PHAKIC OR SILK, WHICH ONE IS RIGHT FOR YOU?

SILK and Phakic surgery are two advanced refractive surgeries, highly regarded for their safety, effectiveness, and optimal post-operative eye protection. Each surgical method has a distinct procedure, treatment range, as well as its own set of advantages and limitations.

So, which option is more suitable for refractive error correction SILK or Phakic? To help patients gain a clearer understanding of these two surgical methods, the following article provides a detailed comparison of their surgical procedure, treatment thresholds, expected outcomes, ideal candidates, and associated costs.

1. Procedure and Treatment Range of SILK and Phakic Surgery

SILK: SILK (Smooth Incision Lenticule Keratomileusis) uses an advanced Femtosecond Laser to carve out a lens-shaped biconvex lenticule inside the cornea based on proprietary technology from Johnson & Johnson, USA, and then extract that lenticule through a very small incision at the corneal periphery, helping restore optimal vision for the patient. 

SILK surgery is indicated for patients with myopia (with or without astigmatism) up to -12D, astigmatism up to -6D, with the total of myopia plus astigmatism ranging from -1.00D to -12.00D.

Phakic: 

Phakic surgery is a refractive treatment method that involves implanting a high-safety intraocular lens, custom-designed based on the individual measurements of each eye. The lens is placed behind the iris and in front of the natural lens, allowing for vision correction without reshaping or removing corneal tissue. This technique provides high-definition visual quality and is especially suitable for patients with high levels of myopia or astigmatism, particularly those with thin corneas who are not eligible for laser-based procedures.

Currently, there are two types of intraocular lenses used in Phakic surgery:

• ICL: Corrects up to 18.00D of myopia, 10.00D of hyperopia, and up to 6.00D of astigmatism.
• IPCL: Offers a broader treatment range up to 30.00D of myopia, 15.00D of hyperopia, and up to 10.00D of astigmatism.

2. Procedure duration and visual recovery time for SILK and Phakic

Surgery Duration

Both SILK and Phakic surgeries are quick procedures, typically taking around 10 to 15 minutes for both eyes.

For SILK, a procedure utilizing the latest generation of laser technology,  patients may undergo examination, surgery, and return home all on the same day if their eye condition meets the surgical requirements.

For Phakic surgery, since it involves the implantation of a personalized intraocular lens, the lens must be produced and shipped from overseas. The lens production and delivery process typically takes 5 to 7 weeks. After the procedure, patients are typically observed for 3–4 hours post-surgery before discharge.

In terms of surgical timing, SILK offers the advantage of a faster turnaround, while Phakic requires a longer preparation period due to the need for custom made lenses.

Visual Recovery

Both SILK and Phakic surgeries offer excellent visual outcomes, with vision quality comparable to the best corrected visual acuity achieved with glasses prior to surgery. However, due to the non-invasive nature of Phakic surgery,  which does not involve reshaping the cornea, patients often experience sharper vision in low-light conditions compared to SILK.

In terms of recovery time, both procedures typically allow patients to regain clear vision within 4 to 6 hours post-surgery. Most can resume normal daily activities after one day, engage in light physical activity after two weeks, and return to sports or more intense exercise after one month.

Regarding dry eye symptoms, Phakic surgery does not cause dry eyes as it does not alter the corneal structure. In contrast, SILK may cause mild dry eye symptoms, though at a significantly lower rate compared to previous generations of laser procedures. These symptoms are usually manageable with lubricating eye drops or artificial tears during the first 1 to 3 months after surgery.

Overall, both SILK and Phakic offer rapid recovery times, but Phakic holds an advantage in low-light vision and in avoiding dry eye issues.

3. Advantages and Disadvantages of the SILK and Phakic 

SILK Surgery

Advantages

SILK surgery is the most advanced refractive laser technology available today, utilizing the 5th-generation Femtosecond Laser with significant improvements in energy control, speed, and precision.

• Ultra-low laser energy (40–50 nJ):
• Minimizes damage to corneal tissue, helping preserve corneal structure and reduce the risk of post-operative complications.
• The low energy also limits thermal impact, helping to reduce inflammation and irritation after surgery.
• Smallest laser spot size (~1 µm):
• Produces a smooth interface in the stromal tissue, allowing the surgeon to operate with greater ease and precision while minimizing damage to surrounding tissue.
• This also helps optimize post-operative visual quality, providing patients with sharper, clearer vision.
• High-speed laser (10 MHz) with optimized surgery time (~16 seconds)
• The laser time is only around 16 seconds, helping to shorten the overall procedure time and reduce stress for the patient.
• The high pulse rate allows for more even energy distribution, minimizing thermal effects and lowering the risk of corneal irritation after surgery.
• The procedure is quick and precise, providing patients with a more comfortable experience and faster recovery.

In addition to its advanced laser technology, SILK features an exclusive bi-convex lenticule design, offering several advantages during surgery and recovery:

• It ensures even distribution of cutting forces, helping the cornea remain more stable after surgery, reducing the risk of corneal deformation, and preserving its biomechanical strength.
• The smoother cutting surface allows for easier lenticule extraction, shortening the surgeon’s handling time.
• It reduces postoperative haze by avoiding corneal folds, which are more likely to occur with single-sided (flat and curved) lenticule design. 

Limitations

Although SILK surgery is considered one of the most advanced laser treatments for refractive errors available today, there are still some limitations that patients should carefully consider before choosing this method:

• Not suitable for treating farsightedness

SILK works by removing a small lenticule from the cornea to correct refractive errors. This procedure is effective for nearsightedness and astigmatism but cannot alter the corneal curvature in the way required to treat farsightedness. Patients with farsightedness should consider alternative options such as LASIK or Phakic.

• Requires sufficient corneal thickness

For patients with thin corneas, this procedure may not be suitable. Removing the lenticule can reduce the cornea's structural strength and increase the risk of postoperative corneal deformation.

• May cause temporary dry eyes

Because SILK uses a femtosecond laser to remove corneal tissue, it may lead to mild dry eye symptoms after surgery, although the incidence is lower compared to earlier generation laser procedures. This condition typically lasts from 1 to 3 months postoperatively and can be managed with artificial tears and lubricating eye drops.

• Slight haziness in vision during the early recovery period

Due to the removal of the lenticule to correct refractive errors, some patients may experience mild haziness in their vision during the first few days after surgery. However, with SILK, this effect is often minimal thanks to the specially designed lenticule. The haziness is temporary and usually resolves on its own as the cornea adapts to the change.

PHAKIC

Advantages

• Preserves corneal thickness and natural eye structure

Unlike laser based procedures such as LASIK or SILK, Phakic surgery does not involve removing corneal tissue. This helps maintain the natural structure of the cornea, making it an especially suitable option for patients with thin corneas or very high myopia who may not be eligible for laser surgery.

• Minimizes risk of post-operative dry eye symptoms

Phakic surgery does not affect the cornea, and therefore does not interfere with the corneal surface nerves which is the main cause of dry eyes following laser refractive procedures.

• Sharper vision quality, even in low-light conditions

Phakic surgery provides clearer and more precise vision, especially in dim lighting or at night, thanks to the use of high-quality optical lenses. This helps reduce issues such as glare and halos that some patients may experience after laser procedures.

• Protects the eyes from UV rays, reducing the risk of retinal diseases

ICL lenses are made from Collamer, a material with excellent UV blocking properties that helps shield the eyes from the harmful effects of sunlight. As a result, Phakic surgery may help lower the risk of serious eye conditions such as early cataracts, macular degeneration, and UV-induced retinal damage.

Disadvantages

• Higher surgical cost

Phakic surgery typically costs between 90 to 100 million VND for both eyes, which is significantly higher than laser procedures like SILK or LASIK. This is mainly due to the fact that the intraocular lens is custom made for each patient, requiring advanced manufacturing technology and high-quality materials.

• Longer waiting time before surgery

Since the intraocular lens is custom made based on each patient’s specific measurements, there is typically a waiting period of 5 to 7 weeks from the time the lens is ordered to the actual surgery date.

• Risk of increased intraocular pressure after surgery

Some patients may experience a temporary rise in intraocular pressure shortly after surgery due to changes in the flow of aqueous humor within the eye. However, this condition can usually be managed with eye drops or medical intervention if necessary.

• Not suitable for all patients

To be eligible for Phakic surgery, patients must have a sufficient anterior chamber depth,  the space between the cornea and the natural lens, to ensure the intraocular lens can be placed safely.

4. Cost of SILK and Phakic Surgery

Currently, the surgical fees at Japan International Eye Hospital are as follows:

• SILK surgery: 55 million VND for both eyes
• Phakic surgery: 90–100 million VND for both eyes

All patients undergoing refractive surgery will receive a gift package worth 4.5 million VND, which includes:

• Comprehensive pre-surgery eye examination
• Eye drops and safety glasses
• 12 months of free post-operative check ups

Please note: Fees may vary depending on current promotional programs and hospital policies at different times. For the most detailed and up to date information, patients are encouraged to contact the hospital directly for consultation.

SILK and Phakic surgery are two effective solutions for correcting refractive errors, each suitable for different groups of patients.

SILK is an ideal choice for individuals with mild to moderate myopia, sufficient corneal thickness, and a desire for a modern, quick, and gentle surgical method. Meanwhile, Phakic is more appropriate for patients with high refractive errors, thin corneas, or those who are not eligible for laser-based procedures provided that the anterior chamber is deep and wide enough to safely accommodate the lens.

To ensure the most suitable treatment option, patients should consult with an experienced ophthalmologist, undergo a comprehensive eye examination, and receive a thorough evaluation of their eye condition before making a surgical decision.