TREAT-AND-EXTEND REGIMENS WITH ANTI-VEGF AGENTS IN RETINAL DISEASES: A Literature Review and Consensus Recommendations.

PURPOSE: A review of treat-and-extend regimens (TERs) with intravitreal anti-vascular endothelial growth factor agents in retinal diseases. METHODS: There is a lack of consensus on the definition and optimal application of TER in clinical practice. This article describes the supporting evidence and subsequent development of a generic algorithm for TER dosing with anti-vascular endothelial growth factor agents, considering factors such as criteria for extension. RESULTS: A TER algorithm was developed; TER is defined as an individualized proactive dosing regimen usually initiated by monthly injections until a maximal clinical response is observed (frequently determined by optical coherence tomography), followed by increasing intervals between injections (and evaluations) depending on disease activity. The TER regimen has emerged as an effective approach to tailoring the dosing regimen and for reducing treatment burden (visits and injections) compared with fixed monthly dosing or monthly visits with optical coherence tomography-guided regimens (as-needed or pro re nata). It is also considered a suitable approach in many retinal diseases managed with intravitreal anti-vascular endothelial growth factor therapy, given that all eyes differ in the need for repeat injections. CONCLUSION: It is hoped that this practical review and TER algorithm will be of benefit to health care professionals interested in the management of retinal diseases.

Nature of subretinal fluid in patients undergoing vitrectomy for macular hole: a cytopathological and optical coherence tomography study.

BACKGROUND: Outer retinal defects (ORDs) may occur after surgical closure of full thickness macular holes (FTMH) and be associated with delayed visual recovery. This may be due to the nature of the subretinal fluid (SRF) cuff and/or the loss of retinal elements. METHODS: Vitrectomy with internal limiting membrane (ILM) peel was performed for FTMH. After fluid-air exchange, SRF was either aspirated from the hole (group 1) or left in situ (group 2). The SRF specimens obtained were examined by light microscopy and correlated with optical coherence tomography (OCT). RESULTS: In group 1, cellular material was found in 6 out of 12 cases. Photoreceptors were seen in 3 and macrophages in 3 cases. Nine of 12 holes closed and ORDs were seen in 3 of these. In group 2, 7 out of 8 holes closed, with 4 having ORD. There was no difference in visual acuity (LogMAR) for closed holes at 3 months between groups 1 (0.61, range 0.3-1) and 2 (0.51, range 0.3-0.78) nor between patients with ORD (0.57, range 0.3-1.0) or without ORD (0.57, range 0.3-1.0). CONCLUSIONS: SRF from FTMH may contain macrophages and photoreceptors. Such photoreceptor loss may contribute to reduced retinal function. ORDs occur commonly in spite of fluid aspiration, but their presence is still compatible with good vision. Aspiration of SRF did not appear to confer added benefit in this series.

Tamponade properties of double-filling with perfluorohexyloctane and silicone oil in a model eye chamber.

BACKGROUND: The use of perfluorohexyloctane as a heavier-than-water tamponade for long-term use is limited by its tendency to dispersion and associated intraocular inflammation. Double-filling with silicone oil and F6H8 produces a united, two-layer bubble, appearing as a single bubble. This has been proposed as a method of improving the utility of F6H8 as a tamponade. METHODS: A surface modified polymethylmethacrylate model eye chamber was double-filled with perfluorohexyloctane and silicone oil to approximate a 90% fill. The proportion of silicone oil was increased in a stepwise fashion. A qualitative comparison of surface contact at each stage was made. Chambers with one, two or no indent were used. Dispersion by agitation of the chamber was assessed. RESULTS: With less than 20% silicone oil it was difficult to force the two liquids to make contact. With more oil they united in the form of a single bubble joined at an interface. Once joined, the sides of the single bubble were drawn away from the wall of the chamber. As the proportion of silicone oil increased the area of lost contact increased and progressed inferiorly. Compared to F6H8 alone the double-fill reduced dispersion. CONCLUSION: Silicone oil and F6H8 can unite to form a single bubble that changes the effectiveness of either tamponade agent on their own. The double-fill needs to have enough silicone oil to form a single bubble, but this needs to be kept as low as possible to avoid progressive loss of lateral tamponade. It does not provide good simultaneous superior and inferior tamponade. The double-fill reduces dispersion.