Table 2.

Characteristics of included studies [ordered by study ID]

Mulvihill 1996
Methods	Study design: parallel group randomized controlled trial Number randomized: 20 participants total 10 participants in the pneumatic retinopexy group 10 participants in the scleral buckle group Exclusions after randomization: none reported Unit of analysis: individual (1 eye of each participant included) Number analyzed: 20 participants total 10 participants in the pneumatic retinopexy group 10 participants in the scleral buckle group Losses to follow-up: none reported Power calculation: not reported
Participants	Country: Ireland Age: not reported Gender: not reported Inclusion criteria: participants diagnosed with rhegmatogenous retinal detachment fulfilling certain criteria: single retinal break or a small group of breaks, not larger than 1 clock hour of retina in size break or breaks located within the superior 8 clock hours of retina absence of significant proliferative vitreoretinopathy absence of uncontrolled glaucoma person able to maintain postoperative head posturing, if required Exclusion criteria: not reported Equivalence of baseline characteristics: not reported
Interventions	Intervention 1: pneumatic retinopexy Intervention 2: scleral buckle “Pneumatic retinopexy was performed under local anaesthesia in the operating theatre in all cases. Following peribulbar anaesthesia, the eye was softened using Honan’s Balloon and the periorbital skin cleaned with 0.1% chlorhexidine and then draped. The retinal breaks were identified and gas then injected into the vitreous cavity 4 mm posterior to the limbus using a 30-gauge needle. The gas used was either 0.6 ml of sulphur hexafluoride (SF6) or 0.3 ml of perfluoropropane (C3F8). Following rejection of gas the patency of the central retinal artery was evaluated with the indirect ophthalmoscope. The retinal break was then sealed using either transconjunctival cryopexy or indirect (argon) laser. Cryopexy was used when a satisfactory reaction could not be obtained with laser. In some large bullous RDs the procedure was performed in two stages: the retina was allowed to flatten after gas injection and then the retinal break was sealed one to two days later. After gas injection the intraocular pressure was checked by applanation tonometry three and six hours later. Postoperatively the participants were instructed to posture for at least sixteen hours per day and for at least four days so the retinal breaks were uppermost, tamponaded by the intraocular gas bubble. Topical antibiotic/steroid (Betnesol-N) was administered for four weeks postoperatively. Briefly, scleral buckle was performed as follows. The conjunctiva and Tenon’s capsule were opened and the subretinal fluid drained via an opening in the sclera to allow the retina to move back into position after injection of sterile air into the vitreous cavity. The retinal break was then sealed with trans-scleral cryopexy. Finally, a hard silicone explant was sutured onto the sclera in the region of the retinal break to create a permanent scleral indentation. All of the scleral buckle procedures were carried-out under general anaesthesia.” Length of follow-up: Planned: not reported Actual: average follow-up 16.7 months (range 5 to 27 months) in the pneumatic retinopexy group and 16.0 months (range 8 to 23 months) in the scleral buckle group
Outcomes	Primary outcome: reattachment of the retina Secondary outcomes: visual acuity, recurrence of retinal detachment, and adverse events Intervals at which outcomes assessed: not reported
Notes	Type of report: published article Funding sources: not reported Disclosures of interest: not reported Study period: November 1991 to February 1994 Subgroup analyses: none reported Publication language: English
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of randomization not reported.
Allocation concealment (selection bias)	Unclear risk	“Participants were randomised by a closed envelope technique into one of two groups.”
Masking of participants and personnel (performance bias)	Unclear risk	Masking of participants and personnel not reported, but surgeons could not have been masked
Masking of outcome assessment (detection bias)	Unclear risk	Masking of outcome assessors not reported.
Incomplete outcome data (attrition bias) All outcomes	Low risk	All participants included and randomized were analyzed.
Selective reporting (reporting bias)	Unclear risk	Study protocol not available.
Other bias	Unclear risk	Funding source not reported.
Tornambe 1989
Methods	Study design: parallel group randomized controlled trial Number randomized: 200 eyes of 198 participants total; number not reported by treatment group Exclusions after randomization: none reported Unit of analysis: individual (1 eye of each participant included, except for 2 participants for which both eyes were included) Number analyzed: 198 eyes of 196 participants total; 103 eyes in the pneumatic retinopexy group (41 eyes with macular-attached; 62 eyes with macular-detached) 95 eyes in the scleral buckle group (35 eyes with macular-attached; 60 eyes with macular-detached) Losses to follow-up: 2 eyes of 2 participants; 1 participant died of a myocardial infarction 2 months after scleral buckle and 1 was lost to follow-up Power calculation: not reported
Participants	Country: United States Age: not reported Gender: 64/103 (62%) men and 39/103 (38%) women in pneumatic retinopexy group; 65/95 (68%) men and 30/95 (32%) women in scleral buckle group Inclusion criteria: “(1) A single break no larger than 1 clock hour located in the superior 8 clock hours of the ocular fundus, or a group of small breaks within 1 clock hour (2) Media sufficiently clear to (a) rule out the presence of other retinal breaks; (b) determine macula attachment/detachment; (c) not significantly reduce visual acuity (3) Patient willingness to enter into the randomized study (4) Stated availability for at least 6 months follow-up (5) Eye is judged suitable for treatment by either procedure (6) All eyes must have a history of good vision before retinal detachment (to facilitate statistical evaluation of postoperative visual acuity) (7) Macula-on eyes with clear media must have corrected visual acuity of 20/50 or better (at least 35 letters on the ETDRS chart) (8) Macula-off eyes must have a corrected visual acuity worse than 20/50 (< 35 letters on the ETDRS chart) (9) The shortest diameter of the detached area must be at least 6 DD.” Exclusion criteria: “(1) Proliferative vitreoretinopathy, grade C or D (2) Glaucoma which is medically uncontrolled or in which the cup-disc ratio exceeds 0.6 (3) Retinal breaks in the inferior 4 clock hours of the fundus (4) Inadequate physical and/or mental competence to maintain the required postoperative head position.” Equivalence of baseline characteristics: yes, based on gender, lens status, capsule detachment (absent/open), myopia, vitreous hemorrhage, days since macular detachment, and visual acuity
Interventions	Intervention 1: pneumatic retinopexy Intervention 2: scleral buckle “When pneumatic retinopexy was used, the surgeon recorded the type and volume of gas injected (the type of gas selected was not randomized), the number of cryopexy or laser photocoagulation applications, the incidence and duration of central retinal artery closure, paracentesis, intraocular pressures at 5, 10, 20, 30 and 60 minutes after gas introduction, and all intraoperative complications. When scleral buckle was used, the surgeon recorded the type of buckle material, the number of cryopexy applications, drainage of subretinal fluid, the incidence and duration of central retinal artery closure, paracentesis, the type and volume of gas injected, and all intraoperative complications.” Length of follow-up: Planned: not reported Actual: 24 months
Outcomes	Primary and secondary outcomes not specified Outcome, as define d: surgical success (retinal reattachment at 6 months after 1 surgical intervention), visual acuity, recurrence of retinal detachment, morbidity, and adverse events Intervals at which outcomes assessed: surgical success (6, 12, and 24 months), visual acuity (1, 6, 12, and 24 months), and adverse events (1, 3, 7, and 14 days; 1, 2, 4, and 6 months)
Notes	Type of report(s): published articles and conference abstract Funding sources: not reported Disclosures of interest: not reported Study period: not reported Subgroup analyses: macular-attached and macular-detached (participants stratified before being randomized for treatment) Publication language: English
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of randomization not reported; however, “A separate randomization schedule was prepared for each center.”
Allocation concealment (selection bias)	Unclear risk	Allocation concealment before randomization not reported.
Masking of participants and personnel (performance bias)	Unclear risk	Masking of participants and personnel not reported, but surgeons could not have been masked
Masking of outcome assessment (detection bias)	Unclear risk	Masking of personnel assessing retinal reattachment not reported; “Visual acuity was evaluated by an examiner, in a masked manner, who was unacquainted with the case.”
Incomplete outcome data (attrition bias) All outcomes	Low risk	2 eyes (2 participants) of 198 eyes excluded from the analysis
Selective reporting (reporting bias)	Unclear risk	Study protocol not available.
Other bias	Unclear risk	Funding source not reported.

DD: disc diameter

ETDRS: Early Treatment Diabetic Retinopathy Study

RD: retinal detachment