Are you at risk for glaucoma?
All of us are at risk for glaucoma, which is why ophthalmologist recommend regular eye checks for everyone, since glaucoma usually has no symptoms.
In fact, the American Academy of Ophthalmology, recommends a comprehensive eye examination every two years especially after the age of forty, and an annual eye examination every year after the age of sixty, in patients who do not any special risk factors for glaucoma. The recommendations for people of Hispanic, African or Asian ancestry may be an annual eye check after the age of forty. In addition to this, the patient’s individual risk factors for glaucoma as assessed at baseline, will determine the frequency of follow-up visits.
The major known risk factors for glaucoma are discussed here, and your risk for disease will be determined by your eye doctor keeping all of these factors in mind.
Age
Even though glaucoma is described as a disease of the elderly, but it can affect almost any age group, including new born children (congenital glaucoma). Typically, the risk of angle closure glaucoma is known to increase in the 40s, while that of open angle glaucoma peaks in the 60s. In fact, since glaucoma is often considered an accelerated loss of nerve cells, which increases with age, it is often called Alzheimer’s of the eye.
Family history
People with family history of glaucoma, especially first degree relatives of glaucoma patients, are at a higher risk. So, if your parents or siblings are suffering from glaucoma, you must get yourself checked. A first-degree relative with POAG means your risk can be as high as 3 to 13 times that of normal population. The risk is thought to be higher if the affected relative is a sibling.
Racial predilection
POAG is more prevalent in people of African-Caribbean descent as compared with Caucasians. Hispanic and African ancestry means a higher risk for a severe, and more aggressive form of disease. Asians and Inuits are more prone to angle closure glaucoma, while the incidence of POAG is more in Caucasians.
Eye pressure elevations
Patients with high eye pressures are at increased risk of glaucoma, in fact, eye pressure or intraocular pressure, IOP, is the only modifiable risk factor for glaucoma.
Optic Nerve Structure
Patients with a certain morphology or structure of optic disc or optic nerve are at a higher risk of glaucoma, this includes a high cup disc ratio, disc asymmetry, thin retinal nerve fiber layer or RNFL defects etc.
Gender
Women are prone to angle closure disease and Normal Tension Glaucoma (NTG).
Secondary to eye diseases and trauma
Those patients who have a history of eye trauma or multiple eye surgeries are also at a higher risk of secondary glaucomas. For example, Post Traumatic Glaucoma, Post Vitreoretinal Surgery Glaucoma, Uveitic glaucoma.
Drug use
Steroid use, especially the use of topical steroid eye drops, increases the risk of glaucoma (Steroid induced glaucoma). Other drugs which have been implicated in causing or aggravating glaucoma include cholinergic or anticholinesterase agents, anti-depressants, anti-convulsants, drugs for Parkinsonism and migraine. Drugs like Ecstacy and certain cocaine like drugs can also precipitate angle closure glaucoma.
Systemic diseases, especially diabetes: People with diabetes are at a much higher risk of glaucoma. The risk associated with other endocrine diseases is not as well defined. Patients with high blood pressure are also considered to be at a higher risk than normal, but the role of high BP in development of glaucoma is not well defined. Patients with low blood pressure, especially at night, may be at a higher risk of Normal Pressure Glaucoma (or NTG).
Vasospastic diseases: Patients with vasospastic diseases like migraine and Raynaud’s phenomenon also have an increased risk of glaucoma.
Low central corneal thickness: Patients with corneal thickness less than 520 microns are at a higher risk of glaucoma incidence and progression than those with thicker corneas. This could be because of errors in measuring eye pressure (IOP tends to be read lower in patients with thinner corneas), and also because thinner cornea may imply less rigid support structures around the optic nerve, making it more prone to damage.
Refractive error: Need for glasses of high power, either negative (myopia) or positive (hypermetropia), can increase your risk of POAG and PACG respectively.
Structure of the eye: Patients with narrow angles (3.8% prevalence in white and 8.5% in Asian), short axial length, thicker and relatively anteriorly positioned lenses, flatter corneas, and shallow anterior chamber are more predisposed to angle closure glaucoma. Exfoliation, pseudoexfoliation and excessive angle pigmentation can increase the risk of specific kinds of glaucoma, namely Exfoliative, Pseudoexfoliative and Pigmentary Glaucomas respectively. Recurrent disc hemorrhages are associated with an increased risk of NTG.
Genetic Predisposition: Several genes associated with glaucoma have been identified, but these are not seen in a majority of glaucoma patients. It is therefore believed that the hereditary aspect of glaucoma is controlled by several genes (polygenic) and that gene-environment interactions are more important in the disease process.
Major clinical trials have defined the following risk factors:
A. Ocular Hypertension Treatment Study, OHTS: Risk factors for development of POAG
1. Older age
2. Higher IOP
3. Thinner central corneal thickness
4. Larger vertical cup-disc ratio
B. Collaborative Normal Tension Glaucoma Study, CNTGS: Risk factors for progression
1. Gender: Female
2. Recurrent disc hemorrhages
3. History of migraines
C. Early Manifest Glaucoma Treatment Trial, EMGT: Risk factors for progression
1. Higher IOP
2. Exfoliation
3. Older age
4. Bilateral disease
5. Recurrent disc hemorrhages
