Refractive outcome after pars plana vitrectomy for macular hole in pseudophakic eyes

Full-thickness macular hole (FTMH) is routinely treated with pars plana vitrectomy (PPV), internal limiting membrane (ILM) peeling and intravitreal gas fill with good visual acuity (VA) outcome (Christensen et al. 2009). It is important that PPV does not cause major refractive change (RC), especially in pseudophakic eyes that achieved emmetropia after cataract surgery (Hamoudi et al. 2013). The aim of this study was to evaluate the RC in pseudophakic eyes undergoing PPV with ILM peeling and gas tamponade. We retrospectively reviewed the charts of 44 eyes undergoing surgery for FTMH with uncomplicated PPV, ILM peeling and intravitreal tamponade with perflouropropane (C3F8) at our institution. Pseudophakic eyes were included if preoperative refraction was less than ±5 dioptres (D) and astigmatism <3 D and had an in-the-bag intraocular lens (IOL). Eyes were excluded in case of intraoperative IOL manipulation, postoperative synechiae or surgical complications (retinal detachment, endophthalmitis or vitreous haemorrhage). The refraction was measured 1 day before PPV and repeated after 3 months. Measurement was with an autorefractor (Retinomax, Nikon, Japan) and was confirmed by manual refraction. All refractions are expressed as spherical equivalents. The average age was 69 years, and 70% were women. The FTMH was closed in all the eyes. None of the fellow eyes had intraocular surgery during the follow-up time. The refraction was −0.69 ± 1.04 D (median ± standard deviation) before surgery, and −0.50 ± 0.93 D after surgery. The median RC of +0.25 ± 0.80 D was not significant (p = 0.36). The RC was towards myopia in 32% and towards hyperopia in 55%, while 13% had no RC. The postoperative RC was within ±0.25 D, ±0.50 D and ±1.00 D in 30%, 48% and 84% of the eyes, respectively, see Fig. 1. The numeric median RC was 0.63 ± 0.47 D. The fellow eyes had no RC. In this retrospective study, we found a small RC towards hyperopia in a homogenous group of pseudophakic eyes undergoing PPV for FTMH. Following vitrectomy, phakic eyes commonly develop cataract that may cause myopia. We eliminated cataract as a confounder by only including pseudophakic eyes. Previous studies of PPV in pseudophakic eyes have mainly reported a myopic RC (Hamoudi & La Cour 2013), and only few have reported hyperopic RC (Emanuelli et al. 2012). Although small-gauge PPV has reduced the surgically induced astigmatism and made the optical rehabilitation faster, the refractive outcome is similar after few months (Avitabile et al. 2010). Several explanations exist for the observed RC after PPV, including changes in the axial length, anterior chamber depth, keratometry, macula thickness, amount of tamponade and the index of refraction (which is not identical for the vitreous body and the aqueous). It is a weakness in the retrospective nature of this study that we have no records on these parameters. In conclusion, we found a small non-significant hyperopic shift of +0.25 D, and 52% had a change of ±0.50 D or more.