1. Visual and IOP Outcomes after PRK in Pigment Dispersion Syndrome [Poster Number: P190] Kraig S. Bower, Denise A. Sediq, Charles D. Coe, Keith Wroblewski, Chrystyna P. Kuzmowych, Jennifer Eaddy, Rose Kristine C. Sia Center for Refractive Surgery, Walter Reed Army Medical Center, Washington, DC The authors do not have any financial interests or relationships to disclose. Disclaimer: The views expressed in this poster are those of the authors and do not reflect the official policy of the Department of the Army, Department of Defense, or the U.S. Government.

2. Introduction: Pigment dispersion syndrome (PDS) is present in approximately 4% of the population, and is more common in patients with myopia. One study has reported the safety and efficacy of LASIK in patients with PDS [Jabbur et al]. To date, we have found no published study that evaluates the safety and efficacy of PRK in patients with PDS. Purpose: The purpose of this study is to analyze visual outcomes and intraocular pressure following PRK in patients with PDS to determine the safety and efficacy of PRK in patients with PDS.

3. Methods We retrospectively reviewed the records of refractive surgery patients with clinical findings of PDS who underwent PRK at the WRAMC Center for Refractive Surgery between January 2002 and July 2008. Records were reviewed for gender, age, ablation depth (AD), surgical complications, manifest spherical equivalent (MSE), uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), intraocular pressure (IOP), central corneal thickness (CCT), cup-to-disc (C/D) ratio, and postoperative complications, including steroid response glaucoma.

4. Methods continued All data were analyzed using SPSS, version 15.0 (SPSS Inc., Chicago, IL). Repeated measures analysis of variance (RM- ANOVA) was used to examine IOP and corrected (Rosa, Kolhaas, and Svedburg) measurements over time (significance testing used an alpha=0.05). A Wilcoxon signed ranks test was used to compare pre and post operative C/D ratio. Data are presented as the mean ± standard deviation (SD), unless otherwise indicated. In addition to analyzing the GAT measured postoperative IOP, we also analyzed corrected IOP measurements. [Rosa et al., Kolhaas et al., Svedburg et al.].

5. Results 29 eyes of 15 soldiers (14 males and 1 female) mean age 37.7±7.0 years (range 24 to 49 years) with at least 12 months follow-up were included for the review. Mean pre-operative MSE was -3.69±2.22D (range -1.13 to -8.25D). Mean AD was 55.4±27.1μ (range 17.3 to 113.6μ). Mean CCT pre-operatively was 567.6±23.9μ (range 513 to 608). Mean postoperative CCT was 505.6±40.4μ (range 444 to 571). Patient data is presented in Table 1.

6. Table 1. Patient demographics and intraocular pressure (IOP) after PRK in patients with pigment dispersion syndrome. PATIENTSEXAGEF/U (DAYS)EYEMSE*AD**PRE IOP1 MO IOP3 MO IOP6 MO IOP12 MO IOPFINAL IOPPRE C/D***FINAL C/DSTEROID RESONDER? PATIENT 1M40365 OD-1.3832.41815161519 0.40 NO OS-1.5027.71716 1819 0.40 NO PATIENT 2M49351 OD-3.2544.41617141016 0.600.70NO OS-3.8858.81413101412 0.550.65NO PATIENT 3M43365 OD-1.8830.22728232522 0.30 YES OS-2.6339.62324182122 0.30 YES PATIENT 4M38962 OD-1.2517.31514 12N/A120.250.30NO OS----- PATIENT 5F38373 OD-7.63113.61817101812 0.300.25NO OS-7.50104.6181491812 0.300.25NO PATIENT 6M32367 OD-4.5066.31813121115 0.20 NO OS-4.7567.721 131415 0.300.20NO PATIENT 7M37679 OD-1.2526.71710N/A12N/A120.350.40NO OS-1.2519.31810N/A13N/A130.350.40NO PATIENT 8M25405 OD-3.2552.616141210880.200.35NO OS-3.6356.317141310880.200.35NO PATIENT 9M41371 OD-3.6352.71314201315 0.350.25NO OS-3.8856.21415181416 0.350.25NO PATIENT 10M36420 OD-3.1352.62432131519 0.40 YES OS-2.7552.72328141517 0.40 YES PATIENT 11M45367 OD-1.1330.6161716 19 0.30 NO OS-2.0045.41517 1619 0.30 NO PATIENT 12M41358 OD-3.8856.21415121516 0.30 NO OS-3.8856.31415121618 0.30 NO PATIENT 13M24356 OD-1.8830.621151819 0.20 NO OS-1.7530.72216182220 0.250.20NO PATIENT 14M32365 OD-7.5094.51011171211 0.30 NO OS-6.7591.01210171213 0.30 NO PATIENT 15M44349 OD-8.25101.11610141611 0.300.20NO OS-7.0097.81510121610 0.30 NO

7. Results Post-op 89.7% of eyes were within 0.5D and 100% within 1.00D of emmetropia. BSCVA was unchanged from pre-op in 82.8% of eyes, while 17.2% of eyes gained one line BSCVA. No eye lost greater than one line BSCVA from any cause. Three of 15 patients (20%), including the patient with pre- existing ocular hypertension, were steroid responders. All 3 were managed with addition of a single topical agent which was discontinued after completing steroids. There was no significant change in mean C/D ratio from baseline (0.322+/-0.091) to final visit (0.328+/-0.118, p=0.73).

8. UCVA follow-up with mean final FU 413 days post-op (range 349 to 962 days)

9. IOP, Svedburg corrected IOP, Kolhaas corrected IOP, and Rosa corrected IOP over time in postoperative PRK patients with PDS. (Error bars are standard error of the mean). *Significantly different over time. P=0.20

10. Conclusions Our refractive outcomes were similar to those reported by other investigators and equivalent to our experience with surface ablations in patients without PDS. While post-op steroid response was common, PRK is safe and effective in patients with PDS if IOP is carefully monitored postoperatively.

11. References 1.Jabbur NS, et. al. Outcomes of laser in situ keratomileusis in patients with pigment dispersion syndrome. J Cataract Refract Surg 2004;30(1):110. 2.Rosa N et al. Goldmann applanation tonometry after myopic photorefractive keratectomy. Acta Ophthalmol Scand 1998;76(5):550. 3.Kolhaas M et al. A Correction Formula for the Real Intraocular Pressure after LASIK for the Correction of Myopic Astigmatism. J Refract Surg 2006;22:263-267. 4.Svedburg H et al. Changes in corneal thickness and curvature after different excimer laser photorefractive procedures and their impact on intraocular pressure measurements.