Frequently Asked Questions (FAQ)
Our eye functions like a camera with two lens in front (the cornea and the the crystalline lens).The light rays have to pass through these two structures and reach the retina, which when healthy transmits information to the brain,which in turn processes this information ,leading to the phenomenon of vision.When the crystalline lens or natural lens in the eye losses its transparency due to some cause,it can no longer transmit light rays in a clear manner thus causing distortion or diminution of vision.Depending on grade and type of cataract the vision can blur to varying extents.Other symptoms include doubling of vision,frequent change in spectacle power(increase or decrease),glare,difficulty in night vision etc.The changes in spectacle power are produced due to changes in the refractive property of the lens due to the cataract.In some instances the vision can also become clearer temporarily due to these changes,however if left to progress the cataract causes reduction of vision.If left untreated it can cause blindness in advanced stages.
Cataract surgery is usually advised when the cataract starts affecting the vision.Some forms of cataract cause early distortion of vision whereas some cause late decrease in vision.Apart from symptoms,Your doctor will assess the cataract and remaining structures of the eye, and advise surgery based on level and type of cataract,health of the eye etc. With advances in treatment of cataract using modern phaco-emulsification and advances in the technology involved in the machines used,it is preferred to extract the cataract before it becomes mature or advanced.This is because extracting a softer cataract puts less strain on the eye than an advanced cataract.
The usual cataract surgery takes somewhere between ten to 20 minutes.The eye is anesthetized before the surgery and hence it is a painless surgery.Surgery is performed through a small sutureless(no stitches) incision.Cataract is emulsified and extracted through the same incision followed by implantation of a foldable intraocular lens(IOL).
he cataractous lens is emulsified or liquified using ultrasound energy from the tip of the phaco machine probe.This material is sucked back into the device thus clearing the cataract.This technique avoids large incisions of older forms of cataract surgery
An intra ocular lens(IOL) is a bio compatible or inert lens which is placed inside the eye(usually in the lens capsular bag) after clearing the cataractous lens material from within the natural lens bag.During phacoemulsification a foldable IOL is usually placed .The advantage of this type of lens is it can be inserted with the help of an injector into the eye through the small phaco wound.Depending on the material and make IOLs can be of various types.
It depends on the IOL type implanted, the shape and health of your eyes and some other factors.Modern day IOL designs and micro incision surgeries in experienced hands have made precise vision a possibility, thus reducing dependance on spectacles.
Traditional monofocal IOLs have single focus usually for distance thus necessitating glasses for reading and sometimes for distance as well.
Multifocal IOLs and EDOF lenses give better range of vision reducing the need for spectacles. In some eyes toric IOL are advised . Toric IOL s correct the preexisting astigmatism of the eye and hence reduce need for glasses again. Both monofocal and multifocal lenses come in toric designs customisable to your eyes and needs. As cataract surgery is a one time event it is better to know your options and go for what's best for you on a long run!
FAQ ON REFRACTIVE SURGERY/ LASER VISION CORRECTION/LASIK/SMILE
Laser vision correction (refractive surgery) refers to a group of procedures used to correct refractive errors like myopia, astigmatism, hyperopia in order to reduce dependancy on,or get rid of spectacles or contact lens.
Broadly the following methods are available currently for this purpose
ReLEx SMILE
SURFACE ABLATION
LASIK
LASIK is again categorised as FEMTOLASIK(Bladeless LASIK) and Blade lasik.
Currently the best treatments for myopia and astigmatism correction are ReLEx SMILE and in some instances advanced surface ablation in terms of their safety profile as both these techniques avoid a flap.So issues of dry eyes and corneal weakening are minimum with above techniques.
Flap procedures like LASIK can also give a crisp vision and can be safe provided your cornea is healthy and refractive error is within certain limits.
Topography guided LASIK, Contoura are again forms of Lasik beneficial in certain individuals with irregular cornea or astigmatism.
To decide whether your eye is fit for refractive surgery(Laser Vision Correction) your doctor will perform a thorough eye checkup including refraction, examination of your eye under the slit-lamp, retina evaluation etc.Eye drops will be applied to examine your retina and to confirm the spectacle power of your eyes. A corneal topography scan will be performed on your eyes which helps decide the suitability for this procedure. The entire checkup can take upto an hour or sometimes more based upon the need. If you are a contact lens user your doctor will advise you to discontinue contact lens few days (minimum of 3 days,better if 1 week) before the testing process.
Laser treatments are painless and quick procedures which take around 10 to 15 minutes.They are usually performed with numbing eye drops which makes the entire procedure painless.The LASER application itself is completed within seconds as current laser systems are very fast and accurate. You will be asked to keep both your eyes open and look at a light which will help you look in a straight direction which ensures proper treatment.
Immediately after the procedure it is normal to experience slightly foggy vision and mild eye irritation may be there. It is better if you take couple of days to 1 week rest after the procedure again depending on the type of procedure, the details of which your doctor will provide you.
You need to be atleast 18 yrs old(above 20 yrs is still better) with a stable refraction(spectacle power) in the last one or two years. Your eyes should be healthy. And corneal topography test should reveal a normal cornea with adequate thickness. SMILE is a treatment for myopia (short sightedness). It can also correct myopic astigmatism.
During the healing period after Laser procedures on the cornea, some people may experience glare or haloes or transient distorted vision.This is more with older laser systems. Most often these symptoms are transient and rare with present laser systems. If you have a large pupil size you may be more prone to such problems especially at night time. During the postoperative period of 2 to 3 months after any form of surgery on your eyes, your eyes and entire visual system goes through an adaptation phase. This is called ‘neural adaptation’. Haloes and glare are most often experienced in this phase when your eyes are getting used to their new state of vision.
Also dryness of eyes is one of the most common causes of such symptoms after eye surgery, especially if you sit in front of computers for long hours or use mobile phone and gadgets for long duration . This is easily correctable with use of lubricants.
COMPUTER VISION SYNDROME(CVS)
This condition encompasses a group of symptoms or problems associated with prolonged use of computers.It can present itself even after usage of smart phones,tablets or any modern devices requiring prolonged staring or reading and sitting in odd postures for a long duration.It usually affects computer professionals or people spending more than 3 hours in front of the computer. The symptoms can range from discomfort in the eyes, dry eye symptoms like irritation, pricking,burning of eyes, excess watering, heaviness or tiredness around the eyes to headache.Sometimes there can be blurred vision .The symptoms may be mild or severe affecting the performance of the individual significantly. Also postural problems like chronic neck pain,back or hand pain may be associated.
The eye symptoms of CVS are usually due to subconscious decrease in blink rate due to staring at computer screen, thus leading to the drying up of the eye's surface.This in turn leads to dry eyes and resultant problems.The drying effect of air-conditioning in the office also plays a role.There can be refractive errors contributing to the problem which when uncorrected can cause blurry vision and headaches.Glare from the computer screen or from improper lighting can also lead to CVS.
To prevent this problem it is important to maintain good lighting in the work place with no reflections from the computer screen, optimal brightness of the computer screen. Frequent blinking and reminders to take a break every 20 minutes or so, helps reduce the symptoms along with lubricants prescribed for the dry eye symptoms. An eye checkup may reveal an underlying dry eye problem or refractive error. Correction of any refractive error if present as necessary helps relieve symptoms. Correct posture and support to the arm and back are very important,with the computer screen being slightly below the eye level.