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Blurred Vision and Beyond: Understanding Common Eye Problems
Near-sightedness (myopia), far-sightedness (hyperopia), Astigmatism and Cataract are common eye problems for blurred vision. Similarly, various eye surgery has been developed to enhance vision.
Near-sightedness (Myopia):
This occurs when the eyeball is elongated, this shape causes light entering the eye to focus in front of the retina instead of directly on it. Myopia is an eyesight problem where one can see close objects clearly, but objects that are far away appear unclear. This can happen if the cornea (the clear front surface of the eye) curves too much, and it can also cause light to focus in front of the retina.
Far-sightedness (Hypermetropia/Hyperopia):
This occurs when the eyeball is too short, this shape causes light entering the eye to focus behind the retina instead of directly on it. Hyperopia is an eyesight problem where one can see far away objects clearly, but close objects appear unclear. This can happen if the cornea is too flat, it can cause light to focus behind the retina.
Astigmatism
Astigmatism is a common eyesight problem caused by an irregular shape of the cornea or lens. Instead of being normal spherical shaped, the cornea or lens is more football-shaped or cylindrical. This irregular shape prevents light from focusing properly on the retina, resulting in blurred or distorted vision in both near and distance unlike myopia and hypermetropia.
Cataract
Cataract is an eye inability to see due to a clouding of the eye’s natural lens often due to ageing. The cloudy refers to the lens of the eye becoming opaque or hazy rather than clear. Normally, the lens is transparent, allowing light to pass through and focus on the retina. When a cataract forms, proteins in the lens begin to clump together and form cloudy areas, which obstruct and scatter light and lead to impaired vision.
All four conditions can be corrected with glasses, contact lenses, or refractive surgery.
LASIK, PRK, and More: Eye Surgery Choices for Perfect Vision
There are several surgical options available for correcting blurred vision, primarily aimed at addressing refractive errors like myopia, hyperopia, and astigmatism having common surgeries to treat.
LASIK (Laser-Assisted In Situ Keratomileusis)
The Surgeon uses a microkeratome ( precise surgical instrument) or a femtosecond laser to create a thin covering in the outer layer of the cornea. The surgeon gently lifts the covering to expose the underlying corneal tissue.
A laser reshapes the irregular corneal tissue underneath the covering. This laser removes tiny amounts of corneal tissue to correct the refractive error. This reshaping allows light entering the eye to focus properly on the retina, improving vision. After reshaping the cornea, the surgeon carefully repositions the covering. The covering adheres naturally without the need for stitches.
Vision improves rapidly, often within a few days.
Not everyone is a suitable candidate; factors such as corneal thickness, overall eye health, and stable vision prescription are considered during the evaluation.
- Benefits:
- Widely performed and popular due to its quick recovery time and effectiveness.
- Suitable for correcting both myopia and hypermetropia.
- High success rate with minimal complications
- Recovery:
Vision improves rapidly, often within a few days.
- Cost:
₹30,000 to ₹1,00,000 per eye
Standard LASIK is generally less expensive than advanced forms like Custom LASIK or Wavefront-guided LASIK.
Candidates should be at least 18 years old with stable vision for at least one year.
PRK (Photorefractive Keratectomy)
A special brush, blade, or alcohol solution gently removes the thin outer layer of the cornea (epithelium).
An excimer laser, that uses ultraviolet B radiation to reshape the underlying corneal tissue by removing microscopic amounts of tissue. This reshaping corrects the refractive error by allowing light to focus properly on the retina.
A soft contact lens is placed on the eye to protect it as the epithelium regenerates over the next few days. The epithelium usually heals within a week. After the epithelium has sufficiently healed, the contact lens are removed.
- Benefits:
- Unlike LASIK, PRK does not involve creating a corneal covering, which eliminates the risk of complications.
- Doctors often recommend PRK for patients with thinner corneas who may not be suitable candidates for LASIK.
- Recovery:
Full visual recovery can take a few weeks to a few months.
- Cost:
₹20,000 to ₹70,000 per eye
Slightly less expensive than LASIK; the cost may vary based on the technology used
Advisable for individuals over 18 with stable vision for at least a year and without significant eye diseases.
SMILE (Small Incision Lenticule Extraction)
A surgeon performs a minimally invasive laser eye surgery primarily to correct myopia (near-sightedness) and, in some cases, astigmatism. Compared to LASIK and PRK, this relatively newer procedure has gained popularity due to its precision and quicker recovery times.
A femtosecond laser is positioned over the eye, and a lid speculum holds the eye open. The femtosecond laser creates a small, disc-shaped piece of tissue (lenticule) within the cornea The same laser makes a small incision (about 2-4 mm) on the surface of the cornea. The surgeon removes the lenticule through the small incision. This removal changes the shape of the cornea, correcting the refractive error
- Benefits:
- SMILE involves a small incision without creating a covering on the corneal , reducing the risk of related complications.
- It recovers faster and less postoperative discomfort like pain, dryness of eye compared to PRK.
- The structural integrity of the cornea is better preserved, which can be beneficial for patients with dry eyes or active lifestyles.
- Recovery:
Complete recovery and stabilisation of eyesight can take a few weeks to a few months.
- Cost:
Typically ranges between ₹50,000 and ₹1,20,000 per eye.
Advisable for individuals over 18 with stable vision for at least a year
The success of SMILE highly depends on the surgeon’s skill and experience
Overall, SMILE is an effective and advanced option for vision correction, offering several advantages over traditional procedures like LASIK and PRK, especially in terms of preserving corneal integrity and reducing recovery time
LASEK (Laser-Assisted Subepithelial Keratectomy)
The procedure combines elements of both LASIK and PRK and often suits patients with thin corneas or other conditions that make them less suitable for LASIK. Unlike LASIK, which creates a covering above the corneal tissue, LASEK involves loosening and gently lifting the outer layer of the cornea (epithelium) using an alcohol solution or a specialised brush.
Surgeons use an excimer laser to reshape the corneal stroma (the layer beneath the epithelium) to correct the refractive error.
The laser removes precise amounts of corneal tissue to adjust the way light is focused on the retina. The epithelial layer is carefully relocated over the treated cornea.
A protective contact lens is placed on the eye to aid healing and protect the epithelium. The protective contact lens is typically removed after a few days once the epithelium has healed
- Benefits:
- Since LASEK does not involve creating a corneal covering, it may be a better option for patients with thin corneas or other corneal issues.
- LASEK has a long history and is a well-established procedure for treating refractive errors.
- Recovery:
Complete visual recovery can take several weeks to a few months, as the corneal epithelium regenerates and the vision stabilises.
- Cost:
Typically ranges from ₹30,000 to ₹80,000 per eye.
Suitable for individuals over 18 with stable vision for at least a year and those with thin corneas or other specific conditions that make LASIK unsuitable
ICL (Implantable Collamer Lens)
Unlike LASIK or PRK, which involve reshaping the cornea, ICL surgery involves implanting a lens inside the eye to correct vision. A surgeon makes a small surgical cut, also known as an incision, usually at the extremity of the cornea. A surgeon inserts a biocompatible lens made of Collamer (a material that includes collagen) through the small incision.
The lens is positioned between the iris (the coloured part of the eye) and the natural lens. The lens is positioned in front of the natural lens, and the incision is usually self-sealing or may require a stitch.
- Benefits:
- With laser-based procedures, the ICL cannot be removed or replaced when necessary.
- Patients with thin corneas or high refractive errors are suitable for ICL placement, as the cornea remains unaltered.
- Recovery:
Full visual recovery and stabilisation can take a few weeks.
- Risks:
- Although rare, the lens can shift or become dislocated, which may require additional surgery.
- There’s a slight risk of increased intraocular pressure within the eye, which needs monitoring.
- Cost:
Typically ranges from ₹75,000 to ₹1,50,000 per eye
Suitable for individuals over 21 with stable vision and high refractive errors, or those who are not ideal candidates for LASIK or other laser procedures.
RLE (Refractive Lens Exchange)/ CLE (Clear Lens Extraction)
It is similar to cataract surgery but is performed on patients who do not have cataracts. Instead of removing a cloudy lens (as in cataract surgery), a clear lens is replaced with an artificial intraocular lens (IOL) to correct vision.
Using ultrasound, the natural lens is broken up and suctioned out through a small incision made in the cornea during phacoemulsification.
In this surgery, a insertion of an artificial intraocular lens (IOL) into the eye through the same incision is ex. The surgeon positions the IOL in the lens capsule, which holds the lens in place. The incision is usually self-sealing or may require a stitch, but it is typically very small and heals quickly.
- Benefits:
- RLE can correct a wide range of refractive errors and is particularly beneficial for patients with high degrees of myopia or hyperopia.
- It is effective in treating presbyopia, providing improved near and intermediate vision.
- Unlike LASIK or PRK, RLE does not involve reshaping the cornea, making it suitable for those with thin corneas or other corneal issues
- Recovery:
The eyesight get stable over the next few weeks to months
- Cost:
Cost of surgery varies from ₹70,000 to ₹2,00,000 per eye.
Suitable for individuals over 40, especially those with high refractive errors or presbyopia. A thorough eye examination is necessary to ensure that RLE is appropriate
RK (Radial Keratotomy)
RK is an eye operation that corrects impaired vision in myopia. One of the earlier techniques for vision correction was developed before the advent of laser-based procedures like LASIK and PRK. The surgeon makes a series of radial (spoke-like) incisions in the cornea using a diamond blade or surgical instrument.
These incisions alter the shape of the cornea, flattening it to correct the refractive error. The cornea heals naturally as the incisions close, which reshapes the cornea to improve vision.
- Benefits:
RK was one of the first eye surgery methods to correct myopia and is a non-laser technique.
- Recovery:
Full visual stabilisation can take several months. Some patients may need additional treatments or enhancements for optimal vision.
- Cost:
Typically ranges from ₹30,000 to ₹60,000 per eye.
Newer, more effective procedures such as LASIK, PRK, and SMILE have largely replaced RK due to their ability to provide superior results and fewer complications.
Cataract Eye Surgery: Restore Your Vision
Cataract surgery is an eye operational procedure to remove a cloudy, opaque lens from the eye and replace it with an artificial clear, transparent lens. There is no requirement for the admission of the patient in the hospital. The person can go home on the same day of operation.
The most common cataract surgery is phacoemulsification
Phacoemulsification
In this surgery, a small incision in the eye and uses an ultrasonic device to break up the cloudy lens into tiny fragments. The surgeon then suctions out these fragments and inserts an artificial intraocular lens (IOL). This method is favoured for its minimally invasive nature and quick recovery.
Extracapsular Cataract Extraction (ECCE)
This method involves a larger cut to remove the cloudy lens and replacing it with the IOL. In certain cases, this technique is needed instead of being less commonly used today.
Intracapsular Cataract Extraction (ICCE)
This older method involves removing both the lens and the surrounding capsule. Phacoemulsification is more commonly performed now due to its less invasive nature and shorter recovery time compared to it.
The choice of method depends on various factors, including the cataract’s severity, the patient’s overall health, and the surgeon’s expertise.
Reference
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2696744
https://link.springer.com/referenceworkentry/10.1007/978-3-319-90495-5_227-1
https://www.ncbi.nlm.nih.gov/books/NBK559253
Written by Rutuja Adake