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To evaluate the impact of dry eye on reading performance.Out-loud and silent reading in patients with clinically significant dry eye (n=41) and controls (n=50) was evaluated using standardised texts. Dry eye measures included tear film break-up time, Schirmer's test and corneal epithelial staining. Symptoms were assessed by the Ocular Surface Disease Index (OSDI).The dry eye group had a greater proportion of women as compared with the control group but did not differ in age, race, education level or visual acuity (p≥0.05 for all). Out-loud reading speed averaged 148 words per minute (wpm) in dry eye subjects and 163 wpm in controls (p=0.006). Prolonged silent reading speed averaged 199 wpm in dry eye subjects versus 226 wpm in controls (p=0.03). In multivariable regression models, out-loud and sustained silent reading speeds were 10 wpm (95% CI -20 to -1 wpm, p=0.039) and 14% (95% CI -25% to -2%, p=0.032) slower, respectively, in dry eye subjects as compared with controls. Greater corneal staining was associated with slower out-loud (-2 wpm/1 unit increase in staining score, 95% CI =-3 to -0.3 wpm) and silent (-2%, 95% CI -4 to -0.6 wpm) reading speeds (p0.02 for both). Significant interactions were found between OSDI score and word-specific features (longer and less commonly used words) on out-loud reading speed (p0.05 for both).Dry eye is associated with slower out-loud and silent reading speeds, providing direct evidence regarding the functional impact of dry eye. Reading speed represents a measurable clinical finding that correlates directly with dry eye severity.

Aims To determine the influence of single-vision lenses (SVLs) and progressive addition lenses (PALs) on the near vision posture of myopic children based on their near phoria. Methods Sixty-two myopic children were assigned to wear SVLs followed by PALs. Eighteen children were esophoric (greater than +1), 18 were orthophoric (−1 to 1) and 26 were exophoric (less than −1) at near. Reading distance, head tilt and ocular gaze angles were measured using an electromagnetic system after adaptation to each lens type. Results The lens type did not influence reading distance or head tilt angle (p>0.05 for both), but ocular gaze angle decreased significantly with the PALs (F=9.25, p=0.004). With the PALs, exophoric children exhibited significantly increased head tilt angle (p=0.003) and reduced ocular gaze angle (p=0.004) compared with esophoric children. Near non-exophoric children exhibited similar eye and head postures when wearing SVLs and PALs, whereas exophoric children exhibited reduced ocular gaze angle (t=−3.18, p=0.04) with PALs compared with SVLs. Using PALs for reading, the mean addition power employed by esophoric children was significantly greater than exophoric children (p=0.04). Conclusions The lens type and the near phoria state affected near vision posture. During reading, myopic esophoric children used a lower portion of their PALs compared with exophoric children, resulting in greater addition power. These results may partially explain why myopic children with near esophoria exhibited superior treatment effects in myopia control trials using PALs.

To compare cycloplegic autorefraction with non-cycloplegic subjective refraction across all age and refractive error groups.In a cross-sectional study with random stratified cluster sampling, 160 clusters were chosen from various districts proportionate to the population of each district in Tehran. Following retinoscopy and autorefraction with the 0.25 D bracketing (Topcon KR-8000, Topcon, Tokyo, Japan), all participants had a subjective refraction. Then all participants underwent cycloplegic autorefraction.The final analysis was performed on 3482 participants with a mean age of 31.7 years (range 5-92 years). Based on cycloplegic and subjective refraction, mean spherical equivalent (SE) was +0.31±1.80 and -0.32±1.61 D, respectively (p0.001). The 95% limits of agreement (LoA) between these two types of refraction were from -0.40 to 1.70 D. The largest difference between these two types of refraction was seen in the age group of 5-10 years (1.11±0.60 D), and the smallest difference was in the age group of70 years (0.34±0.45 D). The 95% LoA was -0.52 to 0.89 D in patients with myopia and -0.12 to 2.04 D in patients with hyperopia. We found that female gender (coefficients=0.048), older age (coefficients=-0.247), higher education (coefficients=-0.043) and cycloplegic SE (coefficients=-0.472) significantly correlated with lower intermethod differences.The cycloplegic refraction is more sensitive than the subjective one to measure refractive error at all age groups especially in children and young adults. The cyclorefraction technique is highly recommended to exactly measure the refractive error in momentous conditions such as refractive surgery, epidemiological researches and amblyopia therapy, especially in hypermetropic eyes and paediatric cases.

Background/Aims There is an increasing recognition that visuocognitive difficulties occur in children with neurodevelopmental problems. We obtained normative data for the performance of primary school children using three tests of visuocognitive function that are practicable in a clinical setting. Methods We tested 214 children aged between 4 and 11 years without known developmental problems, using tests to assess (1) orientation recognition and adaptive movement (postbox task), (2) object recognition (rectangles task) and (3) spatial integration (contours task). Results 96% could do the postbox task with ease—only 4% (all aged 99% of children aged ≥6 years had no, or minor, difficulties. Median scores for the contours task improved with age, and after age 8 years, 99% could see the contour using long-range spatial integration rather than density. Conclusions These different aspects of children’s visuocognitive performance were testable in a field setting. The data provide a benchmark by which to judge performance of children with neurodevelopmental problems and may be useful in assessment with a view to providing effective supportive strategies for children whose visuocognitive skills are lower than the expectation for their age.

Aim: To examine the relationship between the two UK vision standards for driving: the ability to read a number-plate at 20 m and achieving 6/12 (+0.30 logMAR). \ud \ud \ud Methods: 120 participants were assessed without refractive correction in this cross-sectional study. Vision was assessed with a Snellen chart, Early Treatment of Diabetic Retinopathy Study (ETDRS) style logMAR letter chart and logMAR chart using Landolt rings. Ability to read a post-2001 number-plate was assessed outdoors. \ud \ud \ud Results: For all charts, there was an ‘overlap zone’ of visions within which it was uncertain whether participants would pass the number-plate test. Within this zone, sensitivity and specificity of the 6/12 cut-off for predicting number-plate performance were reasonable for Snellen and ETDRS style charts, but poor for Landolt. All participants with 6/7.5 Snellen (+0.10 logMAR ETDRS) or better could read a number-plate. Some participants (2–6%) with vision between this level and 6/12 could not read a number-plate, and 14%–15% could read a number-plate but not achieve 6/12. \ud \ud \ud Conclusions: To best predict drivers’ ability to read a number-plate, vision should be assessed using a logMAR letter chart or a Snellen chart scored by full line. Drivers with 6/7.5 (+0.10 logMAR) or better vision can be advised that they meet the driving standard. Drivers with acuity between 6/9 and 6/12 (+0.12—+0.30 logMAR) should be advised to check their ability to read a number-plate, as some may not be able to. Clinicians will see patients who can read a number-plate, but do not achieve 6/12, who will need improved vision to meet visual requirements for driving.

Purpose To examine the relationship between visual acuity (VA) and self-reported vision (SRV) in relation to falls in 8317 participants of the European Prospective Investigation into Cancer-Norfolk Eye study. Methods All participants completed a health questionnaire that included a question regarding SRV and questions regarding the number of falls in the past year. Distance VA was measured using a logMAR chart for each eye. Poor SRV was defined as those reporting fair or poor distance vision. The relationship between VA and SRV and self-rated falls was analysed by logistic regression, adjusting for age, sex, physical activity, body mass index, chronic disease, medication use and grip strength. Results Of 8317 participants, 26.7% (95% CI 25.7% to 27.7%) had fallen in the past 12 months. Worse VA and poorer SRV were associated with one or more falls in multivariable analysis (OR for falls=1.31, 95% CI 1.04 to 1.66 and OR=1.32, 95% CI 1.09 to 1.61, respectively). Poorer SRV was significantly associated with falls even after adjusting for VA (OR=1.28, 95% CI 1.05 to 1.57). Conclusions SRV was associated with falls independently of VA and could be used as a simple proxy measure for other aspects of visual function to detect people requiring vision-related falls interventions.

We examined whether retinitis pigmentosa (RP) subjects' worse-than-usual vision measures were related to episodic changes in psychosocial factors and/or general health.In a prospective, cohort study, 37 RP subjects self-administered personal computer (PC)-based visual acuity (VA), contrast sensitivity (CS) and visual field (VF) tests at home twice a week, for 16 sessions in 2-3 months. Subjects rated their general health prior to each vision test session, and completed the Perceived Stress Scale, Positive and Negative Affect Schedules, and Epworth and Stanford Sleepiness Scales immediately after each session.Nine subjects with reduced mean VA0.5 log minimal angle of resolution (logMAR) on average had statistically significant 26% more sessions with measured deviations ≥0.1 logMAR from their mean (95% CI 20% to 32%; p0.001), which were not significantly related to changes in psychosocial factors or general health. Measured deviations ≥0.1 logCS from mean CS were not statistically significantly related to any measured factors. We found a statistically significant increased frequency of sessions with ≥20% VF reduction from the mean (p0.001) as mean log VF area was reduced. Subjects reporting reduced general health during a session had a statistically significant over twofold greater odds of having a VF reduction from the mean beyond 1 SD (95% CI 1.26 to 5.00; p=0.009).Measured episodic VF reductions were more common in advanced RP and related to decreased general health at a session, which should be considered during clinical examinations and trials when determining true changes in vision. We did not find evidence that fluctuations in psychosocial factors were significantly correlated with vision reductions across subjects.

Background/aims To investigate the influence of a period of sustained near work upon axial length in groups of emmetropes (EMM) and myopes. Methods Forty young adult subjects (20 myopes and 20 emmetropes) were recruited for the study. Myopes were further classified as early onset (EOM), late onset (LOM), stable (SM) or progressing (PM) subgroups. Axial length was measured with the IOLMaster instrument before, immediately after and then again 10 min after a continuous 30 min near task of 5 D accommodation demand. Measures of distance objective refraction were also collected. Results Significant changes in axial length were observed immediately following the near task. EOM axial length elongated on average by 0.027±0.021 mm, LOM by 0.014±0.020 mm, EMM by 0.010±0.015 mm, PM by 0.031±0.022 mm and SM by 0.014±0.018 mm. At the conclusion of the 10 min regression period, axial length measures were not significantly different from baseline values. Conclusion Axial elongation was observed following a prolonged near task. Both EOM and PM groups showed increases in axial length that were significantly greater than emmetropes.

Objectives: Following a 3.7-fold increase in the rate of cataract surgery in the UK between 1989 and 2004, concern has been raised as to whether this has been accompanied by an excessive decline in the threshold such that some operations are inappropriate. The objective was to measure the impact of surgery on a representative sample of patients so as to determine whether or not overutilisation of surgery is occurring.\ud \ud Design: Prospective cohort assessed before and 3 months after surgery.\ud \ud Setting: Ten providers (four NHS hospitals, three NHS treatment centres, three independent sector treatment centres) from across England.\ud \ud Participants: 861 patients undergoing first eye (569) or second eye (292) cataract surgery provided preoperative data of whom 745 (87%) completed postoperative questionnaires.\ud \ud Main outcome measures: Patient-reported visual function (VF-14); general health status and quality of life (EQ5D); postoperative complications; overall view of the operation and its impact.\ud \ud Results: Overall, visual function improved (mean VF-14 score increased from 83.2 (SD 17.3) to 93.7 (SD 13.2)). Self-reported general health status deteriorated (20.3% fair or poor before surgery compared with 25% afterwards) which was reflected in the mean EQ5D score (0.82 vs 0.79; p = 0.003). At least one complication was reported by 66 (8.9%) patients, though this probably overestimated the true incidence. If the appropriateness of surgery is based on an increase in VF-14 score of 5.5 (that corresponds to patients’ reporting being "a little better"), 30% of operations would be deemed inappropriate. If an increase of 12.2 (patients’ reports of being "much better") is adopted, the proportion inappropriate is 49%. Using a different approach to determining a minimally important difference, the proportion inappropriate would be closer to 20%. Although visual function (VF-14) scores were unchanged or deteriorated in 25% of patients, 93.1% rated the results of the operation as "good," "very good" or "excellent," and 93.5% felt their eye problem was "better." This partly reflects inadequacies in the validity of the VF-14.\ud \ud Conclusions: Improvement in the provision of cataract surgery has been accompanied by a reduction in the visual function threshold. However, methodological difficulties in measuring the impact of cataract surgery on visual function and quality of life mean it is impossible to determine whether or not overutilisation of cataract surgery is occurring.\ud \ud N Black1, J Browne1, J van der Meulen1, L Jamieson2, L Copley2 and J Lewsey3

Background/Aim: The COMPlog clinical visual acuity measuring system is being developed for both routine and research use. This study aimed to validate its performance in amblyopic children and both normal and diseased adults against the gold standard ETDRS chart and the E-ETDRS computerised acuity measurement algorithm. Method: Timed test and retest fully interpolated five letters per line logMAR visual acuity measurements were taken for 70 adults and 59 amblyopic children using the ETDRS chart and the COMPlog visual acuity measurement system. 39 of the adults also underwent computerised acuity testing using the E-ETDRS testing algorithm. The tested adults included normals as well as subjects with a range of ocular diseases. The methods of Bland and Altman were employed with test–retest variability (TRV) expressed as 95% confidence limits for agreement. Results: No significant bias was observed between the gold standard ETDRS acuity measurements and those taken with either COMPlog or E-ETDRS. TRVs of ±0.12 logMAR and ±0.10 logMAR were respectively found for COMPlog measurements in the amblyopic children and adult groups compared with ±0.12 logMAR for the ETDRS chart in both groups. The TRV of the E-ETDRS system was slightly greater at ±0.16 logMAR. Median testing times for COMPlog and ETDRS were 95 and 85 s and 66 and 56 s respectively in the paediatric and adult groups and 120 s for the E-ETDRS measurements on adults. Discussion: COMPlog measurements agree well with and are similarly reliable to the gold standard ETDRS chart with comparable test times. E-ETDRS algorithm measurements took approximately twice as long.

Purpose: A recently devised 3D computer-automated threshold Amsler grid test was used to identify early and distinctive defects in people with suspected glaucoma. Further, the location, shape and depth of these field defects were characterised. Finally, the visual fields were compared with those obtained by standard automated perimetry. Patients and methods: Glaucoma suspects were defined as those having elevated intraocular pressure (>21 mm Hg) or cup-to-disc ratio of >0.5. 33 patients and 66 eyes with risk factors for glaucoma were examined. 15 patients and 23 eyes with no risk factors were tested as controls. The recently developed 3D computer-automated threshold Amsler grid test was used. The test exhibits a grid on a computer screen at a preselected greyscale and angular resolution, and allows patients to trace those areas on the grid that are missing in their visual field using a touch screen. The 5-minute test required that the patients repeatedly outline scotomas on a touch screen with varied displays of contrast while maintaining their gaze on a central fixation marker. A 3D depiction of the visual field defects was then obtained that was further characterised by the location, shape and depth of the scotomas. The exam was repeated three times per eye. The results were compared to Humphrey visual field tests (ie, achromatic standard or SITA standard 30-2 or 24-2). Results: In this pilot study 79% of the eyes tested in the glaucoma-suspect group repeatedly demonstrated visual field loss with the 3D perimetry. The 3D depictions of visual field loss associated with these risk factors were all characteristic of or compatible with glaucoma. 71% of the eyes demonstrated arcuate defects or a nasal step. Constricted visual fields were shown in 29% of the eyes. No visual field changes were detected in the control group. Conclusions: The 3D computer-automated threshold Amsler grid test may demonstrate visual field abnormalities characteristic of glaucoma in glaucoma suspects with normal achromatic Humphrey visual field testing. This test may be used as a screening tool for the early detection of glaucoma.

Background: Contrast sensitivity measurement in UK clinical practice is most commonly performed with the Pelli–Robson chart. Aims: To compare the repeatability of two new contrast sensitivity charts and to measure their agreement with the Pelli–Robson charts. Method: Contrast sensitivity was measured monocularly using two versions of the Mars letter contrast sensitivity chart, two presentations on the Test Chart 2000 and two versions of the Pelli–Robson chart. Bland–Altman techniques were used to assess repeatability and agreement. Results: 53 subjects were recruited with visual acuity from 6/4 to 6/72. The coefficient of repeatability was 0.182 for the Pelli–Robson chart, 0.121 for the Mars chart and 0.238 for Test Chart 2000. Limits of agreement with the Pelli–Robson chart were −0.29 to +0.15 log units for the Mars letter contrast sensitivity chart and −0.32 to +0.78 log units for the Test Chart 2000. For patients with poor contrast sensitivity, the limits of agreement between the Test Chart 2000 and the Pelli–Robson chart improved from −0.33 to +0.15 log units. Conclusion: In a population of hospital ophthalmology patients, the coefficient of repeatability is better for the Mars chart and worse for the Test Chart 2000 when compared with the Pelli–Robson chart. The electronic test chart does not agree well with the Pelli–Robson chart, although this might simply be due to the performance of liquid crystal display screens at low contrast levels. The Mars letter contrast sensitivity chart shows good validity and reasonable agreement with the Pelli–Robson chart.

Background: Pharmacological treatment has been successful in some forms of acquired neurological nystagmus. However, drugs are not known to be effective in idiopathic infantile nystagmus or nystagmus associated with ocular diseases. Methods: The authors retrospectively analysed Snellen visual acuity (VA), subjective visual function, and eye movement recordings of 23 patients with nystagmus (13 secondary to multiple sclerosis, three associated with other neurological diseases, two idiopathic infantile, and five with associated ocular diseases) treated with gabapentin or memantine. Results: With gabapentin, 10 of 13 patients with nystagmus secondary to multiple sclerosis (MS) showed some improvement. Memantine improved the VA in all three patients with MS who did not improve on gabapentin. There was no change of nystagmus in other neurological disorders. Patients with congenital nystagmus showed reduction of nystagmus and their VA changes depended on the ocular pathology. Conclusion: Gabapentin and memantine may be effective in acquired nystagmus secondary to MS. To the authors’ knowledge this is the first series of patients showing that gabapentin is effective in improving nystagmus in congenital nystagmus/nystagmus associated with ocular pathology. Memantine may be useful as an alternative drug in treating patients with nystagmus.

To examine how stereoacuity changes with age as measured by a variety of stereotests.Stereoacuity has been measured in 60 normal subjects aged 17-83 years by a single observer using TNO, Titmus, Frisby near, and Frisby-Davis distance stereotests. Motor fusion was measured at (1/3) metre and 6 metres.Overall stereoacuity measured by all tests showed a mild decline with age (p0.001 for all tests; Spearman rank correlation). A marked reduction to screening or absent levels of stereoacuity was seen in five subjects aged over 55, but only with the TNO stereotest. All these subjects were able to achieve a stereoacuity of 200 seconds of arc or better with the Titmus test and 340 seconds of arc or better using the Frisby near stereotest. There was a small decline with age in the base out motor fusion range measured at 6 metres (p0.05; Spearman rank correlation). No subject described difficulty in judging distances for everyday tasks.Although subjects showed some decline in stereoacuity with age by all tests, the large drop in stereoacuity seen in some older subjects using the TNO test was probably due to difficulty overcoming the dissociative effect of the test rather than a true reduction in cortical disparity detection. Results of random dot stereotests should be interpreted with caution in older patients, particularly with respect to their ability to perform everyday visual tasks.

Aims: To determine whether the computerised version of the new aniseikonia test (NAT) is a valid, reliable method to measure aniseikonia and establish whether aniseikonia occurs in patients with epiretinal membranes (ERM) with preserved good visual acuity. Methods: With a computerised version of the NAT, horizontal and vertical aniseikonia was measured in 16 individuals (mean 47 (SD 16.46) years) with no ocular history and 14 patients (mean 67.7 (14.36) years) with ERM. Test validity was evaluated by inducing aniseikonia with size lenses. Test reliability was assessed by the test-retest method. Results: In normal individuals, the mean percentage (SD) aniseikonia was −0.24% (0.71) horizontal and 0% (0.59) vertical. Validity studies revealed mean (SD) 0.990 (0.005) horizontal and 0.991 (0.004) vertical correlation coefficients, 0.985 (0.111) horizontal and 0.989 (0.102) vertical slope. Repeatability coefficients were 1.04 horizontal and 0.88 vertical. Aniseikonia in patients with ERM ranged from 4% to 14%. Eight patients showed 2% or more size difference between horizontal and vertical meridians. Conclusions: The aniseikonia test used in this study can be considered a simple, fast, valid and reliable method to measure the difference in image size perceived by each eye. Aniseikonia does occur in symptomatic patients with ERM. The effect of ERM on image size is heterogeneous across the retinal area affected.

Aim: To report on a new model of preschool vision screening that was performed in metropolitan Seoul and to investigate the distribution of various ocular disorders in this metropolitan preschool population. Methods: Vision screening was conducted on 36 973 kindergarten children aged 3–5 years in a stepwise manner. The first step was home screening using a set of five picture cards and a questionnaire. The children who did not pass the first step (VA Results: Of those screened, 7116 (19.2%) children did not pass the home screening tests and 2058 (28.9%) out of the 7116 were referred. The results of the ophthalmological examination in eye clinics were only available for 894 children (43.4%) of those who were referred. The rest of the children did not visit ophthalmologists because they had been checked at an eye clinic, were currently under treatment, or for personal reasons. Refractive errors were found in 608 (1.6%) children. Astigmatism was associated in 78.2% of ametropes. Amblyopia was discovered in 149 (0.4%) children and refractive error was the major aetiology with a predominant rate (82.5%). Manifest strabismus was detected in 52 children. The positive predictive value of vision screening for any ophthalmological disorder was 0.77, and 0.49 for significant disorders requiring treatment. Conclusions: This preschool vision screening model was highly accessible to the children and their parents, easy to administer, and effective to detect a variety of ocular disorders. However, the participation rate of the referred children in the examinations by ophthalmologists was quite low. The performance and efficiency of this screening programme need to be optimised with further revision.

Few studies have investigated normal response characteristics of torsional optokinetic nystagmus (tOKN). The authors have investigated the effect of stimulus velocity and central/peripheral stimulation on tOKN.Torsional OKN was elicited using a sinusoidal grating rotating at velocities of 3 degrees /s to 1000 degrees /s in clockwise and anticlockwise directions. To investigate the effect of central stimulation, stimulus size was varied from 2.86 degrees to 50.8 degrees. An artificial scotoma placed over a 50.8 degrees stimulus was varied from 2.86 degrees to 43.2 degrees to investigate peripheral stimulation. Eight subjects participated in each experiment and torsional eye movements were recorded using video-oculography. The mean slow phase velocity (MSPV) and gain were calculated.The maximum gain occurred in response to 8 degrees /s stimulation. The MSPV increased up to a stimulus velocity of 200 degrees /s achieving a maximum of 3 degrees /s in both directions. MSPV was linearly correlated with the log of stimulus velocity. The smallest field size, rotating at 40 degrees /s, evoked 10% of the gain elicited by the largest display. When the most peripheral stimulus was used, the gain was maintained at 50% of the gain evoked when the full display was used.A wide range of stimulus velocities can elicit tOKN and peripheral field stimulation contributes significantly to its response.

To compare the performance of keratoconus, penetrating keratoplasty (PK), and control subjects on clinical tests of contrast and glare vision, to determine whether differences in vision were independent of visual acuity (VA), and thereby establish which vision tests are the most useful for outcome studies of PK for keratoconus.All PK subjects had keratoconus before grafting and no subjects had any other eye disease. The keratoconus (n = 11, age 35.0 (SD 11.1) years), forme fruste keratoconus (n = 6, 33.0 (13.0)), PK (n = 21, 41.2 (7.9)), and control (n = 24, 33.7 (8.6)) groups were similar in age. Vision testing, conducted with optimal refractive correction in place, included low contrast visual acuity (LCVA) and Pelli-Robson contrast sensitivity (PRCS) both with and without glare, as well as VA.Normal subjects saw better than PK subjects who in turn saw better than keratoconus subjects on all raw measures. However, when adjusted for VA, the normal group only saw significantly better than the keratoconus group on LCVA (low contrast loss 0.05 (0.04) v 0.15 (0.12), F(2,48) = 6.16; p0.01, post hoc Sheffé p0.05), and the decrements to glare were no worse than for normals. The forme fruste keratoconus group were indistinguishable from normals on all measures.PK subjects have superior vision to keratoconus subjects, but not as good as normal subjects. Including mild keratoconus subjects within a keratoconus group could confound these differences in vision. While VA is an excellent test for comparing normal, keratoconus and PK groups, additional information can be provided by LCVA and PRCS, but not by glare testing. Outcomes research into keratoconus management should include a measure in the contrast domain.

Aim: To analyse the test characteristics of orthoptic screening for amblyopia or amblyogenic risk factors (target conditions) in kindergarten. Methods: 1180 three year old children were screened by orthoptists in 121 German kindergartens. Orthoptic screening consisted of cover tests, examination of eye motility and head posture, and monocular visual acuity testing with the Lea single optotype test. Children were re-examined in kindergarten by different orthoptists after 3–6 months using a more demanding pass threshold for visual acuity. All children with at least one positive orthoptic test result or an inconclusive re-examination were referred to an ophthalmologist for diagnosis. The gold standard was set positive if a target condition was diagnosed on ophthalmological examination. It was set negative if no target condition was found upon ophthalmological examination, or if a child who screened negative or inconclusive passed the orthoptic re-examination without any positive test result. Results: The gold standard was ascertained in 1114 children. 26 (2.3%) children had a “positive” gold standard. In 10.8% of the children the initial screening was “inconclusive,” mostly due to lack of collaboration. Screening test sensitivity (based on conclusive results only) was 90.9% and specificity was 93.8%. Conclusions: Orthoptic vision screening of 3 year olds in kindergarten is sensitive and specific. However, owing to a substantial proportion of inconclusive screening results, rescreening of non-cooperative 3 year old children should be considered.

Aims: To evaluate the effect of a visual field test educational video on the reliability of the first automated visual field test of new patients. Methods: A prospective, randomised, controlled trial of an educational video on visual field test reliability of patients referred to the hospital eye service for suspected glaucoma was undertaken. Patients were randomised to either watch an educational video or a control group with no video. The video group was shown a 4.5 minute audiovisual presentation to familiarise them with the various aspects of visual field examination with particular emphasis on sources of unreliability. Reliability was determined using standard criteria of fixation loss rate less than 20%, false positive responses less than 33%, and false negative responses less than 33%. Results: 244 patients were recruited; 112 in the video group and 132 in the control group with no significant between group difference in age, sex, and density of field defects. A significant improvement in reliability (p=0.015) was observed in the group exposed to the video with 85 (75.9%) patients having reliable results compared to 81 (61.4%) in the control group. The difference was not significant for the right (first tested) eye with 93 (83.0%) of the visual fields reliable in the video group compared to 106 (80.0%) in the control group (p = 0.583), but was significant for the left (second tested) eye with 97 (86.6 %) of the video group reliable versus 97 (73.5%) of the control group (p = 0.011). Conclusions: The use of a brief, audiovisual patient information guide on taking the visual field test produced an improvement in patient reliability for individuals tested for the first time. In this trial the use of the video had most of its impact by reducing the number of unreliable fields from the second tested eye.

Aim: Psychophysical strategies designed for clinical visual field testing produce rapid estimates of threshold with relatively few stimulus presentations and so represent a trade-off between test quality and efficiency. The aim of this study was to determine the measurement error of a staircase algorithm similar to full threshold with standard automated perimetry (SAP) and frequency doubling perimetry (FDP) in glaucoma patients. Methods: Seven patients with early open angle glaucoma (OAG) were prospectively recruited. All were experienced in laboratory based psychophysics. Three matched test locations were examined with SAP (externally driven Humphrey field analyser) and FDP (CRT) in a single arbitrarily selected eye of each subject. Each location was tested twice with a 4-2-2 dB staircase strategy, similar to full threshold, and then with the method of constant stimuli (MOCS). Accuracy (threshold estimation error) was quantified by determination of differences between “true” threshold measurements made by MOCS and single staircase threshold estimates. Precision (repeatability) was quantified by the differences between repeated staircase threshold estimates. Results: Precision was relatively high for both tests, although higher for FDP than SAP at depressed sensitivity levels. The staircase strategy significantly underestimated threshold sensitivity for both test types, with the mean difference (95% CI) between staircase and MOCS thresholds being 4.48 dB (2.35 to 7.32) and 1.35 dB (0.56 to 1.73) for SAP and FDP respectively. Agreement levels (weighted kappa) between MOCS and staircase thresholds were found to be 0.48 for SAP and 0.85 for FDP. Although this “bias” appeared constant for FDP across all sensitivity levels, this was not the case for SAP where accuracy decreased at lower sensitivity levels. Conclusion: Estimations of threshold sensitivity made using staircase strategies common to clinical visual field test instrumentation are associated with varying degrees of measurement error according to visual field test type and sensitivity. In particular, SAP significantly overestimates the “true” level of sensitivity, particularly in damaged areas of the visual field, suggesting that clinical data of this type should be interpreted with caution.

Aims: In order to establish normal values and interocular differences of visual acuity, Lea symbols were applied to neurologically and ophthalmologically normal children. Methods: 385 children (21–93 months old) were examined, within a routine check up in an urban paediatric practice where Lea symbol acuity (LS) was measured. Of these children, 90 were re-examined in hospital comparing Lea symbol acuity (LS) and Landolt C acuity (LC). Strabismus, ametropia, and any organic eye disease were excluded. Results: In the paediatric practice, LS could be measured on both eyes in 54% of the children. In the age group above 36 and 48 months the success rate was 76% and 95%, respectively. Acuity in the paediatric practice ranged from 0.1 to 2.0 (median 1.25) in the whole group. Interocular acuity difference was one line or less in 80%. In the hospital, LS and LC could be measured on both eyes of 77% and 48% of the 90 children, respectively. Cooperation increased with age. LS in the hospital ranged from 0.32 to 2.0 (median 1.0) and LC from 0.16 to 1.25 (median 0.8). Interocular difference of LS acuity was one line or less in 90%. Conclusion: Lea symbols were found to be useful for visual acuity assessment in early childhood. Significant variability of visual acuity in this age group is caused by cooperation. When monocular measurements are possible on both eyes, however, the intraindividual interocular difference of visual acuity usually does not exceed one line.

BACKGROUND: The mass media have the potential to motivate people to participate in self appraisal of their own health status. An innovative communication package was designed to help people to examine vision at home. The impact of publishing the "do it yourself" (DIY) kit in Indian newspapers was evaluated. METHODS: A pretested bilingual vision testing kit was published in three newspapers. The kit comprised four tumbling Es corresponding to 6/12 line of Snellen's optotypes. Directions on using the kit were enclosed. 3 -7 days after publication of the kit, a telephone survey of newspaper readers was undertaken to evaluate the impact and cost effectiveness. RESULTS: 603 people were contacted over the telephone. 125 (20.73%) subscribed to the newspaper carrying the DIY insertion. 43.2% (54) noticed the insertion of which 88.89% (48) read the enclosed instructions carefully. 58.33% respondents felt sufficiently motivated to contact an ophthalmologist. Graduates had a 3.83 times higher probability of reading the communication insertion compared with others. Differences in relation to other demographic variables were not statistically significant. CONCLUSIONS: Newspapers are an excellent medium for communicating self appraisal kits for vision testing. The medium is cost effective and has significant reach in the urban agglomerates of India.

Background/aims—The advantages of logMAR acuity data over the Snellen fraction are well known, and yet existing logMAR charts have not been adopted into routine ophthalmic clinical use. As this may be due in part to the time required for a logMAR measurement, this study was performed to determine whether an abbreviated logMAR chart design could combine the advantages of existing charts with a clinically acceptable measurement time. Methods—The test-retest variability, agreement (with the gold standard), and time taken for “single letter” (interpolated) acuity measurements taken using three prototype “reduced logMAR” (RLM) charts and the Snellen chart were compared with those of the ETDRS chart which acted as the gold standard. The Snellen chart was also scored with the more familiar “line assignment” method. The subjects undergoing these measurements were drawn from a typical clinical outpatient population exhibiting a range of acuities. Results—The RLM A prototype chart achieved a test-retest variability of +/˛0.24 logMAR compared with +/˛0.18 for the ETDRS chart. Test-retest variability for the Snellen chart was +/˛0.24 logMAR using clinically prohibitive “single letter” scoring increasing to +/˛0.33 with the more usual “line assignment” method. All charts produced acuity data which agreed well with those of the ETDRS chart. “Single letter” acuity measurements using the prototype RLM charts were completed in approximately half the time of those taken using the ETDRS and Snellen charts. The duration of a Snellen “line assignment” measurement was not evaluated. Conclusion—The RLM A chart oVers an acceptable level of test-retest variability when compared with the gold standard ETDRS chart, while reducing the measurement time by half. Also, by allowing a faster, less variable acuity measurement than the Snellen chart, the RLM A chart can bring the benefits of logMAR acuity to routine clinical practice. (Br J Ophthalmol 2001;85:432‐436)

AIMS—To evaluate visual function and vision specific health status in patients undergoing penetrating keratoplasty for keratoconus. METHODS—A prospective longitudinal study measuring logMAR visual acuity, contrast sensitivity, disability glare, binocular visual field, stereoacuity, and subjective visual function (VF-14) was conducted on 18 patients with keratoconus undergoing penetrating keratoplasty (PK), including six patients who had already had PK in the fellow eye. Data were collected preoperatively and at 3, 9, and 18 months after surgery. RESULTS—Within 3 months of surgery there was significant improvement in aided visual acuity, contrast sensitivity, and stereoacuity (p4D) did not affect the VF-14 score significantly. CONCLUSIONS—There is substantial and rapid improvement in visual function and vision specific health status in keratoconic patients as a result of uncomplicated penetrating keratoplasty.

AIMS—To determine if the colour rivalry suppression is an index of the visual impairment in amblyopia and if the stereopsis and fusion evaluator (SAFE) instrument is a reliable indicator of the difference in visual input from the two eyes. METHODS—To test the accuracy of the SAFE instrument for measuring the visual input from the two eyes, colour rivalry suppression was measured in six normal subjects. A test neutral density filter (NDF) was placed before one eye to induce a temporary relative afferent defect and the subject selected the NDF before the fellow eye to neutralise the test NDF. In a non-paediatric private practice, 24 consecutive patients diagnosed with unilateral amblyopia were tested with the SAFE. Of the 24 amblyopes, 14 qualified for the study because they were able to fuse images and had no comorbid disease. The relation between depth of colour rivalry suppression, stereoacuity, and interocular difference in logMAR acuity was analysed. RESULTS—In normal subjects, the SAFE instrument reversed temporary defects of 0.3 to 1.8 log units to within 0.6 log units. In amblyopes, the NDF to reverse colour rivalry suppression was positively related to interocular difference in logMAR acuity (β=1.21, p

Aim—To analyse possible predictors of the self assessed functional outcome of a cataract extraction. Methods—The patients’ self assessed visual function was studied by use of a questionnaire, the “Catquest”, before and 6 months after surgery. All patients (n=1933, mean age 75.5 years, 66.8% women) who were undergoing cataract surgery in March 1995, in 35 diVerent departments of ophthalmology participating in the National Swedish Cataract Register, were included in the study. A routine ophthalmic examination was performed before and after surgery. The following preoperative variables were studied with regard to a possible relation to the outcome: age, sex, ocular comorbidity, best corrected preoperative vision (better eye), first or second eye surgery, other diseases with a need for long term medication, need for home help, need for subsidised travel by taxi. Results—Ocular comorbidity was strongly related to a “no benefit” outcome after surgery (p= 0.005). Second eye surgery and young age was related to a “very good benefit”outcome after surgery (p=0.0001 and p

Early detection of the onset or progression of macular disease is likely to become increasingly important as new treatment modalities are introduced. Current best practice involves issuing patients with an Amsler chart for daily or weekly observation with the instruction to attend for immediate assessment should any new distortion be perceived. However the sensitivity of Amsler charts in detecting macular disease can be less than 50%, implying that presentation may be delayed in over half of patients with advancing disease relying on the Amsler chart to detect progression. A likely explanation for this is the phenomenon of perceptual completion whereby regular objects are “filled‐in” across the scotoma. Although alternative tests have been developed and shown to have greater sensitivity, at present no straightforward, cheap, home‐based test of macular disease progression is available. The development of such a self‐diagnostic tool should be a research priority.

Aim: To examine the association of reported visual hallucinations and measured visual parameters in adult patients referred for low vision rehabilitation. Methods: All patients (N = 225) referred to a low vision rehabilitation clinic for a calendar year were asked a standardised question about symptoms of formed visual hallucinations. Best corrected visual acuity and contrast sensitivity using the Pelli-Robson chart were measured. We conducted multiple logistic regression analysis of the association between visual hallucinations and visual parameters. Results: Of the total cohort, 78 (35%) reported visual hallucinations. Visual acuity and contrast sensitivity were considered in four quartiles. In multiple logistic regression controlling for contrast sensitivity, age, gender, report of depression and independence, measured acuity in each of the poorer three categories (compared to the best) was not associated with reported hallucinations. Contrast sensitivity in the three poorer quartiles (compared to the best) was strongly associated with the report of hallucinations (OR 4.1, CI 1.1, 15.9; OR 10.5, CI 2.6, 42.1; OR 28.1, CI 5.6, 140.9) after controlling for acuity, age, sex, depression and independence. Conclusions: Lowest contrast sensitivity was the strongest predictor of reported hallucinations after adjusting for visual acuity.

Unilateral visual impairment (UVI) as a result of amblyopia or refractive error is common in childhood, but its functional significance remains largely unexplored.To investigate the influence of visual acuity and stereoacuity on the performance of preschool children on tasks requiring visuomotor skills and visuospatial ability.Children with normal (6/6) visual acuity (VA) in both eyes and children with UVI ranging from 6/9 to 6/60, with no strabismus and normal vision in the fellow eye, were assessed on a neurodevelopmental test battery of visually guided tasks.50 children (mean age (SD): 52.4 (5.7) months; median (range) VA: 6/9 (6/6 to 6/60); median (range) stereoacuity: 70 seconds arc (40-absent)) completed the test battery. UVI and stereoacuity correlated moderately (Pearson's r = 0.537, p0.001) but seven of 28 children with impaired VA had normal stereoacuity (70 seconds arc) while five of 22 with normal VA had abnormal stereoacuity. Stereoacuity correlated with performance on a task requiring fine hand-eye coordination and a task measuring visuomotor integration. UVI did not correlate with performance on any test battery items.UVI itself does not appear to relate to visuomotor actions, except when associated with reduced stereoacuity. Stereoacuity appears to have an influential role in fine visuomotor actions and spatial representation in preschool children.

AIM—To determine the visual outcome at 7-8 years in very low birth weight (VLBW: birth weight

AIMS—To estimate the prevalence of Usher syndrome in the city of Birmingham, and to establish a database of patients who have been classified into different clinical subtypes essential for future gene mutation analysis. METHODS—Symptomatic cases of Usher syndrome (US) resident in the city of Birmingham in June 1994 were ascertained through multiple sources. Ophthalmic and audiological reassessment together with examination of medical records and patient questionnaires allowed classification of three subtypes, US 1, US 2, and US 3. In addition, family pedigrees were examined and blood was taken from index patients for DNA extraction. RESULTS—In the population aged over 15 years the prevalence was 6.2 per 100 000 population for all US subtypes. The prevalence for US 1 and US 2 was 5.3 per 100 000 population. This is greater than previously reported. In the age group 30-49 years the prevalence approached 1 in 10 000. Clinical classification found 33% US 1, 47% US 2, and 20% US 3. CONCLUSION—This higher prevalence rate and greater frequency of US 2 and US 3 may reflect a more complete ascertainment.

AIMS--This study was carried out to investigate the precise pattern of visual loss associated with subfoveal choroidal neovascular membranes and the mechanism by which vision is stabilised or improved after submacular surgery. METHODS--Preoperative and postoperative quantitative microperimetry using the scanning laser ophthalmoscope was performed on six eyes of five patients with age-related macular degeneration who underwent subfoveal choroidal neovascular membrane excision. The relation of the microperimetry findings to the preoperative and postoperative fluorescein angiographic features was also assessed. RESULTS--Four of the six eyes had visual improvement by the 6 month postoperative visit; the other two had stabilisation of vision at the preoperative level. Despite these beneficial visual effects, none of the patients fixated within the bed of the excised choroidal neovascular membrane. Subfoveal choroidal membrane excision was associated with a 36% average increase in the absolute scotoma at the 1 month postoperative visit, compared with the preoperative size. The postoperative scotoma appeared to remain stable or decreased slightly in size between the 6 month and 1 year postoperative visits. Recovery of vision was associated with the development of a more stable preferred eccentric fixation locus, of which the distance from the centre of the foveal avascular zone was related to final postoperative vision. Most of the eccentric fixation loci were inferotemporal to the bed of the excised choroidal neovascular membrane. The surgical retinotomy site was associated with persistent postoperative relative scotoma in five of the six cases, but resolved in one patient after 1 year. CONCLUSION--These findings indicate that quantitative scanning laser ophthalmoscope microperimetry may aid in the surgical planning of subfoveal choroidal neovascular membrane excision.

Background/aim: The “compact reduced logMAR” (cRLM) chart is being developed as a logMAR alternative to the Snellen chart. It is closer spaced and has fewer letters per line than conventional logMAR charts. Information regarding the performance of such a chart in amblyopes and children is therefore required. This study aimed to investigate the performance of the cRLM chart in amblyopic children. Methods: Timed test and retest measurements using two versions of each chart design were obtained on the amblyopic eye of 43 children. Using the methods of Bland and Altman the agreement, test-retest variability (95% confidence limits for agreement, TRV) and test time of the cRLM and the current clinical standard Snellen chart were compared to the gold standard ETDRS logMAR chart. Results: No systematic bias between chart designs was found. For line assignment scoring the respective TRVs were 0.20 logMAR, 0.20 logMAR, and 0.30 logMAR. Single letter scoring TRVs were cRLM (95% CL 0.17) logMAR, ETDRS (95% CL 0.14) logMAR, and Snellen (95% CL 0.29) logMAR. Median testing times were ETDRS 60 seconds, cRLM 40 seconds, Snellen 30 seconds. Conclusion: The sensitivity to change of the cRLM equalled or approached that of the gold standard ETDRS and was at least 50% better than that of Snellen. This enhanced sensitivity to change was at the cost of only a 10 second time penalty compared to Snellen. The cRLM chart was approximately half the width of the ETDRS chart. The cRLM chart may represent a clinically acceptable compromise between the desire to obtain logMAR acuities of reasonable and known sensitivity to change, chart size, and testing time.

Data from all patients registered blind from diabetic retinopathy in Avon during a 16 month period were analysed with regard to management before hospital referral. The main findings were: 50% of the patients had no screening for retinopathy and were known to be diabetic; 25% were regularly screened for retinopathy (three quarters by local opticians); 22% were newly diagnosed as diabetic at the time of hospital referral. The degree of visual loss at the time of first hospital attendance was found to be marked (average 4.4 Snellen lines of acuity) but was not significantly different for different sources of referral. Only one eye of one patient had normal acuity at first attendance and 88% had lost two or more lines; 72% of registrations were a result of diabetic maculopathy. Delay from waiting for hospital appointments did not contribute significantly to the outcome in the group of patients studied.

AIM—To provide information on the use of vision tests in clinical decision making about cataract surgery in the UK. METHOD—A questionnaire survey was mailed to 703 consultant ophthalmologists. RESULTS—A response rate of 70% was obtained. Monocular distance visual acuity was the only visual function that was tested routinely by all surgeons. Supplementary use of contrast sensitivity and glare testing was low. Many surgeons (35%) were willing to consider surgery at acuity levels better than 6/9 and a small but substantial number (12%) indicated that they did not use an acuity criterion. Being prepared to consider surgery at relatively good levels of acuity was not associated with more common use of other tests of vision. CONCLUSION—Many UK surgeons are prepared to consider cataract extraction at relatively good levels of visual acuity and use other vision tests infrequently.

Two elderly women have each received a monofocal intraocular lens in one eye and a 3M diffractive bifocal intraocular lens in the other eye. Both eyes were shown to have equivalent retinal/neural function by measuring contrast sensitivity to laser interference fringes which bypassed refractive and other defects of the ocular media. The eyes with a bifocal intraocular lens displayed a much greater depth of focus, though at the expense of diminished contrast sensitivity compared with the normal values expected for that age. Simulation experiments suggested that the observed reduction in contrast sensitivity was not adequately explained by a simple reduction in retinal illumination of the in-focus image as might intuitively be expected from the bifocal separation of incident light to two simultaneous focal points. The simultaneous superimposition of the out-of-focus image on the in-focus image must also be considered, since this caused a significant reduction in contrast sensitivity when the retinal illumination was insufficiently above the photopic luminance threshold.

The visual acuity, the difference in sensitivity of the two eyes to light (brightness ratio), and contrast sensitivity were assessed in 28 patients with chronic open angle glaucoma and compared with those of 41 normal controls of similar ages and visual acuity. The results obtained were related to the results of Tübingen visual field analysis in patients with glaucoma. Twenty-four of the 28 glaucoma patients (86%) had a significant disparity in brightness ratio between the two eyes. This was found to match the frequency of visual field loss. Moreover, there was a significant relationship between the interocular differences in brightness sense and the difference in the degree of visual field loss between the two eyes. Of the glaucoma patients 39% had sum contrast sensitivities outside the normal range for age-matched normal controls. No significant correlation was found between the interocular difference in brightness sense and the visual acuity or the interocular difference in sum contrast sensitivity. It is concluded that, in the presence of a normal visual acuity, the brightness ratio test warrants evaluation as a potential screening test for chronic open angle glaucoma.

The most frequently used method for testing foveal function is a visual acuity (VA) measurement using letter charts. However, with less than two thirds of the optic nerve axons a decimal VA of 20/20 can still be achieved.1 Therefore, this test cannot be regarded as sensitive to low-degree degradation of the foveal function. Furthermore, the test targets that are used are many times larger than the retinal receptive units.2 To address this shortcoming a so-called rarebit test has been developed. In this test, microdot stimuli that match the size of the receptive units of the retina, are briefly presented, and may therefore be more sensitive to detect early damage at the level of these receptive fields.2 These tests can be applied in the central and peripheral vision. They describe the functional state of the neural matrix of the retina. Rarebit fovea testing has diagnostic potential in conditions like age related macular degeneration (AMD). A …

Relationship between structure and function with regard to glaucoma The study by Kanadani et al 1 to elucidate the relationship between structure and function, especially with regard to glaucoma, is timely. Their paper is particularly interesting in that it provides information on not one but two measures of function: the visual field and the multifocal visual evoked potential technique. The investigators report that macular thicknesses (measured by optical computerized tomography) were in agreement with the 10-2 Humphrey visual field and multifocal visual evoked potential technique to the same degree as the two functional tests. Local agreement was present as well; inferior and superior sectors showed abnormal macular thickness in 78% and 65% of the points. These results, obtained at the macula, give a message similar to that of other structural measures such as peripapillary nerve fibre layer thickness and morphometry of the optic nerve head. The message seems to be that though there is good overall agreement between structure and function, it is not sufficient to yield a test that provides an unequivocal measure of damage in a given patient. Gone are the days when we hoped that a unique quantitative objective measure would be found and would replace subjective tests prone to noise and artefacts and demanding expert interpretation. Does this means that we should give up on our effort to perform quantitative and objective tests in glaucoma? I opine that the answer is “no”, but clearly we are forced to delve more deeply into the subject and accept the fact that valuable information will be gleaned …

What are the effects of uniocular disorders on visual outcome? Are some treatment strategies more effective than others? Has the good eye been compromised? Does the age of onset matter? What is the influence of deprivation versus abnormal competition between an affected eye and a fellow good eye? These are all important questions. In answering these questions, we often turn primarily to the “gold standard”—Snellen acuity. But good vision involves more than being able to decipher small details at high contrast. It also involves sensitivity to objects of low contrast, stereopsis, being able to accurately align easily visible objects, the perception of motion, and a host of other aspects of vision. Studies of animals indicate that some aspects of vision are more susceptible to abnormal visual input than others and that the sensitive period differs for different aspects of vision.1 Thus, a clear understanding of visual outcome requires the assessment of more than just visual acuity. …

This article looks at outcome measures for the glaucomas and makes suggestions on how they may be used to guide long term management. Glaucoma is the term given to diseases of the optic nerve head which exhibit a characteristic deformity of the optic disc (glaucomatous cupping) with loss of retinal neurons together with commensurate visual loss. The intraocular pressure (IOP) may be above the upper limit of normal. The relation between elevated IOP and glaucomatous cupping is worryingly uncertain. Total population studies suggest an increasing incidence with increasing IOP, but the rise for each unit of IOP increase only becomes dramatic above 30 mm Hg.1Additionally, a significant proportion of patients with chronic glaucoma will have an IOP within the normal range.1 2 The susceptibility of an eye to a particular IOP level clearly varies, patient A being more susceptible to a particular IOP …

Patients with various macular and optic nerve abnormalities underwent Snellen acuity, transient VER acuity, and Arden grating testing. Snellen acuity was the coarsest of the 3 evaluations, generally falling after Arden scores and VER acuity had already undergone significant degradation. The Arden gratings appeared to be the most sensitive of the 3 tests, equalling VER performance in optic nerve diseases and surpassing it in macular diseases. Variations in results between the different tests are generally understandable if one considers the functions tested by each and the anatomical derangements caused by the diseases in question. The Arden grating test appears to be an excellent and sensitive screening test for central visual disturbances.

(1) Chronic glaucoma accounts for a high proportion of blindness which is preventable and calls for energetic action because existing knowledge is not applied as it should be because of the indifference of the Department of Health and Social Security to the glaucoma problem. (2) The condition is frequently insidious and advanced before being identified, and requires life-long supervision. (3) When diagnosed, the management of glaucoma is frequently inadequate and intermittent for a variety of reasons. (4) AtKing's College Hospital, a Glaucoma Centre has been initiated to supervise accurately and regularly a large number of glaucoma patients, assisted by numerical recording and computer analysis. While we are fortunate in having a computer in the hospital, it is important to emphasize that the system can be operated without this facility, either by employing manual methods, or by batch processing. It would be both possible and desirable to organize recording a nd analysis on a regional basis in collaboration with hospitals wishing to participiate. (5) Attempts are being made to improve the early diagnosis ofglaucoma by better communication between the hospital ophthalmologists, and other members of the medical, optical, and ancillary professions by lectures, demonstrations, and publications. (6) Research is always hampered by the absence of factual knowledge. It is planned to use fully the opportunity for research into glaucoma made possible by this basic organization. At present however, we consider it more important to carry out investigations into the problems of organizing the investigation, treatment, and follow-up of glaucoma patients than t o embark on a few individual projects of research. We are serously hampered in our work by shortage of funds for staff and facilities, but we look forward confidently to the time when, with the essential support of the Department of Health, these methods will give us access to the facts of glaucoma, which besides enabling us to give a high standard of treatment to our patients, will give us an unprecedented opportunity of wide ranging research into all aspects of this important disorder.

A procedure specifically adapted for children of preschool age has been used to measure contrast sensitivity in emmetropic children aged 3 to 5 years. Mothers of the children acted as adult observers using the same procedure. The results show that the contrast sensitivity function of adults and children is very similar, sensitivity for the children being slightly lower than that for adults at all spatial frequencies. The sensory and cognitive factors involved in these differences are discussed.

A simple technique is described for assessing the sensitivity of the human visual system to gratings at threshold contrast. The technique has advantages for clinical use in that it is (1) inexpensive, (2) quick to administer, (3) portable, and (4) relatively free from bias. Forty-two diabetic patients and 84 normal controls have been tested. Fifteen diabetic patients (6/20 with retinopathy and 9/22 without) had test scores more than two standard deviations below the norm for age-matched controls.

Adult emmetropes and myopes were tested with the Catford drum and the results compared with subjective (Landolt C) acuity. For he emmetropes the Catford drum was found to overestimate visual acuity by a factor of approximately 4. For myopes, and emmetropes viewing through plus lenses, the discrepancies were much larger. Since the Catford drum not only overestimates acuity but will do so by a factor which varies for different visual disorders, caution is needed in clinical interpretation of results obtained with it.