Visual and tear function improvement after superficial phototherapeutic keratectomy (PTK) for mid-stromal corneal scarring

Purpose To study the changes in visual and tear film function following sup erficial excimer laser phototherapeutic keratectomy in patients with mid-st romal corneal scars. Methods Fourteen eyes of 14 patients with mid-stromal conceal scars seen at the Department of Ophthalmology at Kobe Kaisei Hospital underwent superfic ial phototherapeutic keratectomy (PTK). The subjects underwent routine opht halmic examinations, corneal sensitivity measurements, tear film break-up t ime (BUT), Schirmer test and tear film lipid layer interferometry. Thirty e yes of 15 normal control subjects were also studied. The patients and the c ontrol subjects were compared for pre-PTK tear function parameters and tear film lipid layer interferometry grade. The alterations in these parameters within 6 months following PTK were also determined. Results Visual improvement was achieved in 12 eyes (86%). A hyperopic shift was observed in all eyes. The average pre-PTK corneal sensitivity and tear film BUT were lower in patients compared with control subjects before PTK. Tear film lipid layer interferometry grades were also higher in the patien ts than the controls before PTK. All these parameters improved gradually an d significantly after PTK. Schirmer test results did not show any significa nt alterations after PTK. Conclusion We conclude that PTK is an effective means of treating corneal s cars and attaining visual improvement, even in cases with deeper corneal in volvement and may obviate the need for corneal transplantation. Simultaneou s improvements in conceal sensitivity and tear film stability suggest favou rable effects of PTK on the ocular surface.