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

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On Sep 2018




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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
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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 Academy of Higher Education and Research , Kolar, Karnataka
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Professor and Head
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Saraswati Dental College
Lucknow
On Sep 2018




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




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Best regards,
C.S. Ramesh Babu,
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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 : 2023 | Month : October | Volume : 17 | Issue : 10 | Page : NC05 - NC08 Full Version

Evaluation of Ocular Perfusion Pressure in Migraine Patients: A Case-control Study


Published: October 1, 2023 | DOI: https://doi.org/10.7860/JCDR/2023/64480.18604
S Rashmi, KS Divyalakshmi, K Soujanya, B Anupama, H Pavithra

1. Associate Professor, Department of Ophthalmology, Yenepoya Medical College and Hospital, Mangaluru, Karnataka, India. 2. Associate Professor, Department of Ophthalmology, Yenepoya Medical College and Hospital, Mangaluru, Karnataka, India. 3. Associate Professor, Department of Ophthalmology, Yenepoya Medical College and Hospital, Mangaluru, Karnataka, India. 4. Professor, Department of Ophthalmology, Yenepoya Medical College and Hospital, Mangaluru, Karnataka, India. 5. Assistant Professor, Department of Community Medicine, Yenepoya Medical College and Hospital, Mangaluru, Karnataka, India.

Correspondence Address :
Dr. KS Divyalakshmi,
203, Shakti Eminence, Shakti Nagar, Mangaluru-575016, Karnataka, India.
E-mail: divyalakshmikns2002@yahoo.com

Abstract

Introduction: Vascular dysregulation is a common underlying factor between migraine and glaucoma. Fluctuations in Ocular Perfusion Pressure (OPP) can lead to ischaemia and damage to the optic nerve head. It is unclear if the risk of glaucoma in migraine patients is due to low OPP.

Aim: To compare the OPP of migraine patients with healthy controls and assess the role of OPP as a risk factor for glaucoma in migraine patients.

Materials and Methods: This case-control study was conducted from June 2019 to May 2020 at Yenepoya Medical College Hospital, Mangaluru, Karnataka, India. Adult patients of either gender, aged between 18 and 40 years, diagnosed with migraine, were included in the study. Intraocular Pressure (IOP), blood pressure, and OPP were measured in 94 migraine patients and compared with 94 age-matched controls. Data were analysed using Statistical Package for the Social Sciences (SPSS) version 23.0. Independent t-tests were used for comparison. Adjusted odds ratios were calculated using binary logistic regression, and a p-value <0.05 was considered statistically significant.

Results: The mean IOP was 13.27±2.02 mmHg among cases and 13.38±1.87 mmHg among controls. The mean Systolic Blood Pressure (SBP) was 118.91±4.67 mmHg among cases and 116.09±5.18 mmHg among controls. The mean Diastolic Blood Pressure (DBP) was 77.72±4.48 mmHg among cases and 75.77±4.89 mmHg among controls. The mean OPP was 47.69±2.43 mmHg among cases and 46.08±2.46 mmHg among controls. The t-test values showed a statistically significant difference in SBP, DBP, and OPP between the two groups (p-value <0.05).

Conclusion: The OPP in migraine patients differed significantly from that of the controls. However, further studies are needed to evaluate the relationship between perfusion pressure abnormalities and the risk of glaucoma in migraine patients.

Keywords

Blood pressure, Glaucoma, Intraocular pressure, Ischaemia

Glaucoma, the leading cause of irreversible blindness worldwide, is a progressive optic neuropathy with a multifactorial aetiopathogenesis (1). The most significant risk factor is high IOP, and it should be reduced to halt the progression. However, optic disc damage occurs in patients with normal tension glaucoma or low tension glaucoma even when the IOP is not elevated (2). This suggests that there are mechanisms other than IOP that contribute to the occurrence and progression of glaucomatous disc damage. One such mechanism is vascular dysfunction, where there is diminished perfusion to the optic nerve head, leading to retinal ganglion cell stress and death (1).

The OPP is the perfusion pressure in the ocular vessels, calculated as the difference between blood pressure (BP) and IOP. The eye is supplied by the ophthalmic artery, in which the vessel BP is estimated to be two-thirds of the brachial arterial pressure. Therefore, OPP is defined as two-thirds of the mean arterial pressure minus IOP. Mean arterial pressure can be calculated as one-third SBP plus two-thirds DBP [2,3]. A lower OPP implies that either the IOP is high or the mean arterial BP is low. It is known that the optic nerve is vulnerable to ischaemia when the OPP is reduced. Thus, even with a normal IOP, the optic nerve is susceptible to damage, as seen in normal tension glaucoma. The vascular hypothesis suggests that abnormal perfusion to the optic nerve head is a strong factor in the pathogenesis of glaucomatous damage (2). Low OPP is an important risk factor for the development and progression of glaucoma, particularly in patients with other risk factors. This is particularly true in normal tension glaucoma, where autoregulatory dysfunctions are implicated (1),(3).

Migraine headache, a major global health issue, is a condition that involves the disturbance of the autonomic system. Vascular dysregulation is a common factor between glaucoma, migraine, and blood pressure abnormalities (4). Studies have shown that patients with migraine are at a higher risk of developing glaucoma, including Primary Open-Angle Glaucoma (POAG) and normal tension glaucoma (5),(6),(7). A possible common vascular aetiology is suggested for normal tension glaucoma and migraine (5). The exact mechanism by which migraine predisposes to glaucoma is unclear. Very few studies have investigated migraine in terms of OPP, and the evidence is inconclusive (5),(6),(7),(8). In one study, no significant difference was found in the OPP of migraine patients and controls (8).

Hence, the present study was conducted with the hypothesis that the risk of glaucoma in migraine patients is due to low OPP. The study aimed to determine whether the OPP in migraine patients differed from that of healthy controls. The primary objective was to investigate potential differences in baseline IOP, SBP, DBP, and OPP between migraine patients during pain-free periods and healthy controls. The secondary objective was to determine the changes in these parameters during migraine attacks and pain-free periods.

Material and Methods

This observational case-control study was conducted at Yenepoya Medical College Hospital, Mangaluru, Karnataka, India, from June 2019 to May 2020. Approval from the Institutional Ethics Committee (IEC) was obtained (letter number YEC 1/238/2019 dated 8/7/2019).

Inclusion criteria: Adult patients of either gender between the age group of 18 and 40 years who were diagnosed with migraine (according to the International Headache Society criteria) (9) were included in the study. They were included irrespective of whether they were on or off prophylaxis for migraine. Also, all subcategories of migraine patients were included, irrespective of whether they had migraine with aura or without aura. A total of 94 patients were included in this study.

Exclusion criteria: Patients who were already a glaucoma suspects or diagnosed with glaucoma were excluded. Hypertensive patients, pregnant women, patients with alcohol, tobacco, or any other substance (cocaine and other opioids) abuse were excluded. Patients with any other ocular or systemic diseases or previous ocular surgeries were excluded. Patients using systemic medications such as antidepressants, non-steroidal anti-inflammatory drugs, corticosteroids, immunosuppressives, bronchodilators, decongestants, phenylpropalamine, ephedrine, amphetamines, sibutramine, calcineurin inhibitors, erythropoietin, antihypertensives, oral hypoglycaemics, statins were also excluded from the study.

The purposive sampling technique was used to select the study participants from patients attending the ophthalmology outpatient department.

Sample size: The estimated global prevalence of migraine is 14.8% (10). Considering this prevalence, the sample size for the present study was calculated to be 94, using the formula:

n=Z2×p×q/e2

where n is the required sample size, ‘Z’ is the standard normal deviate (which is equal to 1.96 at a 5% significance level), ‘p’ is the prevalence, and e is the allowable error (10%).

This study included 188 participants, of which 94 were cases (patients with migraine), and the remaining 94 were age-matched healthy controls. Among the total participants, 61 (32.45%) were males, and 127 (67.55%) were females.

Methodology and Parameters Studied

The specific outcomes intended to be measured were the mean IOP, mean SBP, mean DBP, and mean OPP in migraine patients (during headache-free periods) as well as in controls.

The blood pressure was measured in the sitting position on the right arm using a manual sphygmomanometer (Welch Allyn aneroid with an adult cuff). The IOP was measured using Goldman applanation tonometry (and corrected with central corneal thickness values by pachymetry) during the daytime between 10 am to 12 noon. This narrow time window was followed to maintain uniformity among all participants and to avoid bias due to diurnal variation of IOP (11).

Then, OPP was calculated as two-thirds of the mean arterial pressure minus IOP. The right eye IOP was considered for calculation purposes. The OPP of migraine patients was compared with that of normal age-matched controls. Regardless of whether a migraine patient was experiencing a headache attack or was headache-free at the time of presenting to the outpatient department, he or she was included in the study. If the participant reported having a migraine headache at the time of presentation, this factor was noted down along with the OPP measurement. Then, the patient was requested to come on any other day, if possible, during a migraine-free period for re-evaluation of OPP.

Statistical Analysis

The data were analysed using SPSS version 23. The mean values of IOP, SBP, DBP, and OPP in migraine patients during pain-free periods were compared with healthy controls using an Independent t-test. Furthermore, adjusted odds ratios were calculated using binary logistic regression, and a p-value <0.05 was considered statistically significant. For the purpose of analysis and calculating odds ratios, the following cut-off values for healthy controls from a research study were used (12): mean IOP is more than 14.3±1.9, mean SBP is less than 118.7±9.4, mean DBP is less than 73.4±6.8, and mean OPP is less than 44.7±4.8.

Results

Among patients with migraine, the mean age was 28.34±7.5 years, with a minimum age of 18 years and a maximum of 40 years. There were 31 (33%) males and 63 (67%) females. In the control group, the mean age was 27.94±7.29 years, with a minimum age of 18 years and a maximum of 40 years. There were 30 (31.9%) males and 64 (68.1%) females. The ages of the cases and controls were matched. An independent sample t-test was conducted to determine if the ages of the two groups were similar. The ages were found to be similar, with a test statistic of 0.375 and a p-value of 0.708.

The mean values of the parameters among cases (migraine patients during a headache-free period) and controls is shown in (Table/Fig 1). There was a significant difference in SBP, DBP, and OPP between the two groups, as shown in (Table/Fig 1).

For the purpose of analysis and calculating the odds ratio, the following cut-off values from a research study were used for the healthy controls (12): mean IOP >14.3±1.9, mean SBP <118.7±9.4, mean DBP <73.4±6.8, and mean OPP <44.7±4.8. These values were considered as exposures since, according to the hypothesis, these factors in a migraine patient would increase the risk of developing ischaemia to the optic nerve head and glaucoma. In other words, the factors predisposing to glaucoma are high IOP, low SBP, low DBP, and low OPP. This is depicted in (Table/Fig 2).

There was no statistically significant association between the presence of high IOP and low DBP with the presence of migraine. However, a statistically significant association was found between the presence of low SBP and low OPP with the presence of migraine (p-value <0.05). The odds of being a migraine patient were 0.17 times higher among people exposed to OPP less than 44.6 mmHg.

Four patients underwent a second examination to compare the values during a migraine attack and a migraine-free period. However, this data was too small to draw any conclusions. The findings are shown in (Table/Fig 3). During a migraine attack, the IOP did not change. However, the DBP fell, leading to a decrease in mean BP and a subsequent reduction in OPP.

Discussion

Glaucoma is a progressive optic neuropathy characterised by disc changes and visual field abnormalities, where abnormal physiology in the optic disc interacts with the level of IOP (4). The rate and extent of disc damage depend on the IOP and the underlying abnormal physiology. In normal-tension glaucoma, this abnormal physiology makes the optic disc vulnerable to damage, even in the absence of significantly elevated IOP (4). Vascular dysregulation, including conditions such as hypertension, hypotension, migraine, and cold hands and feet, plays a role in causing disc damage in such cases (4). The aim of the present study was to investigate OPP as an IOP-independent risk factor for glaucoma, specifically normal-tension glaucoma, in patients with migraine.

The association between migraine and glaucoma is well-established, although the exact mechanism remains unclear. Migraine is significantly associated with an increased risk of open-angle glaucoma and normal-tension glaucoma (6),(13). Findings from the Blue Mountains Eye Study also suggest a possible link between migraine headaches and open-angle glaucoma (14). A higher frequency of migraine and vasospasm has been found to be associated with normal-tension glaucoma, particularly in females, and with a familial predisposition (5). A supportive relationship between migraine and glaucoma was observed, as there was a reduction in the peripapillary retinal nerve fiber layer and choroidal thickness among migraine patients compared to controls (due to chronic ischaemic insult) (15). The vascular hypothesis proposed in the pathogenesis of normal-tension glaucoma is further strengthened by the associations between multiple systemic vascular risk factors and low-tension glaucoma. These risk factors include systemic hypertension, diabetes mellitus, peripheral vascular disease, migraine headache, Raynaud syndrome, anaemia, systemic hypotension, and the use of calcium channel blockers (16).

The present study did not include hypertensive patients. However, in patients with hypertension, OPP may play a more significant role. A study found no difference in the glaucoma status of Indian subjects with or without hypertension. However, subjects on antihypertensive medications were almost twice as likely to have open-angle glaucoma. Interestingly, higher OPP was found to have a protective effect against glaucomatous disc damage. With every 1 mmHg increase in mean OPP, there was a 31% reduction in the risk of POAG (17). Another study on Indian hypertensive patients receiving antihypertensive treatment and having POAG showed lower mean OPP compared to controls (18). Although hypertensive patients had higher OPP compared to non hypertensives, they did not have a higher ocular blood flow, as measured by the pulsatile ocular blood flow tonograph. This may be due to chronic changes in vascular and haemodynamic factors in patients with hypertension (19).

A reduction in mean arterial pressure or an increase in OPP can lead to a decrease in ocular perfusion. If autoregulatory mechanisms are insufficient, then OPP may decrease due to vascular imbalances, leading to ischaemic damage of the optic nerve head. It is suggested that systemic blood pressure problems, particularly low blood pressure and low diastolic perfusion pressure, are risk factors in the pathogenesis of glaucoma. Nocturnal systemic hypotension, whether spontaneous or due to medications, has been found to increase the risk of glaucoma progression, specifically worsening of visual fields (20). Patients with normal-tension glaucoma who exhibited more peripapillary choroidal microvasculature dropout, as assessed by optical coherence tomography angiography imaging (indicating compromised optic nerve head perfusion), were found to have a greater magnitude of night time diastolic blood pressure dip on continuous ambulatory blood pressure monitoring (21). This is particularly significant in normal-tension glaucoma. In comparison to patients with POAG, patients with normal-tension glaucoma have lower mean arterial pressure (and experience more night time blood pressure dips), resulting in lower mean OPP, as shown in a South Indian study (22).

Regarding the changes occurring during a migraine attack, the present study found that during a migraine attack, IOP remains the same, while blood pressure decreases, leading to a decrease in OPP, specifically a decrease in DBP and OPP. These findings were consistent with studies that have measured blood pressure, IOP, and OPP in migraine patients (8),(11),(23). Migraine headaches are associated with neurological, gastrointestinal, and autonomic system disturbances, which can cause blood pressure changes during a migraine attack. A study conducted on normotensive migraine patients noted a reduction in blood pressure, especially DBP. Diastolic hypotension was significant just before, during, and after an acute migraine attack (23). IOP remains the same during an acute migraine attack. A study that assessed IOP in migraine patients found no significant changes in IOP during a migraine attack or pain-free period among migraine patients (8). The present study also confirmed these findings. OPP remains the same in both the migraine and control groups. A study by Michael NDB et al., also found no difference in OPP between migraine patients and controls (8). This is expected, as they did not calculate the fluctuations in OPP during migraine attacks and pain-free periods. In present study, there was also no difference in baseline OPP between migraine patients and controls. However, in the same study, the researchers noted significant thinning of the retinal nerve fiber layer in migraine patients compared to controls (8). This indicates that the moments of insult are transient, but the damage is permanent.

Limitation(s)

The mechanism underlying headaches and auras in migraine patients is still not fully understood, although changes in vessel caliber are the most common occurrence. The present study did not take into consideration whether the patients had migraine with aura or without aura, which could be a confounding factor.

Another major limitation of this study was that OPP was assessed during the pain-free period. The baseline mean OPP of migraine patients appeared to be the same as that of healthy controls, or at least not lower. Therefore, it could not be proven that low OPP in migraine patients is a risk factor leading to glaucoma. In a small subset of four patients, it was found that during a migraine attack, the OPP reduced. This suggests that fluctuations in OPP occur before, during, or after a migraine attack. Reduced OPP or fluctuations in OPP can damage the optic nerve head and contribute to glaucoma progression. However, this finding was not conclusive due to the limited sample size, and a larger prospective trial would be needed to further investigate this relationship.

Conclusion

The OPP among migraine patients differed significantly from that of the controls. However, further studies are needed to evaluate the relationship between perfusion pressure abnormalities and the risk of glaucoma in migraine patients. Considering OPP as a modifiable risk factor for glaucoma can provide opportunities for novel treatments of migraine.

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DOI and Others

DOI: 10.7860/JCDR/2023/64480.18604

Date of Submission: Apr 04, 2023
Date of Peer Review: Jun 15, 2023
Date of Acceptance: Sep 11, 2023
Date of Publishing: Oct 01, 2023

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: Apr 08, 2023
• Manual Googling: Sep 07, 2023
• iThenticate Software: Sep 09, 2023 (15%)

ETYMOLOGY: Author Origin

EMENDATIONS: 6

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