ORIGINAL ARTICLE  
Diagnostic Accuracy of Direct  
Ophthalmoscopy and Non-Mydriatic Retinal  
Photography for Screening of Diabetic  
Retinopathy  
Muhammad Saleh Memon1, Shahid Ahsan2, Muhammad Fahadullah3  
Khalida Parveen4, Sumaira Salim5, Muhammad Faisal Fahim6  
13’4’5’Al-Ibrahim Eye Hospital, Isra Postgraduate institute of Ophthalmology, Karachi, 2Jinnah Medical and Dental  
College, Karachi, 6Bahria University Medical and Dental Collage, Karachi  
ABSTRACT  
Purpose: To determine the reliability of direct ophthalmoscopy and Non-Mydriatic fundus photography for  
screening of Diabetic Retinopathy by optometrist.  
Study Design: Observational, cross sectional.  
Place and Duration of Study: Al-Ibrahim eye hospital, Karachi from October to December 2018.  
Material and Methods: All individuals with type 2 diabetes of ≥ 40 years of age were screened for diabetic  
retinopathy (DR) by two trained optometrists and an ophthalmologist. First Optometrist used Non Mydriatic  
Fundus Camera (NMFC) and second optometrist used direct ophthalmoscopy (DO) after dilating the pupils. Final  
examination was done by the Ophthalmologist with slit lamp using Volk fundus lens which was considered as  
reference standard. Every investigator was kept unaware of the findings of others.  
Results: A total of 698 eyes of 349 respondents were screened. Ophthalmologist could not make decision by bio  
microscopy in 44 (6.3%) individuals as compared to 128 (18.3%) by 1st optometrist by NMFC and 142 (20.3%) by  
2nd optometrist with DO. Diabetic retinopathy (DR) diagnosed with slit lamp bio microscopy was 140 (21.4%), with  
NMFC was 124 (19.1%), with DO was 110 (16.8%). Sensitivity of NMFC was 76% and that of DO was 64.8%.  
Specificity of NMFC was 97.45% and that of DO was 96.63%. Positive predictive value (PPV) of NMFC was  
89.33% and that of DO was 84.3% Negative predictive value (NPV) of NMFC was 93.33% and that of DO was  
90.7%.  
Conclusion: NMFC is recommended tool for DR screening; but DO by well-trained optometrist can be reliable  
where neither ophthalmologist nor NMFC is available.  
Key Words: Diabetic Retinopathy, Direct ophthalmoscopy, Non Mydriatic fundus camera, Optometrist.  
How to Cite this Article: Wali FS, Surhio SA, Talpur R, Jawed M, Shujaat S. Change in Central Corneal  
Thickness after Phacoemulsification. Pak J Ophthalmol. 2020; 36 (2): 120-124.  
Doi: 10.36351/pjo.v36i2.1015  
INTRODUCTION  
Correspondence to: Muhammad Saleh Memon  
Director Research, Isra Ophthalmic Research &  
Development Center, Al-Ibrahim Eye Hospital  
Diabetic retinopathy is one of the leading causes of  
avoidable blindness in people of working age group1,2.  
It has been shown that diabetic retinopathy (DR) is  
present in 28.78% diabetics whereas sight threatening  
diabetic retinopathy (STDR) is present in 8.6% of the  
Isra Postgraduate Institute of Ophthalmology  
Karachi  
Pakistan Journal of Ophthalmology, 2020, Vol. 36 (2): 120-124  
120  
Shahid Ahsan, et al  
diabetics3. The most recent survey of diabetes4 in  
Pakistan reported 26.3% prevalence of diabetes, of  
which 19.2% had known diabetes and 7.1% were  
diagnosed on screening. In order to prevent  
progression of DR to STDR leading to gross impaired  
vision, at least all the known diabetics should undergo  
annual DR screening as per recommendations5,6. It is  
commonly observed in clinical practice that many  
individuals having diabetes in Pakistan present with  
varying degree of retinopathy and visual deterioration  
on their first presentation, jeopardizing the final visual  
outcome. This state of affairs may arise either from  
failure to detect retinopathy at an appropriate stage or  
a delay in treatment7. Diversity of the tools and  
operators has resulted in marked variations in the  
results attributed not only to modality by which  
screening was performed but to the expertise of the  
health care provider. Developed countries have their  
own screening methodologies8. Developing countries  
have to find out screening methods which are not only  
feasible, cost-effective but meet international  
standards of > 80% sensitivity, and > 95% specificity9.  
(Standards set by British Diabetic Association (BDA).  
Though Pakistan has an elaborative network of health  
care facilities at primary, secondary and tertiary care  
level, a proper functioning referral system is lacking10.  
This situation is further accentuated by shortage of  
trained and qualified ophthalmologists. Currently,  
country has nearly 30,000 qualified registered  
ophthalmologists against the required number of  
100,00011. Thus mandatory screening of all patients by  
ophthalmologist as per recommended guidelines is out  
of questions for a long time to come. Non-Mydriatic  
fundus camera (NMFC) has been recommended as  
useful tool for mass screening12. It can be used at  
primary/secondary level by trained paramedics to  
lessen the burden on ophthalmologist and meet the  
required criteria. The cost and maintenance prevents  
its use in resource strained country like ours. Direct  
ophthalmoscopy in the hands of well-trained  
optometrist might be a cheaper method. A study  
carried in a tertiary care diabetes center reported  
sensitivity of 60% and specificity of 76%13. The  
findings of this study though did not validate the use  
of direct ophthalmoscopy by Diabetologist; authors  
however advocated its use and suggested to invest on  
the training of health care providers till financial  
resources allow shifting to the modern technology like  
fundus camera. In another study from Lahore, ―direct  
ophthalmoscopy‖ in the hands of ophthalmologist  
considering as gold standard was compared to "Arc  
light‖, concluded that ―Arc light‖ can be used as a  
replacement of Ophthalmoscope for diagnosing DR or  
other diseases as shown by the sensitivity and  
specificity analysis in this study‖. The researcher  
found optometrist almost equal to ophthalmologist in  
diagnosis of DR with ophthalmoscope as well as ―Arc  
light14 Apart from this study, sensitivity and specificity  
of ―direct ophthalmoscope‖ in the hands of optometrist  
has been scarcely studied in Pakistan. Present study  
was conducted with two objectives. First, to validate  
the findings of an earlier study using NMFC by  
optometrist. Second, to find out the diagnostic  
accuracy of direct ophthalmoscopy in the hands of  
optometrist. The standard reference in the present  
study was bio-microscopy with 90D fundus lens by  
ophthalmologist.  
MATERIAL AND METHODS  
This was a comparative cross sectional study with  
non-probability, purposive sampling, carried out at  
diabetic eye clinic of Al Ibrahim eye hospital (AIEH).  
Duration of the study was from October to December  
2018. All newly registered type 2 patients with  
diabetes, ≥ 40 years of age, irrespective of gender and  
ethnicity and willing for eye examination with dilated  
pupil were inducted whereas patients with type 1 and  
gestational diabetes or patient having any other eye  
disease were excluded from the study. All patients  
were examined for routine basic eye examination like  
refraction and best-corrected vision and entered into  
database. First screening was carried by an optometrist  
(Optometrist A) without dilatation of pupil. Two 45  
degree retinal images one center to macula and other  
center to optic disc were taken using Non Mydriatic  
fundus camera (NMFC) (Cannon CR-1). The data of  
fundus image was saved in the HMIS (AIEH)  
database. The consent was obtained from the patient  
for dilatation of pupil after informing about  
transitional haziness of vision after dilatation and  
confirming that patient is not driving after  
examination. Tropicamide 0.1% was used for  
dilatation of pupil. After full mydriasis, Optometrist  
(Optometrist B) examined the fundus with direct  
ophthalmoscopy and entered the data in the HMIS  
(AIEH) database. The optometrists were instructed to  
identify presence or other wise of the diabetic  
retinopathy based on presence of hemorrhages,  
exudates, blood vessel changes and macular edema.  
They did not grade the retinopathy. In order to  
eliminate the observer bias both optometrists were  
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Diagnostic Accuracy of Direct Ophthalmoscopy and Non-Mydriatic Retinal Photography by Trained Optometrists for Screening of Diabetic  
Table 1: N: 698 eyes (349 individuals with diabetes).  
kept blind to the findings of each  
other. Final retinal examination (C)  
was done by the retina-trained  
ophthalmologist using fundus lens  
and slit lamp. Findings were entered  
into HMIS database. These findings  
were taken as the reference standard  
for this study. DR was classified as  
Diagnosis Not  
Possible  
Tool used  
Examiner  
DR Detection  
NMFC  
Direct ophthalmoscopy  
Slit lamp bio-microscopy  
Optometrist  
Optometrist  
Ophthalmologist  
(n: 142) 20.3%  
(n:128) 18.3%  
(n:44) 6.3%  
(n:124) 19.1%  
(n: 110) 16.8%  
(n: 140) 21.4%  
Table 2: Validity chart n = 698 eyes (349 individuals with diabetes).  
a
routine examination for the  
purpose of management using  
―Early treatment diabetic  
retinopathy study (ETDRSthe  
modified Airlie House  
classification. DR was classified as  
NonProliferative Diabetic  
Kappa  
Statistic  
Sensitivity Specificity PPV  
NPV  
British Diabetic Association  
(BDA) recommendations  
NMFC  
> 80%  
> 95%  
-
-
-
76%  
97.45%  
96.63%  
89.62% 93.33% 0.725  
84.38% 90.72% 0.621  
Direct ophthalmoscopy  
64.80%  
*Positive Predictive value (PPV), Negative Predictive value (NPV)  
Retinopathy (NPDR), Proliferative  
Diabetic Retinopathy (PDR) and  
clinically significant Macular Edema (CSME) with or  
without NPDR/PDR. For the purpose of present study  
presence or absence of DR alone was compared with  
findings of NMFC done by Optometrist A and direct  
ophthalmoscopy done by Optometrist B.  
diagnosed with slit lamp bio microscopy was 140  
(21.4%), with NMFC was 124 (19.1%), with DO was  
110 (16.8%) (Table 1). Validity of the procedures is  
shown in Table 2.  
Kappa statistic in terms of DR detection by NMFC  
as compared to slit lamp diagnosis (standard) was  
found to be 0.725. This indicates good agreement  
between the observers of NMFC with standard. Kappa  
statistic in terms of DR detection with Direct  
Ophthalmoscopy (DO) as compared to slit lamp  
diagnosis (standard) was found to be 0.621. This also  
shows good agreement between the observers of DO  
with standard.  
Sample size calculation drawn by using on-line  
software Raosoft.com and inculcating 95% confidence  
interval, given 5% margin of error with expected  
population size 5000 per year. The required sample  
size was found to be 357. Ethical approval was taken  
from Research Ethical Committee (REC) of Isra Post  
Graduate Institute of Ophthalmology, Al Ibrahim Eye  
Hospital (AIEH). Statistical analysis was done by  
SPSS version 20.0. The entire continuous variables  
were presented as mean ± standard deviation. All the  
categorical variables were shown as frequency and  
percentage. Sensitivity, specificity, PPV, NPV and  
likelihood ratio was calculated by 2 × 2 contingency  
table. Kappa statistics was also done to show the  
association (level of agreement) between two  
observers.  
DISCUSSION  
Present study showed NMFC in the hands of an  
optometrist has sensitivity of 76%, specificity of  
96.63%, PPV of 84.3% and NPV of 90.7%. Findings  
of the present study not only validated the findings of  
earlier study with NMFC by optometrists but showed  
improvement over previous figures of 72% sensitivity,  
86.3% specificity, 62% positive predictive value and  
90% negative predictive value. Several studies have  
evaluated Non-Mydriatic fundus photography, and  
compared it with more-established methods of  
detecting diabetic retinal disease. The real question to  
be considered is whether Non-Mydriatic fundus  
photography will help to detect early treatable  
retinopathy better than the average physician using  
ophthalmoscopy15-18. This study thus supports that  
Digital photography with NMFC camera is a useful  
tool for mass screening. It is to be considered that  
Initial cost of NMFC is ≥ $ 20,000 and maintenance  
RESULTS  
A total of 698 eyes of 349 individuals with diabetes  
type 2 were screened for DR using NMFC without  
dilating pupil, using direct ophthalmoscope (DO) after  
dilating pupil and slit lamp with Volk’s lens. Result of  
slit lamp examination was used as a reference standard  
for comparison of NMFC ophthalmoscopy.  
Non-Readable fundi with bio microscopy were 44  
(6.3%), with NMFC were 142 (20.3%) and with DO  
were 128 (18.3%). Diabetic retinopathy (DR)  
Pakistan Journal of Ophthalmology, 2020, Vol. 36 (2): 120-124  
122  
Shahid Ahsan, et al  
limits use for screening of retinopathy and calls for  
more cost effective methodology. Ophthalmoscope is  
economical, age-old equipment which has been used  
by general physician, Diabetologists, opticians and  
nurses. Direct ophthalmoscopy by an optometrist can  
be most cost effective tool especially in community  
screening and primary eye care centers only if it meets  
the recommended criteria. Present study has shown  
that direct ophthalmoscopy in the hands of optometrist  
had Sensitivity of 64.8%, Specificity of 96.63% with  
PPV of 84.3% and NPV of 90.7%. The results have  
fallen short of recommended levels by BDA of > 80%  
sensitivity, and > 95% specificity. This shows that in  
100 DR eyes, optometrist missed 34 cases and  
wrongly diagnosed 4 cases. Results of International  
studies are variable. Studies from the UK have shown  
sensitivity levels for the detection of sight-threatening  
diabetic retinopathy of 41 67% for general  
practitioners, 48 82% for optometrists, 65% for an  
ophthalmologist, and 27 67% for Diabetologist and  
well-trained optometrist can be depended upon in the  
primary care setups and in the community where  
neither ophthalmologist nor NMFC is available.  
ACKNOWLEDGEMENT  
We are thankful to Sight savers for their technical and  
financial support through the entitled project  
―Strengthening Pakistan’s response to Diabetic  
retinopathy‖.  
Ethical Approval  
The study was approved by the Institutional review  
board/Ethical review board.  
Conflict of Interest  
Authors declared no conflict of interest  
hospital physicians using direct ophthalmoscopy19,20  
This shows missing rates, of DO for sight threatening  
diabetic retinopathy screening with direct  
.
AuthorsDesignation and Contribution  
Shahid Ahsan; Professor: Manuscript writing and  
Final review.  
ophthalmoscopy, as high as 52% for optometrists, 45%  
for general practitioners and 33% for hospital  
physicians. These studies have suggested no or limited  
role of ―Direct ophthalmoscopy‖ in screening of DR  
so much so that even elimination of training in direct  
ophthalmoscopy for medical students has been  
Muhammad Fahadullah; Retina Specialist: Data  
collection, Final review.  
Muhammad Faisal Fahim; Statistician: Statistical  
Analysis, Manuscript writing, Final review.  
Khalida Parveen; Optometrist: Data collection, Final  
review.  
suggested21,22  
.
In present times of technology,  
Sumaira Salim; Optometrist: Data collection, Final  
ophthalmoscopy is not considered as an option, in  
spite of limited availability and cost considerations of  
Non-Mydriatic fundus photography. On the other  
hand, data are available in favor of optometrists.  
European working group in their study concluded that  
direct ophthalmoscopy through dilated pupils is the  
recommended test to screen for diabetic retinopathy,  
because it is inexpensive, efficient and rapid. In the  
opinion of this group 60% sensitivity is good enough  
for DR screening purpose and very little is gained  
from increasing the sensitivity to 80%23. In view of all  
above studies, it can be suggested that direct  
ophthalmoscopy can relied upon as cost effective  
screening tool if the optometrists are trained well and  
aware of proper referral protocols.  
review.  
Muhammad Saleh Memon; Director research:  
Manuscript writing, Final review.  
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