Rarebit Perimetry Research Articles

Flicker defined form and RareBit measurements lack in specificity of visual pathways.

To evaluate the different visual pathways represented by the Heidelberg Engineering Perimeter flicker defined form and RareBit (magnocellular and parvocellular respectively) in different age-groups and according to the fatigue. Totally 64 eyes of 32 healthy subjects were included in the prospective study. Each participant underwent screening-ophthalmic examination including best-corrected visual acuity, anterior and posterior segment assessment, and visual field examination with Heidelberg Edge Perimetry (HEP)-standard automated perimeter (SAP) 24-2. They were observed for 2y previously to the enrollment. This helped to define that the enrolled patients did not bear the glaucoma-developing potential. During the screening and after two years the HEP had been conducted in the standard protocol 24-2 and RareBit perimetry (RBP) in accordance with the manufacturer's description. Participants were randomly assigned to the groups: flicker defined form (FDF)-first or RBP-first. This defined from which additional visual field test the participant started. Participants were additionally subdivided to younger and older study groups. The effect of subject variables was explored with Mann-Whitney U-test. Testing for the presence of correlations between parameters was performed using the Spearman Rank Order Correlations and confirmed by the parametric tests. For the influence of additional factors, the Kruskal-Wallis test was performed. The positive correlation between mean deviation (MD) and mean hit rate (MHR) and pattern standard deviation (PSD) and standard deviation of MHR (±MHR) were found in younger study group (P=0.005, r=0.481 and P=0.0074, r=0.465), whereas in the older subgroup no correlation was observed. Additionally, the randomization protocol helped in defining the role of fatigue on the HEP-FDF results. Participant for whom the HEP-FDF was performed after RareBit had significantly worse results than those for whom the HEP-FDF was first. In the younger group, the MHR and ±MHR depend from age in that group (P<0.05, r=0.43 and r=-0.57 respectively) while no age-dependent differences were found in HEP-related parameters. On the contrary in the older group the MD and PSD varies with age (P<0.05, r=0.47 and r= -0.44 respectively) while the RBP parameters remained unchanged. The questionnaire showed that participants preferred RareBit over HEP-FDF in terms of a duration time, comfort, understanding of the test procedures, and ocular pain (P<0.05). The influence of patient's fatigue should be considered during HEP-FDF examination. An overlap hypothesis should be reevaluated after determining of other factors that affect HEP-FDF and RareBit results.

Multidimensional Functional and Structural Evaluation Reveals Neuroretinal Impairment in Early Diabetic Retinopathy.

PurposeTo test whether quantitative functional tests and optical coherence tomography (OCT)-defined structure can serve as effective tools to diagnose and monitor early diabetic neuroretinal disease.MethodsFifty-seven subjects with diabetes (23 without diabetic retinopathy [no DR], 19 with mild nonproliferative diabetic retinopathy [mild NPDR], 15 with moderate to severe [moderate NPDR]), and 18 controls underwent full ophthalmic examination, fundus photography, spectral-domain optical coherence tomography (SD-OCT), e-ETDRS (Early Treatment Diabetic Retinopathy Study) acuity, and the quick contrast sensitivity function (qCSF) method. Perimetry testing included short-wavelength automated perimetry (SWAP), standard automated perimetry (SAP), frequency doubling perimetry (FDP), and rarebit perimetry (RBP).ResultsETDRS acuity and RBP were not sensitive for functional differences among subjects with diabetes. AULCSF, a metric of qCSF, was reduced in diabetics with moderate compared to mild NPDR (P = 0.03), and in subjects with no DR compared to controls (P = 0.04). SWAP and SAP mean deviation (MD) and foveal threshold (FT) were reduced in moderate compared to mild NPDR (SWAP, MD P = 0.002, FT P = 0.0006; SAP, MD P = 0.02, FT P = 0.007). FDP 10-2 showed reduced MD in moderate compared to mild NPDR (P = 0.02), and FDP 24-2 revealed reduced pattern standard deviation (PSD) in mild NPDR compared to no DR (P = 0.02). Structural analysis revealed thinning of the ganglion cell layer and inner plexiform layer (GCL+IPL) of moderate NPDR subjects compared to controls. The thinner GCL+IPL correlated with impaired retinal function.ConclusionsThis multimodal testing analysis reveals insights into disruption of the neuroretina in diabetes and may accelerate the testing of novel therapies.

Parallel rarebits: A novel, large‐scale visual field screening method

BackgroundRarebit perimetry () is a computer‐based perimetric testing program with sensitivity and specificity for detection of visual field defects comparable to traditional automated perimetry. To make large‐scale screening more efficient, we developed a parallel rarebit perimetric method to screen groups of subjects simultaneously. We then used this method to report the mean hit rate (MHR) among subjects aged 13 to 19 years.MethodsRarebit perimetry was installed on computers in an existing school computer laboratory. All subjects provided medical and demographic information and underwent a basic visual examination. Testing instructions were provided to groups of up to 35 subjects and rarebit perimetry was subsequently administered. Two or three test supervisors answered questions and ensured that subjects were well aligned with their test screens. Mean hit rate, reaction times, error rates and testing time were calculated, and time estimates for rarebit, frequency doubling perimetry and Humphrey 24‐2 Swedish Interactive Thresholding Algorithm (SITA) fast test were compared.ResultsA total of 364 rarebit perimetric tests were conducted on 182 subjects. Of these, 154 subjects met our inclusion criteria for the reference range (three testing errors or less and visual acuity 6/9 or better). The average mean hit rate was 94.3 ± 4.63 per cent. Screening of 500 subjects using this parallel rarebit perimetric method would require approximately nine hours, which is far less than an estimated 77 hours required for frequency doubling perimetry ‐20 screening tests or an estimated 127 hours required for Humphrey 24‐2 SITA fast tests.ConclusionUsing our methods, rarebit perimetry can be administered in parallel to groups of subjects. The mean hit rate was comparable to that reported in previously published studies. This parallel technique may improve the efficiency of large‐scale visual field screenings.

Clinical guidelines for diagnosing and managing ocular manifestations in children with mucopolysaccharidosis

The mucopolysaccharidoses (MPS) are a group of rare lysosomal storage disorders characterized by the accumulation of glycosaminoglycans in several tissues and organs. This accumulation results in an array of clinical manifestations and premature death in severe cases. Ocular problems are very common in children with MPS and may involve the cornea, sclera, trabecular meshwork, retina, optic nerve and also the posterior visual pathways. The aims of this study are to give an overview of ocular problems in MPS and to provide clinical guidelines for paediatric ophthalmologists for early diagnosis and management of ocular manifestations in children with MPS. Diagnostic problems may arise in children with severe corneal clouding, hampering visualization of the fundus. Intraocular pressures may be falsely high, even leading to suspicion and unnecessary pressure-lowering treatment. Simple interventions such as the use of prescription glasses or photochromatic glasses can considerably improve quality of life in children with MPS.

Variability of Rarebit and Standard Perimetry Sizes I and III in Normals

To compare test-retest variability in rarebit perimetry (RBP) and conventional standard automated perimetry (SAP) using Goldmann size I and III stimuli. Seventeen normal subjects underwent RBP, size I SAP, and size III SAP on five separate visits within a 5-week period. Test-retest variability could not be directly compared because of differences in units. Instead, data were transformed to lie on the same scale by calculating a percentile range to mean ratio for each test. Percentile range to mean ratio was highest for size I (3.42 ± 0.62), followed by size III (2.29 ± 0.55), and RBP (0.29 ± 0.10). Results for all three tests were significantly different from each other. Comparison of tests with different scales is problematic, but RBP's retest variability appears to be significantly less than both sizes I and III SAP in the measurement of normal subjects.

Rarebit perimetry: normative values and test-retest variability

We aim to establish normative values and evaluate test-retest variability for the central and foveal field tests of version 4 of rarebit perimetry. This was a prospective study undertaken in collaboration between Tan Tock Seng Hospital, Singapore, and Singapore Polytechnic. Fifty-four normal subjects were recruited and included in the study. Subjects underwent rarebit perimetry testing, studying the central and foveal fields. All subjects repeated the test within 1 month of the initial visit. The 'mean hit rates' of one eye of every subject were analysed. Mean hit rates of subjects were analysed to establish normative values for the central and foveal fields. Test-retest variability was also analysed. Overall normative mean hit rates were 86.3 ± 13.95% for the central field and 91.6 ± 6.35% for the foveal field. For every increasing year of age, we found a 0.47% decrease in the central mean hit rates (P < 0.001). Normative mean hit rate for central and foveal fields were 90.6 ± 12.3% and 98.2 ± 3.7% respectively, in 'young' subjects, and 81.9 ± 15.6% and 85.0 ± 9.0% respectively, in 'mature' subjects. We found no significant test-retest variability in the foveal field (P = 0.554). There was significant test-retest variability in the central field (P < 0.001), but the difference was a 3.5 unit mean hit rate increase, which may be clinically significant. Rarebit perimetry is repeatable and reliable. We have established normative values for two age groups.

Occurrence and pattern of ocular disease in children with cholestatic disorders

To describe visual function and ocular manifestations in patients with onset of cholestasis during the neonatal period. Patients with neonatal cholestasis, either transitory or chronic, who came for assessment to our tertiary referral centre were included in a cross-sectional study and underwent ophthalmological examinations including fundus photography. A total of 57 patients (24 girls and 33 boys), aged 0.4-18.0 years, were included. Of these, 28 patients had biliary atresia, 11 had Alagille's syndrome, five had progressive familiar intrahepatic cholestasis and nine had different disorders such as pituitary insufficiency, alpha-1-antitrypsin deficiency, mitochondriopathy, congenital infections or cholestasis caused by unknown reasons. Visual dysfunction and/or one or several ocular manifestations occurred in 39 out of 57 patients. Major ocular malformations occurred in five patients. Out of three patients with biliary atresia, one patient had severe visual impairment caused by microphthalmia and chorioretinal coloboma, one patient with Cat Eye syndrome had bilateral uveochorioretinal coloboma and one patient had Rieger's anomaly. Two patients, both with pituitary deficiency and transient cholestasis, had severe unilateral visual impairment caused by optic nerve hypoplasia. The majority (68%) of the patients with cholestasis had ocular manifestations. Although the severity of ocular complications varied with diagnosis, and was most apparent among patients with biliary atresia or pituitary deficiency, no conclusion can be drawn regarding the connections between these conditions from the present study. Nevertheless, ocular assessment is important for diagnostic purposes and for early intervention in patients with cholestasis.

Determining Mechanisms of Visual Loss in Glaucoma Using Rarebit Perimetry

Evidence for ganglion cell visual dysfunction in human glaucoma is often indirect, being either measured at the cellular level in animal models or being inferred from the pooled responses of a large number of ganglion cells in human observers. Rarebit perimetry (RBP) uses repeated, intense (150 cd/m2) stimuli-whose size is close to the spatial scale of a ganglion cell-to search for small retinal areas with zero sensitivity. Decreasing the stimulus luminance to 64 cd/m2 in normal observers does not alter the percentage of RBP stimuli detected [the mean hit rate (MHR)], and so we hypothesized that a similar response robustness should occur in glaucoma if the elements detecting the RBP target show no signs of visual dysfunction. Nineteen glaucoma subjects and 19 age-matched controls were tested with a customized RBP test at 13 stimulus luminances (10 to 150 cd/m2, 0.14 log unit intervals). A four-parameter (threshold, spread, false positive proportion, and miss rate) cumulative Gaussian psychometric function was fitted to the response rate data from a glaucoma-affected region (glaucoma subjects; MHR >50% and <80%) and from the corresponding region in an age-matched normal control. Our hypothesis would predict that only the miss rates should differ between groups. Glaucoma subjects showed significantly higher miss rates (0.18 vs. 0.04, p < 0.001), lower false positive proportions (0.009 vs. 0.025, p = 0.004), greater spreads (0.30 vs. 0.19, p = 0.002), and elevated thresholds [1.57 log(cd/m2) vs. 1.13 log(cd/m2), p < 0.001]. Responses to RBP stimuli are not robust to decreasing luminances in glaucoma. Our results more directly imply the presence of ganglion cell visual dysfunction in human glaucoma than studies using larger targets where contrast sensitivity losses could result through ganglion cell death alone. Such dysfunction may not be detected by Rarebit's MHR given that dysfunctional elements may still respond to the very intense RBP stimulus.

The role of standard automated perimetry and newer functional methods for glaucoma diagnosis and follow-up

Automated perimetry has become the mainstream for assessment of functional glaucomatous loss and progressive damage. Recent improvements with the Swedish interactive thresholding algorithm (SITA) strategy and the guided progression analysis (GPA) have further settled standard achromatic perimetry (SAP) as the preferred method for diagnosis and follow-up of functional loss. Although SAP is still considered the gold standard, function-specific perimetry may offer advantages for early diagnosis. Frequency doubling technology (FDT) and short-wavelength automated perimetry (SWAP) have been shown to be helpful, especially when SAP is normal and there is a suspicion of glaucoma. Studies using rarebit perimetry have also shown promising results. Studies have observed that each test identifies a different subset of eyes, and combining the tests may improve sensitivity. Nevertheless, the more sophisticated analyses do not reduce the importance of a correct interpretation of the test results.

Perimetry and imaging in glaucoma diagnosis: a pilot study

Aim: To compare the findings from Humphrey Matrix and Rarebit (RB) perimetry in relation to the results from Heidelberg confocal laser scanning retina tomography (HRT II). Material: Data from 22 eyes (12 subjects, age 51–75 years) with known or suspected glaucoma were analyzed. Methods: The central 30° visual field was examined with two perimetric techniques; Humphrey Matrix, using frequency doubling technology, and the RB test, relying on the detection of very small bright dots on a dark background. In addition, all subjects underwent laser scanning tomography of the optic nerve head. Results: There was no significant difference regarding the number of normal/abnormal findings between Humphrey Matrix and RB perimetry (9/22 and 8/22, respectively). Abnormal glaucoma index from the HRT II was observed in 5/22 eyes. In four of these, both Humphrey Matrix and RB perimetry were abnormal. In one eye both with abnormal HRTII, both perimetric tests were normal. Conclusion: This pilot study indicates that the studied perimetric methods appear to give equivalent results in glaucoma, despite the considerable difference in test principles.

Rarebit Perimetry for Bedside Testing: Comparison With Standard Automated Perimetry

Rarebit perimetry (RBP), a technique developed for the detection of early damage to the afferent visual system, has not been extensively tested at the bedside. This study was designed to test the feasibility of bedside testing with RBP in comparison with standard automated perimetry (SAP) performed in the clinic. We tested 29 eyes of 15 subjects admitted with neurologic or neurosurgical diseases affecting the afferent visual system. RBP was performed on a laptop computer at the bedside. SAP (Humphrey field analyzer) testing was performed later in the clinic. Results were evaluated by a masked neuro-ophthalmologist. Visual fields corresponded between RBP and SAP in 21(72%) of the 29 tested eyes. RBP detected defects in 5 subjects who had normal visual field results on SAP. All subjects preferred RBP for convenience. RBP is a convenient method of bedside visual field testing and is no less sensitive to visual field defects in this role than SAP.

Rarebit Perimetry in the Evaluation of Visual Field Defects in Idiopathic Intracranial Hypertension

Rarebit perimetry (RBP) is a new perimetric technique that has been reported as a sensitive test for the evaluation of the neural structure of the visual system. The aim of this study was to compare RBP with standard automated perimetry in detecting the visual field defects of patients with idiopathic intracranial hypertension (IIH). Twenty-five patients with IIH and 16 healthy controls were considered. Visual fields were analyzed with Marco automated static perimeter with threshold and central 30-2 programs (MP 30-2) and rarebit perimetry. A visual field was classified into 3 zones for both tests as central, paracentral, and peripheral zones. Mean sensitivity (MS) recorded by the MP 30-2 was compared with the mean hit rate (MHR) recorded by RBP for each zone. MS recorded by MP 30-2 and MHR recorded by RBP for each zone were significantly lower in the IIH group than in healthy control eyes (p < 0.001). Good correlation was present between the visual fields recorded by both tests. Although the sensitivity and specificity values for each zone were lower in the RBP group than the MP 30-2 group, RBP was found to be efficient to differentiate between the visual fields of normal and IIH-affected eyes. The average RBP test duration was significantly shorter than the MP 30-2 test duration (p < 0.001). CONCLUSIONS. RBP is a rapid, comfortable, and widely accessible perimetric test giving reliable results in detecting visual field defects in IIH.

Foveal function in children treated for amblyopia

This study aimed to evaluate foveal function, using three different methods, in children treated for monocular amblyopia. A sample of 24 otherwise healthy children with treated amblyopia and an age-matched control group of 25 healthy children were examined for best corrected visual acuity (BCVA) using a standard decimal (KM) chart and the computerized TriVA method at 50% and 10% contrasts. Foveal function was also measured with the rarebit fovea test (RFT), which is included in the rarebit perimetry program package. This test uses very small and bright dots against a dark background. The result is expressed as mean hit rate (MHR). Amblyopic eyes showed significantly lower BCVA when evaluated with the KM chart and with the TriVA test at different contrast levels, compared with both fellow eyes and control eyes. No statistically significant difference between amblyopic and fellow eyes was found when foveal function was evaluated with the RFT (median MHRs 91.5% and 94.5%, respectively), although results for both amblyopic and fellow eyes were statistically lower than those of the control group (median MHR 97%) (p = 0.001 and p = 0.046, respectively). This might indicate that the RFT provides different information about foveal function than conventional VA tests. The findings in the current study accord with those of other studies reporting abnormalities in the fellow eyes of previously treated amblyopic patients. These findings may reflect a general disturbance in the visual system rather than a monocular adaptation to refractive error or ocular motor disturbance.

Visual fields and optic disc morphology in very low birthweight adolescents examined with magnetic resonance imaging of the brain

We aimed to evaluate visual fields (VFs) and optic disc morphology in very low birthweight (VLBW) adolescents compared with age- and gender-matched controls, and to relate the findings to magnetic resonance imaging (MRI) results. Fifty-nine VLBW adolescents and 55 age- and gender-matched controls with normal birthweight were examined. Visual fields were tested using computerized rarebit perimetry (RB). Optic nerve and retinal vessel morphology were evaluated by digital image analysis of fundus photographs. Brain MRI was conducted in the VLBW subjects. Ten of the 57 VLBW subjects (p = 0.022) had subnormal VF results defined as a mean hit rate below the fifth percentile of the controls (i.e. < 89%). All of these also had significantly lower mean hit rates (p = 0.039) in the inferior hemifield. Sixteen of 57 (28%) VLBW subjects had white matter damage of immaturity (WMDI) on MRI. Six of 15 subjects with WMDI (who underwent VF testing) also had subnormal RB results, compared with four of 39 with normal MRI findings (p = 0.02). The mean neural retinal rim area was 9% smaller (p = 0.018) in the VLBW group than in the control group. The VLBW adolescents had a significantly higher index for tortuosity of arterioles than the controls (p < 0.001). In the present study, 18% of all VLBW adolescents and 40% of those with WMDI had subnormal RB VF findings. The VLBW group had increased arterial tortuosity and a somewhat smaller (9%) mean neural retinal rim area than the control group. Thus sequels to VLBW appear to persist in adolescence.

Non-conventional perimetric methods in the detection of early glaucomatous functional damage

To compare the ability of frequency-doubling technology (FDT), rarebit perimetry (RBP), and pulsar perimetry (PP) in detecting early glaucomatous functional damage. This prospective observational cross-sectional case study included 52 patients with early primary open-angle glaucoma (mean deviation -2.3+/-1.1 dB; pattern standard deviation 3.0+/-1.2 dB) and 53 healthy controls. Visual field (VF) testing included standard automated perimetry (SAP) Humphrey Field Analyzer 30-2, FDT N-30, RBP (version 4.0), and PP T30W. One eye per patient was considered. Sensitivity at fixed specificities and area under the receiver operating characteristic curve (AROC) for discriminating between healthy and glaucomatous eyes were calculated and compared. The parameters associated with the largest AROC, which were not statistically different (Hanley-McNeil method, P0.42-0.71) were as follows: number of locations in the pattern deviation probability (PDP) plot with P<5% for FDT (0.93); mean hit rate for RBP (0.95); and mean defect for PP (0.94). PP test duration was significantly shorter than FDT and RBP (P<0.002). FDT, PP, and RBP are useful non-conventional VF methods in detecting early glaucomatous VF defects with similar AROCs. The methods were rapid and easy, and PP took less than half the time than SAP. These non-conventional testing may prove to be useful in providing additional information in the diagnosis of glaucoma suspect with normal SAP results, in the therapeutic decision-making process of early glaucomatous patients, and in subjects unable to perform VF testing with SAP.

Rarebit perimetry and fovea test before and after cataract surgery

To evaluate the effect of cataract on rarebit perimetry and the fovea test. Twenty-five consecutive patients scheduled for cataract surgery (mean age 63.0 +/- 7.9 years) were examined prior to and after cataract surgery with a complete ophthalmological examination. In addition, the rarebit perimetry (RBP) and the rarebit fovea test (RFT) were performed. Best-corrected visual acuity [BCVA, expressed in minimum angle of resolution (MAR)], RBP and RFT mean hit rate (MHR) improved significantly after cataract surgery. The relative pre-postsurgery difference was larger in the RFT [2.1 standard deviations (SDs)] compared to in BCVA (0.78 SDs). Seven patients had good BCVA (< or = 1.25) and RBP (83-99%) but low RFT (0-66%) before surgery. One patient with low preoperative BCVA (2.5) had a normal RFT (94%). Cataract influenced both the RFT and RBP test, albeit the former more than the latter. The influence of cataract on RFT results, even when visual acuity is decreased only moderately, has to be taken into account when evaluating foveal function in patients with cataract. The larger relative change in RFT compared to BCVA values is thought to indicate that RFT is more sensitive for the effect of cataract. Therefore, RFT appears to be a sensitive test for visual disturbance and can presumably provide additional information at the preoperative evaluation of the patient.

The relationship between Rarebit perimetry and OCT‐derived retinal nerve fibre layer thickness in glaucoma

To examine the association between measures of neuroretinal matrix integrity as determined with Rarebit perimetry and optical coherence tomography (OCT)-derived retinal nerve fibre layer thickness. One randomly selected eye of 30 White primary open-angle glaucoma patients (age: 60.9 +/- 11.7 years; MD: -3.2 +/- 5.1 dB) and 16 healthy White individuals (age: 33.2 +/- 6.4 years; MD: -0.8 +/- 0.8 dB) were included in the study. Participants underwent Rarebit perimetry testing (central field, software version 4) and an OCT fast retinal nerve fibre layer (RNFL) scan. Correlation was investigated between hemifield Rarebit scores and the corresponding RNFL values, as well as between global Rarebit scores and the respective RNFL measures. Statistically significant correlations of average hit rate (HR) < 90 and mean hit rate (MHR) were detected with Max-Min and average thickness (Pearson's r ranging from 0.393 to 0.474). Number HR < 90 showed a moderate correlation only with Max-Min (r = -0.396, P = 0.030). Regarding the association between hemifield hit rates and the corresponding OCT thickness parameters, only inferior maximum correlated moderately with HR superior (r = 0.385, P = 0.035). A tendency was detected for the relationship of superior maximum with HR inferior (r = 0.345, P = 0.062). For the control group, no significant correlation was found for any of the global or hemifield indices and the corresponding thickness values. Although Rarebit perimetry is based on a physiological principle distinctly different from conventional perimetry, it provides global indicators of neuroretinal matrix integrity that correlate with some OCT-derived RNFL thickness measures.

This issue of Acta

This issue of Acta celebrates the centennial anniversary of the Swedish Ophthalmological Society and the great contributions of Swedish ophthalmologists and eye researchers to our field of science. The cover illustration shows the centennial jubilee medal of the Swedish Ophthalmological Society with Allvar Gullstrand, the only ophthalmologist ever to receive the Nobel price. The editorial is written by Stefan Seregard, where he looks at Swedish ophthalmology in the present and future. Berndt Ehinger reviews the highlights of Swedish ophthalmology in the twentieth century in a historical article. Ahti Tarkkanen received the 2008 Acta Ophthalmologica honorary award and gold medal and gave an honorary lecture at the Nordic Ophthalmological meeting in Tromsö last summer. He contributes a review article on exfoliation syndrome and concludes that exfoliation syndrome is not related to increase mortality for cardiovascular disease and that complete internal medical examination is not needed in symptom-free patients with exfoliation syndrome in the eye. Bartling et al. in Stockholm describe an algorithm that accurately evaluates optic disc parameters on digital fundus photographs. Spitzer et al. in Germany created a slow release dexamethasone gel and suggest this may be a useful postoperative treatment following glaucoma filtration surgery. Hoevenaars et al. in Maastricht did not find a correlation between the treatment compliance and patients′ knowledge of glaucoma medication. Dietlein et al. in Cologne conclude that older patients have considerable problems in administering eye drops to themselves from single use containers. Kaluzny et al. in Poland and USA found that latanoprost and a combination of pilocarpine and timolol were equally effective in reducing intraocular pressure, but the pilocarpine timolol combination had more ocular side effects. Lee et al. in United Kingdom injected mitomycin into Tenon′s layer during trabeculectomy surgery and found this to be a useful approach. Katsanos et al. in Greece report a correlation between rarebit perimetry and retinal nerve fibre layer thickness in glaucoma as measured with ocular coherent tomography. Nielsen et al. in Copenhagen found that some groups of children with developmental delay have an increased risk of ophthalmic disorders. Feucht et al. in Hamburg found that patients with neurofibromatosis 2 have an increased risk of strabismus, refractive errors and nystagmus. Wollensak and Iomdina in Germany and Russia have discovered a method to increase scleral collagen cross-linking and biomechanical strength and suggest that this may have a role in myopia. Biró and Schvöller in Hungary studied visual sensations of patients undergoing cataract surgery and suggest that patients should be informed of this phenomenon. Wakabayashi et al. in Osaka examined fundus autofluorescence in patients with macular holes and found this to reflect anatomic and functional changes in the retina. Hirose et al. in Japan found that systemic corticoid therapy improved blood flow in patients with VKH disease. Wang et al. in Taiwan found that suprachoroidal haemorrhage may occur following intraocular surgery and age-related macular degeneration. Visual acuity and retinal detachment are important prognostic factors in this disorder. Zibrandtsen et al. in Denmark used optical coherence tomography to demonstrate photoreceptor atrophy in acute zonal occult outer retinopathy. Ostri et al. in Copenhagen describe a case of Wegener′s granulomatosis in the orbit. Ikewaki et al. in Japan describe a case of peribulbar fungal abscess and endophthalmitis following subtenon injection of triamcinolone. Birgitta Haargaard interviews Professor Michael Larsen. We also publish a list of some of the most interesting conferences in 2009. This issue of Acta provides a lot of reading material for those interested in glaucoma and exfoliation, with a maintenance dose for those interested in other fields of ophthalmology. Acta celebrates the 100 year history of the Swedish Ophthalmological Society. I wish all readers of Acta a Merry Christmas and a Happy New Year.

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Purpose of the study was to compare Rarebit Perimetry (RP) with Standard Automatic Perimetry (SAP) in patients with ischemic retrochiasmal lesions. Seventeen patients with homonymous hemianopia underwent SAP and RP. Correlation between the two techniques was evaluated, congruent defects were quantified in the spared hemifield and residual vision areas were investigated in the blind hemifield. A strong correlation was found between SAP and RP. In the spared hemifield, RP detected congruent defects in a higher percentage of cases. Residual detection function has been found at RP in 69,2 % of perimetrically blind visual field quadrants as assessed by SAP. In conclusion, RP appears to be useful to assess visual function in hemianopic patients. As compared to SAP, it seems able to detect small congruent defects in a higher percentage of cases. Finally, a certain residual function seems to be present at RP in the blind regions of the visual field, however, for this finding further demonstrations are required.

A screening test for visual disorders based on Rarebit perimetry

Abstract Purpose To evaluate the clinical usefulness of a newly developed screening program, the VisuBit™ Quick test, based on the Rarebit perimetric technique (Frisén 2002). Methods Twenty‐one subjects (32 eyes), 6 males and 15 females, median age 47 years (27‐67), were examined using the VisuBit Quick and Full test, both including the Fovea test (4x3°visual field) and the Field test (30x20° visual field). Two subjects had amblyopia in one eye, one of these had normal visual acuity in the other eye and one had a history of central serous retinopathy in one eye, 2 subjects had a history of optic neuritis in both eyes and 2 had glaucoma in both eyes. All other eyes were healthy and had normal visual acuity. Results The correlation coefficients between number of unperceived stimuli in the Quick and the Full test were 0.95 in the Fovea and in the 0.86 Field test. In the Quick Field test more than 4 unperceived stimuli predicted a subnormal result (MHR &lt; 90%; Martin &amp; Wanger 2004) in the Full Test. In the Fovea Test more than 2 unperceived stimuli predicted a subnormal results (MHR &lt; 97%; Nilsson et al 2007). The positive and negative predictive values for the Quick Fovea test were 0.95 and 0.77, respectively. Corresponding values for the Quick Field test were 0.95 and 0.85. Conclusion The findings in this pilotstudy indicate that this implementation of the Rarebit perimetric technique may be useful for rapid screening for visual disorders.