Vitrectomy

The surgical management of macular holes has been a subject of controversy in recent years. Various techniques such as vitrectomy, membrane peeling, and gas tamponade with or without transforming growth factor-beta 2, and recently the use of autologous platelets have produced closure rates from 58% to 96%, depending on the stage of the hole. The authors present preliminary results in a study of 19 consecutive patients with stage 3 or stage 4 macular hole who underwent vitrectomy followed by placement of an absorbable partially cross-linked gelatin plug in the macular hole. The vitreous cavity was filled with a nonexpanding gas or air alone; the patient was instructed to maintain prone positioning for 2-3 days. Anatomic attachment of the edges of the macular hole was achieved in 19 out of 19 patients with a minimum follow-up period of 6 months (average 11.5 months). A cross-linked gelatin plug can effectively reattach the edges of macular holes of stages 3 and 4. Its use is recommend...

This study evaluates the efficiency of fluid-air exchange on the reattachment of the retina and clarifies the possibility that a posterior retinotomy is a cause for intra- and postoperative complications. A consecutive series of 211 eyes with retinal detachments due to P.V.R. (47%), diabetic traction, perforating trauma, macular hole or giant tears is presented. All eyes underwent pars plana vitrectomy, fluid-air exchange, internal drainage of subretinal fluid, laser endophotocoagulation and scleral buckling of the tears; 56% of the eyes were phakic and 55% underwent a posterior retinotomy, 54% underwent tamponade with C3F8 and 46% with silicone oil. Intraoperatively the retina was completely flattened in 91% cases. The causes of incomplete reattachment were residual membranes (6.6%), poor visualization (1.4%) and suprachoroidal hemorrhage (1%). These complications were isolated as being the cause of the bad final results (p < 0.001). Postoperatively, the retina remained attached in 66% of cases after the first procedure and with further surgery in 81% (mean follow up 16 months). Best corrected visual acuity was improved in 73% of eyes, unchanged in 17%, and worse in 10%. Complications were retraction of the retinotomy site in 3 cases and peripheral choroidal hemorrhage in 4 cases. We concluded that fluid air exchange with internal subretinal fluid drainage was an efficient and safe technique even if a posterior retinotomy was necessary.

To report ocular perforation that occurred during retrobulbar injection in 7 highly myopic eyes. Seven patients with a diagnosis of globe injury during retrobulbar injection for ocular anesthesia before cataract surgery were managed by vitreoretinal surgery. All injections were performed by ophthalmologists. The surgeon recognized the perforation in 4 cases at the time of injection. The preoperative vision was hand motion perception in 4 eyes and light perception in 3 eyes. All patients underwent vitreoretinal surgery because of the presence of vitreous hemorrhage and/or retinal detachment diagnosed by funduscopy or ultrasonography. At the time of surgery, all eyes had vitreous hemorrhage and 4 eyes had rhegmatogenous retinal detachment. The number of vitreoretinal procedures performed was: 1 procedure in 4 patients, 2 procedures in 2 patients, and 3 procedures in 1 patient. The period of follow-up ranged from 4 months to 4 years, averaging 20 months. At the end of the follow-up per...

The importance of gravitational instability in determining the emulsification of vitreal tamponades is discussed. Theoretical results and numerical simulations indicate that the spontaneous formation of water-silicon oil is a rare event and that the very low concentration of surface active agents cannot justify the systematic formation of emulsions. The gravitational instabilities seem to play the main role. Our theoretical results seem in agreement with the experimental evidences; furthermore they indicate a future research line for the improvement of endotamponades. Indeed, the use of biodegradable antifoam may avoid the formation of bubbles and delay the formation of emulsions.

The purpose of the article is to describe the optics of the contact wide-angle lens system with stereo-reinverter for vitreous surgery. A panoramic viewing system is made up of two components; an indirect ophthalmoscopy lens system for fundus image viewing, which is placed on the patient's cornea as a contact lens, and a separate removable prism system for reinversion of the image mounted on the microscope above the zooming system. The system provides a 104° field of view in a phakic emmetropic eye with minification, which can be magnified by the operating microscope. It permits a binocular stereoptic view even through a small pupil (3 mm) or larger. In an air-filled phakic eye, field of view increases to approximately 130°. The obtained image of the patient's fundus is reinverted to form true, erect, stereoscopic image by the reinversion system. In conclusion, this system permits wide-angle panoramic view of the surgical field. The contact lens neutralizes the optical irregularities of the corneal surface and allows improved visualization in eyes with irregular astigmatism induced by corneal scars. Excellent visualization is achieved in complex clinical situations such as miotic pupils, lenticular opacities, and in air-filled phakic eyes.

Background: The Lenstar LS 900 (Haag-Streit AG, Koeniz, Switzerland) is an optical biometer, and its measurements are highly repeatable and precise in cataractous eyes. This study investigated changes in biometric parameters, including axial length (AL), anterior chamber depth (ACD), lens thickness (LT), vitreous cavity depth (VD), and central corneal thickness (CCT) before and after three-port 23-Gauge pars plana vitrectomy with silicone oil tamponade. Methods: This was a prospective follow-up study. Patients who were scheduled for surgery underwent a detailed slit-lamp examination and objective cycloplegic refraction preoperatively. In eligible cases, the Lenstar LS 900 was used to measure biometric parameters. At the 1-month postoperative follow-up, we repeated the same assessments for the silicone oil (SO)-filled eyes. Data were analyzed to assess the significance of changes and to test the possible correlation of values between the two time points. Results: Twenty-three patients with a mean ± standard deviation age of 60 ± 12 years completed the study. Postoperatively, we found a significant increase in AL and a decrease in ACD and CCT (all P < 0.05), with no significant changes in LT and VD. A significant correlation was found for ACD, CCT, and cylinder values between the two time points (all P < 0.05). Postoperatively, the spherical and cylindrical components of refraction demonstrated a hyperopic shift, but did not change statistically significantly. Conclusions: The Lenstar LS 900 underestimated the ACD and overestimated the AL in SO-filled eyes when comparing pre-and postoperative values, in phakic as well as pseudophakic eyes. In planning for cataract surgery in this group of patients, it is more reasonable to calculate IOL power based on the biometric data of the fellow eye, although this may not eliminate possible errors. Further studies with a larger sample size, longer follow-up, and robust study design are necessary to confirm our preliminary results.

Background: A study of the characteristics and the results obtained in 99 consecutive eyes operated on for rhegmatogenous retinal detachment associated with aphakia or pseudophakia in order to find the predictive factors of poor anatomical and functional results. Methods: The authors retrospectively reviewed the files of 99 consecutive cases of aphakic and pseudophakic retinal detachment operated on by the same surgeon between January 1992 through July 1993 with a minimum follow-up of 6 months. Multivariate and chi square analysis were carried out. Results: Of the pseudophakic eyes, 25 had an anterior chamber lens and 48 had a posterior chamber lens. The posterior capsule was disrupted using a Yag laser in 58% of those with an posterior chamber lens but only 14% of them developed detachment within 6 months. The rate of vitreous loss was 27% with 5% in case of intracapsular extraction, 31% in case of extracapsular extraction and 54% in case of phacoemulsification. PVR was present in 30% of the patients and 51% of detachments occurred more than 24 months as a mean after cataract surgery. The overall anatomic reattachment rate was 88% with no significant difference between the aphakic and the pseudophakic patients, either with an anterior chamber of posterior chamber lens. Visual results were significantly worse in the anterior chamber lens group and in the aphakic eyes (P < 0.02). Negative prognostic indicators for reattachment included poor preoperative vision, extension of the retinal detachment to the macula (P < 0.05) and grades B, C or D proliferative vitreoretinopathy (P < 0.01). In addition to the above factors, eyes with vitreous loss, anterior chamber lens, aphakia and a larger extent of the retinal detachment had a poor visual outcome. Conclusion: Most aphakic or pseudophakic retinal detachment can now be reattached with either scleral or vitreo retinal surgery. The main difficulties are the localisation of the breaks and the treatment of PVR. Indirect ophthalmoscopy associated with vitrectomy does well in cases of an opacified posterior capsule. In cases of severe PVR long term internal tamponade either with C3F8 or silicone oil improves anatomical results but the functional results remain inferior.

Retinal photocoagulation and vitrectomy both reduce diabetic macular edema and neovascularization in diabetic retinopathy. We suggest that this clinical effect is based on the effect these treatment modalities have on retinal oxygenation, and we present a theory to explain why retinal photocoagulation and vitrectomy influence edema and neovascularization in diabetic and other ischemic retinopathies.

To evaluate foveal microstructural changes in eyes with anatomically successful repair of rhegmatogenous retinal detachments (RRDs). Retrospective, consecutive, observational case series. Fifty-three eyes of 51 consecutive patients with macula-on RRDs (15 eyes) or macula-off RRDs (38 eyes) after anatomically successful surgical repair. A microscopic fundus examination was conducted followed by Fourier-domain optical coherence tomography (FD-OCT) to assess the postoperative foveal microstructure. The correlation between the postoperative best-corrected visual acuity (BCVA) and microstructural findings at the fovea was evaluated. Images of the foveal microstructure obtained by FD-OCT and the BCVA measured on the same day. We obtained FD-OCT images a mean of 10.3+/-7.3 months (range, 1-25) postoperatively. Foveal anatomic abnormalities were detected in 33 eyes (62%); disruption of the junction between the photoreceptor inner and outer segments (IS/OS) in 23 eyes (43%), of which 9 eyes (39%) had a disrupted external limiting membrane (ELM); residual subretinal fluid in 6 eyes (11%), epiretinal membranes in 12 eyes (23%), and cystoid macular edema in 2 eyes (4%). Disruption of the photoreceptor IS/OS junction was observed only in macula-off eyes, whereas other microstructural abnormalities were observed in both macula-on and macula-off eyes. In preoperative macula-off eyes, the postoperative BCVA was significantly correlated with the integrity of the photoreceptor IS/OS and ELM signals detected by FD-OCT postoperatively (r=0.805; P&amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001). Of the 16 eyes followed by FD-OCT, the photoreceptor IS/OS junction was restored in 7 (64%) of the 11 eyes with a disrupted back-reflection line from the IS/OS junction, but without disrupted ELM signals at the initial examination. Of the 5 eyes with disrupted back-reflection lines from both IS/OS junction and ELM at the initial examination, the photoreceptor layer was not restored completely during the follow-up period in any eyes. After anatomically successful RRD repair, FD-OCT is a valuable, noninvasive tool for evaluating foveal microstructural changes. The integrity of the photoreceptor IS/OS junction and ELM signals detected by FD-OCT may account for visual restoration in patients with preoperative macula-off RRDs. Preservation of the ELM postoperatively may predict the subsequent restoration of the photoreceptor layer.