A cataract is a clouding or opacity of the naturally, clear, crystalline lens of the eye which most commonly occurs as a consequence of the aging process and also exposure to ultra-violet light. Cataracts can also occur in younger patients. Cataracts can also be a consequence of other diseases, particularly diabetes and some medications, especially steroids. By the age of 70 most patients have some degree of cataract formation which may or may not be symptomatic and require treatment. Cataracts are the leading cause of visual impairment and blindness worldwide.
Cataracts are removed by a highly sophisticated micro-surgical operation called phacoemulsification in which the natural lens of the eye is removed and replaced with an intraocular lens (IOL). These come in the form of standard or mono-focal lenses for patients without astigmatism and toric IOL’s for patients with astigmatism (which are the majority of the patients on each operating list). Also available are tri-focal intraocular lenses which are available for selective patients which means that patients do not need glasses for any tasks following successful surgery.
The results of cataract surgery are unbelievably excellent and the procedure is recognised as both the most common and most successful operation performed worldwide.
REFRACTIVE LENS EXCHANGE
Refractive lens exchange is an operation in which the crystalline lens of the eye is removed and replaced with an intraocular lens to correct a refractive error such as hypermetropia, myopia, astigmatism or a combination thereof. The procedure is performed as a micro-surgical one in an operating theatre and involves removal of the natural crystalline lens by a procedure known as phacoemulsification and its replacement with an artificial intraocular lens (IOL). The IOL can be either a mono-focal lens to correct patients without astigmatism or a toric intraocular lens to correct patients with astigmatism. Tri-focal lenses are used for selected patients who wish to be independent of glasses altogether.
Glaucoma is often called the “sneak thief of sight” because it can occur without the patient becoming symptomatic. Glaucoma most commonly occurs in the older age group but can occur in younger patients as well. It is diagnosed and managed with a variety of tests such as intraocular pressure measurement, observation of the optic disc, pachymetry (measurement of the central corneal thickness), assessment of the Retinal Nerve Fibre Layer thickness and ganglion cell layer with the OCT (Optical Coherence Tomography) and computerised visual field analysis.
The usual treatment for glaucoma is eye drops of which there are many on the market. For certain patients there is a laser treatment known as Selective Laser Trabeculoplasty which can be offered at Dr. Forster’s Wesley rooms and is highly effective in lowering the intraocular pressure (which is the aim of glaucoma management). A recent innovation in the management of glaucoma is the introduction of the revolutionary iStent which is generally performed in association with cataract surgery although can be done as a stand alone procedure and, in many cases, results in the patients being less dependent on their eye drops or, in some cases, able to manage without any drops at all.
Although the majority of patients can be treated using the above methods, some patients are predisposed to angle closure glaucoma, particularly patients of Asian descent. This type of glaucoma can be prevented by a simple laser procedure known as Laser Peripheral Iridotomy which is also available at Dr. Forster’s Wesley rooms.
A pterygium is a wedge-shaped growth of thickened tissue extending from the white of the eye (sclera) on to the cornea and is usually due to exposure to ultraviolet light. A pterygium needs to be removed if it has grown across the cornea to a degree where it has caused astigmatism (irregularity of the cornea), if vision has been impaired or for cosmetic reasons.
In order to treat a pterygium it is removed via micro-surgery in a day surgery under local anaesthesia and an auto-conjunctival transplant is sutured in its place. The auto- conjunctival transplant involves transplanting some conjunctival tissue (the surface layer over the white of the eye) from underneath the upper eyelid to cover the area that the pterygium has been removed from. The transplant is performed in order to result in good cosmesis (how the eye looks after surgery) and to ensure virtually no recurrence of the pterygium.
Patients can expect a return to full vision after the surgery. Full recovery to health takes four to eight weeks during which time patients will require daily drops.
Macular degeneration usually occurs in the older age group when the macula becomes damaged due to its deterioration or break down. When the normal function of the macula is disrupted the centre of the field of vision is affected. Macular degeneration can affect both near and distance vision. There are basically two sorts of macular degeneration, the more common is what is known as dry macular degeneration for which there is no treatment apart from preventative dietary treatment. For the wet form of macular degeneration, which can be detected clinically or with the OCT (Ocular Coherence Tomography), intra-vitreal injections have now been introduced and are spectacularly successful in treating this form of macular degeneration.
It is possible to reduce the risk of developing macular degeneration by eating a diet rich in green leafy vegetables such as kale, spinach, brussel sprouts, broccoli as well as brightly coloured fruit and vegetables (corn, capsicum, carrots), and eat fish and
other omega rich foods two or three times a week, particularly oily fish such as salmon, tuna and sardines, and eat a handful of nuts twice a week.
Patients who suffer from diabetes mellitus may develop diabetic retinopathy which is the most common cause of visual impairment in diabetes. It occurs when the network of blood vessels nourishing the retina becomes damaged, a process than can result in varying degrees of visual impairment and sometimes blindness, but diabetic retinopathy can be present without any disturbance of vision at all.
Diabetic retinopathy can either be background or non-proliferative retinopathy or proliferative retinopathy which is a more serious condition. Diabetic retinopathy can result in damaged blood vessels leaking into the surrounding retina resulting in retinal oedema (serous fluid), retinal haemorrhages (blood), and retinal exudates (fat) or in the more serious proliferative retinopathy retinal vessels may wither away or become blocked and abnormal new vessels may grow to replace them which may bleed in the retina and vitreous (jelly of the eye) causing loss of vision. It is important that all patients with diabetes are checked regularly, preferably annually. This is done with a clinical examination of the vision and the back of the eye, and now there is the OCT (Ocular Coherence Tomography) which is invaluable in detecting evidence of diabetic macular oedema. Some patients may need further investigation such as Fluorescein Angiography.
When diabetic retinopathy is detected and there is a prospect of interfering with the vision it can be treated by laser, intra-vitreal injections or intra-vitreal implants, all of which have proved successful in preventing loss of vision.