Dr Harsh Kumar
Glaucoma or ‘Kala Motia’ as known in common parlance is a blinding disease of the eye.It affects the optic nerve i.e. the nerve of sight, which carries the visual signals to brain. Worldwide data shows that by 2020, the number of persons with glaucoma will almost double from the recent estimate of 67 million. The general perception amongst the public at large is that it is a disease of old age and occurs only when the intraocular pressure (inherent pressure of the eyeball due to a fluid known as aqueous humor) is greater than 21mmHg. However, glaucoma is a multifactorial disease which can affect anyone from a newly born child to young healthy adults to elderly people.
Even people having an intraocular pressure in the normal range can have glaucoma, which isthe ‘normal tension’ variant. Those with myopia, history of blunt eye trauma, systemic problems like high/low blood pressure, diabetes mellitus, thyroid disorder, migraine, peripheral vascular disease, on steroid medications and with a positive family history are at a greater risk.
Possible symptoms of Glaucoma
Glaucoma is a slowly progressivegenerally painless disease and patients rarely experience drastic vision loss until very late when the central vision gets affected. So even if a person has a 6/6 visual acuity, he/she can still have glaucoma and be unaware about it.Therefore, knowledge of subtle indications can be helpful in the long run and if a person is experiencing any of the symptoms mentioned below, a visit to the ophthalmologist should not be deferred –
* Inability to adjust the eyes to dark rooms
* Poor night time vision
* Frequent changes in reading glass prescription
* Gradual loss of peripheral vision i.e. inability to see on the sides
* Blurred vision
* Feeling of a blind area in the eye
* Seeing rainbow colored halos around lights, especially in evening time
* Severe eye pain along with facial pain, nausea, vomiting and red eye
Types/causes of Glaucoma
As mentionedabove, the inherent pressure of the eyeball is due to a fluid known as the ‘aqueous humor’ which is produced within the eye and drains out from an area in the eye known as ‘the angle’. Depending upon the narrowness of this ‘angle’, Glaucoma is divided into two main types -open angle and angle closure. While the primary treatment for open angle type is medications, laser therapy is needed to halt the angle closure mechanism which if otherwise overlooked may warrant surgery after some years; it is the angle closure type which is more common in Asians.
Glaucoma in children is a highly visually debilitating disease and requires surgery at the earliest. Children less than 3 years should be watched for abnormal enlargement and bluish appearance of one or both eyeballs, along with inability to see clearly. Use of over-the-counter steroid drops for eye allergy is a very common cause of high intraocular pressures in young children which after prolonged usage can cause irreversible blindness. A lesser known form is the ‘juvenile glaucoma’ which occurs in young adults in second-third decade. Special form of glaucoma can also occur in uncontrolled diabetics or those with cardiovascular problems.
Even though glaucoma causes irretrievable vision loss, all hope is not lost.In today’s world, with the availability of modern technology and latest software, the disease can be picked up much earlier than was possible a few years back. Computer based programmes like Scanning Laser Polarimetry (GDx), Heidelberg Retinal Tomogram (HRT) and Optical Coherence Tomography (OCT) of Optic Nerve Head (ONH)/ Retinal Nerve Fibre Layer (RNFL) and Ganglion Cell Complex (GCC macula) are some of the latest early diagnostic tests in this field. Also faster techniques (Matrix/FDT) for assessing the functional loss are now available which take half the time taken by conventional visual field testing for glaucoma detection.
Advancements have occurred not only in the diagnostic techniques but also in the treatment modalities. Variations in the intraocular pressure can now be monitored over 24-hours by use of a contact lens based device called the ‘Triggerfish’. Armamentarium of medications available to the physician is also ever evolving and drops can now be tailored to individual needs. Availability of preservative free eyedrops which cause lesser irritation and stinging, fixed drug combinations and longer acting drugs which make for easier dosing have improved the quality of life index in glaucoma patients. Even those who present with very advanced form of disease unresponsive to treatment have the option of valve implant surgery. The success rate of conventional glaucoma filtering surgery has also improved of late by use of biological agents like Amniotic membrane and Ologen implant.
Day to day prevention tips –
* Comprehensive eye check-up every 2-4 years after 40 years age and every 1-3 years for those with above mentioned risk factors. (As recommended by American Academy of Ophthalmology Preferred Practice Pattern 2005)
* Regular exercise and life style modification
* Adequate intake of anti-oxidants
* Avoid smoking/ drinking excessive caffeine
* Avoid drinking excessive water at one time
* Avoid yoga exercises which excessively increase the intra-abdominal and intra-thoracic pressure and those which increase the blood flow to head likesheershasan
Hence glaucoma although a dreaded disease, can be halted with timely intervention, correct diagnosis, regular eye check-up and life style modifications.
(The author is Senior Consultant Glaucoma & Catartct)
Dr Harsh Kumar