Non-contact ultra-widefield imaging of retinopathy of prematurity using the Optos dual wavelength scanning laser ophthalmoscope

Clinical and Molecular Characterization of AIPL1-Associated Leber Congenital Amaurosis/Early-Onset Severe Retinal Dystrophy

PURPOSE

This study aimed to characterize the clinical features, genetic findings, and genotype-phenotype correlations of patients with Leber congenital amaurosis (LCA) or early-onset severe retinal dystrophy (EOSRD) harboring biallelic AIPL1 pathogenic variants.

DESIGN

Retrospective case series.

METHODS

This study consecutively enrolled 51 patients from 47 families with a clinical diagnosis of LCA/EOSRD harboring disease-causing variants in the AIPL1 gene, from October 2021 to September 2023. Molecular genetic findings, medical history, and ophthalmic evaluation including visual acuity (VA), multimodal retinal imaging, and electrophysiologic assessment were reviewed.

RESULTS

Of the 51 patients (32 with LCA and 19 with EOSRD), 27 (53%) were females, and age at last review ranged from 0.5 to 58.4 years. We identified 28 disease-causing AIPL1 variants, with 18 being novel. In patients with EOSRD, the mean (range) VA was 1.3 (0.7-2.7) logMAR and 1.3 (0.5-2.3) logMAR for right and left eyes respectively, with an average annual decline of 0.03 logMAR (R2 = 0.7547, P < .01). For patients with LCA, the VA ranged from light perception to counting fingers. Optical coherence tomography imaging demonstrated preservation of foveal ellipsoid zone in the 5 youngest EOSRD patients and 9 LCA children. Electroretinography showed severe cone-rod patterns in 78.6% (11/14) of patients with EOSRD, while classical extinguished pattern was documented in all patients with LCA available for the examination. The most common mutation was the nonsense variants of c.421C>T, with an allele frequency of 53.9%. All patients with EOSRD carried at least one missense mutation, of whom 13 identified with c.152A>G and 5 with c.572T>C. Twenty-six patients with LCA harbored two null AIPL1 variants, while 18 were homozygous for c.421C>T and 6 were heterozygous for c.421C>T with another loss-of-function variant.

CONCLUSIONS

This study reveals distinct clinical features and variation spectrum between AIPL1-associated LCA and EOSRD. Patients harboring at least one nonnull mutation, especially c.152A>G and c.572T>C, were significantly more likely to have a milder EOSRD phenotype than those with two null mutations. Residual foveal outer retinal structure observed in the youngest proportion of patients suggests an early window for gene augmentation therapy.

Factors at the initial visit associated with poor visual outcomes in patients with acute retinal necrosis

BACKGROUND/OBJECTIVE

Acute retinal necrosis (ARN) is a vision-threatening disease caused by herpesvirus infection. This study aimed to investigate the visual prognostic factors that could be determined at the initial visit.

SUBJECTS AND METHODS

This retrospective study included 34 patients with ARN. Logistic regression analysis was employed to evaluate the associations between poor final visual outcomes and various factors, including poor initial visual acuity, presence of retinal detachment at the initial visit, posterior extension of necrotizing retinitis, and circumferential extension of necrotizing retinitis. Posterior extension was evaluated with three zonings, from the periphery (zone 3), mid-periphery (zone 2), and macula (zone 1). Circumferential extension was evaluated according to the degree of necrotizing retinitis lesions using ultra-wide fundus imaging.

RESULTS

The mean logarithm of the minimum angle of resolution was 0.63 ± 0.68 at the initial visit and 0.83 ± 0.65 at 12 months after the initial visit. Seven patients had a retinal detachment. The distribution of posterior extension at the initial visit was 5 in zone 1, 20 in zone 2, and 9 in zone 3. The average of necrotizing retinitis lesion angle was 249 ± 115°. The logistic regression analysis revealed that participants with wide angles of necrotizing retinitis were associated with final poor vision, with an odds ratio of 1.28 per 30° increase (95%CI: 1.00-1.65, p = 0.03).

CONCLUSIONS

Assessment of the widespread circumferential extension of white necrotizing retinal lesions at the initial visit is a crucial risk factor for the visual prognosis in ARN.

Color fundus imaging in retinopathy of prematurity screening: Present and future

Advent of pediatric handheld fundus cameras like RetCam, 3netra Forus, and Phoenix ICON pediatric retinal camera has aided in effective screening of retinopathy of prematurity (ROP), especially in countries with limited number of trained specialists. Recent advent of various smartphone-based cameras has made pediatric fundus photography furthermore affordable and portable. Future advances like ultra-wide field fundus cameras, trans-pars-planar illumination pediatric fundus camera, artificial intelligence, deep learning algorithm, and handheld SS-OCTA can help in more accurate imaging and documentation. This article summarizes the features of existing and upcoming imaging modalities in detail, including their features, advantages, challenges, and effectiveness, which can help in implementation of telescreening as a standard screening protocol for ROP across developing as well as developed countries.

Optical Coherence Tomography and Optical Coherence Tomography Angiography in Pediatric Retinal Diseases

Indirect ophthalmoscopy and handheld retinal imaging are the most common and traditional modalities for the evaluation and documentation of the pediatric fundus, especially for pre-verbal children. Optical coherence tomography (OCT) allows for in vivo visualization that resembles histology, and optical coherence tomography angiography (OCTA) allows for non-invasive depth-resolved imaging of the retinal vasculature. Both OCT and OCTA were extensively used and studied in adults, but not in children. The advent of prototype handheld OCT and OCTA have allowed for detailed imaging in younger infants and even neonates in the neonatal care intensive unit with retinopathy of prematurity (ROP). In this review, we discuss the use of OCTA and OCTA in various pediatric retinal diseases, including ROP, familial exudative vitreoretinopathy (FEVR), Coats disease and other less common diseases. For example, handheld portable OCT was shown to detect subclinical macular edema and incomplete foveal development in ROP, as well as subretinal exudation and fibrosis in Coats disease. Some challenges in the pediatric age group include the lack of a normative database and the difficulty in image registration for longitudinal comparison. We believe that technological improvements in the use of OCT and OCTA will improve our understanding and care of pediatric retina patients in the future.

Novel techniques for wide-field retinal photography in neonates and infants

Wide-field fundus photography can assist with diagnosis of pathology, enable monitoring of treatment response, and aid in maintaining an accurate clinical record. In neonates and very young children, obtaining good-quality images can be extremely challenging. We describe four novel and safe techniques for acquiring fundus images in children <1 year of age using a noncontact ultrawide-field camera (Optos Inc, Marlborough, MA), without requiring invasive techniques, such as using an eyelid speculum or anesthesia. We term these imaging positions "quarter prone," "cradle," "modified flying baby," and "modified back-to-front."

Widefield and Ultra-Widefield Retinal Imaging: A Geometrical Analysis

Diabetic retinopathy (DR) often causes a wide range of lesions in the peripheral retina, which can be undetected when using a traditional fundus camera. Widefield (WF) and Ultra-Widefield (UWF) technologies aim to significantly expand the photographable retinal field. We conducted a geometrical analysis to assess the field of view (FOV) of WF and UWF imaging, comparing it to the angular extension of the retina. For this task, we shot WF images using the Zeiss Clarus 500 fundus camera (Carl Zeiss Meditec, Jena, Germany). Approximating the ocular bulb to an ideal sphere, the angular extension of the theoretically photographable retinal surface was 242 degrees. Performing one shot, centered on the macula, it was possible to photograph a retinal surface of ~570 mm², with a FOV of 133 degrees. Performing four shots with automatic montage, we obtained a retinal surface area of ~1100 mm² and an FOV of 200 degrees. Finally, performing six shots with semi-automatic montage, we obtained a retinal surface area of ~1400 mm² and an FOV of 236.27 degrees, which is close to the entire surface of the retina. WF and UWF imaging allow the detailed visualization of the peripheral retina, with significant impact on the diagnosis and management of DR.

Multimodal Imaging, Tele-Education, and Telemedicine in Retinopathy of Prematurity

Retinopathy of prematurity (ROP) is a disease that affects retinal vasculature in premature infants and remains one of the leading causes of blindness in childhood worldwide. ROP screening can encounter some difficulties such as the lack of specialists and services in rural areas. The evolution of technology has helped address these issues and led to the emergence of state-of-the-art multimodal digital imaging devices such fundus cameras with its variable properties, optical coherence tomography (OCT), OCT angiography, and fluorescein angiography which has helped immensely in the process of improving ROP care and understanding the disease pathophysiology. Computer-based imaging analysis and deep learning have recently been demonstrating promising outcomes in regard to ROP diagnosis. Telemedicine is considered an acceptable alternative to clinical examination when optimal circumstances for ROP screening in certain areas are lacking, and the expansion of these programs has been reported. Tele-education programs in ROP have the potential to improve the quality of training to physicians to optimize ROP care.

A retrospective analysis of ultra-widefield photograph (Optos) documentation of retinopathy of prematurity at a tertiary eye care outpatient setup: the Indian Twin Cities ROP Study, report number 11

PURPOSE

To demonstrate the usefulness of ultrawide-field fundus (UWF) photography for documentation in retinopathy of prematurity (ROP).

METHODS

The medical records of infants with ROP who underwent at least one sitting of UWF fundus photography in addition to binocular indirect ophthalmoscopy (BIO) from April 2018 to September 2020 were analyzed retrospectively. BIO was conducted by a trained ROP specialist, and final diagnosis and treatment were based solely on BIO findings. All fundus photographs were captured on Optos UWF camera (Dunfermline, UK) in a flying baby position. Demographic details and fundus findings on BIO and fundus photographs were analyzed.

RESULTS

Of the 187 infants who met inclusion criteria for successful imaging, 22 (11.7%) had findings that were discordant with BIO. Although no posterior disease was missed, 4 infants who received treatment would not have been treated based solely on UWF photography findings. Of the 60 babies whose images did not meet the inclusion criteria for successful imaging, 41 had ROP that required intervention.

CONCLUSIONS

In our patient cohort, UWF photography proved useful in documenting the initial and follow-up findings of preterm babies with ROP.

Comparison of Ultra-Wide Field Photography to Ultra-Wide Field Angiography for the Staging of Sickle Cell Retinopathy

Sickle cell retinopathy (SCR) is classified by Goldberg based on peripheral vascular changes. Ultra-wide field (UWF) imaging has enhanced visualization of the peripheral retina. However, there is no consensus on the optimal imaging technique for the screening of SCR. We performed a monocentric observational cross-sectional study to compare UWF fundus photography (UWF-FP) with UWF angiography (UWF-FA). All patients who underwent UWF-imaging (Optos, PLC, Scotland, UK) for screening of sickle cell retinopathy between January 2016 and December 2019 were retrospectively included. Eyes with previous laser treatment or concomitant retinal disease were excluded. UWF-FP images were graded based on the Goldberg classification by four graders with various degrees of experience. UWF-FA pictures were reviewed by an independent retina specialist. Differences in Goldberg staging across UWF-FP and UWF-FA were assessed. A total of 84 eyes of 44 patients were included. Based on UWF-FA, most eyes were stage 2 (77.4%) and 19 were stage 3 (22.6%). The pre-retinal neovascularization detection sensitivity on UWF-FP was 52.6 to 78.9%, depending on the graders. UWF-FA led to a later Goldberg stage of retinopathy, in most cases from stage 1 to stage 2. Neovascularization (stage 3) was not detected by our graders on UWF-FP in 21.1 to 57.9% of eyes. UWP-FP tends to underestimate Goldberg stages of retinopathy compared with UWF-FA and is less accurate when detecting neovascularization in sickle cell retinopathy, which has a direct impact on therapeutic management and prognosis.

Assessment and management of retinopathy of prematurity in the era of anti-vascular endothelial growth factor (VEGF)

The incidence of retinopathy of prematurity (ROP) continues to rise due to the improved survival of very low birth weight infants in developed countries. This epidemic is also fueled by increased survival of preterm babies with variable use of oxygen and a lack of ROP awareness and screening services in resource-limited regions. Improvements in technology and a basic understanding of the disease pathophysiology have changed the way we screen and manage ROP, educate providers and patients, and improve ROP awareness. Advancements in imaging techniques, expansion of telemedicine services, and the potential for artificial intelligence-assisted ROP screening programs have created opportunities to improve ROP care in areas with a shortage of ophthalmologists trained in ROP. To address the gap in provider knowledge regarding ROP, the Global Education Network for Retinopathy of Prematurity (GEN-ROP) created a web-based tele-education training module that can be used to educate all providers involved in ROP, including non-physician ROP screeners. Over the past 50 years, the treatment of severe ROP has evolved from limited treatment modalities to cryotherapy and laser photocoagulation. More recently, there has been growing evidence to support the use of anti-vascular endothelial growth factor (VEGF) agents for the treatment of severe ROP. However, VEGF is known to be important in organogenesis and microvascular maintenance, and given that intravitreal anti-VEGF treatment can result in systemic VEGF suppression over a period of at least 1-12 weeks, there are concerns regarding adverse effects and long-term ocular and systemic developmental consequences of anti-VEGF therapy. Future research in ophthalmology to address the growing burden of ROP should focus on cost-effective fundus imaging devices, implementation of artificial intelligence platforms, updated treatment algorithms with optimal use of anti-VEGF and careful investigation of its long-term effects, and surgical options in advanced ROP. Addressing these unmet needs will aid the global effort against the ROP epidemic and optimize our understanding and treatment of this blinding disease.

Evolving outcomes of surgery for retinal detachment in retinopathy of prematurity: the need for a national service in the United Kingdom : An audit of surgery for acute tractional retinal detachment complicating ROP in the UK

OBJECTIVES

To audit the structural and functional outcomes of surgery for acute tractional retinal detachment due to retinopathy or prematurity between 2004 and 2014 in Oxford UK.

METHODS

Consecutive operations were identified from a surgical log. Clinical data including demography, perioperative data, and retinal outcomes were extracted into a spreadsheet and compared against two international data sets referenced in the method section. Nonparametric tests (Fisher's exact, and the Mann-Whitney U-tests) were used for statistical analysis with a p-value < 0.05 considered significant.

RESULTS

Twenty-nine eyes of 19 babies underwent surgery. The mean age (SD) at final follow-up was 6.4 (3.7) years of age and comparable to the reference data sets. The mean birth weight and gestational age of babies matched the ETROP data set referenced in the method section. Anatomical success was obtained in 16/29 (55.2%) of eyes and more likely with stage 4 ROP than stage 5 disease (p < 0.05). Thirteen of 29 eyes (44.8%) obtained form vision post-operatively. All instances of macular retinal reattachment during follow up were verified with post-operative OCT.

CONCLUSIONS

Surgery for stage 5 ROP is not worthwhile. For stage 4 ROP it yielded better visual outcomes than ETROP but registration for visual impairment was not prevented. Innovation such as endoscopic vitrectomy could yield better outcomes. Earlier detection of vitreoretinal fibrosis could result in timelier referral. A formally funded national service is needed to ring-fence resource to avoid delays in access to surgery, which has a narrow surgical window.

Flying baby optical coherence tomography alters the staging and management of advanced retinopathy of prematurity

PURPOSE

To report the use of flying baby spectral domain optical coherence tomography (SD-OCT) on infants with advanced retinopathy of prematurity (ROP), where clinical findings alone failed to differentiate between retinoschisis and retinal detachment.

METHODS

Prospective, non-interventional case-series study of three premature infants with advanced ROP of clinically uncertain stage, after examination by indirect ophthalmoscopy. To confirm the diagnosis, table-mounted SD-OCT retinal imaging was performed with the infant held in the flying baby position under topical ocular anaesthesia only. Spectral domain optical coherence tomography (SD-OCT) findings were correlated with clinical examination and ultra-widefield scanning laser ophthalmoscopy to determine disease stage and appropriate management.

RESULTS

The flying baby position was well tolerated, and SD-OCT images of central and peripheral retina were successfully obtained in all three cases. Additional information provided by the SD-OCT changed the ROP staging from 3 to 4 in one case, which subsequently required surgical treatment. In two other cases, clinical suspicion of stage 4 ROP was overruled as SD-OCT revealed tractional retinoschisis rather than full-thickness retinal detachment, thereby avoiding the need for immediate surgical intervention.

CONCLUSIONS

In this case-series study, flying baby SD-OCT provided a rapid and widely accessible imaging approach that overruled clinical findings and altered classification and management of infants with advanced ROP. The methodology was suitable for outpatient settings with no risks associated with systemic anaesthesia. The increased use of OCT imaging will make apparent how structural information is useful in management of ROP and may influence future classification of the disease.

Imaging the pediatric retina: An overview

Recent decade has seen a shift in the causes of childhood blinding diseases from anterior segment to retinal disease in both developed and developing countries. The common retinal disorders are retinopathy of prematurity and vitreoretinal infections in neonates, congenital anomalies in infants, and vascular retinopathies including type 1 diabetes, tumors, and inherited retinal diseases in children (up to 12 years). Retinal imaging helps in diagnosis, management, follow up and prognostication in all these disorders. These imaging modalities include fundus photography, fluorescein angiography, ultrasonography, retinal vascular and structural studies, and electrodiagnosis. Over the decades there has been tremendous advances both in design (compact, multifunctional, tele-consult capable) and technology (wide- and ultra-wide field and noninvasive retinal angiography). These new advances have application in most of the pediatric retinal diseases though at most times the designs of new devices have remained confined to use in adults. Poor patient cooperation and insufficient attention span in children demand careful crafting of the devices. The newer attempts of hand-held retinal diagnostic devices are welcome additions in this direction. While much has been done, there is still much to do in the coming years. One of the compelling and immediate needs is the pediatric version of optical coherence tomography angiography. These needs and demands would increase many folds in future. A sound policy could be the simultaneous development of adult and pediatric version of all ophthalmic diagnostic devices, coupled with capacity building of trained medical personnel.

Clinical Characteristics of Eyes Showing a Discrete Margin of Different Retinal Reflectivity

BACKGROUND AND OBJECTIVE

To evaluate the clinical characteristics of discrete margins of different retinal reflectivity (DMDRR) in ultra-widefield fundus photography.

PATIENTS AND METHODS

This DMDRR comprises a discrete border, with differing patterns of reflectivity on either side. Spectral-domain optical coherence tomography was performed on both the macula and the margin. The incidences of epiretinal membrane (ERM) and peripheral retinal pathologies of patients with a DMDRR (n = 36) were compared with a control group (n = 41).

RESULTS

An ellipsoid zone (EZ) defect at the DMDRR was detected in 34 eyes (92.2%), and vitreous traction was detected in 20 eyes (55.6%). A significantly higher proportion of eyes in the DMDRR group had an ERM, retinal hole, and cystic retinal tuft compared with the control group (P = .022, P = .010, and P < .001, respectively).

CONCLUSIONS

The DMDRR indicates EZ disruption that may originate from vitreous traction. Meticulous observation for vitreoretinal interface diseases is mandatory for these patients. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:273-280.].

Ultra-wide field retinal imaging: A wider clinical perspective

The peripheral retina is affected in a variety of retinal disorders. Traditional fundus cameras capture only a part of the fundus even when montaging techniques are used. Ultra-wide field imaging enables us to delve into the retinal periphery in greater detail. It not only facilitates assessing color images of the fundus, but also fluorescein angiography, indocyanine green angiography, fundus autofluorescence, and red and green free images. In this review, a literature search using the keywords "ultra-widefield imaging", "widefield imaging", and "peripheral retinal imaging" in English and non-English languages was done and the relevant articles were included. Ultra-wide field imaging has made new observations in the normal population as well as in eyes with retinal disorders including vascular diseases, degenerative diseases, uveitis, age-related macular degeneration, retinal and choroidal tumors and hereditary retinal dystrophies. This review aims to describe the utility of ultra-wide field imaging in various retinal disorders.

Retinal imaging in infants

Digital retinal imaging is at the core of a revolution that is continually improving the screening, diagnosis, documentation, monitoring, and treatment of infant retinal diseases. Historically, imaging the retina of infants had been limited and difficult to obtain. Recent advances in photographic instrumentation have significantly improved the ability to obtain high quality multimodal images of the infant retina. These include color fundus photography with different camera angles, ultrasonography, fundus fluorescein angiography, optical coherence tomography, and optical coherence tomography angiography. We provide a summary of the current literature on retinal imaging in infants and highlight areas where further research is required.

ULTRA-WIDE-FIELD IMAGING AND INTRAVENOUS FUNDUS FLUORESCEIN ANGIOGRAPHY IN INFANTS WITH RETINOPATHY OF PREMATURITY

PURPOSE

To determine the feasibility of ultra-wide-field imaging and ultra-wide-field intravenous fundus fluorescein angiography (UWF-IV-FFA) in infants with retinopathy of prematurity (ROP) using Optos 200Tx.

METHODS

We performed Optos 200Tx capturing on 32 premature infants (14 females) and UWF-IV-FFA with Optos 200Tx on 12 of the 32 infants between April 2017 and July 2018 at the affiliated eye hospital of Wenzhou Medical University and analyzed their fundus images.

RESULTS

Ultra-wide-field color images were acquired from 32 infants (64 eyes). UWF-IV-FFA was performed successfully in 12 premature infants (24 eyes). No adverse events were observed. The ultra-wide-field Optos 200Tx color images and UWF-IV-FFA images revealed Stages 1, 2, and 3 ROP and aggressive posterior ROP.

CONCLUSION

Ultra-wide-field imaging and intravenous fundus fluorescein angiography using Optos 200Tx are feasible in infants with ROP, which have the potential to screen, diagnose, and follow-up for ROP.

Retinal image mosaicking using scale-invariant feature transformation feature descriptors and Voronoi diagram

Purpose: Peripheral retinal lesions substantially increase the risk of diabetic retinopathy and retinopathy of prematurity. The peripheral changes can be visualized in wide field imaging, which is obtained by combining multiple images with an overlapping field of view using mosaicking methods. However, a robust and accurate registration of mosaicking techniques for normal angle fundus cameras is still a challenge due to the random selection of matching points and execution time. We propose a method of retinal image mosaicking based on scale-invariant feature transformation (SIFT) feature descriptor and Voronoi diagram. Approach: In our method, the SIFT algorithm is used to describe local features in the input images. Then the input images are subdivided into regions based on the Voronoi method. Each pair of Voronoi regions is matched by the method zero mean normalized cross correlation. After matching, the retinal images are mapped into the same coordinate system to form a mosaic image. The success rate and the mean registration error (RE) of our method were compared with those of other state-of-the-art methods for the P category of the fundus image registration database. Results: Experimental results show that the proposed method accurately registered 42% of retinal image pairs with a mean RE of 3.040 pixels, while a lower success rate was observed in the other four state-of-the-art retinal image registration methods GDB-ICP (33%), Harris-PIIFD (0%), HM-2016 (0%), and HM-2017 (2%). Conclusions: The proposed method outperforms state-of-the-art methods in terms of quality and running time and reduces the computational complexity.

Multimodal Imaging Correlation of the Concentric Macular Rings Sign in Foveal Hypoplasia: A Distinctive Henle Fiber Layer Geometry

PURPOSE

To expand the multimodal imaging correlation of the concentric macular rings (CMR) sign seen on ultra-widefield fundus photography in patients with foveal hypoplasia.

DESIGN

Retrospective case series.

PARTICIPANTS

Thirty-two patients with foveal hypoplasia who demonstrated the CMR sign on ultra-widefield fundus photography.

METHODS

Inclusion criterion was the presence of a CMR sign detected on ultra-widefield fundus photography.

MAIN OUTCOME MEASURES

Noninvasive multimodal retinal imaging, including ultra-widefield fundus photography, structural OCT, near-infrared reflectance, and blue fundus autofluorescence, were investigated. Horizontal dense B-scans and en face OCT images were acquired.

RESULTS

Evaluation of all patients (n = 32 patients) demonstrated a CMR sign on ultra-widefield fundus photography. Structural OCT scans were consistent with foveal hypoplasia in all patients. En face OCT images acquired at the level of the Henle fiber layer highlighted similar concentric rings around the location of the incipient fovea. The series of concentric rings was not visible at any other level of the macula. A significant correlation was found between the horizontal diameter of the largest outer ring and foveal hypoplasia grades (P < 0.0001).

CONCLUSIONS

The CMR sign seen on ultra-widefield fundus imaging may be a distinctive feature of foveal hypoplasia and can support this diagnosis, especially in patients in whom OCT cannot be performed (patients with poor fixation or nystagmus or young children). Multimodal imaging correlation suggests that these concentric rings occur exclusively at the level of the Henle fiber layer. This distinctive Henle fiber layer geometry may reflect an arrested development stage in the timeline of foveal maturation.

Trans-pars-planar illumination enables a 200° ultra-wide field pediatric fundus camera for easy examination of the retina

This study is to test the feasibility of using trans-pars-planar illumination for ultra-wide field pediatric fundus photography. Fundus examination of the peripheral retina is essential for clinical management of pediatric eye diseases. However, current pediatric fundus cameras with traditional trans-pupillary illumination provide a limited field of view (FOV), making it difficult to access the peripheral retina adequately for a comprehensive assessment of eye conditions. Here, we report the first demonstration of trans-pars-planar illumination in ultra-wide field pediatric fundus photography. For proof-of-concept validation, all off-the-shelf optical components were selected to construct a lab prototype pediatric camera (PedCam). By freeing the entire pupil for imaging purpose only, the trans-pars-planar illumination enables a 200° FOV PedCam, allowing easy visualization of both the central and peripheral retina up to the ora serrata. A low-cost, easy-to-use ultra-wide field PedCam provides a unique opportunity to foster affordable telemedicine in rural and underserved areas.

Clinic-based ultra-wide field retinal imaging in a pediatric population

Background

Pediatric retinal disorders, although uncommon, can be challenging to assess in the clinic setting and often requires an exam under anesthesia. The purpose of our study was to evaluate the use of ultra-wide field retinal imaging in children without sedation in an outpatient clinic.

Methods

We performed a retrospective case series of patients 18 years or younger who received ultra-wide field imaging over a one year period. The age, gender, and clinical course were documented. Color fundus and red-free images were reviewed to assess field of view. Ultra-wide field autofluorescence (UWF-FAF) was evaluated for abnormal autofluorescence patterns and ultra-wide field fluorescein angiography (UWF-FA) was assessed for angiographic phase and field of view.

Results

A total of 107 eyes of 55 patients with a mean age of 11.1 years (SD 3.7 years, range 3–18 years) were evaluated. Twenty-seven (49%) patients were male. The most common diagnosis was retinopathy of prematurity (7 of 55 patients, 12.7%) followed by trauma (7.4%), Coats disease (7.4%), and rhegmatogenous retinal detachment (7.4%). The number of quadrants visualized anterior to the equator correlated with patient age (r = 0.4, p < 0.01). On UWF-FA, 6 of 14 patients (43%) had images of the arterial phase captured and 14 of 14 patients (100%) had images of the venous phase or later captured.

Conclusions

We demonstrated that UWF imaging is obtainable in children as young as 3 years old without sedation. UWF fundus photography, UWF-FAF and UWF-FA were useful clinical adjuvants to examination and provide additional information for documenting and monitoring pediatric retinal diseases.

Wide-field imaging of sickle retinopathy

Background

Wide-field imaging is a newer retinal imaging technology, capturing up to 200 degrees of the retina in a single photograph. Individuals with sickle cell retinopathy commonly exhibit peripheral retinal ischemia. Patients with proliferative sickle cell retinopathy develop pathologic retinal neovascularization of the peripheral retina which may progress into sight-threatening sequelae of vitreous hemorrhage and/or retinal detachment. The purpose of this review is to provide an overview of current and future applications of wide-field retinal imaging for sickle cell retinopathy, and recommend indications for best use.

Main body

There are several advantages to wide-field imaging in the clinical management of sickle cell disease patients. Retrospective and prospective studies support the success of wide-field imaging in detecting more sickle cell induced retinal microvascular abnormalities than traditional non-wide-field imaging. Clinicians can easily capture a greater extent of the retinal periphery in a patient's clinical baseline imaging to follow the changes at an earlier point and determine the rate of progression over time. Wide-field imaging minimizes patient and photographer burden, necessitating less photos and technical skill to capture the peripheral retina. Minimizing the number of necessary images can be especially helpful for pediatric patients with sickle cell retinopathy. Wide-field imaging has already been successful in identifying new biomarkers and risk factors for the development of proliferative sickle cell retinopathy. While these advantages should be considered, clinicians need to perform a careful risk-benefit analysis before ordering this test. Although wide-field fluorescein angiography successfully detects additional pathologic abnormalities compared to traditional imaging, a recent research study suggests that peripheral changes differentially detected by wide-field imaging may not change clinical management for most sickle cell patients.

Conclusions

While wide-field imaging may not carry a clinically significant direct benefit to all patients, it shows future promise in expanding our knowledge of sickle cell retinopathy. Clinicians may monitor peripheral retinal pathology such as retinal ischemia and retinal neovascularization over progressive time points, and use sequential wide-field retinal images to monitor response to treatment. Future applications for wide-field imaging may include providing data to facilitate machine learning, and potential use in tele-ophthalmology screening for proliferative sickle retinopathy.

Comparisons of Effective Fields of Two Ultra-Widefield Ophthalmoscopes, Optos 200Tx and Clarus 500

Purpose

To compare the effective fields of the Optos 200Tx® and Clarus 500™, two ultra-widefield ophthalmoscopes, based on their ability to image branches of retinal vessel in the four retinal quadrants.

Methods

Ninety retinal images from 90 patients with various eye diseases were studied. All patients had undergone 200° retinal imaging to obtain a single image of Optos (O) and the montage of two images of the Clarus (C). The highest number of traceable vessel branches in the four retinal quadrants was determined by two masked raters. An image was classified as “O > C” when the number of identifiable branch was greater in the Optos than the Clarus, as “O = C” when the number was equal and as “O < C” when the number was fewer in the Optos than the Clarus.

Results

The appearance probability of “O > C” was significantly higher at the upper temporal quadrant than “O < C” (p < 0.01 for both raters). In contrast, the appearance probability of “O < C” was significantly higher at the lower nasal quadrant than “O > C” (p < 0.01 for both raters). There were no significant differences in the appearance probability between “O > C” and “O < C” at the other two retinal quadrants (p > 0.50 for both raters).

Conclusions

These results demonstrate that the effective field of views was different between the two devices at different retina quadrants. Further studies are needed to clarify possible factors such as artifacts by the eyelashes, differences in the depth of focus, motion of the device, and different locations of the images on the effective field of views.

Smartphone guided wide-field imaging for retinopathy of prematurity in neonatal intensive care unit - a Smart ROP (SROP) initiative

Purpose

To suggest a low cost, non-contact smartphone-based screening system in retinopathy of prematurity (ROP), and to illustrate its potential clinical application as a potential future tool for teleophthalmology.

Methods

Neonatal intensive care unit (NICU)-based bedside ROP screening done between January 2018 and May 2018. Documentation of ROP was done by using a smartphone and +40D, +28D, or +20D indirect non-contact condensing lenses. By using the coaxial light source of the phone, this system works as an indirect ophthalmoscope that creates a digital image of the fundus. With smartphone-based camera we extracted high-quality still images extracted from the video clip.

Results

Total of 228 eyes of 114 infants screened for ROP between January 2018 and May 2018. Incidence of total ROP was 23.68%, out of which incidence of type 1 ROP was 8.77%. After initial screening with indirect ophthalmoscope, we uesd smartphone imaging to document ROP in 28 eyes out of 55 eyes having ROP. Image quality was good in 89.28% eyes. Field of view vary from 46°, 53°, and 90° with +20D, +28D, and +40D indirect condensing lenses, respectively, which gives excellent images for bedside ROP documentation.

Conclusion

The described technique of smartphone fundus photography is a light weight, cost-effective, user friendly, high-quality wide-field fundus photographs for bedside documentation of ROP in NICUs using readily available instruments that are handy and portable with simple power sources. Smartphones has the potential to be operated with only one hand. It can also be used as a future telescreening device.

Quantitative comparisons of ultra-widefield images of model eye obtained with Optos® 200Tx and Optos® California

Background

To compare the quality of the ultra-widefield images acquired by Optos® 200Tx to those acquired by Optos® California.

Methods

Images of the posterior surface of a Gullstrand’s model eye obtained by Optos® 200Tx were compared to those obtained by Optos® California in terms of the angular field of view and the symmetry of the image, i.e., vertical and horizontal aspect ratios at the center (0°) and at the periphery (40° and 80°) in each direction. In addition, we compared the enlargement of the image on the posterior surface as the square ratio, and the differences in the contrasts.

Results

No significant differences were detected in the angular field of view between the two instruments. The aspect ratios showed that the Optos® California had more symmetrical images than the Optos® 200Tx at the center (0.98 vs 0.89, P < 0.01) and at the 40° periphery (0.93–1.04, △0.11 vs 0.79–1.01, △0.22) and 80° periphery (0.81–1.25, △0.44 vs 0.42–1.12, △0.70) in each direction. The amplitude of the square ratio of the Optos® California was smaller at 40° periphery (1.16–1.28, △0.12 vs 1.06–1.37, △0.31) and 80° periphery (2.12–2.46, △0.34 vs 1.14–3.29, △2.15). The contrast of the Optos® California images was significantly higher in the posterior pole (0.09 vs 0.12, P < 0.01), upper (0.07 vs 0.03, P < 0.01), and right (0.12 vs 0.07, P < 0.01) peripheries.

Conclusion

Optos® California can record equal angular widefield images to Optos® 200Tx and more symmetrical images with higher contrast in the posterior pole, upper and right peripheries.

Surface-Coil MRI for Small Peripheral Choroidal Melanoma: Imaging in a Rabbit Eye Model

Introduction

Imaging of small peripheral choroidal melanomas remains challenging in clinical and experimental settings, requiring wide-field ophthalmoscopy modalities. In this study, we applied surface-coil MRI to assess imaging feasibility for small peripherally located choroidal melanoma in a rabbit eye model.

Methods

A female albino rabbit with a body weight of 2.8 kg was immunosuppressed with intramuscular cyclosporine 15 mg/kg daily for 3 days prior to inoculation of 14 million 92.1 line melanoma cells into the peripheral suprachoroidal space of the right eye. The experimental animal continued to receive the same dosage of cyclosporine daily for 26 days postinoculation until the day of sacrifice. On that interval, it underwent surface-coil MRI scanning using various protocols and models subsequently sacrificed to allow histological evaluation. A comparative examination of various MRI sequences for optimal lesion imaging was performed, based on semiquantitative criteria.

Results

Imaging quality and superimposed artifacts varied across different sequences and the optimal tumor delineation from adjacent tissues was achieved in T1-weighted sequences.

Conclusions

MRI of small peripheral choroidal melanomas is feasible in a rabbit model using surface coils, particularly in T1-weighted sequences. Findings may be used as a basis for further development of this technique for experimental and clinical applications.

Binocular Indirect Ophthalmoscopy Complements Non-contact Wide-field Imaging with Optos to Treat a Baby Outside ETROP Guidelines

We report a male premature baby who was born at 24 weeks gestation weighing 600 grams. There was bilateral stage 2, zone 2 retinopathy of prematurity (ROP) without plus disease at 38 weeks postmenstrual age. Ultra-wide-field Optomap images obtained 1 week later showed no change in ROP stage. At 40 weeks postmenstrual age, stage 3, zone 2 ROP was detected using binocular indirect ophthalmoscopy and documented using Optos. Minor tortuosity and dilation of vessels was interpreted as pre-plus disease. One week later, at 41 weeks postmenstrual age, Optomap images identified progressive extraretinal fibroproliferation in the nasal quadrant. As a result, the baby was treated with fundus laser photocoagulation.

The clinical relevance of visualising the peripheral retina

Recent developments in imaging technologies now allow the documentation, qualitative and quantitative evaluation of peripheral retinal lesions. As wide field retinal imaging, capturing both the central and peripheral retina up to 200° eccentricity, is becoming readily available the question is: what is it that we gain by imaging the periphery? Based on accumulating evidence it is clear that findings in the periphery do not always associate to those observed in the posterior pole. However, the newly acquired information may provide useful clues to previously unrecognised disease features and may facilitate more accurate disease prognostication. In this review, we explore the anatomy and physiology of the peripheral retina, focusing on how it differs from the posterior pole, recount the history of peripheral retinal imaging, describe various peripheral retinal lesions and evaluate the overall relevance of peripheral retinal findings to different diseases.

Spectral-Domain OCT Findings of Retinal Vascular-Avascular Junction in Infants with Retinopathy of Prematurity

PURPOSE

Bedside examination of premature infants at risk for retinopathy of prematurity (ROP) is predominantly performed with ophthalmoscopic en face viewing of the retina. While postmortem retinal microstructures have been studied at the vascular-avascular junction, a critical location for pathogenesis of ROP, to date this has not been possible in vivo. Here we present bedside, non-sedated in vivo cross-sectional imaging and analysis of retinal microstructures at the vascular-avascular junction in infants with ROP using handheld spectral-domain optical coherence tomography (SDOCT).

DESIGN

Prospective observational study.

PARTICIPANTS

Eleven preterm infants consented for research imaging during ROP screening examinations.

METHODS

We imaged the vascular-avascular junction in the temporal retina using a SDOCT system (Envisu, Bioptigen Inc., NC) in 18 eyes from 11 preterm infants with zone I or II, stage 0 through 4 ROP. B-scan and en face images were analyzed and compared to historical light micrographs.

MAIN OUTCOME MEASURES

SDOCT morphology at the vascular-avascular junction.

RESULTS

Multiple bedside SDOCT findings at the vascular-avascular junction were comparable to historic light micrographs: thickened inner retinal ridge structure in stage 2 ROP was comparable to thickened vanguard and rear guard cells in micrographs; vascular tufts on the posterior retinal surface in stage 2 ROP, broad arcs of neovascularization above the retina in stage 3 ROP, and splitting of inner retinal layers into clefts on either side of neovascularization mimicked findings of historic light micrographs. A unique findings was thickening of the avascular inner retinal band adjacent to neovascularization. On SDOCT imaging over several weeks, neovascularization and retinal clefts diminished after intravitreal bevacizumab therapy.

CONCLUSIONS

Retinal morphology at the vascular-avascular junction imaged with handheld SDOCT is consistent with known histopathology, and provide the advantage of monitoring change in vivo over time. These unique findings provide new insights into preterm retinal neurovascular development in ROP.

Handheld Retinal Oximetry in Healthy Young Adults

Purpose

The objective of this study was to measure the relative retinal oxygen saturation with a prototype, mobile handheld oximeter in upright and supine position and to compare these measurements to the gold standard Oxymap T1 retinal oximeter in upright position. A handheld oximeter is needed for measurements of infants with retinopathy of prematurity as well as acutely injured and bedridden adults.

Methods

Healthy volunteers (age 18–35) were recruited at the Leiden University Medical Center. Retinal images were acquired with the handheld oximeter and the Oxymap T1. Both cameras are dual-wavelength oximeters and acquire images with wavelengths of 570 and 600 nm. Retinal oxygen saturation values were determined for both the handheld camera and the Oxymap T1.

Results

Twenty-one subjects (age 25 ± 2 years) were included. In upright position, the oxygen saturation for the arterioles was 92.2% to 4.9% vs. 95.5% ± 4.2% and for the venules 57.9% ± 10.2% vs. 57.7% ± 6.4% for the handheld camera and Oxymap T1, respectively. The oxygen saturation was higher in the arterioles than the venules for both cameras (P < 0.05). In supine position, measured with the handheld oximeter, the oxygen saturation in the arterioles was 92.3% ± 5.8% and 59.2% ± 6.1% in the venules.

Conclusions

Performance of the prototype, mobile handheld oximeter Corimap camera compares well with the Oxymap T1, with a slightly larger standard deviation in oxygen saturation measurements, both in upright and supine patients.

Translation Relevance

To date, to our knowledge, no oximeters are available for handheld use and for measurement in supine position in infants and bedridden adults. Here we tested such an oximeter and show that its performance compares well with that of the gold standard Oxymap T1 in healthy adults.

Retinopathy of prematurity: preferred practice patterns among pediatric ophthalmologists

Purpose

The treatment of retinopathy of prematurity (ROP) is not standardized and can vary significantly between providers. This study aims to determine preferred practices in treating ROP by globally surveying pediatric ophthalmologists.

Methods

Between January and February 2017, an international pediatric ophthalmology interest group was invited to complete an anonymous survey of 18 questions. The main objectives were to determine the preferred first line of treatment for ROP, the preferred dosage of intravitreal bevacizumab (IVB) used, and the outcome and possible complications following bevacizumab injection.

Results

Out of 101 pediatric ophthalmologists, 72 (71.8%) stated that they had direct involvement in the treatment of ROP. When presented with type 1 ROP which requires treatment, 69 ophthalmologists (68.3%) stated that they prefer laser treatment over bevacizumab, and 33 ophthalmologists (32.7%) stated they would recommend bevacizumab as a first choice. Ninety-three ophthalmologists (92.1%) reported the success of 1 laser treatment between 75% and 100%, and 35 ophthalmologists (34.7%) perceive bevacizumab to be 75%–100% successful. Half dose of adult-prescribed bevacizumab at 0.625 mg/0.05 mL was preferred by 47 of the ophthalmologists (46.5%). No cases of endophthalmitis were reported with intravitreal injection.

Conclusion

Laser photoablation remains the preferred mode of treatment for ROP among surveyed ophthalmologists across the world. Though bevacizumab is currently being used, this form of treatment is not as common, primarily due to the unknown safety profile and potential long-term ramifications of the drug.

Fundus imaging in newborn children with wide-field scanning laser ophthalmoscope

PURPOSE

Current fundus imaging in newborn babies requires mydriatics, eye specula and corneal contact. We propose that a scanning laser ophthalmoscope (SLO) allows ultra wide-field imaging with reduced stress for the child.

METHODS

This prospective observational single centre study was conducted in Landspítali, University Hospital, Reykjavik, Iceland. In this study, a noncontact wide-field SLO (Optomap 200Tx) was used to image the retina in healthy full-term newborns without the use of mydriatics or eye specula. The child was held by one of the parents, while one of the researchers supported the child's head in front of the SLO camera for alignment and opened the eye with either a finger or a cotton tip.

RESULTS

Fifty-nine participants were recruited (34 females). The mean age was 16 days, and the mean gestational age was 40 ± 1 weeks at the time of imaging. Ultra-wide-field (200°) images were obtained of 44 participants. Twenty-seven participants (61%) had at least one ultra wide-field image with the optic disc and vessel segments in all quadrants of the fundus visible and in focus. No retinal pathology was found in the participants with the exception of one participant with small retinal haemorrhages.

CONCLUSION

Scanning laser ophthalmoscope (SLO) ultra-wide-field fundus imaging is feasible in healthy full-term newborns without corneal contact, eye speculum or mydriatics. This approach could be an improvement for retinal imaging in newborn infants. Eye movement of the infant, whether asleep or awake, influenced which part of the fundus was captured, but focus and image quality were generally good.

Adiponectin Mediates Dietary Omega-3 Long-Chain Polyunsaturated Fatty Acid Protection Against Choroidal Neovascularization in Mice

Purpose

Neovascular age-related macular degeneration (AMD) is a major cause of legal blindness in the elderly. Diets with omega3-long-chain-polyunsaturated-fatty-acid (ω3-LCPUFA) correlate with a decreased risk of AMD. Dietary ω3-LCPUFA versus ω6-LCPUFA inhibits mouse ocular neovascularization, but the underlying mechanism needs further exploration. The aim of this study was to investigate if adiponectin (APN) mediated ω3-LCPUFA suppression of neovessels in AMD.

Methods

The mouse laser-induced choroidal neovascularization (CNV) model was used to mimic some of the inflammatory aspect of AMD. CNV was compared between wild-type (WT) and Apn^−/− mice fed either otherwise matched diets with 2% ω3 or 2% ω6-LCPUFAs. Vldlr^−/− mice were used to mimic some of the metabolic aspects of AMD. Choroid assay ex vivo and human retinal microvascular endothelial cell (HRMEC) proliferation assay in vitro was used to investigate the APN pathway in angiogenesis. Western blot for p-AMPKα/AMPKα and qPCR for Apn, Mmps, and IL-10 were used to define mechanism.

Results

ω3-LCPUFA intake suppressed laser-induced CNV in WT mice; suppression was abolished with APN deficiency. ω3-LCPUFA, mediated by APN, decreased mouse Mmps expression. APN deficiency decreased AMPKα phosphorylation in vivo and exacerbated choroid-sprouting ex vivo. APN pathway activation inhibited HRMEC proliferation and decreased Mmps. In Vldlr^−/− mice, ω3-LCPUFA increased retinal AdipoR1 and inhibited NV. ω3-LCPUFA decreased IL-10 but did not affect Mmps in Vldlr^−/− retinas.

Conclusions

APN in part mediated ω3-LCPUFA inhibition of neovascularization in two mouse models of AMD. Modulating the APN pathway in conjunction with a ω3-LCPUFA-enriched-diet may augment the beneficial effects of ω3-LCPUFA in AMD patients.

ω-3 and ω-6 long-chain PUFAs and their enzymatic metabolites in neovascular eye diseases

Neovascular eye diseases, including retinopathy of prematurity, diabetic retinopathy, and age-related macular degeneration, threaten the visual health of children and adults. Current treatment options, including anti-vascular endothelial growth factor therapy and laser retinal photocoagulation, have limitations and are associated with adverse effects; therefore, the identification of additional therapies is highly desirable. Both clinical and experimental studies show that dietary ω-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFAs) reduce retinal and choroidal angiogenesis. The ω-3 LC-PUFA metabolites from 2 groups of enzymes, cyclooxygenases and lipoxygenases, inhibit [and the ω-6 (n-6) LC-PUFA metabolites promote] inflammation and angiogenesis. However, both of the ω-3 and the ω-6 lipid products of cytochrome P450 oxidase 2C promote neovascularization in both the retina and choroid, which suggests that inhibition of this pathway might be beneficial. This review summarizes our current understanding of the roles of ω-3 and ω-6 LC-PUFAs and their enzymatic metabolites in neovascular eye diseases.

Non-contact ultra-widefield retinal imaging of infants with suspected abusive head trauma

PurposeThe purpose of the study was to audit the use of non-contact ultra-widefield retinal imaging in infants with suspected abusive head trauma (AHT) using the Optos P200MA Scanning Laser Ophthalmoscope.Patients and methodsA retrospective, observational case series. Ten eyes of five consecutive infants (aged 1-15 months) with suspected (or in 1 case, known) AHT referred for an ophthalmological opinion were included. Each infant underwent non-contact ultra-widefield retinal imaging using the Optos P200MA scanning laser ophthalmoscope. Optos fundus fluorescein angiography (FFA) was performed in one infant with oral sedation. The other four infants did not require sedation. The main outcome measure was the acquisition of a single, definitive ultra-widefield retinal image in each eye. Safety was audited by determining adverse changes in heart rate and oxygen saturations that required cessation of imaging.ResultsThe Optos P200MA ultra-widefield scanning laser ophthalmoscope acquired good quality retinal images in all infants. Documentation of acute, widespread retinal haemorrhages contributed to a diagnosis of AHT in three infants. Chronic pre-macular haemorrhage and macular schisis were documented by FFA in a fourth infant. The absence of retinal haemorrhages was documented in a fifth infant contributing to the exclusion of a diagnosis of AHT. There were no adverse safety signals in any infant in this series.ConclusionThe Optos P200MA ultra-widefield scanning laser ophthalmoscope appears safe to use in infants with suspected AHT, providing high-quality retinal images in a single frame without ocular contact. Optos P200MA may be used as alternative to RetCam to document retinal haemorrhages in stable infants with suspected AHT.

Photographic assessment of retinal hemorrhages in infant head injury: the Childhood Hemorrhagic Retinopathy Study

BACKGROUND

Retinal hemorrhages (RH) in babies in the absence of severe trauma or a medical cause have been strongly associated with abusive head trauma (AHT). We examined the pattern of RH in accidental head injury and AHT objectively using widefield retinal imaging.

METHODS

A total of 118 infants and children 1-36 months of age admitted with head injuries at two centers were included in this prospective, consecutive, comparative cohort study. Dilated fundus examination was performed with indirect ophthalmoscopy and widefield imaging. Designation of AHT was made using predetermined criteria independent of retinal findings. Retinal images were graded by two independent observers.

RESULTS

There were 21 cases of AHT. RH were present in 14 cases (66%); macular retinoschisis or retinal folds, in 8 (38%). There were 86 cases of accidental head injuries, with RH present in 2 (2%); there were none with retinal folds or retinoschisis. In cases of head injury with intracranial hemorrhage, the positive likelihood ratio of AHT with RH was 5.7 (95% CI, 2.6-12.00) and negative likelihood ratio was 0.26 (95% CI, 0.11-0.62). A severe, panretinal pattern with multilayered hemorrhages was the most specific for AHT.

CONCLUSIONS

Our imaging study confirmed that RH in infants with head injury have a high positive likelihood ratio for AHT. A severe hemorrhagic retinopathy, particularly in association with perimacular folds or macular retinoschisis, has the highest positive predictive value for AHT.

Update on wide- and ultra-widefield retinal imaging

The peripheral retina is the site of pathology in many ocular diseases and ultra-widefield (UWF) imaging is one of the new technologies available to ophthalmologists to manage some of these diseases. Currently, there are several imaging systems used in practice for the purpose of diagnostic, monitoring disease progression or response to therapy, and telemedicine. These include modalities for both adults and pediatric patients. The current systems are capable of producing wide- and UWF color fundus photographs, fluorescein and indocyanine green angiograms, and autofluorescence images. Using this technology, important clinical observations have been made in diseases such as diabetic retinopathy, uveitides, retinal vascular occlusions and tumors, intraocular tumors, retinopathy of prematurity, and age-related macular degeneration. Widefield imaging offers excellent postoperative documentation of retinal detachment surgery. New applications will soon be available to integrate this technology into large volume routine clinical practice.

ULTRA-WIDEFIELD FUNDUS IMAGING: A Review of Clinical Applications and Future Trends

PURPOSE

To review the basic principles of ultra-widefield fundus imaging and discuss its clinical utility for a variety of retinal and choroidal disorders.

METHODS

A systematic review of the PubMed database was performed using the search terms Optos, optomap, panoramic, ultra-widefield, wide-angle, and ellipsoid mirror. This yielded 158 publications of which 128 were selected based on content and relevance.

RESULTS

A total of 128 articles pertaining to ultra-widefield imaging were cited in this review.

CONCLUSION

Optos ultra-widefield imaging has become an essential tool for the identification of peripheral retinal and vascular pathology. The high resolution and multimodal capabilities of this device are also providing new insights into a variety of disorders, even those that primarily involve the posterior pole. Although the presence of artifact and the need for clinical validation are significant hurdles to more widespread use, ultra-widefield is evolving to become the standard-of-care imaging modality for many diseases and is finding new clinical and research applications such as for screening and telemedicine.

Retinal Oximetry with Scanning Laser Ophthalmoscope in Infants

Purpose

Dual wavelength retinal oximetry has been developed for adults, but is not available for infants. Retinal oximetry may provide insight into the pathophysiology of oxygen-mediated diseases like retinopathy of prematurity. More insight in the oxygen metabolism of the retina in infants may provide valuable clues for better understanding and subsequent prevention or treatment of the disease. The measurements of oxygen saturation are obtained with two fundus images simultaneously captured in two different wavelengths of light. The comparison in light absorption of oxygenated and deoxygenated hemoglobin can be used to estimate the oxygen saturation within the retinal vessels by means of a software algorithm. This study aims to make retinal oximetry available for neonates. The first step towards estimating retinal oxygen saturation is determining the optical density ratio. Therefore, the purpose of this study is to image healthy newborn infants with a scanning laser ophthalmoscope and determine the optical density ratio for retinal oximetry analysis.

Methods

Images of the retina of full-term healthy infants were obtained with an SLO, Optomap 200Tx (Optos), with two laser wavelengths (532nm and 633nm). The infant lay face down on the lower arm of the parent, while the parent supported the chest and chin with one hand, and stabilized the back with the other hand. No mydriatics or eyelid specula were used during this study. The images were analyzed with modified Oxymap Analyzer software for calculation of the Optical Density Ratio (ODR) and vessel width. The ODR is inversely and approximately linearly related to the oxygen saturation. Measurements were included from the superotemporal vessel pair. A paired t-test was used for statistical analysis.

Results

Fifty-nine infants, (58% female), were included with mean gestational age of 40 ± 1.3 weeks (mean ± SD) and mean post-natal age of 16 ± 4.8 days. A total of 28 images were selected for retinal oximetry analysis. The ODR was 0.256 ± 0.041 for the arterioles and 0.421 ± 0.089 for the venules (n = 28, p < 0.001). The measured vessel-width for the arterioles was 14.1 ± 2.7 pixels and for the venules 19.7 ± 3.7 pixels (n = 28, p < 0.001).

Conclusions

Retinal oximetry can be performed in newborn infants by combining an SLO and a dual-wavelength algorithm software. Sensitivity of the approach is indicated by the fact that the ODR measurements are significantly different between the arterioles and the venules. However, more variability in ODR is seen with the SLO approach in babies than is seen with conventional oximetry in adults. This approach is completely non-invasive, non-contact and even avoids the use of mydriatics or eyelid specula.

Feasibility and clinical utility of ultra-widefield indocyanine green angiography

PURPOSE

To evaluate the feasibility and clinical utility of a novel noncontact scanning laser ophthalmoscope-based ultra-widefield indocyanine green angiographic system.

METHODS

Ultra-widefield indocyanine green angiographic images were captured using a modified Optos P200Tx that produced high-resolution images of the choroidal vasculature with up to a 200° field. Ultra-widefield indocyanine green angiography was performed on patients with a variety of retinal conditions to assess utility of this imaging technique for diagnostic purposes and disease treatment monitoring.

RESULTS

Ultra-widefield indocyanine green angiography was performed on 138 eyes of 69 patients. Mean age was 58 ± 16.9 years (range, 24-85 years). The most common ocular pathologies imaged included central serous chorioretinopathy (24 eyes), uveitis (various subtypes, 16 eyes), age-related macular degeneration (12 eyes), and polypoidal choroidal vasculopathy (4 eyes). In all eyes evaluated with ultra-widefield indocyanine green angiography, high-resolution images of choroidal and retinal circulation were obtained with sufficient detail out to 200° of the fundus.

CONCLUSION

In this series of 138 eyes, scanning laser ophthalmoscope-based ultra-widefield indocyanine green angiography was clinically practical and provided detailed images of both the central and peripheral choroidal circulation. Future studies are needed to refine the clinical value of this imaging modality and the significance of peripheral choroidal vascular changes in the diagnosis, monitoring, and treatment of ocular diseases.

Retinal imaging in premature infants using the Pictor noncontact digital camera

PURPOSE

To evaluate, first, the feasibility of using Pictor, a new portable, noncontact digital fundus camera, to obtain high-quality retinal images of prematurely born infants and, second, the accuracy of grading these images for clinically significant posterior pole vascular changes, that is, pre-plus or plus disease, compared to indirect ophthalmoscopy.

METHODS

Pictor retinal images were obtained on a convenience sample of prematurely born infants during routine examinations for retinopathy of prematurity (ROP). Images were reviewed and graded by two ROP experts, who were masked to demographic and clinical examination findings.

RESULTS

A total of 96 eyes of 48 infants were included. The mean field of view was 5.0 × 6.1 disk diameters (DD). Grader 1 found quality to be fair or good in 96% of images; grader 2 in 97% of images. Grader 1 judged images as having at least 1 DD length of a major vessel in 3 or 4 quadrants in 80% of images; grader 2 in 86% of images. The sensitivity and specificity of grading pre-plus or plus disease on Pictor images was 100% and 79%, respectively, for grader 1, and 83% and 85%, respectively, for grader 2, compared to the reference standard of indirect ophthalmoscopy.

CONCLUSIONS

The Pictor fundus camera can capture digital retinal images of prematurely born infants that have quality sufficient for accurate expert grading in comparison to clinical examination. Pictor shows promise as an ROP screening tool.