FP1465 : Prevalence of Glaucoma in Patients Referred for Cataract Surgery : is It the Tip of Iceberg

Dr. Bhavya Mehta, Dr. (Col) Madhu Bhaduria, Dr. Sachin Mantawar, Dr. Arjun Bamel, Dr.Vijay Pratap Singh Tomar

Prevalence of Glaucoma in Patients referred for

Cataract Surgery: is it the tip of the iceberg

Vijay Pratap Singh Tomar, Madhu Bhadauria, Bhavya Mehta, Arjun Bamel, Sachin Mantawar

cataract and glaucoma are frequently coexisting ocular conditions in the elderly population. Both can be a natural part of the aging process. Many people over 60 may have both of these serious sight threatening conditions. Glaucoma is responsible for significant ocular morbidity in India. Primary glaucoma accounts for 2/3rds of the morbidity.1 A significant portion of those who had undergone cataract surgery from rural cohort of Chennai glaucoma study had glaucoma.2 There is a growing acceptance that the prevalence and predominant type of glaucoma show racial variability. Population-based surveys in the age group 40 years and older in different races have shown large variations. Since rural India is comparatively underserved in terms of both availability and quality of ophthalmic care it is possible that the reported rate of glaucoma is an exaggeration.3 We report our data on prevalence of glaucoma in patients referred for cataract surgery from rural screening camps.

 Materials and Methods

A retrospective review was conducted of all patients diagnosed with cataract and referred from rural cataract screening camp for cataract surgery to Sitapur eye hospital. The medical records of 5024 consecutive patients referred for cataract surgery in the month of January & February 2016  were reviewed. The following variables were collected: detailed history, demographics, detailed slit lamp examinations, ocular co morbidity, intraocular pressures, fundus examination, 90D examination, and   gonioscopy, visual fields and ocular treatments.

External examination and pupillary evaluation were done using a torchlight. Slit Lamp biomicroscopy was done and any abnormalities in the anterior segment were noted. Using a narrow slit beam, peripheral anterior chamber depth was graded according to van Herick’s technique. Intraocular pressure (IOP) was recorded with a rebound tonometer (icare) The righteye was measured first and one reliable measurement was recorded for each eye. Gonioscopy was performed  , in dim ambient il lumination with a shortened slit that did not fall on the pupil. A 4-mirror Posner lens was used. The angle was graded according to the Shaffer system and the peripheral iris contour, the degree of trabecular meshwork pigmentation, and other angle abnormalities were recorded. An angle was considered occludable if the pigmented trabecular meshwork was not visible in more than 180° of the angle in dim illumination (primary angle closure suspects [PACS]). If the angle was occludable, indentation gonioscopy was performed and the presence or absence of peripheral anterior synechiae was recorded.

All subjects with open angles on gonioscopy underwent pupillary dilation using 1% tropicamide and 5% phenylephrine hydrochloride (Unimed Technologies, Halol, Gujarat, India). Subjects diagnosed as having PACS underwent pupillary dilatation after laser iridotomy.

Stereoscopic evaluation of the optic nerve head was performed using a 90 diopter (D) lens at slit lamp. The vertical and horizontal cup-disc ratios (CDRs)  were measured and recorded. Presence of any notching, splinter haemorrhages, and peripapillary atrophy was documented. The detailed retinal examination was done with binocular indirect ophthalmoscope using the 20-D lens. Information was analysed.

Results

A total of 5024 subjects were examined (2662 men 52.98%, 2361 women 46.99%). The mean age was between 40-70 years. The mean IOP by rebound tonometer was 14.42 +/- 2.89 mmHg. 

Primary Open Angle Glaucoma

There were 125 subjects (2.25%) ). The mean age was between 61 to 70 years. The mean IOP values were 23.53 +/- 5.4 mm Hg. Mean CCT value= 530 +/- 5microns

 Primary Angle-Closure Glaucoma

There were 53 subjects (0.99%).Mean age was between 60 to 70 years. The mean IOP values were 29.70 +/- 15.6 mm Hg. Mean CCT value= 542+/- 5 microns

 Glaucoma Suspects

There were 60  glaucoma suspects. Out of which 11 (0.22%) subject had ocular hypertension, 14(0.28%) was diagnosed as NTG, 35 (0.61%) were disc suspects. Mean CCT value OHT= 550 +/-5 microns Mean CCT value NTG= 540+/- 5 microns Mean CCT value in disc suspects was 530+/- 5 microns.  

Secondary  Glaucoma

There were 63(1.25%) patients with secondaryglaucoma.1out of which 53 subjects (84.12%) were phacomorphic glaucoma & 10 subjects had uveitic glaucoma (15.87%). Mean CCT value was 540+/- 5 microns. 

Discussion

At the turn of century, WHO and the International Agency for Prevention of blindness launched the Vision 2020: the right to sight initiative.1 The most recent estimates from WHO reveal that 47.8% of global blindness is due to cataract and in south Asia region which includes India, 51% of blindness is due to cataract.2 Since cataract is a major cause of avoidable blindness in the developing countries, the key to the success of the Global Vision 2020: the right to sight initiative is a special effort to tackle cataract blindness.3 This can be

achieved by screening camps in rural India. Cataract and glaucoma are frequently coexisting ocular conditions in the elderly population.Pre-existing glaucoma could remain undiagnosed if an inadequate preoperative evaluation is performed. According to the Chennai glaucoma study, 39% of the phakic subjects with glaucoma in urban population had significant cataract.7 If the healthcare system could detect these cases when they present for cataract surgery it would dramatically improve the detection rates for glaucoma in the population (current detection rates are 7.8% for primary glaucoma in the urban cohort4 and 1% for the rural sample).7 The prevalence of glaucoma in our study is 5.99% of those planned for cataract surgery. If these numbers are similar for the rest of the country this approach would result in detection of a large number of those with undiagnosed glaucoma. For many people in the country the only point of contact with the eye care system is when they seek or are “screened” for cataract surgery. Inadequate or inappropriate examination at this time is a lost opportunity to detect and treat other non cataract ocular pathology. Unless people go for periodic eye checkups that advocate a comprehensive eye examination at each visit, the rate of undiagnosed glaucoma in India will remain high.

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