Glaucoma screening by optometrists

Studies undertaken in the United Kingdom have indicated that optometrists are responsible for the initial detection of most cases of glaucoma and are much more efficient at screening for glaucoma than general practitioners. In this study we were interested in determining how optometrists screened for glaucoma. This was undertaken by sending a survey to 50 registered optometrists practising in the Brisbane area to derive information on facilities available for glaucoma screening, modes of testing and on criteria adopted for referral of patients. The response rate was 60 per cent to the first section of the survey and 42 per cent to the second, and more detailed section of the survey. The results demonstrated that all respondents have facilities for screening by tonometry and ophthalmoscopy, with 73 per cent also having facilities for visual field testing. All responding optometrists undertake optic disc examination on all patients. Intraocular pressure (IOP) was measured on all patients aged 40 years and over, with selective testing of those patients less than 40 years of age, depending on disc appearance, visual fields and family ocular history (FOH) of glaucoma. Visual fields were tested selectively, depending on disc appearance, IOP, age and FOH of glaucoma. Seventy-six per cent of respondents would refer for IOP>24 mm Hg if optic discs were normal, whereas if optic discs were suspicious, 90 per cent would refer for an IOP>21 mm Hg. All indicated that they would test visual fields of patients with IOP>25 mm Hg, irrespective of disc appearance or FOH of glaucoma. The majority of optometrists would refer for characteristic field losses, for optic disc changes including a C/D ratio >0.6 or a C/D asymmetry of 0.2 or 0.3. The results indicate that optometrists are aware of the risk factors and subtle changes associated with glaucoma and would detect most patients with glaucoma. Accepted for publication: 30 August 1993 (Clin Exp Optom 1993; 76:6:199–207)     

XPERT非接触性眼压计的临床应用

对ＸＰＥＲＴ非接触性眼压计进行准确性研究,为该眼压计在临床和青光眼筛选的应用提供可靠依据。方法：应用ＸＰＥＲＴ非接触性眼压计和Ｇｏｌｄｍａｎｎ压平眼压计测定了２９３眼（１５０例）的眼压,并对其眼压值进行统计学分析。结果：ＸＰＥＲＴ非接触性眼压计和Ｇｏｌｄｍａｎｎ压平眼压计测量值呈密切相关（ｒ＝０．９７０２,Ｐ＝０．００００）。两者测定的均数差＝０．１５５３（Ｐ＞０．０５）。以Ｇｏｌｄｍａｎｎ压平眼压计测定为标准,ＸＰＥＲＴ非接触性眼压计测定值的波动范围在±０．１３３ｋＰａ（１ｍｍＨｇ）内占５７．７％,在±０．４ｋＰａ（３ｍｍＨｇ）内的占８５％,在±０．６５５ｋＰａ（５ｍｍＨｇ）内的占９６．６％。结论：经研究显示ＸＰＥＲＴ非接触性眼压计和Ｇｏｌｄｍａｎｎ压平眼压计的测量值一致性和相关性较好,可以应用于临床和人群青光眼检查快速筛检眼压升高者。     

Brisbane GPs' perceptions of screening for primary open-angle glaucoma

Background: Primary open-angle glaucoma (POAG) is one of the three leading causes of blindness in Australia, often causing considerable visual field loss before the patient becomes symptomatic. Recent years have seen a quickening of public health interest in primary open-angle glaucoma. Our study evaluates the attitudes and skills of Brisbane GPs with regard to screening for POAG. Objectives: To evaluate general practitioners' current use of possible screening modalities for POAG. To evaluate general practitioners' attitudes to screening for POAG. To evaluate general practitioner's levels of satisfaction with their knowledge and skills in the diagnosis of common ophthalmological conditions. Method: A questionnaire was distributed to 130 randomly selected GPs in the Brisbane metropolitan area. Response rate was 94%. Results: Tonometry and funduscopy were infrequently used in Brisbane general practice. Only 15% of the sample were satisfied with their current knowledge and skills concerning the detection of POAG. 88% felt that patients >50 years should be screened for POAG and nominated a variety of sources — 75% advocating ophthalmology screeners, 65% GP screeners, and 41% optometrist screeners. Ninety-nine per cent believed ophthalmologists should be treating glaucoma patients, and 57% believed GPs should have a role in management. Only 1 % supported a therapeutic role for optometrists. Major perceived barriers to glaucoma screening in the elderly were the inaccuracy of current general practice screening tools (65%) and paucity of information concerning the desirability of screening (32%). Conclusion: Brisbane general practitioners believe patients >50 years old should be screened for POAG. They advocated a role for screening by ophthalmologists, GPs and optometrists. Major perceived barriers to current screening in general practice are the inaccuracy of current general practice tools (65%) and paucity of information on the subject (32%). The majority (85%) requested further information and provision of skills in this area.     

北京市社区青光眼筛查模式初步研究

目的探讨社区青光眼筛查模式的可行性。设计人群横断面研究。研究对象北京市东城区社区≥50岁居民6886人。方法2007年9月～2008年4月在北京市东城区18个社区进行青光眼为主的眼病筛查。由社区工作人员组织,在进行视力检查及简单问卷后,在社区对所有受试者进行非散瞳眼底数码照相。眼底图像不清楚者,用眼底照相机照眼前节照片。图像上传至浏览器／服务器架构的数据库,由专业人员集中阅片。可疑青光眼的诊断主要依据视乳头及视网膜神经纤维层形态学改变,并转到专科医院进一步诊治。主要指标可疑青光眼的患病率。结果发现可疑青光眼405例（5．88％）,男性占38％,平均年龄（71．0±7．8）岁。50～59、60～69、70～79、80岁以上者分别占8．O％、24．O％、56．6％、11．4％。经北京同仁医院眼科检查后诊断青光眼146例,占可疑青光眼的36．05％,占筛查总人数的2．12％,其中87例（59．59％）不知道自己患有青光眼。此外,筛查出需手术治疗的白内障289例（4．20％）：糖尿病视网膜病变557例（8．09％）;其他眼病375例（5．45％）。结论以非散瞳数码眼底照相为基础的社区青光眼筛查模式是可行的。它可以实现对青光眼、糖尿病视网膜病变及白内障等多种致盲性眼病联合筛查。组织实施及人员培训是关键。     

The accuracy of accredited glaucoma optometrists in the diagnosis and treatment recommendation for glaucoma

Aim

To compare the diagnostic performance of accredited glaucoma optometrists (AGO) for both the diagnosis of glaucoma and the decision to treat with that of routine hospital eye care, against a reference standard of expert opinion (a consultant ophthalmologist with a special interest in glaucoma).

Methods

A directly comparative, masked, performance study was undertaken in Grampian, Scotland. Of 165 people invited to participate, 100 (61%) were examined. People suspected of having glaucoma underwent, within one month, a full ophthalmic assessment in both a newly established community optometry led glaucoma management scheme and a consultant led hospital eye service.

Results

Agreement between the AGO and the consultant ophthalmologist in diagnosing glaucoma was substantial (89%; κ = 0.703, SE = 0.083). Agreement over the need for treatment was also substantial (88%; κ = 0.716, SE = 0.076). The agreement between the trainee ophthalmologists and the consultant ophthalmologist in the diagnosis of glaucoma and treatment recommendation was moderate (83%, κ = 0.541, SE = 0.098, SE = 0.98; and 81%, κ = 0.553, SE = 0.90, respectively). The diagnostic accuracy of the optometrists in detecting glaucoma in this population was high for specificity (0.93 (95% confidence interval, 0.85 to 0.97)) but lower for sensitivity (0.76 (0.57 to 0.89)). Performance was similar when accuracy was assessed for treatment recommendation (sensitivity 0.73 (0.57 to 0.85); specificity 0.96 (0.88 to 0.99)). The differences in sensitivity and specificity between AGO and junior ophthalmologist were not statistically significant.

Conclusions

Community optometrists trained in glaucoma provided satisfactory decisions regarding diagnosis and initiation of treatment for glaucoma. With such additional training in glaucoma, optometrists are at least as accurate as junior ophthalmologists but some cases of glaucoma are missed.     

关于我国原发性闭角型青光眼筛查与诊断认识的问卷调查

目的了解眼科医生对原发性闭角型青光眼筛查和诊断的认识以及在临床实践中应用的基本情况。设计横断面调查。研究对象2005年9月11日在第十届全国眼科学术大会青光眼会场参会的眼科医生。方法采用问卷调查的形式,调查表内容包括被调查者基本信息和对闭角型青光眼诊断进展的认识以及实际工作状况。共发出330份问卷表,收回有效问卷262份（有效应答率79．4％）。主要指标问卷调查结果。结果29个省、市的眼科医生接受了本次问卷调查。96．9％的人认为我国应开展闭角型青光眼的社区筛查工作;57．3％接受国际地域性和眼科流行病学组（ISGEO）关于闭角型青光眼的分类体系,41．6％反对必须伴有视神经损害才诊断为青光眼的观念;69．1％认为以房角关闭机制为基础的闭角型青光眼分类体系对临床治疗有指导作用。在实际工作中,81．3％的人将前房角镜检查作为门诊闭角型青光眼筛查的常规手段,77．4％将暗室激发试验作为门诊早期可疑闭角型青光眼筛查的常规手段,49．2％将超声活体显微镜检查（UBM）作为可疑闭角型青光眼筛查的常规手段。而对于急性闭角型青光眼眼压下降后视神经损害的评价,80．9％的人常规进行眼底检查,仅54．6％的人常规进行眼压下降后的视野损害评价。结论我国眼科医生对于原发性闭角型青光眼的定义与分类体系的认识与国际上存在较大差异。闭角型青光眼的筛查手段及其使用在不同医院和不同知识背景的医生中具有较大的变异性。     

The value of screening for glaucoma with tonometry

This paper estimates the value of performing Schiotz tonometry to detect glaucoma in an asymptomatic patient. About 9% of adults over 40 will be found on a single Schiotz tonometry test to have elevated intraocular pressure (IOP). On work-up, about 1 out of 50 of these individuals with high IOP will be found to have glaucoma. Tonometry, however, will miss about half of all patients with glaucoma because they do not have elevated IOPs at the time of the test. Pilocarpine or epinephrine are the most commonly used drugs to treat the disease, but they are not always effective in lowering a patient's IOP or in stopping the progression of field defects. From the available evidence it does not appear that earlier diagnosis makes a substantial difference in the patient's outcome. If all individuals over 40 years of age in a city of 1,000,000 were screened, the total cost of finding and treating about 484 people with chronic simple glaucoma would be on the order of $4,944,866 or about $13,000 per patient potentially benefited. Screening with tonometry does not appear to be warranted.     

Diagnosis and management of open angle glaucoma: suggested guidelines for optometrists

Objective : The aims of this review are to define open angle glaucoma, to outline its prevalence and its financial and personal costs, to discuss the difficulties encountered in establishing the diagnosis and monitoring treatment, and to suggest initial clinical guidelines for the comanagement of glaucoma between ophthalmologists and optometrists. Methods : The literature was selectively reviewed to permit deductions that can be directed toward an effective comanagement strategy for patients with open angle glaucoma. Conclusions : Comanagement of patients having open angle glaucoma is a viable option, provided the opportunity for improved monitoring and better compliance is available. The basis for successful management rests with the ability to detect change in the optic disc and surrounding retina, visual fields and intraocular pressure. All these signs are continuous variables for which there are no known limits of normality. The division of responsibilities of management will be established initially by legislation and in the future modified according to experience and the emergence of new therapies.     

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.     

Intraocular pressure adjusted for central corneal thickness as a screening tool for open-angle glaucoma in an at-risk population

Objective: Evaluation of intraocular pressure (IOP) adjusted for central corneal thickness (CCT) screening for open-angle glaucoma (OAG) in an at-risk population.Study Design: Community-based screening clinic.Participants: Three hundred and forty-nine persons of black race, or >50 years of age, or with a positive family history of glaucoma.Methods: Ophthalmological examination including Goldmann applanation tonometry, ultrasonographic corneal pa-chymetry, and visual field testing. Glaucomatous optic nerve damage with visual field loss was the gold standard. IOP was adjusted for CCT based on 3 nomograms. Results were compared with screening using unadjusted IOP. Outcome measures included sensitivity, specificity, areas under the receiver operating characteristic (ROC) curves, positive and negative predictive values (PPVs and NPVs), as well as positive and negative likelihood ratios.Results: No significant difference in CCT was found between those with glaucoma (560 [SD 37] µm, n = 31) and those without (557 [SD 35] um, n = 233). Screening adjusted IOPs for glaucoma with an IOP > 21 mm Hg resulted in PPVs of 23.8% to 25% and NPVs of 89.3% to 89.6%, similar to preadjustment values. Areas under the ROC curves varied from 0.544 to 0.571 post adjustment from the initial value of 0.574.Conclusions: IOP adjusted for CCT is unlikely to improve tonometry as a screening tool for OAG in an at-risk population.     

Clinical analysis of screening and threshold visual field data for glaucoma detection

The value of clinical interpretation in differentiating between glaucomatous and normal fields from threshold (Humphrey Field Analyser) and screening (Henson CFS3000) measures was determined using a masked prospective experimental design. The visual field plots of 20 primary open-angle glaucoma (POAG) patients, 19 ocular hypertensive and 19 normotensive glaucoma suspects, and 21 age- matched normals measured with the Humphrey Field Analyser (Humphrey) and Henson CFS3000 (Henson) were categorised by two experienced clinicians. Significant differences in interpretation of the field plots were demonstrated between the two clinicians (χ^{2 McNemars}= 19–36; p<0.001). The sensitivity of clinical interpretation was shown to lie between 65 per cent and 90 per cent (dependent upon the individual clinician) for the Humphrey plots, but was as low as 40 per cent with the Henson plots. Specificity was, however, higher for the Henson overall, regardless of the clinician (between 90 per cent and 95 per cent) compared to the Humphrey (between 75 per cent and 100 per cent). These levels of sensitivity and specificity do not reach the levels reported when interpretation is based on the visual field indices alone. It was concluded that a screening instrument, such as the Henson, should only be employed for testing large unselected populations, in which the prevalence of glaucoma is low. Visual fields should not be judged in isolation, but in conjunction with measures of optic nerve and nerve fibre layer integrity, intra-ocular pressure and family history.     

Ahmed青光眼阀植入术治疗难治性青光眼的临床观察

目的探讨Ahmed青光眼阀植入术治疗难治性青光眼的临床效果。方法回顾性分析20例(20 只眼)难治性青光眼行Ahmed阀植入术后眼压、视力及并发症的情况。随访时间2周～32月。结果 Ahmed阀植入术治疗20例(20只眼)难治性青光眼成功率达70％。至最后一次随访,20例(20只眼)术前平均眼压(59．61 ±19．25)mmHg,术后平均眼压(16．22±5．17)mmHg,与术前相比明显降低,差异有统计学意义(P<0．01)。术后视力保持原水平12只眼,视力提高4只眼,视力下降4只眼。除1只眼发生恶性青光眼以外,其余并发症如前房积血、浅前房、脉络膜脱离、虹膜阻塞导管口、局限性视网膜浅脱离等经治疗后好转。结论对于难治性青光眼, Ahmed青光眼阀植入术能取得良好的疗效,具有较好的临床应用价值。     

Issues in the epidemiology and population-based screening of primary angle-closure glaucoma

Among Caucasians, it is well known that 75–95% of primary glaucoma is due to open-angle glaucoma (POAG), with angle-closure (PACG) comprising only a very small minority of cases. These figures are reversed among other groups such as Asians and Eskimos, where PACG makes up 80–90% of primary glaucoma. Among Eskimos, the prevalence of PACG has been reported as 2–8%, as compared to 0.1% among Caucasians. It appears that a population tendency toward shallow anterior chambers may explain the excess burden of PACG morbidity. Among Asians, the prevalence of PACG is intermediate between Caucasians and Eskimos. Existing biometrical data do not show a clear tendency toward shallower anterior chambers among Asians. PACG may be screened for on a population basis by means of various techniques that estimate axial or limbal anterior chamber depth, measure intraocular pressure, or evaluate the optic disc or visual fields. Demographic information and medical and family history will also be of great importance in screening for PACG in large populations. Groups at increased risk for the disease include women, individuals over 50, first-degree relatives of PACG probands, and hyperopes.