What is cataract surgery?
Cataract surgery is the most common ophthalmic surgical procedure performed globally. According to WHO, 39 million people are blind i.e. corrected visual acuity of 3/60 [recognizing at 3 meters what a person with normal acuity can recognize at 60 meters] and less in the better eye, with cataract being responsible for 44.8% of these impairments. A significantly larger proportion of people suffer from low vision (visual acuity in the range of 6/18 to 3/60), which adversely affects their levels of independence, safety, and productivity An opalescent or discolored lens might distort the light passing through it, and blocks adequate light to cause blurry vision, to the point where glasses would not be helpful. Thus cataract is opacity in the crystalline lens of the eye, leading to diminished visual function and acuity.It is a chronic condition that does not resolve spontaneously.Till date, preventive and medical interventions for treating cataract have been proved to completely cure the condition, hence surgical removal of the cloudy natural lens and replacing it with an artificial, transparent intraocular lens (IOL), remain the only effective option for visually disabling cataract.
Causes of Cataract
- Congenital: Rarely cataract may be present at birth. Impropermaternal nutrition increases the risk of acquiring infections such as rubella, also known as German measles,which increase the likelihood of congenital defects in the fetus. Intrauterine placental hemorrhage is another condition that deprives the fetus of oxygen predisposing it to developmental defects. Congenital form of cataract can have a unilateral or bilateral presentation.
- Aging: Impact of an aging body predisposing to the development of cataract is indisputable. Aging is associated with multiple metabolic and hormonal changes in the body which may adversely affect strength and flexibility. At approximately,in the fifth decade of life, the lenses begin to lose their flexibility and consequently their ability to refract and focus light on an object. Thereafter patients develop a tendency to view objects up close so as to focus light properly. This condition is medically referred to as presbyopia, or as the layman call it the aging eyes. Gradually as the lenses continue to lose their flexibility, they eventually harden and become opaque.
- Sun exposure: Proteins are ubiquitously present in the body and they are extremely sensitive to ultraviolet light. Prolonged sun damage causes oxidative stress in the lenses and release of free radicals which consequently damage and discolor the lens.
- Metabolic or Secondary: Include non-age related diseases and conditions of the body with an increased risk of developing cataract.Chronic anterior uveitis or inflammation of the uvea i.e. the middle layer of the eye is the most common disease with susceptibility to secondary cataract development. Acute congestive angle closureglaucoma is a severe condition which rapidly increases the intraocular pressure forming small grey- white subcapsular or capsular opacities.High myopiaor extreme nearsightedness causes ophthalmic complications such as subcapsular opacities and increased risk of retinal detachment.Retinitis pigmentosa causes degeneration of the retinal cells, and Stickler syndrome characterized by facial and eye anomalies, precedes the formation of generalized subcapsular lens opacities. Myotonic dystrophy, Neurofibromatosis type 2, Diabetes mellitus, Hypoparathyroidism, alcohol abuse, and smoking may cause vascular endothelial damage hence are also implicated in cataract etiology.
- Toxic: Cataract has also been reported to be initiated byinjuries caused by chemicals such as naphthalene, thallium, lactose, galactose. Subcapsular opacities in the posterior region can be caused by corticosteroids and anteriorly by anticholinesterase inhibitors.
- Traumatic: Unilateral cataract in young patients is seldom traumatic. Perforating trauma or ablunt traumacan cause a flower-shaped opacity.Electric shock is a rare cause of cataract, forming numerous snowflakes opacities in the lenses. Therapeutic ionizing radiation used for ophthalmic andcardiological interventions may predispose tosubcapsular opacities formation.
- Nutritional: Associated with a diet with poor nutrition.Lack of vitamins, minerals and anti-oxidants deprive the lenses of their proper nutrition, leading to dryness and opacity.
Signs and symptoms of Cataract::
- Blurry vision: gradual progressive decrease in vision which is not rectified by the use of glasses
- Cloudy vision: caused by improper refraction by the opacities in the lenses
- Diplopia or double vision: the clear region interspersed among the opacities lead to variable refraction
- Coloured halos: water droplets captured between the lens fibers act as a prism and split light rays into its subordinate frequencies forming coloured or rainbow halos around the light
- Change in vibrancy: this disturbance in refraction of colours cause yellowing or fading of light
- Glare: increased sensitivity to bright lights such as that of the vehicles
- Diminished visual acuity
Diagnosis of Cataract
- Visual acuity: Evaluates the impact of refractive errors on the divergence of narrow-angle light. Snellen chart is the standard aid used for recording refractive errors. The smallest line read by the patient is expressed as a fraction. The numerator refers to the distance of chart from the patient which is approximately 6 meters and the denominatormentions the distance at which a person with no vision impairment is supposed to clearly see the chart.
- Slit-lamp examination: It is used to evaluate ophthalmic pathologies based on backscatter assessments. Patient is supposed to sit on a chair placing his/her chin on the support of the machine. It assesses the afferent and efferent visual pathways based on the dilated pupillary responses. It also evaluates the condition of cornea so as to estimate its ability to sustain ophthalmic interventions. Examination of the lens and volume assessment of the anterior chamber of eye is crucial as a shallow anterior chamber and lens defects may complicate a cataract surgery. Additionally, this technique also examines the fundus, the status of which is critical in the determination of visual outcome after surgery.
- Cover test: It is used to assess the deviation of lens. Lens maladjustment following vision defects caused by cataract can lead to a divergent squint.
- Tonometry: It is a technique of measuring the intraocular pressure in order to rule out glaucoma. A puff of air or pressure is exerted into the patients’ eye and changes in intraocular pressure are measured.
- Ophthalmoscopy: this technique check for optic nerve damage. Using a hand held device light is shown into the patients’ eyes to magnify the optic nerve and check for abnormalities.
- Biometry: It is the method of evaluating the power of lens by measuring the power of cornea in relation to the eye length. It provides with an estimate of the lens power best suited for optimum refraction following cataract surgery.
Types of Cataract
Based on location:-
- Nuclear sclerosis:It is the predominant type of cataract located in the central region of lens. Opacities in the nucleus of lens tend to change in color with progression of cataract, becoming yellow and gradually brown and dark. Flexibility of the leans is lost making it stiff and leading to gradual vision loss. Nuclear opacities are evaluated based on its intensity to scatter light rays at the nucleus.
- Cortical cataract and subcapsular opacities: Less commonly opacities may form in the cortex or the outer surface of the lens that envelope the nucleus. The type of cataract bears a resemblance to a spoke wedging inwards into the nucleusscattering the light rays hitting the retina, and are referred to as aggregates. These cortical opacities are evaluated by measuring the area of opacities in a zone of maximum dilation of pupil. The most common symptom associated with cortical cataract is glaring of light rays.
- Posterior subcapsular cataract:This type of cataract is predominantly seen in diabetic retinopathy and corticosteroids over or prolonged use. Dull opacities are forms at the posterior surface of lens which cause glaring of light rays as well as difficulty in reading. They often show a rapid progression, thus early indication of symptoms. Posterior subcapsular opacities are evaluated based on thepercentage of extensions as seen in normal pupil, moderately dilated pupil and a maximally dilated pupil.
The treatment protocol for all the three types of cataract is surgical intervention.
Stages of Cataract
The Lens Opacity Classification (LOC) system was developed for ophthalmic epidemiological surveys indicating cataract progression.
- Nuclear sclerosis is a measure of opalescence and sclerosis of the lens nucleus.
- Cortical cataract (CC) and subcapsular opacities are quantified based on the area occupied and expressed in percentage.
- Posterior subcapsular cataract (PSC) is a measure of posterior capsular area obscured, also expressed in percentage.
Based on these values the grades are:
- Grade I: Mild nuclear sclerosis, cortical aggregates block 10% of intrapupilary space, posterior subcapsular cataract occupy 3% of the posterior capsule
- Grade II: Moderate nuclear sclerosis,cortical aggregates block 10-50% of intrapupilary space, posterior subcapsular cataract occupy 30% of the posterior capsule
- Grade III: Pronouncednuclear sclerosis,cortical aggregates block 50-90% of intrapupilary space, posterior subcapsular cataract occupy 50% of the posterior capsule
- Grade IV: Severenuclear sclerosis,cortical aggregates block>90% of intrapupilary space, posterior subcapsular cataract occupy>50% of the posterior capsule
Treatment of Cataract
Patient is instructed to stop wearing contact lens for a minimum of two weeks prior to the surgery due to the risk of distortion that interferes with the selection of appropriate size of intraocular lens. Topical medication is given to the patient preoperatively to cause pupillary dilation. Topical anesthetics are injected before the surgical procedure. Surgery is performed via an ophthalmic surgical microscope.
- Phacoemulsification (PE): A small trapdoor incision is made in the sclera or cornea approximately 2.5cmm wide. Configuration of the incision is crucial in conserving the self-sealing quality of the wound.Ophthalmic viscosurgical devices (OVDs)are injected into the eyes, anterior chamber. The purpose of OVDs is to maintain the volume of the eye by preventing deflation of the globe and provide protection to the deeper vital structures. An ultrasound probe is introduced into the anterior portion of lens capsule, which is fragmented;and subsequently the fragments are emulsified within the eye. The lens contents are aspirated with the probe, with the capsular bag remaining intact to receive the intraocular lens (IOL). As this procedure requires an incision wide enough for only the probe to enter the eye, hence a small triplanar wound suffices the procedure. After the extraction of cataract, an IOL customized according to the patients’ dioptric power is placed in the posterior chamber of eye. In case of phacoemulsification, the IOL is made up of acrylic which is also foldable. In most of the cases, sutures are not required for wound closure, hence termed as stitchless cataract surgery. This prevents any distortion caused by the sutures at the corneal edge. Consequent development of astigmatism is also negligible. Following phacoemulsificatin, visual rehabilitation is expeditious.
- Manual small-incision cataract surgery (MSICS): A similar triplanar incision as done in phacoemulsification, is made. Shape being the same, the difference in the incision lies in its size, as here the incision is wider approximately 8-9mm, which is made only in the sclera. The increase in width of the incision allows the lens to be extracted through it. Capsulotomy performed can be either linear or continuous curvilinear. Multiple puncture marks are made in case of linear capsulotomy. An adequate portion of the superior part is salvaged to support the IOL. Viscoelastic is injected to push back the posterior capsule and then the nucleus and soft cortical lens are extracted, followed by the placement of a customized IOL. The IOL used in this procedure is made up of polymethylmethacrylate, that is quite rigid in contrast t the one used in phacoemulsification. The triplanar configuration provides the technique the benefits of self-sealing properties. As suture placement is not required, vision restoration is rapid.
- Extracapsular cataract extraction (ECCE): A 10-12mm wide incision is placed at the limbus in a biplanar configuration. Following anterior capsulotomy, the nucleus is extracted from the capsular bag and removed in toto. The remaining cortical lens is aspirated by irrigation and acustomized IOL paced. Similar to MSICS, a rigid IOL made up of polymethylmethacrylate is used. As the procedure involves a biplanar entrance, hence the incision made is broader and requires the placement of sutures for wound closure, leading to risk of complications, such as suture-induced astigmatism and irritation of the eye. These complications might act as focus of infection and prolong the process of visual rehabilitation.
An antibiotic solution is injected at the end of the procedure to prevent post-operative development of endophthalmitis.
Complications of Cataract surgery
- Disease related complications of congenital cataract: corneal ulcer, corneal perforation.
- Surgery related complications of congenital cataract: uveitis or inflammation of the middle layer of eye; posterior capsular thickening; glaucoma, an optic neuropathy; and retinal abnormalities which show increased risk of development in severe cataract cases.
- Disease related complicationsof acquired cataract: Phacolytic glaucoma wherein ahypermature cataract causes leakage of contents leading increased intraocular pressure; Phacomorphic glaucoma wherein a mature cataract exerts the anterior chamber, leading to an increase in intraocular pressure; subluxation of the lens; blindness.
- Surgery related complications of acquired cataract: Intraoperative- posterior capsular rupture the prevention of which is the prime concern during surgery, expulsive hemorrhage, hyphaema or the formation of blood clot in the anterior chamber of eye, and corneal burns. Post opearative- Iris prolapse or protrusion, delayed anterior chamber formation, infections like endophthalmitis or panophthalmitis, malpositioning of IOL, pseudophakic glaucoma, dysphotopsia a condition where halos are seen around the light source, ptosis or drooping of eyelids, and retinal detachment.
Am I a good candidate for Cataract surgery?
In conditions where cataract impedes with the day to day functional activities, and the use of glasses provide no relief in vision, it is indicated that the patient consider cataract surgery. Untreated aging-related cataract cause consistent vision deterioration in 60-70% of the patients. The timing of surgery is guided by the visual needs of individual patients. Senile cataracts are resolute and non-regressive, hence adequate visual correction by surgical interventions is necessary. Delay in surgical intervention can cause the cataract to become denser seen as a rigid dark opacity or the cataract may become mature and appear whiter. This stage of cataract warrants immediate emergency surgery as a last resort to restore vision. Indication for surgery is based on the interpretation of Snellen visual acuity test. If visual acuity falls below 6/24, then a surgical intervention is opted.
Cataract surgery Recovery time and after care
On the operative day, the patient might feel some hindrance in the eye giving a feel of sand in the eye, which is normal and will gradually subside in a few hours or days. Patient is instructed to be cautious to not rub the eye, and any discomfort should be relieved by prescribed antibiotic or steroid eye drops. Avoid getting shampoo and sweat in the eye. Protecting the surgically treated eye from ultraviolet damage is of utmost importance; hence patients are prescribed dark glasses to be worn postoperatively. Patients experience improved visual acuity from the first day onwards. It may take on an average a month for the eye to heal completely. Correction of spectacle lens is required following surgery.
Success rate of Cataract surgery
Excellent prognosis has been observed in as many as 70 to 80% of patients with effective restoration of vision. Outstanding results are seen if the patient strictly follows the postoperative instructions and medication routine prescribed by their ophthalmologist.
Benefits of Cataract surgery
- Increase range of age-adjusted mortality
- As cataract is a progressive debilitating disease, surgical intervention is necessary to restore vision
- Improves functional life
- Enhanced quality of life
- Preforming daily activities with ease
Cost comparisons of Cataract surgery
Cost of cataract surgery is dependent on certain variables such as: state of visual impairment, type of cataract diagnosed, stage of cataract at which patient approaches the ophthalmologist, unilateral or bilateral presentation cataract, type of surgical intervention required, associated systemic diseases and conditions. Phacoemulsification may cost between $550 to $700, while the newer surgical techniques might range up to $3000. Associated optic disease may cost an additional $400.
Why choose MedcureIndia?
Cataract surgery is the most commonly performed ophthalmic procedure and here at MedcureIndia, cataract surgical interventions are performed as day care procedures. Though cataract surgery is a routine procedure performed at most of the hospitals, selection of the surgeon is of utmost concern for the patient. We have a highly proficient team of professionals working together with the veterans in ophthalmology. We provide painless and hassle-free treatment and the patient can resume their functional life on the same day. Patients are strictly educated regarding the precautionary measures and medical instructions to lead a healthy life.