Glaucoma screening by optometrists: Positive predictive value of visual field testing

Newman, D K; Anwar, Samira; Jordan, K

doi:10.1038/eye.1998.239

Cited by 33 publications

(33 citation statements)

References 19 publications

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“…2,4,5 Up to 12% of optometrist referrals were made for isolated VF loss in the absence of any glaucoma damage. 7,8 A separate study reported an increase in false-positive referrals from 1988 to 1993, and this was felt to be due to the increase in VF testing and to an increased willingness to refer patients at lower IOPs. 6 As referrals have been shown to be more accurate when IOP measurement, VF testing, and optic disc assessment were all performed, 2,3 it was important that any glaucoma detection programme involving optometrists should involve all three parameters.…”

Section: Discussionmentioning

confidence: 99%

The influence of the new general ophthalmic services (GOS) contract in optometrist referrals for glaucoma in Scotland

Ang

Azuara‐Blanco

2007

Eye

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Section: Discussionmentioning

confidence: 99%

The influence of the new general ophthalmic services (GOS) contract in optometrist referrals for glaucoma in Scotland

Ang

Azuara‐Blanco

2007

Eye

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“…Using a combination of all three investigations has been shown to have the highest positive predictive value (Bell and O'Brien, 1997;Newman et al, 1998;Harper and Reeves, 1999;Theodossiades and Murdoch, 1999). Glaucoma referrals pose a problem as highlighted in a recent audit (Vernon and Ghosh, 2001), which found that locally agreed guidelines for referral did not improve the true positive referral rate for glaucoma.…”

Section: Discussionmentioning

confidence: 99%

Assessment of information included on the GOS 18 referral form used by optometrists

Lash

2003

Ophthalmic Physiologic Optic

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Purpose: To audit the information included on GOS 18 forms used by UK optometrists when referring patients to an ophthalmologist. Methods: All GOS 18 forms received in a hospital ophthalmology department over a 10-week period were photocopied and the categories of information presented were recorded. Results: A total of 444 forms were analysed. The two most common referral categories were cataract 36.7% (n ¼ 163) and glaucoma 18.4% (n ¼ 82). Only 7% (n ¼ 11) of cataract referrals included details regarding effect on patient's lifestyle and willingness for surgery. Forty-seven per cent (n ¼ 77) of referrals for cataract resulted in patients being listed for surgery. Eighty-two per cent (n ¼ 67) of referrals for glaucoma included disc assessment, intraocular pressure and visual fields. Five per cent (n ¼ 22) of optometrists gained the patients' consent for release of clinical information. Thirty-one per cent (n ¼ 137) of forms had no practitioner name and 6% (n ¼ 27) gave no practice address. Conclusion: Information included on GOS 18 forms could be improved with regard to cataract referrals. Feedback from ophthalmologists would be facilitated by inclusion of practitioner/practice details, and by completion of the consent section on the GOS 18.

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“…There is no formal screening programme for glaucoma in the UK, so detection is largely dependent on the public attending an optometrist for sight testing, with optometrists responsible for over 90% of referrals to the Hospital Eye Service. [5][6][7][8] Three tests/examinations are recommended for the detection of glaucoma; measurement of IOP, visual field and optic disc assessment. However, optometrist case-finding and referral criteria vary considerably across the profession.…”

mentioning

confidence: 99%

“…11 Recent studies have reported positive predictive values (PPV) of optometrist referrals for glaucoma ranging between 0.31 and 0.50. 5,7,9,[11][12][13][14] As PPV is directly related to prevalence and prevalence is low, this figure implies that optometrist referrals have a high degree of specificity. 15 The proportion of undetected glaucoma in the developed world, however, remains at about 50%.…”

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confidence: 99%

Glaucoma case finding: a cluster-randomised intervention trial

Theodossiades

Murdoch

2004

Eye

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Purpose To assess the effect of an intervention comprising training in optic disc assessment, explicit referral criteria and ophthalmologist feedback on referred patients, on the number of optometrist referrals for suspected glaucoma seen at a referral site and the positive predictive value of those referrals. Methods Optometric practices routinely referring to the Ealing Hospital Eye Clinic were randomly divided into two groups taking into consideration those practices, which shared an optometrist (a cluster) and the number of optometrist days worked per week. One group of practices acted as controls, while the other practices were invited to receive the intervention. Data on 397 new patients referred and presenting to Ealing Hospital with suspected glaucoma were collected over a 20-month period. The data on patients who had failed to attend their appointment were collected over 7 months of this period. The number of referrals seen, the positive predictive value of those referrals, and the attendance rate were calculated. Optometrist's opinions of the intervention were assessed qualitatively. Data relating to optometrist compliance with the intervention were also collected. Results The number of glaucoma referrals presenting to Ealing Hospital from the intervention practices was almost double that from the control practices (210 vs 119). When cluster randomisation, the number of optometrist days per cluster and the number of assessed referrals in the preintervention period are taken into consideration, it is estimated that the intervention is associated with a 52% increase in the number of referrals reaching Ealing Hospital. However, the design effect resulting from the cluster randomisation was unexpectedly high (of the order of [13][14] and so the confidence intervals around the estimate of 52% are very wide (95% c.i. 35% decrease to 253% increase, P ¼ 0.34). There was no evidence of an association between optometrist compliance with the intervention and the number of referrals seen at Ealing Hospital. The positive predictive value (PPV) of referrals was similar for the intervention (0.49 (95% c.i. 0.42, 0.55)) and control groups (0.46 (95% c.i. 0.33, 0.60)). Optometrist opinions of the intervention were largely favourable. All expressed a willingness to participate in future programmes. Conclusion A large difference in the number of referrals between the practice groups was observed. Since the PPV of referral was unchanged, the potential impact of the intervention in terms of numbers of new cases of glaucoma detected in the community is substantial. However, because of its large design effect, this trial does not provide conclusive evidence of an impact of the intervention on referral numbers. A considerably larger trial will be required to produce conclusive evidence of an effect.

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Glaucoma screening by optometrists: Positive predictive value of visual field testing

Abstract: Visual field testing is currently leading to unnecessary referrals to the hospital eye service with no detectable improvement in the accuracy of glaucoma suspect referrals. It is important that optometrists perform visual field testing in accordance with validated screening methodology.

Cited by 33 publications

References 19 publications

The influence of the new general ophthalmic services (GOS) contract in optometrist referrals for glaucoma in Scotland

The influence of the new general ophthalmic services (GOS) contract in optometrist referrals for glaucoma in Scotland

Assessment of information included on the GOS 18 referral form used by optometrists

Glaucoma case finding: a cluster-randomised intervention trial

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