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.

Localization of laminin to retinal vessels of the rat and mouse using whole mounts.

Using a whole mount procedure in adult and neonatal mice and adult rats, we have developed an immunohistochemical method for the localization of laminin-like immunoreactivity (LLIR) to the retinal vessels. LLIR was localized to the vascular basement membrane, permitting a clear three-dimensional view of the retinal vasculature. Positive stain was seen in the inner limiting membrane, in retracted capillaries, encasing pericytes, and in a banding pattern on retinal arterioles. The major findings with the whole mount preparations were confirmed using paraffin-embedded material, with the additional observation of LLIR in the lens capsule. In whole mounts of retinas from neonatal mice, LLIR was present from the earliest stages of capillary growth, indicating that laminin is likely to be secreted by endothelial cells during retinal angiogenesis. LLIR within the retinal nerve fiber layer does not precede capillary ingrowth, so no evidence was found that laminin acts as a tracker signal for retinal angiogenesis.

Do tinted lenses improve the reading performance of dyslexic children? A cohort study.

The use of tinted lenses as a method to improve reading skills in children with dyslexia has been a controversial issue in recent years. The purpose of the present study was to determine if tinted lenses cause a measurable improvement in the reading performance of dyslexic children. Twenty-four children aged 8 to 12 years participated in the study. Dyslexia was diagnosed in all children by psychological evaluation, and these children underwent an ophthalmic evaluation for inclusion into the study. Participants were graded for speed and accuracy as they read through spectacle frames that contained red-, blue-, yellow-, and green-tinted lenses, a neutral-density lens, and empty frames. All lenses for each subject were of the same density level, with subjects alternately distributed to one of two densities tested (0.12 or 0.30 log units). Each child was asked to select the lens condition that subjectively improved reading ability at the conclusion of testing. One-way analysis of variance of reading performance showed neither improvement nor deterioration attributable to lens color or density when applied to error rates (F = 1.73, P = .14 for a density of 0.12; F = 0.28, P = .92 for a density of 0.30) or to reading rates (F = 0.98, P = .44 for a density of 0.12; F = 0.81, P = .55 for a density of 0.30). In addition, the lens condition that was subjectively preferred by each child did not correlate with actual reading performance (chi 2 = 3.83, not significant; 11.07 needed for significance at P = .05).

Delayed orbital hemorrhage after routine strabismus surgery.

PURPOSE: To report a case of delayed rectus muscle hemorrhage after strabismus surgery. METHODS: Case report. RESULTS: Rectus muscle hemorrhage occurred 36 hours after strabismus surgery in a 26-year-old man, causing temporary loss of vision and reduced ocular motility. Urgent lateral cantholysis and orbital exploration to restore hemostasis were undertaken. Full recovery of vision occurred and a small residual motility disturbance was present 3 months postoperatively. CONCLUSION: Delayed rectus muscle hemorrhage poststrabismus surgery is rare but can have sight-threatening effects. When vision is threatened because of optic nerve compromise, urgent orbital exploration may allow full recovery of function.

The nanophthalmic macula.

AIMS: To define an unusual macular appearance found in association with nanophthalmos. METHODS: A case review. RESULTS: Seven children (aged 8 months to 17 years) with nanophthalmos were examined. They all exhibited the same clinical findings of an unusual yellow macula appearance with retinal folds and crowded optic discs. Visual electrophysiology performed in four cases was normal. CONCLUSION: A distinctive yellow macular pigmentation with associated chorioretinal folds and crowded optic discs is present in nanophthalmos. It is proposed that the retinal folds are due to a disparity between scleral and retinal growth while the macula discoloration is due to a congenital abnormality in arrangement or position of the luteal pigment and is not degenerative. Included in this case series is the second case in the literature of nanophthalmos associated with Kenny's syndrome. Inheritance of nanophthalmos appears to be autosomal recessive.

Oxygen-induced retinopathy: ultrastructure of vitreous new vessels in the kitten model.

Oxygen-induced retinopathy was produced by exposing 3-day-old kittens to 80% oxygen between 60 and 105 hours. They were then allowed to survive in room air until day 15, 21 or 28 when they were sacrificed after perfusion with colloidal carbon. Specimens were prepared for transmission electron microscopy. Ninety separate vitreous capillaries from oxygen-treated animals were examined. A total of 235 intercellular junctions were examined, 116 of them from the 15-day old animals. In the 15-day old animals, five junctions of 116 were open and the remainder were tight. No open junctions were seen in 21- or 28-day-old animals. In one capillary from a 15-day animal, fenestrated endothelium was seen in an aberrant, intraluminal loop of endothelium which formed no part of the blood/tissue barrier. The wall thickness of the vitreous new vessels seemed to decrease and the number of vesicles and vacuoles appeared to increase with increasing age. The basement membrane of the vitreous new vessels was scanty. In some sections, cells, presumably macrophages, were seen outside the new vessels. It is concluded that the increased permeability of the vitreous new vessels in 15-day-old animals can be explained by, and is possibly totally due to, the presence of open endothelial junctions.

Proximal arterial vasoconstriction precedes regression of the hyaloid vasculature.

PURPOSE: To determine whether constriction of proximal arterial vessels precedes involution of the distal hyaloid vasculature in the mouse, under normal conditions, and whether this vasoconstriction is less pronounced when the distal hyaloid network persists, as it does in oxygen-induced retinopathy (OIR). METHODS: Photomicrographs of the vasa hyaloidea propria were analysed from pre-term pups (1-2 days prior to birth), and on Days 1-11 post-birth. The OIR model involved exposing pups to approximately 90% O(2) from D1-5, followed by return to ambient air. At sampling times pups were anaesthetised and perfused with india ink. Retinal flatmounts were also incubated with FITC-lectin (BS-1, G. simplicifolia,); this labels all vessels, allowing identification of vessels not patent to the perfusate. RESULTS: Mean diameter of proximal hyaloid vessels in pre-term pups was 25.44 +/- 1.98 microm; +/- 1 SEM). Within 3-12 hrs of birth, significant vasoconstriction was evident (diameter:12.45 +/- 0.88 microm), and normal hyaloid regression subsequently occurred. Similar vasoconstriction occurred in the O(2)-treated group, but this was reversed upon return to room air, with significant dilation of proximal vessels by D7 (diameter: 31.75 +/- 11.99 microm) and distal hyaloid vessels subsequently became enlarged and tortuous. CONCLUSIONS: Under normal conditions, vasoconstriction of proximal hyaloid vessels occurs at birth, preceding attenuation of distal hyaloid vessels. Vasoconstriction also occurs in O(2)-treated pups during treatment, but upon return to room air, the remaining hyaloid vessels dilate proximally, and the distal vessels become dilated and tortuous. These observations support the contention that regression of the hyaloid network is dependent, in the first instance, on proximal arterial vasoconstriction.

Angle-closure glaucoma after laser treatment for retinopathy of prematurity.

Laser photocoagulation has become the standard for treatment of retinopathy of prematurity. In general, it has been found to be a safe and effective means of retinal ablation. We report a case of angle-closure glaucoma in an infant after diode laser treatment for retinopathy of prematurity, which required bilateral surgical peripheral iridectomies.

Results of treatment of superior oblique overaction by silicone tendon-expander technique.

PURPOSE: To report the results of treatment of a series of patients with superior oblique overaction using the superior oblique silicone tendon-expander technique. METHODS: A chart review of 17 patients with superior oblique overaction who had a total of 26 silicone tendon-expander procedures was conducted. RESULTS: Mean preoperative degree of superior oblique overaction was +2.7. 92% of eyes had mild (+1) or no residual overaction at last postoperative assessment (follow-up range: 6 to 59 months). Of 15 patients with preoperative A-pattern of 10 prism diopter (delta) or more, only two patients (13%) had A-pattern of 10 delta or more at last assessment. Of 13 patients with preoperative hypotropia in primary position, five patients (38%) had no vertical deviation in primary position, and seven patients (54%) had persistent, but less vertical deviation in primary position at last assessment (mean reduced from 11 delta to 4 delta). No patient manifested superior oblique palsy at their last postoperative assessment. CONCLUSIONS: We believe that the superior oblique tendon-expander technique should be strongly considered for the treatment of superior oblique overaction associated with A-pattern or hypotropia in primary position, because it has a high success rate and a low incidence of postoperative complications. Consecutive superior oblique underaction did not occur in this series.

Telepaediatrics and diabetic retinopathy screening of young people with diabetes in Queensland.

We have examined the feasibility of a telemedicine-enabled screening service for children and adolescents with diabetes in Queensland. There are approximately 1400 young people with diabetes in Queensland and only about two-thirds of them are screened in accordance with international guidelines. A regional retinal screening service was established using a nonmydriatic digital retinal camera. Seven centres volunteered to participate in the study. During a five-month pilot trial, 83 of the young people with diabetes who attend these centres underwent digital retinal screening (3.7%). Retinal images were sent via email to a paediatric ophthalmologist for review and results were returned via email. A copy of each participant's results was forwarded by mail to the referring diabetes doctor and the participant and family. The majority of the image files (96%) were rated as excellent or good. Only one participant was identified as having an abnormal result. Participants and their families expressed satisfaction with the digital retinal screening process.

Posterior to the ridge laser treatment for severe stage 3 retinopathy of prematurity.

BACKGROUND: Current methods of treating the avascular retina with laser photocoagulation for severe retinopathy of prematurity (ROP) are not completely effective in the reduction of visual morbidity. We report a case series in which additional laser treatment, called 'posterior laser', was delivered posterior to the neovascular ridge, for eyes with severe stage 3 ROP in zone II with avascular retina posterior to the ridge. DESIGN: Retrospective chart review. PARTICIPANTS: Infants who underwent laser treatment, posterior to the neovascular ridge for severe ROP at the Alberta Children's Hospital, between January 2005 and October 2008. METHODS: Charts were reviewed for 18 eyes of 11 patients and collected information included demographic data, clinical examination results, and digital retinal images. MAIN OUTCOME MEASURES: Structural and functional outcomes of treatment. RESULTS: Four (22%) of 18 eyes received 'posterior laser' as primary treatment and the remainder of eyes (78%) received 'posterior laser' following previous laser photocoagulation anterior to the neovascular ridge. Mean birthweight was 688 g (552-930) and mean gestational age was 24 weeks (23-28). There were no complications because of the posterior laser treatment. In all, 16 of 18 eyes experienced rapid regression of the ridge and subsequent decrease in vascular dilation and tortuosity within 1 week. Two eyes required vitrectomy for 4A retinal detachment; however, no eyes developed stage 4B ROP. CONCLUSION: Posterior to the ridge laser in the setting of the morphological criteria described had no increased safety concerns and resulted in rapid regression of ROP with good outcomes.

Visual acuity testability and comparability in Australian preschool children: the Sydney Paediatric Eye Disease Study.

PURPOSE: To establish standardised protocols for vision screening, testability and comparability of three different vision tests were examined in a population-based, cross-sectional sample of preschool children (Sydney Paediatric Eye Disease Study). METHODS: Measurement of presenting monocular distance visual acuity (VA) using the Amblyopia Treatment Study (ATS) HOTV protocol, was attempted by all (1774) children aged≥24 months. In addition, in children aged≥60 months (576), VA was also tested using the logMAR retro-illuminated HOTV or Early Treatment Diabetic Retinopathy Study (ETDRS) linear charts (CSV 1000). Children able to have both eyes tested monocularly were considered. RESULTS: Testability significantly increased with age for all VA tests. The ATS HOTV with an overall testability of 80% (females: 82%, males: 78%) was the most testable of the VA tests (P<0.0001). In children aged <3 years testability was low (≤47%) rising to≥80% in children aged≥3. In children≥60 months, testability was higher for the HOTV (94%) than the ETDRS (59%) chart. In those that did two VA tests, mean difference of the ATS HOTV compared with the HOTV(CSV) was -0.1, and compared with ETDRS was -0.12 (P<0.0001). CONCLUSIONS: Children aged <3 years had poor VA testability, whereas those 3 years and above were highly testable using the ATS HOTV. The HOTV (CSV) retro-illuminated test was appropriate for children aged >5 years, and may be possible in younger children with early educational exposure. When comparing VA measures using these tests, the higher VA attained using the ATS HOTV, needs to be taken into account.

Three horizontal muscle surgery for large-angle infantile esotropia: validation of a table of amounts of surgery.

PURPOSE: To validate a table of amounts of three horizontal muscle surgery in patients with large-angle infantile esotropia (≥60 prism dioptres, PD). METHODS: A prospective interventional case series reporting the postoperative alignment of 51 patients (27 male, 24 female) over a 15-year period was conducted. Surgery amounts were according to a published table developed on a previous patient cohort (n=49), using bilateral medial rectus recession with graded unilateral lateral rectus resection. Kaplan-Meier life-table survival curves were formulated for success to orthotropia (±10 PD) after one and subsequent horizontal muscle surgeries for up to 8 years follow-up. RESULTS: The median preoperative deviation was 65 PD (range 60-80 PD) and median age at surgery was 11.8 months (range 5.1 months-3.6 years). Surgical success to orthotropia (±10 PD) after one surgery was 100% at 2 months, 95.7% at 6 months, 91.3% at 12 months, 77.8% at 4 years, and 73.6% at 8 years. Postoperative failure requiring further horizontal surgery occurred in 17.6% (residual esotropia 4, consecutive exotropia 5). CONCLUSIONS: Our second cohort has reproduced the success rate of the previous cohort (77.8% vs 77.1% at 4 years). If the published table of surgical amounts is used, three horizontal muscle surgery in large-angle infantile esotropia (≥60 PD) appears to have a good long-term success rate, and does not lead to the high rates of either residual esotropia or consecutive exotropia reported by others in the literature.

Selective inner retinal dysfunction precedes ganglion cell loss in a mouse glaucoma model.

BACKGROUND/AIMS: To correlate ganglion cell function with defined parameters of the elevated intraocular pressure profile (IOP) in a mouse glaucoma model and to determine the temporal relationship of these functional changes with ganglion cell death. METHODS: Unilateral chronic ocular hypertension was induced in C57BL6/J mice by laser ablation of the limbal episcleral veins. Scotopic flash electroretinograms were recorded after 5, 10, 20, and 40 days to isolate specific outer and inner retinal responses. Inner retinal function was correlated with the pressure differential between treated and non-treated eyes at the time of electroretinographic recording, and with the cumulative IOP insult (the integral of the IOP.time profile). Peripheral and central ganglion cell densities were quantified by Brn-3 immunohistochemistry. RESULTS: Elevated IOP induced a preferential deficit in inner retinal function. The positive scotopic threshold response (pSTR) was suppressed by 68% on day 5, by 50% on day 10, by 54% on day 20 and by 46% on day 40 after laser treatment. Inhibition of the STR correlated with the pressure differential between treated and non-treated eyes but not with the IOP.time integral. Inner retinal dysfunction preceded the progressive death of ganglion cells. Ganglion cell loss occurred preferentially in peripheral retina and correlated with the cumulative IOP insult. CONCLUSION: We have demonstrated specific inner retinal dysfunction in an inducible mouse glaucoma model. STRs are sensitive to elevated IOP per se, and their early suppression reflects ganglion cell dysfunction rather than cell death. The correlation between IOP elevation and suppression of inner retinal function, in the context of the temporal progression of ganglion cell death, suggests that a portion of the IOP-mediated ganglion cell dysfunction may be reversible.