Refractive Changes Following Vitrectomy

We aimed o compare the refractive changes associated with pars plana vitrectomy with or without intraocular gas tamponade in pseudophakic eyes. This retrospective study included pseudophakic patients with Nd:YAG laser posterior capsulotomy who underwent 23G PPV between February 2015 and March 2019. Group 1 consisted of patients with regmatogenous RD who underwent PPV and 12% perflouropropane (C3F8) gas tamponade whereas Group 2 consisted of patients who underwent PPV for epiretinal membrane or vitreous hemorrhage (VH). No tamponade was used in Group 2. Minimum follow-up was 12 months.

This research was reviewed by an independent ethical review board and conforms with the principles and applicable guidelines for the protection of human subjects in biomedical research. This was a retrospective, comparative case series including pseudophakic patients who underwent PPV. Group 1 consisted of patients with pseudophakic RRD who underwent PPV and 12% perflouropropane (C3F8) gas tamponade whereas Group 2 consisted of patients with ERM or VH who underwent PPV without any tamponade between February 2015 and March 2019 at Bursa Retina Eye Hospital. Informed consent was obtained from all the participants. The study was in line with the ethical standarts of the Helsinki Declaration

Patient eligibility Patients who underwent uncomplicated cataract surgery with phacoemulsification and in-the-bag IOL implantation and subsequent neodymium:yttrium-aluminum-garnet (Nd:YAG) laser due to capsular opacification were included. Preoperative refractive data obtained after Nd:YAG laser and six months prior to vitrectomy surgery. Postoperative refractive data was obtained at 12 months after vitrectomy. Eyes with a preoperative spherical refractive error \> ±6 D or cylindrical refractive error \> ±3 D were excluded. Also eyes with corneal disorders were excluded.

Ocular parameters

All patients underwent complete ophtalmic examination including best corrected visual acuity (BCVA) in the logMAR scale, slit-lamp examination, intraocular pressure (IOP) assessment, fundus examination and autokeratorefractometry (auto kerato-refractometer KR-8800 from Topcon, Tokyo, Japan) at preoperative and postoperative month-12. Induced astigmatism values were calculated through vector analysis.

Surgical procedures

All surgeries were performed by the same surgeon (S.Y.). Retrobulbar block anesthesia (a mixture of 2 ml of lidocaine hydrochloride 2% and 2 ml of bupivacaine hydrochloride 0.5%) was used. Three port 23-gauge (G) transconjunctival PPV was performed using the vitrectomy system DORC (Dutch Ophthalmic Research Center, Zuidland, Netherlands) and Zeiss microscope with EIBOS 2 (Haag Streit, Mason, OH, USA) attachment for non-contact fundus viewing.

In group 1, all patients underwent a near-complete vitrectomy including base shaving, laser endo-photocoagulation and C3F8 gas tamponade. In group 2, patients with ERM received a limited vitrectomy including; core vitrectomy, induction of a posterior vitreous detachment if not present and peeling of the ERM and inner limiting membrane (ILM). Peripheral retina was examined with indentation to identify any retinal breaks. Neither laser endo-photocoagulation, nor gas tamponade and vitreous base shaving was performed. For patients with VH patients, a near-complete vitrectomy, including base shaving, laser endo-photocoagulation was performed except for gas tamponade. In both groups, the sclera is sutured with 8-0 polyglactin suture (Vicryl) in case of wound leakage.

Eligibility Criteria:
Inclusion Criteria

* Patients aged ≥ 18 years
* Pseudophakic patients who underwent pars plana vitrectomy

Exclusion Criteria

* Patients aged 18 years \>
* Patients with a spherical refractive error \> ±6 D
* Patients with a cylindrical refractive error \> ±3 D