An analysis of referral routes and diagnostic accuracy in cases of suspected glaucoma

The quality, accuracy and appropriateness of UK optometric age-related macular degeneration referrals

PURPOSE

Little is known about the quality of optometrists' referrals to secondary care for neovascular age-related macular degeneration (nAMD), despite the need for timely intervention. We analysed the content and accuracy of optometrists' referrals for nAMD. Adherence to UK National Institute for Health and Care Excellence (NICE) guidelines and the impact of the COVID-19 pandemic were assessed as secondary measures.

METHODS

Optometric referrals to a specialist macular treatment centre in Bradford, United Kingdom, between March 2019 and March 2021 were retrospectively analysed and compared with subsequent electronic medical records. Data were extracted on legibility, reason for referral, patient and optometrist demographics, visual acuity, reported signs and symptoms, patient diagnosis and patient outcomes. Binomial logistic regression models were constructed to determine whether signs or symptoms noted in the referral were associated with subsequent nAMD diagnosis in secondary care and whether optometrist gender or experience influenced nAMD referral accuracy.

RESULTS

Across all 394 referrals analysed, 256 were for nAMD. Referral accuracy for nAMD was 39.8% (95% CI [34.0%, 45.9%]), with the most common reason for misdiagnosis being dry AMD. However, 76.8% of patients referred for suspected nAMD were either treated in secondary care or observed over multiple visits. 20% of suspected nAMD patients were seen within the NICE recommended 14-day window pre-COVID, dropping to 5% during the pandemic (p < 0.001). Visual acuity was most strongly associated with nAMD diagnosis (χ2(1) = 13.71, p < 0.001) followed by macular haemorrhage (χ2(1) = 5.89, p = 0.02). Neither optometrist gender nor experience was significantly associated with confirmed nAMD. Legibility of referrals was 91-95% for patient details and 94-97% for the referring optometrist.

CONCLUSIONS

Although the overall quality and legibility of optometrists' macular referrals to secondary care were of a high standard, the diagnostic accuracy of nAMD was below 40%. Referred visual acuity was the main sign/symptom associated with confirmed nAMD diagnosis.

Glaucoma: what the neurologist needs to know

Glaucoma is a progressive optic neuropathy resulting from pathological changes at the optic disc due to elevated intraocular pressure. Its diagnosis, treatment and follow-up are almost entirely conducted in ophthalmology clinics, with screening conducted by community optometrists. Despite this, neurologists may encounter glaucoma in both its acute presentation (as angle closure, presenting as acute headache) and its chronic forms (often as optic neuropathy of unknown cause). An awareness of the underlying pathological process, and the key distinguishing signs and symptoms, will allow neurologists to identify the glaucomatous process rapidly. Timely referral is essential as glaucoma invariably results in progressive visual loss without treatment. This review therefore condenses the wide field of glaucoma into a practical summary, aimed at practitioners with limited clinical experience of this ophthalmic condition.

Outcomes of newly referred patients with suspected angle closure: do we need to redefine the clinical pathways?

BACKGROUND/OBJECTIVES

To investigate outcomes of referrals for suspected angle closure and explore whether anterior segment optical coherence tomography (AS-OCT) can be used to tighten triaging criteria in a glaucoma virtual clinic.

SUBJECTS/METHODS

Retrospectively collected data. The first audit (04/2018-03/2019) identified referrals for suspected angle closure without other glaucoma-related findings (primary angle closure suspect (PACS) referrals). All patients underwent gonioscopy. The second audit (04-08/2019) identified patients with suspected angle closure in a virtual clinic. Management outcomes were assessed, using gonioscopy as reference standard. The outcomes of the second audit were re-audited after changing the triaging criterion from angle width <10° to iridotrabecular contact (ITC) in ≥1 quadrants on AS-OCT.

RESULTS

Out of 1754 glaucoma referrals (first audit), 24.6% (431/1754) were PACS referrals. Of these, only 10.7% (42/393) had an occludable angle on gonioscopy, with 97.6% (41/42) being PACS. Of these, 78% (32/41) underwent laser peripheral iridotomy. Out of 137 referrals in the virtual clinic (second audit), 66.4% (91/137) were triaged to the face-to-face clinic. Of these, 31.9% (29/91) were discharged. AS-OCT had positive and negative predictive value of 74.3% (95% confidence intervals (CI) 57.8-86.0) and 82.1% (95% CI 70.0-90.2%), respectively, in detecting ITC in ≥1 quadrants. In the re-audit 45.9% (45/98) of those with suspected angle closure were triaged for gonioscopy, with 24.4% (11/45) of them being discharged.

CONCLUSION

PACS referrals represent a substantial burden to hospital-based services and their accuracy is low. ITC in ≥1 quadrants on AS-OCT can be useful in triaging those who need further evaluation with gonioscopy.

Effects of socioeconomic status on baseline values and outcomes at 24 months in the Treatment of Advanced Glaucoma Study randomised controlled Trial

BACKGROUND/AIMS

Socioeconomic status (SES) is associated with late disease presentation and poorer outcomes. We evaluate the effect of SES on treatment outcomes and report the correlation between SES and baseline characteristics of participants in the Treatment of Advanced Glaucoma Study.

METHODS

Pragmatic multicentre randomised controlled trial. Four hundred and fifty-three patients presenting with advanced open-angle glaucoma in at least one eye (Hodapp-Parrish-Anderson classification). Participants were randomised to either glaucoma drops (medical arm) or trabeculectomy (surgery arm). Clinical characteristics, Quality of life measurement (QoL) and SES defined by the Index of Multiple Deprivation are reported. Subgroup analysis explored treatment effect modifications of SES at 24 months. Correlation between SES and baseline characteristics was tested with the χ2 test of association for dichotomous variables and pairwise Pearson's correlation for continuous variables.

RESULTS

The mean visual field mean deviation was -17.2 (6.7)dB for the most deprived quintile of participants and -13.0 (5.5) for the least deprived quintile in the index eye. At diagnosis, there was a strong correlation between SES and ethnicity, age, extent of visual field loss and number of visits to opticians prior to diagnosis. At 24 months, there was no evidence that the treatment effect was moderated by SES.

CONCLUSIONS

In patients presenting with advanced glaucoma. SES at baseline is correlated with poorer visual function, poorer Visual Function Questionnaire-25 QoL, ethnicity, age and number visits to an optician in the years preceding diagnosis. SES at baseline does not have an effect of the success of treatment at 24 months.

TRIAL REGISTRATION NUMBER

ISRCTN56878850.

Measures of multiple deprivation and visual field loss in glaucoma clinics in England: lessons from big data

BACKGROUND/OBJECTIVES

To examine the association between multiple deprivation with late diagnosis and rapid worsening of glaucoma in patients in English hospital eye services (HES).

METHODS

602,439 visual fields (VFs) were extracted from five regionally different glaucoma clinics in England. Mean Deviation (MD) worse than -12 dB was used as a surrogate definition for advanced VF loss at diagnosis in patients with ≥2 reliable VF records. MD loss worse than -1 dB per year was used to define rapid VF progression in patients with ≥6 VFs. Patient data were stratified into deciles of the Index of Multiple Deprivation (IMD) from residential postcodes.

RESULTS

There was an association between IMD and advanced VF loss at diagnosis in 44,956 patients with 18% (293/1608) and 11% (771/6929) in the most and least deprived IMD decile, respectively. Age-corrected odds ratio (OR) for having advanced VF loss at entry into HES was 1.42 (95% confidence interval [CI] 1.21-1.67) and 0.75 (95% CI: 0.66-0.85) in the most and least deprived IMD decile respectively (reference = fifth decile). In 15,094 patients with follow up data (median [interquartile range] of 6.9 [4.5, 10.0] years), the proportion having rapid VF progression did not differ across the IMD spectrum.

CONCLUSION

Large-scale VF data from clinics indicates that glaucoma severity at presentation to English HES is associated with levels of multiple deprivation. We found no evidence to suggest likelihood of having rapid VF progression during follow-up is associated with IMD; this hints at equity of glaucoma care and outcomes once patients are in English HES.

Primary trabeculectomy versus primary glaucoma eye drops for newly diagnosed advanced glaucoma: TAGS RCT

BACKGROUND

Patients diagnosed with advanced primary open-angle glaucoma are at a high risk of lifetime blindness. Uncertainty exists about whether primary medical management (glaucoma eye drops) or primary surgical treatment (augmented trabeculectomy) provide the best and safest patient outcomes.

OBJECTIVES

To compare primary medical management with primary surgical treatment (augmented trabeculectomy) in patients with primary open-angle glaucoma presenting with advanced disease in terms of health-related quality of life, clinical effectiveness, safety and cost-effectiveness.

DESIGN

This was a two-arm, parallel, multicentre, pragmatic randomised controlled trial.

SETTING

Secondary care eye services.

PARTICIPANTS

Adult patients presenting with advanced primary open-angle glaucoma in at least one eye, as defined by the Hodapp-Parrish-Anderson classification of severe glaucoma.

INTERVENTION

Primary medical treatment - escalating medical management with glaucoma eye drops. Primary trabeculectomy treatment - trabeculectomy augmented with mitomycin C.

MAIN OUTCOME MEASURES

The primary outcome was health-related quality of life measured with the Visual Function Questionnaire-25 at 2 years post randomisation. Secondary outcomes were mean intraocular pressure; EQ-5D-5L; Health Utilities Index 3; Glaucoma Utility Index; cost and cost-effectiveness; generic, vision-specific and disease-specific health-related quality of life; clinical effectiveness; and safety.

RESULTS

A total of 453 participants were recruited. The mean age of the participants was 67 years (standard deviation 12 years) in the trabeculectomy arm and 68 years (standard deviation 12 years) in the medical management arm. Over 65% of participants were male and more than 80% were white. At 24 months, the mean difference in Visual Function Questionnaire-25 score was 1.06 (95% confidence interval -1.32 to 3.43; p = 0.383). There was no evidence of a difference between arms in the EQ-5D-5L score, the Health Utilities Index or the Glaucoma Utility Index. At 24 months, the mean intraocular pressure was 12.40 mmHg in the trabeculectomy arm and 15.07 mmHg in the medical management arm (mean difference -2.75 mmHg, 95% confidence interval -3.84 to -1.66 mmHg; p < 0.001). Fewer types of glaucoma eye drops were required in the trabeculectomy arm. LogMAR visual acuity was slightly better in the medical management arm (mean difference 0.07, 95% confidence interval 0.02 to 0.11; p = 0.006) than in the trabeculectomy arm. There was no evidence of difference in safety between the two arms. A discrete choice experiment updated the utility values for the Glaucoma Utility Index. The within-trial economic analysis found a small increase in the mean EQ-5D-5L score (0.04) and that trabeculectomy has a higher probability of being cost-effective than medical management. The incremental cost of trabeculectomy per quality-adjusted life-year was £45,456. Therefore, at 2 years, surgery is unlikely to be considered cost-effective at a threshold of £20,000 per quality-adjusted life-year. When extrapolated over a patient's lifetime in a model-based analysis, trabeculectomy, compared with medical treatment, was associated with higher costs (average £2687), a larger number of quality-adjusted life-years (average 0.28) and higher incremental cost per quality-adjusted life-year gained (average £9679). The likelihood of trabeculectomy being cost-effective at a willingness-to-pay threshold of £20,000 per quality-adjusted life year gained was 73%.

CONCLUSIONS

Our results suggested that there was no difference between treatment arms in health-related quality of life, as measured with the Visual Function Questionnaire-25 at 24 months. Intraocular pressure was better controlled in the trabeculectomy arm, and this may reduce visual field progression. Modelling over the patient's lifetime suggests that trabeculectomy may be cost-effective over the range of values of society's willingness to pay for a quality-adjusted life-year.

FUTURE WORK

Further follow-up of participants will allow us to estimate the long-term differences of disease progression, patient experience and cost-effectiveness.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN56878850.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 72. See the NIHR Journals Library website for further project information.

Visual field-based grading of disease severity in newly diagnosed primary open angle glaucoma patients presenting to a tertiary eye care centre in India

PURPOSE

To evaluate the severity of primary open angle glaucoma (POAG) at presentation using visual field analysis and its relationship to demographic and ocular factors in patients presenting to a tertiary eye care centre.

DESIGN

Cross-sectional study.

METHODS

Newly diagnosed POAG patients were classified as early, moderate, or severe stage in the worse eye based on the Humphrey visual field testing using Hodapp-Parrish-Andersons criteria. The groups were compared for differences in demographics and ocular characteristics. Statistical analysis was done using STATA 14.1 (Texas, USA).

RESULTS

The average age of 71 eligible patients was 60.04 ± 9.53 years, and the cohort had 29.5% females. Among the subjects, 19 (26.7%) had early, 24 (33.3%) had moderate and 28 (38.89%) had severe POAG at presentation. There was no statistically significant difference among different stages of glaucoma with respect to age and sex groups. No statistical association was found with education, occupation status, presenting complaints, family history of glaucoma, or systemic diseases between the different stages of severity. 5.6% with severe disease presented with a relative afferent pupillary defect (RAPD). The mean intraocular pressure (IOP) in the severe stage was 22.54 ± 5.27 mmHg, which was not statistically higher than the other groups (P = 0.726).

CONCLUSIONS

Newly diagnosed POAG patients predominantly present at moderate or severe stage of disease, reflecting either the asymptomatic nature of the disease or a lack of access to vision care services. Existing screening programmes need to be improved, with special attention to women and individuals less than 50 years of age.

Baseline Characteristics of Participants in the Treatment of Advanced Glaucoma Study: A Multicenter Randomized Controlled Trial

PURPOSE

To report the baseline characteristics of participants enrolled in TAGS (Treatment of Advanced Glaucoma Study).

DESIGN

Pragmatic randomized control trial (RCT).

METHODS

Participants with newly diagnosed advanced glaucoma in at least 1 eye were recruited. Participants were patients with open angle glaucoma presenting with advanced glaucoma in at least 1 eye as defined by the Hodapp-Parrish-Anderson (HPA) criteria for severe defect. Participants were randomly allocated to receive either primary augmented trabeculectomy or primary medical management. When both eyes were eligible, the same intervention was undertaken in both eyes, and the index eye for analysis was the eye with the less severe visual field mean defect (MD). Main outcome measurements were visual field profile, defined by the HPA classification; clinical characteristics; quality of life, as measured by the National Eye Institute Visual Function Questionnaire 25 (VFQ-25), the EuroQual-5 Dimension (EQ-5D 5L), Health Utility Index-3 (HUI-3), and the Glaucoma Profile Instrument (GPI).

RESULTS

A total of 453 patients were recruited. The mean visual field MD was -15.0 dB ± 6.3 in the index eye and -6.2 dB in the non-index eye. Of index eyes (HPA "severe" classification) at baseline, more than 70% of participants had a MD <-12.00 dB, and nearly 90% had more than 20 points defective at the 1% level. The mean LogMAR visual acuity of the index eye was 0.2 ± 0.3.

CONCLUSIONS

TAGS is the first RCT to compare medical versus surgical treatments for patients presenting with advanced open angle glaucoma in a publicly funded health service. The study will provide clinical, health-related quality of life, and economic outcomes to inform future treatment choices for those presenting with advanced glaucoma.

Advanced glaucoma at diagnosis: current perspectives

Presentation with advanced glaucoma is a significant risk factor for lifetime blindness. The asymptomatic nature of glaucoma, particularly in early disease, means that substantial vision loss in one eye does not always translate into a perceptible loss of visual function. This, along with the lack of an effective screening strategy, contributes to late presentation. Those most at risk of presenting with advanced glaucoma have asymptomatic high intraocular pressure (IOP), no family history of glaucoma, are socially disadvantaged, and do not attend sight testing. Patients with glaucoma may have impaired functionality for daily activities, such as reading, walking and driving. Quality of life measures have shown this to be significantly worse in patients with more severe visual field loss, particularly if bilateral. In addition, quality of life decreases faster with further bilateral visual field loss when advanced visual field damage is present. Management of these patients requires disproportionally more resources than those with earlier disease. Both medical and surgical options are used as the initial approach to treat patients presenting with advanced glaucoma. The most recently published National Institute for Health and Care Excellence (NICE) guidelines suggest that patients presenting with advanced disease should be offered trabeculectomy as a primary intervention. However, more evidence is required to determine the best initial management. The Treatment of Advanced Glaucoma Study (TAGS) is being conducted, comparing primary medical management with primary mitomycin C-augmented trabeculectomy for people presenting with advanced open-angle glaucoma. The results of TAGS will provide robust evidence for the most appropriate initial intervention.

Care pathways for glaucoma detection and monitoring in the UK

Glaucoma presents considerable challenges in providing clinically and cost-effective care pathways. While UK population screening is not seen as justifiable, arrangements for case finding have historically been considered relatively ineffective. Detection challenges include an undetected disease burden, whether from populations failing to access services or difficulties in delivering effective case-finding strategies, and a high false positive rate from referrals via traditional case finding pathways. The enhanced General Ophthalmic Service (GOS) in Scotland and locally commissioned glaucoma referral filtering services (GRFS) elsewhere have undoubtedly reduced false positive referrals, and there is emerging evidence of effectiveness of these pathways. At the same time, it is recognised that implementing GRFS does not intrinsically reduce the burden of undetected glaucoma and late presentation, and obvious challenges remain. In terms of diagnosis and monitoring, considerable growth in capacity remains essential, and non-medical health care professional (HCP) co-management and virtual clinics continue to be important solutions in offering requisite capacity. National guidelines, commissioning recommendations, and the Common Clinical Competency Framework have clarified requirements for such services, including recommendations on training and accreditation of HCPs. At the same time, the nature of consultant-delivered care and expectations on the glaucoma specialist's role has evolved alongside these developments. Despite progress in recent decades, given projected capacity requirements, further care pathways innovations appear mandated. While the timeline for implementing potential artificial intelligence innovations in streamlining care pathways is far from established, the glaucoma burden presents an expectation that such developments will need to be at the vanguard of future developments.

Clinical effectiveness of the Manchester Glaucoma Enhanced Referral Scheme

Background

Glaucoma referral filtering schemes have operated in the UK for many years. However, there is a paucity of data on the false-negative (FN) rate. This study evaluated the clinical effectiveness of the Manchester Glaucoma Enhanced Referral Scheme (GERS), estimating both the false-positive (FP) and FN rates.

Method

Outcome data were collected for patients newly referred through GERS and assessed in ‘usual-care’ clinics to determine the FP rate (referred patients subsequently discharged at their first visit). For the FN rate, glaucoma suspects deemed not requiring referral following GERS assessment were invited to attend for a ‘reference standard’ examination including all elements of assessment recommended by National Institute for Health and Care Excellence (NICE) by a glaucoma specialist optometrist. A separate 33 cases comprising randomly selected referred and non-referred cases were reviewed independently by two glaucoma specialist consultant ophthalmologists to validate the reference standard assessment.

Results

1404 patients were evaluated in GERS during the study period; 651 (46.3%) were referred to the Hospital Eye Service (HES) and 753 (53.6%) were discharged. The FP rate in 307 assessable patients referred to the HES was 15.5%. This study reviewed 131 (17.4%) of those patients not referred to the HES through the GERS scheme; 117 (89.3%) were confirmed as not requiring hospital follow-up; 14 (10.7%) required follow-up, including 5 (3.8%) offered treatment. Only one patient (0.8%) in this sample met the GERS referral criteria and was not referred (true FN). There were no cases of missed glaucoma or non-glaucomatous pathology identified within our sample.

Conclusion

The Manchester GERS is an effective glaucoma filtering scheme with a low FP and FN rate.

Difference in intraocular pressure measurements between non-contact tonometry and Goldmann applanation tonometry and the role of central corneal thickness in affecting glaucoma referrals

BACKGROUND

Patients at glaucoma risk are commonly identified by optometrists and subsequently referred to glaucoma specialists. Optometrists mainly use non-contact tonometry (NCT) for intraocular pressure (IOP) measurement.

AIMS

To investigate the role of differences in IOP measurement between NCT and Goldmann applanation tonometry (GAT) and the effect of central corneal thickness (CCT) on these differences in optometrist referrals METHODS: Details of the initial clinical visit of patients referred with IOP > 21 mmHg in either eye as measured by NCT to a consultant glaucoma specialist were retrospectively reviewed. Demographic and referral data, IOP, CCT, and glaucoma diagnosis were obtained. The main outcome measure was the IOP measurement differences between NCT and GAT.

RESULTS

Of the 98 patients referred, only 23% had IOP > 21 mmHg when measured by GAT. NCT (Nidek NT400, Reichert Puff, Pulsair Easy Eye) measured the IOP greater than GAT by a mean of 5.8 mmHg (NCT 24.1 ± 3.5, GAT 18.3 ± 3.0). The effect of CCT on IOP measurement was less for GAT (R² 0.034, p = 0.067) than for NCT (R² 0.088, p = 0.003). The NCT/GAT IOP differences increased with increasing CCT (R² 0.166, p < 0.0001). The NCT/GAT differences decreased with patient age (R² 0.048, p = 0.03). Patients were classified as normal 67% (66/98), ocular hypertension 11% (11/98), glaucoma suspect 14% (14/98), and glaucoma 7% (7/98).

CONCLUSIONS

The difference in IOP measurement between NCT and GAT leads to a possible increase in glaucoma referrals, particularly in patients with thicker corneas. Repeat IOP using GAT and CCT measurement would help in triaging referrals.

Prospective study of glaucoma referrals across Europe: are we using resources wisely?

BACKGROUND

To investigate the outcomes of glaucoma referrals across different European countries.

METHODS

250 patients newly referred to tertiary referral glaucoma specialist practices in the UK, Hungary, Slovenia, Italy and Greece were prospectively enrolled (50 consecutive patients per centre). Referral accuracy and predictive value of referral criteria for an intervention or further monitoring (positive predictive value) were analysed.

RESULTS

Same-day discharges occurred in 43% (95% CI 39% to 75%) (12/28) of optometrist-initiated referrals (UK only), 37% (95% CI 30% to 45%) (59/158) of ophthalmologist-initiated referrals (all centres) and 54% (95% CI 40% to 68%) (26/48) of self-referrals (Hungary, Italy and Greece). The percentages from all referral sources were 46% (95% CI 32% to 60%) in the UK, 56% (95% CI 44% to 70%) in Hungary, 30% (95% CI 17% to 43%) in Slovenia, 22% (95% CI 11% to 34%) in Italy and 60% (95% CI 46% to 74%) in Greece (p<0.001). Overall, the referring criterion was confirmed in 54% (95% CI 45% to 63%) (64/119) for intraocular pressure (IOP) >21 mm Hg, 56% (95% CI 43% to 69%) (33/59) for a suspicious optic disc and 61% (95% CI 45% to 77%) (22/36) for a suspicious visual field, with large between-country differences (p<0.05 for all comparisons). Of all referrals, 32% (95% CI 26% to 37%) were initiated on the basis of IOP >21 mm Hg only. By combining the IOP criterion with any other referring criterion, the positive predictive value increased from 56% (95% CI 45% to 67%) to at least 89% (95% CI 68% to 100%). In the UK, a hypothetical IOP threshold of >26 mm Hg, as a requirement for IOP-only referrals, would reduce IOP-only referrals by 44%, while not missing any definite glaucoma cases.

CONCLUSION

The accuracy of referrals was poor in the UK and the other countries. Requiring a combination of criteria and raising the IOP threshold for IOP-only referrals are needed to cut waste in clinical care.

A Mixed-Methods Evaluation of a Community-Based Glaucoma Check Service in Hackney, London, UK

PURPOSE

To evaluate the uptake, feasibility and acceptability of a general practice-based optometrist-led glaucoma check service. The service targeted people of black Caribbean and black African descent aged 40-65 years, resident in Hackney, London, United Kingdom.

METHODS

The study used a mixed-method design, including analysis of service data, prospective audit of secondary care referrals patient survey, cost-consequence analysis, and interviews with staff involved in developing and implementing the service.

RESULTS

A total of 3040 patients were invited to undergo the free check; 595 (19.6%) booked an appointment and 461 (15.2%) attended. Overall, 31 patients (6.8%) were referred to secondary care, of whom 22 attended and were assessed for glaucoma. Four were diagnosed with glaucoma and eight with suspected glaucoma, i.e. 2.6% of patients who underwent the check. The cost per patient identified with suspected or confirmed glaucoma was £9,013. Staff who were interviewed suggested that patients who attended might be those who routinely attended optometrist appointments, however only 62.4% of survey respondents reported having had an eye examination in the previous two years, and 11.4% of women and 16.0% of men reported never having had an eye examination.

CONCLUSION

This study represents one possible configuration for a glaucoma case-finding service, and it contributes to a wider debate about whether screening, targeted or otherwise, should be offered in the UK. Our findings suggest that general practice is an acceptable setting and that such a service may reach some people not previously engaged with primary eye care services.

Factors influencing accuracy of referral and the likelihood of false positive referral by optometrists in Bradford, United Kingdom

AIMS

Levels of false positive referral to ophthalmology departments can be high. This study aimed to evaluate commonality between false positive referrals in order to find the factors which may influence referral accuracy.

METHODS

In 2007/08, a sample of 431 new Ophthalmology referrals from the catchment area of Bradford Royal Infirmary were retrospectively analysed.

RESULTS

The proportion of false positive referrals generated by optometrists decreases with experience at a rate of 6.2% per year since registration (p<0.0001). Community services which involved further investigation done by the optometrist before directly referring to the hospital were 2.7 times less likely to refer false positively than other referral formats (p=0.007). Male optometrists were about half as likely to generate a false positive referral than females (OR=0.51, p=0.008) and as multiple/corporate practices in the Bradford area employ less experienced and more female staff, independent practices generate about half the number of false positive referrals (OR=0.52, p=0.005).

CONCLUSIONS

Clinician experience has the greatest effect on referral accuracy although there is also a significant effect of gender with women tending to refer more false positives. This may be due to a different approach to patient care and possibly a greater sensitivity to litigation. The improved accuracy of community services (which often refer directly after further investigation) supports further growth of these schemes.

Australian optometric and ophthalmologic referral pathways for people with age-related macular degeneration, diabetic retinopathy and glaucoma

BACKGROUND

This study investigated the referral pathways offered to patients with age-related macular degeneration (AMD), diabetic retinopathy (DR) or glaucoma (GL) by ophthalmologists and optometrists.

METHODS

Australian ophthalmologists and optometrists were surveyed regarding referral decisions to other eye-care specialists (inter- or intra-professional), general medical practitioners (GPs), low vision rehabilitation (LVR) and support services. Thematic analysis and concept mapping were applied to highlight current and ideal referral pathways.

RESULTS

The survey was completed by 155 optometrists and 50 ophthalmologists and deemed representative of their respective professions in Australia. Not surprisingly, the vast majority of the participating optometrists (97 to 99 per cent) referred to ophthalmologists regardless of the underlying condition. Clear differences (Chi-square: p < 0.05) were observed in the referral patterns of optometrists and ophthalmologists to GPs and support services. General medical practitioner services were almost exclusively used for patients with DR, while AMD triggered a significantly higher referral rate to low vision rehabilitation and support services than the other two disorders.

CONCLUSION

While ophthalmologists predominantly referred patients with AMD, DR or GL to low vision rehabilitation services, optometrists' referrals were highly skewed toward ophthalmology. Referrals to other supporting services by the two groups were not greatly used. The perceived referral pathways by the two eye-care professionals suggested a unidirectional route, potentially highlighting the need for a more collaborative approach that facilitates optimal use of eye health care and allied services.

Socioeconomic status as a risk factor for late presentation of glaucoma in Canada

OBJECTIVE

To evaluate the effect of socioeconomic status on late presentation of glaucoma.

DESIGN

Prospective, multicentre, cross-sectional study.

PARTICIPANTS

Newly diagnosed open-angle glaucoma.

METHODS

Eligible subjects with newly diagnosed open-angle glaucoma underwent a comprehensive ocular examination and were classified as mild, moderate, or advanced according to the Canadian Ophthalmological Society glaucoma guidelines. Socioeconomic status was estimated by linking the subjects' postal code to the median household income in the 2006 Canadian population census at the level of dissemination areas. Five equal income groups ranging from the lowest to the highest income quintile were considered and compared regarding the frequency and proportion of moderate or advanced glaucoma.

RESULTS

A total of 290 subjects were included in the analysis; 151 (52.1%) had mild, 79 (26.9%) moderate, and 60 (21.0%) advanced disease at initial diagnosis. Patients with newly diagnosed glaucoma were less likely to come from the poorest neighborhood areas (16.21%) when compared with an expected one fifth (20%) of patients presented in each of the 5 social economic groups (P = 0.56). Compared with people from the poorest neighborhood areas, people from the richest neighborhood areas had a marginally lower risk for having moderate or advanced glaucoma at first presentation (prevalence ratio 0.66, 95% confidence interval: 0.43-1.02, P = 0.06). This association was stronger among those ≥65 years old (P = 0.006).

CONCLUSIONS

To the best of our knowledge, this is the first study in Canada to provide evidence that socioeconomic deprivation is associated with greater severity of glaucoma at presentation, specifically for those ≥65 years old. Consideration should be given to targeting poor neighborhood areas for glaucoma education, screening, or both.

The willingness of patients presenting with advanced glaucoma to participate in a trial comparing primary medical vs primary surgical treatment

AIM

The aim of this study is to examine the attitudes of patients, who presented with advanced glaucoma in at least one eye, to participation in a randomised prospective trial comparing primary medical treatment with primary surgical treatment for advanced glaucoma.

METHODS

Patients who had presented with advanced glaucoma (>15 dB loss mean deviation on Humphrey visual field testing) in at least one eye were asked to participate. Five focus groups comprising of 4-8 patients and consisting of 29 patients in total were undertaken. The group interviews were conducted by two experienced qualitative researchers, an ophthalmic clinician was present to clarify technical issues. The focus group discussions were taped and transcribed in full, and analysed through a process of familiarisation, open (inductive) coding, theme generation, theme refinement, and thematic mapping.

RESULTS

Three overarching themes were identified: (1) the extent of patients' knowledge, (2) anxieties about surgery, and (3) concerns about compromised care due to trial involvement; these themes were further classified into eight sub-themes.

CONCLUSIONS

Patients' willingness to participate in randomised clinical studies is significantly connected to their level of comprehension and insight about the medical condition, its treatment, and the research process; misunderstandings about any of these aspects may act as a significant barrier to trial recruitment. Recruitment rates for future randomised trials may be enhanced by ensuring that patients have full and accurate information about the treatment alternatives, and that uncertainty exists for best patient outcomes between treatment options, and reassuring potential participants that the research process, in particular randomisation, will not compromise clinical care.

Assessment of referrals to the hospital eye service by optometrists and GPs in Bradford and Airedale

PURPOSE

To investigate the content of referrals to a hospital eye department and describe differences between referring clinician (optometrist or GP) and referral formats.

METHODS

A random sample of 433 new referrals to Bradford Royal Infirmary hospital eye service (HES) during 2007 and 2008 were retrospectively analysed.

RESULTS

Three hundred and eleven referrals (72%) were from optometric practice and 122 (28%) from general practice. Optometric referrals were mainly for cataract and posterior capsular opacification (27%), glaucoma or suspect glaucoma (20%) and diabetic retinopathy (10%).

CONCLUSIONS

The proportion of referrals to the hospital eye service from optometrists appears to be increasing (1988: 39%, 1999: 48%, present study 72%). GPs mainly refer patients with anterior segment disorders, particularly lid lesions, based on direct observation and symptoms. Optometrists refer patients with a wide range of ocular diseases and include fundus observations and visual acuity measurements in their referrals. There is a need to inform optometrists of what content is required in a referral to the HES from GOS sight tests, at least for the common referral conditions such as age-related cataract and suspect open-angle glaucoma. Referral forms specifically designed for these commonly referred conditions are likely to improve referral quality.

Optometrists referrals for glaucoma assessment: a prospective survey of clinical data and outcomes

AIM

The aim of this study is to determine the outcomes following referral for glaucoma from routine optometric practice and the positive predictive value (PPV).

METHODS

A prospective study of 441 referrals for glaucoma in the Portsmouth area was performed over 6 months. A positive outcome was defined when the patient had the diagnosis of glaucoma made or if there was a high index of suspicion of glaucoma requiring follow-up. The PPV was determined from positive outcome number/referral number.

RESULTS

The overall PPV was 0.37 (95% confidence interval 0.33-0.42). Open-angle glaucoma (OAG) was confirmed in 33 (7%) patients. A diagnosis of ocular hypertension was made in 49 (11%) patients and glaucoma suspect in 92 (21%) referrals. Two-thirds of optometrists recorded all 3 assessments: fields, intraocular pressure (IOP) and disc appearance, a figure representing 293 referrals (PPV 0.37). However the greatest referral accuracy was seen when only discs and IOPs were recorded (PPV 0.47). When all three tests were given as reasons for suspicion for glaucoma, the PPV was 0.71. The number of patients diagnosed with OAG from Portsea Island during the study period was 7, whereas the expected number of diagnosed patients was 29.

CONCLUSION

Wider use of perimetry by optometrists and increased reporting of all three tests has not led to an increase in PPV. There remain a considerable number of undiagnosed patients with glaucoma in the population.

The quality of optometrists' referral letters for glaucoma

PURPOSE

The purpose of the study was to evaluate the quality of content of optometrist-initiated glaucoma referral letters arriving at the appointment booking centre at Moorfields Eye Hospital (MEH).

METHODS

The minimum standard of information required for an ophthalmologist to determine the appropriateness and urgency of glaucoma suspect referral was determined, and criteria for three standards of referral letter formulated: 'Ideal', 'Acceptable' and 'Fail'. These standards were applied to a prospective review of all optometrist-derived referrals for glaucoma or suspected glaucoma cases arriving in the MEH booking centre over a 4-month period. The contents of each letter were scrutinised and classified based on the criteria within each standard.

RESULTS

Forty-nine per cent of referral letters were found to be of 'acceptable' quality, 7%'ideal' quality and the remainder classed as "fail". The main reason for failure was an omission of non-clinical information, including patient and/or referring practice details, although 26% of letters failed to include an optic disc evaluation and 6% failed to provide intra-ocular pressure measurements. Two-thirds of 'acceptable' letters did not reach the 'ideal' standard due to a lack of discussion of risk factors, visual field analysis or recommendations for referral speed.

DISCUSSION

The information gleaned from this prospective study indicates a need to improve the quality of optometrists' glaucoma referral letters, particularly with respect to completion of all the items set out on the General Ophthalmic Services (GOS) 18 referral form.

Referrals to ophthalmology: optometric and general practice comparison

PURPOSE

To assess referrals from primary care practitioners to an ophthalmological practice in order to determine whether any differences exist between the two primary care groups in the types of conditions referred, and in concurrence between reasons for referral and ophthalmological diagnosis.

METHODS

This study investigated patient referrals from general practitioners and optometrists to an ophthalmologist's practice in Belfast, over a period of 3 months from January 2007 to the end of March 2007. Anonymised data were divided into two groups depending on the referring practitioner. Within the two groups, patient numbers were sub-divided into 15 categories covering the range of diagnoses made. Preliminary diagnoses or reasons for referral were compared with the definitive diagnoses made by the ophthalmologist.

RESULTS

Optometrists contributed the greatest number of referrals (323) with 243 patients referred by general practitioners. Cataract was the most common condition referred by optometrists, and the second most common condition referred by general practitioners: agreement with ophthalmological diagnosis was high for both groups of primary care practitioners. Concurrence of referral reason with ophthalmological diagnosis for glaucoma was lower for general practitioners (56%) than for optometrists (76%), but optometrists referred more false positive patients for glaucoma than did general practitioners. The opposite was true for lid/tear duct/conjunctival conditions, the most common basis for referral by general practitioners.

CONCLUSIONS

The differences between the two primary care practitioner groups may reflect variations in training, skills and practice. Further investigation of the particular strengths of both groups, and how they can be optimised to promote effective shared care, is required.

An analysis of patients discharged from a hospital-based glaucoma case-finding clinic over a 3-year period

PURPOSE

To analyse the false positive referrals by community optometrists to a glaucoma case-finding clinic over a 3-year period.

METHODS

A retrospective study was undertaken of the 531 patients who were referred by community optometrists and discharged after their first visit to the glaucoma case-finding clinic at the Oxford Eye Hospital between 2003 and 2005. The number of patients who were referred on the basis of one, two or three abnormal parameters was determined. The specific reason why the presumed abnormal parameter was considered normal by a glaucoma specialist was determined from the patients' records.

RESULTS

The referral was based on only one presumed abnormal parameter in 65.5-74.3% of patients (minimum-maximum percentage per year, 2003-2005). Physiological cupping was present in 21.5-29.5%, asymmetrical cupping because of asymmetrical disc size in 6.4-8.2% and asymmetrical cupping in the presence of similar disc size in 1.9-5.1%. An intraocular pressure (IOP) within the normal range was measured in 17.6-20.8% and an IOP between 22 and 25 mmHg in association with a central corneal thickness of >588 microm was found in a further 11.5-15.4%. In 11.5-16.1% of patients who were referred because of an abnormal visual field, no field defect was found when the test was repeated. A cause other than glaucoma was responsible for an abnormal visual field defect in 1.2-6%.

CONCLUSION

This study identifies the factors responsible for false positive referrals to a hospital-based glaucoma case-finding clinic. By considering these factors and by combining test data, the number of unnecessary referrals could be reduced in the future.

Outcomes of referrals by community optometrists to a hospital glaucoma service

AIM

To determine the outcomes resulting from optometric referrals to a specialist glaucoma screening clinic over a 10 year period.

METHODS

Details of the initial clinical assessment of all new patients referred to the adult glaucoma screening clinic at Oxford Eye Hospital were collected prospectively from July 1994 to June 2004.

RESULTS

Optometrists working in community practice initiated 2505 referrals. Of these, glaucoma was confirmed in 510 patients (20.4%), including 160 with normal intraocular pressure (IOP). A diagnosis of ocular hypertension was made in 747 patients (29.8% of referrals) and 125 (5.0%) were categorised as glaucoma suspects. There was no evidence of a diagnostic trend over the period of data collection. Treatment to lower IOP was commenced in 458 patients (18.3%). Nearly half of those referred, 1148 (45.8%), were discharged from ophthalmological review at the first visit.

CONCLUSION

In this survey, the largest of its nature, only one in five subjects had glaucoma and nearly half were discharged from hospital ophthalmological review. The findings provide a baseline against which the effectiveness of any future system of glaucoma detection in the United Kingdom can be compared.

Glaucoma detection in the community: does ongoing training of optometrists have a lasting effect?

PURPOSE

To establish whether the effect of improved glaucoma detection in the community suggested by an intervention study is maintained when intervention is extended to include all optometrists in the area.

METHODS

Optometrists' in the Ealing, Hammersmith, and Hounslow area were invited to ongoing training sessions following completion of an intervention study. The number of optometrist initiated referrals to Ealing Hospital Eye Clinic (EHEC) for suspect glaucoma was assessed over a 12-month period. The positive predictive value (PPV) of those referrals was calculated and a historical comparison made with the results of the original study.

RESULTS

A total of 376 new referrals for suspected glaucoma were assessed at EHEC during the 12-month period of data collection. This represents an increase in the number of referrals of 58% compared with an equivalent 12-month period during the initial intervention trial (376 vs. 238). The PPV was maintained at 0.45 (95% CI 0.41-0.51).

CONCLUSION

The rising number of new referrals for glaucoma together with maintenance of the PPV suggests an impact on the number of new cases of glaucoma detected in the community. The increase in referral numbers was limited to glaucoma when compared with new referrals for cataract. This implies a targeted effect of the intervention in terms of glaucoma detection. We believe the next step is to perform the study in an alternative location to see if the effect is repeatable elsewhere. If proven to be the case, there is a coherent argument for widespread adoption of this strategy to improve glaucoma case finding.

Evaluation of risk factors for advanced glaucoma in Ghanaian patients

PURPOSE

This study was to determine factors associated with individuals presenting late with advanced glaucomatous optic nerve damage.

METHODS

A case-control study recruiting 123 patients with early features of primary open angle glaucoma (control) and 93 patients with advanced glaucoma (cases) was carried out for risk-factor analysis. Exposures of interest included those already established as major risk factors for glaucoma. These were initial intraocular pressure (IOP), age, and family history. In addition, occupation, ethnic origin, history of diagnosis of diabetes mellitus, hypertension, sickle cell disease, and previous eye examination were of interest.

RESULTS

Univariate analysis showed that initial IOP>31 mmHg, age of > 60 years, absence of family history of glaucoma, occupational grouping, ethnicity, and male sex were associated with advanced glaucoma at presentation. Adjusted odds ratio or by multiple logistic regression model showed that initial IOP>31 mmHg in a patient was more likely to present with advanced glaucoma (OR 2.66, 95% confidence interval (CI) 1.45, 4.91; P-value 0.0017) than lower pressures. Patients aged 60-69 years (OR 2.53, 95% CI 1.01, 6.31; P-value 0.0473) and 70-90 years (OR 5.16, 95% CI 1.97, 13.51; P-value 0.0008) were more likely to present with advanced glaucoma than younger ones

CONCLUSIONS

Subjects with initial IOP>31 mmHg were nearly three times more likely to present with advanced glaucoma than those with IOP<32 mmHg. Subjects over the age of 60 years were more than two times likely to present with advanced glaucoma than younger subjects.

Ten years of glaucoma blindness in Fife 1990-99 and the implications for ophthalmology, optometry and rehabilitation services*

The aim of this study was to determine the characteristics of the patients in Fife who were registered as blind with a main diagnosis of glaucoma between 1990 and 1999. The case notes of 87 people were studied. The average age at registration was 78 years (S.D. = 14). By the time of first referral to hospital, more than half were already aware of visual loss. Forty-five per cent of referrals had no optometry input. Compliance with treatment was poor in at least 26% of patients. Only 44% had glaucoma surgery. There were significant findings with regard to mental health, particularly dementia, which was eventually present in 24%. At least one-third of patients had a hearing impairment. One-third of those registered as blind could have been registered earlier. However, staff from the local provider of rehabilitation and social work services for the blind were shown to have provided prompt and helpful support to 95% of those registered. Consideration should be given to the way in which elderly patients with advanced glaucoma are managed, with awareness of mental health and hearing problems and emphasis on early referral to rehabilitation services.

Glaucoma case finding: a cluster-randomised intervention trial

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 = 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.

Sensitivity and specificity of two glaucoma case-finding strategies for optometrists

Current best practice for primary open-angle glaucoma case-finding comprises history-taking, disc examination, intraocular pressure measurement and suprathreshold visual field analysis (SVFA). An alternative case-finding technique was formulated replacing SVFA with computerised quantitative disc assessment, using the Heidelberg retinal tomograph II (HRT II). Each approach was adopted by four optometrists who screened 29 POAG and 37 normal patients. Average sensitivities and specificities were similar in the two groups [sensitivity 71% (SVFA) vs 69% (HRT II); specificity 94% both groups]. Our inclusion of pre-perimetric glaucoma cases limited the sensitivity of the optometrists in this study. There was evidence to suggest that the optometrists tended to miss early changes at the optic disc such as disc haemorrhage, nerve fibre layer defects and subtle neuroretinal thinning.

Blindness in patients with treated open-angle glaucoma

PURPOSE

To investigate blindness in patients with treated open-angle glaucoma (OAG) and risk factors for blindness.

DESIGN

Retrospective observational case series.

PARTICIPANTS

One hundred eighty-six patients seen between April and November 2000 at the University of Washington Medical Center Eye Clinic, diagnosed in 1975 or later, and treated for at least 2 years for OAG.

METHODS

Chart review with evaluation of visual acuity and visual field. Kaplan-Meier survival analysis was used to estimate the risk of blindness in one and both eyes. Variables considered to be possible risk factors for blindness were evaluated using chi-square test, t test, and Cox proportional hazards regression analysis.

MAIN OUTCOME MEASURES

Blindness, defined as visual acuity of 20/200 or worse, and/or continuous constriction of the visual field to 20 degrees or less in all four quadrants with a size III4e Goldmann stimulus or the equivalent on automated perimetry, allowing a higher threshold level on one point in one quadrant on automated perimetry.

RESULTS

The mean duration of disease was 10.2 +/- 4.9 years. Twelve patients were blind in at least one eye from OAG at diagnosis. Nineteen other patients became blind in at least one eye from OAG, and three patients became bilaterally blind from OAG. The Kaplan-Meier estimate for blindness at 15 years in one eye was 14.6%, and in both eyes was 6.4%. Noncompliance with the treatment regimen (P = 0.016) and worse initial visual field loss (P < 0.0001) were significantly associated with development of blindness. Nonwhite race was associated with blindness (P = 0.014) when all blindness, including that found at diagnosis, was considered in the analysis.

CONCLUSIONS

Bilateral blindness from chronic OAG was uncommon in this population of treated patients diagnosed in 1975 or later. Of patients with a blind eye, 39% were blind at diagnosis, and worse visual field loss at diagnosis and noncompliance were associated with development of blindness.

The projected increase in glaucoma due to an ageing population

The number of cases of primary open angle glaucoma (POAG) in England and Wales is estimated to increase by a third over the 20 years to 2021, and then continue upwards at a similar pace to 2031. The estimates are based on official population projections, organised by 5-year age groups, together with an age-specific prevalence curve for POAG derived from the results of 11 epidemiological prevalence surveys. To cope with additional pressures, a thorough reappraisal of the present system for detection, referral, diagnosis, treatment and monitoring of the disease is likely to be required.

Does a family history of glaucoma affect disease severity at the time of diagnosis?

PURPOSE

Progressive glaucomatous optic neuropathy is an asymptomatic process with an insidious onset. Patients who are aware of glaucomatous signs and who suspect that they may have the disease may present earlier. If a person has glaucoma, this may alert his or her other family members to seek assessment and thereby permit earlier diagnosis. The authors sought to determine whether glaucoma patients with a family history of the disease were younger and showed less evidence of glaucomatous optic neuropathy at diagnosis than glaucoma patients without a family history of the disease.

PATIENTS AND METHODS

Family history of glaucoma, age at diagnosis, and visual field mean defect within 2 years after diagnosis were recorded in 292 patients with primary open-angle glaucoma. Results were analyzed to compare visual field loss with age and family history.

RESULTS

At diagnosis, patients with a family history of glaucoma were younger than those without such a history (mean +/- SD, 58 +/- 12.7 years versus 63 +/- 10.8 years; = 3.68, P<0.001). Patients who were younger than 50 years at the time of diagnosis and had a positive family history were significantly less likely to have a worse visual field than those with a negative family history (OR = 0.3; 95% CI, 0.1-0.6; P<0.001), whereas those aged 50 years or older showed no such correlation (OR = 0.9; 95% CI, 0.7-1.3; P = 0.6).

CONCLUSION

A family history of glaucoma was associated with a better visual field at diagnosis in patients younger than 50 years, but not in patients 50 years or older.

Factors affecting awareness and knowledge of glaucoma among patients presenting to an urban emergency department

BACKGROUND

Until advanced, glaucoma is asymptomatic. For early diagnosis to occur, patients may need to be aware of it and seek assessment regularly. People who have risk factors for glaucoma may have a greater awareness of the disease.

METHODS

Patients presenting to an urban hospital emergency department were surveyed with a brief questionnaire to assess their knowledge of glaucoma. Data was collected about their gender, age, family history of glaucoma and presence of systemic hypertension, diabetes, Raynaud's phenomenon, migraines and myopia.

RESULTS

Women (Odds ratio 2.3; 95% CI 1.4-3.7; P < 0.01), people who were 40 years or older (Odds ratio 2.2; 95% CI 1.1-4.4; P < 0.05) and those who were aware of a family history of glaucoma (Odds ratio 15.7; CI 5.5-45.3; P < 0.01) knew significantly more about the disease than others. People with other risk factors did not demonstrate significantly greater knowledge despite 89% of all participants having had a previous eye examination.

CONCLUSION

This information may be useful to predict which patients may know about glaucoma when they present for an eye examination and who should be targeted in public health campaigns.

Do locally agreed guidelines for optometrists concerning the referral of glaucoma suspects influence referral practice?

PURPOSE

To assess whether the issuing of local guidelines for glaucoma detection including a protocol for the referral of suspects can improve the quality and accuracy of referrals from optometrists.

METHODS

Universally agreed guidelines, which included a protocol for referring glaucoma suspects, were circulated to all optometrists in the catchment area of a major teaching hospital ophthalmic unit. Data on 207 new patients referred to one glaucoma clinic were collected from GOS18 forms and hospital records covering two 12 month periods spanning the guideline dissemination. Referral accuracy was calculated and the reasons for protocol violations and referral of normal individuals were determined. Where possible, data were compared with a similar study relating to referrals made to the same clinic in 1988 and 1993.

RESULTS

The mean (SD) intraocular pressure (IOP) at which optometrists referred patients was 22.5 (6.6) in 1997 and 21.9 mmHg (6.6) in 1998/9, both significantly less than in 1988. A statistically significant upward trend with time was found in the number of patients referred with an assessment of cup/disc ratio and in those with details of a visual field assessment. The overall 'true positive diagnosis' was 40% (42/105) in 1997 and 32.3% (33/102) in 1998/9 after the guidelines (p = 0.32), both of which were significantly lower than the 1988 rate of 56% (34/75) (p = 0.03 and 0.003). Fifty per cent of false positive referrals in both 1997 and 1998/9 were associated with an assessment by the optometrist of the optic disc(s) that was at variance with the ophthalmologist's. False positive visual fields were associated with 22% and 35% of non-true positive referrals in 1997 and 1998/9. Protocol violations were observed in 48% of referrals after the guidelines had been disseminated. When the referral was both a false positive and the guideline protocol was not followed, 88% of violations were associated with IOP measurement in 1997 and 73% in 1998/9. The equivalent figures for visual field violations were 70% in 1997 and 76% in 1998/9. Normal individuals referred as suspects were significantly (p = 0.001) less likely to be referred on IOP grounds if their optometrist followed the referral protocol.

CONCLUSION

Local dissemination of glaucoma screening guidelines with a protocol for referral did not appear to improve the diagnostic accuracy of optometrists in our area. Optometrists who follow the guidelines refer fewer normal individuals on IOP grounds, but false positive visual fields and optic disc interpretation difficulties remain a factor in such referrals. Additional strategies will be necessary to improve the quality and accuracy of referrals for suspect glaucoma by optometrists.

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

PURPOSE

Visual field testing is increasingly being performed by optometrists in order to improve glaucoma detection. The aim of this study was to assess the positive predictive value (PPV) of visual field testing as currently practised by optometrists.

METHODS

A retrospective study was performed of referrals for suspected glaucoma to an ophthalmology department during a 3 month period. The PPV for glaucoma was determined according to the reason for referral.

RESULTS

There were 86 referrals for suspected glaucoma. Isolated field loss accounted for 12% of these referrals but no cases of glaucoma detection. These subjects were either false positive referrals or had field defects of nonglaucomatous aetiology (tilted optic disc and porencephalic cyst). The PPV for glaucoma among referrals with isolated field loss was significantly less than that among referrals with field loss in association with corroborative abnormalities (0 vs. 60%, p = 0.005). No such difference was found for referrals with raised intraocular pressure (43% vs. 57%, p = 0.38) or suspicious discs (25% vs. 53%, p = 0.60).

CONCLUSIONS

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.

The changing pattern of glaucoma referrals by optometrists

PURPOSE

To identify any change in optometric referral patterns for suspect glaucoma over a 5 year period.

METHOD

A retrospective analysis was carried out of referrals for suspect glaucoma to a hospital glaucoma clinic from 1988 and 1993.

RESULTS

There was a significant decrease in the positive referral rate with time from 56% in 1988 to 37% in 1993 (p = 0.02). Intraocular pressures (IOPs) of all patients prior to referral and at presentation to the glaucoma clinic were significantly higher in 1988 (25.1 and 25.6 mmHg respectively) than in 1993 (22.4 and 23.0 mmHg respectively, p < 0.0005). However, the presenting IOPs of eyes with glaucoma were similar in the cohorts (27.5 vs 26.4 mmHg, p = 0.33). Prior to referral, optometrists performed visual fields on 28% of patients in 1988 and on 48% in 1993 (p 0.01), giving an estimate of the cup/disc ratio in 15% of patients in 1988 and 41% in 1993 (p = 0.0004).

CONCLUSIONS

The increased false positive referral rate appears to be associated with the increasing use of visual field analysers by optometrists and a willingness to refer at lower IOPs. Increased false positive referrals result in increased waiting times for hospital assessment.

Positive predictive value of optometrist-initiated referrals for glaucoma

A study was conducted at the Moorfields Community Eye Clinic at Ealing Hospital to determine the positive predictive value (ppv) of optometric referrals for suspected glaucoma. The information reported in the referrals and the reasons given for referral were also assessed and evaluated in relation to the ppv. Information was gathered through prospective analysis of patient clinic notes. Ninety patients were referred over a six-month period of which 87 fulfilled the inclusion criteria. The optometrist referral letters for 79 of these patients were supplied by the GP. Results indicate a ppv of 0.43. The reason for referral in the majority of cases (48%) was raised IOP alone. However the most frequently reported mode of practice was a combination of disc and IOP assessment (57%). In line with other research our study demonstrates that referral accuracy improves as the number of suspicious findings increases. In addition those referrals reporting all three tests (IOP measurement, optic disc assessment and perimetry) are shown to have the highest ppv.

Retrospective analysis of risk factors for late presentation of chronic glaucoma

BACKGROUND

Why some individuals present to the ophthalmologist in the early stages of chronic glaucoma but others present with very advanced visual field loss is a question which has received little attention. This study is an attempt to identify some basic characteristics of people who present with late glaucoma.

METHODS

A retrospective case-control study by medical record review was employed. 100 cases and 100 controls were identified from the notes of patients presenting to Moorfields Eye Hospital glaucoma service between July 1993 and July 1995. Cases were defined as new patients presenting with absolute field loss within five degrees of fixation and a cup to disc ratio of greater than 0.8 in one or both eyes. Controls were new patients with no absolute field loss within 20 degrees in either eye, but otherwise typical glaucomatous field loss and a cup to disc ratio of greater than 0.5 or a difference of 0.2 or more between the discs.

RESULTS

The ethnic origin, sex, referral source, presenting IOP, and age of the subjects studied were independently associated with late presentation. An African Caribbean patient is estimated to be four and a half times more likely to attend with advanced field loss than a white patient of similar age, sex, IOP, and referral source (adj OR: 4.55, 95% CI [1.57, 13.18]). A female patient is estimated to be one third (0.34, [0.15, 0.74]) as likely to attend late than a male patient of the similar age, IOP, ethnic origin, and referral source. A patient referred via any source other than an optometrist with the correct diagnosis is estimated to be greater than four times (4.32 [1.89, 9.88]) more likely to be a late attender than a patient of the same sex, ethnicity, and similar age but referred with a diagnosis of glaucoma. There was a trend of increasing odds of late presentation with increasing age (adj OR per 10 years, baseline 40-49 years 1.68 [1.22, 2.20]). A patient whose presenting IOP is 21-25 mm Hg is estimated to be a quarter (0.24, [0.09, 0.64]) as likely to attend with advanced field loss than a patient of the same ethnic origin, sex, age, referral source, but with presenting IOP of greater than 31 mm Hg.

CONCLUSIONS

These data strongly suggest that certain subgroups of patients with glaucoma are likely to be at greater risk of presenting with advanced and irremediable field loss.

The cost-effectiveness of various modes of screening for primary open angle glaucoma

Various modes of screening for glaucoma were defined in terms of different combinations of the three main tests (ophthalmoscopy (O), tonometry (T), and perimetry (P)), together with associated referral criteria. The number of referrals and true positives generated by each mode was estimated for a model population, which was distributed with respect to age, intraocular pressure (IOP), optic disc condition, visual field defects, family history of glaucoma, and myopic status, as indicated by epidemiological studies. The costs of primary examination, and also of the secondary examination of referrals, were estimated for each mode, thus enabling the total cost per true positive to be calculated (in Pound sterling at 1995 UK prices, subsequently converted to US dollars at Pound 1.00 = $1.55.) The modes using O and T routinely, with P either routinely or selectively on all glaucoma high-risk groups, were found to provide the best balance between sensitivity (> or = 80%) and cost per true positive. The latter was around $850 when the cost of ophthalmoscopy could be shared as part of a general eye examination. The calculations assumed a 0.6% prevalence of previously undetected glaucomas in the community: with higher prevalences, costs per true positive would be lower. Screening the 40-59 years age group was found to be about as economic as for older people, when life expectancy was taken into account. It was concluded that glaucoma screening of people over age 40 years could be justifiable, provided that it is worth more than about $850 to detect a new case. Whilst based on UK values, the analysis could be applied to different primary health care settings in other countries.