Cutting Edge Glaucoma - Issue 2

TWO-YEAR RESULTS OF A MULTICENTER STUDY OF THE AB INTERNO GELATIN IMPLANT IN MEDICALLY... • 37  Fig. 6: Number and percentage of eyes achieving specified IOP levels in the overall mITT population ( a ) and implant alone vs. phaco + implant groups ( b ). IOP , intraocular pressure; mITT , modified intent-to-treat; phaco , phacoemulsification with intraocular lens replacement; SD , standard deviation those who underwent cataract surgery alone (mean IOP: 17.9 [3.0] mmHg at baseline, 17.8 [3.3] mmHg at 24 months) [ 30 ]. Similarly, the mean number of IOP-lowering medications used at 24 months was not statistically significantly different between treatment groups [ 30 ], suggesting limited long-term effectiveness of the device. We did not expect to see additional IOP lowering in the phaco + implant group, because many studies looking at trabeculectomy and phaco-trabeculectomy have shown comparable IOP lowering with both procedures [ 31 – 38 ]. Both phacoemulsification and trabeculectomy tech- niques have evolved, which might explain why more recent papers report no differences in outcomes between trabeculectomy alone vs combined with phacoemulsification. The gelatin stent relies on a similar outflow pathway as trabeculectomy [ 39 – 41 ], but is a much less invasive procedure and provides a more controlled outflow; these factors likely explain the lack of differences between the two groups ob- served in our study. How the effectiveness of the trabecular micro-bypass stent compares with that of the gelatin implant remains to be deter- mined because the primary and secondary outcomes in studies of the trabecular micro-bypass stent assessed IOP lowering from unmedicated/washed-out baseline [ 10 , 30 ]. In our study, eyes did not undergo washout before surgery, so the baseline IOP was expectedly lower. Also, most patients included in this study had moderate POAG, with an average visual field mean deviation of − 8.0 dB, compared with − 3.9 dB in the trabec- ular micro-bypass study [ 10 , 30 ]. ≤ 18 mmHg ≤ 15 mmHg ≤ 12 mmHg 83.7 85.1 60.7 62.7 27.5 24.2 0 10 20 30 40 50 60 70 80 90 100 42htnoM 21htnoM Eyes (%) achieving specified IOP levels n = N = 149 178 108 178 49 178 137 161 101 161 39 161 Mean IOP (SD), mmHg 13.5 (2.7) 12.3 (2.2) 10.4 (1.7) 13.8 (2.4) 12.8 (1.8) 10.8 (1.0) 80.4 87.7 59.8 61.7 27.8 27.2 0 10 20 30 40 50 60 70 80 90 100 Implant alone Phaco + implant Eyes (%) achieving specified IOP levels n = N = 78 97 58 97 27 97 71 81 50 81 22 81 Mean IOP (SD), mmHg 13.4 (2.9) 12.2 (2.3) 10.2 (1.9) 13.6 (2.5) 12.5 (2.0) 10.6 (1.5) 82.6 88.0 59.3 66.7 26.7 21.3 0 Implant alone Phaco + implant 71 86 51 86 23 86 66 75 50 75 16 75 13.8 (2.5) 12.6 (1.9) 10.8 (1.0) 13.9 (2.3) 12.9 (1.6) 10.9 (1.1) 42htnoM 21htnoM a b Fig. 6 Number and percentage of eyes achieving specified IOP levels in the overall mITT population ( a ) and implant alone vs. phaco + implant groups ( b ). IOP, intraocular pressure; mITT, modified intent-to-treat; phaco, phacoemulsification with intraocular lens replacement; SD, standard deviation 992 Graefes Arch Clin Exp Ophthalmol (2019) 257:983 – 996 Table 3: Mea IOP at months 12 and 24 in eyes that were IOP-lowering medication-free (mITT population). Visit Mean IOP, mmHg (SD) Implant alone N = 114 Phaco + implant N = 88 Total N = 202 Month 12 13.8 (3.4) 13.7 (2.7) 13.8 (3.1) Baseline IOP 21.9 (3.5) 20.6 (3.5) 21.3 (3.5) n (%) a 50/97 (51.5) 41/81 (50.6) 91/178 (51.1) Month 24 14.4 (3.4) 14.3 (2.7) 14.3 (3.1) Baseline IOP 22.1 (4.0) 20.6 (3.6) 21.4 (3.9) n (%) a 39/86 (45.3) 33/75 (44.0) 72/161 (44.7) IOP , intraocular pressure; mITT , modified intent-to-treat; phaco , phacoemulsificationwith intraocular lens placement; SD , standard deviation a Based on the number of eyes with data available at baseline and the indicated visit