initiated glaucoma suspect referrals to the Glaucoma Management Clinic (Sydney, Australia) were prospectively recruited. Glaucoma suspect referrals arising from two pathways were eligible for inclusion, either directly from a community optometrist (standard care) or following comprehensive assessment at the Centre for Eye Health (referral refinement). Main outcome measures were the positive predictive value and false positive rate of referrals. The impact of referral letter content on management outcomes was also investigated. RESULTS: Of 464 referrals received between March 2015 and June 2018, 252 were for treatment of naïve glaucoma suspects and eligible for inclusion. Following ophthalmological assessment, 45.6 per cent (n = 115/252) were prescribed treatment for open angle glaucoma or ocular hypertension. Positive predictive value of community optometry referrals was 33.8 per cent (n = 25/74) and 50.6 per cent (n = 90/178) following referral refinement. The first visit discharge (false positive) rate was 26 per cent (n = 19/74) for community referrals compared to four per cent (n = 8/178) with referral refinement. Positive predictive value increased with the number of abnormal clinical examination findings associated with referral (χ2 test, p < 0.0001). The number of abnormal findings reported in referrals was significantly higher with referral refinement compared to without (n = 1.9 versus 1.5, t-test, p < 0.0001). CONCLUSION: Referral refinement can improve the diagnostic accuracy of optometry-initiated referrals for glaucoma suspects in Australia, thereby decreasing unnecessary referrals to hospital and other secondary clinics.

Evaluation of a hospital-based integrated model of eye care for diabetic retinopathy assessment: a multimethod study.

OBJECTIVES: Diabetic eye disease is a leading cause of blindness but can be mitigated by regular eye assessment. A framework of issues, developed from the literature of barriers to eye assessment, was used to structure an examination of perceptions of a new model of care for diabetic retinopathy from the perspective of staff using the model, and health professionals referring patients to the new service. DESIGN: Multimethod: interviews and focus groups, and a separate survey. SETTING: A new clinic based on an integrated model of care was established at a hospital in outer metropolitan Sydney, Australia in 2017. Funded jointly by Centre for Eye Health (CFEH) and the hospital, the clinic was equipped and staffed by optometrists who work alongside the ophthalmologists in the existing hospital eye clinic. PARTICIPANTS: Five (of seven) hospital staff working in the clinic (ophthalmologists and administrative officers) or referring to it from other departments (endocrinologists); nine optometrists from CFEH who developed or worked in the clinic; 10 community-based optometrists as potential referrers. RESULTS: The new clinic was considered to have addressed known barriers to eye assessment, including access, assistance for patients unable/unwilling to organise eye checks and efficient management of human resources. The clinic optimised known drivers of this model of care: providing clear scope of practice and protocols for shared care between optometrists and ophthalmologists, good communication between referrers and eye professionals and a collegial approach promoting interprofessional trust. Remaining areas of concern were few referrals from general practitioners, fewer referrals from hospital endocrinologists than expected and issues with stretched administrative capacity. There were also perceived mismatches between the priorities of hospital management and aims of the clinic. CONCLUSIONS: The new model was considered to have addressed many of the barriers to assessment. While there remain issues with the model, there were also unexpected benefits.

Interocular asymmetry of the superonasal retinal nerve fibre layer thickness and blood vessel diameter in healthy subjects.

BACKGROUND: Optical coherence tomography is commonly used to measure the retinal nerve fibre layer thickness in both normal and diseased eyes; however, variation among normal eyes is common and may limit the usefulness of the results. The aim of this study was to explore the interocular asymmetries in retinal nerve fibre layer thickness in a group of normal eyes and to investigate the influence of blood vessel diameter on local retinal nerve fibre layer thickness. METHODS: In this prospective study, retinal nerve fibre layer thickness and blood vessel diameter across 100 healthy participants were measured using two optical coherence tomography instruments. Individuals were categorised into two groups based on the presence or absence of interocular retinal nerve fibre layer thickness asymmetry beyond the 75th percentile of all participants. RESULTS: The superonasal sectoral retinal nerve fibre layer thickness was significantly greater in the left eye compared to the right, across all three sectors. Mean blood vessel diameter showed a corresponding difference in thickness at one of the superonasal sectors. Linear regression showed a positive and moderate correlation between blood vessel diameter and focal retinal nerve fibre layer thickness. This trend persisted across both arteries and veins, but veins showed larger variability between left and right eye in participants with marked superonasal retinal nerve fibre layer asymmetry. CONCLUSION: Retinal nerve fibre layer thickness and blood vessel diameter vary significantly between eyes even in healthy individuals. These asymmetries in a normal population should be taken into consideration when interpreting the retinal nerve fibre layer thickness measurements from optical coherence tomography to assist in distinguishing normal variations from disease.

The impact of optic nerve and related characteristics on disc area measurements derived from different imaging techniques.

PURPOSE: Optic nerve head (ONH) assessment and its interpretation in healthy patients and those with glaucoma remains a pivotal topic specifically considering rapid advancements in imaging technologies. We undertook a large-scale, mixed cohort, comparative study to assess the correlation of optic disc measurements between different imaging modalities and investigated the impact of patient and disc associated parameters. METHODS: ONH sizes were obtained from one randomly selected eye of each of 209 patients using stereophotography, confocal scanning laser ophthalmoscopy and two different optical coherence tomographers (OCT). Patient related data, glaucoma status and optic disc variables, specifically oblique insertion, torsion, presence of beta PPA and spherical equivalent were recorded. Measurements between imaging modalities were analysed using Pearson correlation, linear regression analysis and Blend-Altman plots. Individual variables were compared applying multivariate regression analysis, ANOVA and chi square statistics was used to determine correlations between patient and clinical characteristics. RESULTS: Absolute measurements significantly differed between imaging modalities generally producing smaller measurements for OCT derived measurements of Bruch's membrane opening (BMO). Pairwise correlations between imaging modalities were between 0.83 and 0.93 for discs without myopia, oblique insertion, or beta PPA. These features impacted on measurements for individual modalities and consequently contributed to inconsistencies and variability. CONCLUSION: In comparison to planimetry, OCT derived BMO measurements are more variable in the presence of oblique insertion, beta PPA or magnification errors due to myopia. Impact of these factors, however, differs between instruments and needs to be considered to accurately interpret optic disc features in particular within the context of glaucoma diagnosis.

Developing prognostic biomarkers in intermediate age-related macular degeneration: their clinical use in predicting progression.

Age-related macular degeneration is a common, complex and blinding eye disease. When early and intermediate levels of severity are detected in one or both eyes, there is a wide-ranging 0.4 to 53 per cent risk of progression to advanced disease in five years. In order to maximise visual outcomes for their patients, practising eye-care professionals must be able to stratify patients according to their risk of progression, intervene (for example by recommending smoking cessation or nutritional supplements and Amsler grid self-monitoring in intermediate disease) and monitor accordingly. With the aid of ocular imaging, a range of under-recognised yet meaningful risk factors have been identified. The purpose of this review is to assist the eye-care practitioner in stratifying the risk of progression in intermediate age-related macular degeneration using the range of established and emerging precursory signs that herald loss of vision.

The value of visual field testing in the era of advanced imaging: clinical and psychophysical perspectives.

White-on-white standard automated perimetry (SAP) is widely used in clinical and research settings for assessment of contrast sensitivity using incremental light stimuli across the visual field. It is one of the main functional measures of the effect of disease upon the visual system. SAP has evolved over the last 40 years to become an indispensable tool for comprehensive assessment of visual function. In modern clinical practice, a range of objective measurements of ocular structure, such as optical coherence tomography, have also become invaluable additions to the arsenal of the ophthalmic examination. Although structure-function correlation is a highly desirable determinant of an unambiguous clinical picture for a patient, in practice, clinicians are often faced with discordance of structural and functional results, which presents them with a challenge. The construction principles behind the development of SAP are used to discuss the interpretation of visual fields, as well as the problem of structure-function discordance. Through illustrative clinical examples, we provide useful insights to assist clinicians in combining a range of clinical results obtained from SAP and from advanced imaging techniques into a coherent picture that can help direct clinical management.

A survey of visual impairment and blindness in children attending seven schools for the blind in Myanmar.

PURPOSE: To determine the causes of visual impairment and blindness amongst children in schools for the blind in Myanmar; to identify the avoidable causes of visual impairment and blindness; and to provide spectacles, low vision aids, orientation and mobility training and ophthalmic treatment where indicated. METHODS: Two hundred and eight children under 16 years of age from all 7 schools for the blind in Myanmar were examined and the data entered into the World Health Organization Prevention of Blindness Examination Record for Childhood Blindness (WHO/PBL ERCB). RESULTS: One hundred and ninety nine children (95.7%) were blind (BL = Visual Acuity [VA] < 3/60 in the better eye) and 3 had severe visual impairment (SVI = VA < 6/60 to 3/60 in the better eye). Most children had corneal abnormalities as the major anatomical site of SVI/BL (100, 49.5%), however the cause of SVI/BL was unknown in the majority (88, 43.6%). Measles keratitis was the commonest identifiable cause (17.4%) and 88 children had avoidable causes of SVI/BL (43.6%). Nearly 16% of children required an optical device and 24.2% required medical attention, with a potential for visual improvement through intervention in 15.8%. CONCLUSION: Nearly half of the children in schools for the blind in Myanmar had potentially avoidable causes of SVI/BL. With measles being both the commonest identifiable and commonest avoidable cause, the data supports the need for a measles immunization campaign. There is also a need for a dedicated pediatric eye care center with regular ophthalmology visits to the schools, and improved optometric, low vision and orientation and mobility services in Myanmar.