C J MacEwen

The Dundee University Scottish Keratoconus study : demographics, corneal signs, associated diseases, and eye rubbing

AimTo investigate and correlate the corneal, refractive, topographic and familial characteristics of a large cohort with keratoconus.MethodsProspective observational study of 200 consecutive patients presenting with keratoconus during the 4 year-period 1997–2000. Subjects were examined at enrolment and at a final review. Data were collected on demographic characteristics, referral route, symptoms, refractive correction, eye rubbing, family history, medical history, slit-lamp biomicroscopic corneal signs, and computerized corneal topography.ResultsMean age at enrolment was 30.9±10.4 (range, 12.2–72) years (N=200, 62.5% male, 93% white Caucasian) with a 5% family history of keratoconus. Atopic diseases included asthma (23%), eczema (14%), and hay fever (30%). Only 9% wore contact lenses before referral. Mean follow-up was 1004 days ±282 (range, 390–1335) and 9.7±8.9 (range, 1.1–60) years from diagnosis. The mean simulated K1 corneal power at enrolment was 51.74±5.36 (range, 42.59–67.32) D and 88.5% exhibited bilateral keratoconus. Fifty-three (15%) topographically confirmed cones exhibited no clinical corneal signs at presentation. At enrollment, 56% had a pachymetry <0.480 mm increasing to 77% at final review. Forty-eight percent of subjects reported significant eye rubbing and there was a highly statistically significant difference (two sample t-test P=0.018) between keratoconus and control groups. TMS-2 axial corneal power was strongly associated with corneal scarring and age at diagnosis. The size of the scarring effect was 2.2 D (95% confidence interval (CI) 1.34, 3.06).ConclusionsThis study provides an overview of a large population with keratoconus highlighting presenting features and clinical and topographic progression over a 4 year-period.

Eye injuries in children: the current picture

AIMS To investigate the current causes and outcomes of paediatric ocular trauma. METHODS A prospective observational study of all children admitted to hospital with ocular trauma in Scotland over a 1 year period. RESULTS The commonest mechanism of injury was blunt trauma, accounting for 65% of the total. 60% of the patients were admitted with a hyphaema. Injuries necessitating admission occurred most frequently at home (51%). Sporting activities were the commonest cause of injury in the 5–14 age group. There were no injuries caused by road traffic accidents or fireworks. Patients were admitted to hospital for a mean of 4.2 days (range 1–25 days). One (1%) child had an acuity in the “visually impaired” range (6/18–6/60) and one (1%) was “blind” (6/60) in the affected eye. No child was bilaterally blinded by injury and none required blind or partial sight registration. CONCLUSION This study has shown that the incidence of eye injuries affecting children has fallen. The outcome of ocular trauma has improved significantly, and for the first time paediatric injuries appear to have a better prognosis than injuries affecting adults.

Incidence of cases of ocular trauma admitted to hospital and incidence of blinding outcome.

AIMS: To provide epidemiological data on the current burden of serious eye injuries utilising the hospital eye service, to inform the planning and provision of eye health care, and health and safety strategies for the prevention of ocular injuries. METHODS: A prospective observational study was carried out of all patients with ocular trauma admitted to hospitals in Scotland, under the care of a consultant ophthalmologist, during a 1 year period. The population of Scotland represented the population at risk of injury. Visual outcome (Snellen visual acuity in the injured eye) was measured at the time of final discharge from ophthalmic care and at follow up. RESULTS: All ophthalmic departments in Scotland participated and a total of 415 residents of Scotland were admitted. The 1 year cumulative incidence of ocular trauma necessitating admission to hospital is estimated to be 8.14 per 100 000 population (95% CI 7.38 to 8.97). Some 13.2% (n = 26/197) of patients discharged from follow up had a poor visual outcome with a visual acuity less than 6/12 in the injured eye. Some 10.7% (21/197) patients at this time had a blinding outcome in the injured eye (visual acuity less than 6/60). No patient was registered blind or partially sighted during the study period. The home was the single most frequent place for blinding injuries to occur (52%, n = 11/21), followed by the workplace 24% (n = 5/21). The 1 year cumulative incidence of blinding outcome from serious ocular trauma is estimated to be 0.41 per 100 000 population per year (95% CI 0.26 to 0.64). CONCLUSION: The current burden of serious ocular trauma presenting to the hospital eye service has been quantified from this population based study, and for the first time, a direct estimate of the incidence of the subsequent blinding outcome from these injuries has been provided. Ocular trauma remains an important cause of avoidable and, predominantly, monocular visual morbidity (visual impairment and blindness), with over half of the blinding injuries now occurring in the home. Health education and safety strategies should now consider targeting the home for the prevention of the serious eye injuries in addition to the traditional work, sports, and leisure environments and their related activities.

Effect of mydriasis and different field strategies on digital image screening of diabetic eye disease

Aims: To assess the effects of (1) mydriasis and (2) single versus three field photography on screening for diabetic eye disease using digital photography Method: Slit lamp examination findings were compared to digital fundal photographs for the detection of any retinopathy and for referable retinopathy in 398 patients (794 eyes). A Topcon TRC-NW6S digital non-mydriatic fundus camera was used. Three photographic strategies were used: undilated single field, dilated single field, and dilated multiple fields. The photographs were presented in random order to one of two retinal screeners. For the single field photographs the screeners were masked to the use of mydriatics. In 13% of fundal photographs, grading was performed by both, rather than just one grader. Results: Mydriasis reduced the proportion of ungradable photographs from 26% to 5% (p<0.001). Neither mydriasis nor three field photography improved the sensitivity or specificity for the detection of any retinopathy or of referable retinopathy when compared with undilated single field photography. The sensitivity and specificity for detecting referable retinopathy using undilated single field photography was 77% (95% CI 71 to 84) and 95 % (95% CI 93 to 97) respectively. Using dilated single field photography the figures were 81% (95% CI 76 to 87) and 92% (95% CI 90 to 94) respectively. Using dilated three field photography the figures were 83% (95% CI 78 to 88) and 93% (95% CI 91 to 96) respectively. Intergrader reliability for the detection of referable retinopathy in gradable photographs was excellent (Kappa values 0.86–1.00). Conclusions: Mydriasis reduces the technical failure rate. Mydriasis and the three field photography as used in this study do not increase the sensitivity or specificity of detecting diabetic retinopathy.

A systematic review of outcomes after dacryocystorhinostomy in adults.

Background This study was designed to systematically review the clinical outcomes of dacryocystorhinostomy (DCR) surgery. Data sources included PubMed for English language literature from January 1966 to December 2008 combined with a manual review of citations within article bibliographies. Methods Citations acquired from the targeted search were filtered independently by two researchers. Relevant articles were reviewed to obtain information including interventions and outcome measures. The surgical techniques were categorized into external DCR (EX-DCR), endonasal laser-assisted DCR (LA-DCR), and nonlaser endoscopic endonasal DCR techniques (EN-DCR). Articles were then assigned level-of-evidence grades as defined by the Oxford Center for Evidence-Based Medicine. Results A total of 73 studies that fulfilled the inclusion criteria were analyzed. Of these, 68 were graded as level 4, 11 were graded as level 3b, and 1 was graded at level 2b evidence. A total of 4800 patients were pooled, from which 4921 DCRs were performed. All studies reported success during the follow-up period, although the outcome measures used were not consistent in the studies. Success varied between 65 and 100% after EX-DCR compared with EN-DCR, which varied from 84 to 94%. The success rate of LA-DCR varied widely between 47 and 100%. There was low evidence base to support the use of silicone stent to improve surgical success. Most studies did not show significantly improved outcomes with an antimetabolite. The overall intra- and postoperative complication rates were 1.0 and 6%, respectively. Conclusions DCR is an effective and safe method for the treatment of nasolacrimal obstruction. Meta-analysis of outcomes was not feasible because of the heterogenous patient groups and outcome measures used. Nonetheless, the literature provides considerable levels 3 and 4 evidence to support DCR surgery in adults. Outcomes after EN-DCR and EX-DCR were comparable. The failure rate for LA-DCR was higher.

Epidemiology and implications of ocular trauma admitted to hospital in Scotland.

OBJECTIVES: To describe the current epidemiology of serious ocular trauma which necessitates admission to hospital so that health and safety strategies for the prevention of ocular injuries and their role within the national health strategy, The Health of the Nation, can be better informed. DESIGN: A prospective observational study of all patients with ocular trauma admitted to hospital under the care of a consultant ophthalmologist between 1 November 1991 and 31 October 1992. SETTING: All ophthalmic department in Scotland. SUBJECTS: All patients with ocular trauma admitted to hospital in Scotland. The population of Scotland represented the population at risk of injury. MEASURES AND MAIN RESULTS: Measures included the type and cause of injury, the place where it occurred, and awareness of risk and safety. All ophthalmic departments in Scotland participated and 428 admissions were reported. The home was the most common place for a serious injury to occur (30.2%), followed by the workplace (19.6%) and a sports or leisure facility (15.8%). The home was the single most frequent place of injury for the 0-15 year and 65 year and over age groups. Tools or machinery, either at home (13.9%) or at work (10.3%), were collectively (24.2%) the most frequent cause of injury, followed by assault (21.8%) and sports-related activities (12.5%). The most frequent type of injury was a blunt injury (54.4%). Six per cent (n = 25) of all injuries were bilateral. Only 13.2% of patients were aware of any risk of injury, with 5.6% aware of any risk at home. When applicable, protective eye wear was only available to 48.6% of patients and only 19.4% of these used it. CONCLUSION: Serious ocular trauma frequently occurs at home and the young and the elderly are particularly at risk. This represents a significant change in the epidemiology of serious ocular trauma and has important implications for prevention. Health and safety strategies specifically aimed at preventing eye injury should now include the home as a high risk environment in addition to the work-place and sports/leisure facilities. The target groups for accident prevention in The Health of the Nation strategy include those at risk of serious ocular trauma with potentially sight threatening sequelae. Those involved in implementing the national accident prevention strategy should be aware of this, for in this process it is possible that some serious eye injuries may also be prevented.

Factors influencing visual outcome in anisometropic amblyopes

Aim: To identify which factors influence the final visual acuity in children with anisometropic amblyopia. Methods: A retrospective analysis of 112 children with anisometropic amblyopia, identified from examining all case notes of children who had failed preschool or school screening. Results: The age at presentation had no effect on the final visual outcome (p=0.804). Both the degree of refractive error and the degree of anisometropia at presentation correlated with final visual acuity (p<0.001 and p=0.001). Those with strabismus had a poorer final outcome. Conclusions: The age at presentation of a child with anisometropic amblyopia appears to have no significant effect on the final visual acuity. The amount of refractive error and degree of anisometropia at presentation do correlate strongly with final visual acuity. This would suggest, firstly, that children with poorer visual acuity at presentation and higher degrees of anisometropia should be treated more aggressively and that, secondly, children with anisometropic amblyopia should be treated regardless of age.

A systematic review of outcomes following surgical decompression for dysthyroid orbitopathy

To systematically review and compare the surgical outcomes of orbital decompression for dysthyroid orbitopathy.

Ocular sports injuries: the current picture

Objectives—To determine the recent incidence of eye injury due to sport in Scotland, identify any trend, and establish which sports are responsible for most injury? The type of injury and final visual outcome is also evaluated. Methods—A prospective observational study of ocular injuries sustained during sport was performed over a one year period. Only patients requiring hospital admission were included. Data were collected on a standardised proforma and entered into a central database. Patients were followed up for at least three months. Results—Of 416 patients admitted because of ocular injury, 52 (12.5%) resulted from playing a sport. Although all racquet sports together accounted for 47.5% of these injuries, football was the single most common sport associated with ocular trauma, being responsible for 32.5% of cases. The most common clinical finding was macroscopic hyphaema occurring in 87.5% of patients. Overall the final visual acuity was 6/6 in 92.5% of patients. Conclusions—The incidence of eye injury due to sport at 12.5% is lower than previously reported, suggesting a change in the pattern of ocular trauma. Football is the single most common cause of ocular injury from sport in Scotland, but the wearing of protective headgear would be difficult to instigate. The incidence of hyphaema in sport related ocular trauma (87.5%) is almost double that of all ocular injury (47.8%), so the potential for serious visual loss as the result of a sports injury should not be underrated. Ophthalmologists have a role in protecting this young population at risk by actively encouraging the design and use of protective eyewear.

Quantitative analysis of corneal microstructure in keratoconus utilising in vivo confocal microscopy.

PurposeTo establish and quantify the in vivoconfocal microscopic features of moderate to advanced keratoconus.MethodsNineteen keratoconus subjects were catergorised using Orbscan-derived corneal apex power and pachymetry as exhibiting moderate (n=7) and advanced (n=12) keratoconus. Control subjects included 23 noncontact lens wearers (Group A) and 15 contact lens wearers (Group B). All subjects underwent Confoscan slit scanning in vivoconfocal microscopy.ResultsCompared with Group A (4912±434 cells/mm2), basal epithelial density was significantly lower in both moderate (4592±414 cells/mm2, P<0.05) and advanced keratoconus (4530±596 cells/mm2, P=0.01). In comparison to Group A (761±118 cells/mm2), anterior stroma keratocyte density was significantly greater in both moderate keratoconus (883±111 cells/mm2, P=0.001) and advanced keratoconus (952±122 cells/mm2, P<0.001). Compared to Group A (504±80 cells/mm2) posterior stroma keratocyte density was also significantly greater in advanced keratoconus (599±97 cells/mm2, P<0.001) and posterior stromal keratocyte density appeared to increase with increasing severity of keratoconus (P<0.05). However, comparing control Groups A and B, contact lens wear per se, was associated with significantly reduced (P=0.000) keratocyte density in the anterior stroma (609±66 cells/mm2) and demonstrated a trend (P=0.056) in the posterior stroma (470±63 cells/mm2). Keratoconic corneas (429±72 μm) were significantly thinner than control Groups A (508±77 mm) and B (495±80 μm). The presence of keratoconus did not affect the endothelial cell density (P=0.54).ConclusionIn vivoconfocal microscopy can provide insight into the microstructural changes that occur in keratoconus.