Telemedicine approach to screening for severe retinopathy of prematurity: a pilot study

Plus disease diagnosis in retinopathy of prematurity: vascular tortuosity as a function of distance from optic disk

PURPOSE

To examine vascular tortuosity as a function of distance from the optic disk in infants with retinopathy of prematurity.

METHODS

Thirty-four wide-angle retinal images from infants with retinopathy of prematurity were reviewed by 22 experts. A reference standard for each image was defined as the diagnosis (plus vs. not plus) given by the majority of experts. Tortuosity, defined as vessel length divided by straight line distance between vessel end points, was calculated as a function of distance from the disk margin for arteries and veins using computer-based methods developed by the authors.

RESULTS

Mean cumulative tortuosity increased with distance from the disk margin, both in 13 images with plus disease (P = 0.007 for arterial tortuosity [n = 62 arteries], P < 0.001 for venous tortuosity [n = 58 veins] based on slope of best fit line by regression), and in 21 images without plus disease (P < 0.001 for arterial tortuosity [n = 94 arteries], P <0 .001 for venous tortuosity [n = 85 veins]). Images with plus disease had significantly higher vascular tortuosity than images without plus disease (P < 0.05), up to 7.0 disk diameters from the optic disk margin.

CONCLUSION

Vascular tortuosity was higher peripherally than centrally, both in images with and without plus disease, suggesting that peripheral retinal features may be relevant for retinopathy of prematurity diagnosis.

Stanford University Network for Diagnosis of Retinopathy of Prematurity (SUNDROP): five years of screening with telemedicine

BACKGROUND AND OBJECTIVE

To report the 5-year results of the Stanford University Network for Diagnosis of Retinopathy of Prematurity (SUNDROP) telemedicine initiative.

PATIENTS AND METHODS

Infants requiring retinopathy of prematurity (ROP) screening at six neonatal intensive care units from December 1, 2005, to November 30, 2010, were evaluated with remote retinal photography by an ROP specialist. Every infant received outpatient binocular indirect ophthalmoscope examinations until termination criteria were achieved or until treatment. Outcomes were treatment-warranted ROP (TW-ROP, ETROP type 1) and adverse anatomical events.

RESULTS

Five hundred eleven infants (1,022 eyes) were screened. Fifteen infants had TW-ROP and underwent laser photocoagulation. The TW-ROP cohort had significantly lower birth weight and gestational age (both P < .001). No patient progressed to adverse anatomical outcomes and no case of TW-ROP was missed. Tele-medicine had 100% sensitivity, 99.8% specificity, 93.8% positive predictive value, and 100% negative predictive value for detection of TW-ROP.

CONCLUSION

Telemedicine demonstrates high diagnostic accuracy for detection of TW-ROP and can complement ROP screening.

The KIDROP model of combining strategies for providing retinopathy of prematurity screening in underserved areas in India using wide-field imaging, tele-medicine, non-physician graders and smart phone reporting

AIM

To report the Karnataka Internet Assisted Diagnosis of Retinopathy of Prematurity (KIDROP) program for retinopathy of prematurity (ROP) screening in underserved rural areas using an indigenously developed tele-ROP model.

MATERIALS AND METHODS

KIDROP currently provides ROP screening and treatment services in three zones and 81 neonatal units in Karnataka, India. Technicians were trained to use a portable Retcam Shuttle (Clarity, USA) and validated against ROP experts performing indirect ophthalmoscopy. An indigenously developed 20-point score (STAT score) graded their ability (Level I to III) to image and decide follow-up based on a three-way algorithm. Images were also uploaded on a secure tele-ROP platform and accessed and reported by remote experts on their smart phones (iPhone, Apple).

RESULTS

6339 imaging sessions of 1601 infants were analyzed. A level III technician agreed with 94.3% of all expert decisions. The sensitivity, specificity, positive predictive value and negative predictive value for treatment grade disease were 95.7, 93.2, 81.5 and 98.6 respectively. The kappa for technicians to decide discharge of babies was 0.94 (P < 0.001). Only 0.4% of infants needing treatment were missed.The kappa agreement of experts reporting on the iPhone vs. Retcam for treatment requiring and mild ROP were 0.96 and 0.94 (P < 0.001) respectively.

CONCLUSIONS

This is the first and largest real-world program to employ accredited non-physicians to grade and report ROP. The KIDROP tele-ROP model demonstrates that ROP services can be delivered to the outreach despite lack of specialists and may be useful in other middle-income countries with similar demographics.

Plus disease in retinopathy of prematurity: qualitative analysis of diagnostic process by experts

IMPORTANCE

Plus disease is the most important parameter that characterizes severe treatment-requiring retinopathy of prematurity, yet diagnostic agreement among experts is imperfect and the precise factors involved in clinical diagnosis are unclear. This study is designed to address these gaps in knowledge by analyzing cognitive aspects of the plus disease diagnostic process by experts.

OBJECTIVE

To examine the diagnostic reasoning process of experts for plus disease in retinopathy of prematurity using qualitative research techniques.

DESIGN

Cognitive walk-through, with qualitative analysis of videotaped expert responses and quantitative analysis of expert diagnoses.

SETTING

Experimental setting in which experts were videotaped while reviewing study data.

PARTICIPANTS

A panel of international retinopathy of prematurity experts who had the experience of using qualitative retinal features as their primary basis for clinical diagnosis.

INTERVENTION

Six experts were video recorded while independently reviewing 7 wide-angle retinal images from infants with retinopathy of prematurity. Experts were asked to explain their diagnostic process in detail (think-aloud protocol), mark findings relevant to their reasoning, and diagnose each image (plus vs pre-plus vs neither). Subsequently, each expert viewed the images again while being asked to examine arteries and veins in isolation and answer specific questions. Video recordings were transcribed and reviewed. Diagnostic process of experts was analyzed using a published cognitive model.

MAIN OUTCOME AND MEASURES

Interexpert and intraexpert agreement.

RESULTS

Based on the think-aloud protocol, 5 of 6 experts agreed on the same diagnosis in 3 study images and 3 of 6 experts agreed in 3 images. When experts were asked to rank images in order of severity, the mean correlation coefficient between pairs of experts was 0.33 (range, -0.04 to 0.75). All experts considered arterial tortuosity and venous dilation while reviewing each image. Some considered venous tortuosity, arterial dilation, peripheral retinal features, and other factors. When experts were asked to rereview images to diagnose plus disease based strictly on definitions of sufficient arterial tortuosity and venous dilation, all but 1 expert changed their diagnosis compared with the think-aloud protocol.

CONCLUSIONS AND RELEVANCE

Diagnostic consistency in plus disease is imperfect. Experts differ in their reasoning process, retinal features that they focus on, and interpretations of the same features. Understanding these factors may improve diagnosis and education. Future research defining more precise diagnostic criteria may be warranted.

Telemedicine for retinopathy of prematurity

PURPOSE OF REVIEW

To examine and review digital retinal imaging via telemedicine as an important screening and diagnostic tool in the management of retinopathy of prematurity (ROP).

RECENT FINDINGS

The use of wide-angle digital retinal photography to detect clinically significant ROP has been described in numerous reports since 2000. Comparisons with the gold standard of binocular indirect ophthalmoscopy have been favorable. Digital image capture can provide more objective information for disease detection, thereby facilitating internet consultation and retrospective analysis as part of the electronic medical record. As the presence of plus disease in ROP is now the most important criteria for determining the need for laser treatment, computer-based image analysis can potentially provide additional benefit to digital retinal imaging. Telemedicine screening also allows for the extension of diagnostic expertise to underserved areas in both the developed and third world. The role of telemedicine in ROP education will impact both screening efforts and traditional fellowship training in future years.

SUMMARY

As the worldwide incidence of ROP continues to rise, the use of telemedicine for screening, diagnostic and educational purposes will assume increasing importance in the delivery of healthcare for premature infants.

Specialist Nurse Screening for Retinopathy of Prematurity-A Pilot Study

PURPOSE

To compare the accuracy of retinopathy of prematurity (ROP) screening between nurse specialists and an expert pediatric ophthalmologist.

DESIGN

A comparative case series of ROP screening in a level 2 neonatal intensive care unit setting where there is a higher threshold for accepting very premature or unwell neonates.

METHODS

Trained specialist ROP nurses acquired wide-field digital images, graded ROP, and proposed a follow-up plan. This was compared with the findings by an ROP expert ophthalmologist. Outcomes include sensitivity, specificity, positive predictive value, and negative predictive value of ROP grading by trained ROP nurses.

RESULTS

Mean gestational age was 28.6 weeks, and mean birth weight was 1184 g of the 64 consecutive neonates included. A total 316 eye screens was performed. Image acquisition, grading, and a management plan by the ROP nurse were possible in all screens. In right eyes, the presence of any ROP (stage >0) was 15%. Sensitivity, specificity, positive predictive value, and negative predictive value of ROP grading were 91.7% (95% CI, 73%-99%), 80.6% (95% CI, 72.9%-86.9%), 45.8% (95% CI, 31.4%-60.80%), and 98.2% (95% CI, 93.6%-99.8%), respectively. Agreement on the management plan occurred in 84.8% of cases. In virtually all circumstances of disagreement, ROP nurses exaggerated the ROP grading present and/or recommended a repeat screen when discharge from service was more appropriate.

CONCLUSIONS

Our preliminary findings demonstrated good agreement between ROP nurses and the ROP expert ophthalmologist. Further research in expanding the role of utilizing nonphysician health workers in ROP screening is suggested.

The challenge of screening for retinopathy of prematurity

Screening for retinopathy of prematurity (ROP) and the optimum treatment of sight-threatening disease requires detailed understanding of the infants at risk and timely identification. Despite a plethora of guidelines, not all populations and situations are adequately covered, so that what should be preventable visual disability still occurs. This article considers the design of screening guidelines and the possibility of a global guideline, although in certain parts of the world manpower for ROP screening is not available. Algorithms linked to the increase in weight of preterm infants over time may refine the number of babies needing to undergo treatment.

Fluorescein angiography and retinal vascular development in premature infants

OBJECTIVE

To investigate the role of fluorescein angiography (FA) in the management of retinopathy of prematurity (ROP) in preterm newborns.

METHODS

An observational case series of 13 extremely low birth weight infants. From September 2009 to March 2010, 13 newborn infants with a gestational age <29 weeks end/or birth weight <1000 g underwent serial fluorescein angiography with RetCam (Clarity, Pleasanton, CA) every 2 weeks. The fluorescein angiograms were examined to optimize the timing of diagnosis of ROP and to investigate development of retinal and choroidal vascularization.

RESULTS

There were no side effects related to FA. Variable features of retinal and choroidal circulation in preterm infants with a high risk of developing ROP were noted. FA allows vessels branching at the junction between vascular and avascular retina (V-Av junction) to be viewed easily and shows the ROP findings that sometimes cannot be seen by indirect ophthalmoscopy. Dye leakage is the most significant sign of progression to severe ROP or the need for surgery in newborn babies with ROP.

CONCLUSIONS

RetCam-assisted intravenous FA is safe and allows a more objective assessment of the ROP stage and zone.

Stanford University Network for Diagnosis of Retinopathy of Prematurity (SUNDROP): four-years of screening with telemedicine

PURPOSE

To report the four-year experience of the Stanford University Network for Diagnosis of Retinopathy of Prematurity (SUNDROP) telemedicine initiative, which was developed to reduce the risk of blindness from retinopathy of prematurity (ROP).

MATERIALS AND METHODS

A retrospective analysis of the SUNDROP archival data between 12/1/2005 and 11/30/2009. A total of 410 consecutively enrolled infants meeting ROP screening criteria had nurse-obtained fundoscopic images evaluated remotely by an ROP specialist. Every infant then received at least one dilated bedside binocular indirect ophthalmoscope (BIO) examination within one week of discharge. All infants were then followed with both telemedicine images and bedside evaluation in clinic according to recommended screening timelines. Primary outcomes were treatment-warranted ROP (TW-ROP), defined as Early Treatment of ROP Type 1, and adverse anatomical outcomes.

RESULTS

The SUNDROP telemedicine screening initiative has not missed any TW-ROP in its four-year evaluation period. A total of 410 infants (820 eyes) were imaged, resulting in 1486 examinations and 18,097 unique images. An average of 12.2 images were obtained per patient. Fourteen infants met TW-ROP criteria on telemedicine examination. After bedside evaluation, 13 infants required laser photocoagulation and one was followed until he spontaneously regressed. Infants with TW-ROP had a significantly lower gestational age (24.9 weeks), birth weight (658.7 grams), and were more likely to be male than the no TW-ROP cohort (all p values <0.00001). Telemedicine had a calculated sensitivity of 100%, specificity of 99.8%, positive predicative value of 92.9% and negative predictive value of 100% for the detection of TW-ROP. No patient progressed to retinal detachment or any adverse anatomical outcome.

CONCLUSIONS

The SUNDROP initiative demonstrated a high degree of diagnostic reliability and was able to capture all infants with TW-ROP. Telemedicine offers a cost-effective, reliable and accurate screening methodology for identifying infants with TW-ROP without sacrificing quality of care.

Use of digital retinal imaging in screening for retinopathy of prematurity

The frequency of premature births is increasing world-wide. This factor, combined with improved survival and revised screening criteria, is resulting in an increased workload in screening for retinopathy of prematurity. Digital retinal imaging is emerging as an important alternative tool for diagnosing retinopathy of prematurity, and its use has even been extended to developing countries. Neonatal nurses and technicians can be trained to use digital imaging devices effectively. This is important in areas that do not have ready access to paediatric ophthalmologists. The ability to transfer images electronically makes it a valuable tool in telemedicine, while the ability to store and retrieve images is also advantageous from a medico-legal perspective. Image analysis software can further improve the accuracy of diagnosis. The main limitation of this technology is its high capital cost.

Pain and stress assessment after retinopathy of prematurity screening examination: indirect ophthalmoscopy versus digital retinal imaging

BACKGROUND

Increasingly, neonatal clinics seek to minimize painful experiences and stress for premature infants. Fundoscopy performed with a binocular indirect ophthalmoscope is the reference examination technique for screening of retinopathy of prematurity (ROP), and it is associated with pain and stress. Wide-field digital retinal imaging is a recent technique that should be evaluated for minimizing infant pain and stress.

METHODS

The purpose of the study was to assess and compare the impact of using a binocular indirect ophthalmoscope (BIO), or wide-field digital retinal imaging (WFDRI) on pain and stress in infants undergoing ROP screening examination. This was a comparative evaluation study of two screening procedures. Ophthalmologic examinations (N = 70) were performed on 24 infants with both BIO and WFDRI. Pain assessments were performed with two specific neonatal scales (Crying, requires oxygen, increased vital signs, expression and sleeplessness, CRIES and, Premature infant pain profile, PIPP) just prior to the examination, and 30 seconds, 1 hour, and 24 hours later after ending the examination.

RESULTS

Changes over time were significantly different between BIO and WFDRI with both scales (PIPP score, p = .007, and CRIES score, p = .001). Median PIPP score (interquartile interval) at baseline was 4 (3-5). At 30 seconds the score was 8 (6-9) for BIO and 6 (5-7) for WFDRI, respectively. The increase in PIPP score between baseline and 30 seconds was significantly lower with WFDRI (p = .006). The median increase in CRIES score from baseline to 30 seconds was 1 point lower for WFDRI than for BIO (p < .001). No significant difference in response remained at 1 hour or 24 hour assessments.

CONCLUSIONS

A transient short-term pain and stress response occurs with both BIO and WFDRI. Infants examined for screening of ROP with digital retinal imaging present less pain and stress at 30 seconds following completion of the exam when compared with binocular indirect ophthalmoscopy.

Plus disease in retinopathy of prematurity: diagnostic impact of field of view

PURPOSE

To examine the impact of retinal field of view and magnification on interexpert reliability of plus disease diagnosis in retinopathy of prematurity.

METHODS

Fifteen wide-angle images from infants with retinopathy of prematurity were cropped and adjusted in magnification to create 2 additional image categories: medium angle (40°-50°) and narrow angle (20°-30°). These 45 images were uploaded to a Web-based system and interpreted independently by 13 experts of retinopathy of prematurity using a 3-level (plus, preplus, neither) and 2-level (plus, not plus) classification. Absolute agreement and kappa statistics were calculated to compare interexpert reliability.

RESULTS

In the 3-level classification, ≥ 70% experts agreed on the same diagnosis in 8 of the 15 wide-angle images (53%), but only in 3 of the 15 medium-angle (20%) and 3 of the 15 narrow-angle (20%) images. In the 2-level classification, ≥ 80% experts agreed on the same diagnosis in 11 of the 15 wide-angle images (73%), but only in 9 of the 15 medium-angle (60%) and 3 of the 15 narrow-angle (20%) images. Mean kappa of each expert compared with all other experts was 0.40 to 0.59 in 8 of 13 experts (62%) using wide-angle images, was 0 to 0.19 in 7 of 13 experts (54%) using medium-angle images, and was 0.20 to 0.39 in 9 of 13 experts (69%) using narrow-angle images.

CONCLUSION

Interexpert agreement in plus disease diagnosis in wide-angle images is higher than from medium-angle and narrow-angle images. Plus disease is defined using a narrow-angle standard published photograph, yet this study suggests that peripheral findings also contribute to diagnosis.

Telemedicine detection of type 1 ROP in a distant neonatal intensive care unit

PURPOSE

To demonstrate the feasibility of telemedicine screening for retinopathy of prematurity (ROP) by summarizing the results of our experience screening premature infants at a distant hospital in a rural location.

METHODS

Records of all premature infants remotely screened for ROP at a neonatal intensive care unit in Great Falls, Montana, from January 1, 2007 to June 30, 2011, were retrospectively reviewed. The RetCam II imaging system was used to capture retinal images, which were posted on a secure server for evaluation by one of two pediatric ophthalmologists. Infants suspected of having ROP approaching the criteria for laser treatment were transferred to a hospital, where a diagnostic examination was performed and treatment administered when indicated. All other infants received an outpatient diagnostic examination within 2 weeks of discharge.

RESULTS

A total of 582 telemedicine examinations were performed on 137 infants during the study period. Of 13 infants transferred for referral-warranted ROP, 9 ultimately required laser treatment. Good outcomes were noted in all cases, with none progressing to stage 4 or 5 ROP.

CONCLUSIONS

Telemedicine ROP screening detected patients at a remote site in need of laser treatment, allowing prompt transfer with no poor outcomes over a 4.5-year period. Our experience demonstrates the utility of remote screening for ROP.

Detection of clinically significant retinopathy of prematurity using wide-angle digital retinal photography: a report by the American Academy of Ophthalmology

OBJECTIVE

To evaluate the accuracy of detecting clinically significant retinopathy of prematurity (ROP) using wide-angle digital retinal photography.

METHODS

Literature searches of PubMed and the Cochrane Library databases were conducted last on December 7, 2010, and yielded 414 unique citations. The authors assessed these 414 citations and marked 82 that potentially met the inclusion criteria. These 82 studies were reviewed in full text; 28 studies met inclusion criteria. The authors extracted from these studies information about study design, interventions, outcomes, and study quality. After data abstraction, 18 were excluded for study deficiencies or because they were superseded by a more recent publication. The methodologist reviewed the remaining 10 studies and assigned ratings of evidence quality; 7 studies were rated level I evidence and 3 studies were rated level III evidence.

RESULTS

There is level I evidence from ≥5 studies demonstrating that digital retinal photography has high accuracy for detection of clinically significant ROP. Level III studies have reported high accuracy, without any detectable complications, from real-world operational programs intended to detect clinically significant ROP through remote site interpretation of wide-angle retinal photographs.

CONCLUSIONS

Wide-angle digital retinal photography has the potential to complement standard ROP care. It may provide advantages through objective documentation of clinical examination findings, improved recognition of disease progression by comparing previous photographs, and the creation of image libraries for education and research.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Evaluation of vascular disease progression in retinopathy of prematurity using static and dynamic retinal images

PURPOSE

To measure accuracy and speed for detection of vascular progression in retinopathy of prematurity (ROP) from serial images. Two strategies are compared: static side-by-side presentation and dynamic flickering of superimposed image pairs.

DESIGN

Prospective comparative study.

METHODS

Fifteen de-identified, wide-angle retinal image pairs were taken from infants who eventually developed plus disease. Image pairs representing vascular disease progression were taken ≥1 week apart, and control images without progression were taken on the same day. Dynamic flickering pairs were created by digital image registration. Ten experts independently reviewed each image pair on a secure website using both strategies, and were asked to identify progression or state that images were identical. Accuracy and speed were measured, using examination date and ophthalmoscopic findings as a reference standard.

RESULTS

Using static images, experts were accurate in a mean (%) ± standard deviation (SD) of 11.4 of 15 (76%) ± 1.7 image pairs. Using dynamic flickering images, experts were accurate in a mean (%) ± SD of 11.3 of 15 (75%) ± 1.7 image pairs. There was no significant difference in accuracy between these strategies (P = .420). Diagnostic speed was faster using dynamic flickering (24.7 ± 8.3 seconds) vs static side-by-side images (40.3 ± 18.3 seconds) (P = .002). Experts reported higher confidence when interpreting dynamic flickering images (P = .001).

CONCLUSIONS

Retinal imaging provides objective documentation of vascular appearance, with potentially improved ability to recognize ROP progression compared to standard ophthalmoscopy. Speed of identifying vascular progression was faster by review of dynamic flickering image pairs than by static side-by-side images, although there was no difference in accuracy.

Computer-based image analysis for plus disease diagnosis in retinopathy of prematurity

Presence of plus disease in retinopathy of prematurity (ROP) is an important criterion for identifying ROP requiring treatment. Plus disease is defined by a standard published photograph selected more than 20 years ago by expert consensus. However, diagnosis of plus disease has been shown to be subjective and qualitative. Computer-based image analysis using quantitative methods has potential to improve the objectivity of plus disease diagnosis. The objective was to review the published literature involving computer-based image analysis for ROP diagnosis. The PubMed and Cochrane library databases were searched for the keywords "retinopathy of prematurity" AND "image analysis" AND/OR "plus disease." Reference lists of retrieved articles were searched to identify additional relevant studies. All relevant English-language studies were reviewed. There are four main computer-based systems-ROPtool (area under the receiver operating characteristic curve [AUROC], plus tortuosity 0.95, plus dilation 0.87), RISA (AUROC, arteriolar TI 0.71, venular diameter 0.82), Vessel Map (AUROC, arteriolar dilation 0.75, venular dilation 0.96), and CAIAR (AUROC, arteriole tortuosity 0.92, venular dilation 0.91)-attempting to objectively analyze vessel tortuosity and dilation in plus disease in ROP. Some show promise for identification of plus disease using quantitative methods. This has potential to improve the diagnosis of plus disease and may contribute to the management of ROP using both traditional binocular indirect ophthalmoscopy and image-based telemedicine approaches.

Laser treatment for retinopathy of prematurity

Retinal development involves a complex coordination of events that may be affected by premature delivery, leading to retinopathy of prematurity (ROP), a potential blinding childhood disease. The avascular retina drives further disease progression, with laser ablation reducing unfavorable anatomic outcomes as well as maintaining visual acuity. Trials have stressed the importance of early identification and treatment of threshold and high-risk prethreshold disease to improve outcomes. Retinal ablation with laser photocoagulation should involve entire treatment of avascular retina with a confluent laser spot density, avoiding skip lesions. The current review highlights the use of laser photocoagulation in the treatment of ROP.

Plus Disease: Why is it Important in Retinopathy of Prematurity?

Retinopathy of prematurity (ROP) is one of the leading causes of preventable blindness in childhood. Early posterior pole vascular signs of severe ROP have been studied since the first description of the disease. The progressive changes that take place in the posterior pole vessels of an extremely premature baby occur in a predictable fashion soon after birth. These vascular changes are described as plus disease and are defined as abnormal dilation and tortousity of the blood vessels during ROP that may go on to total retinal detachment. The ophthalmological community now has a better understanding of the pathology and cascade of events taking place in the posterior pole of an eye with active ROP. Despite many years of scientific work on plus disease, there continue to be many challenges in defining the severity and quantification of the vascular changes. It is believed that understanding of the vascular phenomenons in patients with ROP will help in designing new treatment strategies that will help in salvaging many of the eyes with severe ROP.

Efficacy of wide-field digital retinal imaging for retinopathy of prematurity screening

BACKGROUND

To evaluate the efficacy of wide-field digital retinal imaging for retinopathy of prematurity screening.

DESIGN

Retrospective study in a quaternary public neonatal intensive care unit.

PARTICIPANTS

A total of 108 premature infants screened for retinopathy of prematurity.

METHODS

Retrospective chart and photo review were performed on participants screened by both serial wide-field digital retinal imaging and concurrent binocular indirect ophthalmoscopy. Review of captured digital photos was performed independently by a masked reader. Using the binocular indirect ophthalmoscopy findings as the gold standard, the efficacy of wide-field digital retinal imaging in detecting treatment-requiring retinopathy of prematurity, defined as type 1 prethreshold disease, was determined.

MAIN OUTCOME MEASURES

Sensitivity and specificity of wide-field digital retinal imaging in detecting treatment-requiring retinopathy of prematurity.

RESULTS

Treatment-requiring retinopathy of prematurity was detected in 11 infants by both binocular indirect ophthalmoscopy examination and telemedicine images taken at the same visit. Wide-field digital retinal imaging has a sensitivity of 100% (95% CI: 76.2-100%) and a specificity of 97.9% (95% CI: 93.4-99.7%) in detecting infants with treatment-requiring retinopathy of prematurity. Positive and negative predictive values of wide-field digital retinal imaging were 84.6% (95% CI: 57.8-97.3%) and 100% (95% CI: 96.9-100%), respectively.

CONCLUSIONS

Wide-field digital retinal imaging is accurate, reliable and efficient in detecting treatment-requiring retinopathy of prematurity. Incorporating wide-field digital retinal imaging with telemedicine in standard retinopathy of prematurity management can potentially improve delivery, accessibility, quality and cost of retinopathy of prematurity care.

Stanford University network for diagnosis of retinopathy of prematurity (SUNDROP): 36-month experience with telemedicine screening

BACKGROUND AND OBJECTIVE

to report the 36-month experience of the Stanford University Network for Diagnosis of Retinopathy of Prematurity (SUNDROP) telemedicine initiative.

PATIENTS AND METHODS

retrospective analysis of the SUNDROP archival data between December 1, 2005, and November 30, 2008, to evaluate this diagnostic technology for retinopathy of prematurity (ROP) screening. A total of 230 consecutively enrolled infants meeting ROP examination criteria were screened with the Ret-Cam II (Clarity Medical Systems, Pleasanton, CA) and evaluated by the SUNDROP reading center at Stanford University. Outcomes included referral-warranted ROP, treatment-warranted ROP, and anatomic outcomes.

RESULTS

in the initial 36-month period, the SUNDROP telemedicine initiative did not miss any treatment-warranted ROP. A total of 230 infants (460 eyes) were imaged, resulting in 1,059 examinations and 10,921 unique images. Ten infants were identified with referral-warranted ROP: nine underwent laser photocoagulation and one regressed spontaneously. The sensitivity was 100% with a specificity of 99.5%. No patient progressed to retinal detachment or other adverse outcomes.

CONCLUSION

the SUNDROP telemedicine screening initiative for ROP has demonstrated high reliability for identification of treatment-warranted disease. All cases of treatment-warranted disease were captured. There were no adverse outcomes.

Detection of the optic nerve head in fundus images of the retina using the Hough transform for circles

Detection of the optic nerve head (ONH) is a key preprocessing component in algorithms for the automatic extraction of the anatomical structures of the retina. We propose a method to automatically locate the ONH in fundus images of the retina. The method includes edge detection using the Sobel operators and detection of circles using the Hough transform. The Hough transform assists in the detection of the center and radius of a circle that approximates the margin of the ONH. Forty images of the retina from the Digital Retinal Images for Vessel Extraction (DRIVE) dataset were used to test the performance of the proposed method. The center and boundary of the ONH were independently marked by an ophthalmologist for evaluation. Free-response receiver operating characteristics (FROC) analysis as well as measures of distance and overlap were used to evaluate the performance of the proposed method. The centers of the ONH were detected with an average distance of 0.36 mm to the corresponding centers marked by the ophthalmologist; the detected circles had an average overlap of 0.73 with the boundaries of the ONH drawn by the ophthalmologist. FROC analysis indicated a sensitivity of detection of 92.5% at 8.9 false-positives per image. With an intensity-based criterion for the selection of the circle and a limit of 40 pixels (0.8 mm) on the distance between the center of the detected circle and the manually identified center of the ONH, a successful detection rate of 90% was obtained with the DRIVE dataset.

Treatment of type 1 retinopathy of prematurity with intravitreal bevacizumab (Avastin)

PURPOSE

The purpose of this study was to report a noncomparative consecutive case series of eyes with type 1 retinopathy of prematurity treated only with intravitreal bevacizumab (Avastin).

METHODS

Twelve consecutive eyes of 7 premature infants, with type 1 retinopathy of prematurity as stated in the Results of the Early Treatment for Retinopathy of Prematurity Randomized Trial, were treated with only one intravitreal injection of bevacizumab (0.625 mg). RetCam pictures were used to document the cases.

RESULTS

Nine eyes had zone I and 3 eyes had zone II retinopathy of prematurity. The infants weighed between 600 and 1,100 grams (mean, 846.57 g). The gestational age ranged from 23 weeks to 28 weeks (mean, 25.57 weeks). All eyes showed regression of the disease with no additional treatment needed.

CONCLUSION

Intravitreal bevacizumab is a useful therapy for type 1 retinopathy of prematurity. However, additional studies are needed to define the role of Avastin as the first-line therapy, in combination, or after the failure of laser photocoagulation.

Stanford University Network for Diagnosis of Retinopathy of Prematurity (SUNDROP): 24-month experience with telemedicine screening

PURPOSE

To report the 24-month experience of the Stanford University Network for Diagnosis of Retinopathy of Prematurity (SUNDROP) telemedicine initiative.

METHODS

Retrospective analysis of the SUNDROP archival data gathered between 1 December 2005 and 30 November 2007 to evaluate this diagnostic technology for ROP screening. One hundred and sixty consecutively enrolled infants meeting ROP examination criteria were screened with the RetCam II and evaluated by the SUNDROP reading centre at Stanford University. Nurses obtained five or six images in each eye. All patients also received a dilated examination within 1 week of discharge. Outcomes included treatment-warranted retinopathy of prematurity (TW-ROP) and anatomical outcomes.

RESULTS

In the initial 24-month period, the SUNDROP telemedicine initiative has not missed any TW-ROP. A total of 160 infants (320 eyes) were imaged, resulting in 669 exams and 7556 images. Seven infants were identified with TW-ROP; six underwent laser photocoagulation and one regressed spontaneously. The sensitivity was 100%, with specificity of 99.4%. No patient progressed to retinal detachment or other adverse outcomes.

CONCLUSION

The SUNDROP telemedicine screening initiative for ROP has been proven to have a high degree of sensitivity and specificity for the identification of treatment-warranted disease. All cases of treatment-warranted disease were captured. There were no adverse outcomes.

Detection of the optic nerve head in fundus images of the retina with Gabor filters and phase portrait analysis

We propose a method using Gabor filters and phase portraits to automatically locate the optic nerve head (ONH) in fundus images of the retina. Because the center of the ONH is at or near the focal point of convergence of the retinal vessels, the method includes detection of the vessels using Gabor filters, detection of peaks in the node map obtained via phase portrait analysis, and an intensity-based condition. The method was tested on 40 images from the Digital Retinal Images for Vessel Extraction (DRIVE) database and 81 images from the Structured Analysis of the Retina (STARE) database. An ophthalmologist independently marked the center of the ONH for evaluation of the results. The evaluation of the results includes free-response receiver operating characteristics (FROC) and a measure of distance between the manually marked and detected centers. With the DRIVE database, the centers of the ONH were detected with an average distance of 0.36 mm (18 pixels) to the corresponding centers marked by the ophthalmologist. FROC analysis indicated a sensitivity of 100% at 2.7 false positives per image. With the STARE database, FROC analysis indicated a sensitivity of 88.9% at 4.6 false positives per image.

Parental perceptions toward digital imaging and telemedicine for retinopathy of prematurity management

BACKGROUND

Telemedicine is an emerging technology with potential to improve care for retinopathy of prematurity (ROP). This study evaluates parental perceptions about digital imaging and telemedicine for ROP care.

METHODS

During a 1-year period, one parent of each infant who underwent wide-field retinal imaging for ROP was given a questionnaire designed to evaluate parental perceptions using a 5-point Likert-type scale. Five items assessed perceptions toward digital retinal imaging, and ten items assessed attitudes toward telemedicine. Construct validity of the questionnaire was examined using factor analysis. Responses were summarized using descriptive and correlational statistics.

RESULTS

Forty-two parents participated. Factor analysis extracted two factors explaining 79% of the total variance in digital retinal imaging items (Cronbach's alpha = 0.843), and three factors explaining 63% of the total variance in telemedicine items (Cronbach's alpha = 0.631). Among digital imaging items, the highest mean (+/-SD) score was for "digital pictures of my child's retinopathy should be included in the permanent medical record" (4.4 +/- 0.6), and the lowest was for "digital cameras and computers are reliable" (3.8 +/- 0.8). Among telemedicine items, the highest mean (+/-SD) score was for "technology will improve the quality of medical care for my child" (4.3 +/- 0.6), and the lowest was for "technology will make it harder for a patient and doctor to establish a good relationship" (2.6 +/- 1.1).

CONCLUSIONS

Parents reported positive perceptions about telemedical ROP diagnosis, but expressed some preference for face-to-face care. Telemedicine has potential to alter the nature of the patient-physician relationship.

Telemedicine for retinopathy of prematurity diagnosis: evaluation and challenges

Retinopathy of prematurity (ROP) is a vasoproliferative disorder affecting low birth weight infants. Although timely diagnosis and treatment can significantly reduce the risk of severe complications, ROP remains a leading cause of childhood blindness worldwide. Limitations of current disease management strategies include extensive travel and logistical coordination requirements for ophthalmologists and neonatologists, decreasing availability of adequately trained ophthalmologists at the point of care, variability in how retinal findings are diagnosed and documented, and a growing need for ROP care worldwide. Store-and-forward telemedicine is an emerging technology by which medical data are captured for subsequent interpretation by a remote expert. This has potential to improve accessibility, quality, and cost of ROP management. In this article, we summarize the current evaluation data on applications of telemedicine for ROP, particularly involving the diagnostic accuracy and reliability of remote image interpretation by experts. We also address challenges such as the cost-effectiveness of telemedicine, and highlight potential barriers to implementation of these systems. Understanding these principles is essential to determine future directions in research and development of telemedicine systems for ROP, as well as for other ophthalmic diseases.

Speed of telemedicine vs ophthalmoscopy for retinopathy of prematurity diagnosis

PURPOSE

To compare the speed of retinopathy of prematurity (ROP) diagnosis using standard indirect ophthalmoscopy with that of telemedicine.

DESIGN

Prospective, comparative study.

METHODS

Three study examiners (2 pediatric retinal specialists [R.V.P.C., T.C.L.] and 1 pediatric ophthalmologist [M.F.C.]) conducted ROP diagnosis via standard indirect ophthalmoscopy and telemedicine. Each examiner performed: 1) standard ophthalmoscopy on 72 to 150 consecutive infants at his respective institution and 2) telemedical diagnosis on 125 consecutive deidentified retinal image sets from infants from an at-risk population. Time for ophthalmoscopic diagnosis was measured in 2 ways: 1) time spent by the examiner at the infant's bedside and 2) mean total time commitment per infant. Time for telemedicine diagnosis was recorded by computer time stamps in the web-based system. For each examiner, nonparametric statistical analysis (Mann-Whitney U test) was used to compare the distribution of times for examination by ophthalmoscopy vs telemedicine.

RESULTS

Mean (+/- standard deviation [SD]) times for ophthalmoscopic diagnosis ranged from 4.17 (+/- 1.34) minutes to 6.63 (+/- 2.28) minutes per infant. Mean (+/- SD) times for telemedicine diagnosis ranged from 1.02 (+/- 0.27) minutes to 1.75 (+/- 0.80) minutes per infant. Telemedicine was significantly faster than ophthalmoscopy (P < .0001). The total time commitment by ophthalmologists performing bedside ophthalmoscopy for ROP diagnosis, including travel and communication with families and hospital staff, was 10.08 (+/- 2.53) minutes to 14.42 (+/- 2.64) minutes per infant.

CONCLUSIONS

The ophthalmologist time requirement for telemedical ROP diagnosis is significantly less than that for ophthalmoscopic diagnosis. Additional time requirements associated with bedside ROP diagnosis increased this disparity. Telemedicine has potential to alleviate the time commitment for ophthalmologists who manage ROP.

Digital image analysis of plus disease in retinopathy of prematurity

An accurate assessment of retinopathy of prematurity (ROP) is essential in ensuring correct and timely treatment of this potentially blinding condition. Current modes of assessment are based upon clinical grading by expert examination of retinal changes. However, this may be subjective, unreliable and difficult and there has been significant interest in alternative means of measurement. These have been made possible through technological advancements in image capture and analysis as well as progress in clinical research, highlighting the specific importance of plus disease in ROP. Progress in these two fields has highlighted the potential for digital image analysis of plus disease to be used as an objective, reliable and valid measurement of ROP. The potential for clinical and scientific advancement through this method is argued and demonstrated in this article. Along with the potential benefits, there are significant challenges such as in image capture, segmentation, measurement of vessel width and tortuosity; these are also addressed. After discussing and explaining the challenges involved, the research articles addressing digital image analysis of ROP are critically reviewed. Benefits and limitations of the currently published techniques for digital ROP assessment are discussed with particular reference to the validity and reliability of outcome measures. Finally, the general limitations of current methods of analysis are discussed and more diverse potential areas of development are discussed.

Wide-field digital imaging based telemedicine for screening for acute retinopathy of prematurity (ROP). Six-year results of a multicentre field study

Objective

To report on a 6-year experience with wide-field digital imaging based telemedicine (WFDI telemedicine) to reduce the risk for blindness from retinopathy of prematurity (ROP).

Methods

Wide-angle digital fundus cameras (RetCam 120, Massie Lab, Pleasanton, CA, USA) were installed in five neonatal intensive care units (NICUs) in Germany. All prematures at risk were screened with WFDI, and the local ophthalmologists were asked to continue binocular indirect ophthalmoscopy (BIO) according to the German guidelines. Image data were coded and transferred to the Reading Centre in Regensburg. Image evaluation and additional BIO of infants with suspected treatment-requiring ROP (STR-ROP i.e. threshold ROP zone II, prethreshold ROP zone I (type-1 ROP according to ETROP), and ROP possibly requiring treatment but not reliably classifiable from the images) were performed by paediatric ophthalmologists at the Reading Centre. ROP was classified following ICROP, ETROP, and revised ICROP criteria. Outcome measures were incidence of clinically relevant ROP (CR-ROP, i.e. any ROP up to mid-peripheral zone III, ≤ stage 3+), sensitivity to detect STR-ROP, and positive predictive value to detect treatment-requiring ROP (TR-ROP).

Results

In total, 1,222 prematures at risk were screened (mean BW 1395 g, SD ±507 g; mean GA 30 wks, SD ±3 wks). The overall incidence of CR-ROP was 27.6% (71.8% mild = stage 1 to 3 without plus disease, 15.7% prethreshold = type-1 ROP according to ETROP, 12.5% threshold according to ICROP). Zone I disease was present in 3.3%, zone II disease in 76.5%, and zone III disease in 20.2%. According to ETROP, 95 infants were type-1 or type-2 ROP; 67.4% type-1 ROP, and 32.6% type-2 ROP. Of all 1,222 infants, 3.5% received treatment. Following ETROP (not applied in the study), 5.3% would have been treated. The sensitivity for detecting STR-ROP was 100%, and the positive predictive value for TR-ROP 82.4% (28/34) at the time of the first referral (28 infants, ≤ stage 3+ in zone I or II).

Conclusion

All TR-ROP was detected in time, showing the potential of our telemedical screening program. The overall incidence of CR-ROP was comparable to ROP incidences reported in other West European countries.

Systematic review of digital imaging screening strategies for retinopathy of prematurity

BACKGROUND

Retinal imaging with remote interpretation could decrease the number of diagnostic eye examinations that premature infants need for the detection of retinopathy of prematurity and thus decrease the time demand on the relatively small pool of ophthalmologists who perform retinopathy of prematurity examinations.

OBJECTIVE

Our goal was to review systematically the evidence regarding the reliability, validity, safety, costs, and benefits of retinal imaging to screen infants who are at risk for retinopathy of prematurity.

METHODS

We searched Medline, the Cochrane library, CINAHL, and the bibliographies of all relevant articles. All English-language studies regardless of design with primary data about our study questions were included. We excluded (1) studies that only included subjects with retinopathy of prematurity, (2) hypothetical models other than cost-effectiveness studies, and (3) validity studies without sufficient data to determine prevalence, sensitivity, and specificity or that only evaluated subjects for 1 component of retinopathy of prematurity (eg, plus disease only).

RESULTS

Studies of only 1 retinal imaging device (RetCam [Clarity Medical Systems, Inc, Pleasanton, CA]) met the inclusion criteria. There was a wide range in reported sensitivity, but specificity was high. There were several important limitations noted, including the eye as the unit of analysis instead of the individual or variations in the criteria for determining a true-positive or true-negative screening result. The risk of retinal hemorrhage resulting from imaging is low, and systemic effects (eg, bradycardia, hypertension, decreased oxygen saturation) are mild. No generalizable cost-effectiveness data were found.

CONCLUSIONS

The evidence base is not sufficient to recommend that retinal imaging be routinely adopted by NICUs to identify infants who have serious retinopathy of prematurity.

Stanford University Network for Diagnosis of Retinopathy of Prematurity (SUNDROP): 18-month experience with telemedicine screening

PURPOSE

To report the 18-month experience of the Stanford University Network for Diagnosis of Retinopathy of Prematurity (SUNDROP) telemedicine initiative.

DESIGN

Retrospective analysis of the SUNDROP archival data between 1 December 2005 and 30 May 2007, evaluating this new diagnostic technology for ROP screening.

PARTICIPANTS

All 97 consecutively enrolled infants in the SUNDROP network.

METHODS

All patients were screened using the RetCam II, and evaluated by the SUNDROP reading center at Stanford University. Nurses were trained to obtain five images in each eye. All patients were screened by an ophthalmologist trained in diagnosing ROP within 1 week of discharge from the hospital.

MAIN OUTCOME MEASURES

Outcomes included referral-warranted disease, need for treatment, and anatomic outcomes. Referral-warranted disease was defined as any Early Treatment Retinopathy of Prematurity Disease Type 2 or greater, threshold disease, any plus disease, and any stage 4 or higher disease.

RESULTS

In the initial 18-month period, the SUNDROP telemedicine screening initiative has not missed any referral-warranted disease for ROP. A total of 97 infants (194 eyes) were enrolled, resulting in 443 unique examinations and 4,929 unique images. The mean birth weight of the infants was 1,186.9 grams, with a mean gestational age at birth of 28.9 weeks. Seven infants were identified with referral-warranted disease; six patients underwent laser photocoagulation and completely regressed. The one remaining patient regressed spontaneously, and did not require intervention. Calculated sensitivity and specificity was 100% and 98.9% respectively. No patient progressed to retinal detachment or other adverse outcome. Inadequate exposure, artifact, poor visualization of the periphery, and lack of a complete standardized image set in some patients were identified as areas requiring further assessment.

CONCLUSIONS

The SUNDROP telemedicine screening initiative for ROP has proven to have a high degree of sensitivity and specificity for identification of referral-warranted disease. Training was easily implemented. All cases of referral-warranted disease were captured. There were no adverse outcomes.

Agreement among pediatric ophthalmologists in diagnosing plus and pre-plus disease in retinopathy of prematurity

PURPOSE

Plus disease has become the major criterion for laser treatment in infants with retinopathy of prematurity (ROP), but its assessment is subjective. Our purpose was to compare quadrant-level and eye-level assessment of plus disease and pre-plus disease among 3 experienced ROP examiners and to report their rate of agreement.

METHODS

One hundred eighty-one high-quality RetCam images from premature infants were graded by 3 of the authors. Dilation and tortuosity were judged separately using a scale of normal or sufficiently abnormal to meet criteria for pre-plus or plus disease.

RESULTS

There was disagreement on the presence of plus disease for 18 images (10%), on tortuosity sufficient for plus disease (plus tortuosity) for 26 images (14%), and on dilation sufficient for plus disease (plus dilation) for 26 images (14%). Of 67 images judged to have pre-plus disease or worse, there was disagreement on the presence of plus disease for 18 images (27%), on plus tortuosity for 25 images (37%), and on plus dilation for 21 images (31%). For distinguishing plus or pre-plus disease from normal, there was disagreement on pre-plus tortuosity for 38 of 181 images (21%) and on pre-plus dilation for 58 of 181 images (32%).

CONCLUSIONS

Three experienced ROP examiners disagreed frequently on the diagnosis of plus or pre-plus disease when evaluating cropped clinical photographs of infants, many of which had borderline plus disease. Further study is required to determine the implications of these observations on clinical decision making.

Retinopathy of prematurity management using single-image vs multiple-image telemedicine examinations

PURPOSE

To compare performance of single-image vs multiple-image telemedicine examinations for retinopathy of prematurity (ROP) diagnosis.

DESIGN

Prospective comparative study.

METHODS

A total of 248 eyes from 67 consecutive infants underwent wide-angle retinal imaging by a trained neonatal nurse at 31 to 33 weeks and/or 35 to 37 weeks postmenstrual age (PMA) at a single academic institution. Data were uploaded to a web-based telemedicine system and interpreted by three masked retinal specialists. Diagnoses were provided based on single images, and subsequently on multiple images, from both eyes of each infant. Findings were compared to a reference standard of indirect ophthalmoscopy by a pediatric ophthalmologist. Primary outcome measures were recommended follow-up interval, presence of plus disease, presence of type-2 or worse ROP, and presence of visible peripheral ROP.

RESULTS

Among the three graders, mean sensitivity/specificity for detection of infants requiring follow-up in less than one week were 0.85/0.93 by single-image examination and 0.91/0.88 by multiple-image examination at 35 to 37 weeks PMA. Mean sensitivity/specificity for detection of infants with type-2 or worse ROP were 0.82/0.95 by single-image examination and 1.00/0.91 by multiple-image examination at 35 to 37 weeks PMA. Mean sensitivity/specificity for detection of plus disease were 1.00/0.86 by single-image examination and 1.00/0.87 by multiple-image examination at 35 to 37 weeks PMA. There were no statistically-significant intragrader differences between accuracy of single-image and multiple-image telemedicine examinations for detection of plus disease.

CONCLUSIONS

Single-image and multiple-image telemedicine examinations perform comparably for determination of recommended follow-up interval and detection of plus disease. This may have implications for development of screening protocols, particularly in areas with limited access to ophthalmic care.

Telemedicine screening for retinopathy of prematurity in developing countries using digital retinal images: a feasibility project

PURPOSE

To determine the feasibility in a middle-level human development country of onsite training, image collection, Internet transfer, and remote grading of digital retinal images from babies screened for retinopathy of prematurity (ROP).

METHODS

Two experienced nurses in a neonatal nursery in Lima, Peru, were trained to take posterior pole (30 degrees ) digital retinal images. Nurses obtained posterior pole retinal images from babies undergoing routine ROP screening and selected images for uploading via Internet for remote evaluation by five masked ROP experts. Results of gradings were compared with same-day clinical diagnostic examinations by an experienced ophthalmologist. Success rates for image acquisition and transfer for grading by expert readers were calculated.

RESULTS

Serial image sets from 26 of the 28 babies enrolled in this study were obtained; two babies were too unstable for imaging. Fifty-six of 58 (96.6%) imaging sessions were successful in obtaining retinal images. Three hundred thirty of 336 (98.2%) images obtained were successfully uploaded to an interactive database. Remote graders judged 93.6% to 97.3% of image sets suitable for ROP grading. Preliminary results indicate sensitivities for detection of serious ROP from 45.5% to 95.2% among individual readers, with specificities of 61.7% to 96.2% when images were gradable.

CONCLUSIONS

A telemedicine approach for ROP screening using digital retinal images obtained by nonophthalmologists is feasible in rapidly developing countries that lack ROP-trained ophthalmologists. If remote grading of digital images is validated as an effective method for identifying referral-warranted ROP (RW-ROP), images obtained by nonphysicians may provide a means of identifying babies who require a diagnostic examination by an ophthalmologist.

Telemedical diagnosis of retinopathy of prematurity intraphysician agreement between ophthalmoscopic examination and image-based interpretation

OBJECTIVE

To evaluate the intraphysician agreement between ophthalmoscopic examination and image-based telemedical interpretation for retinopathy of prematurity (ROP) diagnosis, when performed by the same expert physician grader.

DESIGN

Prospective, nonrandomized, comparative study.

PARTICIPANTS

Sixty-seven consecutive premature infants who underwent ROP examination at a major university medical center whose parents consented for participation.

METHODS

Infants underwent standard dilated ophthalmoscopy by one of two pediatric ophthalmologists, followed by retinal imaging with a commercially available wide-angle fundus camera by a trained neonatal nurse. Study examinations were performed at 31 to 33 weeks postmenstrual age (PMA) and/or 35 to 37 weeks PMA. Images were uploaded to a Web-based telemedicine system developed by the authors. After a 4- to 12-month period, telemedical interpretations were performed in which each physician graded images from infants upon whom he had initially performed ophthalmoscopic examinations. Diagnoses were classified using an ordinal scale: no ROP, mild ROP, type 2 prethreshold ROP, and treatment-requiring ROP.

MAIN OUTCOME MEASURES

Absolute intraphysician agreement and kappa statistic between ophthalmoscopic examination and telemedical interpretation were calculated by eye. All intraphysician discrepancies were reviewed, and underlying causes were classified by eye as no ROP identified by ophthalmoscopic examination, no ROP identified by telemedical interpretation, discrepancy about presence of zone 1 ROP, discrepancy about presence of plus disease, or other discrepancy in classification of ROP stage.

RESULTS

Absolute intraphysician agreement between ophthalmoscopic examination and telemedical interpretation was 86.3%. The kappa statistic for intraphysician agreement between examinations ranged from 0.657 (substantial agreement) for diagnosis of treatment-requiring ROP to 0.854 (near-perfect agreement) for diagnosis of mild or worse ROP. Among 206 eye examinations (103 infant examinations), there were 28 (13.6%) intraphysician discrepancies in diagnosis, 8 of which resulted from uncertainty about presence of zone 1 disease and 4 from uncertainty about presence of plus disease.

CONCLUSIONS

Intraphysician agreement between ophthalmoscopic examination and telemedical interpretation for ROP was very high. Neither examination modality appeared to have a systematic tendency to overdiagnose or underdiagnose ROP. Diagnosis of zone 1 disease and plus disease were major sources of clinically significant discrepancies.

The photographic screening for retinopathy of prematurity study (photo-ROP). Primary outcomes

PURPOSE

To evaluate the utility of remote digital fundus imaging as compared to indirect ophthalmoscopy to screen for retinopathy of prematurity (ROP).

METHODS

This was a prospective, multicenter, masked clinical trial. Infants <31 weeks gestational age and <1000 g at birth were eligible for enrollment. Eligible enrolled infants were screened for ROP employing serial fundus imaging followed by indirect ophthalmoscopy. The main outcome measures were diagnostic sensitivity, specificity, positive and negative predictive values, and accuracy of image interpretation compared to ophthalmoscopy.

RESULTS

Fifty-one infants (102 eyes) meeting eligibility criteria were enrolled between February 2001 and February 2002. Mean weekly examinations per infant (+/-SD) were 5.73 +/- 3.22 (median 7; range 2-10). For the purposes of this study, the reading center established a definition of ROP seen on digital fundus images deemed sufficiently severe (termed clinically significant ROP, or CSROP) to warrant on-site examination by an ophthalmologist experienced in ROP. CSROP developed in 59 of 102 eyes (57.8%; 31 right eyes and 28 left eyes). Of the eyes with CSROP, 22% (13/59; 7 right eyes and 6 left eyes) progressed to ROP severe enough to require treatment according to the criteria of the Early Treatment for ROP Randomized Trial. Using onsite indirect ophthalmoscopic diagnosis as the reference standard, CSROP was identified by digital images with a sensitivity of 92% (94% right eyes and 89% left eyes) and specificity of 37.21% (40% right eyes and 35% left eyes), and Early Treatment for Retinopathy of Prematurity (ETROP) prethreshold Type I with a sensitivity of 92% (86% right eyes and 100% left eyes) and specificity of 67.39% (67% right eyes and 68% left eyes).

CONCLUSIONS

Remote interpretation of digital fundus images is a useful adjunct to conventional bedside ROP screening by indirect ophthalmoscopy. Diagnostic sensitivity in this study was excellent. It was highly unlikely that severe ROP would be missed when image quality was high. Differences between the two screening approaches in timing of diagnosis of CSROP and ETROP were not statistically significant. Remote digital fundus imaging as deployed in this study is unlikely to supplant bedside ophthalmoscopic examination due to limitations in diagnostic sensitivity, specificity, and accuracy when image quality is poor.

Does observer bias contribute to variations in the rate of retinopathy of prematurity between centres?

PURPOSE

We aimed to indirectly assess the contribution from observer bias to between centre variability in the incidence of acute retinopathy of prematurity (ROP).

METHODS

The Australian and New Zealand Neonatal Network (ANZNN) collected data on the highest stage of acute ROP in either eye in 2286 infants born at less than 29 weeks in 1998-1999 and cared for in one of 25 neonatal intensive care units (NICUs). Chi-squared analysis was used to detect differences in the proportion of stages of ROP for each neonatal intensive care unit. These proportions were compared with those reported in two large studies of treatment for ROP.

RESULTS

The incidence of acute ROP in the ANZNN cohort was 42% and the ratio of stage 1:2:3 ROP was 1.5:1.9:1. There was considerable variation in both the incidence of acute ROP and the proportions with stage 1:2:3 ROP between centres. A chi-squared test determined that the assignment of stages 1, 2 and 3/4 ROP was not independent of centre (chi(2)(48) = 165.2; P < 0.0001). Treatment of stage 3 ROP varied between 15% and 120%, indicating some eyes were treated at less than stage 3.

CONCLUSION

The data are highly suggestive of observer bias contributing to the observed between centre variation in the incidence of acute ROP. In neonatal intervention studies where acute ROP is an outcome it would seem important to have an accreditation process for examining ophthalmologists, and there are similar arguments for neonatal networks which collect these data.

Screening for retinopathy of prematurity

The CRYO-ROP study confirmed the success of treatment for ROP and made screening mandatory. National based screening has been influenced by the varied incidence of disease in developed and developing countries. Most ophthalmologists in developed countries screen infants born between 1000 and 1500 g and between 28 and 31 weeks gestation post menstrual age. The 1984 classification has been updated to highlight the importance of plus disease. The ETROP study findings have resulted in earlier treatment and elevated the importance of screening. Measures such as nesting may help to reduce infant distress during examination. It is important for neonatal units to have an agreed policy on screening and both neonatologist and neonatal nurses have an invaluable role. Diagnostic retinal imaging and telemedicine may have an increasing role in future screening. Timely and accurate screening is the most important first step as earlier treatment results in improved visual prognosis.

Application of new ophthalmic technology in the pediatric patient

PURPOSE OF REVIEW

The present review will summarize briefly the recent advances in diagnostic tools, surgical techniques, and ophthalmic medications as they relate to the pediatric patient. The review will highlight results from studies that have investigated these new technologies and techniques.

RECENT FINDINGS

In the past several years there has been a plethora of literature on the application of new technologies and surgical techniques in children. New tools have been used for everything from gathering normative data about the pediatric eye to using the technologies to study diseases such as glaucoma and ocular tumors. Results of surgical techniques such as small-incision cataract surgery, sutureless vitrectomy, and refractive surgery are now reported with regularity in the pediatric ophthalmology literature.

SUMMARY

In the past 10 years pediatric ophthalmology has made significant advances. Technology has enabled us to qualify and quantify disease states more efficiently, and to explore new surgical techniques for disease processes that were formerly considered relatively untreatable.