LASIK and CK patients pleased with monovision, study finds

August 12, 2009

Presbyopia — the normal age-related loss of reading vision — can be particularly troubling to refractive surgery patients who want freedom from eyeglasses after surgery.

One way to reduce dependence on reading glasses after vision correction surgery is to undergo a monovision correction, where one eye is corrected for distance vision and the other is corrected for near vision.

Monovision can be created with most types of vision correction surgery, including LASIK and conductive keratoplasty (CK).

Recently, researchers in the UK evaluated patient satisfaction with monovision refractive surgery and found most patients are pleased or very pleased with the results.

Monovision LASIK and CK study: Design and methods

The researchers evaluated patient satisfaction with visual outcomes in 287 consecutive refractive surgery patients who opted for a monovision correction with either LASIK or CK.

Patients were divided into four groups, based on the type of treatment they received:

Group One consisted of 36 patients with low myopia who received a monovision correction by having only their dominant eye corrected with LASIK for distance vision. No treatment was applied to the other eye, leaving it mildly nearsighted.
Group Two consisted of 97 patients with moderate to high myopia who received bilateral LASIK treatment for monovision, with the target of leaving the non-dominant eye mildly nearsighted.
Group Three consisted of 106 patients with good uncorrected distance vision who were given monovision by having a near vision CK correction applied to their non-dominant eye.
Group Four consisted of 48 farsighted patients who were given monovision by having both eyes treated with LASIK, with the target of producing low myopia in the non-dominant eye.

Four weeks after surgery, patients were asked to complete a questionnaire that assessed their satisfaction with their surgical monovision correction.

The patients were asked to grade their satisfaction with their vision using one of five scores: 1) Couldn't be better; 2) Pleased with result; 3) Satisfactory outcome; 4) Had hoped for better; 5) Regret having had it.

Monovision LASIK and CK study: Results

Monovision was found to be well-accepted by all treatment groups. The breakdown of scores in each group are as follows:

Group One (unilateral LASIK - mild myopia)

44.4 percent - Couldn't be better
44.4 percent - Pleased with result
8.3 percent - Satisfactory outcome
2.8 percent - Had hoped for better
0.0 percent - Regret having had it

Group Two (bilateral LASIK - mild to moderate myopia)

45.4 percent - Couldn't be better
35.1 percent - Pleased with result
6.2 percent - Satisfactory outcome
10.3 percent - Had hoped for better
3.1 percent - Regret having had it

Group Three (unilateral CK - good uncorrected distance vision)

36.8 percent - Couldn't be better
39.6 percent - Pleased with result
9.4 percent - Satisfactory outcome
12.3 percent - Had hoped for better
1.9 percent - Regret having had it

Group Four (bilateral LASIK - hyperopia)

25.0 percent - Couldn't be better
37.5 percent - Pleased with result
16.7 percent - Satisfactory outcome
16.7 percent - Had hoped for better
4.2 percent - Regret having had it

Monovision LASIK and CK study: Conclusions

The researchers concluded that people with low myopia who undergo unilateral LASIK to improve their distance vision in their dominant eye had the highest degree of satisfaction with monovision, with 97.1 percent reporting "couldn't be better," "pleased with result" or "satisfactory outcome."

The least satisfied monovision patients were those who were farsighted prior to surgery and received bilateral LASIK with an intentional over-correction of their non-dominant eye to make that eye mildly nearsighted. Still, 79.2 percent of these patients reported a "satisfactory outcome" or better.

The researchers said that a perfect refractive outcome is very important in monovision surgery and that even a minor deviation from the intended target can be a source of patient dissatisfaction.

They also said that proper patient selection and careful pre-operative consultation to make patients fully aware of the limitations of monovision are needed to maximize overall patient satisfaction with the procedure.