Study Design
This prospective study was approved by the institutional Review Board (approval no. YKH_26_05_12) and adhered to the tenets of the Declaration of Helsinki. The study procedures followed all institutional guidelines, and all patients provided informed consent. Patients requiring PKP combined with PPV and IOL-sutures from July 2014 to March 2017 were enrolled.
Surgical Technique
All surgeries were performed under general anaesthesia. All of the surgical steps are shown in Figure 1. The surgical design was determined prior to the surgical steps. Firstly, two scleral tunnels were created after resecting the conjunctiva. A scleral ring for combined surgery (Nishida scleral ring, Inami, Tokyo, Japan) was sutured to the sclera with 6-0 silk (Mani, Tochigi, Japan), and 10-0 polypropylene sutures were fixed to the loop of the IOL (CZ70BD®, Alcon, Fort Worth, TX ) on both sides using the cow-hitch technique.[23] PPV was performed using a 25-gauge (Constellation; Alcon, Fort Worth, TX) and a wide-viewing system (Resight 500; Carl Zeiss Meditec, Jena, Germany) in closed system (not open-sky) prior to trephination by retina specialists. Even in patients with a history of vitrectomy, the residual vitreous was checked and removed completely by shaving the vitreous base. We closed the infusion and reduced IOP just before trephination to prevent vitreous prolapse. The host cornea was cut using a trephine (Katena, Denville, USA) at 7.5 mm. The donor graft was prepared using a donor punch (Katena, Denville, USA) at either 7.75 mm or 8.0 mm. Using the open-sky PPV technique, the 10-0 polypropylene needles pierced the scleral flap 2.0 mm from the limbus. The donor graft was sutured using 10-0 nylon (Mani, Tochigi, Japan). The appropriate amount of cohesive ophthalmic viscosurgical devices (OPELEAD® HV [0.85] 1%) was used during the procedure.
Postoperative Care
Postoperative medications included 1.5% levofloxacin (Cravit) for 2 weeks, 0.1% betamethasone sodium phosphate (Sanbetasone; Santen) for 3 months, and 2% rebamipide ophthalmic solution (Mucosta; Otsuka, Japan, Tokyo) for 3 months, starting at 4 times per day and tapered thereafter. If necessary, glaucoma agents were applied.
Patients and Examinations
Besides the standard examination using slit-lamp microscopy, the following main outcomes were evaluated both preoperatively and postoperatively in all eyes: best spectacle-corrected visual acuity (BCVA) converted to logarithm of the minimal angle of resolution (logMAR) units, intraocular pressure (IOP, mmHg), and endothelial cell density (ECD, cells/mm2). Graft survival, complications, astigmatism, and the spherical equivalent were also evaluated (measured in dioptres [D]). The main outcome results for all the included cases are shown in Table 1.
Table 1. Patient Characteristics
Case
|
OD/OS
|
Aetiology
|
Type of surgery
|
Previous surgeries
|
Additional surgery
|
Pre
VA
|
Post
VA
|
1
|
OD
|
Bullous keratopathy
|
PKP+re-PPV
+IOL-suture+GDD
|
Trabeculectomy (failed),
PEA+PPV+Silicon oil
|
No
|
CF
|
20/2000
|
2
|
OD
|
Ocular trauma
|
PKP+re-PPV
+IOL-suture
|
PEA+PPV
|
GDD
|
20/29
|
20/23
|
3
|
OS
|
Ocular trauma (perforation)
|
PKP+re-PPV
+IOL-suture
|
PEA+PPV+Corneal suture
|
No
|
20/400
|
20/250
|
4
|
OS
|
Ocular trauma (perforation)
|
PKP+PPV
+IOL-suture
|
PEA+Corneal suture
|
No
|
20/2000
|
20/220
|
5
|
OS
|
Bullous keratopathy
|
PKP+re-PPV
+IOL-suture+GDD
|
PEA+PPV+Silicon oil,
Silicon oil removal
|
No
|
20/2000
|
20/250
|
6
|
OS
|
Bullous keratopathy
|
PKP+PPV
+IOL-suture
|
ECCE, PKP (twice)
|
No
|
20/100
|
20/29
|
7
|
OS
|
Ocular trauma
|
PKP+PPV
+IOL-suture
|
PKP
|
Trabeclectomy
|
20/400
|
20/100
|
8
|
OS
|
Bullous keratopathy
|
PKP+re-PPV
+IOL-suture
|
PEA+PPV+Corneal suture, PKP
|
GDD
|
20/2000
|
20/50
|
9
|
OD
|
Bullous keratopathy
|
PKP+PPV
+IOL-suture
|
PKP+ECCE
|
No
|
20/600
|
20/130
|
10
|
OS
|
Ocular trauma
|
PKP+PPV
+IOL-suture
|
PEA+PPV
+Silicon oil injection
+Corneal suture,
Silicon oil removal
|
No
|
20/2000
|
20/50
|
11
|
OS
|
Ocular trauma
|
PKP+PPV
+IOL-suture
|
PEA+Corneal suture
|
No
|
20/600
|
20/130
|
All patients underwent pars plana vitrectomy with penetrating keratoplasty and transscleral-sutured intraocular lens implantation.
OD, right eye; OS, left eye; Pre, preoperative; VA, best corrected visual acuity; Post, postoperative; PKP, penetrating keratoplasty; PPV, pars plana vitrectomy; IOL-suture, transscleral-sutured posterior chamber intraocular lens implantation; GDD, glaucoma drainage device; PEA, phacoemulsification and aspiration; ECCE, extracapsular cataract extraction; CF, counting fingers.
Statistical Analyses
Statistical analyses were performed using JMP Pro software version 14.0.0 (SAS Institute, Cary, NC, USA). Statistical significance was defined as p < 0.05. All average values are described as mean ± standard deviation. For the statistical analyses, BCVA was converted to logMAR units. Regarding poor visual acuity, the logMAR values were translated to light perception, logMAR = 2.8; perception of hand motions, logMAR = 2.3; and counting fingers, logMAR = 2.0 [24]. The Mann-Whitney U test was used to compare the preoperative and postoperative outcomes (BCVA, IOP, astigmatism).