An international comparison of retinopathy of prematurity grading performance within the Benefits of Oxygen Saturation Targeting II trials.

PurposeTo investigate whether the observed international differences in retinopathy of prematurity (ROP) treatment rates within the Benefits of Oxygen Saturation Targeting (BOOST) II trials might have been caused by international variation in ROP disease grading.MethodsGroups of BOOST II trial ophthalmologists in UK, Australia, and New Zealand (ANZ), and an international reference group (INT) used a web based system to grade a selection of RetCam images of ROP acquired during the BOOST II UK trial. Rates of decisions to treat, plus disease grading, ROP stage grading, ROP zone grading, inter-observer variation within groups and intra-observer variation within groups were measured.ResultsForty-two eye examinations were graded. UK ophthalmologists diagnosed treat-requiring ROP more frequently than ANZ ophthalmologists, 13.9 (3.49) compared to 9.4 (4.46) eye examinations, P=0.038. UK ophthalmologists diagnosed plus disease more frequently than ANZ ophthalmologists, 14.1 (6.23) compared to 8.5 (3.24) eye examinations, P=0.021. ANZ ophthalmologists diagnosed stage 2 ROP more frequently than UK ophthalmologists, 20.2 (5.8) compared to 12.7 (7.1) eye examinations, P=0.026. There were no other significant differences in the grading of ROP stage or zone. Inter-observer variation was higher within the UK group than within the ANZ group. Intra-observer variation was low in both groups.ConclusionsWe have found evidence of international variation in the diagnosis of treatment-requiring ROP. Improved standardisation of the diagnosis of treatment-requiring ROP is required. Measures might include improved training in the grading of ROP, using an international approach, and further development of ROP image analysis software.

Global prevalence of childhood cataract: a systematic review.

Childhood cataract is an avoidable cause of visual disability worldwide and is a priority for VISION 2020: The Right to Sight. There is a paucity of information about the burden of cataract in children and the aim of this review is to assess the global prevalence of childhood cataract. The methodology for the review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We performed a literature search for studies reporting estimates of prevalence or incidence of cataract among children (aged<18 years) at any global location using the Cochrane Library, Medline and Embase up to January 2015. No restrictions were imposed based on language or year of publication. Study quality was assessed using a critical appraisal tool designed for systematic reviews of prevalence. Twenty prevalence and four incidence studies of childhood cataract from five different geographical regions were included. The overall prevalence of childhood cataract and congenital cataract was in the range from 0.32 to 22.9/10000 children (median=1.03) and 0.63 to 9.74/10000 (median=1.71), respectively. The incidence ranged from 1.8 to 3.6/10000 per year. The prevalence of childhood cataract in low-income economies was found to be 0.42 to 2.05 compared with 0.63 to 13.6/10000 in high-income economies. There was no difference in the prevalence based on laterality or gender. This review highlights substantial gaps in the epidemiological knowledge of childhood cataract worldwide, particularly from low and lower middle-income economies. More studies are needed using standard definitions and case ascertainment methods with large enough sample sizes.

The effect of oxygen saturation targeting on retinal blood vessel growth using retinal image data from the BOOST-II UK Trial.

PURPOSE: Retinopathy of prematurity (ROP) is a disorder of developing retinal blood vessels in preterm infants. The purpose of this nested study was to investigate the effects of higher (91-95%) and lower (85-89%) oxygen saturation (SpO2) targeting on retinal blood vessel growth in preterm infants. METHODS: Retinal blood vessel growth in the higher (91-95%) and lower (85-89%) oxygen saturation (SpO2) targeting groups was compared. Suitable RetCam (Clarity, Pleasanton, CA, USA) images collected in the BOOST-II UK trial were used. The distances between the centre of the optic disc and the ROP ridge in the temporal and nasal retina were measured in pixel units. RESULTS: Images from 38 infants were studied, 20 from the higher SpO2 target group and 18 from the lower SpO2 target group. On average, temporal blood vessels extended further from the optic disc than nasal blood vessels, mean (standard deviation (SD)) 463.39 (55.05) pixels compared with 360.13 (44.47) pixels, respectively, P<0.0001. Temporal blood vessels extended less far from the optic disc in the higher SpO2 target group than in the lower SpO2 target group: mean (SD) 449.83 (56.16) pixels compared with 480.02 (49.94), respectively, P=0.055. Nasal retinal blood vessel measurements were broadly similar in the higher and lower SpO2 target groups; mean (SD) 353.96 (41.95) compared with 370.00 (48.82) pixels, respectively, P=0.38. CONCLUSIONS: Relatively high oxygen saturation targeting (91-95%) was associated with a trend (P=0.055) towards reduced retinal blood vessel growth in this study of preterm infants.

Ophthalmological problems associated with preterm birth.

As survival of preterm infants improves, the long-term care of consequent ophthalmic problems is an expanding field. Preterm birth can inflict a host of challenges on the developing ocular system, resulting in the visual manifestations of varied significance and pathological scope. The ophthalmic condition most commonly associated with preterm birth is retinopathy of prematurity, which has the potential to result in devastating vision loss. However, the visual compromise from increased incidence of refractive errors, strabismus, and cerebral vision impairment has significant impact on visual function, which also has influence on other developmental aspects including psychological and educational. In this review, the normal ocular development is discussed, aiming to exemplify the impact of early exteriorisation on one of the more naive organs of prematurity. This is then related to the incidence and visual consequences of many types of deficit, including refractive error, strabismus, and loss of visual function in preterm populations, with comparisons to term infant studies. Often these conditions are linked with causal and resultant factors being impossible to segregate, but the common factor of increased rates of all types of ophthalmic deficits demonstrates that children born prematurely are indeed premature for life.

Do infants of birth weight less than 1500 g require additional long term ophthalmic follow up?

AIM: To survey existing ophthalmic follow up protocols in the United Kingdom for very low birthweight (VLBW) children. In addition, relative risk analysis was performed using data from a cohort study to assess which factors (birth weight, gestational age, retinopathy of prematurity (ROP) status) led to a high risk of developing amblyogenic factors. METHODS: Questionnaires were sent to every orthoptic department in the United Kingdom (n = 288) for information on their policy on the follow up of VLBW children. RESULTS: Responses were received from 125 departments (43%). There was a large variation in criteria used for follow up; 21% of respondents using birth weight (BW) and gestational age (GA), 22% using stage 3 or treated ROP, the remainder using a combination of these factors. There was no consensus regarding when follow up should commence (from 3 months to 3 years) or cease (1-8 years). Relative risk analysis revealed that birth weight under 1500 g, GA under 33 weeks, and the presence of severe ROP were significant risk factors for developing one or more amblyogenic factors. CONCLUSION: There is no consensus on whether VLBW children need to be reviewed. There is a greatly increased risk of ophthalmic deficits in those with severe ROP or severe neurological disorders, and also in those with mild or no ROP. Children in the latter group who are not routinely followed up, have a high risk of developing treatable refractive errors and strabismus. This raises the question of whether an additional screening examination is merited.

Change of refractive state and eye size in children of birth weight less than 1701 g.

AIMS: To determine the refractive status and ocular dimensions of a cohort of children at age 10-12 years with birth weight below 1701 g, and also the relation between the neonatal ophthalmic findings and subsequent refractive state. METHODS: 293 low birthweight children who had been examined in the neonatal period were assessed at 10-12 years of age. The examination consisted of autorefraction, keratometry, and A-scan. Results of right eyes were compared with published normative data. RESULTS: 293 of the birth cohort of 572 children consented to participate. The average mean spherical equivalent (MSE) in the low birthweight cohort was +0.691 dioptre, significantly higher than the control data (+0.30D, p = 0.02). The average change in MSE over the 10-12 year period was -1.00 dioptre (n = 256), but only 62.1% of cases showed a shift in refractive error of the appropriate magnitude and direction. The presence of any retinopathy of prematurity (ROP) increases the risk of developing anisometropia sixfold. CONCLUSIONS: Low birth weight and ROP both significantly impact the refractive state in the long term. At age 10-12 years children born preterm have an increased prevalence of all refractive errors. In low birthweight children refractive state is relatively stable over the first decade of life with a shift towards myopia of 1 dioptre.

The temporal retinal vessel angle and infants born preterm.

AIM: To determine the temporal retinal vessel angle in babies and its relation to preterm birth. METHODS: Digital images were obtained during routine screening for retinopathy of prematurity (ROP). The temporal retinal vessel angle was measured in 164 eyes of 82 babies born "very preterm" (24-27 weeks gestational age (GA)), "preterm" (28-31 weeks GA), and "near term" (>/=32 weeks GA). RESULTS: Mean temporal vessel angle (TVA) for all three GA groups together is 80.0 degrees (SD 17.0 degrees ) for the right eye and 80.5 degrees (16.7 degrees ) for the left eye. The range is right eye 59-106 degrees , left eye 69-97 degrees , with 95% data above 67 degrees for the right and 63 degrees for the left eye. For babies born near term, TVA is 82 degrees in each eye. There is a high degree of interocular symmetry between right and left eyes and a statistically insignificant trend for increasing TVA with increasing GA. The presence and stage of ROP affected one parameter of the left eye alone. CONCLUSIONS: These data provide normative data on the TVA in babies and will facilitate, especially if there is interocular asymmetry, determining whether there is macular displacement.

UK population based study of severe retinopathy of prematurity: screening, treatment, and outcome.

BACKGROUND: Retinopathy of prematurity (ROP) is one of the few causes of childhood blindness in which severe vision impairment is largely preventable. Ophthalmic screening for ROP is required to identify disease that requires treatment whereby the development of potentially blinding disease can be minimised. OBJECTIVES: To make the first UK population based estimate of the incidence of babies with severe ROP (stage 3 or more); to document their clinical characteristics and management and to evaluate the appropriateness of current ROP screening guidelines in the UK. PATIENTS: Cases were recruited through a national surveillance programme with 1 year ophthalmic follow up and data from clinician completed questionnaires. RESULTS: Between 1 December 1997 and 31 March 1999, 233 preterm babies with stage 3 ROP were identified. Severity (location, extent, and presence of plus disease) was associated with degree of prematurity, most severe in the most premature babies. Fifty nine percent were treated. The UK screening protocol was followed in two thirds of cases, but in the remainder it was begun too late or was too infrequent. Three quarters of the cases were followed up at 1 year, and 13% had a severe vision deficit as a result of ROP. CONCLUSIONS: Visual deficit as a result of ROP in premature babies continues to be a severe disability in some of the survivors of neonatal intensive care. Further efforts are needed to organise treatment regionally to improve outcome and standards of practice.

The first cut is the deepest: basic surgical training in ophthalmology.

PURPOSE: To examine the basic surgical training received by Senior House Officers (SHOs) in ophthalmology and the influence on training of sociodemographic and organisational factors. METHODS: Cross-sectional survey of SHOs in recognised UK surgical training posts asking about laboratory training and facilities, surgical experience, demographic details, with the opportunity to add comments. RESULTS: A total of 314/466 (67%) questionnaires were returned. In all, 67% had attended a basic surgical course, 40% had access to wet labs and 39% had spent time in a wet lab in the previous 6 months. The mean number of part phakoemulsification (phako) procedures performed per week was 0.79; the mean number of full phakos performed per week was 0.74. The number of part phakos performed was negatively correlated, and the number of full phakos completed was positively correlated, with length of time as an SHO. Respondents who had larger operating lists performed more full phakos per week (P<0.001). Compared to men, women were less likely to have access to a wet lab (P=0.013), had completed fewer full phakos per week (P=0.003), and were less likely to have completed 50 full phakos (P=0003). SHOs' comments revealed concerns about their limited 'hands on' experience. CONCLUSIONS: There are significant shortcomings in the basic surgical training SHOs receive, particularly in relation to wet lab experience and opportunities to perform full intraocular procedures. SHOs themselves perceive their training as inadequate. Women are disadvantaged in both laboratory and patient-based training, but minority ethnic groups and those who qualified overseas are not.

Refractive adaptation in amblyopia: quantification of effect and implications for practice.

AIM: To describe the visual response to spectacle correction ("refractive adaptation") for children with unilateral amblyopia as a function of age, type of amblyopia, and category of refractive error. METHOD: Measurement of corrected amblyopic and fellow eye logMAR visual acuity in newly diagnosed children. Measurements repeated at 6 weekly intervals for a total 18 weeks. RESULTS: Data were collected from 65 children of mean (SD) age 5.1 (1.4) years with previously untreated amblyopia and significant refractive error. Amblyopia was associated with anisometropia in 18 (5.5 (1.4) years), strabismus in 16 (4.2 (0.98) years), and mixed in 31 (5.2 (1.5) years) of the study participants. Mean (SD) corrected visual acuity of amblyopic eyes improved significantly (p<0.001) from 0.67 (0.38) to 0.43 (0.37) logMAR: a mean improvement of 0.24 (0.18), range 0.0-0.6 log units. Change in logMAR visual acuity did not significantly differ as a function of amblyopia type (p = 0.29) (anisometropia 0.22 (0.13); mixed 0.18 (0.14); strabismic 0.30 (0.24)) or for age (p = 0.38) ("under 4 years" 0.23 (0.18); "4-6 years" 0.24 (0.20); "over 6 years" 0.16 (0.23)). CONCLUSION: Refractive adaptation is a distinct component of amblyopia treatment. To appropriately evaluate mainstream therapies such as occlusion and penalisation, the beneficial effects of refractive adaptation need to be fully differentiated. A consequence for clinical practice is that children may start occlusion with improved visual acuity, possibly enhancing compliance, and in some cases unnecessary patching will be avoided.

Visual function in low birthweight children.

AIM: To determine the visual functions, at age 10-12 years, of a geographically based cohort of children of birth weight less than 1701 g. The results were compared to a group of children born at full term. METHODS: 572 low birthweight (LBW) "low birthweight cohort" children who had been examined in the neonatal period were invited for review at 10-12 years of age. 169 11 year old schoolchildren born at full term were also recruited, "school cohort." Visual acuity (at distance and near), contrast sensitivity, colour vision, and visual fields were measured. RESULTS: 293 of the original 572 participants consented to a further examination. Compared to the school cohort of children born at term the low birthweight cohort showed significantly lower near and distance acuities and contrast sensitivity (p<0.001 for all uniocular and binocular measures). Retinopathy of prematurity (ROP) was a very poor predictor of outcome and multivariate analysis did not identify any key neonatal factors as predictors of long term visual outcome. CONCLUSIONS: Low birthweight children have a small but statistically significant deficit in both visual acuity and contrast sensitivity. Low birth weight and ROP both impact on long term visual functions.

A comparison of findings on parents' and teachers' questionnaires, and detailed ophthalmic and psychological assessments.

BACKGROUND: Questionnaires are important tools used to gain information about health and level of function in different domains. AIMS AND METHODS: To determine the degree of agreement between questionnaires, administered to parents and teachers, and ophthalmic and psychological examinations in a cohort of 309 low birth weight children (<1701 g) at age 10-13 years. RESULTS: A total of 90.9% of cases showed agreement between the question on distance vision and clinical assessment, and agreement for the near vision question was 83%. However, the correlation on an individual basis was only fair (kappa = 0.46, distance vision) to poor (kappa = 0.2, near vision). The overall agreement for the questions on cognitive ability was better than the correlation, whereas the questions on reading and mathematical ability showed low agreement and low correlation. CONCLUSION: Questionnaire assessment of vision and cognitive ability is more suitable for studying the outcome of a large population than for identifying deficits in individuals.

The state of basic surgical training in the UK: ophthalmology as a case example.

Concern is being expressed about the state of basic surgical training in the context of growing demands to improve service provision in the National Health Service. Taking ophthalmology as a case example, we sent questionnaires to all 466 senior house officers (SHOs) in recognized surgical training posts in England, Wales, Scotland and Northern Ireland. The main outcome measures were intraocular surgery performed in the previous two weeks and since starting as an SHO in ophthalmology; access to protected teaching time or cases on theatre lists; and supervision during surgery. Phakoemulsification, the most common type of cataract surgery, was used as a generic indicator of intraocular procedures. 314 (67%) of the SHOs responded. Of those working in the hospital in the previous two weeks, 50% had performed at least one component part of a phakoemulsification (phako) operation and 44% had performed at least one full phako operation. The average number of full phako operations done per week was 0.741. 77% reported some protected surgical teaching time over the two weeks and those with protected teaching time reported more full phako operations per week. Of those who had performed at least one surgical procedure in the previous two weeks, 79% had been supervised by a consultant. Of those who had completed two or more years' training as an SHO, only 42% met the Royal College of Ophthalmologists minimum requirement of 50 complete intraocular operations performed under supervision. Women were less likely than men, and SHOs in district general hospitals were less likely than those in teaching hospitals, to have achieved this target. As many as half the SHOs in ophthalmology are not receiving an adequate basic surgical training. If this continues it may prove difficult to train sufficient new surgeons to an acceptable standard to meet the increasing demands of an ageing population. This is not an issue for ophthalmology alone but for all surgical specialties.

Cytomegalovirus Retinitis in infancy.

PURPOSE: To describe the presentation of cytomegalovirus retinitis (CMVR) in a series of infants. METHODS: Immunocompromised infants with either HIV or systemic cytomegalovirus (CMV) were examined for CMVR. Ocular involvement was recorded and monitored by digital imaging. RESULTS: Five infants were detected to have CMVR. All the infants demonstrated changes within the macula. One infant progressed from a fine granular pattern to fulminant CMVR. CONCLUSION: Infants under a year with CMVR have a predilection for the disease to present at the macula, in contrast to the presentation in adults, which tends to involve more peripheral parts of the retina.

Semiautomated computer analysis of vessel growth in preterm infants without and with ROP.

AIMS: To measure characteristics of the retinal blood vessels close to the optic disc in full term and preterm infants, with and without retinopathy of prematurity (ROP), using digital imaging. To determine whether these measures are indicative of the presence or severity of ROP in the retinal periphery. METHODS: 52 digital fundus images from 42 babies were analysed with a semiautomated analysis program developed at Imperial College London. Analysis was limited to the principal temporal vessels close to the optic disc: recording venular diameter and arteriolar diameter and tortuosity. RESULTS: Each result was categorised by the gestational age of the infant ("very premature" 24-27 weeks, "moderately premature" 28-31 weeks, and "near term" > or =32 weeks) and by the highest stage of ROP present ("no ROP," "mild ROP" stage 1 or 2, and "severe ROP" stage 3). Arteriolar tortuosity was found to vary significantly (Kruskal-Wallis p=0.002) with ROP severity. Although venular and arteriolar diameters increased monotonically with ROP severity the differences were not significant. Venular diameter, arteriolar diameter, and arterial tortuosity did not vary significantly between gestational age groups. CONCLUSIONS: This study confirms it is possible to quantify the size and tortuosity of retinal blood vessels in term and preterm babies using digital image analysis software. This method detected significant increases in arteriolar tortuosity with increasing ROP severity.