The Prevalence of Open Angle Glaucoma within Blood relatives, with a focus on the role of familial predisposition as a causative factor

Abstract

Purpose:

The purpose of the study is to identify the frequency of open angle glaucoma among blood relatives enquiring the influence of familial predisposition as a causative factor.

Methods:

All patients aged 30 years and above, with or without prior diagnosis for POAG were subjected to the history and examination at the department of ophthalmology OPD at MGM Medical College And Hospital. Those individuals who were already diagnosed and presented signs and symptoms of POAG were re-examined at the ophthalmology OPD of MGM Medical College and Hospital.  Torchlight was used to begin ophthalmic examination to exclude ptosis, pupillary abnormalities and an approximate estimation of the depth of the AC. Tests were performed to eliminate indications of secondary glaucoma, and Pathologies of iris have also been excluded. Refractive errors were identified and NCT was documented in all cases. For the evaluation of the angles or pigment deposition status in TM, gonioscopy was done. After dilatation, the patient was dilated  and examined with a 90D and indirect ophthalmoscope to exclude retinal diseases that might lead to secondary glaucoma or confound Perimetry results. Disc size, cup size, Neuro retinal rim thinning, notching of the NR rim and disc haemorrhages were carefully examined within the optic discs for the  signs of glaucomatous optic neuropathy.  Both eyes were observed and compared for the size of the cupping. Standard Automated Perimetry (Humphrey Visual Field Analyzer) and Goldmann Applanation Tonometry were subjected all the patients suggestive of POAG and raised IOP on NCT.On  Gonioscopy Open Angles was crucial for POAG diagnosis. All those  the patients who confirmed the diagnosis of POAG were selected. All available immediate relatives viz. siblings, parents and children of age 30 years and above (1st inclusion criteria) were asked to attend the OPD of Ophthalmology at MGM Medical College. They were subjected to detailed history taking and underwent detailed Ophthalmological examination as per the above-mentioned procedures.
Results

The study comprised a total of 1380 subjects(mean age 55.56 ± 12.70 years; range 30 to 79 years and above), those who were enrolled for this study It shows in our study that non affected relatives are 818(59.3%),while affected with POAG is 562 (40.7%). It shows in our study that non affected relatives are 818(59.3%),while POAG is higher in parents having frequency of 301(21.8%) , as compared to siblings whose frequency is 181(13.10%) and much less within children 80(5.80%).

Conclusions

In the present study, patients who are suffering with POAG exhibit greater degree of risk of transmitting this disease to their blood relatives. By identifying, the distinct blood relatives, POAG would be the key criteria for understanding the pattern of disease expression, taking better precautionary measures amongst family members. Our study clearly suggests that glaucoma possess a strong family linkage that attributes for propagating the disease through generations. From carrying out a prospective evaluation on a hospital based study aided towards broadening the scope of pre-existing studies by including members of the family that are  direct relatives. This study also reconfirms that the blood relatives of known POAG patients especially parents are the most at risk group to develop primary open angle glaucoma in Eastern Indian population.