European Journal of Cardiovascular Medicine

Glaucoma is a collection of eye diseases that affect the optic nerve, which is essential for proper vision. An unusually high pressure in the eye is often the source of this injury. 1 Glaucoma is derived from the Ancient Greek term glaukos, which means "shimmering”. 2 Glaucoma has been dubbed the "silent thief of sight" because the loss of eyesight normally happens gradually over time. 3 Glaucoma is the second leading cause of blindness in the world. 4 It is a serious worldwide problem that causes severe ocular morbidity and impairment as a consequence of its progressive nature, which results in permanent vision loss. 5 Open-angle glaucoma, angle-closure glaucoma, Normal-Tension Glaucoma, and Congenital Glaucoma are the four kinds of glaucoma. Open-angle and angle- closure are the two most common forms.

An rise in intraocular pressure (IOP), or pressure within the eye, characterizes certain conditions. Secondary Glaucoma, Pigmentary Glaucoma, Pseudoexfoliative Glaucoma, Traumatic Glaucoma, Neovascular Glaucoma, Irido Corneal Endothelial Syndrome, and Uveitic Glaucoma are some of the other kinds of glaucoma. 6 Primary open-angle glaucoma (POAG) is the most frequent type of glaucoma. 7 POAG is a multifactorial optic neuropathy characterized by atrophic alterations in the optic nerve and accompanying visual field defects. 8 POAG is often detected during regular eye examinations and is usually detected only when the illness is advanced. It mostly shows as peripheral visual field loss, with central vision remaining practically intact until the later stages.

Significant visual field loss has generally happened by the time the patient is symptomatic and the condition is recognized, and the vision loss is irreversible. 9 High intraocular pressure, familial history, corticosteroid sensitivity, myopia, African-American ethnicity, systemic high blood pressure, diabetes, and age are all risk factors for POAG. In addition to these risk factors, a poor prognosis is linked to early start of illness, poor adherence to a medication regimen, and few physician visits. 10 Hypertension is a long-term medical disorder characterized by chronically high blood pressure in the arteries. 11 Hypertension is seldom accompanied by symptoms, and it is generally detected via screening or while seeking medical attention for something unrelated. Headaches (especially at the back of the head and in the morning) are common symptoms of high blood pressure, as are lightheadedness, vertigo, tinnitus (ringing or hissing in the ears), distorted vision, and fainting spells. 12 Hypertension may be related with abnormalities in the ocular fundus observed by ophthalmoscopy on physical examination. 13 Systemic hypertensions, among vascular variables, may contribute to elevations in IOP by aqueous humor overproduction or impeded outflow. 14 There has yet to be demonstrated a direct and obvious link between glaucomatous damage and blood pressure levels. 15 This link has been explained by a number of methods. Hypertension may affect blood flow to the front optic nerve by causing direct microvascular injury. 16 Hypertension may also impede autoregulation of the posterior ciliary circulation. 17.

This is a prospective and observational study was conducted in the Department of Ophthalmology at Santosh Medical College & Hospital, Ghaziabad from November 2015 to December 2016. Total 74 (the study subjects was reduced from 100 to 74). All patients with systemic hypertension attending OPD of Ophthalmology were considered as study subjects.

 Inclusion criteria:

1. Patients with documented systemic hypertension on antihypertensive medications
2. Patients above 40 yrs of age of all genders.
3. Study subjects willing & gave their consent to participate in study.

 Exclusion criteria:

1. Patients less than 40 years of age.
2. Patients with secondary glaucoma.
3. Patients with diabetes and patients with family history of glaucoma.
4. Corneal scarring/ opacity on which gonioscopy is not helpful.
5. Previous ocular trauma or diseases other than primary open angle glaucoma.
6. Patients with inflammatory arterial diseases.
7. Patients with renal disease
8. Systemic vascular disease
9. Myopia Study subjects not willing to participate & not gave consent.

Method of data Collection:

Data was collected from patients of primary open angle glaucoma with systemic hypertension presenting to ophthalmology department. Patients with systemic hypertension meeting the criteria mentioned above were included in the study after taking informed consent. A detailed history regarding past medical illness including hypertension, duration of hypertension, family history of glaucoma was taken. Details regarding antihypertensive medications and any other medications that the patient was on were also obtained.

Case definitions:

Systemic Hypertension was defined by documented diagnosed case of hypertension with a blood pressure of >140/90 mmHg and on treatment with anti hypertensive medications. Primary open angle glaucoma was defined by the presence of open angles in gonioscopy with any two of the following features; IOP >21 mm Hg. Glaucomatous optic disc changes.

Visual field changes suggestive of glaucoma.

Each patient is subjected to a detailed history taking followed by detailed ocular examination. Patients will be advised to get admitted to hospital for observation and better follow-up .if not ,they are advised to attend follow-up in OPD without fail.

1. Systemic Blood Pressure recorded by using digital sphygmomanometer with average of 3 readings at an interval of 10 min in right upper limb in sitting position. Recording of Visual Acuity was assessed using Snellen’s chart.
2. Gonioscopy was done with Goldmann’s goniolens
3. IOP measured using Goldmann’s applanation tonometer
4. Visual fields assessment by Humphrey perimetry

      Pachymetry for Central Corneal Thickness.

Statistical Analysis: Microsoft Excel 2016 was used to enter data, create charts and graphs, and so on. SPSS V 23 was used to analyze the data (trial version). Chi-square tests were used to analyze qualitative data, while t-tests, z-tests, and other statistical tests were used to analyze quantitative data. A p-value of less than 0.05 was deemed statistically significant. Charts, tables, and graphs were used to show the findings.

TABLE 1: Showing gender wise distribution of study subjects

Table 1 depicts that, among study participants, about 66 % were males & 34% were females

Table 2: IOP reading wise distribution of study subjects.

Table 2 demonstrating that out of 74 patients, 31 patients i.e., 42% had high IOP & remaining 58% had normal IOP.

Table 3 Showing Mean & Median values of IOP in right eye & left eye

Table 3 depicts that the mean values of IOP in right & left eyes were 21 mm of Hg & 20.80 mm of Hg respectively; clearly showing that mean IOP is slightly higher in Right eye of patients. Median values were 21 for right eye & 20.50 for left eye. Standard deviation for right eye was 3.664 & left eye was 3.188. Maximum value for right eye was 34 & minimum was 14 and for left eye maximum & minimum values were 30 & 14 respectively.

Table 4: Showing the mean & median for Central Corneal Thickness in Right eye & Left eyes.

Table 5 showing that mean value for Central Corneal Thickness in Right eye as 511.36 with a standard deviation of 15.431 & median lies at 510. Maximum value was 555 & minimum was 480. Whereas in left eye, mean value for Central Corneal Thickness was 511.15 with a standard deviation of 13.918. Maximum & minimum values were 550 & 480 respectively

Table 6: Showing the mean & median for Vertical CDR in Right eye & Left eye

Table 6 showing that mean values for vertical cup disc ratio in right & left eyes as 0.535 & 0.537 respectively with standard deviation in Right eye was 0.1648 & in left eye was 0.1767. Median value lies at 0.5 in both eyes with Maximum & minimum values in right eye at 0.9 & 0.3 respectively and in left eye maximum was 0.9 & minimum was 0.3.

Table 7: Showing the gonioscopy findings according to Shaffer’s grading in study subjects

Table 7 depicts that majority of study participants i.e., 89.2% had Grade III under Shaffer’s grading for glaucoma as Gonioscopy finding & only 10.8% had Grade IV as per Shaffer’s grading.

In this study, 31 patients i.e., 42% had high IOP (>21 mm of Hg) & remaining 58% had normal IOP (<21 mm of Hg). Mean IOP was 21.68+3.822 mmHg. In a study conducted by Afekhide E. Omoti et al18 in Nigeria had found out that, the mean IOP in the was 22.65+11.06 mmHg. In a research study conducted by Kim K E in Korea reported that, the mean IOP among systemic hypertension cases was 14.4+2.9 mmHg. In a study conducted by AO Onakoya in Nigeria found that, among hypertensives, lOP> 21mmHg was found to be 18.7% & the mean IOP was 28.45±10.3 mmHg.  In a study conducted by Zheng Y in Singapore in 2006 (the Singapore Malay eye study) reported that among individuals with Open Angle Glaucoma the mean IOP was 16.8 + 5.9 mmHg.

The mean IOP in current study is different when compared to studies mentioned above except with study conducted by Afekhide E. Omoti et al18 Relatively similar findings was seen in a study by Afekhide E. Omoti et al. 18 Mean IOP was relatively higher compared to studies of Zheng Y whereas, mean IOP was relatively lower compared to study conducted by AO Onakoya . These variations, might be due to the difference in sample size, study area & other patient factors. In the current study, Intra Ocular Pressure was found positively correlated with Systolic Blood Pressure & Diastolic Blood Pressure and statistically significant associations were found with SBP & DBP.

In a study conducted by Bonomi  reported that, Intraocular pressure correlates with blood pressure & the correlation is statistically significant (p<0.001) for both systolic and diastolic pressure. In a study conducted by Ganagi S M  found that IOP is correlated with both SBP & DBP. In research by Gore V stated that, there is positive correlation between IOP and SBP, DBP. Klein et al, in Beaver dam eye study said that, there was significant direct correlations between changes in systemic blood pressures and changes in intraocular pressure. In a study conducted by Sandhya.R, found that, both Systolic and Diastolic blood pressures was significantly associated with IOP.

In present study, mean values for SPP, DPP & MOPP were 119.12; 65.18 & 48.23 respectively. SPP, DPP & MOPP were having statistical significant associations with IOP. In a study conducted by Zheng Y mean, MOPP, SPP, and DPP were 51.6 +10.2, 134.5 + 24.6, and 61.4 + 11.5 mm Hg, respectively & they also found that OAG risk was significantly higher in participants with DBP, MOPP, or DPP. In a study conducted by Fijo Kuriakose,  IOP was found to be significantly associated with mean ocular perfusion pressure. In a study conducted by Afekhide E. Omoti et al18 they reported that, systolic perfusion pressure was significantly higher in glaucoma patients. There was no significant difference in diastolic perfusion pressure, mean perfusion pressure and pulse rate between glaucoma patients and control. In this study, mean value for Central Corneal Thickness in Right eye as 511.36 μm with a standard deviation of 15.431.

Whereas in left eye, mean value for Central Corneal Thickness was 511.15 μm with a standard deviation of 13.918. In the current study, there was a statistically significant association was seen between CCT & IOP in both eyes. In a study conducted by Shah S, Chatterjee A, et al mean CCT was 550.1 μm in the POAG eyes. In a study conducted by, Foster et al highly significant positive correlation was identified between IOP and CCT. Among 74 study participants 31 cases were suffering from BOAG, i.e 62 eyes having OAG .Were as 15 individuals were diagnosed as UOAG i.e 15 eyes having OAG. When all the OAG affected eyes were added (31BOAG,15UOAG) a total of 77 eyes were found to be having Open angle glaucoma.

Even though, many studies reported that higher systemic blood pressure is having higher risk of developing POAG & few studies reported that hypotension is also a risk factor for developing POAG. But, in the current study there was a statistically significant association found between Systemic hypertension & POAG and also IOP is positively correlated with SBP. Thus, with this study, it can be concluded that systemic hypertension is one of the risk factors for developing POAG.

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