To determine the minimum depth of phototherapeutic keratectomy (PTK) required for diffuse haze removal in granular corneal dystrophy type 2 and to determine whether Fourier domain optical coherence tomography (FD-OCT) can be an effective technique for predicting the exact required depth of ablation.
The depth of ablation used for diffuse stromal haze removal was evaluated with the slit lamp and serially taken photographs during the PTK procedure. The depth of diffuse haze was measured preoperatively using FD-OCT.
Forty-three eyes of 30 patients were included in this study. The mean age of the patients was 62.0 ± 8.4 years. The mean depth of PTK required was 43.7 ± 6.2 μm (range, 31–59 μm). The mean follow-up period for 29 eyes of 22 patients, who had follow-up periods of more than 6 months, was 21.0 ± 12.0 months. The mean best spectacle-corrected visual acuity of these 29 eyes was 0.43 ± 0.15 preoperatively and 0.71 ± 0.16 (P = 0.022) 1 month postoperatively. Of the 43 eyes of 30 patients, FD-OCT was evaluated in 29 eyes of 22 patients. The mean preoperative depth of diffuse haze using FD-OCT was 44.3 ± 6.4 μm. The mean depth of ablation required to remove diffuse stromal haze was 44.5 ± 5.9 μm. The actual ablated depths correlated well with the depth of haze detected by FD-OCT preoperatively (intraclass correlation coefficient = 0.719).
FD-OCT is an accurate method of predicting the depth of PTK required to remove visually significant diffuse haze in patients with granular corneal dystrophy type 2. We advocate the use of slit-lamp biomicroscopy after the initial 30-μm ablation to determine the necessity for any further ablation.
*Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, Korea
†Stulting Research Center, Woolfson Eye Institute, Atlanta, GA
‡Brain Korea 21 Project for Medical Science, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea.
Reprints: Eung Kweon Kim, Department of Ophthalmology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Korea (e-mail: firstname.lastname@example.org).
Supported by a National Research Foundation of Korea grant funded by the Korea government (No. 2011-0028699).
The authors state that they have no conflicts of interest to disclose.
Received October 18, 2011
Accepted January 8, 2012