Laser blended vision

Laser Blended Vision, is a sophisticated laser eye treatment which is used to treat presbyopia (ageing eyes)]] (progressive loss of the ability to focus on nearby objects) or other age-related eye conditions. . It can be used to help people that simply need reading glasses, but also those who have started to need bifocal or verifocal spectacle correction due to ageing changes in the eye. It can be used for people who are also short-sighted (myopia) or long-sighted hyperopia and who also may have astigmatism.

Primarily the treatment is for condition called presbyopia Blended vision can be achieved through laser eye surgery such as LASIK, PRK or LASEK, by increasing the depth of field of each eye through subtle changes in the optics of the corneal spherical aberration. The increase in depth of field allows for the eyes to be corrected in such a way that the dominant eye is set for distance and intermediate vision while the non-dominant eye sees best in the intermediate to near range. Because of the similarity in the visual performance of each eye in the intermediate range the brain is able to fuse the images between the eyes rendering a binocular visual environment. This is in contradistiction to traditional monovision where the image disparity between the eyes is too high for image fusion by the brain and instead the brain needs to apply suppression of the blurred eye in order to perceive a clear visual field. In Laser Blended Vision, the eyes are effectively working together to allow good vision at near, intermediate and far, without the use of glasses. The effects of Laser Blended Vision tend to laset between 5 to 10 years but can be further adjusted by enhancement procedures.

Advantages of treatment
Laser Blended Vision provides a range of benefits, particularly in comparison to tradition monivision solutions, such as bifocal glasses or contact lenses.

The key advantage of laser blended vision is the freedom from reading glasses. Over 98% of laser blended vision patients can read normal newsprint and over 90% can read the small print on medicine bottle inserts.

There is a creation of intermediate and far-intermediate distance zone of fusion, allowing the merging of images from each eye in the brain so no dissociation between the eyes. And due to increased depth of field in both eyes, the vision is significantly better than would otherwise be anticipated.

The technology of the excimer laser provides maximum safety particularly as the eyetracker’s feedback frequency is higher. The laser treatment is a comfortable and gentle procedure and provides an extremely rapid rate of recovery.

Preoperative Screening
During the preoperative screening, a complete examination of the eye is carried out at a consultation with the surgeon to determine if a patient is suitable for laser blended vision treatment. The dominant eye is determined and vision tested to identify the level of correction required for distance and near on the dominant eye and non-dominant eye. The analysis of ocular dominance also allows for ensuring the eyes can work together to create the blended vision.

During Surgery and Post Operative
During the surgery, a corneal flap is created, during which there can be a sensation of slight pressure on the eye during the procedure.

The left eye is covered and the right eye is opened and kept open by a speculum, the corneal flap is lifted and the laser correction is done – an ultra thin flap can be created for treatment of very high prescriptions. The flap is replaced and the speculum is removed. The left eye is treated next. The software data given to the Zeiss MEL 80 laser stores all the details of the dominant eye and what correction has to be done for each eye. The laser time for each eye is usually under 30 seconds.

During the laser refractive surgery, the dominant eye is mainly corrected for distance vision and the non-dominant eye is corrected for near vision, whilst also increasing the range of focus for each eye.

The entire procedure takes approximately 20–30 minutes and the visual recovery is rapid and there is very little pain afterwards. The recovery period post operative usually is between 24 hours and 7 days. Care is needed to not rub eyes and to wear eye shields during the night. The results are almost instantly available to the patient, where objects and people will seem more in focus.

Suitability of treatment
Laser blended vision treatment is suitable for people suffering from presbyopia. People mostly suffer from presbyopia, refractive error between the ages of 40–45 years. It occurs when the natural eye lens becomes less elastic and the muscle that pulls it into focus becomes less powerful as we age. In the young eye, the muscles contract to relax the ‘jelly like’ lens, changing its focal point to allow for distances and near focus. As we get older, our lenses continue to grow and layers of fibers are laid down making the lens less flexible.

Treatment results
Patients treated using laser for blended vision, have an increased depth of field compared to traditional monovision. There is a diminishing effect of the depth of field with use of contact lenses.

According to a study conducted by Dr. Dan Reinstein, more than 95% of patients he treated tolerated Laser Blended Vision, compared with only 59% to 67% of patients who tolerate contact lens monovision.

After a year of the laser treatment, 94.5% of patients achieved 20/20 vision.

Limitations and potential complications
The aim of this surgery is to produce one eye that sees objects close up, whilst the other sees objects that are far away. This can produce problems initially, as you may feel dizzy or nauseous until your brain adjusts to this new method. This is usually quickly, as the brain begins to ‘blend’ the images from both eyes together, to produce corrected vision. As with all laser eye procedures, there are risks and side effects of the treatment. You should understand these before you decide to go ahead.

The Excimer laser enables safe treatment of higher levels of myopia, and provide accurate calibration. After the laser surgery, one may require artificial tears and antibiotic eye drops which can caused blurred vision temporarily. Dryness of eyes can be a little uncomfortable for a few weeks after the surgery.

Presbyopia is progressive and therefore a boost maybe required after some years. Typically the effects of laser blended vision surgery can last between 5–10 years.