- Email: [email protected]
ROPtool analysis of images acquired using a noncontact handheld fundus camera (Pictor)—a pilot study
570
Vickers et al
Volume 19 Number 6 / December 2015
RPE atrophy is widespread, often with a mottled or reticulated appearance. Intraretinal pigment migration in the mid to far periphery is typical and often becomes heavier as children get older, at which time it can also occur more centrally. Central macular atrophy occurs in all cases, sometimes with a yellow discoloration. Cycloplegic refraction is often hyperopic. Sometimes paraarteriolar sparing can be appreciated. Although previous reports have confirmed these characteristic features,1-3 the presence or absence or type of strabismus is typically not mentioned. Strabismus is generally nonspecific in childhood retinal dystrophies. In our experience, different horizontal and/ or vertical deviations are common but incomitant vertical deviations are uncommon, even with profound visual loss. Our observation of inability to supraduct in these 4 children with retinal dystrophy who were subsequently confirmed to harbor recessive RDH12 mutations suggests this form of strabismus could be a recurrent finding for a subset of children with this form of retinal dystrophy. It is possible that the finding could be related to the level of visual loss in these children rather than the specific type of retinal dystrophy; however, 1 affected child did have best-corrected visual acuity as good as 20/100 (subject 2). Further studies are needed to better understand how frequently elevation deficiency occurs in RDH12-related retinopathy and potentially in other genetic forms of retinal dystrophy. The main differential diagnosis for elevation deficiency with retinal dystrophy has classically been neurological disease, which is typically acquired and of later onset. Such neurological disease includes KearnsSayre syndrome and related mitochondrial disorders,8 spinocerebellar ataxia,9 and potentially neurodegeneration with brain iron accumulation.10 References 1. Schuster A, Janecke AR, Wilke R, et al. The phenotype of early-onset retinal degeneration in persons with RDH12 mutations. Invest Ophthalmol Vis Sci 2007;48:1824-31. 2. Valverde D, Pereiro I, Vallespin E, Ayuso C, Borrego S, Baiget M. Complexity of phenotype-genotype correlations in Spanish patients with RDH12 mutations. Invest Ophthalmol Vis Sci 2009;50:1065-8. 3. Mackay DS, Dev Borman A, Moradi P, et al. RDH12 retinopathy: novel mutations and phenotypic description. Mol Vis 2011;17:2706-16. 4. Abu-Safieh L, Alrashed M, Anazi S, et al. Autozygome-guided exome sequencing in retinal dystrophy patients reveals pathogenetic mutations and novel candidate disease genes. Genome Res 2013;23: 236-47. 5. Janecke AR, Thompson DA, Utermann G, et al. Mutations in RDH12 encoding a photoreceptor cell retinol dehydrogenase cause childhood-onset severe retinal dystrophy. Nat Genet 2004;36:850-54. 6. Perrault I, Hanein S, Gerber S, et al. Retinal dehydrogenase 12 (RDH12) mutations in Leber congenital amaurosis. Am J Hum Genet 2004;75:639-46. 7. Thompson DA, Janecke AR, Lange J, et al. Retinal degeneration associated with RDH12 mutations results from decreased 11-cis retinal synthesis due to disruption of the visual cycle. Hum Mol Genet 2005;14:3865-75. 8. Gronlund MA, Honarvar AK, Andersson S, et al. Ophthalmological findings in children and young adults with genetically verified mitochondrial disease. Br J Ophthalmol 2010;94:121-7.
9. Aleman TS, Cideciyan AV, Volpe NJ, Stevanin G, Brice A, Jacobson SG. Spinocerebellar ataxia type 7 (SCA7) shows a conerod dystrophy phenotype. Exp Eye Res 2002;74:737-45. 10. Khan AO, AlDrees A, Elmalik SA, et al. Ophthalmic features of PLA2G6-related paediatric neurodegeneration with brain iron accumulation. Br J Ophthalmol 2014;98:889-93.
ROPtool analysis of images acquired using a noncontact handheld fundus camera (Pictor)—a pilot study Laura A. Vickers, MD, Sharon F. Freedman, MD, David K. Wallace, MD, MPH, and S. Grace Prakalapakorn, MD, MPH The presence of plus disease is the primary indication for treatment of retinopathy of prematurity (ROP), but its diagnosis is subjective and prone to error. ROPtool is a semiautomated computer program that quantifies vascular tortuosity and dilation. Pictor is an FDAapproved, noncontact, handheld digital fundus camera. This pilot study evaluated ROPtool’s ability to analyze high-quality Pictor images of premature infants and its accuracy in diagnosing plus disease compared to clinical examination. In our small sample of images, ROPtool could trace and identify the presence of plus disease with high accuracy.
R
etinopathy of prematurity (ROP) is a leading cause of blindness in children in the industrialized world.1 Treatment depends on timely screening and diagnosis, but there are too few ophthalmologists available to screen for ROP worldwide.2 One strategy to overcome this barrier includes an ROP screening system using semiautomated analysis of retinal photographs to identify infants that may need treatment. Prior studies have shown that ROPtool analysis of images captured by RetCam and video indirect ophthalmoscopy (VIO) can diagnose plus disease with high accuracy compared to clinical diagnosis.3-8 The Pictor camera (Volk Optical, Mentor, OH) is considerably less expensive than Retcam and can capture still images of higher quality than VIO. A recent study showed that the Pictor camera can capture retinal
Author affiliations: Duke University Eye Center, Durham, North Carolina Dr. Prakalapakorn is supported by NIH K23EY024268. The funding organization had no role in the design or conduct of this research. Submitted May 6, 2015. Revision accepted July 28, 2015. Correspondence: S. Grace Prakalapakorn, MD, MPH, Assistant Professor of Ophthalmology and Pediatrics, Duke University, DUMC 3802, 2351 Erwin Road, Durham, NC, 27710 (email: [email protected]). J AAPOS 2015;19:570-572. Copyright Ó 2015 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/$36.00 http://dx.doi.org/10.1016/j.jaapos.2015.07.291
Journal of AAPOS
Volume 19 Number 6 / December 2015
Vickers et al
571
images of premature infants with sufficient quality for grading of pre-plus or plus disease by two ROP experts with high sensitivity (79% and 85%) and specificity (100% and 83%).9 The present pilot study evaluates the feasibility and accuracy of analyzing high-quality Pictor images with ROPtool for plus disease.
Methods This pilot study was approved by the Duke Health System Institutional Review Board and complied with regulations of the US Health Insurance Portability and Accountability Act of 1996. A subset of Pictor images graded by two pediatric ophthalmologists experienced in ROP screening (SFF and DKW) for image quality (good, fair, or poor) in a previous study were retrospectively analyzed.9 The images were obtained without a lid speculum during ROP rounds at Duke University Hospital Neonatal Intensive Care Nursery from December 2011 to May 2012. For an infant to be included in the present study, an image of at least one eye had to be considered of fair or good quality by both graders and to have at least one major vessel visible for one disk diameter in length from the optic nerve in all quadrants. For each infant, the best image from one eye based on the above criteria was selected. We used ROPtool v2.1.8 to analyze the Pictor images in random order. An image was “traceable” by ROPtool if all four quadrants were traceable; a quadrant was “traceable” if it contained one vessel at least one disk diameter in length that could be traced by ROPtool. The most tortuous major vessel in each quadrant was traced. Because the diagnosis of plus disease requires sufficient dilation and tortuosity in at least two quadrants, the second most tortuous vessel in each image was analyzed. One of the authors (LAV) performed all ROPtool analysis. Analyses was limited to the ROPtool indices tortuosity and tortuosity weighted plus (TWP), which is a combined measure of dilation and tortuosity that gives more weight to dilation as tortuosity increases.5 Receiver operating characteristic (ROC) curves were calculated to determine the accuracy of ROPtool in assessing the presence of plus or “pre-plus or plus” disease compared to the reference standard clinical examination diagnosis given by one of two ROP experts (SFF and DKW) on the same date the photographs were obtained. All statistical analysis was performed with SAS v.9.1.3 (SAS Institute Inc, Cary, NC).
Results Of the 48 infants included in the previous study, all had fair or good quality images in at least one eye (47 [98%] right eye images and 44 [92%] left eye images), 37 (77%) infants had an image of at least one eye with fair or good quality with one major vessel visible for at least one disk diameter length from the optic nerve in all quadrants. Of these 37 images, 35 (95%) were traceable, that is, had four quadrants traceable by ROPtool. Of the 35 traceable images, 3 (8.6%) had plus and 1 (3%) had pre-plus disease based on the reference standard clinical examination. Using the ROPtool parameters of tortuosity
Journal of AAPOS
FIG 1. Receiver operating characteristic curves for Pictor images using tortuosity and tortuosity weighted plus (TWP) compared to clinical diagnosis of plus disease (A), or “pre-plus or plus” disease (B) as the outcome. AUC, area under the curve.
and TWP, the area under the curve (AUC) of the ROC curve for the diagnosis of plus disease was 0.99 for tortuosity and 0.99 for TWP; for pre-plus or plus disease the AUC was 1.0 for tortuosity and 0.98 for TWP (Figure 1).
Discussion High-quality Pictor images of the retina of premature infants are traceable and can be analyzed using ROPtool
572
Grigorian et al
with high accuracy for diagnosing plus disease. This is the first study showing ROPtool’s ability to accurately analyze images obtained using a handheld, noncontact camera. The ROPtool parameters tortuosity and TWP both show high accuracy for diagnosing plus disease in Pictor images. We considered tortuosity alone as one parameter because previous studies found that ROPtool can accurately measure retinal tortuosity in high-quality RetCam images5,7,10 and tortuosity alone has been shown to be highly correlated with plus disease diagnosis.4 We investigated TWP because as a combined measure, TWP has high accuracy to diagnose plus disease in RetCam images.5 Future studies should investigate how well the ROPtool parameters of tortuosity and TWP perform using lower quality Pictor images. Semiautomated diagnosis of plus disease in ROP using images acquired from a handheld, noncontact camera advances efforts to increase the objectivity, automation, safety, and efficiency of ROP screening. RetCam requires contact with the cornea, and VIO requires an examiner trained in indirect ophthalmoscopy (eg, an ophthalmologist or optometrist). By contrast, a less qualified imager (eg, nonophthalmologist healthcare worker) can capture fundus images using Pictor with less risk for damage to the cornea (eg, corneal abrasion or infection), because no corneal contact is involved. ROPtool analysis of Pictor images could also be carried out by trained non-physician healthcare workers, increasing automation and objectivity in screening while expanding our screening workforce beyond ophthalmologists. As more of the ROP screening process is shown to be safely and accurately carried out by nonophthalmologists, ophthalmologists may focus their efforts on infants requiring treatment. This pilot study is limited by the relatively small number of images and inclusion of only high-quality images. Also, ROPtool depends on user input to define the border of the optic nerve head and center of the macula, which introduces interuser variability in analysis. To address these limitations, future studies should include a larger number of images of varying image quality and multiple ROPtool users to simulate a semiautomated ROP screening process.
Volume 19 Number 6 / December 2015 5. Cabrera MT, Freedman SF, Kiely AE, et al. Combining ROPtool measurements of vascular tortuosity and width to quantify plus disease in retinopathy of prematurity. J AAPOS 2011;15:40-44. 6. Wallace DK, Freedman SF, Zhao Z. A pilot study using ROPtool to measure retinal vascular dilation. Retina 2009;29:1182-7. 7. Kiely AE, Wallace DK, Freedman SF, Zhao Z. Computer-assisted measurement of retinal vascular width and tortuosity in retinopathy of prematurity. Arch Ophthalmol 2010;128:847-52. 8. Cabrera MT, Freedman SF, Hartnett ME, Stinnett SS, Chen BB, Wallace DK. Real-time, computer-assisted quantification of plus disease in retinopathy of prematurity at the bedside. Ophthalmic Surg Lasers Imaging Retina 2014;45:542-8. 9. Prakalapakorn SG, Wallace DK, Freedman SF. Retinal imaging in premature infants using the Pictor noncontact digital camera. J AAPOS 2014;18:321-6. 10. Wallace DK, Freedman SF, Zhao Z. Evolution of plus disease in retinopathy of prematurity: quantification by ROPtool. Trans Am Ophthalmol Soc 2009;107:47-52.
Comparison of the Icare rebound tonometry with the Goldmann applanation tonometry in a pediatric population Florin Grigorian, MD,a A. Paula Grigorian, MD,a Ang Li, AB,b Abdus Sattar, PhD,c Rohit Krishna, MD,d and Scott E. Olitsky, MDe We report the results of a comparative study at a single center on 214 eyes of 109 pediatric patients in whom IOP was measured using the Icare rebound tonometer and Goldmann applanation tonometry. Measurements from the two modalities demonstrated a correlation coefficient of 0.83 (P < 0.001), with Icare measuring on average 1.38 mm Hg higher. Compared to Goldmann, the Icare was more easily tolerated in the children studied. In 37 eyes that tolerated pachymetry, central corneal thickness was positively correlated with Icare measurements.
G
oldmann applanation tonometry (GAT) is generally considered the gold standard for measurement of intraocular pressure (IOP). Because it requires anesthetics and use of a slit-lamp, its use in children is limited. The Icare rebound tonometer (Icare TA01i; Icare Finland Oy) is a handheld device that
References 1. Gilbert C. Retinopathy of prematurity: a global perspective of the epidemics, population of babies at risk and implications for control. Early Hum Dev 2008;84:77-82. 2. Kemper AR, Wallace DK. Neonatologists’ practices and experiences in arranging retinopathy of prematurity screening services. Pediatrics 2007;120:527-31. 3. Wallace DK, Freedman SF, Zhao Z, Jung SH. Accuracy of ROPtool vs individual examiners in assessing retinal vascular tortuosity. Arch Ophthalmol 2007;125:1523-30. 4. Wallace DK, Zhao Z, Freedman SF. A pilot study using “ROPtool” to quantify plus disease in retinopathy of prematurity. J AAPOS 2007;11: 381-7.
Author affiliations: aUniversity Hospitals Eye Institute, Cleveland, Ohio; bCase Western Reserve University School of Medicine, Cleveland, Ohio; cCase Western Reserve University Department of Epidemiology & Biostatistics, Cleveland, Ohio; dSabates Eye Centers, Kansas City, Missouri; eChildren’s Mercy Hospital, Kansas City, Missouri Submitted April 23, 2015. Revision accepted August 9, 2015. Correspondence: Florin Grigorian, MD, University Hospitals Eye Institute, 6001B Landerhaven Dr., Mayfield Hts, OH 44124 (email: [email protected]). J AAPOS 2015;19:572-574. Copyright Ó 2015 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/$36.00 http://dx.doi.org/10.1016/j.jaapos.2015.08.009
Journal of AAPOS
Vickers et al
Volume 19 Number 6 / December 2015
RPE atrophy is widespread, often with a mottled or reticulated appearance. Intraretinal pigment migration in the mid to far periphery is typical and often becomes heavier as children get older, at which time it can also occur more centrally. Central macular atrophy occurs in all cases, sometimes with a yellow discoloration. Cycloplegic refraction is often hyperopic. Sometimes paraarteriolar sparing can be appreciated. Although previous reports have confirmed these characteristic features,1-3 the presence or absence or type of strabismus is typically not mentioned. Strabismus is generally nonspecific in childhood retinal dystrophies. In our experience, different horizontal and/ or vertical deviations are common but incomitant vertical deviations are uncommon, even with profound visual loss. Our observation of inability to supraduct in these 4 children with retinal dystrophy who were subsequently confirmed to harbor recessive RDH12 mutations suggests this form of strabismus could be a recurrent finding for a subset of children with this form of retinal dystrophy. It is possible that the finding could be related to the level of visual loss in these children rather than the specific type of retinal dystrophy; however, 1 affected child did have best-corrected visual acuity as good as 20/100 (subject 2). Further studies are needed to better understand how frequently elevation deficiency occurs in RDH12-related retinopathy and potentially in other genetic forms of retinal dystrophy. The main differential diagnosis for elevation deficiency with retinal dystrophy has classically been neurological disease, which is typically acquired and of later onset. Such neurological disease includes KearnsSayre syndrome and related mitochondrial disorders,8 spinocerebellar ataxia,9 and potentially neurodegeneration with brain iron accumulation.10 References 1. Schuster A, Janecke AR, Wilke R, et al. The phenotype of early-onset retinal degeneration in persons with RDH12 mutations. Invest Ophthalmol Vis Sci 2007;48:1824-31. 2. Valverde D, Pereiro I, Vallespin E, Ayuso C, Borrego S, Baiget M. Complexity of phenotype-genotype correlations in Spanish patients with RDH12 mutations. Invest Ophthalmol Vis Sci 2009;50:1065-8. 3. Mackay DS, Dev Borman A, Moradi P, et al. RDH12 retinopathy: novel mutations and phenotypic description. Mol Vis 2011;17:2706-16. 4. Abu-Safieh L, Alrashed M, Anazi S, et al. Autozygome-guided exome sequencing in retinal dystrophy patients reveals pathogenetic mutations and novel candidate disease genes. Genome Res 2013;23: 236-47. 5. Janecke AR, Thompson DA, Utermann G, et al. Mutations in RDH12 encoding a photoreceptor cell retinol dehydrogenase cause childhood-onset severe retinal dystrophy. Nat Genet 2004;36:850-54. 6. Perrault I, Hanein S, Gerber S, et al. Retinal dehydrogenase 12 (RDH12) mutations in Leber congenital amaurosis. Am J Hum Genet 2004;75:639-46. 7. Thompson DA, Janecke AR, Lange J, et al. Retinal degeneration associated with RDH12 mutations results from decreased 11-cis retinal synthesis due to disruption of the visual cycle. Hum Mol Genet 2005;14:3865-75. 8. Gronlund MA, Honarvar AK, Andersson S, et al. Ophthalmological findings in children and young adults with genetically verified mitochondrial disease. Br J Ophthalmol 2010;94:121-7.
9. Aleman TS, Cideciyan AV, Volpe NJ, Stevanin G, Brice A, Jacobson SG. Spinocerebellar ataxia type 7 (SCA7) shows a conerod dystrophy phenotype. Exp Eye Res 2002;74:737-45. 10. Khan AO, AlDrees A, Elmalik SA, et al. Ophthalmic features of PLA2G6-related paediatric neurodegeneration with brain iron accumulation. Br J Ophthalmol 2014;98:889-93.
ROPtool analysis of images acquired using a noncontact handheld fundus camera (Pictor)—a pilot study Laura A. Vickers, MD, Sharon F. Freedman, MD, David K. Wallace, MD, MPH, and S. Grace Prakalapakorn, MD, MPH The presence of plus disease is the primary indication for treatment of retinopathy of prematurity (ROP), but its diagnosis is subjective and prone to error. ROPtool is a semiautomated computer program that quantifies vascular tortuosity and dilation. Pictor is an FDAapproved, noncontact, handheld digital fundus camera. This pilot study evaluated ROPtool’s ability to analyze high-quality Pictor images of premature infants and its accuracy in diagnosing plus disease compared to clinical examination. In our small sample of images, ROPtool could trace and identify the presence of plus disease with high accuracy.
R
etinopathy of prematurity (ROP) is a leading cause of blindness in children in the industrialized world.1 Treatment depends on timely screening and diagnosis, but there are too few ophthalmologists available to screen for ROP worldwide.2 One strategy to overcome this barrier includes an ROP screening system using semiautomated analysis of retinal photographs to identify infants that may need treatment. Prior studies have shown that ROPtool analysis of images captured by RetCam and video indirect ophthalmoscopy (VIO) can diagnose plus disease with high accuracy compared to clinical diagnosis.3-8 The Pictor camera (Volk Optical, Mentor, OH) is considerably less expensive than Retcam and can capture still images of higher quality than VIO. A recent study showed that the Pictor camera can capture retinal
Author affiliations: Duke University Eye Center, Durham, North Carolina Dr. Prakalapakorn is supported by NIH K23EY024268. The funding organization had no role in the design or conduct of this research. Submitted May 6, 2015. Revision accepted July 28, 2015. Correspondence: S. Grace Prakalapakorn, MD, MPH, Assistant Professor of Ophthalmology and Pediatrics, Duke University, DUMC 3802, 2351 Erwin Road, Durham, NC, 27710 (email: [email protected]). J AAPOS 2015;19:570-572. Copyright Ó 2015 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/$36.00 http://dx.doi.org/10.1016/j.jaapos.2015.07.291
Journal of AAPOS
Volume 19 Number 6 / December 2015
Vickers et al
571
images of premature infants with sufficient quality for grading of pre-plus or plus disease by two ROP experts with high sensitivity (79% and 85%) and specificity (100% and 83%).9 The present pilot study evaluates the feasibility and accuracy of analyzing high-quality Pictor images with ROPtool for plus disease.
Methods This pilot study was approved by the Duke Health System Institutional Review Board and complied with regulations of the US Health Insurance Portability and Accountability Act of 1996. A subset of Pictor images graded by two pediatric ophthalmologists experienced in ROP screening (SFF and DKW) for image quality (good, fair, or poor) in a previous study were retrospectively analyzed.9 The images were obtained without a lid speculum during ROP rounds at Duke University Hospital Neonatal Intensive Care Nursery from December 2011 to May 2012. For an infant to be included in the present study, an image of at least one eye had to be considered of fair or good quality by both graders and to have at least one major vessel visible for one disk diameter in length from the optic nerve in all quadrants. For each infant, the best image from one eye based on the above criteria was selected. We used ROPtool v2.1.8 to analyze the Pictor images in random order. An image was “traceable” by ROPtool if all four quadrants were traceable; a quadrant was “traceable” if it contained one vessel at least one disk diameter in length that could be traced by ROPtool. The most tortuous major vessel in each quadrant was traced. Because the diagnosis of plus disease requires sufficient dilation and tortuosity in at least two quadrants, the second most tortuous vessel in each image was analyzed. One of the authors (LAV) performed all ROPtool analysis. Analyses was limited to the ROPtool indices tortuosity and tortuosity weighted plus (TWP), which is a combined measure of dilation and tortuosity that gives more weight to dilation as tortuosity increases.5 Receiver operating characteristic (ROC) curves were calculated to determine the accuracy of ROPtool in assessing the presence of plus or “pre-plus or plus” disease compared to the reference standard clinical examination diagnosis given by one of two ROP experts (SFF and DKW) on the same date the photographs were obtained. All statistical analysis was performed with SAS v.9.1.3 (SAS Institute Inc, Cary, NC).
Results Of the 48 infants included in the previous study, all had fair or good quality images in at least one eye (47 [98%] right eye images and 44 [92%] left eye images), 37 (77%) infants had an image of at least one eye with fair or good quality with one major vessel visible for at least one disk diameter length from the optic nerve in all quadrants. Of these 37 images, 35 (95%) were traceable, that is, had four quadrants traceable by ROPtool. Of the 35 traceable images, 3 (8.6%) had plus and 1 (3%) had pre-plus disease based on the reference standard clinical examination. Using the ROPtool parameters of tortuosity
Journal of AAPOS
FIG 1. Receiver operating characteristic curves for Pictor images using tortuosity and tortuosity weighted plus (TWP) compared to clinical diagnosis of plus disease (A), or “pre-plus or plus” disease (B) as the outcome. AUC, area under the curve.
and TWP, the area under the curve (AUC) of the ROC curve for the diagnosis of plus disease was 0.99 for tortuosity and 0.99 for TWP; for pre-plus or plus disease the AUC was 1.0 for tortuosity and 0.98 for TWP (Figure 1).
Discussion High-quality Pictor images of the retina of premature infants are traceable and can be analyzed using ROPtool
572
Grigorian et al
with high accuracy for diagnosing plus disease. This is the first study showing ROPtool’s ability to accurately analyze images obtained using a handheld, noncontact camera. The ROPtool parameters tortuosity and TWP both show high accuracy for diagnosing plus disease in Pictor images. We considered tortuosity alone as one parameter because previous studies found that ROPtool can accurately measure retinal tortuosity in high-quality RetCam images5,7,10 and tortuosity alone has been shown to be highly correlated with plus disease diagnosis.4 We investigated TWP because as a combined measure, TWP has high accuracy to diagnose plus disease in RetCam images.5 Future studies should investigate how well the ROPtool parameters of tortuosity and TWP perform using lower quality Pictor images. Semiautomated diagnosis of plus disease in ROP using images acquired from a handheld, noncontact camera advances efforts to increase the objectivity, automation, safety, and efficiency of ROP screening. RetCam requires contact with the cornea, and VIO requires an examiner trained in indirect ophthalmoscopy (eg, an ophthalmologist or optometrist). By contrast, a less qualified imager (eg, nonophthalmologist healthcare worker) can capture fundus images using Pictor with less risk for damage to the cornea (eg, corneal abrasion or infection), because no corneal contact is involved. ROPtool analysis of Pictor images could also be carried out by trained non-physician healthcare workers, increasing automation and objectivity in screening while expanding our screening workforce beyond ophthalmologists. As more of the ROP screening process is shown to be safely and accurately carried out by nonophthalmologists, ophthalmologists may focus their efforts on infants requiring treatment. This pilot study is limited by the relatively small number of images and inclusion of only high-quality images. Also, ROPtool depends on user input to define the border of the optic nerve head and center of the macula, which introduces interuser variability in analysis. To address these limitations, future studies should include a larger number of images of varying image quality and multiple ROPtool users to simulate a semiautomated ROP screening process.
Volume 19 Number 6 / December 2015 5. Cabrera MT, Freedman SF, Kiely AE, et al. Combining ROPtool measurements of vascular tortuosity and width to quantify plus disease in retinopathy of prematurity. J AAPOS 2011;15:40-44. 6. Wallace DK, Freedman SF, Zhao Z. A pilot study using ROPtool to measure retinal vascular dilation. Retina 2009;29:1182-7. 7. Kiely AE, Wallace DK, Freedman SF, Zhao Z. Computer-assisted measurement of retinal vascular width and tortuosity in retinopathy of prematurity. Arch Ophthalmol 2010;128:847-52. 8. Cabrera MT, Freedman SF, Hartnett ME, Stinnett SS, Chen BB, Wallace DK. Real-time, computer-assisted quantification of plus disease in retinopathy of prematurity at the bedside. Ophthalmic Surg Lasers Imaging Retina 2014;45:542-8. 9. Prakalapakorn SG, Wallace DK, Freedman SF. Retinal imaging in premature infants using the Pictor noncontact digital camera. J AAPOS 2014;18:321-6. 10. Wallace DK, Freedman SF, Zhao Z. Evolution of plus disease in retinopathy of prematurity: quantification by ROPtool. Trans Am Ophthalmol Soc 2009;107:47-52.
Comparison of the Icare rebound tonometry with the Goldmann applanation tonometry in a pediatric population Florin Grigorian, MD,a A. Paula Grigorian, MD,a Ang Li, AB,b Abdus Sattar, PhD,c Rohit Krishna, MD,d and Scott E. Olitsky, MDe We report the results of a comparative study at a single center on 214 eyes of 109 pediatric patients in whom IOP was measured using the Icare rebound tonometer and Goldmann applanation tonometry. Measurements from the two modalities demonstrated a correlation coefficient of 0.83 (P < 0.001), with Icare measuring on average 1.38 mm Hg higher. Compared to Goldmann, the Icare was more easily tolerated in the children studied. In 37 eyes that tolerated pachymetry, central corneal thickness was positively correlated with Icare measurements.
G
oldmann applanation tonometry (GAT) is generally considered the gold standard for measurement of intraocular pressure (IOP). Because it requires anesthetics and use of a slit-lamp, its use in children is limited. The Icare rebound tonometer (Icare TA01i; Icare Finland Oy) is a handheld device that
References 1. Gilbert C. Retinopathy of prematurity: a global perspective of the epidemics, population of babies at risk and implications for control. Early Hum Dev 2008;84:77-82. 2. Kemper AR, Wallace DK. Neonatologists’ practices and experiences in arranging retinopathy of prematurity screening services. Pediatrics 2007;120:527-31. 3. Wallace DK, Freedman SF, Zhao Z, Jung SH. Accuracy of ROPtool vs individual examiners in assessing retinal vascular tortuosity. Arch Ophthalmol 2007;125:1523-30. 4. Wallace DK, Zhao Z, Freedman SF. A pilot study using “ROPtool” to quantify plus disease in retinopathy of prematurity. J AAPOS 2007;11: 381-7.
Author affiliations: aUniversity Hospitals Eye Institute, Cleveland, Ohio; bCase Western Reserve University School of Medicine, Cleveland, Ohio; cCase Western Reserve University Department of Epidemiology & Biostatistics, Cleveland, Ohio; dSabates Eye Centers, Kansas City, Missouri; eChildren’s Mercy Hospital, Kansas City, Missouri Submitted April 23, 2015. Revision accepted August 9, 2015. Correspondence: Florin Grigorian, MD, University Hospitals Eye Institute, 6001B Landerhaven Dr., Mayfield Hts, OH 44124 (email: [email protected]). J AAPOS 2015;19:572-574. Copyright Ó 2015 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/$36.00 http://dx.doi.org/10.1016/j.jaapos.2015.08.009
Journal of AAPOS