Robert Harper

Enhanced low vision rehabilitation for people with age related macular degeneration: A randomised controlled trial

Aim: To compare the effectiveness of three models of low vision rehabilitation for people with age related macular degeneration (AMD) referred for low vision rehabilitation (LVR): (a) an enhanced low vision rehabilitation model (ELVR) including supplementary home based low vision rehabilitation; (b) conventional low vision rehabilitation (CLVR) based in a hospital clinic; (c) CLVR with home visits that did not include rehabilitation (CELVR), intended to act as a control for the additional contact time with ELVR. Method: A single centre parallel group randomised controlled trial in participants’ homes and the low vision clinic, Manchester Royal Eye Hospital. People referred for LVR with a primary diagnosis of AMD and visual acuity worse than 6/18 in both eyes and equal to or better than 1/60 in the better eye. The main outcome measures were vision specific quality of life (QoL) (primary outcome, VCM1) and generic health related QoL (SF-36); psychological adjustment to vision loss; measured task performance; restriction in everyday activities; use of low vision aids (LVAs). Results: 226 participants were recruited (median age 82 years); 194 completed the trial (86%). Except for SF-36 physical and mental component summary scores, arms did not differ significantly for any of the outcomes. Differences for the VCM1 were ELVR v CLVR, 0.06 (95% CI to 0.17 to 0.30, p = 0.60); ELVR v CELVR, 0.12 (95% CI to 0.11 to 0.34, p = 0.31); CELVR v CLVR, –0.05 (95% CI –0.29 to 0.18, p = 0.64). Differences for the SF-36 favoured CLVR compared to ELVR (ELVR v CLVR: physical = –6.05, 95% CI –10.2 to –1.91, p = 0.004; mental = –4.04, 95% CI –7.44 to –0.65, p = 0.02). At 12 months, 94% of participants reported using at least one LVA. Conclusion: ELVR was no more effective than CLVR. Researchers should be wary of proposing new LVR interventions without preliminary evidence of effectiveness, given the manifest lack of effectiveness of the model of enhanced LVR evaluated in the trial.

How Effective is Low Vision Service Provision? A Systematic Review

Visual impairment is a large and growing socioeconomic problem. Good evidence on rehabilitation outcomes is required to guide service development and improve the lives of people with sight loss. Of the 478 potentially relevant articles identified, only 58 studies met our liberal inclusion criteria, and of these only 7 were randomized controlled trials. Although the literature is sufficient to confirm that rehabilitation services result in improved clinical and functional ability outcomes, the effects on mood, vision-related quality of life (QoL) and health-related QoL are less clear. There are some good data on the performance of particular types of intervention, but almost no useful data about outcomes in children, those of working age, and other groups. There were no reports on cost effectiveness. Overall, the number of well-designed and adequately reported studies is pitifully small; visual rehabilitation research needs higher quality research. We highlight study design and reporting considerations and suggest a future research agenda.

Face recognition in age related macular degeneration: perceived disability, measured disability, and performance with a bioptic device.

Aims: (1) To explore the relation between performance on tasks of familiar face recognition (FFR) and face expression difference discrimination (FED) with both perceived disability in face recognition and clinical measures of visual function in subjects with age related macular degeneration (AMD). (2) To quantify the gain in performance for face recognition tasks when subjects use a bioptic telescopic low vision device. Methods: 30 subjects with AMD (age range 66–90 years; visual acuity 0.4–1.4 logMAR) were recruited for the study. Perceived (self rated) disability in face recognition was assessed by an eight item questionnaire covering a range of issues relating to face recognition. Visual functions measured were distance visual acuity (ETDRS logMAR charts), continuous text reading acuity (MNRead charts), contrast sensitivity (Pelli-Robson chart), and colour vision (large panel D-15). In the FFR task, images of famous people had to be identified. FED was assessed by a forced choice test where subjects had to decide which one of four images showed a different facial expression. These tasks were repeated with subjects using a bioptic device. Results: Overall perceived disability in face recognition did not correlate with performance on either task, although a specific item on difficulty recognising familiar faces did correlate with FFR (r = 0.49, p<0.05). FFR performance was most closely related to distance acuity (r = −0.69, p<0.001), while FED performance was most closely related to continuous text reading acuity (r = −0.79, p<0.001). In multiple regression, neither contrast sensitivity nor colour vision significantly increased the explained variance. When using a bioptic telescope, FFR performance improved in 86% of subjects (median gain = 49%; p<0.001), while FED performance increased in 79% of subjects (median gain = 50%; p<0.01). Conclusion: Distance and reading visual acuity are closely associated with measured task performance in FFR and FED. A bioptic low vision device can offer a significant improvement in performance for face recognition tasks, and may be useful in reducing the handicap associated with this disability. There is, however, little evidence for a correlation between self rated difficulty in face recognition and measured performance for either task. Further work is needed to explore the complex relation between the perception of disability and measured performance.

Quality of life in myopia

BACKGROUND The safety and predictability of refractive surgery for all degrees of myopia is now becoming established. It is therefore appropriate to evaluate whether there is a patient driven demand for such treatments and, if so, to establish guidelines for its provision within the National Health Service (NHS). METHODS A comparative study was designed to assess the effect of degree of myopia on quality of life (“high” (n = 30) –10.00D, worse eye; “moderate” (n = 40) –4.00 to –9.75D, worse eye; “low” (n = 42) <–4.00D, worse eye) compared with a group of patients with keratoconus (n = 30) treated by optical correction. Data collection included binocular logMAR visual acuity, Pelli-Robson low contrast letter sensitivity, questionnaires to assess subjective visual function (VF-14) and effect on quality of life (VQOL), and semi-structured interviews. RESULTS There were no significant differences in any of the measures between patients with a high degree of myopia and those with keratoconus, or between those with a low and those with a moderate degree of myopia. However, those with a high degree of myopia had highly significantly poorer logMAR, VF-14, and VQOL scores than those with low and moderate myopia (p<0.001). Interview data supported these findings with patients with a high degree of myopia and those with keratoconus reporting that psychological, cosmetic, practical, and financial factors affected their quality of life. CONCLUSION Compared with low and moderate myopia, patients with a high degree of myopia experience impaired quality of life similar to that of patients with keratoconus. Criteria should therefore be identified to enable those in sufficient need to obtain refractive surgical treatment under the NHS.

Community refinement of glaucoma referrals

AbstractAim To describe a Manchester-based glaucoma referral refinement scheme designed to reduce the number of false-positive referrals to the hospital eye service. To report on the first years results of this scheme and its financial costs to the NHS.Methods Patients with suspected glaucoma, instead of being referred to their GP and then on to the hospital eye service, were referred to a group of specially trained community optometrists working to an agreed set of referral criteria. Those patients who did not meet the referral criteria were returned to the referring optometrist, while those who met the referral criteria were referred directly to Manchester Royal Eye Hospital. The patients GP was informed in all cases.Results The number of suspect glaucoma cases referred to the Manchester Royal Eye Hospital was reduced by 40%. This figure is close to the percentage of false-positive referrals measured at Manchester Royal Eye Hospital prior to the onset of this study. The information accompanying referral has been improved and the scheme produces a small financial cost saving to the NHS of approximately £17 per patient.Conclusion Community refinement of suspect glaucoma offers some important benefits over the current referral pathway.

Evaluating the outcomes of low vision rehabilitation

The requirement for those providing healthcare to measure outcomes raises the fundamental question of how these should be measured. Both the scale of the low vision population and the different models of care proposed make it a pressing need to determine outcomes using valid and reliable measures. In this study we describe the development and piloting of a questionnaire designed to meet this requirement. The questionnaire was piloted on 56 subjects with age‐related macular degeneration (ARMD). Test‐retest reliability of the questionnaire was estimated using a further sample of 28 subjects with ARMD. Pilot testing confirmed the feasibility of administering the questionnaire to an elderly population with ARMD. A total of 87% of the sample reported using an LVA (65% on a daily basis), predominantly for a reading task. The number of tasks an LVA was used for, its frequency of use, length of continuous use and ease of use are significantly associated with the rating of an LVA as important/less important (P<0.0001), but the acuity achieved with the device is not significantly associated with rated importance (P=0.11), reinforcing doubt about the validity of visual function outcomes. The limitations of this pilot study and earlier case series in describing the outcomes of low vision care are discussed and a randomised controlled trial using a broad range of outcomes is proposed in order to fully describe the effectiveness of low vision rehabilitation and inform the debate about models of care.

Visual function after penetrating keratoplasty for keratoconus: a prospective longitudinal evaluation

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 (p<0.05); disability glare (p<0.05) no longer had a significant detrimental effect on these variables. VF-14 score improved significantly throughout the postoperative period (p<0.05). There was significant correlation of the VF-14 score with aided visual acuity, binocular visual field, and stereoacuity. Postoperative astigmatism (<4Dv >4D) 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.

The sensitivity and specificity of direct ophthalmoscopic optic disc assessment in screening for glaucoma: a multivariate analysis

Abstract Background: Previous studies have shown that the cup:disc (C/D) ratio has limited sensitivity and specificity. Improved sensitivity and specificity has been found with combinations of disc parameters using stereophotography or disc imaging, but the extent to which these studies reflect what can be achieved by direct assessment is unclear. The purpose of this paper is to report the sensitivities and specificities of a range of disc parameters, both in isolation and in combination, as graded during clinical examination with direct ophthalmoscopy. Methods: Sixty-seven patients with newly diagnosed primary open angle glaucoma and 145 non-glaucomatous subjects were examined by direct ophthalmoscopy. The following features of the optic disc were graded: vertical and horizontal C/D ratios (uncorrected for disc size), narrowest rim width, presence/absence of disc haemorrhage, focal pallor of the neuroretinal rim, parapapillary atrophy, steepness of the cup-edge and presence/absence of baring of the lamina cribrosa. Subjects were validated as glaucomatous/non- glaucomatous on the basis of visual fields, independently of the results of optic disc gradings. Multiple logistic regression modelling was used to evaluate the effectiveness of combinations of disc parameters. Results: Sensitivities and specificities are limited for all features when considered in isolation. The ’cupping’ parameters have the highest sensitivities and specificities but no single cut-off criterion for these parameters has both high sensitivity and specificity. Multiple logistic regression modelling indicated that two disc parameters in combination, narrowest rim width and parapapillary atrophy, were independently associated with glaucoma and achieved best prediction. Combining information from these parameters achieved a sensitivity of 81% (95% CI=69–89%) and a specificity of 90% (95% CI=84–95%), a level of discrimination that is not significantly better than narrowest rim width alone in terms of area under the receiver operator characteristic (ROC) curve. Conclusion: Disc assessment during clinical examination with direct ophthalmoscopy can achieve comparable sensitivities and specificities with those previously reported for stereophotographic assessment or visual fields screening. However, since the diagnostic accuracy of disc assessment in isolation is inadequate for screening, a combined test strategy is necessary.

Glaucoma screening: the importance of combining test data.

The objective of this study was to evaluate the effectiveness of screening tests for primary open angle glaucoma, both singly and in combination, using a decision analysis approach. A range of screening tests were carried out on 145 nonglaucomatous patients and 67 cases of previously undiagnosed glaucoma. Receiver operator characteristic curves were constructed for single test data to show the trade-off between sensitivity and specificity for varying cut-off criteria. The best discriminators of glaucoma were, in rank order: (1) a multiple stimulus static visual field screening test, (2) optic disc cupping, and (3) intraocular pressure. Decision curves were also constructed for various combinations of screening tests, where the inclusion of the tests were based on discriminant analyses. Sensitivities and specificities of more than 0.90 were obtained when visual field screening, optic disc cupping, and intraocular pressure were combined. Data from other tests when combined with these three variables failed to provide a significant improvement in discrimination.

Observer variability in optic disc assessment: implications for glaucoma shared care

Demonstrating that optometrists can make valid and reliable assessments of optic disc features is an important prerequisite for establishing schemes for shared care/co-management. Previous studies have estimated observer variability among experts in the assessment of optic disc cupping, but there has been a paucity of information on observer variability amongst optometrists. This paper describes a study to investigate intra- and inter-observer variability for a range of disc features, as graded by both ophthalmologists and optometrists. Five observers (three optometrists and two ophthalmologists) graded 48 stereo-pairs of optic disc photographs from 48 patients on two separate occasions. Each observer graded the following features: vertical and horizontal C/D ratios, narrowest rim width, the presence/absence of a disc haemorrhage, focal pallor of the neuroretinal rim, peri-papillary atrophy, the steepness of the cup-edge and the presence/absence of the cribriform sign. The average intra- and inter-observer standard deviation (SD) of differences are, respectively, 0.11 and 0.19 for the vertical C/D ratios and 0.10 and 0.18 for the horizontal C/D ratios. For the vertical C/D ratio the average weighted kappa (kappa w) is 0.79 within observers and 0.46 between observers. Percentage agreements for the presence/absence of a disc haemorrhage range from 96 to 100% (average kappa = 0.92) within observers and from 90 to 98% (average kappa = 0.77) between observers. For other disc features, average kappa w values range from 0.67 to 0.71 within observers and from 0.23 to 0.46 between observers. Intra- and inter-observer comparisons (within and between different professionals) across all disc features are comparable for the optometrists and ophthalmologists, thus demonstrating that optometrists can make valid assessments of disc features. The implications for shared care are discussed.