I saw a patient from Oxnard today in my Ventura office who asked me about dry after PRK and LASIK. In ophthalmology, we have a term called “the ocular surface” which refers to the environment on the front surface of the eye. When we talk about “the ocular surface”, we’re generally talking about eye surface issues such as dryness, inflammation, and tear quality. A study was recently published in the Journal of Cataract and Refractive Surgery which compared contemporary PRK to contemporary LASIK. 44 eyes of 22 patients were separated into either a PRK group or a LASIK group. The LASIK patients had their flaps created with the Intralase iFS femtosecond laser. The LASIK flaps were set at 100 micron depth (“SBK flap“) with a superior hinge. The ocular surface was measured at 3, 6, and 12 months after surgery. Tests included a patient dry eye questionnaire, tear osmolarity, corneal sensation, signs of corneal dry eye using fluorescein staining, tear break up time, and Schirmer 1 testing of tear production.  Both PRK and LASIK patients scored well in all this testing. Both procedures, however, produced reduced corneal sensation at the 3 month mark, although it was worse with LASIK than with PRK. Decreased corneal sensation is associated with dry eye since good corneal sensation tells the eye when to unconsciously blink and tear to compensate for dryness. By 12 months, however, corneal sensation returned to the pre-operative baseline in both groups. In fact, all parameters were back to normal levels by 12 months. The authors concluded,  “the ocular surface condition could be considered clinically unaltered after 1 year in both groups.” These studies confirm what I typically have seen in my own practice over the past 20 years of performing both PRK and LASIK.