A collection of eye disorders that damage the optic nerve and impair vision can result in glaucoma, a chronic progressive optic neuropathy. After cataracts, glaucoma is the second most common cause of vision loss worldwide¹.The most frequent causative risk factor for glaucomatous optic atro- phy is elevated IOP². Three factors are taken into account in order to comprehend glaucoma: intraocular pressure, the visual field, and the cupping of the optic nerve. Glaucoma-induced blindness cannot be reversed. However, glaucoma-related blindness can be avoided, and early detection and treatment are essential. The purpose of this randomized trial is to determine the prevalence of glaucoma in patients who visit the ophthalmic outpatient department and are 40 years of age or older.

Three factors are taken into account in order to comprehend glaucoma: intraocular pressure, A randomized observational research was conducted at a tertiary care hospital's outpatient department. This study includes patients who are older than 40. An examination of the fundus, visual field, intraocular pressure, and visual acuity was conducted. They were asked about their medical and ocular issues in detail. A flashlight was used for the pupillary evaluation and external examination. Peripheral anterior chamber depth was rated using the van Herick System after slit lamp biomicroscopy was conducted⁶. Using a Schi-otz indentation tonometer, the intraocular pressure (IOP) was determined. 4% lignocaine was used to anesthetize the patient's cornea. Each eye's IOP was measured independently using a 5.5-gram weight. The table's IOP was read. All patients underwent gonioscopy utilizing a Zeiss 4 mirror goniolens in low ambient light. The Shaffer System was used to grade the angle⁷.  (I-Narrow angle) II. The angle that could be obstructive IV. Wide open angle III. Open angle IV. Pupil dilatation was performed on all participants with open angles on gonioscopy using 1% tropic amide and 5% phenylephrine. At the slit lamp, the degree of lens opacification was graded⁸.a direct ophthalmoscope was used to evaluate the optic nerve head. The ratios of cup to disc were measured and documented. Peripapillary atrophy, splinter hemorrhages, and any notching were observed. The statistical relationship was determined using Fisher's exact test.

Diagnostic criteria:

Any one of the following symptoms led to a tentative diagnosis of glaucoma suspect. IOP >=21 mmHg in either eye; focal thinning, notching, or a splinter hemorrhage; field defects on Bjerrum's tangent screen test; C:D ratio (CDR) >=0.5 in either eye or CDR asymmetries >= 0.2. When a patient with open angles on gonioscopic examination met any two of the aforementioned criteria, primary open angle glaucoma was diagnosed. Glaucomatous field defects include tubular vision (severe defect), arcuate scotomas (moderate deficiency), and paracentral scotomas (mild defect). When there are no fundus abnormalities or field defects and a pressure greater than 21 mmHg is observed, ocular hypertension is diagnosed. The best corrected visual acuity of blindness was determined to be ⁹. Current usage of anti-diabetic medicine and/or a random blood sugar level greater than 200 mg/dl, where available, were used to diagnose diabetes mellitus¹⁰. The present usage of systemic antihypertensive medication or a recorded systolic blood pressure of greater than 140 mm Hg and/or a diastolic blood pressure greater than 90 mm Hg were considered indicators of systemic hypertension. P < 0.05 was used to determine significance for each parameter.

Of the 13 patients (13.27%) with a glaucoma diagnosis, 4 (11.11%) were male and 9 (14.52%) were female. According to our study, the average age at which glaucoma develops is 64.23. It was discovered that 11 patients (11.22%) have glaucoma susceptibilities. One patient (1.02%) had primary angle closure glaucoma, six patients (6.12%) had primary open angle glaucoma, and six patients (6.12%) had secondary glaucoma.

Three (10.71%) of the 28 diabetic patients in our study had glaucoma. Ten (14.29%) of the non-diabetics had glaucoma. Four (23.53%) of the 17 (17.35%) hypertensives had glaucoma, while nine (11.11%) of the non-hypertensives had glaucoma. Of those who were myopes, there were five (14.29%) with glaucoma, and eight (12.70%) without. Four patients (30.77%) had hypertension, three patients (23.08%) had diabetes, and one patient (7.69%) had seizures as related systemic illnesses. Defective vision was the most common complaint among all 13 patients (100%) in our study. Seven patients (53.8%) reported watering and soreness.

5 patients (38.46%) patients complained of headache and colored halos. Redness was complained by 4 Pa- tients (30.77%). There were 2 (11.76%) ocular hypertensive pa- tients out of 17 hypertensives and 1 (1.23%) ocular hypertensive among the non-hypertensives.

Glaucomatous field changes were studied in all 13 patients.1 patient (7.69%) had mild field loss,5 (38.46%) had moderate field loss and 7 (53.85%) had severe field loss. 8 patients (61.54%) had IOP below 30 mmHg,2 (15.38%) had IOP between 30 and 50 mmHg and 3 (23.08%) had IOP above 50 mmHg. Patients with glaucoma in one eye was 5 (38.46%) out of 13 and 8 (61.54%) had glaucoma in both eyes. Comparing the visual field loss with duration of glaucoma,6 patients (75%) out of 8 with more than 1 year duration had tubular vision whereas in duration of less than 1 year only 1 (20%)out of 5 had tubular vi- sion.

When glaucomatous optic disc damage was assessed,1 pa- tient(7.69%) had mild damage,5 (38.46%)had moderate damage and 7 (53.85%) had advanced damage. In correlation of cup disc ratio and field, in patients with ratio less than 0.6, only 2 (40%) out of 5 had tubular vision. In patients with ratio between 0.6 and 0.8,2 patients (40%) out of 5 had tubular vision and in those with ratio more than 0.8,all 3 (100%) had tubular vision. As per the findings,8 (61.53%) among the 13 glaucoma patients were blind. Blindness in one eye was noted in 7 (53.84%) and that of both eyes was noted in 1 patient (7.69%). Among glaucoma, there were 10 patients (76.92%) with IOP > 21 mmHg and 3 (23.08%) < 21 mmHg. But in general population only 3(3.53%) had IOP >21 mmHg and 82(96.47%) had an IOP < 21mmHg.

As per the results, there is no gender predisposition to glaucoma. The reported prevalence of POAG in India ranges between 0.41% and 2.56% ^(3-5). The Vellore Eye Survey (VES) ⁽³⁾ reported a prevalence of 0.41% for POAG in the 30 to 60-year age group. The Andhra Pradesh Eye Disease Study (APEDS)⁴ noted a prevalence of 2.56% among the urban population aged more than 40 years, while the Aravind Comprehensive Eye Survey (ACES)⁵ reported a prevalence of 1.2%. In contrast, our study found the prevalence of POAG to be 6.12%, which is higher than the rates reported in previous studies. This discrepancy may be attributed to the earlier studies being population-based, whereas ours is hospital-based. In our study, no gender difference was observed in the prevalence of POAG ^(12).

The prevalence of glaucoma increased with age in our study, which aligns with the findings of earlier studies ^(4,5,11,12) (Odds ratio = 4.69, p > 0.05). In our study, diabetes mellitus, hypertension (p = 0.8), myopia, or other systemic illnesses were not associated with the development of glaucoma ^(16). However, ocular hypertension was more prevalent among hypertensive individuals (p = 0.07, Odds ratio = 10.67), indicating that hypertensive patients have a tenfold higher risk of developing ocular hypertension compared to the general population. At presentation, most patients had an intraocular pressure (IOP) of less than 30 mmHg. However, severe visual field losses were noted in those with IOP exceeding 30 mmHg, highlighting elevated IOP as a critical risk factor for glaucoma ^(2). Severe vision loss was more frequent with longer disease duration, particularly in patients with poor compliance to medication. In our study, an increasing cup-disc ratio was strongly associated with a corresponding increase in visual field loss, establishing it as an important indicator of glaucomatous damage and disease progression. Our findings confirm that glaucoma remains a growing cause of blindness in our population, underscoring the urgent need to increase awareness about this condition.Among glaucoma patients, IOP was frequently greater than 21 mmHg, whereas elevated IOP was rare in the normal population (Odds ratio = 91, p < 0.0001). This indicates a strong association between elevated IOP and the development of glaucoma.

The increased prevalence of glaucoma-related blindness indicates that the general public is not well-informed about glaucoma as a cause of blindness. All patients over 40 who present to the ophthalmology outpatient department (OPD) with complaints of vision impairment must undergo routine glaucoma screening. Every hypertensive patient who visits the ophthalmology outpatient department must also have their glaucoma risk assessed. IOP measurement, fundus examination, and visual field tests are essential in ophthalmology OPD to ensure that glaucoma is not overlooked. This will guarantee that glaucoma is detected early. Preventing blindness from glaucoma can be achieved in large part by counseling all patients for health promotion.

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