Preliminary results from the use of the novel Interactive binocular treatment (I-BiT) system, in the treatment of strabismic and anisometropic amblyopia.

BACKGROUND: We have developed a novel application of adapted virtual reality (VR) technology, for the binocular treatment of amblyopia. We describe the use of the system in six children. METHODS: Subjects consisted of three conventional treatment 'failures' and three conventional treatment 'refusers', with a mean age of 6.25 years (5.42-7.75 years). Treatment consisted of watching video clips and playing interactive games with specifically designed software to allow streamed binocular image presentation. RESULTS: Initial vision in the amblyopic eye ranged from 6/12 to 6/120 and post-treatment 6/7.5 to 6/24-1. Total treatment time was a mean of 4.4 h. Five out of six children have shown an improvement in their vision (average increase of 10 letters), including those who had previously failed to comply with conventional occlusion. CONCLUSIONS: Improvements in vision were demonstrable within a short period of time, in some children after 1 h of treatment. This system is an exciting and promising application of VR technology as a new treatment for amblyopia.

Modified virtual reality technology for treatment of amblyopia.

PURPOSE: The conventional patching/occlusion treatment for amblyopia sometimes gives disappointing results for a number of reasons: it is unpopular, prolonged, frequently resulting in poor or noncompliance, and also disrupts fusion. The aim of this research was to develop a novel virtual-reality (VR)-based display system that facilitates the treatment of amblyopia with both eyes stimulated simultaneously. METHODS: We have adopted a multidisciplinary approach, combining VR expertise with a team of ophthalmologists and orthoptists to develop the Interactive Binocular Treatment (I-BiT) system. This system incorporates adapted VR technology and specially written software providing interactive 2D and 3D games and videos to the patient via a stereo (binocular) display, and a control screen for the clinician. RESULTS: We developed a prototype research system designed for treatment of amblyopia in children. CONCLUSIONS: The result is a novel way to treat amblyopia, which allows binocular treatment. It is interactive, and as it is partially software based, can be adapted to suit the age/ability, and needs of the patient. This means that the treatment can be made captivating and enjoyable. Further research is on-going to determine the efficacy of this new modality in the treatment of amblyopia.

Infective keratitis in older patients: a 4 year review, 1998-2002.

BACKGROUND/AIM: There are few clinical series in the literature of infective keratitis in the elderly, even though this age group constitutes a significant proportion of those affected by this condition. The authors aimed to determine the incidence and risk factors for infective keratitis in those over 60 years, the causative organisms, antibiotic susceptibilities, visual and tectonic outcome, and surgical intervention rate. METHODS: A retrospective review of all patients aged 60 years and over admitted to the Sydney Eye Hospital with a diagnosis of infective keratitis, between September 1998 and December 2002. RESULTS: 190 patients were identified with a mean age of 75.5 (SD 9.6) years (range 60-101). Local risk factors were found in 93.7%, and systemic risk factors in 27.9%. Organisms were cultured in 62.8%, and 7.9% had positive herpes simplex virus (HSV) polymerase chain reaction (PCR). Perforation or severe thinning occurred in 36% overall, but in 80% with positive HSV PCR. Acute surgical intervention was required in 43.7%, with acute penetrating keratoplasty performed in 17.9%, and 8.9% required evisceration. Mean presenting visual acuity was 1.82 (SD 1.24), equivalent to 6/300, excluding 26.3% with vision of light perception (LP) or worse. Mean final visual acuity was 1.24 (SD 1.16), equivalent to 6/100, excluding 19.5% with vision of LP or worse (p<0.0005). CONCLUSIONS: The elderly represent a distinct clinical group in the context of microbial keratitis. Predisposing factors are very common, they present with poor vision, have a high complication and surgical intervention rate, and a poor visual outcome compared to younger patients. The microbiological spectrum is similar to younger age groups, except that HSV is more common and may increase the risk of severe corneal thinning and perforation. Most bacterial isolates remain sensitive to currently available antibiotic preparations.

Anatomical and visual outcome of retinal detachment surgery in children.

AIMS: To evaluate the visual and anatomical outcome, as well as complications following surgery, for rhegmatogenous retinal detachment in children at a tertiary referral centre over a 5 year period. METHODS: A retrospective survey of all children (aged 0-16 years) who underwent primary retinal detachment surgery at Queen's Medical Centre between April 1994 and March 1999. RESULTS: 15 consecutive patients were identified with a mean follow up of 14.7 months (range 3-57) and a mean age of 12.4 years. Trauma was the cause in 40% (6/15). Complete retinal reattachment was achieved in 86.6% (13/15). Visual improvement occurred in 53.3% (8/15), worsening of vision occurred in 13.3% (2/15), with no change in the remaining 33.3% (5/15). Visual acuity was D 6/12 in 6.6% (1/15) preoperatively, and 26.6% (4/15) postoperatively. CONCLUSIONS: Retinal detachment in children is rare compared with adults. There are therefore limited data available for this group of patients. These data provide one unit's experience over a 5 year period, and may help provide a basis for information for patients and their parents when discussing the risks and potential benefits of surgery for retinal detachment in the paediatric population.

In vitro model of infectious crystalline keratopathy: tissue architecture determines pattern of microbial spread.

PURPOSE: To develop an in vitro model of infectious crystalline keratopathy using human corneal buttons and to test the hypothesis that the compactness of the corneal stroma determines the pattern of microbial spread. METHODS: Twenty human corneal buttons obtained after penetrating keratoplasty for keratoconus (KC) and eight human corneal buttons obtained from eye bank (EB) donor eyes were maintained in organ culture. Fourteen buttons (10 KC and 4 EB donors) were maintained in a turgid state (swollen, edematous) and 14 in a nonturgid state (compact, normal state of deturgescence) by the omission or addition of 5% dextran to the culture medium. Eight KC and four EB nonturgid buttons and eight KC and four EB turgid buttons were inoculated with Streptococcus viridans (Lancefield group G, gram-positive) organisms. Two KC nonturgid and two KC turgid buttons were inoculated with Klebsiella oxytoca (gram-negative) organisms. Bacterial migration and spread in the tissue were observed by light and electron microscopy. RESULTS: Of the nonturgid buttons, six KC buttons and all four EB buttons inoculated with S. viridans and both KC buttons inoculated with K. oxytoca demonstrated an arborizing, crystallike pattern of bacterial spread. In the turgid buttons, five KC and all four EB buttons inoculated with S. viridans and both KC buttons inoculated with K. oxytoca demonstrated globular, amorphous colonies. This was in complete contrast to the needlelike branching appearance seen in nonturgid corneal buttons. Electron microscopy confirmed an interlamellar spread of the bacterial colonies. CONCLUSIONS: This is the first in vitro model of bacterial keratitis. It demonstrates that the pattern of spread of bacteria within corneal tissue is largely determined by the compactness of the corneal stroma. Altering tissue architecture changed the pattern of bacterial migration and spread. This model has considerable potential in further understanding host-microbe interactions and microbial spread that occurs during infection.

Non-enhanced trabeculectomy by non-glaucoma specialists: are results related to risk factors for failure?

PURPOSE: To determine the 1 year success rate of non-enhanced trabeculectomy under the care of non-glaucoma specialists and the effects of risk factors on the surgical outcome as measured by intraocular pressure (IOP) control. METHODS: A retrospective study of 167 patients undergoing trabeculectomy was performed. One hundred and four cases were performed in a teaching hospital and 63 in a district general hospital (DGH). Non-glaucoma specialists performed all the operations, enhanced trabeculectomy with antimetabolites being excluded. Information was recorded from a retrospective review of case notes, and post-operative IOPs at 12 months follow-up were analysed. Risk factors for failure were defined as: (1) age less than 40 years old, (2) black race, (3) diabetes mellitus, (4) miotic therapy > or = 18 months, (5) sympathomimetic therapy > or = 6 months, (6) pseudophakia or aphakia, (7) previous failed filtration procedure, (8) argon laser trabeculoplasty, (9) previous ocular surgery and (10) high-risk glaucoma (angle recession glaucoma, uveitic glaucoma and neovascular glaucoma). A success was defined to be a post-operative IOP at 1 year of less than 21 mmHg and at least 20% less than the presenting IOP on no medication. RESULTS: The overall success rate was 139 of 167 (83.2%). Eighty-seven of 104 eyes (83.7%) were classified as a success in the teaching hospital group and 52 of 63 (82.5%) were classified as a success in the DGH group. There was no significant difference in the number of risk factors between the success and failure groups. Eyes with two or more risk factors had significantly higher IOPs at 1 year when compared with eyes with 0 or 1 risk factor (mean +/- SD: 17.4 +/- 6.34 mmHg vs 14.2 +/- 5.0 mmHg, p = 0.022). When only 'successful eyes' were analysed, those with two or more risk factors still had significantly higher IOPs at 1 year (mean +/- SD: 15.0 +/- 3.0 mmHg vs 12.8 +/- 3.9 mmHg, p = 0.046). There were significantly fewer eyes in the two or more risk factor group with IOPs < 16 mmHg at 1 year (26.1% vs 60.4%, p = 0.021). CONCLUSIONS: Eyes at relatively low risk for failure operated upon by non-glaucoma specialists appeared to have success rates similar to previously published series. Eyes with two or more risk factors for failure have higher IOPs at 1 year in non-enchanced trabeculectomy. Adjunctive anti-scarring agents may be considered for these patients when filtration surgery is scheduled.

Assessment of the Heidelberg Retina Tomograph in the detection of sight-threatening diabetic maculopathy.

PURPOSE: To assess the potential role of the Heidelberg Retina Tomograph (HRT) in screening for sight-threatening macular oedema in diabetes. METHODS: One hundred and thirty-one eyes of 81 consecutive diabetic patients who fitted the inclusion criteria were included in the study. On HRT, the volume above the reference plane bound within a 2 mm diameter circle centred at the fovea was measured. The volumetric indices were compared with the mean measurement index in a group of 20 age-matched controls (mean score = 1, mean +2 SD score = 1.8). We also assessed the sensitivity of the subjective analysis of the intensity image and the addition of the three-dimensional map to the intensity image for detecting macular oedema and clinically significant macular oedema (CSMO). RESULTS: One hundred and twelve eyes of 71 patients had a corrected Snellen visual acuity of 6/9 or better. When considering eyes with 6/9 or better vision only, the system's sensitivity for detecting CSMO was 58.33% 'per eye' examined, and 81.82% 'per patient' examined using a cut-off volumetric index of 1.8. In our study eyes with 6/9 or better vision, we found a 21% prevalence of CSMO. The predictive values of a positive test were 38.89% and 45% (cut-off score 1.8, 'per eye' and 'per patient' respectively) for CSMO. The predictive values of a negative test were 86.84% and 90.48% (cut-off score 1.8, 'per eye' and 'per patient' respectively) for CSMO. CONCLUSIONS: The volumetric assessment of diabetic maculopathy by HRT is a potentially useful method for screening eyes at risk. A larger group of patients with a greater number of eyes with minimal or no maculopathy is required to establish the specificity of this technique.