Screening for glaucoma in the community by non-ophthalmologically trained staff using semi automated equipment

Abstract

SummaryEighty-nine and a half per cent of the population of a general practice over the age of 49 years were screened for glaucoma and high risk ocular hypertension requiring treatment. Screening took place using semi-automated intraocular pressure and visual field equipment operated by non-ophthalmologicaUy trained staff. An experi enced ophthalmologist examined aU patients in a single blind manner to reduce false negatives to a minimum. Patients suspected of requiring treatment on the grounds of raised intraocular pressure, abnormal visual fields or suspicious optic discs were subsequently examined in a hospital clinic. Treatment criteria, as commonly prac ticed, were carefully defined and the sensitivities and specificities of the methods of screening used were calculated. One and three tenths per cent of the practice popula tion were known to be receiving treatment prior to the study and a further 1.4%were found to require treatment after screening.The sensitivity and specificity of the non-contact tonometer were 91.7% and 95.6% respectively with a predictive power of 22.5% for a positive result. The mean time taken to perform the test in both eyes was two minutes. Seventy per cent of the patients with pressures over 22 mmHg in both eyes on screening were found to require treatment. The routine use of the field screener did not increase either the sensitivity or specificity of the screening process but its use in cases with raised intraocular pressure is advised to indicate the degree of urgency of the referral.An algorithm based on the results of the study is suggested when planning the use of semi-automated equipment to screen for ocular disease related to raised intra ocular pressure.Chronic Simple Glaucoma (CSG) is a com mon disease of middle age and the elderly, prevalence rising from 0.5-1 % of the popula tion over the age of 401,2 to 6.6% over 75.3 It is responsible for up to 16.8% of registrable blindness in the population of the United Kingdom aged over 65 years.4CSG is characterised by a triad of physical signs: raised intraocular pressure (lOP),

The clinical effectiveness and cost-effectiveness of screening for open angle glaucoma: a systematic review and economic evaluation

“…178 Twenty-six studies gave details of the gender of their participants, 51% of whom were women. 21 164,165 No studies of GDx VCC, OCT, RTA, SWAP, MDP or Tonopen met the inclusion criteria in terms of reporting of test accuracy outcomes.…”

“…21,22,99,100,106,107,109,110,112,115,132,154,157,159,163,164,168,169 Out of a total of 58,708 eligible people, 44,653 (76.1%) attended for screening (median 82.8%, range 28.3-99.5%) ( Table 17). Fifteen of these studies are included in the screening and diagnostic accuracy review.…”

“…Seven studies enrolling 7279 people reported the test accuracy of ophthalmoscopy, including four population-based studies, 115,163,164,168 two cohort studies 172,177 and one case-control study. these studies.…”

“…The earliest study took place in 1963 21 and the latest in 2003/04, 156,176 while 21 studies gave no indication of the period in which they were carried out. Thirteen studies took place in the USA, 22,158,159,162,166,168,170,172,175,181,[187][188][189] nine in the UK, 21,164,176,177,180,182,186,190,191 four in Australia, 115,157,163,173 two each in Italy, 106,174 The Netherlands, 169,183 Spain 99,179 and Sweden, 100,171 one each in Belgium, 155 Canada, 156 Greece, 112 India 161 and Norway, 154 and one in Canada and Finland. 178 Twenty-six studies gave details of the gender of their participants, 51% of whom were women.…”

“…There were 20 population-based studies representative of a screening setting. 21,72,99,100,106,112,115,[154][155][156][157][158][159][160][161][162][163][164][165][166][167][168][169][170] Twenty studies were representative of a glaucoma suspect population referred from primary care, of which eight were cohort studies 22,171-177 and 12 were case-control studies. [178][179][180][181][182][183][184][185][186][187][188][189][190][191] …”