We explain your vision,
prescription and options
for great vision.

Understanding Your Vision – Nearsightedness / Farsightedness / Astigmatism

Eye chart test measures visionThe key to understanding refractive surgery is to understand how the eye works. Once you’ve read about your vision below, check out what your prescription really means at the bottom of this page.

Normal Vision
Sharp, clear vision is the result of light rays passing through the cornea, pupil and lens of the eye and focusing directly on the retina. If the cornea is not round, or is too steep or too flat in relation to the length of the eye, light rays focus either in front of or behind the retina. This results in “refractive errors” such as nearsightedness, farsightedness, and astigmatism. Laser vision correction improves the way the eye focuses light by modifying the curvature of the cornea and re-focusing the light directly on the retina.

Nearsightedness
Nearsightedness, or myopia, occurs when the curvature of the cornea is too steep or the eyeball is too long. With nearsightedness, the eye’s strong refractive power forces the image to be focused in front of the retina, rather than on it. When light focuses in front of the retina, near objects can be seen clearly, but far objects appear blurry. Myopia can be treated by flattening the cornea with LASIK or PRK. An alternative non-laser procedure, Implantable contact lens (ICL) eye surgery, can correct myopia by implanting a special type of lens inside the eye.

Farsightedness
Farsightedness, or hyperopia, is caused when the curvature of the cornea is too flat or the eyeball is too short, forcing light to focus behind the retina. With farsightedness, the eye’s weak refractive power causes far objects to be seen more clearly and near objects to appear blurred. The eyes may have to strain to maintain things in focus. The first appearance of hyperopia is strongly age-dependent; younger patients have much less difficulty with hyperopia. Hyperopia can be corrected by steepening the central cornea with LASIK or PRK.

Astigmatism
Astigmatism occurs when the cornea is irregularly shaped – like a football or a teaspoon – preventing light from converging on the retina. Parts of the image may focus on the retina, while others focus behind it or in front of it. This has the effect of bending light inconsistently and causing blurred or distorted images. Astigmatism can occur alone or in addition to either nearsightedness or farsightedness. Although astigmatism can complicate refractive surgery, it can be effectively corrected with LASIK or PRK.

Higher-order Aberrations
Several types of visual imperfections, referred to as lower- and-higher-order aberrations, can exist within the same eye and affect both visual acuity and the quality of vision. Lower-order aberrations, like nearsightedness, farsightedness and astigmatism, contribute to approximately eighty percent of refractive errors and affect how much you see. Higher-order aberrations account for the remaining twenty percent of error and affect how well you see. They can be compared to smudges or spots on your glasses and have been linked to halos and glare that cause vision problems at night. In the past, higher-order aberrations have not been treatable by conventional laser vision correction procedures. Now, Contoura® Vision Topography-Guided LASIK can quantify and correct these higher-order aberrations.

Presbyopia
As people get older, the lens inside their eye changes and is no longer able to focus on images up close. This condition is called presbyopia or “reading glasses syndrome.” People with this condition may experience eye fatigue when reading in poor light or at the end of the day, have trouble changing their focus from distance to near, or need to constantly reposition reading material in an attempt to find the right focus. This loss of elasticity in the lens becomes apparent when near vision starts to get blurry somewhere between the ages of 40 to 50. This happens to everyone, regardless of whether they have ever worn glasses before. The symptoms of presbyopia are sometimes confused with those of farsightedness, but they are not the same and the treatment for each is different.

Traditionally, presbyopia has been corrected by wearing reading glasses. Some people have avoided reading glasses for many years, however, by having their vision corrected with LASIK or PRK and a technique called monovision. Additionally, presbyopic vision can also be corrected with non-laser vision procedures like Refractive Lens Exchange Surgery (RLE) that help reduce dependence on glasses or contacts.

Monovision
Monovision refractive surgeryMonovision is an option for people with presbyopia where each eye is adjusted to have a slightly different focus point. One eye will see things close up, the other eye will see things farther away – and the brain will integrate the visual information from both and filter out any blur. With monovision, you do not need to make any conscious adjustments in how to see and the brain usually adjusts within six to eight weeks.

Monovision refractive surgery is not a cure for presbyopia. It simply “re-sets” the clock for near vision, giving you an additional 5 to 10 years without the need for reading glasses for most tasks. Even with monovision, however, there may be some situations (such as night driving in unfamiliar areas) where you might require glasses.

The decision to have monovision refractive surgery is dependent on your age, profession, hobbies and desires. People who need to see very well at distance (e.g., pilots or nighttime truck drivers) may not be the best candidates for monovision. It’s also not recommended for people under 40 who are not yet feeling the effects of presybopia because the benefits will not be realized for many years. It is possible that surgeries that directly cure presbyopia will become available in the future.

It is a good idea to simulate monovision on a trial basis to see if you are comfortable with your eyes focusing at different distances. We can help you do this by fitting you with contact lenses or trial eyeglass frames adjusted to reflect the different possible corrections. This will give you a good idea of whether monovision is right for you.

Monovision has been used successfully for over 20 years. Refractive surgery patients can achieve monovision either with LASIK or PRK. If monovision testing is inconclusive as to whether you would benefit from the procedure, RLE Surgery may also be an option.

Vision correction surgery gets rid of glasses for most prescriptions
Which of these is true for you? You might benefit from monovision with LASIK / PRK You might benefit from IOL Surgery
I only need reading glasses 65 and under
I had LASIK before and now need reading glasses 65 and under
I use bifocals or progressive lenses 50 and under Over 50
My prescription is outside the LASIK parameters Over 50
I am noticing impaired night vision, depth perception and/or color distortion All ages

Understanding Your Prescription

When you go to the eye doctor for glasses or contact lenses, the doctor measures your eyes and records these readings in a prescription. Patients have a tendency to remember that they are “20/400” or “20/1000,” but these numbers simply refer to the line on the eye chart that you are able to read. Doctors use a more precise set of numbers to measure your prescription.

If you look at your prescription, either for glasses or contact lenses, you can get a fairly good idea as to the type of refractive error that you have, as well as its severity. Generally, prescriptions appear as a series of three numbers and might look something like this:

Example Prescription
RX SPH CYL AXIS
RIGHT EYE -2.50 -1.00 180
LEFT EYE -4.25 -1.25 93

The first number (sphere) indicates the curvature of the cornea. A negative number means that you are nearsighted with a cornea that is too steep. A positive number means that you are farsighted with a cornea that is too flat. The closer the number is to zero, the less severe the prescription. The second number (cylinder) indicates the amount of astigmatism you have. The further the number is from zero, the more pronounced the astigmatism. A value up to 2.50 is considered moderate; anything above 2.50 may be considered severe. The third number (axis) reflects the orientation of your astigmatism.

LASIK or PRK can treat the widest range of prescriptions from  -14 through +6. For those patients with prescriptions outside this range, we offer additional vision correction options including ICL or RLE.  The graphic below depicts the treatment options based on prescriptions.

Vision correction procedure for the range of prescriptions

Range of Prescription

Lori T.
San Jose, CA

9/6/2020
Yelp

The whole process of my lasik journey from start to finish at Furlong was amazing! They have taken the necessary covid precautions to ensure that you & the staff are entirely safe. I'm 2 days postop and I love my new eyes! It's the best investment money can buy! Thank you to the entire Furlong team! I couldn't be happier with the results. 

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Rachel T.
San Francisco, CA

8/8/2020
Yelp

i chose to go with furlong because i have friends who've gone to him and had really good experiences. when it comes to my eyes and quality of vision for the next 20 years, i'm willing to pay for security and quality…i was able to use hsa to pay so that's definitely helpful. i had a great experience overall and i hope this review is helpful for anyone who's unsure!

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Kristin B.
San Jose, CA

8/1/2020
Yelp

I'm thrilled! Just had my surgery yesterday and woke up with perfect vision. Everything is meticulously clean here. I started before COVID and had surgery during COVID. Very impressed with how this office quickly adapted to necessary health precautions and kept on providing excellent service. Dr Sane did my surgery. She explained everything, including during the surgery.

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Seneca K.
San Jose, CA

6/4/2020
Yelp

I've had such a positive experience at Furlong and I will recommend them to everyone! I've had a few consultations at various places and Furlong was the only place where I felt comfortable and safe the moment I walked in. They have numerous protocols in place and it feels safe and sanitary. Get your consultation at Furlong and you won't regret it!

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Jake B.
San Jose, CA

6/3/2020
Yelp

I just finished my last check up since my advanced PRK surgery.  The whole process was amazing and I now have greater than 20/20 vision. Dr. Furlong read about studies in which my eye condition would not be ideal for LASIK and recommended PRK.  I'm glad that the doctor stays on top of his research and recommends the best option to his patients. Office staff was always helpful and I highly recommend this place to anyone thinking about LASIK or PRK.

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Micaela R.
San Jose, CA

5/26/2020
Yelp

SANITARY & LIFE CHANGING!!!!! No need to wait this thing out. 

The entire staff was extremely thorough about all the necessary safety measures put in place to keep everything sanitary, and most importantly, everyone safe. It was even comforting to see them disinfecting stations right in front of me! I'm now Day 5 post-procedure and I am asking myself why I waited so long!!!!!! Both Dr. Sane and Dr. Furlong were so helpful in answering all my questions and making sure I felt comfortable throughout my entire experience!

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Danielle B.
San Jose, CA

5/5/2020
Yelp

If everything going on with Covid19 has made you consider holding off on your visit I'm here to say it shouldn't. I had my 6 month post lasik follow up today, they screen you onsite and check your temperature even before you enter the lobby. They monitor all employees as well!

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Drew E.
San Jose, CA

2/1/2020
Yelp

Dr Furlong and his team did a great job performing lasik. I hated wearing contacts and I'll hopefully never have to wear any again. I don't regret regret coming here one bit. They are highly experienced and made this procedure seem easy.

Gene F.
Milpitas, CA

12/30/2019
Yelp

I'm giving Dr. Furlong and the staff at Furlong Vision Correction five stars for restoring my blurry vision to what is now perfect vision. Prior to the surgery in October (which only took ten minutes overall - in and out and you're done,) my vision was terrible due to the formation of cataracts

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Jaibe B.
San Jose, CA

2/26/2020
Yelp

I cannot thank Furlong Vision Correction and most especially the staff and Dr. Sane for giving me the gift of vision.

The process, the anxiety, the research all led me to finally getting LASIK. First off my wife and our very good friend all got LASIK & PRK with Dr. Sane. She has done a really good job in every step of the process.

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Morgan K.
Gilroy CA

2/8/2020
Yelp

Very happy with Furlong Vision. My Boyfriend went and saw Dr. Sane and she was wonderful! She explained the Cornial Cross Linking (CXL) very well. The tech that helped us prior to seeing Dr. Sane was wonderful as well. Very polite, attentive, and very informative in everything he was doing.

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Renae M.
Santa Rosa, CA

3/19/2020
Yelp

I highly recommend getting LASIK at Furlong Vision! Dr. Furlong and his staff were all calm, professional, and helpful throughout the entire process. I got LASIK about 4 weeks ago and my vision is great and eyes are healed.

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Jerry M.
Santa Cruz, CA

11/15/2019
Yelp

Dr. Mona Sane.....a perfect 10!......she and everyone connected with my experience was a 10!.....the front desk folks, the technical staff, the equipment at the office location, the surgery facility....all were a 10! Very little pain involved and the outcome has been outstanding.....highly recommend to anyone in need...

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Ashley Y.
Mid-city, San Diego, CA

11/14/2019
Yelp

Had LASIK back in 2017 with Dr. Furlong. A family member recommended him and I would definitely go back to Furlong again if I need to. I used to have a -6 prescription but now my vision is near perfect.

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Teresa N.
Milpitas, CA

11/4/2019
Yelp

I couldn't be happier with my experience here. I put in a LOT of research before choosing to move forward with Furlong - you only get one pair of eyes, and I wanted to ensure I was leaving them in good hands. I was sold on not only their excellent reputation but their impressive, state-of-the-art technology.

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Raylina B.
Gilroy, CA

10/25/2019
Yelp

From my grandmother: Dr. Mona Sane thank you very much for the cataract surgery that you performed on my eyes. I appreciate everything you did, as well as the incomparable care you gave me. It was excellent!

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Brenda M.
San Francisco, CA

10/26/2019
Yelp

This place is amazing! Thank You so much Dr. Furlong for the great experience! I had lasik surgery yesterday due to my high astigmatism.

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Danielle B.
San Jose, CA

10/31/2019
Yelp

I had my procedure last Friday morning, I was scared and really nervous. Everyone at Furlong did a great job of comforting me. If anyone is considering having this procedure I would completely recommend it. It was so quick and the recovery has been very easy. Dr. Furlong is and his staff are nothing short of amazing.

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Akeem S.
San Jose, CA

1/31/2019
Yelp

I was incredibly nervous leading up to having the Lasik procedure done. Melody who is one of the staff members was so supportive and reassuring throughout the entire process. On surgery day she had me in tears from laughter and so I was so comfortable leading up to the procedure. The procedure went so smoothly I was...

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Brian S.
Capitola, CA

12/8/2018
Yelp

I could not recommend Dr. Furlong and team any more highly. Incredibly friendly and personal team, with effective and focused service, and the most frictionless simplest surgery I could ever imagine having. I am less than 24 hours after my surgery - and the results are incredible. I am looking for to taking my...

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Bruce F.
San Francisco, CA

2/17/2019
Yelp

Dr. Sane performed my laser cataract procedures at El Camino Surgery Center. Quick, painless and instant perfect vision!  I have never had a better medical experience!

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Lydia A.
San Jose, CA

1/28/2019
Yelp

I had Lasik done with Dr. Sane ten days ago at Furlong Vision and I am absolutely pleased. From the initial consultation to the actual procedure and after care. They have snacks and drinks in the waiting room, everyone is so kind and passionate about their work. I felt very welcome and they were great about answering...

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Mer D.
San Francisco, CA

4/8/2019
Yelp

Furlong Vision took care of me so well. Pre op, you'll have so many questions, possibly even some doubts, but the information and patient onboarding process is so smooth that you'll equipped to face anything. They aren't there to swindle you out of your hard earned dollars!! Nono. They are here on the singular mission...

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Nicole R.
Los Angeles, CA

3/25/2019
Yelp

I just had my annual eye exam - I still have 20/20 following this procedure, and my optometrist always says "your surgeon did an excellent job!" :)

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Solomon A.
San Jose, CA

3/15/2019
Yelp

We did an extensive research for my wife's Andreja important step as eye Lasik surgery is. We included Furlong Vision in that research. It was also recommended by our friend Melissa who did her Lasik with them many years ago and is still excited with the whole experience and results.

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Tu-Anh N.
San Luis Obispo, CA

3/25/2019
Yelp

My LASIK experience at Furlong Vision was beyond amazing. Everybody at the center including the technicians, assistants, Dr. Patel, Dr. Shen, and Dr. Furlong made sure I felt comfortable and confident in my decision to get refractive surgery every step of the way. My vision correction has been life changing, I can...

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Lauren S.
Downtown, Campbell, CA

3/28/2018
Yelp

Dr. Furlong and his entire staff have changed my life! After 11 years of dealing with contacts and glasses, I finally took the Lasik plunge and am SO thankful I did! Dr. Furlong and his staff were so informative, friendly, and reassuring. They made everything so easy and made me feel 100% comfortable...

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Nlramesh R.
Mount Hope KS

4/7/2018
Yelp

Amazing doctors and staff.  Dr. Mona Sane did my cataract surgery and she was absolutely awesome!! The staff at Dr. Furlong's and at the surgery center were super professional and you just knew you were going to be alright at the end of the procedure.  The post op care was just excellent !! If...

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McKinley S.
Marina, CA

2/16/2018
Yelp

I had Lasik 1 year ago and I am still amazed by how well I can see. I have worn glasses and contacts for many years.  I could see well with my contacts so I was expecting to see like that after Lasik. What I didn't expect, was how much better I see now after Lasik. The quality is SO MUCH BETTER. I...

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Kim M.
Santa Clara, CA

1/30/2018
Yelp

This review is long overdue. I actually had my surgery done about a year ago. I had been told for several years from various optometrists I would never be able to even have the surgery because of an eye condition. But when I started to see Dr. Ratra at Dr. Gold & Associates, she referred me to...

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Jennifer B.
Prescott, AZ

1/16/2018
Yelp

In October I underwent LASIK surgery with Dr. Furlong and his staff and I couldn't be happier. It has been life changing after 23 years of wearing contacts and glasses. I had a high astigmatism prescription and at my first last post op checkup about a two months post op I was at -20/20 in the left...

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Voted Best LASIK Doctor by Santa Cruz Good TimesTwice named a Premiere Cataract Surgeon by Ocular Surgery NewsSponsor of Santa Clara County Optometric SocietyJefferson Award - the "Nobel Prize" for community and public service for the Furlong Vision Correction Gift of Sight programOfficial laser vision correction and eye surgeon and Legacy Partner of the San Jose Earthquakes