Radial keratotomy vision induced vision blurriness has 3 main causes:
- Corneal Irregularity: A good redial keratotomy result would require that each incision be exactly the same length, the same depth, and placed perfectly in relation to the others. This can never happen with man-made incisions, so every single RK can surgical induced corneal irregularity. The incisions can never be removed, and they are not really scars even though some doctors call them that. What can be repaired is the irregularity that is caused by the incisions to make the anterior focusing surface of the cornea more normal again to minimize the scatter of light. The more irregular the cornea, the more light is scattered, the less homogenous the image on the retina in the back of the eye (which is like the “film” or the “digital light sensor” in the back of the eye. This is what causes multiple images, loss of clarity of vision, decrease in contrast, decrease in lines of vision visible on a chart, as well as the extensive night issues such as glare, halos etc. In medical and optical physics terminology these light scattering irregularities are called higher order aberrations (HOA).
- Refractive Error: The second problem with RK are the handmade incisions meant to weaken the cornea the collapse and flattening of the center. This is how myopia and astigmatism was treated with RK. The majority of patients end up with hyperopia and astigmatism, as the cornea flattens too much. When younger, the accommodation of the patient’s internal lens can help compensate for this hyperopia. The loss of this accommodative focusing capability of the natural lens as it ages is what causes the reading vision to worsen in patients. In patients with hyperopia from RK, it’s this loss that also makes their distance worse as well. We also have observed and theorized that the compensation centers of the brain’s optical area also seem to worsen at interpolating and compensation for visual flaws and scattered light as a person ages. In other words, the brain seems to get worse at compensating for the corneal irregularity caused by the RK.
- Fluctuations from natural internal ocular pressure change through the day: The third problem is the fluctuation that occurs throughout the day in RK patients. This is due to the natural diurnal pressure variation inside this eye. This variation in pressure can flex the cornea and change the refractive error in patients. If the other two problems are treated this usually becomes a small nuisance that is not difficult to tolerate.
Treatment options for RK center solve different issues for different treatments.
- Any sort of internal lens surgery such as lens exchange, cataract surgery, or ICL will not improve the irregularity of the cornea, it will only treat the refractive error similar to a pair of glasses (but a better as the induced aberrations from glasses are not present). Normal LASIK/PRK wavefront optimized, or wavefront guided laser vision correction surgery does the same exact thing as well- it only treats the refractive error. If a patient does not have a high level of corneal irregularity from the RK, i.e. the incisions were placed made and placed more evenly, then correction of the refractive error by these treatment modalities will help the vision significantly.
- Treatment of the corneal irregularity can either be done with a hard scleral lens that creates a new artificial surface, or by topography guided laser ablation. Topography mapping is used to generate a micron (1000th of a millimeter) by micron map of the irregularity of the cornea, and each high or low area is treated micron by micron by an excimer laser to create a smoother, more uniform surface. At Cornea Revolution we have taken this type of treatment a significant step further by also mapping and treating the compensation of the surface epithelium (the clear skin layer) that can prevent the topography system from seeing the full extent of the corneal irregularities. The results of this dramatically increased the removal of HOA from 52% to 68% in a peer reviewed published clinical study by Dr. Motwani.
https://drmotwani.com/radial-keratotomy-rk-repair/
https://drmotwani.com/nuclarityvision/
- Significant fluctuations are usually treated by checking morning and afternoon refractive errors, and treating refractive error right in between the two measurements to minimize the impact of the fluctuations.
These are the mainstays of treatment, but be aware some doctors try to present some of these treatments in their own marketing speak without any valid published, peer-reviewed scientific data to support how their procedures are in any way superior. The FDA in the United States, as well as other regulatory bodies around the world, only allow certain types of procedures to be performed and certain types of devices to be used. Please be careful of treatments that don’t have valid accessible scientific data to support them.
https://cornearevolution.com/publications
https://drmotwani.com/dr-manoj-motwani/
This newly reshaped cornea is “frozen” into place with corneal cross linking, for a virtually permanent repair to the cornea. The cornea stops progression from keratoconus as is well documented with corneal cross linking in keratoconus and corneal ectasia, and stays in the new normalized shape indefinitely.
