OPTOMETRY RESEARCH PAPER. Accuracy of vision technicians in screening ocular pathology at rural vision centres of southern India

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1 C L I N I C A L A N D E X P E R I M E N T A L OPTOMETRY RESEARCH PAPER Accuracy of vision technicians in screening ocular pathology at rural vision centres of southern India Clin Exp Optom 2016; 99: Vasantha Suram* MD Uday Kumar Addepalli,,,** BOpt Sannapaneni Krishnaiah PhD Vilas Kovai, PhD Rohit C Khanna,, MD MPH *A C Subba Reddy Government Medical College, Nellore, Andhra Pradesh, India Allen Foster Community Eye Health Research Center, Gullapalli Pratibha Rao-International Center for Advancement of Rural Eye care, LV Prasad Eye Institute, Hyderabad, India Brien Holden Eye Research Centre, LV Prasad Eye Institute, Banjara Hills, Hyderabad, India Health Promotion, Public Health Foundation of India, New Delhi, India Brien Holden Vision Institute, Sydney, Australia V S T Center for Glaucoma Services, L V Prasad Eye Institute, Banjara Hills, Hyderabad, India ** Vision Cooperative Research Centre, Sydney, Australia Health Promotion Services, Population Health, South Western Sydney Local Health District, Sydney, Australia School of Optometry and Vision Science, University of New South Wales, Sydney, Australia rohit@lvpei.org Submitted: 5 May 2015 Revised: 2 August 2015 Accepted for publication 16 July 2015 DOI: /cxo Background: There is paucity of data on the inter-observer agreement and diagnostic accuracy between a primary-care technician (vision technician) and an ophthalmologist. Hence, the current study was conducted to assess the accuracy of vision technicians, to screen potentially sight-threatening ocular conditions at rural vision centres of southern India and their agreement with an ophthalmologist. Methods: In July to August 2010, patients presenting to seven vision centres in Adilabad district (Andhra Pradesh) were selected and screened in a masked manner by seven vision technicians followed by an examination by a consultant ophthalmologist. Agreement was assessed between vision technicians and the ophthalmologist for screening of potential sightthreatening ocular conditions and decisions for referral. The ophthalmologist s findings were considered as the reference standard. Results: Two hundred and seventy-nine patients were enrolled at seven vision centres with a mean age of 32.9 ± 21.8 years. Agreement for screening of ocular pathology was 0.82 (95 per cent CI, ). There was excellent agreement for cataract (0.97; 95 per cent CI, ), refractive error (0.98; 95 per cent CI, ), corneal pathology (1.0; 95 per cent CI, ) and other anterior segment pathology (0.95; 95 per cent CI, 0.9-1); the agreement was moderate to fair for detection of glaucoma suspects (0.43; 95 per cent CI, ) and retinal pathology (0.39; 95 per cent CI, ). Sensitivity for screening of anterior segment pathology was per cent. There was a fair to moderate sensitivity for glaucoma suspect; 35.6 per cent (95 per cent CI, ) and retinal pathology 26.3 per cent (95 per cent CI, ). Specificity for screening of ocular pathology was 98.2 to 100 per cent. The kappa (κ) agreement for referral for any pathology was 0.82 ( ) Conclusion: As there is good agreement between the vision technicians and the ophthalmologist for screening and referral of anterior segment pathology but moderate to fair for glaucoma suspects and retinal pathology, vision technicians would be a good resource at the primary level to screen for anterior segment pathology; however, they may need further training to detect posterior segment pathology. Key words: ophthalmologist, referral, screening, vision centre, vision technician According to the World Health Organization s definition, globally there are 32.4 million people blind with higher proportions of blindness in developing countries than developed countries. 1 The rate of reduction in blindness is also lower in developing countries than developed countries. 1 Shortage of trained human resources in developing nations, especially in rural areas, is considered to be one of the major hindrances. The issue is worsened by political, infrastructural and financial constraints in the national health systems of developing countries. 2 4 In such a scenario, a shared care between different ophthalmic professions is expected to bring about a synergistic effect on augmented delivery of eye care. 5 The LV Prasad Eye Institute (LVPEI) pyramidal model is one model for eye-care delivery. 6,7 The model has different layers of eye-care delivery with each layer having clear delineation and demarcation of functions. At the lower level of the pyramid is a vision centre (VC), which caters to a population of 50,000 and is managed by a one-year trained primary eye care technician known as a vision technician (VT). The main function of a vision technician is refraction and dispensing of glasses, recognition of potentially blinding and non-blinding ocular conditions and their referral to a higher centre for further management. The vision technician is certified to perform history taking, visual acuity assessment, refraction, slitlamp examination, applanation tonometry, undilated fundus examination and to prescribe glasses. Apart from that, if deemed necessary, they can also be trained to perform procedures like perimetry and other diagnostic procedures. Patients seek eye care at vision centres; those requiring further evaluation are referred to the ophthalmologist at a secondary centre, which handles referrals from 10 vision centres around it. 6,7 Issues at the primary-secondary interface include decisions to refer, appropriateness of referrals, variation in referral rates, outcome of referrals and communication. Data are available on agreement between optometrists and ophthalmologists 8 12 but there is a paucity of data on the inter-observer 183

2 agreement and diagnostic accuracy between a vision technician and an ophthalmologist. Hence, the current study was conducted to assess the accuracy of vision technicians, to screen potentially sight-threatening ocular conditions at rural vision centres of southern India and their agreement with an ophthalmologist. MATERIALS AND METHODS Study area The geographic area for the study sample includes seven vision centres in seven villages of Mudhole Mandal (sub-district) of Adilabad district in the state of Andhra Pradesh, southern India (Figure 1). All patients attending the seven vision centres during a one-week period during July and August 2010 were selected and included in the study. Sampling procedure With the assumption that the vision technician could identify 60 per cent of significant ocular pathology and that the ophthalmologist further improves detection of abnormality by an additional 20 per cent, the sample needed is 246 subjects with ocular pathology (with alpha error of five per cent). The reference standard was a consultant ophthalmologist, who was also a fellowship-trained glaucoma specialist. The Ethics Committee of LVPEI approved this study, which adhered to the tenets of the Declaration of Helsinki for research involving human subjects. Study protocol The examination protocol at vision centres is given in Figure 2. The ophthalmologist went weekly to each vision centre. During the week, the vision technician as well as the ophthalmologist independently examined all the patients coming to the vision centre. Written informed consent was obtained from all the patients who underwent screening. Examination by a vision technician included clinical history, external torch light examination, objective and subjective refraction, slitlamp examination with an undilated pupil, tonometry and examination of the fundus through an undilated pupil with a direct ophthalmoscope. All of these observations were recorded on the data collection forms, which had self-coded options for every question. Figure 1. Map showing the study location Clinical and Experimental Optometry 99.2 March Optometry Australia

3 Figure 2. Flowchart showing the examination protocol This was followed by an examination by the ophthalmologist, who did an examination similar to the vision technician and in addition, did the dilated fundus examination. Data collection forms were completed both by the vision technician and the ophthalmologist independently in a masked manner. The reference standard diagnosis was a dilated examination conducted by the ophthalmologist. Quality control checks were done on a daily basis by the study co-ordinator who manually checked each form for completion. The criteria for referral to higher centres by the vision technician were at least one of the following criteria: 1. any patient whose visual acuity did not improve to at least 6/12 for distance and/or N6 for near in either eye with spectacle correction 2. those with shallow anterior chamber (less than 0.25 by Van Herrick technique) and/ or raised intraocular pressure (20 mmhg or more) 3. those with any anterior and/or any retinal pathology / abnormality 4. those with ocular trauma, active infection or unexplained loss of vision and 5. any retinal pathology ranging from a simple microaneurysm to a combination of findings. Definitions Blindness and visual impairment (VI) was defined as per WHO definition. 13 Blindness was defined as presenting visual acuity (PVA) less than 3/60 in the better eye, severe visual impairment (SVI) as presenting visual acuity less than 6/60 to 3/60 in the better eye and visual impairment as presenting visual acuity less than 6/18 to 6/60 in the better eye Definitions of ocular conditions are listed in Table 1. The primary diagnosis for each person was given for the eye with worse visual acuity. If the visual acuity was the same, diagnosis of the eye with the avoidable cause was labelled for the person. Statistical analysis Descriptive statistics including mean, standard deviation (SD) and range were calculated for all the normally distributed variables. Agreement between a vision technician and the ophthalmologist was determined using the weighted kappa statistic. 14 The weighted kappa is a good indicator of intra-class correlation for ordinate data. The Chi-square and t-tests were used for univariate analyses. Statistical analyses were performed using commercial software (Stata version 11; StataCorp, College Station, Texas, USA). A p-value of less than 0.05 was considered statistically significant. RESULTS Two hundred and seventy-nine subjects were enrolled and examined from the seven vision centres. The mean age in the study group was ± years. Nearly 54 per cent (150 subjects) were older than 30 years of age. There were 128 males (45.9 per cent). Condition Definition Cataract Visible opacity in pupillary area impairing vision (less than 6/18) and part or complete obscuration of red reflex on distant direct ophthalmoscope Corneal opacity Nebular, macular or leucomatous corneal opacity involving the pupillary area, causing decreased visual acuity and/or symptoms Glaucoma suspect Based on any one of the criteria: intraocular pressure 20 mmhg or more in either eye and/or shallow anterior chamber (less than 0.25 by Van Herrick technique) and /or abnormal appearance of optic disc, which include any one or more of the following: vertical cup/ disc ratio of 0.65 or more; disc notch, haemorrhage or nerve fibre layer defect; neuroretinal rim less than 0.2 in any quadrant, disc asymmetry 0.2 Retinal pathology Presence of hard or soft drusen, retinal pigment epithelium changes, micro-aneurysms, haemorrhages, hard or soft exudates, venous beading, intraretinal microvascular abnormalities, new vessels elsewhere (NVE) geographic atrophy, choroidal neovascular membranes (CNVM), disciform scar, macular oedema; epiretinal membranes (ERM), vascular occlusions, degenerations, nonglaucomatous optic atrophy et cetera Others Those which did not fit into any of the above categories Table 1. Definitions of ocular conditions 185

4 Ophthalmological examination revealed that 279 subjects were diagnosed to have 279 ocular conditions by the ophthalmologist and 250 ocular conditions by the vision technicians (Table 2). Cataract and refractive error accounted for nearly 60 per cent of ocular conditions. Table 2 also shows the overall agreement for various ocular conditions between the ophthalmologist and vision technicians. Table 3 shows the sensitivity, specificity, positive predictive values and negative predictive values for various ocular conditions between the ophthalmologist and the vision technicians. There was good agreement for the diagnosis of cataract, refractive error, corneal pathology and other anterior segment disorders. The agreement was moderate to fair for the diagnosis of glaucoma suspects and retinal pathology. The overall kappa (κ) for agreement for referral between the vision technicians and ophthalmologist was The sensitivity for diagnosis of cataract, refractive error, corneal disorders and other pathology was good (94.6 to 100 per cent). It was moderate to fair for glaucoma suspects (35.6 per cent; 95 per cent CI, ) and retinal pathology (26.3 per cent; 95 per cent CI, ). The specificity for ocular pathology (including refractive error) was between 98.2 to 100 per cent. DISCUSSION In developing countries, to improve the efficiency of health-care services and bridge the gap of trained human resources in rural areas, alternative sources for identifying mid-level cadre staff have been tried. 5 These human resources are identified locally, trained and placed back into the same location, thus bridging the human resource gap. This has the advantage of creating local employment, having sustainable human resources in these places and reduced cost. The concept of vision centres is similar and has also been adopted by VISION 2020, the Right to Sight Initiative. 15 In addition, the Indian government has included this model in the National VISION 2020 program in the five-year plan for 2007 to Despite broad acceptance of this model, the ability of vision technicians to screen for potentially sight-threatening ocular conditions at rural vision centres and their agreement with an ophthalmologist has not been previously studied. To our knowledge, this is the first study to show the inter-observer agreement and diagnostic accuracy between a vision technician and an ophthalmologist in the developing world. Additionally, it reports the differences in agreement for anterior or posterior segment pathology. Although the agreement as well as sensitivity was good for anterior segment pathology, it was moderate to fair for posterior segment pathology. This is in agreement with other published studies. 10,11,16 18 This could be due to the fact that the vision technician does an undilated evaluation with a direct ophthalmoscope in comparison with that of a reference standard diagnosis, which was made after a proper dilated evaluation by an ophthalmologist. Using a direct ophthalmoscope with an undilated pupil itself hinders a proper examination of the fundus due to small pupils, media opacities et cetera. The implications of these findings are that vision technicians are a suitable human Ophthalmologist Vision technician Diagnosis Number (%) Number (%) Kappa (95 per cent CI) Refractive error 107 (38.4) 110 (44) 0.98 ( ) Cataract 54 (19.4) 55 (22) 0.97 ( ) Corneal pathology 21 (7.5) 21 (8.4) 1.0 ( ) Glaucoma suspect 41 (14.7) 22 (8.8) 0.43 ( ) Retinal pathology 19 (6.8) 6 (2.4) 0.39 ( Others 37 (13.3) 36 (14.4) 0.95 ( ) Total 279 (100) 250 (100) 0.82 ( ) Table 2. Ocular conditions in the study population as determined by vision technicians and the ophthalmologist and their agreement Diagnosis Sensitivity (95 per cent CI) Specificity (95 per cent CI) PPV (95 per cent CI) NPV (95 per cent CI) Cataract 98.1 ( ) 99.4 ( ) 96.4 ( ) 99.7 ( ) Refractive error 100 ( ) 98.9 ( ) 97.3 ( ) 100 ( ) Cornea pathology 100 ( ) 100 (99-100) 100 ( ) 100 (99-100) Glaucoma suspect 35.6 ( ) 98.2 ( ) 72.7 ( ) 91.8 ( ) Retinal pathology 26.3 ( ) 99.7 ( ) 83.3 ( ) 96.2 ( ) Others 94.6 ( ) 99.7 ( ) 97.2 ( ) 99.4 ( ) PPV: positive predictive value, NPV: negative predictive value, CI: confidence interval Table 3. Agreement between the ophthalmologist and vision technicians and sensitivity, specificity, positive predictive value and negative predictive value of vision technicians Clinical and Experimental Optometry 99.2 March Optometry Australia

5 resource cadre at vision centre level, especially to screen, identify and refer people with sight-threatening conditions due to anterior ocular disorders such as refractive errors, cataract and corneal pathology. As these ocular conditions affect millions of people in developing countries including India, involvement of trained vision technicians to address the issues of primary eye care in inaccessible geographical regions is an appropriate intervention. While there is moderate to fair agreement for detection of posterior segment pathology by the vision technicians, diagnostic accuracy could improve by addition of diagnostic equipment at the vision centre, such as frequency doubling technology (FDT), a non-mydriatic fundus camera and other low-cost imaging modalities. A limitation of the current study was that we did not look at diagnostic accuracy of specific sight-threatening conditions, such as diabetic retinopathy, age-related macular degeneration or other posterior segment pathology. Apart from this, the result of the study would have limited extrapolation and would be applicable only to those primary eye-care technicians who have undergone the one-year training program at the LVPEI. In conclusion, the study results show that the vision technician could detect most anterior segment disorders but missed a significant amount of posterior segment diseases. Given the duration and type of vision technician training, refresher training might be useful for detection of more ocular pathology. ACKNOWLEDGEMENT We would like to acknowledge all the vision technicians and the participants of the study. We would also like to acknowledge the Andhra Pradesh Right to Sight Society for funding part of the study. Finally, we would like to thank Professor Jill Keeffe for her critical comments for the manuscript. REFERENCES 1. Stevens GA, White RA, Flaxman SR, Price H, Jonas JB, Keeffe J et al. Global prevalence of vision impairment and blindness: magnitude and temporal trends, Ophthalmology 2013; 120: Dandona L, Dandona R, Srinivas M, Giridhar P, Vilas K, Prasad MN et al. Blindness in the Indian state of Andhra Pradesh. Invest Ophthalmol Vis Sci 2001; 42: Murthy GV, Gupta SK, Bachani D, Jose R, John N. Current estimates of blindness in India. Br J Ophthalmol 2005; 89: Thulasiraj RD, Nirmalan PK, Ramakrishnan R, Krishnadas R, Manimekalai TK, Baburajan NP et al. Blindness and vision impairment in a rural south Indian population: the Aravind Comprehensive Eye Survey. Ophthalmology 2003; 110: Mullan F, Frehywot S. Non-physician clinicians in 47 sub-saharan African countries. Lancet 2007; 370(9605): Rao GN. An infrastructure model for the implementation of VISION 2020: the right to sight. Can J Ophthalmol 2004; 39: Rao GN, Khanna RC, Athota SM, Rajshekar V, Rani PK. Integrated model of primary and secondary eye care for underserved rural areas: the L V Prasad Eye Institute experience. Indian J Ophthalmol 2012; 60: Burnett S, Hurwitz B, Davey C, Ray J, Chaturvedi N, Salzmann J et al. The implementation of prompted retinal screening for diabetic eye disease by accredited optometrists in an inner-city district of North London: a quality of care study. Diabet Med 1998; 15(Suppl 3): S38 S Buxton MJ, Sculpher MJ, Ferguson BA, Humphreys JE, Altman JF, Spiegelhalter DJ et al. Screening for treatable diabetic retinopathy: a comparison of different methods. Diabet Med 1991; 8: Hau S, Ehrlich D, Binstead K, Verma S. An evaluation of optometrists ability to correctly identify and manage patients with ocular disease in the accident and emergency department of an eye hospital. Br J Ophthalmol 2007; 91: Paudel P, Cronje S, O Connor PM, Rao GN, Holden BA. Selection considerations when using a standard optometrist to evaluate clinical performance of other eyecare personnel. Clin Exp Optom 2014; 97: Spry PG, Spencer IC, Sparrow JM, Peters TJ, Brookes ST, Gray S et al. The Bristol Shared Care Glaucoma Study: reliability of community optometric and hospital eye service test measures. Br J Ophthalmol 1999; 83: [Accessed 6May,2014]. 14. Cohen J. Weighted kappa: nominal scale agreement with provision for scaled disagreement or partial credit. Psychol Bull 1968; 70: WHO. Strategic Plan for Vision 2020: The Right to Sight Elimination of Avoidable Blindness in the South-East Asia Region. WHO 2000; Project 2002: Pierscionek TJ, Moore JE, Pierscionek BK. Referrals to ophthalmology: optometric and general practice comparison. Ophthalmic Physiol Opt 2009; 29: Sheldrick JH, Vernon SA, Wilson A. Study of diagnostic accord between general practitioners and an ophthalmologist. BMJ 1992; 304(6834): Thomas R, Naveen S, Nirmalan PK, Parikh R. Detection of ocular disease by a vision-centre technician and the role of frequency-doubling technology perimetry in this setting. Br J Ophthalmol 2010; 94:

Glaucoma at a tertiary referral eye hospital in Nepal

Original article Glaucoma at a tertiary referral eye hospital in Nepal Paudyal I 1,Thapa S S 1, Paudyal G 2, Gurung R 2, Ruit S 2 1 Nepal Glaucoma Eye Clinic, Tilganga Institute of Ophthalmology, Kathmandu,