1. Evaluation of Post-Trabeculectomy Visual Function Using Orbscan Kozue Kasai MD 1 Tadashi Nakano MD 1 Takahiko Noro MD 1 Hideki Matsuda MD 1 Yoshinori Itou MD 1 Masayuki Tatemichi MD 2 Hiroshi Tsuneoka MD 1 1 The Jikei University School of Medicine Department of Ophthalmology 2 Showa University

2. Purpose 1. To evaluate changes in corneal topographic characteristics of patients after trabeculectomy (LEC). 2. To study the relationship of central corneal thickness using Orbscan.

3. Methods and Patients Post-trabeculectomy group with OAG24 eyes Control group16 eyes (nonoperated eyes of post-LEC patients or volunteer eyes) TOTAL40 eyes (24 patients were examined with Orbscan at our glaucoma outpatient clinic)

4. Post-LEC group 20 patients 24 eyes Control group 13 patients 16 eyes p value** Age (years) 58.8±15.267.3±5.60.580 Sex (man / woman) 11 / 98 / 50.508 Visual acuity (log) 0.60±0.581.00±0.170.001 Spherical equivalent [D]*-3.72±3.45-1.14±3.500.001 Corneal astigmatism [D]*-1.59±0.96-0.80±0.500.004 Tonometry [mmHg]11.4±4.7216.3±5.640.009 Corneal thickness [  m] 556±38.6558±43.70.978 Postoperative period [months]48.1±51.3 * NIDEK ARK-700A** Mann-Whitney U-test Methods

5. ORBSCAN ver 3.0 Evaluation items Using an illuminated ring pattern and a beam of light, Orbscan shows surface power and the front and back shapes. Not effected by eye dryness. Time: less than 2 seconds Using two groups (3-mm and 5-mm zone irregularity [ZI]) * Mean power: The average of the maximum and the minimum of the cornea refractivity in the arbitrary measurement point ** astigmatic power: The difference of the maximum and the minimum of the cornea refractivity in the arbitrary measurement point (Standard deviation of Mean power*) 2 + (Standard deviation of astigmatic power**) 2 √ Irregularity =

6. Methods 5-3-mm ZI Difference between 5-mm ZI and 3-mm ZI (5-3-mm ZI) as an index of the peripheral area Corneal thickness was measured by Orbscan slit scan pachymetry. A representation of the central corneal thickness. (within a 3-mm circle from the center) 1. Zone Irregularity 3-mm ZI Central corneal Irregularity miosis (daytime condition) 5-mm ZI Corneal irregularity of paracentral quadrants mydriasis (night condition) 2. Corneal thickness

7. 0 1 2 3 4 5 6 7 Results 1 Irregularity vs treatment * 3-mm Zone5-mm Zone 5 ‐ 3-mm Zone Irregularity was greater in the Post-LEC group than in the control group in all zones. Post-LEC Control Irregularity Mann-Whitney U-test * * * P < 0.5 ** P < 0.01 *** P < 0.001

8. Results 2 Irregularity vs Corneal thickness Irregularity was greater with corneal thickness < 540  m than with corneal thickness ≧ 540  m in the zones. Mann-Whitney U-test 0 2 4 6 8 10 12 3-mm Zone5-mm Zone 5 ‐ 3-mm Zone Irregularity <540  m ≧ 540  m ** * * P < 0.5 ** P < 0.01 *** P < 0.001

9. Report of Evaluation of Post-trabeculectomy 1. Video-keratoscopy After LEC, the peripheral parts of the cornea near the scleral flap area become steep. After LEC, visual acuity decreased with topographic changes near the scleral flap. 2. TMS-1 TMS-2 Video-keratoscopy After LEC, there are no changes in SRI or SAI as indexes of astigmatic irregularity. 3. TMS-1 After LEC, The steep area around the cornea does not influence the corneal center. 4. OPD-scan After LEC, surgically induced astigmatism and higher-order aberrations increase significantly. Contrast sensitivity is decreased. Back Ground 1. The importance of quality of vision (QOV) is widely recognized. 2. Towards the Standaridization of QOV (Quality of vision),the list of clinical useful parameters need to be evaluated. 3. Corneal astigmatism is a factor in QOV. It can’t be predicted before surgery. 4. The irregularity astigmatism is important, but postoperative QOV deteriorates because of the regular astigmatism.

10. Conclusion 1 1. Irregularity was significantly greater in the post-LEC group. ZI may serve as a new index of postoperative quality of vision. 2. Irregularity was significantly greater when corneal thickness was less than 540  m. Central cornea thickness may be a useful predictor of surgically induced astigmatism.

11. Conclusion 2 1. Orbscan is an effective method for evaluating visual function after trabeculectomy. 2. The results of this study suggest that corneal thickness may have a significant effect on changes in corneal shape after glaucoma surgery.

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