Laser Cataract Surgery
Cataract is the opacification of natural clear lens. As a part of treatment, cataract has to be removed and replaced with an artificial intraocular lens. Cataract surgery is a process of removal of cloudy lens. Change is the only constant thing in this world. As the science advances, method for removal cataract is getting better and better. Veteran ophthalmologist had seen transformation from Intracapsular cataract surgery to extracapsular cataract surgery. They have witnessed first generation phacoemulsification machine & also the most advanced phaco machine with advanced fluidics. As the technology is taking leap towards next milestone, it has benefitted patients in terms of better visual outcome and surgeons in terms of ease of performing the skilled procedure.
Phacoemulsification is a procedure in which surgeon makes small incisions with help of blade to enter the eye and cataract is removed with the phacoemulsification probe. Surgeon uses ultrasound energy to dissolve cataract. Traditional phacoemulsification procedure is highly skilful surgery, very much dependent upon surgeon’s dexterity, experience and volume of surgeries one has performed.
In laser assisted cataract surgery, an advanced femtosecond laser replaces or assists use of a hand-held surgical tool for the following steps in cataract surgery:
1. The corneal incision
2. The anterior capsulorrhexis
3. Cataract fragmentation
Use of a laser can improve the precision, accuracy and reproducibility of each of these steps, potentially reducing risks and improving visual outcomes of cataract surgery.
1) Corneal incision:
Self-sealing corneal incision by keratome/ Diamond blade is the first step in cataract surgery, it allows surgeon to gain access to the interior part of the eye. It is made in the periphery of cornea (i.e. limbus). In laser cataract surgery, the surgeon creates a precise surgical plane for the corneal incision with a sophisticated 3-D image of the eye called an OCT scan. The goal is to create an incision with a specific location, depth and length in all planes, and with the OCT image and a femtosecond laser, it can be performed exactly. Creation of corneal incision with laser is independent of surgeon’s experience.
In traditional cataract surgery, central and round opening is made in the front portion of the capsule (capsule is a bag which holds natural lens) is made with the help of 26 g needle or capsulorrhexis forceps (utrata forcep). Rest of the bag is left behind which supports IOL after removal of cataract. So capsulorrhexis is totally dependent on surgeon’s skills for its centration, size etc. In laser cataract surgery, the anterior capsulotomy is performed with a femtosecond laser. Studies have shown that capsulotomies performed with a laser have greater accuracy and reproducibility but tensile strength of opening slightly less than that of surgeon made opening. In summary, though reproducibility and accuracy is more when opening is made with Femtosecond laser; as far as strength of opening is concerned it is no where near to the manually performed capsulorrhexis. Weak opening can create problem in placing IOL in the CAPSULAR BAG.
3) Cataract fragmentation:
In routine cataract surgery; after capsulorrhexis, surgeon breaks nucleus with help of phacoemulsification probe using ultrasound & mechanical energy. Depending upon grade of cataract, energy used to emulsify cataract in the eye differs. Hard cataract requires more energy so consequently there is more collateral tissue damage as compared to soft cataract. Experienced surgeon takes all precaution to minimise such tissue damage. In femtosecond laser assisted cataract surgery, on the other hand, laser softens the cataract as it breaks it up. By breaking up the cataract into smaller, softer pieces, less energy is needed to remove the cataract. So even in laser assisted cataract surgery, phaco probe needs to be inserted inside eye after application of femtolaser on cataract but this time, probe can emulsify pre-cut pieces with less energy as compared to conventional phaco procedure. The reduced phacoemulsification energy required in laser cataract surgery may also make the procedure safer to the inner eye, which reduces the chance of certain complications, such as PCR (Posterior capsule rent).
These days, surgeon gives some relaxing incision (Limbal Relaxing Incision) over cornea to reduce corneal astigmatism (i.e. intrinsic glass number that patient may need after surgery due to curvature of cornea). During refractive laser-assisted cataract surgery, the OCT image can be used to plan laser LRI or AK incisions in a very precise location, length and depth. This increases the accuracy of the astigmatism-reducing procedure and increased the probability of good vision without glasses after cataract surgery.
Cost of laser cataract surgery is way higher than the conventional phaco procedure as the cost of femtosecond laser machine & its maintenance is huge. There are few conditions where laser assisted cataract surgery can’t be performed like small pupil and corneal scar etc.
It is important to put this newest technology into proper perspective. Routine phacoemulsification cataract surgery is very effective and successful at the hand of experienced surgeon. People who do not want to invest so much money in laser assisted cataract surgery can still feel confident about the routine phacoemulsification procedure. Experienced surgeon can deliver visual outcome at par with laser assisted cataract surgery at much lower cost.
Laser assisted cataract surgery seems to be appealing but its cost effectiveness is questionable. To sum up, its more accurate incision, capsulotomy and astigmatic correction may help patient to achieve goal of less dependence on glasses after cataract surgery but at a higher price. However, in the hands of an experienced surgeon results with the routine phacoemulsification are even better that too at a fraction of a cost.