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

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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.
‘Knowledge is treasure of a wise man.’ The free access of this journal provides an immense scope of learning for the both the old and the young in field of medicine and dentistry as well. The multidisciplinary nature of the journal makes it a better platform to absorb all that is being researched and developed. The publication process is systematic and professional. Online submission, publication and peer reviewing makes it a user-friendly journal.
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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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It's a honour and pride to be a part of the JCDR team. My very best wishes to JCDR and hope it will sparkle up above the sky as a high indexed journal in near future."



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




Dr. C.S. Ramesh Babu
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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 : 2022 | Month : June | Volume : 16 | Issue : 6 | Page : NC06 - NC10 Full Version

Retinal Nerve Fibre Layer and Ganglion Cell Complex Measurement and their Correlation with Visual Field Changes among Glaucoma Patients


Published: June 1, 2022 | DOI: https://doi.org/10.7860/JCDR/2022/52449.16440
Kanika Yadav, Rakesh Porwal, Praveena

1. Resident, Department of Ophthalmology, JLN Medical College, Ajmer, Rajasthan, India. 2. Professor and Head, Department of Ophthalmology, JLN Medical College, Ajmer, Rajasthan, India. 3. Assistant Professor, Department of Ophthalmology, JLN Medical College, Ajmer, Rajasthan, India.

Correspondence Address :
Dr. Praveena,
Assistant Professor, Department of Ophthalmology, JLN Medical College, Ajmer, Rajasthan, India.
E-mail: tandon.praveena@gmail.com

Abstract

Introduction: Glaucoma is an optic neuropathy that causes loss of Retinal Ganglion Cell (RGC) and changes in the visual field. The loss in RCG is determined by Optical Coherence Tomography (OCT), and visual field defects are evaluated with perimetry. A study of RGC loss and visual field defects together might help to detect glaucoma earlier.

Aim: To determine the relationship between Retinal Nerve Fibre Layer and Ganglion Cell Complex (RNFL-GCC) thickness measured with OCT, and visual field sensitivity evaluated with Standard Automated Perimetry (SAP) in glaucoma patients of varying severity.

Materials and Methods: This was a cross-sectional study, conducted in a tertiary care Hospital, Ajmer, Rajasthan from October 2018 to January 2020. Ethics committee clearance was obtained prior to the study. Sixty glaucoma patients were recruited for ophthalmic evaluation. The two test were preformed SAP and SD-OCT were done on all patients. Patients were categorised into three groups i.e., early, moderate and severe, based on severity. The RNFL, Mean Deviation (MD) and Pattern Standard Deviation (PSD) were compared among these three groups. One way ANOVA was used to compare the mean values of RNFL, GCC, MD and PSD across the three glaucoma groups. Post hoc analysis was done by Tukey’s range test. Correlation was assessed using Spearman’s correlation coefficient.

Results: The mean (SD) age of participants were 54.43 (10.07) years. About 15% of patients belonged to early stage glaucoma, 40% to moderate and 45% to severe glaucoma. The difference in mean RNFL (both superior and inferior) was found significant among the three groups. In bivariate analysis, MD was found significantly correlated with superior and inferior RNFL (r=0.70, p<0.01 and r=0.47, p<0.01, respectively). The MD was not found to correlate with superior and inferior GCC whereas, PSD was found weakly correlated with GCC superior and inferior (r=-0.26, p=0.04 and r=-0.27, p=0.03, respectively), though there was inverse correlation with both GCC superior and GCC inferior. PSD was not found to correlate with superior and inferior RNFL.

Conclusion: Superior and inferior RFNL were associated with MD, an indicator of the severity of glaucoma. The RNFL thickness was the best indicator to differentiate the severity of glaucoma. Further exploration is needed to develop specific indications of RNFL and GCC measurement in the management of glaucoma.

Keywords

Optical coherence tomography, Optic neuropathy, Perimetry, Retinal ganglion cell

Glaucoma is an optic neuropathy that causes loss of RGC and changes in visual field (1). It is one of the leading causes of blindness (2). Diagnosis of glaucoma is based on the classical triad of elevated Intraocular Pressure (IOP), glaucomatous optic atrophy or cupping, and visual field loss (3). However, the progression of glaucoma is monitored by visual field defect evaluation (1),(4). SAP is the gold standard for visual field testing (5). However, functional defects are revealed after significant structural damage, and compliance to SAP depends on patient attention levels (1),(4),(6).

Evaluation of structure and function together might help to detect glaucoma earlier. RNFL imaging and GCC imaging from OCT has been found useful to detect and monitor glaucomatous changes in various studies (1),(4),(5),(6),(7),(8),(9),(10),(11),(12). Their relation with perimetry parameters has been studied over the last few years (1),(4),(5),(6),(7),(8),(9),(10),(11),(12).

Localised or diffused thinning of RNFL represents the loss of RGCs of varying degrees. It is determined by OCT, which distinguishes normal eyes from glaucomatous eyes. Macular Ganglion Cell Complex (GCC) is also known to be affected in glaucoma. Glaucoma targets the cells in the area of their highest concentration i.e., GCC. The relevance of GCC thickness to diagnosing glaucoma was studied by many researchers (4),(6),(8),(9),(12).

In glaucoma, structural changes precede loss of visual function. Therefore, it is important to study the structural and functional changes together to detect glaucoma at its various stages. There are limited studies available from India which has studied the structural and functional changes together to detect glaucoma. So, the present study aimed to determine the relationship between visual field sensitivity evaluated with SAP and RNFL-GCC thickness measured with OCT in glaucoma patients of varying severity.

Material and Methods

It was a cross-sectional study, conducted in the Department of Ophthalmology in JLN Medical College in central Rajasthan from October 2018 to January 2020 with the purposive sampling technique, sixty glaucoma patients were recruited for the study. The study plan was approved by the Institutional Review Board of JLN Medical College, Ajmer, Rajasthan. (No. 979/2019). The study followed all the tenets of the declaration of Helsinki. Written informed consent was obtained from each participant before data collection.

Inclusion criteria: Patients older than 40 years, Best Corrected Visual Acuity (BCVA) at least finger count from six meters, glaucomatous optic neuropathy, good corneal clarity, no significant cataract, and pupil diameter greater than 3 mm were included in the study.

Exclusion criteria: Subjects with evidence of any anterior segment pathology, any lens pathology, congenital glaucoma, history of any other known systemic or ocular disease, and patients with unreliable visual fields defined as false-negative >33%, false-positive >33%, and fixation errors >20% were excluded from the study.

Each participant underwent ophthalmic evaluation, visual acuity testing, IOP, slit lamp biomicroscopy, ophthalmoscopy, visual field testing and OCT.

Study Procedure

Distant and near visual acuity was assessed by Snellen’s Chart (13). Refraction was done with an auto refractometer. The IOP was taken with goldmann applanation tonometer and values were presented in mm of Hg. Anterior segment was evaluated with slit lamp bio microscopy. Angle was assessed by gonioscopy. Fundus was evaluated with direct and indirect ophthalmoscope.

Visual field was examined with automated perimetry using Swedish Interactive Thresholding Algorithm (SITA) Standard 30-2 perimetry. The criteria to define glaucomatous defect were, a threshold sensitivity loss of two or more contiguous test locations on the pattern deviation plot with p<0.01, three or more such contiguous test locations with p<0.05 with at least one of the points depressed to p<0.01, or a 10 dB difference across the nasal horizontal midline at two or more test locations (14). Humphrey global parameters, MD and PSD were used for comparison and correlation (15).

Optic disc changes were evaluated with Spectral domain OCT. RNFL thickness was assessed by Optic Nerve Head (ONH) mode with a 3.45 mm diameter around the optic disc.

The GCC was assessed with a focus of 1 mm temporal to the fovea and a square grid (7×7 mm) on the central macula. Superior and inferior GCC thicknesses were calculated. The pupil size of each subject was assessed under ambient conditions before the scan. Those with a diameter of less than 4 mm were dilated with 0.5% tropicamide.

Patients were categorised into three groups i.e., early, moderate and severe, based on severity according to Hodapp, Parrish and Anderson classification (16).

Statistical Analysis

Statistical analysis was done using Statistical Package for Social Sciences (SPSS) version 20.0. Categorical variables such as gender and type of glaucoma were presented as proportion, and continuous variables such as age, RNFL/GCC thickness, MD, PSD were presented as mean (SD). Bivariate correlation between RNFL/GCC thickness and visual field indices (MD and PSD) were assessed with Spearman’s correlation coefficient. The mean values of RNFL, GCC, MD and PSD were compared using One way ANOVA. Post hoc analysis was done by Tukey’s range test. Receiver Operating Characteristic (ROC) curves were used to assess the accuracy of RNFL and GCC thickness to diagnose glaucoma. The p <0.05 was considered statistically significant for all statistical analyses.

Results

A total of 67 subjects were recruited for the study, out of those, seven were excluded due to poor OCT imaging. Sixty patients were included to determine the relationship between RNFL/GCC thickness and visual field sensitivities.

The mean (SD) age of participants were 54.43 (10.07) years. Out of sixty participants forty were male and twenty were female. The participants had 25%, 48.33% and 26.67% open, narrow and close angle glaucoma respectively. The mean (SD) IOP in the study sample was 23.12 (4.01) mmHg. The mean (SD) RNFL thickness for superior and inferior region were 81.35 (26.97) um and 78.15 (29.6) um respectively. Average superior and inferior GCC thickness were found 80.27 (30.98) um and 77.07 (32.03) um respectively. The mean (SD) MD and PSD were found to be -14.23 (7.73) dB and 7.77 (2.77) dB, respectively (Table/Fig 1).

About 15% (n=9) of patients belonged to early stage glaucoma, 40% (n=24) to moderate and 45% (n=27) to severe glaucoma. The difference in mean RNFL (both superior and inferior) was found significant among the three groups. On post hoc analysis, a significant difference in RNFL superior was found between early and severe, and between moderate and severe. Mean of RNFL inferior was found significantly different between moderate and severe glaucoma in post hoc analysis. Mean of MD and PSD were also found significantly different among the three groups. In the post hoc analysis, this difference was observed across the groups (Table/Fig 2), (Table/Fig 3).

In bivariate analysis, MD was found significantly correlated with superior and inferior RNFL (r=0.70, p<0.01 and r=0.47, p<0.01 respectively). The MD was not found correlated with superior and inferior GCC. The PSD was found weakly correlated with GCC superior and inferior (r=-0.26, p=0.04 and r=-0.27, p=0.03, respectively). Since there was a negative correlation, it is inferred that as the glaucoma advances GCC decreases and PSD increases. The PSD was not found correlated with superior and inferior RNFL (Table/Fig 4), (Table/Fig 5), (Table/Fig 6).

To assess a differentiation based on RNFL and GCC, ROC curves were generated with various sensitivities at fixed specificity. Results are shown in (Table/Fig 7), (Table/Fig 8). The Area Under the Receiver Operating Characteristic Curve (AUROC) were found 0.839 and 0.687 for RNFL superior and inferior respectively to differentiate severe glaucoma from other types of glaucoma. It was observed 0.745 and 0.505 for RNFL superior and inferior respectively to differentiate moderate glaucoma from early glaucoma. The AUROC of GCC superior and inferior were found 0.585 and 0.575 respectively to differentiate severe glaucoma, and 0.616 and 0.653, respectively to differentiate moderate glaucoma from early glaucoma (Table/Fig 7), (Table/Fig 8).

Discussion

Detection of glaucomatous changes is usually done by observing structures (RNFL and GCC) affected by glaucoma and by assessing visual function using perimetry. It is crucial to understand the link between structural and functional glaucoma changes. In this study, we observed structure (RNFL and GCC) and visual function (MD and PSD) of 60 glaucoma patients. The SAP points were converted to a linear scale before calculating the correlation, as RNFL and GCC values were also collected in linear scale (in microns).

It was found that the thickness of the RNFL and the thickness of the GCC had different structure function relationship with visual field sensitivity and varied diagnostic values to identify glaucoma severity in the current study. The RNFL and GCC thickness, on the other hand, had the same structure function relationship with VF sensitivity and diagnostic values for glaucoma detection, according to Kim NR et al., (4). In the present study, RNFL (Superior and inferior) thickness was found significantly different in three glaucoma groups. Similar findings were reported by Kim NR et al., (4). The GCC thickness was not found significantly different in three glaucoma groups. It was not consistent with the study done by Kim NR et al., in which GCC was found better predictor to differentiate the severity of glaucoma (4). The present study was in agreement with other studies, in which RNFL was found as a better predictor than GCC (10),(11),(12).

When compared to GCC thickness, RNFL thickness was found to be a superior diagnostic sign for glaucoma, and the AUROC difference was similarly in line. We found distinct AUROC outcomes for glaucoma distinguishing between RNFL and GCC thickness in the current study. The diagnostic value of RNFL and GCC measures has been evaluated in a few studies, and the results have demonstrated that GCC diagnosis is comparable to RNFL diagnosis (8),(9).

So, more research on the relevance of mean GCC thickness in the diagnosis of early glaucoma is needed. The RNFL thickness also showed a relationship with severity of disease, whereas GCC thickness didn’t show any relationship. Other studies had shown role of both RNFL and GCC in the severity of the disease (1),(4),(6),(10). This could be due to the fact that only about half of the RGC are found in the macula, whereas virtually all of the RGC are examined in a peripapillary OCT RNFL scan (4). Because glaucoma is a diffuse illness, the ability to assess damage throughout the eye may provide RNFL assessment an edge with GCC thickness evaluation in identifying glaucoma. Moreover, RGCs measurement at the periphery revealed greater absolute thickness changes than at the macula (4). Another major advantage of RNFL over macular GCC thickness assessment is that it is not affected by non glaucomatous macular pathology. Diabetes and macular degeneration, for example, have a direct effect on macular thickness and may restrict or accentuate the findings seen with glaucoma. Such major issues were not observed in the RNFL evaluation (4),(8).

Though, the glaucomatous changes often occur initially in the inferior pole and that change associated with glaucoma usually manifests first in the superior visual field, corresponding to abnormalities in the inferior pole (1),(7),(8). The present study showed that the superior RNFL was the most strongly associated parameter with glaucoma status because it had mostly moderate and severe glaucoma patients.

The thickness of the RNFL as evaluated by OCT was shown to be correlated with visual field parameters like MD in the present study. The RNFL loss can occur without any change in the visual field in early stage glaucoma and is better diagnosed by OCT whereas, in advanced stages, visual field variations may be used to detect the progression of glaucomatous damage since the variation in RNFL thickness is too tiny to detect and the changes in the visual field is larger and easier to notice (1). The PSD is also thought to be a more accurate indicator of localised changes in the visual field, and it has been shown to duplicate a good correlation with glaucoma in thinner portions of the papillary rim (1),(12),(17).

Though, in current study it was found that RNFL thickness had a higher sensitivity than GCC thickness in differentiating glaucoma severity. But, macular GCC thickness also has a significant role in the detection of glaucoma (1),(6),(8),(12). New algorithms for the specific indication of RNFL and GCC measure, in combination or alone, should be developed. The relevance and benefits of RNFL and GCC thickness assessment in glaucoma is relatively a novel approach and should be further amplified for the evaluation and management of the disease.

Limitation(s)

The study had few limitations, including small sample size. The longitudinal link between structural and functional factors could not be determined in this cross-sectional study. Although the linear correlation was found, the spatial distribution of structural characteristics for the changes in functional loss was not investigated. The present study excluded controls and the full spectrum of glaucomatous damage including suspected glaucoma. The precision of the RNFL and GCC thickness was not assessed, which could alter diagnostic abilities depending on glaucoma severity. The role of RNFL and GCC in glaucoma management should be further explored and specific indications, in combination or alone should be developed.

Conclusion

The optic disc findings on SD-OCT were correlated with visual field parameters in glaucoma patients. Superior and inferior RFNL was strongly correlated with MD. The RNFL thickness can differentiate the severity of glaucoma in early glaucoma patients. These parameters should be used together to improve our understanding of glaucomatous changes.

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DOI and Others

DOI: 10.7860/JCDR/2022/52449.16440

Date of Submission: Oct 07, 2021
Date of Peer Review: Jan 09, 2022
Date of Acceptance: Mar 03, 2022
Date of Publishing: Jun 01, 2022

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

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