Cataract surgery

Cataract surgery is probably the commonest surgery to be performed all around the globe, and also one of the safest. Once a cataract forms inside the eye, the only method to restore good vision is the surgical extraction of the cloudy lens. This is followed by the implantation of an artificial lens in its place that performs the function of the natural lens. Phaco-emulsification is the commonest method of cataract surgery. Explained below are the various techniques of surgery and the different types of lenses available for implantation.

Phaco-emulsification

This is a technique by which the cataract is liquefied and removed from inside the eye by a special equipment known as the Phaco-emulsification unit. The actual operation is carried out through a 2.8mm incision with the help of a titanium needle vibrating at the rate of about 40000 times per second. The needle emulsifies the cataract which is then aspirated.

Earlier, cataract surgery was performed through an incision as large as 10-12mm. Phaco has reduced this size drastically to 2.8mm. This eliminates the need for stitches as the wound is small and self-healing. Also, phaco reduces the risk factors associated with surgery, decreases the recovery time with early vision stabilization, and helps in reducing the surgically induced astigmatism.

Stellaris Micro-Incision Cataract Surgery

Also referred to as S-MICS, is a superior form of Phaco-emulsification in which the incision size is further reduced to a mere 1.6-1.8mm. The surgery is carried out by the Stellaris Phaco-emulsification system. It offers greater safety at the time of the surgery with reduced risk of intra-operative complications. The micro-incision means much less discomfort after surgery and quick post-operative recovery. Because the incision is so small, the astigmatism induced is almost nil.

          

Types of Intra-Ocular Lenses

Rigid Lenses

These are the conventional intra-ocular lenses. They are made up of a special material called PMMA (Polymethyl methacrylate). Rigid lenses have been in use for a long time but are now being gradually replaced by foldable lenses because of a few drawbacks. As the name indicates, they are rigid in nature, and so, a larger incision of 5.2mm is required for their insertion as compared to 2.8mm for foldable lenses. This increases the risk of post-operative endophthalmitis, delays wound healing and increases the surgically induced astigmatism. Also, glare experienced by patients, especially at night, is significantly greater. Such lenses are now seldom used in the developed world.

Foldable Lenses

These are a step above the conventional rigid lenses. They are made up of a special optical material that, as the name suggests, is foldable in nature. This allows the surgeon to “fold” the lens on itself and insert it inside the eye through a smaller incision with the help of a special instrument, the injector. The smaller incision offers the patient many advantages including less trauma, faster recovery, minimal post-operative astigmatism and less chances of infection.

Another major advantage of foldable IOLs is less glare, especially at night time. The larger size of these lenses allows a more uniform refraction of light. On the other hand, patients with rigid lenses might experience some glare, more so, with direct light. This is due to their smaller optical size which may cause irregular refraction of light from the edge of the lens.

Aspheric Lenses

Aspheric lenses are an advanced type of foldable lenses. They are aberration free. With advancing age, aberrations develop in the cornea of the eye which diminish the quality of vision in dim light. Such changes are neutralized by aspheric lenses and, hence, the latter improve the quality of vision at night time.

Multifocal Lenses

Multifocal lenses go a step further than the above mentioned intra-ocular lenses by overcoming a major drawback of theirs. They allow for near vision in addition to vision for distance, hence, allowing the patient to be considerably independent of glasses even for near work.

These lenses are based on a principle, somewhat similar to that of bifocal spectacles. Bifocals help a person for near as well as distance as they incorporate both glass powers in the same lens. The same is true for multifocal IOLs, the difference being that the latter are ‘multifocal’ instead of ‘bifocal.’ These lenses are made up of rings of gradually varying powers that allow for appropriate focusing of light rays from objects at varying distances.

Multifocal lenses, too, are foldable in nature and, hence, can be inserted through a small incision of only 2.2mm.

Some patients might experience a mild visual discomfort after multifocal lens implantation, such as the appearance of fine rings in the visual field. These usually disappear after the other eye is operated upon and a similar lens inserted. This balances the visual mechanism in both eyes. For this reason, patients opting for multifocal lenses are advised to get their other eye operated upon as soon as possible, usually within a month of the first. Also, it is to be mentioned that though multifocals help for near vision as well, glasses may be required for very fine work.

Micro-incision Lenses

Micro-incision lenses or MILs are the latest generation of unifocal lenses to be introduced. Their main quality is the ability to be inserted into the eye through an incision as small as 1.8mm. The patient is operated upon by a more advanced form of phaco-emulsification called S-MICS or Stellaris Micro-incision Cataract Surgery. The greatly diminished wound size results in superior post-operative comfort and a much faster recovery as compared to regular phaco-emulsification where other lenses are implanted. In addition, all the advantages of aspheric lenses are provided by MILs.

Yag Laser Capsulotomy

The natural lens has a cellophane like outer lining called the capsule. During cataract surgery, the back membrane of the lens, the posterior capsule, is left in place to support the artificial lens implant. The posterior capsule is normally clear and transparent. However, a majority of the people who undergo cataract surgery eventually develop a haziness or thickening of this membrane. Also referred to as “After Cataract,” this may develop months to years after the surgery. It is treated by a procedure called Yag Laser Capsulotomy, whereby the doctor uses a laser beam to make an opening in the posterior capsule to allow light to pass through and allow clear vision. This is a painless, out-patient procedure and never a part of the original cataract operation.

Refractive Surgery

Refractive Surgery is a laser guided correction of a person’s refractive error, minimizing or eliminating the need for glasses or contact lenses. Anyone who does not want to wear glasses or contacts, or feels visually, socially or functionally restricted by them may go for the surgical procedure. All types of refractive errors – myopia, hypermetropia and astigmatism can be corrected. The basic principle of the surgery is bringing about an alteration in the curvature of the cornea with the help of the Excimer laser that ablates it. This changes the optical power of the cornea.

Eligibility for Refractive Surgery

The following are some of the criteria that a person opting for refractive surgery must fulfill.

• Must be above 18yrs of age
• Must have a stable refraction for the last 6-12 months
• Must not have an ocular surface disorder like ‘dry eye’
• Should not have used contact lenses within the last 15 days
• Should have adequate corneal thickness

Before a patient is selected for surgery he/she is thoroughly examined by the doctor to exclude any contraindications. Besides routine examination, this procedure involves another test called the ‘Pentacam’ which is a detailed analysis of a person’s cornea- its shape, topography, thickness, elevations and abnormalities. It is only after this that the patient may be declared absolutely fit for refractive laser correction.

Wavefront guided Customized Laser Correction

The Excimer Laser is used for refractive laser surgery.  The wavefront laser is more advanced form of the Excimer. It scores over the latter in being a customized technique so that every surgical procedure is ‘tailor-made’ for that particular eye.

In this procedure, not only are the refractive errors corrected, but even the minutest of aberrations (called higher order aberrations) in the optical system of the eye removed, resulting in an improved quality of vision. The aberrations are detected by an instrument called aberrometer, and then both, the refractive error and the higher order aberrations fed into the laser machine. The laser then ablates the cornea in such a way that these aberrations are removed.

Various Techniques for Refractive Surgery

The same laser is used to ablate the cornea in all different types of refractive laser surgery. However, the technique adopted for the procedure may differ. Commonly, three different types of techniques are used.

Photorefractive Keratectomy (PRK)

In this technique, the corneal epithelium is removed and the surface of the cornea ablated with laser. PRK has been in practice since the 90s. Patients experience some degree of pain during the first 48hrs and recovery is relatively slower.

Laser Assisted in-situ Keratomileusis (LASIK)

In LASIK, a mechanical instrument called the ‘Microkeratome’ is used to raise a flap of corneal tissue. The laser is then used to ablate the cornea underneath the flap. The flap is then repositioned. The main advantage of LASIK is that there is no pain. However, occasionally, there might be flap related complications like button-holing, free flaps and corneal ectasias.

Laser Assisted Sub-Epithelial Keratectomy (E-LASIK or LASEK)

This is a somewhat hybrid procedure between PRK and LASIK. Instead of giving a cut in the cornea to raise a flap, the corneal epithelium is raised with the help of alcohol. The corneal surface is then ablated and the epithelial flap replaced. The main advantage of E-LASIK is that it is a tissue conserving procedure – a mere 50 micron thick epithelium is raised so that corneal tissue is not wasted in creating a flap. Also, flap related complications as with LASIK are avoided.

At Amritsar Eye Clinic, laser surgery is done on an out-patient basis. This means that the patient can go home immediately after the procedure. A relative or friend should accompany him/her. Usually, both eyes are treated at the same time.

Glaucoma Services

State of the art equipment for the diagnosis and treatment of glaucoma and its complications is available at Amritsar Eye Clinic. Annually, more than 3000 glaucoma patients receive some form of treatment here.

Facilities for the thorough management of the disease include the following:-

Tonometry

For the measurement of the Intra-Ocular Pressure (IOP).

Gonioscopy

For the visualization of the angle of the eye. Assessment of the angle is critical in Glaucoma as it helps to study any pathology which might be a hindrance to the outflow of aqueous.

Pachymetry

Assessment of the corneal thickness.

Pentacam

An advanced test for the assessment of the angle, the anterior chamber, besides the cornea.

Perimetry

It is the analysis of the visual field of the individual. The extent to which it is damaged by the glaucomatous process can be discerned.

Retinal Nerve Fibre Layer (RNFL) Analysis Test

Helps to study the retinal nerve fibre layer. This test can pick up glaucomatous damage upto 6yrs earlier than standard tests for visual field analysis.

Optic Disc Analysis

Detailed analysis of the optic disc by the OCT machine.

Yag Laser

Primarily used for iridotomy in patients of Acute Angle-closure glaucoma.

Argon Laser

For trabeculoplasty that may be required in some patients of glaucoma.

Filtration Surgery (Trabeculectomy)

May be resorted to in patients when the IOP cannot be adequately controlled with medications, or due to other reasons. An alternate outflow tract for drainage of aqueous is created.

UVEA Services

Amritsar Eye Clinic is well equipped to deal with various forms of Uveitis. Apart from basic facilities for the diagnosis of Uveitis like high magnification slit-lamps and indirect ophthalmoscopy, the centre offers the following to its uvea patients.

Fundus Photography

For visualization of the posterior part of the eye, often termed the Fundus.

Fundus Fluorescein Angiography (FFA)

Helps to study the Fundus in greater detail, with particular attention to the vasculature. Fundus photographs are taken after intravenous injection of a special dye.

Optical Coherence Tomography (OCT)

For the detailed study, at the microscopic level, of the macula, optic disc and the retinal nerve fibre layer (RNFL). It is of particular importance in the detection of Macular Oedema.

Ultrasound B scan

Gives a 2-D or cross-sectional image of the entire eye-ball. It helps in detecting complications like intra-ocular tumours, Retinal Detachment, swellings of the choroid and retina, etc.

Complications of Uveitis like secondary cataract and secondary glaucoma can also be well managed.

Neuro - Ophthalmology

Neuro-Ophthalmology is the branch of Ophthalmology that deals with eye problems associated with the nervous system, and with optic nerve disorders.

Clinical examination and investigative procedures related to Neuro-Ophthalmology

Perimetry

The assessment of a patient’s visual field. It may be damaged in some neurologic disease processes.

Optical Coherence Tomography (OCT)

Used to study the health of the Retinal Nerve Fibre Layer, and the extent of optic nerve damage that has occurred.

Contrast sensitivity testing

To determine the ability of a person to distinguish between various grades of contrast. This function may be affected in case of optic nerve disease.

Retina Services

Fundus Photography

For visualization of the posterior part of the eye, often termed the Fundus.

Fundus Fluorescein Angiography (FFA)

For a more detailed examination of the fundus with particular attention to the blood vessels. FFA requires an intravenous injection of a dye. This is followed by photography of the fundus. FFA is particularly useful in vascular diseases of the retina like Diabetic Retinopathy and vein occlusions.

Optical Coherence Tomography (OCT)

This technique allows examination of the retina in much greater detail, so to say at a microscopic level. Used to study the macula, the optic disc and the Retinal Nerve Fibre Layer (RNFL), it is invaluable in conditions like macular oedema, retinal dystrophies and degenerations, etc.

Ultrasound B scan

Gives a 2-D or cross-sectional image of the entire eye-ball. It helps in detecting complications like intra-ocular tumours, Retinal Detachment, swellings of the choroid and retina, etc.

Anti-VEGF therapy

Anti-VEGF (vascular endothelial growth factor) injections may be required in some patients of macular oedema and in case of profound neovascularization.

Cryotherapy

For the surgical management of conditions like peripheral retinal breaks and tears. It may even be required in painful blind eyes.

Laser photocoagulation

The Argon laser is used for photocoagulation of the retina in conditions like Diabetic Retinopathy, central retinal vein occlusion, etc.

Oculoplasty

Oculoplasty is that branch of Ophthalmology that deals with the structures forming the Adnexa i.e., the orbits, the eyelids and the lacrimal system.

Some of the Oculoplasty services available at AEC include the following:-

Entropion and Ectropion surgeries

Surgical management of malpositioned eyelids, whether inturned (Entropion) or turned outwards (Ectropion).

Ptosis surgery

For droopy eyelids.

Trichiasis treatment

For misdirected eyelashes.

Pterygium excision

Laser DCR surgery – or Dacryocystorhinostomy

For persistent watering of the eyes in sac problems.

DCT surgery

Also called Dacryocystectomy for persistent watering of the eyes in sac problems.

Other minor procedures like chalazion excisions,probings,etc., are routinely performed

Squint Services

Amritsar Eye Clinic provides the under-mentioned facilities to patients suffering from Squint.

General ocular examination in patients of squint

Synoptophore

For ophthalmic exercises in patients of squint, and for pleoptics to correct Amblyopia.

Surgical treatment of Squint

Cornea Services

Besides Refractive Surgery, Amritsar Eye Clinic offers the following services to patients of corneal disease.

Specular Microscopy

It is used for the study of the corneal endothelium- the health of the endothelial cells, their morphology, their density and other numerous parameters.

Pentacam

For the analysis of corneal topography. Both surfaces of the cornea, anterior and posterior can be analyzed. This is particularly important before Refractive Surgery, and also in the detection of various other corneal disorders like ectasias.

Corneal Collagen Cross-linking

Also referred to as C3R, is a new modality of treatment for Keratoconus. It may stop the progression of the corneal bulge, sometimes even inducing regression.

Aberrometry

Used for the detection and measurement of higher order aberrations before Refractive Surgery. The correction of these aberrations leads to a better quality of vision after surgery.

Photo-therapeutic Keratectomy (PTK)

The laser guided ablation of the cornea for the treatment of corneal opacities and some dystrophies.

Management of various medical disorders of the cornea