Journal of Clinical and Diagnostic Research, ISSN - 0973 - 709X

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Dr Mohan Z Mani

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On Sep 2018




Prof. Somashekhar Nimbalkar

"Over the last few years, we have published our research regularly in Journal of Clinical and Diagnostic Research. Having published in more than 20 high impact journals over the last five years including several high impact ones and reviewing articles for even more journals across my fields of interest, we value our published work in JCDR for their high standards in publishing scientific articles. The ease of submission, the rapid reviews in under a month, the high quality of their reviewers and keen attention to the final process of proofs and publication, ensure that there are no mistakes in the final article. We have been asked clarifications on several occasions and have been happy to provide them and it exemplifies the commitment to quality of the team at JCDR."



Prof. Somashekhar Nimbalkar
Head, Department of Pediatrics, Pramukhswami Medical College, Karamsad
Chairman, Research Group, Charutar Arogya Mandal, Karamsad
National Joint Coordinator - Advanced IAP NNF NRP Program
Ex-Member, Governing Body, National Neonatology Forum, New Delhi
Ex-President - National Neonatology Forum Gujarat State Chapter
Department of Pediatrics, Pramukhswami Medical College, Karamsad, Anand, Gujarat.
On Sep 2018




Dr. Kalyani R

"Journal of Clinical and Diagnostic Research is at present a well-known Indian originated scientific journal which started with a humble beginning. I have been associated with this journal since many years. I appreciate the Editor, Dr. Hemant Jain, for his constant effort in bringing up this journal to the present status right from the scratch. The journal is multidisciplinary. It encourages in publishing the scientific articles from postgraduates and also the beginners who start their career. At the same time the journal also caters for the high quality articles from specialty and super-specialty researchers. Hence it provides a platform for the scientist and researchers to publish. The other aspect of it is, the readers get the information regarding the most recent developments in science which can be used for teaching, research, treating patients and to some extent take preventive measures against certain diseases. The journal is contributing immensely to the society at national and international level."



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Sri Devaraj Urs Medical College
Sri Devaraj Urs Academy of Higher Education and Research , Kolar, Karnataka
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Dr. Saumya Navit

"As a peer-reviewed journal, the Journal of Clinical and Diagnostic Research provides an opportunity to researchers, scientists and budding professionals to explore the developments in the field of medicine and dentistry and their varied specialities, thus extending our view on biological diversities of living species in relation to medicine.
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Dr Saumya Navit
Professor and Head
Department of Pediatric Dentistry
Saraswati Dental College
Lucknow
On Sep 2018




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Dr. Arunava Biswas
MD, DM (Clinical Pharmacology)
Assistant Professor
Department of Pharmacology
Calcutta National Medical College & Hospital , Kolkata




Dr. C.S. Ramesh Babu
" Journal of Clinical and Diagnostic Research (JCDR) is a multi-specialty medical and dental journal publishing high quality research articles in almost all branches of medicine. The quality of printing of figures and tables is excellent and comparable to any International journal. An added advantage is nominal publication charges and monthly issue of the journal and more chances of an article being accepted for publication. Moreover being a multi-specialty journal an article concerning a particular specialty has a wider reach of readers of other related specialties also. As an author and reviewer for several years I find this Journal most suitable and highly recommend this Journal."
Best regards,
C.S. Ramesh Babu,
Associate Professor of Anatomy,
Muzaffarnagar Medical College,
Muzaffarnagar.
On Aug 2018




Dr. Arundhathi. S
"Journal of Clinical and Diagnostic Research (JCDR) is a reputed peer reviewed journal and is constantly involved in publishing high quality research articles related to medicine. Its been a great pleasure to be associated with this esteemed journal as a reviewer and as an author for a couple of years. The editorial board consists of many dedicated and reputed experts as its members and they are doing an appreciable work in guiding budding researchers. JCDR is doing a commendable job in scientific research by promoting excellent quality research & review articles and case reports & series. The reviewers provide appropriate suggestions that improve the quality of articles. I strongly recommend my fraternity to encourage JCDR by contributing their valuable research work in this widely accepted, user friendly journal. I hope my collaboration with JCDR will continue for a long time".



Dr. Arundhathi. S
MBBS, MD (Pathology),
Sanjay Gandhi institute of trauma and orthopedics,
Bengaluru.
On Aug 2018




Dr. Mamta Gupta,
"It gives me great pleasure to be associated with JCDR, since last 2-3 years. Since then I have authored, co-authored and reviewed about 25 articles in JCDR. I thank JCDR for giving me an opportunity to improve my own skills as an author and a reviewer.
It 's a multispecialty journal, publishing high quality articles. It gives a platform to the authors to publish their research work which can be available for everyone across the globe to read. The best thing about JCDR is that the full articles of all medical specialties are available as pdf/html for reading free of cost or without institutional subscription, which is not there for other journals. For those who have problem in writing manuscript or do statistical work, JCDR comes for their rescue.
The journal has a monthly publication and the articles are published quite fast. In time compared to other journals. The on-line first publication is also a great advantage and facility to review one's own articles before going to print. The response to any query and permission if required, is quite fast; this is quite commendable. I have a very good experience about seeking quick permission for quoting a photograph (Fig.) from a JCDR article for my chapter authored in an E book. I never thought it would be so easy. No hassles.
Reviewing articles is no less a pain staking process and requires in depth perception, knowledge about the topic for review. It requires time and concentration, yet I enjoy doing it. The JCDR website especially for the reviewers is quite user friendly. My suggestions for improving the journal is, more strict review process, so that only high quality articles are published. I find a a good number of articles in Obst. Gynae, hence, a new journal for this specialty titled JCDR-OG can be started. May be a bimonthly or quarterly publication to begin with. Only selected articles should find a place in it.
An yearly reward for the best article authored can also incentivize the authors. Though the process of finding the best article will be not be very easy. I do not know how reviewing process can be improved. If an article is being reviewed by two reviewers, then opinion of one can be communicated to the other or the final opinion of the editor can be communicated to the reviewer if requested for. This will help one’s reviewing skills.
My best wishes to Dr. Hemant Jain and all the editorial staff of JCDR for their untiring efforts to bring out this journal. I strongly recommend medical fraternity to publish their valuable research work in this esteemed journal, JCDR".



Dr. Mamta Gupta
Consultant
(Ex HOD Obs &Gynae, Hindu Rao Hospital and associated NDMC Medical College, Delhi)
Aug 2018




Dr. Rajendra Kumar Ghritlaharey

"I wish to thank Dr. Hemant Jain, Editor-in-Chief Journal of Clinical and Diagnostic Research (JCDR), for asking me to write up few words.
Writing is the representation of language in a textual medium i e; into the words and sentences on paper. Quality medical manuscript writing in particular, demands not only a high-quality research, but also requires accurate and concise communication of findings and conclusions, with adherence to particular journal guidelines. In medical field whether working in teaching, private, or in corporate institution, everyone wants to excel in his / her own field and get recognised by making manuscripts publication.


Authors are the souls of any journal, and deserve much respect. To publish a journal manuscripts are needed from authors. Authors have a great responsibility for producing facts of their work in terms of number and results truthfully and an individual honesty is expected from authors in this regards. Both ways its true "No authors-No manuscripts-No journals" and "No journals–No manuscripts–No authors". Reviewing a manuscript is also a very responsible and important task of any peer-reviewed journal and to be taken seriously. It needs knowledge on the subject, sincerity, honesty and determination. Although the process of reviewing a manuscript is a time consuming task butit is expected to give one's best remarks within the time frame of the journal.
Salient features of the JCDR: It is a biomedical, multidisciplinary (including all medical and dental specialities), e-journal, with wide scope and extensive author support. At the same time, a free text of manuscript is available in HTML and PDF format. There is fast growing authorship and readership with JCDR as this can be judged by the number of articles published in it i e; in Feb 2007 of its first issue, it contained 5 articles only, and now in its recent volume published in April 2011, it contained 67 manuscripts. This e-journal is fulfilling the commitments and objectives sincerely, (as stated by Editor-in-chief in his preface to first edition) i e; to encourage physicians through the internet, especially from the developing countries who witness a spectrum of disease and acquire a wealth of knowledge to publish their experiences to benefit the medical community in patients care. I also feel that many of us have work of substance, newer ideas, adequate clinical materials but poor in medical writing and hesitation to submit the work and need help. JCDR provides authors help in this regards.
Timely publication of journal: Publication of manuscripts and bringing out the issue in time is one of the positive aspects of JCDR and is possible with strong support team in terms of peer reviewers, proof reading, language check, computer operators, etc. This is one of the great reasons for authors to submit their work with JCDR. Another best part of JCDR is "Online first Publications" facilities available for the authors. This facility not only provides the prompt publications of the manuscripts but at the same time also early availability of the manuscripts for the readers.
Indexation and online availability: Indexation transforms the journal in some sense from its local ownership to the worldwide professional community and to the public.JCDR is indexed with Embase & EMbiology, Google Scholar, Index Copernicus, Chemical Abstracts Service, Journal seek Database, Indian Science Abstracts, to name few of them. Manuscriptspublished in JCDR are available on major search engines ie; google, yahoo, msn.
In the era of fast growing newer technologies, and in computer and internet friendly environment the manuscripts preparation, submission, review, revision, etc and all can be done and checked with a click from all corer of the world, at any time. Of course there is always a scope for improvement in every field and none is perfect. To progress, one needs to identify the areas of one's weakness and to strengthen them.
It is well said that "happy beginning is half done" and it fits perfectly with JCDR. It has grown considerably and I feel it has already grown up from its infancy to adolescence, achieving the status of standard online e-journal form Indian continent since its inception in Feb 2007. This had been made possible due to the efforts and the hard work put in it. The way the JCDR is improving with every new volume, with good quality original manuscripts, makes it a quality journal for readers. I must thank and congratulate Dr Hemant Jain, Editor-in-Chief JCDR and his team for their sincere efforts, dedication, and determination for making JCDR a fast growing journal.
Every one of us: authors, reviewers, editors, and publisher are responsible for enhancing the stature of the journal. I wish for a great success for JCDR."



Thanking you
With sincere regards
Dr. Rajendra Kumar Ghritlaharey, M.S., M. Ch., FAIS
Associate Professor,
Department of Paediatric Surgery, Gandhi Medical College & Associated
Kamla Nehru & Hamidia Hospitals Bhopal, Madhya Pradesh 462 001 (India)
E-mail: drrajendrak1@rediffmail.com
On May 11,2011




Dr. Shankar P.R.

"On looking back through my Gmail archives after being requested by the journal to write a short editorial about my experiences of publishing with the Journal of Clinical and Diagnostic Research (JCDR), I came across an e-mail from Dr. Hemant Jain, Editor, in March 2007, which introduced the new electronic journal. The main features of the journal which were outlined in the e-mail were extensive author support, cash rewards, the peer review process, and other salient features of the journal.
Over a span of over four years, we (I and my colleagues) have published around 25 articles in the journal. In this editorial, I plan to briefly discuss my experiences of publishing with JCDR and the strengths of the journal and to finally address the areas for improvement.
My experiences of publishing with JCDR: Overall, my experiences of publishing withJCDR have been positive. The best point about the journal is that it responds to queries from the author. This may seem to be simple and not too much to ask for, but unfortunately, many journals in the subcontinent and from many developing countries do not respond or they respond with a long delay to the queries from the authors 1. The reasons could be many, including lack of optimal secretarial and other support. Another problem with many journals is the slowness of the review process. Editorial processing and peer review can take anywhere between a year to two years with some journals. Also, some journals do not keep the contributors informed about the progress of the review process. Due to the long review process, the articles can lose their relevance and topicality. A major benefit with JCDR is the timeliness and promptness of its response. In Dr Jain's e-mail which was sent to me in 2007, before the introduction of the Pre-publishing system, he had stated that he had received my submission and that he would get back to me within seven days and he did!
Most of the manuscripts are published within 3 to 4 months of their submission if they are found to be suitable after the review process. JCDR is published bimonthly and the accepted articles were usually published in the next issue. Recently, due to the increased volume of the submissions, the review process has become slower and it ?? Section can take from 4 to 6 months for the articles to be reviewed. The journal has an extensive author support system and it has recently introduced a paid expedited review process. The journal also mentions the average time for processing the manuscript under different submission systems - regular submission and expedited review.
Strengths of the journal: The journal has an online first facility in which the accepted manuscripts may be published on the website before being included in a regular issue of the journal. This cuts down the time between their acceptance and the publication. The journal is indexed in many databases, though not in PubMed. The editorial board should now take steps to index the journal in PubMed. The journal has a system of notifying readers through e-mail when a new issue is released. Also, the articles are available in both the HTML and the PDF formats. I especially like the new and colorful page format of the journal. Also, the access statistics of the articles are available. The prepublication and the manuscript tracking system are also helpful for the authors.
Areas for improvement: In certain cases, I felt that the peer review process of the manuscripts was not up to international standards and that it should be strengthened. Also, the number of manuscripts in an issue is high and it may be difficult for readers to go through all of them. The journal can consider tightening of the peer review process and increasing the quality standards for the acceptance of the manuscripts. I faced occasional problems with the online manuscript submission (Pre-publishing) system, which have to be addressed.
Overall, the publishing process with JCDR has been smooth, quick and relatively hassle free and I can recommend other authors to consider the journal as an outlet for their work."



Dr. P. Ravi Shankar
KIST Medical College, P.O. Box 14142, Kathmandu, Nepal.
E-mail: ravi.dr.shankar@gmail.com
On April 2011
Anuradha

Dear team JCDR, I would like to thank you for the very professional and polite service provided by everyone at JCDR. While i have been in the field of writing and editing for sometime, this has been my first attempt in publishing a scientific paper.Thank you for hand-holding me through the process.


Dr. Anuradha
E-mail: anuradha2nittur@gmail.com
On Jan 2020

Important Notice

Original article / research
Year : 2021 | Month : August | Volume : 15 | Issue : 8 | Page : NC01 - NC05 Full Version

Ability of Optical Coherence Tomography in Early Detection of Primary Open Angle Glaucoma


Published: August 1, 2021 | DOI: https://doi.org/10.7860/JCDR/2021/48662.15206
Pinky Jewariya, Manish Sharma, Sandeep Parwal, Kamlesh Khilnani

1. Junior Resident, Department of Ophthalmology, SMS Medical College, Jaipur, Jhunjhunu, Rajasthan, India. 2. Professor, Department of Ophthalmology, SMS Medical College, Jaipur, Jhunjhunu, Rajasthan, India. 3. Associate Professor, Department of Ophthalmology, SMS Medical College, Jaipur, Jhunjhunu, Rajasthan, India. 4. Senior Professor, Department of Ophthalmology, SMS Medical College, Jaipur, Jhunjhunu, Rajasthan, India.

Correspondence Address :
Pinky Jewariya,
House No. 139, Ward No. 12, Adarsh Colony, Chirawa, Jhunjhunu-302026, Rajasthan, India.
E-mail: pinkyjewariya@gmail.com

Abstract

Introduction: As glaucoma is one of the leading causes of blindness, its early diagnosis is crucial. Standard Visual Field (VF) examinations are used in the diagnosis and follow-up of glaucoma, but the major drawback is that the abnormalities do not appear until 20-40% of ganglion cells are lost. Defects in the Retinal Nerve Fiber Layer (RNFL), measured by Optical Coherence Tomography (OCT), is an excellent objective and quantitative method in the diagnosis and management of glaucoma at earlier stages.

Aim: To assess the ability of OCT in diagnosing early glaucomatous changes using RNFL, Optic Nerve Head (ONH) and macular thickness parameters.

Materials and Methods: A hospital-based case control study was done for 18 months at Department of Ophthalmology, Sawai Man Singh (SMS) Hospital and Medical College, Jaipur, Rajasthan, India. Fifty patients meeting the inclusion criteria were evaluated in the study as case group. To compare the results with those of a normal population 50 age and sex matched subjects were included. Each subject underwent detailed ocular examination and RNFL, ONH and macular thickness parameters were measured using Spectral Domain (SD) OCT. The unpaired t-test was used to compare continuous variables and Chi-square test was used to compare categorical variables. The Area Under the Curve (AUC) with its 95% Confidence Interval (CI) was calculated. The p-value <0.05 was considered significant.

Results: A total of 50 glaucoma or glaucoma suspect cases and 50 controls partcipated in the present study, i.e., 100 eyes in each group were studied. Mean RNFL thickness, superior thickness, inferior thickness and temporal thickness were significantly (p<0.05) lower among cases than controls. Cup area, cup/disc (C/D) area ratio, horizontal and vertical cup to disc ratio (CDR) were significantly (p=0.0001) higher among cases than controls. Vertically Integrated Rim Area (VIRA) was significantly (p<0.05) lower among cases (0.19±0.13) than controls (0.28±0.05). There was no significant (p>0.05) difference in disc area between cases and controls. All the macular thickness parameters were significantly (p<0.05) lower among cases than controls except fovea. Overall, ONH and macular thickness parameters had high sensitivity and specificity than RNFL parameters in glaucoma patients.

Conclusion: The present study found that a combination of RNFL, ONH and macular thickness parameters improved the diagnostic accuracy of OCT in early detection of Primary Open Angle Glaucoma (POAG).

Keywords

Macular thickness, Optic nerve head, Retinal nerve fibre layer, Vertically integrated rim area

Glaucoma is one of the leading causes of blindness all over the world and reduces the RNFL thickness imaged with OCT (1),(2). Globally, glaucoma is the second most common cause of blindness after cataract. In India, glaucoma accounts for 12% of blindness and 11.4% of low vision. The prevention and treatment of glaucoma is complicated by the lack of early warnings for impending vision loss and uncertainties in the diagnosis as Primary Open Angle Glaucoma (POAG) is asymptomatic in its early stages (3).

POAG is characterised by optic neuropathy of multifactor origin with a characteristic acquired atrophy of the ONH and progressive structural loss of Retinal Ganglion Cells (RGC) and their axons developing in the presence of open anterior chamber angles, and manifests characteristic VF abnormalities, that eventually may result in vision loss and irreversible blindness (4).

Detection of structural loss plays a fundamental role in diagnosing the disease as well as management of glaucoma. While structural damage in glaucoma can be assessed subjectively by clinically examining the ONH and peripapillary RNFL, the introduction of ocular imaging modalities into clinical management has made objective and quantitative evaluation of ocular structures easier.

The OCT, first described in 1991, is a noncontact, noninvasive imaging technique that can reveal layers of the retina by looking at the interference patterns of reflected laser light (5). It is an innovative diagnostic tool in tomographic imaging of tissues. In the field of ophthalmology, its ease of access to different areas in the eye allows its use as an excellent diagnostic technology (6).

Early diagnosis of glaucoma is crucial and plays an important role in early prevention of the disease as it is the second leading cause of blindness. Standard VF examinations are used in the diagnosis and follow-up of glaucoma, but one of its drawbacks is that the abnormalities do not appear until 20-40% of ganglion cells are lost (7). Earlier defects in the RNFL measured by OCT provide an excellent objective as well as quantitative method in the diagnosis and management of glaucoma (8). The principle of low coherence interferometry used in OCT in recording the echo time delay and intensity of backscattered light from various retinal layers allow it to measure an accurate thickness of the RNFL (9).

The commercially available iteration of the OCT technology, spectral domain SD-OCT, has theoretical advantages over the earlier generation of Time Domain TD-OCT in terms of higher axial resolution power and faster speed of scanning that lead to lower susceptibility to artefacts caused by the movements of the eye. It is suggested that SD-OCT offers improved reproducibility; however, its capacity to diagnose glaucoma is statistically similar (10). The present study was a comparative type of cross-sectional study for early detection of glaucoma using OCT.

Material and Methods

A hospital-based case control study was conducted with the approval of the Institutional Ethics Committee (No.-846/MC/EC/2019) and as per the tenets of the Declaration of Helsinki at Upgraded Department of Ophthalmology, SMS Hospital and Medical College, Jaipur, India. The study was conducted for 18 months, data collection was done from July 2018 to July 2019 and another six months from August 2019 to January 2020 were taken for data and statistical analysis.

All subjects were fully informed about the nature of the study according to the codes of ethics in the Declaration of Helsinki protocol, and then written consent for participation was obtained from all the participants.

Sample size calculation: Sample size was calculated at 80% study power and α error at 0.05 assuming SD at 0.34 mm2 for VIRA as per results of seed article (11). For minimum detectable mean difference at 20 mm2 in VIRA, 45 participants in each of the two groups were required. It has been enhanced and rounded off to 50 patients as final sample size expecting 10% attrition. A total of 50 patients meeting the inclusion criteria were evaluated in the study as a case group. To compare the results with those of a normal population, 50 age and sex matched controls either from the hospital staff or patient’s attendant were included.

Inclusion criteria: Glaucoma/glaucoma suspect subjects: subjects with Intraocular Pressure (IOP) ≥21 (two consecutive readings); Open anterior chamber angle on gonioscopy; glaucomatous ONH and VF changes may be present (glaucoma subjects) or may not be present (glaucoma suspects) were included as case group in the study. Healthy subjects: Subjects with IOP ≤21 with no history of raised IOP, best corrected visual acuity more than 6/12 were included as healthy control group.

Exclusion criteria: Patients having Primary Angle-Closure Glaucoma (PACG), non-glaucomatous optic neuropathy, any associated retinal disease and having uveitis were excluded from the study.

Study Procedure

Each subject underwent detailed ocular examination including best corrected visual acuity, slit lamp examination, intra-ocular pressure measurement using Goldmann’s Applanation Tonometer (IOPGAT) and gonioscopy using three mirror gonioscopy lens and and the angle was graded using Shaffer classification (4). The VF analysis was done by Humphrey field analyser. RNFL, ONH and macular thickness parameters were measured using SD OCT (TOPCON 3D OCT) after pharmacological dilatation of the pupil with tropicamide 0.8% and phenylephrine 5%. The RNFL thickness parameters were measured at superior, inferior, nasal, temporal, 1 to 12 o’clock positions. The ONH parameters included in the study were disc area, cup area, C/D area ratio, rim area, horizontal CDR, vertical CDR and VIRA.

For macular thickness assessment 3D radial module was used; in this module according to Early treatment diabetic retinopathy study, macula was divided into nine regions with three concentric rings; the nine regions are superior outer, inferior, outer, temporal, outer nasal outer, superior and inferior inner, temporal and nasal inner and the fovea. Thickness of macula was measured at these all regions.

Statistical Analysis

The results were presented in frequencies, percentages and mean±SD. The unpaired t-test was used to compare continuous variables and chi-square test was used to compare categorical variables. The Receiving Operating Curve (ROC) analysis was carried out. The AUC with its 95% CI was calculated. The sensitivity, specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) with its 95% CI was calculated. The p-value <0.05 was considered statistically significant. All the analysis was carried out on Statistical Package for the Social Sciences (SPSS) version 16.0 (Chicago, Inc., USA).

Results

A total of 50 glaucoma/glaucoma suspect cases and 50 controls were included in the study, i.e., 100 eyes in each group. The mean age of cases and controls was 59.26±9.90 and 59.40±10.58 years respectively. (Table/Fig 1) showing comparability of the groups in terms of age.

More than half of patients of both cases (62%) and controls (70%) were males. There was no significant (p>0.05) difference in gender between the groups showing comparability of the groups in terms of gender (Table/Fig 1). IOPGAT was significantly (p=0.001) higher among cases (22.88±3.68) compared to controls (15.88±1.78) (Table/Fig 1).

In gonioscopy measurement, grade 3-4 was among more than one third of patients in both cases and controls each constituted 40%. There was no significant (p>0.05) difference in gonioscopy between the groups (Table/Fig 1).

(Table/Fig 2) shows the comparison of VFs between the groups. There was significant (p=0.001) difference in VFs between the groups.

Average thickness, superior thickness, inferior thickness and temporal thickness were significantly (p=0.0001) lower among cases than controls. Thickness was also lower among cases than controls at all the time periods (Table/Fig 3), (Table/Fig 4).

Cup area, C/D area ratio, horizontal and vertical CDR were significantly (p=0.0001) higher among cases than controls. VIRA was significantly (p=0.0001) lower among cases (0.19±0.13) than controls (0.28±0.05). There was no significant (p>0.05) difference in Disc area between cases and controls (Table/Fig 5), (Table/Fig 6), (Table/Fig 7). All the OCT-macular thickness parameters were significantly lower among cases than controls except fovea (Table/Fig 8), (Table/Fig 9).

Discussion

Glaucoma typically goes through several stages, from clinically nonapparent disease to irreversible blindness (11). The diagnosis of glaucoma can often be difficult, especially in the very early stages when structural damage and functional changes are not obvious. This has led to the development of newer diagnostic modalities to reliably diagnose the disease as early as possible.

In the present study, author evaluated the ability of OCT in differentiating between early glaucomatous and healthy eyes using RNFL, ONH, and macular thickness parameters. A total of 50 cases and 50 controls were included in the study.

In the present study, the average RNFL thickness, Superior thickness, Inferior thickness and Temporal thickness were significantly (p<0.05) lower among cases than controls. Thickness was also lower among cases than controls at all the time periods. This was in accordance with the study of Elbendary AM and Mohamed Helal R who evaluated the role of SD-OCT in different stages of glaucoma and found similar results (12). Abd El-Naby AE et al., found that patients with glaucoma had significantly lower RNFL quadrant measurements when compared with controls in microns (7). The present study is also in harmony with the study of Mansoori T et al., an Indian Asian study; who assessed the utility of SD-OCT to differentiate normal eyes from the early glaucomatous eyes (10). The study recruited 178 eyes (83 patients with glaucoma and 95 age and sex matched healthy controls). The mean RNFL thickness in healthy controls and patients with glaucoma was 105.7±5.1 and 90.7±7.5 μm, respectively (p=0.001). Additionally, Kaw SMG et al., in their study compared evaluation of RNFL thickness in normal controls and POA glaucoma of various stages by SD-OCT and found that normal patients had the higher RNFL thickness as compare to patients; moreover, increased glaucoma severity was associated with thinner RNFL (13). Moreover, the study of Firat PG et al., measured RNFL thickness in POAG, normal tension glaucoma and normal healthy individuals using SD-OCT (14). The thickness of the RNFL was found significantly higher in normal persons, followed by the normal tension glaucoma and then in POAG (p<0.05). Furthermore, the results of the present study are in accordance with the former study of Elbendary AM and Mohamed Helal R who noted in their study that normal controls had significantly higher thickness of RNFL when compared with patients having glaucoma, and those with more severe disease had significantly thinner RNFL. The findings of this study are also in agreement with the study of Golzan SM et al., who assessed RNFL thickness in patients with glaucoma and healthy controls (12),(15). In their study, glaucomatous patients had significantly lower RNFL thickness as compare to normal patients (87±26 vs. 111±15 μm p<0.0001). The present study found that RNFL thickness parameters had a mild to moderate diagnostic value for diagnosis of early glaucoma differentiating mild glaucoma from normal controls. This is in agreement with the study of Elbendary AM and Mohamed Helal R and with a meta-analysis performed by Michelessi M et al., (12),(16). The authors illustrated the accuracy of OCT for diagnosing glaucoma. They reported that RNFL had a high accuracy for diagnosing glaucoma.

In the present study, all the macular thickness parameters were significantly (p<0.05) lower among cases than controls except fovea. Chaturvedi P et al., reported that the difference was significant in superior, nasal and inferior quadrant of macular thickness paramteres (17). Khanal S et al., also found that there was a significant difference in Macular thickness asymmetry for all comparison groups (normal-NTG, p<0.05; normal-POAG, p<0.001; and NTG- POAG, p<0.001) (18). In this study, all the macular thickness parameters had good diagnostic values including AUC values for diagnosis of early glaucoma differentiating glaucoma from normal controls.

In the current study, ONH parameters such as cup area, C/D area ratio, horizontal and vertical CDR were significantly (p<0.05) higher among cases than controls. The VIRA was significantly (p<0.05) lower among cases (0.19±0.13) than controls (0.28±0.05). There was no significant (p>0.05) difference in disc area between cases and controls.

In the present study, ONH parameters like disc area <2.4 mm2 correctly predicted 30% cases with sensitivity and specificity of 60% and 58% respectively. Rim area <1.40 mm2 correctly predicted 41% cases with sensitivity and specificity of 82% and 78% respectively. Cup area >1 mm2 correctly predicted 39% cases with sensitivity and specificity of 78% and 76% respectively. The C/D area ratio >0.50 correctly predicted 34% cases with sensitivity and specificity of 68% and 84%, respectively.

Acquisition of 3D images of the ONH region enables us to accurately measure ONH parameters that include: disc and rim area, cup to disc ratio, cup volume and others. Mwanza JC et al., assessed the ability of SD-OCT to differentiate between glaucoma and age-matched healthy controls and reported that these ONH parameters are able to discriminate between healthy and glaucomatous eyes similar to RNFL thickness (19). Another study done by Sung KR et al., in patients with glaucoma, preperimetric glaucoma and healthy subjects demonstrated that thickness of the RNFL was better than any tested ONH parameter (20). The contradictory results of these two studies may be attributed due to various stages of glaucoma severity within the study samples. However, both studies reported similar diagnostic capability with rim area and average RNFL thickness in advanced glaucoma cases. The role of SD-OCT and ONH analysis in glaucoma diagnosis is yet to be determined.

In these studies, the diagnostic accuracy may not translate when used in clinical practice for diagnosis of early stage glaucoma because the discrimination studies are usually based on differentiating healthy eyes from the eyes having established glaucomatous VF loss. A SD-OCT study done by Lisboa R et al., compared the diagnostic ability of RNFL, ONH and macular parameters for diagnosing preperimetric glaucoma (21). It was an observational cohort with 13 years of follow-up and concluded that thickness of RNFL is a better parameter than ONH and macular thickness measurements for detection of preperimetric glaucomatous damage in glaucoma suspects.

Limitation(s)

Limitation of the study was small sample size which was not sufficient for the adequate results. Future studies can be done with large sample size.

Conclusion

At the end of the study, it was found that significant changes were present in RNFL thickness, macular thickness and ONH parameter in glaucoma cases as compare to healthy eyes and these changes can be easily assessed by OCT which is non-invasive technique. Also, a combination of RNFL and ONH parameters improved the diagnostic accuracy of OCT for detection of glaucoma. Using the above combination of parameters, detection of glaucoma can be done at an earlier stage and visual hazards can be prevented.

References

1.
Tham YC, Li X, Wong TY, Quigley HA, Aung T, Cheng CY, et al. Global prevalence of glaucoma and projections of glaucoma burden through 2040: A systematic review and meta-analysis. Ophthalmology. 2014;121(11):2081-90. [crossref] [PubMed]
2.
Hood DC. Improving our understanding, and detection, of glaucomatous damage: An approach based upon optical coherence tomography (OCT). Prog Retin Eye Res. 2017;57:46-75. [crossref] [PubMed]
3.
Barua N, Sitaraman C, Goel S, Chakraborti C, Mukherjee S, Parashar H. Comparison of diagnostic capability of macular ganglion cell complex and retinal nerve fiber layer among primary open angle glaucoma, ocular hypertension, and normal population using Fourier-domain optical coherence tomography and determining their functional correlation in Indian population. Indian J Ophthalmol. 2016;64(4):296-302. [crossref] [PubMed]
4.
Primary Open Angle Glaucoma; Simmons ST, Basic and Clinical Science Course: Section 10: Glaucoma, San Francisco, California: American Academy of Ophthalmology; 2005.
5.
Aref AA, Budenz DL. Spectral domain optical coherence tomography in the diagnosis and management of glaucoma. Ophthalmic Surg Lasers Imaging. 2010;41(6):S15-27. [crossref] [PubMed]
6.
Hee MR, Izatt JA, Swanson EA, Huang D, Schuman JS, Lin CP, et al. Optical coherence tomography of the human retina. Arch Ophthalmol. 1995;113(3):325-32. [crossref] [PubMed]
7.
Abd El-Naby AE, Abouelkheir HY, Al-Sharkawy HT, Mokbel TH. Correlation of retinal nerve fiber layer thickness and perimetric changes in primary open-angle glaucoma. Journal of the Egyptian Ophthalmological Society. 2018;111(1):7. [crossref]
8.
Fujimoto JG. Optical coherence tomography for ultrahigh resolution in vivo imaging. Nat Biotechnol. 2003;21(11):1361-67. [crossref] [PubMed]
9.
Morgan JE, Uchida H, Caprioli J. Retinal ganglion cell death in experimental glaucoma. Br J Ophthalmol. 2000;84(3):303-10. [crossref] [PubMed]
10.
Mansoori T, Viswanath K, Balakrishna N. Ability of spectral domain optical coherence tomography peripapillary retinal nerve fiber layer thickness measurements to identify early glaucoma. Indian J Ophthalmol. 2011;59(6):455-59. [crossref] [PubMed]
11.
Medeiros FA, Zangwill LM, Bowd C, Vessani RM, Susanna R, Jr, Weinreb RN, et al. Evaluation of retinal nerve fiber layer, optic nerve head, and macular thickness measurements for glaucoma detection using optical coherence tomography. Am J Ophthalmol. 2005;139(1):44-55. [crossref] [PubMed]
12.
Elbendary AM, Mohamed Helal R. Discriminating ability of spectral domain optical coherence tomography in different stages of glaucoma. Saudi J Ophthalmol. 2013;27(1):19-24. [crossref] [PubMed]
13.
Kaw SMG, Martinez JM, Tumbocon JA, Atienza NJ. Correlation of average RNFL thickness using the STRATUS OCT with the perimetric staging of glaucoma. Philipp J Ophthalmol. 2012;37:19-23.
14.
Firat PG, Doganay S, Demirel EE, Colak C. Comparison of ganglion cell and retinal nerve fiber layer thickness in primary open-angle glaucoma and normal tension glaucoma with spectral-domain OCT. Graefes Arch Clin Exp Ophthalmol. 2013;251(3):831-38. [crossref] [PubMed]
15.
Golzan SM, Morgan WH, Georgevsky D, Graham SL. Correlation of retinal nerve fibre layer thickness and spontaneous retinal venous pulsations in glaucoma and normal controls. PLoS One. 2015;10(6):e0128433. [crossref] [PubMed]
16.
Michelessi M, Lucenteforte E, Oddone F, Brazzelli M, Parravano M, Franchi S, et al. Optic nerve head and fibre layer imaging for diagnosing glaucoma. Cochrane Database Syst Rev. 2015;11. [crossref] [PubMed]
17.
Chaturvedi P, Chauhan A, Singh PK. An assessment of variation in macular volume and RNFL thickness in myopes using OCT and their significance for early diagnosis of primary open-angle glaucoma. Oman J Ophthalmol. 2018;11(3):241-47. [crossref] [PubMed]
18.
Khanal S, Davey PG, Racette L, Thapa M. Intraeye retinal nerve fiber layer and macular thickness asymmetry measurements for the discrimination of primary open-angle glaucoma and normal tension glaucoma. J Optom. 2016;9(2):118-25. [crossref] [PubMed]
19.
Mwanza JC, Oakley JD, Budenz DL, Anderson DR. Ability of cirrus HD-OCT optic nerve head parameters to discriminate normal from glaucomatous eyes. Ophthalmology. 2011;118(2):241-48. [crossref] [PubMed]
20.
Sung KR, Na JH, Lee Y. Glaucoma diagnostic capabilities of optic nerve head parameters as determined by Cirrus HD optical coherence tomography. J Glaucoma. 2012;21(7):498-504. [crossref] [PubMed]
21.
Lisboa R, Paranhos A Jr., Weinreb RN, Zangwill LM, Leite MT, Medeiros FA. Comparison of different spectral domain OCT scanning protocols for diagnosing preperimetric glaucoma. Invest Ophthalmol Vis Sci. 2013;54(5):3417-25. [crossref] [PubMed]

DOI and Others

10.7860/JCDR/2021/48662.15206

Date of Submission: Mar 19, 2021
Date of Peer Review: Apr 05, 2021
Date of Acceptance: Jun 11, 2021
Date of Publishing: Aug 01, 2021

AUTHOR DECLARATION:
• Financial or Other Competing Interests: None
• Was Ethics Committee Approval obtained for this study? Yes
• Was informed consent obtained from the subjects involved in the study? Yes
• For any images presented appropriate consent has been obtained from the subjects. NA

PLAGIARISM CHECKING METHODS:
• Plagiarism X-checker: Mar 20, 2021
• Manual Googling: Jun 05, 2021
• iThenticate Software: Mar 27, 2021 (24%)

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