Retinotomy refers to \"cutting\" or \"incising\" the retina, whereas retinectomy denotes \"excising\" the retina. Retinotomies and retinectomies aid in tackling traction and retinal shortening that persist following membrane dissection and scleral buckling. We performed a literature search using Google Scholar and PubMed, followed by a review of the references procured. All relevant literature was studied in detail and summarized. We discuss the indications of retinotomies and retinectomies for relaxing retinal stiffness, accessing the subretinal space for choroidal neovascular membrane, hemorrhage and abscess clearance, drainage retinotomies to allow retinal flattening, radial retinotomies to release circumferential traction, harvesting free retinal grafts, and prophylactic chorioretinectomies in trauma.

A peculiar tubular structure was found in the left eye (LE) of a 71-year-old patient with diabetic retinopathy, who already had undergone panretinal-photocoagulation, detected by spectral-domain optical coherence tomography (SD-OCT) as an incidental finding. The reason for consultation was vitreous hemorrhage of the fellow-eye. Fundoscopic examination of LE revealed three oval retinal holes separated by small bridges of retinal tissue, which corresponded to tubular structures visible in SD-OCT, surrounded by photocoagulation scars. Optical coherence tomography B-scans of these structures revealed a tubular arrangement of tissue, composed of solid parts and hyporeflective cystoid spaces. Intermittent choroidal hypertransmission was detected deep to the tubular structures indicating impaired or absent retinal pigment epithelium (RPE). OCT-Angiography was performed using the Zeiss Plex Elite 9000 swept source device (Zeiss Meditec, Dublin, California, USA). Within the tubular structures, no flow signal was detected. Segmentation at the level of the outer retina choriocapillaris (ORCC) indicated partially intact choriocapillaris in the areas of tubular structures and retinal holes. We hypothesize that the tubular structures mainly consist of neuro-retinal tissue and propose the term total neuro-retinal tubulation (TNT). We postulate that the edge curling effect that leads to the tubular arrangement relates to focal retinal tears caused by tractional forces acting on the retina in this case by scarring in response to laser photocoagulation. Since the retinal periphery is more prone to retinal tears, widefield OCT imaging modalities are likely to offer further insights into this newly described finding and shed greater light on the biomechanical properties of the retina. Histopathological investigation is required to make a valid statement about the histology of TNT.

To develop methods to simulate vitreous flow and traction during vitrectomy and qualify these methods using laboratory measurements.
Medium viscosity and phase treatment were adjusted to represent vitreous (Eulerian two-phase flow) or saline solution (single-phase Navier-Stokes flow). Retinal traction was approximated using a one-way fluid-structure interaction simulating cut vitreous volume coupled to a structural simulation of elastic stretching of a cylinder representing vitreous fibers entrained in the flow.
Simulated saline solution flow decreased, but vitreous flow increased with increasing cut rate, consistent with experimental trends observed for the 50/50 duty cycle mode. Traction simulations reproduced all trends in variation of traction force with changes in conditions. Simulations reproduced the majority of traction measurements within experimental error.
A scientific basis is provided for understanding how flow and traction vary with operational parameters. This model-based analysis serves as a \"virtual lab\" to determine optimal system settings to maximize flow efficiency while reducing traction.
The model provides a better understanding regarding how instrument settings can help control a vitrectomy procedure so that it can be made as efficient as possible (maximizing the rate of vitreous removal) while at the same time being made as safe as possible (minimizing retinal traction).