Does Gender Have an Effect in the Prevalence of Types of Glaucoma in Urban Population
Does gender have an effect in the Prevalence of types of glaucoma in urban population? Farah Akhtar1, §, Shazia Micheal2, Muhammad Imran Khan2, Sajeela yousaf 2, Muhammad Bilal3, Asifa Ahmed2, Raheel Qamar2, 4 1Al-Shifa Trust Eye Hospital Rawalpindi, Pakistan, 2Department of Biosciences, COMSATS Institute of Information Technology, Islamabad, Pakistan, 3POF Hospital, Wah Cantt, Pakistan, 4Shifa College of Medicine, Islamabad, Pakistan.
§Correspondence should be addressed to: Farah Akhtar, FCPS, DOMS, MBBS, Al-Shifa Trust Eye Hospital, Jhelum Road, Rawalpindi -46000, Pakistan.Phone: +92-3335160266 email:[email protected] com Abstract Glaucoma is the second leading cause of the blindness and epidemiologic studies of humans demonstrated significant differences between the genders in the propensity to develop various types of glaucoma. Objective: To assess the prevalence of types of glaucoma, blindness and severity with respect to gender differences. Design and Methods: Retrospective study including 3021 patients examined for types of glaucoma to determine the gender inequality in loss of vision.Data was analyzed with the statistical software SPSS. Results: It was found that overall the ratio 2.
3: 1 of males affected with glaucoma is higher then females. Males have a more prevalent POAG type of glaucoma whereas females are suffering more from PCAG glaucoma. Although the overall prevalence is higher in males but the blindness rate is greater in all types of glaucoma in females. Surgery of greater number of females is performed due to severe conditions in POAG whereas PEXG and NTG are more pronounced in males.Conclusion: Females have PCAG more prevalent while males have POAG which are the two major types. Overall the blindness rate in different types of glaucoma is high in females therefore the results of present study indicated that gender does have an effect in the prevalence and blindness due to different types of glaucoma. Introduction Glaucoma is a neurodegenerative disease of the optic nerve which occurs due to the progressive loss of optic nerve axons and death of the retinal ganglion cells (RGCs) .
It is the second leading cause of blindness affecting 70 million people worldwide and it has been estimated that the prevalence of glaucoma will be increased and the turn over of the number of cases will be 79. 6 million in the year 2020 . As glaucoma is a heterogeneous and multifactorial disease therefore it represents a number of different conditions which are responsible for the damage of the optic nerve and loss of vision associated with visual field defects and elevated intraocular pressure .In recent years the gender difference has attained much attention in the prevalence of various types of glaucoma in populations of different countries and continents. There is a requirement of fastidious consideration to gender differences in blindness for understanding of targets for blindness reduction and in the development of interventions. In different neurodegerative and blinding eye diseases it has been observed that gender have quite important targets and role in the manifestation, progression and commencement of the disease.Females have 1.
9 higher risk of developing dementia and Alzheimer’s disease by 3. 1, most of the American studies reported equal rates whereas Europeans had shown higher rates of dementia in women. Also females have increased risk of developing hypertension, hyperlipidemia, and diabetes as compared to men. It is observed that although gender differences in neurodegenerative processes are still unexplored, appears to offer great promise for the future development of better strategies for the cure of diseases and betterment of patients [4-7].In recent years it is a topic of concern in the eye diseases that do gender have any effect or not and there are different reports explaining importance of gender. Rudnicka AR et al had concluded through a Meta-analysis study of 46 studies that males have increased risk of developing primary open angle glaucoma relative to females . Similarly the impact of axial myopia, age, and retinal detachment history as risk factors for pseudophakic retinal detachment were seen predominantly in males .
Occurrence of myopia and hyperopia refractive errors, changes in pattern of astigmatism and corneal structure with age are also influenced by gender [10, 11]. The aim of the present study is therefore to determine the prevalence of various types of glaucoma, blindness due to different types of glaucoma, and positive family history with respect to gender. Materials and Methods The present retrospective study is based on the analysis of data collected after reviewing the records of the 3021 patients who had visited the glaucoma clinic of the Al-Shifa eye trust hospital Rawalpindi from August 2006-August 2009.All the data is confirmed again by the Ophthalmologist who had done the detailed examination of all the patients. The criteria for the data were based on the standard conditions of diagnosis for each type of glaucoma. The types of glaucoma which were studied include primary open angle (POAG), primary closed angle (PCAG), pseudoexfoliative (PEXG), normal tension (NTG), neovascular (NVG), steroid induced (SIG), glaucoma suspects, and the remaining types were included in the data of other types of glaucoma.The ophthalmic examination of the patients included testing for best corrected visual acuity with the help of Snellen’s chart, Goldman applanation tonometer to measure intraocular pressure (IOP), slit lamp biomicroscopy, indirect fundoscopy to determine cup-to-disc ratio (c/d), visual field defects determined with Humphrey 30–2, and gonioscopy to assess type of glaucoma.
Criteria of POAG include IOP of more than 21 mmHg, typical glaucomatous cupping of the optic disc (diffuse or focal thinning of the disc rims and cup-to-disc ratio of more than 0. ), visual field defect typical of glaucoma, an open anterior chamber angle. PCAG was defined by the same criteria as POAG except that in PCAG, a gonioscopically closed anterior chamber angle was noted. In case of PEXG, patients were evaluated by slit lamp biomicroscopy for the presence of exfoliative material along the papillary border and on the iris without dilating the eye. After pupil dilation the patients were also analyzed for the presence of white material deposits on the anterior lens surface.NTG patients were classified as having IOP in normal range but progressive optic nerve changes with open angle and visual field defects. NVG catagoried by the neovascularization on the iris, increased IOP and severe pain, and SIG by raised IOP due to the administration of steroids and glucocorticoids.
The other types of glauocma include glaucoma associated with different syndromes, secondary glaucomas and developmental, congenital, aphakic, pseudophakic, post traumatic, post vitrectomy, corneo-iridic scar, uveitic glaucoma etc.The data was analyzed to determine the overall prevalence of various types of glaucoma, with respect to the gender as well blindness caused by these types and the number of surgeries in males and females by using statistical software SPSS version 16. Results In the total three thousand twenty one patients of glaucoma the male to female ratio is 2. 3:1 which indicates that in our region males are more affected then females from glaucoma. In table 1 the overall prevalence of different types of glaucoma is represented and it is observed that POAG comprised the 40. % of the total glaucoma patients. PCAG is the second and PEXG is the 3rd prevalent type but it is shown in the table that more individuals are blind due to PCAG and NVG type of glaucoma as compared to POAG which is more prevalent.
In positive family history of glaucoma it is observed that first degree relatives of PCAG type of glaucoma have a greater chance of having glaucoma compared to other types as shown in table 1 that 15. 4 % of the PCAG patients have their relatives positive for glaucoma.The more severe conditions of glaucoma were observed in the POAG type, 32% of the patients were operated for the improvement of their vision. In table 2 the types of glaucoma were observed with respect to gender and it is observed that males have more chances of developing POAG, PEXG, NVG, SIG and traumatic glaucoma as compared to females whereas females are more prone to PCAG type of glaucoma. Although the chance of developing glaucoma are comparatively greater in males but the frequency of blindness is higher in females relative to males.When the data was analyzed with respect to surgeries it has been observed that more males were operated for PEXG and NTG glaucoma which shows more severity in males while females have more surgeries for POAG, PCAG, SIG and traumatic glaucoma as shown in table 2. Discussion Now-a- days gender differences in glaucoma is a topic of debate therefore in the present retrospective study we have observed the prevalence of types, blindness and severity of conditions with respect to gender in glaucoma.
The results of our study are in accordance to the previous studies we have observed that females are more affected from PCAG type of glaucoma while males are more effected form POAG type of glaucoma. It has been observed previously that eyes of females are on average 1mm smaller then males as well the lens and corneal curvature of females is steeper therefore their applanation tonometric readings were more then half unit higher relative to males [12-14].Most of the available studies and recent evidences have shown that females account for approximately 64. 5% of the global blindness . Recently Casson RJ et al had found in his study that female gender is associated with 9. 2 times increased risk of closed angle glaucoma as well as after each millimeter decrease in anterior chamber depth was associated with 2. 6 times greater risk of this type of glaucoma .
Similarly in a study of population of Nepal, the PCAG female patients were outnumbered then males .In other blinding eye diseases according to the survey of the Chinese Ophthalmological Society cataract the first leading cause of blindness is more common in females then males . Blindness due to trachoma was also observed two to four times at higher rate in females then males [19-21], as well recently in population of central Ethiopia gender differences were observed for blindness and low vision and they had found that Women comprised 59. % of blindness, and 70. 0% of low vision. The difference in gender distribution and low vision was statistically significant in all age groups. Women had 1.
46 excess risk of bilateral blindness . All of these studies are in agreement to our results which supports the notion that gender does have an effect in the prevalence of different types of leading eye blinding and neurodegenerative diseases.Although in all of these studies females are more blind then males but in a study of population of Iran they had found that the blindness rate was higher in males as compared to females which is in contrast to our study. We were expecting our results similar to this because both of these populations are sharing the genetic history with each other and on the basis of which they have proposed a migration route of people from Iran to Pakistan but the similar results were observed in the population of Oman which also have migration routes fromOman to Pakistan and vice versa [23- 25]. Contradictory to these results in the population of India glaucoma is not gender specific . In various studies it has been observed now that in some cases males are more effected whereas other are more prevalent in female gender, it could to due to genetic factors or due to varying expression of different receptors and hormonal difference with respect to gender.It has been observed that sex hormones have an important role in the modulation of the structural characteristics and functional activity of many ocular tissues, including meibomian gland lipid release, corneal wetting time, conjunctival goblet cell density, and intraocular pressure due to which sex related differences in eye diseases such as dry-eye syndrome, glaucoma and age related macular degeneration has been observed [27-30].
Ogueta et al had found estrogen receptor protein only in the lens epithelial cells (LECs) of female whereas Rocha et al. have seen androgen receptor protein is existed in the LECs in male only [31, 32].Therefore it is concluded that most of the eye disease are gender specific and becoming and major cause of blindness. Large numbers of experimental studies are required to confirm these results as well the hormonal and genetic mechanisms which may lead to the development of these diseases in a gender specific manner to design the new therapeutic approaches and targets for the treatment and prevention of blindness. Results Type (n)Mean Age (Years)Prevalence (% age)Blindness (%age)Positive family History (%age)Surgery (%age) POAG (1218)57. 340. 33.
812. 632 PCAG (571)57. 31910. 515. 427. 8 PEXG (348)64. 811.
53. 48. 622. 7 NTG (68)57. 12. 6. 010.
631. 8 NVG (181)58. 26. 010. 59. 428. 2 SIG (46)33.
71. 54. 31330. 4 Traumatic (66)40. 22. 00. 01.
525. 7 Glaucoma suspect (46)51. 38. 54. 69. 724 Others (265)45. 69.
03. 86. 431. 3 TypePOAGPCAGPEXGNTGNVGSIGTraumaticGlaucoma suspectOthers GenderABABABABABABABABAB Mean Age (Years)58. 255. 855. 958.
265. 163. 961. 253. 058. 956. 933.
833. 740. 839. 152. 350. 544. 647.
2 Prevalence (%age)64364060703051. 548. 560408020802060406040 Blindness (%age)2559340. 01210115. 00. 00. 00.
02. 09. 04. 04. 0 Positive family History (%age)715. 591171331861413. 5112.
00. 08. 011. 58. 04. 0 Surgery19. 53710292516.
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