Dry eye is a common symptom during the first few months after LASIK and PRK. A new study shows similar levels of dry eye after LASIK and PRK. Dry eye symptoms tend to resolve after both forms of laser eye surgery.

A patient from Thousand Oaks recently asked me about dry eye after LASIK. Dry eye after LASIK or PRK happens because the nerves at the surface of the cornea need to grow back after surgery which takes six months typically. During this time, the eye actually is less sensitive and therefore automatically blinks and tears less often in response to dryness. This makes the eye “run dry” until the nerves grow back. Traditionally, it has been thought that LASIK makes the eye more dry after surgery than PRK since LASIK interrupts more nerves. Recently, however, the trend in LASIK surgery has been towards thinner and thinner flaps, which results in less disruption of these corneal nerves.

A new study from Stanford University compared dryness after wavefront LASIK to wavefront PRK. Specifically, this randomized prospective clinical trial looked at self reported symptoms of dry eye, visual fluctuations, and foreign body sensation (the feeling that there is something in the eye). Sixty eight eyes of thirty four patients were studied. Visual fluctuations are a common symptom of dry eye, as is foreign body sensation, so all three of these parameters measured in the Stanford study are different ways patients can experience or describe dry eyes.

This study was a contralateral eye study, which is a particularly outstanding scientific method for studying eye surgery. In contralateral eye studies, one eye of a patient receives one treatment, in this case wavefront LASIK, while the other eye of the same patient receives the treatment being compared, in this case wavefront PRK. In this way, genetic variations are controlled for as both eyes are of the same patient. Similarly, since this was a study of self-reported dry eye and related symptoms, subjectivity was kept to a minimum since the same patient reported on dry eye after each of the two procedures.

The Stanford researchers found that both the LASIK and PRK group of eyes showed increases in dry eye, visual fluctuations, and foreign body sensation after surgery. By twelve months after surgery, however, there was no increase in dry eye symptoms over the baseline before surgery in either group.

Given PRK’s longer recovery time than LASIK, it was not surprising that that the PRK group had higher levels of visual fluctuation than the LASIK eyes at the one month mark, but the PRK group later caught up with the LASIK group.

For both LASIK and PRK eyes, dry eye self-reported symptoms increased significantly from pre-operative levels at the one month. By three months, however, dry eye severity scores had returned to pre-operative levels in both the LASIK and PRK groups. Visual fluctuation scores, by comparison, increased significantly for both groups at the one, three, and six month marks, but returned to pre-operative baseline by twelve months in both groups. In terms of foreign body sensation (a typical dry eye symptom and does not necessarily mean something actually is in the eye), this symptom was noted in both groups at one month, but returned to pre-operative levels after that.

This study is very reassuring in that it confirms that dry eye symptoms after both LASIK and PRK typically are temporary — not permanent. In this study, dry eye symptoms had resolved by three months and visual fluctuations, a more subtle dry eye related problem, persisted until twelve months, after both LASIK and PRK. It is also interesting to see that, except for more visual fluctuations at one month in the PRK group, both the LASIK eyes and PRK eyes followed a very similar post-operative pattern suggesting there is not a significant benefit, at least in this study, to having PRK instead of LASIK in terms of post-operative dry eye.

See Also

Prospective, Randomized Comparison of Self-reported Postoperative Dry Eye and Visual Fluctuations in LASIK and Photorefractive Keratectomy
Dry eye symptoms after wavefront LASIK and PRK were evaluated in this prospective, randomized clinical trial from Stanford University.

Dry Eye, Visual Fluctuations, Foreign Body Sensation Increase Early After LASIK, PRK
Dry eye symptoms increase early after LASIK and PRK laser eye surgery, but ultimately return to pre-operative baseline in this study.

Dry Eye and LASIK
All About Vision discussion of dry eye after LASIK.

Autologous Serum Eye Drops for Dry Eye After LASIK
A paper from Japan looking at various treatment options for dry eye after LASIK.

Dry Eye Risk Similar After Laser Vision Surgeries
Reuters News article about dry eye symptoms after LASIK and PRK.

Not All Post-Op Dry Eye is Dry Eye
An EyeWorld ophthalmology journal looking at causes of dry eye symptoms after LASIK laser vision correction.