The Bubble Eye Sign: Understanding the Radiological Imaging of Gas inside the Orbit

Gas, appears as radiolucent on X-ray, is normally absent in the orbit. However, intraocular surgeries occasionally utilize retained intraocular gas for tamponade effect. Intravitreal gas persists after retinal surgery, being confounded by the scleral shell of the operated eye, outlines the shape of the eyeball, and gives the characteristic bubble appearance on skull X-ray. This is different from orbital emphysema caused by orbital fracture when gas is located outside the globe but confined by the orbit, giving a crescent or concave shape over the superior orbit usually. Falls is common after intraocular retinal surgeries due to change of usual stereopsis, prolonged prone posturing, and other systemic comorbidities. By identifying the “Bubble Eye sign” described, attending physician should alert the presence of intravitreal gas, most commonly iatrogenic. Further ophthalmological history taking and examinations are thus indicated, instead of exposing patients to unnecessary radiation under computed tomography scan for orbital fracture investigation.

Computational fluid dynamics (CFD) simulation analysis on retinal gas cover rates using computational eye models

We investigated the change in the retinal gas cover rates due to intraocular gas volume and positions using computational eye models and demonstrated the appropriate position after pars plana vitrectomy (PPV) with gas tamponade for rhegmatogenous retinal detachments (RRDs). Computational fluid dynamic (CFD) software was used to calculate the retinal wall wettability of a computational pseudophakic eye models using fluid analysis. The model utilized different gas volumes from 10 to 90%, in increments of 10% to the vitreous cavity in the supine, sitting, lateral, prone with closed eyes, and prone positions. Then, the gas cover rates of the retina were measured in each quadrant. When breaks are limited to the inferior retina anterior to the equator or multiple breaks are observed in two or more quadrants anterior to the equator, supine position maintained 100% gas cover rates in all breaks for the longest duration compared with other positions. When breaks are limited to either superior, nasal, or temporal retina, sitting, lower temporal, and lower nasal position were maintained at 100% gas cover rates for the longest duration, respectively. Our results may contribute to better surgical outcomes of RRDs and a reduction in the duration of the postoperative prone position.

Incidence and Risk of Scleral-Fixated Akreos (AO60) Lens Opacification: A Case Series

Purpose: Postoperative hydrophilic intraocular lens opacification can lead to decreased vision and may require intraocular lens exchange. This study aims to identify the incidence of scleral-fixated Akreos AO60’s (Bausch + Lomb) lens opacification and risk factors for this phenomenon. Methods: This is a retrospective case series of all patients who underwent scleral-fixated Akreos AO60 lens at our institution between January 1, 2015 and December 31, 2019. The following data were recorded: age, sex, medical history, indication for Akreos AO60 implantation, laterality, ocular history, previous ocular surgical procedures, subsequent intraocular surgical procedures after the Akreos implantation, lens opacification, visual significance of opacification, and Akreos explantation. Intraoperative and postoperative complications were recorded. Main outcome measures were the overall incidence of Akreos lens opacification as well as the incidence of these eyes undergoing subsequent intraocular surgery. Results: A total of 262 eyes of 257 patients underwent Akreos lens implantation. Overall, 2% (5 of 262) developed lens opacification. Two patients had Descemet stripping automated endothelial keratoplasty (DSAEK) concurrently with Akreos implantation. One patient underwent subsequent Baerveldt glaucoma implantation and DSAEK. The fourth patient had vitrectomy with sulfur hexafluoride gas followed by DSAEK. This represents a 25% (4 of 16) opacification rate among all patients who underwent DSAEK ( P ≤ .01, Fisher exact test). One patient developed opacification after undergoing 2 vitrectomies for retinal detachment in the absence of DSAEK. Conclusions: Akreos lens opacification can be visually significant and may occur after a retinal or corneal procedure that involves the use of intraocular gas or air.

Surgical management of a case of contractile peripapillary staphyloma with retinal detachment and macular hole

A healthy 4-year-old male presented a fundus examination with a unilateral contractile peripapillary staphyloma surrounded by redundant retina and retinal pigment epithelium atrophy. Five years later, best-corrected visual acuity decreased to hand motion due to a retinal detachment with macular hole. One month after first vitrectomy, scleral buckle and intraocular gas, retina re-detached. Second surgery was performed with silicon oil tamponade and lensectomy without intraocular lens (IOL). Subretinal silicon oil was detected at the third month of follow-up when vitrectomy, inferior retinectomy, and laser photocoagulation of temporal border of staphyloma with silicon oil tamponade were performed. The retina remained attached and best-corrected visual acuity was 20/600 with intraocular silicon oil. A fourth surgery was performed for emulsified silicon oil extraction replaced with intraocular gas. At 6 months of follow-up, the retina re-detached again. This is a challenging vitreoretinal surgery in which re-detachments were due to retinal folds around the contractile staphyloma that raised macular hole. This is the first report of the combined presentation of contractile peripapillary staphyloma, retinal detachment and macular hole with a long-time follow-up period of years.

Calcification of hydrophilic acrylic intraocular lenses following secondary surgical procedures in the anterior and posterior segments

AimsTo report 15 cases of intraocular lens (IOL) calcification following intraocular surgery and to identify common risk factors.MethodsA retrospective case review of patients with IOL calcification reported from the Royal Victorian Eye and Ear Hospital, Melbourne, Australia, and six surgeons in private practice in the Australian states of Victoria, New South Wales and Queensland.Results15 cases of IOL calcification were identified. Eight cases were in hydrophilic acrylic IOLs and seven in hydrophilic acrylic IOLs with hydrophobic surface properties. Five cases occurred following intraocular injection of gas during endothelial keratoplasties. Two cases occurred following pars plana vitrectomy where gas was used. The remaining eight cases did not involve the injection of any intraocular gas; six cases were following trabeculectomy surgery, and two cases were after insertion of a ‘piggyback’ sulcus IOL. In each case, the calcification had a characteristic pattern, being centrally placed in the pupillary zone, mainly affecting the anterior lens surface.ConclusionThe aetiology of IOL calcification is not fully understood, although there are known risk factors such as using hydrophilic acrylic materials and the use of intraocular gas. Surgical consideration of a patient’s ocular comorbidities before IOL implantation is an important tool to mitigate some of this risk.

Opacification of hydrophilic intraocular lenses associated with vitrectomy and injection of intraocular gas

ObjectiveTo report 11 cases of intraocular lens (IOL) opacification after pars plana vitrectomy (PPV) involving intravitreal gas injection.Methods and analysisEleven cases of hydrophilic IOLs that opacified following PPV with intravitreal gas injection are described. Eight IOLs were explanted and analysed by light microscopy and scanning electron microscopy. Staining with alizarin red and von Kossa stains, as well as energy dispersive X-ray spectroscopy (EDX) were performed. Three IOLs were not explanted. The surgeons attached the clinical data.ResultsThe IOLs were hydrophilic acrylic produced by six manufacturers. Six patients underwent primarily phacoemulsification with IOL implantation. PPV with intravitreal gas injection was performed 3 months–6 years afterwards. The other five patients underwent combined phacoemulsification with IOL implantation and PPV with intravitreal gas injection. IOL opacification was recorded 1 month –6 years after PPV. In eight patients, the IOLs were explanted 1 month–9 years after opacification was noticed. In three patients, the opacified IOL was not explanted. IOLs had opacified mainly anteriorly at the pupillary entrance or capsulorhexis opening. Light microscopy demonstrated granular surface deposits on the IOLs that stained positive for calcium by alizarin red and von Kossa stains. EDX analysis of the deposits detected calcium and phosphorus.ConclusionsHydrophilic acrylic IOLs can opacify due to calcium deposition after PPV and intravitreal gas injection and may require IOL explantation. A hydrophobic IOL may be preferred when a simultaneous phacoemulsification and vitrectomy with intravitreal gas is performed.

Complications Associated with the Use of Expandable Gases in Vitrectomy

Intraocular gases have been used in vitreoretinal surgery for over 40 years. The aim of this study was to review the complications related to the use of expandable gases in vitrectomy and their management. A PubMed, Cochrane Library, and Embase search was conducted using the terms “intraocular gas” and “vitrectomy for retinal detachment.” Of the articles retrieved by this method, all publications in English and abstracts of non-English publications were reviewed. Intraocular pressure elevation was reported in up to 58.9% patients after vitrectomy with expandable gas administration for retinal detachment. Vitreoretinal surgery is known to induce cataract development. With that, cataract progression is associated with lens exposure to intraocular gas, the duration of such exposure, patient’s age, and the magnitude of vitreous removal. With intraocular gas, the posterior surface of the lens becomes a strongly refractive factor, resulting in high myopia and temporary vision impairment. Other complications related to the use of expandable gases include anterior chamber and subconjunctival gas displacement. Single reports on subretinal and cranial gas migration were published. In vitrectomy for uncomplicated retinal detachments, attempts to shift from expandable gases towards air are observed. Nevertheless, gas tamponade remains a reasonable choice for patients suffering from retinal detachment.