Glaucoma is a group of eye diseases that can cause vision loss and blindness by damaging the optic nerve. It occurs when aqueous fluid builds up in the front part of your eye. The extra fluid increases the pressure in your eye, damaging the optic nerve.
Risk factors for Glaucoma
- Family history of Glaucoma
- Age above 40 years
- Diabetes
- Hypertension
- Myopes
- Prolonged use of steroid medications
Gonioscopy
Gonioscopy is a procedure by which the doctor uses a specific type of lens to grade the angle of the anterior chamber to assess its depth, through which we can determine the risk of angle-closure in the eye. By this examination, we can grade the Glaucoma as Open-angle or closed-angle.
Types of Glaucoma
1. Congenital Glaucoma
2. Open-angle Glaucoma
3. Closed-angle Glaucoma
Symptoms and signs
- Increased watering of eyes
- Sensitivity to light
- Constant eye rubbing
- Corneal oedema
- Corneal enlargement
- Bluish discolouration of the eye due to thinning of the sclera
- Large eyeball
- Increased IOP
Diagnosis
A complete ophthalmic evaluation is carried out under general anaesthesia, which includes the following:
- Estimation of IOP using tonometry which is a device used to assess the pressure inside the eye.
- Measurement of Corneal diameter.
- Ophthalmoscopy to assess the Optic disc.
- Gonioscopic examination.
Treatment
Medications don’t seem to be very helpful in congenital Glaucoma; hence surgical management is the only choice available to preserve the vision.
Open-angle Glaucoma
Primary open-angle Glaucoma is a simple chronic Glaucoma of adult-onset and has the following features:
- Raised intraocular pressure > 21mmHg
- Anterior chamber angle appears open
- Optic disc cupping
- Visual field defects
Symptoms
The patient is typically asymptomatic until significant loss of vision happens.
In advanced stages, the patient might complain of:
- Delayed dark adaption to light.
- Visual field defects.
- Occasionally headache and eye ache.
Investigations
- Tonometry – to assess the IOP
- Diurnal variation test
- Gonioscopy
- Slit-lamp examination
- Ophthalmoscopic examination
- Perimetry to assess the field defects
- OCT –Retinal nerve fibre layer
Management
The aim of the treatment is to reduce the intraocular pressure to a level the optic disc damage does not occur.
The treatment options available are,
- Medical therapy - Topical antiGlaucoma medications
- Laser procedures
- Filtration surgeries
Angle-closure Glaucoma
Angle-closure Glaucoma occurs when there is an obstruction in the flow of aqueous humour due to variation in the anatomical structures of the eyeball.
Risk factors
- Hypermetropic eyes
- Eyes with a narrow-angle of the anterior chamber
- Hereditary
Acute attacks of angle-closure Glaucoma are characterised by,
- Ocular pain - acute in nature
- Nausea, vomiting
- Rapid loss of vision
- Coloured halos
- Lid oedema, semi dilated pupils not reacting to light
- Closure of the angle of the anterior chamber
- Markedly elevated IOP
Treatment
- Immediate medical therapy to lower the IOP
- Laser procedures to open the closed angles
- Filtration surgeries
Conclusion
Glaucoma could be a silent killer of vision. Every individual above 40 years of age must get their intraocular pressure and retinal examination done annually.
