Combined ab-interno trabeculectomy and cataract surgery induces comparable intraocular pressure reduction in supine and sitting positions

AIM:To analyze the therapeutic effect of combined abinterno trabeculectomy and cataract surgery on intraocular pressure(IOP)levels in supine and sitting postures during a 24-hour IOP profile.METHODS:Twenty-six eyes of twenty-six patients receiving ab-interno trabeculectomy using electroablation of the trabecular meshwork combined with cataract surgery or stand-alone were included in this retrospective analysis.IOP change during 24-hour IOP profiles within two years postoperatively were analyzed for eyes receiving surgery(“study eyes”)and compared to fellow eyes,which had not received surgery.Clinical data including mean sitting IOP(siIOP),mean supine IOP(su IOP)and the number of topical antiglaucomatous medications(TAM)were extracted from patients’files.RESULTS:Preoperatively,si IOP was 17.6±5.3 mm Hg in study and 17.1±4.7 mm Hg in fellow eyes(P=0.347).Patients were treated with an average of 2.8±1.0 TAM.Best corrected visual acuity(BCVA)was significantly worse in study eyes(P<0.001),visual field function was marginally not significantly dif ferent(P=0.057).Af ter surger y 9.6±6.8 mo,study eyes had a mean si IOP of 14.5±3.6 mm Hg(IOP reduction:-3.2 mm Hg,P=0.009),a mean su IOP of 18.0±3.5 mm Hg,and an average of 1.3±1.34 TAM(P<0.001),while in fellow eyes,mean si IOP was 16.2±3.4 mm Hg and mean su IOP was 20.5±5.1 mm Hg.Postoperatively,the relative IOP increase between sitting and supine postures was approximately 30%in both study and fellow eyes(P=0.99).CONCLUSION:IOP after ab-interno trabeculectomy shows a comparable relative reduction in both supine and sitting position.Classical trabeculectomy is known to lower su IOP overproportionally.