The visual analogue scale for the measurement of pain is not linear.
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Humans↗
Biomedical subjects
K Pesudovs
Publications and source records attributed to K Pesudovs.
Comparison of autologous serum eye drops with conventional therapy in a randomised controlled crossover trial for ocular surface disease.
AIMS: To evaluate the efficacy of 50% autologous serum drops against conventional treatment in ocular surface disorders refractory to normal treatments in a prospective randomised crossover trial. METHOD: Patients fulfilling ophthalmological and haematological entry criteria were randomised to either 3 months of autologous serum 50% followed by 3 months of their conventional treatment, or 3 months of conventional treatment, followed by 3 months of autologous serum. Clinical assessments, including Schirmer's test, rose Bengal, and fluorescein staining, were carried out on entry and at monthly intervals. Impression cytology was performed at entry, 3 and 6 months. Grading was carried out on degrees of squamous metaplasia and goblet cell density. Subjective comfort was recorded daily using the "faces" scale. These categorical scores were converted to linear measurement using Rasch analysis. Statistical analysis was carried out using Wilcoxon's signed rank test and ANOVA. RESULTS: 16 patients were recruited with 31 eyes studied. The ocular surface diseases chiefly included Sjögren's syndrome (n = 6) and keratoconjunctivitis sicca (n = 5). Impression cytology available in 25 of 31 eyes showed significant improvement on serum treatment, p<0.02. Rasch weighted faces scores were statistically significantly better with serum, p<0.01. CONCLUSION: The results of this randomised study provide further evidence of the beneficial effects of autologous serum in severe ocular surface disorders. For most of these patients, autologous serum was superior to conventional treatment for improving ocular surface health and subjective comfort.
Adult↗
Contrast and glare testing in keratoconus and after penetrating keratoplasty.
AIM: 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. METHODS: 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. RESULTS: 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; p<0.01, post hoc Sheffé p<0.05), and the decrements to glare were no worse than for normals. The forme fruste keratoconus group were indistinguishable from normals on all measures. CONCLUSIONS: 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.
Adult↗
Late onset post-keratoplasty astigmatism in patients with keratoconus.
AIM: 10 eyes of 10 patients are reported where progression of keratoconus in the host cornea occurred more than 10 years after penetrating keratoplasty with resultant increase in astigmatism. The technique and results of graft refractive surgery in seven eyes are presented. METHODS: The clinical features and management of these patients were retrospectively analysed. Graft refractive surgery involved an incision at the graft-host junction adjacent to the host thinning with compressive resuturing. Astigmatic changes were calculated using vector analysis. RESULTS: There were seven men and three women with a mean age of 41.2 years. The average age when undergoing penetrating keratoplasty in the affected eye was 28.4 years and the average time after penetrating keratoplasty until keratoconus appeared in the host cornea defined by host thinning was 13.5 years. The mean cylinder power before host thinning was noted was 5.07 D (SD 2.19) and the mean after host thinning was 11.0 D (2.53). The mean vector calculated disease induced astigmatism magnitude was 7.59 D (3.09). Graft refractive surgery was performed in seven eyes. The mean cylinder power before and after graft refractive surgery was 11.28 D (2.15) and 7.09 D (5.53) respectively. The surgically induced astigmatism vector magnitude was 7.36 D (4.88). CONCLUSION: Progression of keratoconus in the host cornea late after penetrating keratoplasty is characterised by a large astigmatic change where the flat axis of astigmatism passes through an area of host thinning visible on slit lamp examination. Compressive resuturing performed in the area of host thinning resulted in satisfactory reduction of astigmatism.
Adult↗
The usefulness of Vistech and FACT contrast sensitivity charts for cataract and refractive surgery outcomes research.
AIM: To investigate the repeatability and sensitivity of two commonly used sine wave patch charts for contrast sensitivity (CS) measurement in cataract and refractive surgery outcomes. METHODS: The Vistech CS chart and its descendant, the Functional Acuity Contrast Test (FACT), were administered in three experiments: (1) Post-LASIK and age matched normal subjects; (2) Preoperative cataract surgery and age matched normal subjects; (3) Test-retest repeatability data in normal subjects. RESULTS: Contrast sensitivity was similar between post-LASIK and control groups and between the Vistech and FACT charts. The percentage of subjects one month post-LASIK achieving the maximum score across spatial frequencies (1.5, 3, 6, 12, 18 cycles per degree) were (50, 33, 13, 13, 0 respectively) for FACT, but only (0, 0, 13, 4, 0 respectively) for Vistech. A small number of cataract patients also registered the maximum score on the FACT, but up to 60% did not achieve the minimum score. Test-retest intraclass correlation coefficients varied from 0.28 to 0.64 for Vistech and 0.18 to 0.45 for FACT. Bland-Altman limits of agreement across spatial frequencies were between +/-0.30 and +/-0.85 logCS for Vistech, and +/-0.30 to +/-0.75 logCS for FACT. DISCUSSION: The Vistech was confirmed as providing poorly repeatable data. The FACT chart, likely because of a smaller step size, showed slightly better retest agreement. However, the reduced range of scores on the chart due to the smaller step size led to ceiling (post-LASIK) and floor (cataract) effects. These problems could mask subtle differences between groups of patients with near normal visual function as found post-refractive or cataract surgery. The Vistech and FACT CS charts are ill suited for refractive or cataract surgery outcomes research.
Adult↗
Refractive error changes in cortical, nuclear, and posterior subcapsular cataracts.
AIMS: To determine the effect of the three main morphological types of cataract on refractive error. METHODS: Data were prospectively collected from 77 subjects (age 67 (SD 8) years) with one morphological type of cataract. 34 had cortical, 21 had nuclear, and 21 had posterior subcapsular cataract. 22 subjects with clear lenses (60 (7) years) were recruited as controls. The spherical equivalent and astigmatic vector change between spectacle correction and optimal refraction were calculated. RESULTS: The cortical cataract group showed a significant astigmatic change of 0.71 (0.67) D (mean (1 SD)) compared to the control group (0.24 (0.20) D), with 24% outside the 95% confidence limit (0.63 D). The nuclear cataract group showed a significant myopic shift of -0.38 (0.60) D compared to the control group (+0.02 (0.21) D), with 52% beyond the minus 95% confidence limit (-0.39 D). CONCLUSION: A quarter of subjects with cortical cataract showed larger changes in astigmatism than subjects with clear lenses. This is probably because of the localised refractive index changes along cortical spoke opacities within the pupillary area. The well known myopic shift of nuclear cataract was also demonstrated.
Aged↗
Sorsby's fundus dystrophy.
BACKGROUND: Sorsby's fundus dystrophy describes the condition in which an autosomal-dominant inherited macular dystrophy with bilateral central visual loss is accompanied by progressive atrophy of the peripheral choroid and, subsequently, the outer retina. The first symptom of this condition is nyctalopia, whereas (typically) the first sign is the appearance of white-yellow deposits in the posterior pole. CASE REPORT: We report a case of Sorsby's fundus dystrophy, manifested with central visual loss in the fifth decade of life. A battery of tests--including ophthalmoscopy, electroretinography, color vision, Pelli-Robson contrast sensitivity, and fluorescein angiography--were used to evaluate the condition. CONCLUSIONS: While advances in understanding the etiology of Sorsby's fundus dystrophy have been made, the condition remains difficult to treat and the outcome is often devastating. The benefits of various methods of treatment, such as laser photocoagulation and dietary supplementation are unclear Patients affected by this condition should be managed in a manner similar to that for end-stage sufferers of age-related macular degeneration.
Adult↗
Penetrating keratoplasty for keratoconus: visual outcome and success.
OBJECTIVE: To determine the long-term effect on vision of penetrating keratoplasty performed for keratoconus. DESIGN: Retrospective noncomparative case series. PARTICIPANTS: All patients with keratoconus who received a corneal graft and who remained in our center for follow-up and visual rehabilitation during the study period. INTERVENTION: Penetrating keratoplasty was performed in 93 eyes of 78 patients. MAIN OUTCOME MEASURES: Graft survival, visual acuity, and astigmatism. RESULTS: One (1.08%) graft failure was encountered over a mean follow-up of 46 months. Mean preoperative (best corrected) and postoperative visual acuity is (best-tolerated correction) were 0.9 (20/160) and 0.24 (20/80) logMAR, respectively. Visual acuity in 86% of eyes was 0.3 logMAR (20/40) or better at the latest follow-up, with 67% of eyes being corrected with spectacles. Mean preoperative corneal power by keratometry was more than 52 diopters (D) in 83% of eyes; mean postoperative corneal power was 45 +/- 2 D. No significant predictors of postgraft astigmatism were found. Mean preoperative and postoperative best-eye acuities of the better eye were 0.32 (20/40-1) and 0.18 (20/32+1) logMAR, respectively (P < 0.001). CONCLUSIONS: Graft survival was excellent. A corrected visual acuity of 20/40 or better was obtained in 86% of eyes. Astigmatism could not be predicted from preoperative factors. Visual acuity measured in the better eye improved by 0.14 logMAR (1.4 lines), implying an overall functional gain for the patient.
Adolescent↗
Pseudoduplication of the optic nerve head.
BACKGROUND: Pseudo-doubling of the optic nerve head is a spectacular clinical entity, in which a lesion resembling an optic disk appears adjacent to the true optic disk. CASE REPORT: A case of unilateral pseudo-doubling of the optic disk with bilateral optic nerve pits is presented. CONCLUSIONS: The lesion is congenital, and represents a chorioretinal coloboma with optic disk involvement. Pseudo-doubling can be differentiated from true doubling of the optic nerve by the imaging techniques of ultrasonography, computerized tomography, and magnetic resonance imaging.
Aged↗
Localized scotomata detected with temporal modulation perimetry in central serous chorioretinopathy.
AIM: Flicker deficits have been reported in various maculopathies, including age-related macular degeneration. We test whether flicker losses exist in patients with central serous chorioretinopathy (CSC) and whether the size and flicker frequency of the target is important in detecting such losses. METHODS: We examined four CSC patients with temporal modulation (flicker perception) perimetry using the Medmont auto-flicker module (Medmont Pty Ltd, Melbourne, Vic. Australia), as well as static perimetry and colour vision. One case was examined using sophisticated laboratory equipment to precisely measure their temporal contrast sensitivity function (temporal CSF or de Lange curve) using larger targets to consider the effect of target frequency and size. Two patients were followed longitudinally and tested after resolution of the maculopathy. We compared our patients with an age-matched control group of 11 people. RESULTS: Temporal modulation perimetry detected larger and more localized defects in all cases of active CSC compared with static perimetry. There appeared to be size and frequency tuning to the deficit, with greatest loss being found at 16 Hz with small (0.5 degree) targets. The losses resolved in one case where the retina recovered in 4 weeks, but remained to a lesser degree in another case who suffered a 2 year long fluctuating course before the CSC subsided. CONCLUSIONS: Temporal modulation perimetry detects a loss of flicker sensitivity in patients with CSC. Deeper and more clearly defined scotomata are found with a flickering stimulus compared with a steady state one. The greatest losses of flicker sensitivity are found with 16 Hz modulation and with small targets located directly over the lesion. The duration of the disease may be important for recovery of flicker sensitivity. Temporal modulation perimetry appears to be a valuable tool for the confirmation of functional loss due to CSC.
Adult↗
Assessment of surgically induced astigmatism: toward an international standard.
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Astigmatism↗
Assessment of surgically induced astigmatism: toward an international standard II.
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Astigmatism↗
An instrument for assessment of subjective visual disability in cataract patients.
AIMS/BACKGROUND: The construction and validation of an instrument for the assessment of subjective visual disability in the cataract patient is described. This instrument is specifically designed for measuring the outcome of cataract surgery with respect to visual disability. METHODS: Visually related activities thought to be affected by cataract were considered for the questionnaire. These were reduced by pilot study and principal components analysis to 18 items. A patient's assessment of his/her ability to perform each task was scored on a four point scale. Scores were averaged to create an overall index of visual disability, as well as subscale indices for mobility related disability, distance/lighting/reading related disability, and near and related tasks visual disability. The questionnaire, administered verbally is entitled "The Visual Disability Assessment (VDA)". Reliability testing included test-retest reliability, interobserver reliability (p, the intraclass correlation coefficient), and internal consistency reliability (Cronbach's alpha). Construct validation, the process for proving that a test measures what it is supposed to measure, included consideration of content validity, comparison with the established Activities of Daily Vision Scale (ADVS) and empirical support with factor analysis. RESULTS: For the four indices, interobserver reliability varied from 0.92 to 0.94, test-retest reliability varied from 0.96 to 0.98, and internal consistency reliability varied from 0.80 to 0.93. The VDA compared favourably with the ADVS by correlation, but Bland-Altman analysis demonstrated that the two instruments were not clinically interchangeable. Factor analysis suggests that all test items measure a common theme, and the subgroupings reflect common themes. CONCLUSIONS: The VDA is easy to administer because it has a short test time and scoring is straightforward. It has excellent interobserver, test-retest, and internal consistency reliability, and compares favourably with the ADVS, another test of visual disability. Factor analysis demonstrated that the 18 items measure a related theme, which can be assumed to be visual disability. The VDA is a valid instrument which provides a comprehensive assessment of visual disability in cataract patients and is designed to detect changes within a patient over time.
Activities of Daily Living↗
Cataract surgery reduces subjective visual disability.
PURPOSE: The present study examines the impact of cataract on visual disability (VD) and how cataract surgery alters VD. METHODS: Fifty-six patients were assessed pre- and at 3 months post cataract surgery. Cataract severity was measured with the Lens Opacities Classification System III (LOCS III). Visual disability was assessed by questionnaire. The relationship between LOCS III scores and total VD score was examined with linear regression. Repeated measures analysis of variance was used to determine whether the pre- and postoperative VD scores were different. RESULTS: The VD score was found to relate more closely to the LOCS III score in the least affected eye than in the most affected eye. The VD score is related to nuclear opacity (P = 0.01), and posterior subcapsular cataract (PSC; P = 0.0004), but not to cortical cataract (P = 0.51) (r2 = 0.43). The VD score is significantly greater before surgery (mean +/- SD) 1.81 +/- 0.67) than after (1.19 +/- 0.21; P < 0.001). CONCLUSIONS: Nuclear and PSC cataracts cause more visual disability than cortical cataracts. Visual disability is significantly reduced by cataract surgery.
Cataract↗
Assessment of visual function in cataract patients with a mean visual acuity of 6/9.
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Analysis of Variance↗
Decreased uncorrected vision after a period of distance fixation with spectacle wear.
Myopes of low degree commonly report that their vision seems poorer upon removal of their spectacles compared to that after a period without spectacle wear. Notably, this difference in vision can be appreciated after distance fixation. In this paper, we propose and test several alternative hypotheses to explain the phenomenon: an accommodative response to spectacles, sensory adaptation, or altered criteria for blur of psychological origin. We measured visual acuity (VA), refractive error, and lens thickness on 10 subjects with less than 2.00 D of myopia. Testing was performed after two 90-min sessions viewing at distance. At one session, the subjects wore their current spectacle correction and, at the other session, no correction was worn. VA underwent a slight but significant decrease (0.4 of a line) after the session in which spectacles were worn, but no difference in refractive error or lens thickness was found. The change in acuity in the absence of a refractive shift suggests sensory adaptation to blur. However, the demonstrated change in VA appears to be less than that which is subjectively reported; accordingly, psychological input cannot be ruled out.
Accommodation, Ocular↗