20G and 25G Macular Surgery: Anatomic and Functional Results

Abstract

Purpose: : To evaluate safety and effect of 20 Gauge or 25 Gauge vitrectomy with macular peeling and Inner Limiting Membrane (ILM) removal in vitreo-retinal interface syndromes.

Methods: : Prospective, single-center, non comparative study conducted in Vitreo-Retinal Unit of University Eye Clinic of Policlinico S. Matteo.We selected 40 eyes of 39 patients (16 male, 23 female) that underwent 20G or 25G macular surgery performed by single surgeon (VG) for one of these diseases: Idiopathic Full Thickness Macular Hole (FTMH), Macular Pucker (MP), Tractional Diabetic Macular Oedema (TDMO) or Vitreomacular Traction Syndrome (VMTS). Mean patients age was 73,82 years. 1 pre-operative evaluation was conducted, followed by 3 post-operative ones: at 7 days, 35-40 days and 4-5 months.We evaluated anatomic outcomes with biomicroscopy and optical coherence tomography (OCT), while visual function were estimated with Snellen type visual acuity (VA) test. In pre-operative evaluation we took in consideration age and sex, Visual Acuity (VA), lens condition and IOL (intra ocular lens) presence, inteface disease type and OCT exam.In follow-up we performed evaluation of VA, lens conditon and IOL presence, OCT, biomicroscopy evaluation of eventual post-surgery complications.

Results: : We had VA improvement in 67% of patients with 1,7 Snellen Lines (SL) mean improvement. Unmodified VA in 25% of patients, whose 3 developed lens opacity. 8% came out with a mean VA reduction of 0,9 SL, every one of them developing lens opacity after pre-operative visit. Among different diseases we didn’t assessed any substantial difference in VA improvement: 2,2 SL in MP, 2 SL in VMTS, 1,1 SL in TDMO, 0,8 SL in FTMH. VA variations resulted statistically significant at Student t-test (p<0,05).In every MP, VMTS and TDMO case a foveal thickness and macular volume decrease were observed with OCT. Mean thickness reduction was 137 µm: 130 µm in MP, 186µm in VMTS, 91 µm in TDMO. Mean volume reduction was 1,58 mm³: 1,27 mm³ in MP, 2,21 mm³ in VMTS, 2,15 mm³ in TDMO.Difference between foveal thickness and macular volume values pre- and post-operative is statistically significant with Student t-test (p<0,05).In FTMH a macular profile restoration after surgery was highlighted with OCT in 64% of patients: these ones had a mean lesion size (basis measured) of 683 µm before surgery. Only one patient encountered Retinal Detachment.

Keywords: macula/fovea • vitreoretinal surgery • retina