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PurposeSurgical innovations are necessary to improve patient care. After an initial exploratory phase novel surgical technique should be compared with alternative options or standard care in randomized clinical trials (RCTs). However surgical RCTs have unique methodological challenges. Our study sought to investigate key aspects of the design, conduct and reporting of RCTs of novel surgeries.DesignSystematic ReviewMethodsThe protocol was prospectively registered in PROSPERO (CRD42021253297). RCTs evaluating novel surgeries for cataract, vitreoretinal, glaucoma and corneal diseases were included. Medline, EMBASE, Cochrane Library and Clinicaltrials.gov were searched. The search period was January 1, 2016, to June 16, 2021.ResultsFifty-two ophthalmic surgery RCTs were identified in the fields of glaucoma (n=12), vitreoretinal surgery (n=5) cataract (n=19) and cornea (n=16). A description defining the surgeon's experience or level of expertise was reported in 30 RCTs (57%); and was presented in both, control and intervention groups, in eleven (21%). Specification of number of cases performed in the particular surgical innovation being assessed prior to the trial was reported in 10 RCTs (19%); and an evaluation of quality of the surgical intervention in seven (13%). Prospective trial registration was recorded in 12 RCTs (23%), retrospective registration in 13 (25%) and there was no registration record in the remaining 28 (53%) studies.ConclusionImportant aspects of the study design such as surgical learning curve, surgeon's previous experience, quality assurance, and trial registration details were often missing in novel ophthalmic surgical procedures. The IDEAL framework aims to improve the quality of study design.

COVID-19 has placed unprecedented pressure on health systems globally, whereas simultaneously stimulating unprecedented levels of transformation. Here, we review digital adoption that has taken place during the pandemic to drive improvements in ophthalmic clinical care, with a specific focus on out-of-hospital triage and services, clinical assessment, patient management, and use of electronic health records. We show that although there have been some successes, shortcomings in technology infrastructure prepandemic became only more apparent and consequential as COVID-19 progressed. Through our review, we emphasize the need for clinicians to better grasp and harness key technology trends such as telecommunications and artificial intelligence, so that they can effectively and safely shape clinical practice using these tools going forward.

Objective: To assess the patterns of patient generated aerosol in the context of ophthalmic surgery and ophthalmic examinations. To inform medical teams regarding potential hazards and suggest mitigating measures. Methods: Qualitatively, real-time time videography assessed exhalation patterns from simulated patients under different clinical scenarios using propylene glycol from an e-cigarette. Quantitatively, high-speed Schlieren imaging was performed to enable high resolution recordings analysable by MATLAB technical computing software. Results: Without a face mask, the standard prior to COVID 19, vapour was observed exiting through the opening in the drape over the surgical field. The amount of vapour increased when a surgical mask was worn. With a taped face mask, the amount of vapour decreased and with inclusion of a continuous suction device, the least amount of vapour was seen. These results were equivocal when the patient was supine or sitting upright. High-speed Schlieren imaging corroborated these findings and in addition showed substantial increase in airflow egress during coughing and with ill-fitting face masks. Conclusion: Advising patients to wear a surgical mask at the time of ophthalmic interventions potentially contaminants the ocular field with patient generated aerosol risking endophthalmitis. Surgeon safety can be maintained with personal protective equipment to mitigate the increased egress of vapour from the surgical drape and taping, with or without suction is advisable, whilst meticulous hygiene around lenses is required at the time of slit lamp examination.

Albinism defines a group of genetic diseases which result from disordered melanin biosynthesis. Proliferative diabetic retinopathy (PDR) results from poorly controlled type 1 or 2 diabetes mellitus (DM) and can lead to blindness due to progressive neovascularisation. However, the treatment of PDR in patients with ocular/oculocutaneous albinism may be more challenging. In this study, we compared a group of patients with albinism and PDR, to a group with albinism and diabetes mellitus but no PDR, to examine the long-term implications.Retrospective observational study included all patients with ocular albinism (OA) or oculocutaneous albinism (OCA) and DM who presented at a single specialist centre. Participants were allocated into either group 1 (eyes with PDR) or group 2 (all eyes without PDR). Statistical analysis was performed using SPSS V26.0. Between-group differences were investigated.Outcome data was available for 5 eyes from 3 participants in group 1 and 26 eyes from 13 participants in group 2. Despite interventions, a large and significant difference in vision at follow-up was observed between group 1 and group 2 (mean change in visual acuity: 1.11 (± 1.00) versus - 0.15 (± 0.46), respectively; p = 0.0001).PDR is associated with poor long-term prognosis despite interventions for patients with albinism. Those without PDR appear to maintain stable vision. Alternative treatments for PDR and its complications may be required in this population. Measures to prevent the development of diabetic eye disease and progression towards PDR should be employed at an early stage.

To analyze the outcomes of revision surgery for idiopathic full-thickness macular holes that have failed to close after primary surgery, and also to assess factors predicting success and to review the relative effect of adjunctive surgical techniques.A multicenter retrospective study. Anatomical closure rates and visual acuity change between pre and postrevision surgery were assessed. Hole size, age, symptom duration, surgical interval, and reduced hole size were analyzed as predictive factors for success. Effectiveness of adjunctive surgical techniques was reviewed.Seventy-seven eyes were included in the study. Anatomical closure was achieved in 71% (55/77) cases. There was a median gain of 11 Early Treatment of Diabetic Retinopathy Score letters in all holes and 14 letters in closed holes. Full-thickness macular holes that increased in size by more than 10% following primary surgery had a closure rate of 50% compared with 80% in holes that reduced by 10% or stayed the same (P = 0.015). Increasing hole size is associated with a modest reduction in odds of closure (odds ratio = 0.99; P = 0.04). Surgical interval2 months is not associated with better outcomes compared with2 months (P = 0.14).Revision surgery for full-thickness macular holes that have failed to close after primary surgery is associated with high closure rates and significant visual gains.

To investigate the relationship between vitreomacular traction (VMT) width, foveal floor width (FFW) and other anatomical characteristics between eyes of patients with VMT. Retrospective observational study of unilateral and bilateral VMT cases from two specialist ophthalmic centres in the United Kingdom (UK) between 2016 and 2018. For unilateral VMT cases: VMT width in the affected eye and FFW in the non-affected fellow eye were measured. In bilateral VMT cases: VMT width in both eyes was measured. In all cases, the presence of any associated inner or outer retinal, and vitreoretinal interface (VRI) changes, including epiretinal membrane, was also documented. 88 patients fulfilled the study criteria: 57 having unilateral and 31 bilateral VMT. For unilateral VMT cases, log (VMT) width was significantly correlated with FFW (r = 0.347, p = 0.008). Using stepwise linear regression, FFW (p = 0.004) and VRI changes (p = 0.03) were both significantly associated with VMT width with a R2 of 0.21. In bilateral VMT cases, there was strong positive correlation between log (VMT) width (r = 0.88, p < 0.001), and the presence of any VRI (r = 0.90, p < 0.001) or outer retinal changes (r = 0.50, p < 0.001) between the two eyes. These findings suggest that individual variations in foveal morphology as measured by the FFW, along with the presence of vitreoretinal interface changes, are associated with the extent of VMT width. VMT width, VRI and outer retinal changes were also highly correlated between eyes in bilateral VMT, suggesting that individual patient factors, which may be genetic or acquired, determine their presence and extent.

Varied options are available for the implantation of secondary intraocular lens implants in the absence of zonular or capsular support. Loss of the capsule can occur in the context of complicated cataract surgery, trauma or inherited conditions such as Marfan syndrome or pseudoexfoliation. Approaches to overcome this include optical measures such as the use of spectacles or contact lenses, and surgical therapy incorporating the use of anterior chamber, iris-fixated or scleral-fixated lenses. Surgical techniques to implant scleral-fixated lenses have undergone various modifications, since the first publication of sutured intrascleral fixation described in the 1980s. However, despite the advances in surgical techniques, studies are limited either by their retrospective nature, small sample size and most importantly small duration of follow-up. This comprehensive review aims to amalgamate the evolution of various surgical techniques with regards to intrascleral lens fixation and suggests areas for future development.摘要: 经巩膜缝线固定的眼内人工晶状体植入术——手术技术的演变与未来发展摘要在缺乏晶状体悬韧带或囊膜支撑的情况下, 二期人工晶状体植入有多种选择。在复杂性白内障手术、外伤或遗传性疾病 (如马凡氏综合征或假性脱落) 的白内障手术中, 可能会出现晶状体囊膜缺失的情况。而光学治疗措施 (佩戴框架眼镜或隐形眼镜) 以及手术方法 (结合使用前房、虹膜固定或巩膜固定的人工晶状体) 可以解决问题。自20世纪80年代首次发表关于巩膜内固定术的文章以来, 植入经巩膜缝线固定人工晶体的外科技术经历了各种各样的改进。然而, 尽管外科手术技术有了进步, 但由于研究为回顾性、样本量小和最重要的随访时间短, 研究结果不尽人意。本综述旨在深度探讨经巩膜缝线固定人工晶状体植入术的进展, 并对今后的发展方向提出建议。#32463;#24041;#33180;#32541;#32447;#22266;#23450;#30340;#30524;#20869;#20154;#24037;#26230;#29366;#20307;#26893;#20837;#26415;#8212;#8212;#25163;#26415;#25216;#26415;#30340;#28436;#21464;#19982;#26410;#26469;#21457;#23637;#25688;#35201;#22312;#32570;#20047;#26230;#29366;#20307;#24748;#38887;#24102;#25110;#22218;#33180;#25903;#25745;#30340;#24773;#20917;#19979;#65292;#20108;#26399;#20154;#24037;#26230;#29366;#20307;#26893;#20837;#26377;#22810;#31181;#36873;#25321;#12290;#22312;#22797;#26434;#24615;#30333;#20869;#38556;#25163;#26415;#12289;#22806;#20260;#25110;#36951;#20256;#24615;#30142;#30149;#65288;#22914;#39532;#20961;#27663;#32508;#21512;#24449;#25110;#20551;#24615;#33073;#33853;#65289;#30340;#30333;#20869;#38556;#25163;#26415;#20013;#65292;#21487;#33021;#20250;#20986;#29616;#26230;#29366;#20307;#22218;#33180;#32570;#22833;#30340;#24773;#20917;#12290;#32780;#20809;#23398;#27835;#30103;#25514;#26045;#65288;#20329;#25140;#26694;#26550;#30524;#38236;#25110;#38544;#24418;#30524;#38236;#65289;#20197;#21450;#25163;#26415;#26041;#27861;#65288;#32467;#21512;#20351;#29992;#21069;#25151;#12289;#34425;#33180;#22266;#23450;#25110;#24041;#33180;#22266;#23450;#30340;#20154;#24037;#26230;#29366;#20307;#65289;#21487;#20197;#35299;#20915;#38382;#39064;#12290;#33258;#50;#48;#19990;#32426;#56;#48;#24180;#20195;#39318;#27425;#21457;#34920;#20851;#20110;#24041;#33180;#20869;#22266;#23450;#26415;#30340;#25991;#31456;#20197;#26469;#65292;#26893;#20837;#32463;#24041;#33180;#32541;#32447;#22266;#23450;#20154;#24037;#26230;#20307;#30340;#22806;#31185;#25216;#26415;#32463;#21382;#20102;#21508;#31181;#21508;#26679;#30340;#25913;#36827;#12290;#28982;#32780;#65292;#23613;#31649;#22806;#31185;#25163;#26415;#25216;#26415;#26377;#20102;#36827;#27493;#65292;#20294;#30001;#20110;#30740;#31350;#20026;#22238;#39038;#24615;#12289;#26679;#26412;#37327;#23567;#21644;#26368;#37325;#35201;#30340;#38543;#35775;#26102;#38388;#30701;#65292;#30740;#31350;#32467;#26524;#19981;#23613;#20154;#24847;#12290;#26412;#32508;#36848;#26088;#22312;#28145;#24230;#25506;#35752;#32463;#24041;#33180;#32541;#32447;#22266;#23450;#20154;#24037;#26230;#29366;#20307;#26893;#20837;#26415;#30340;#36827;#23637;#65292;#24182;#23545;#20170;#21518;#30340;#21457;#23637;#26041;#21521;#25552;#20986;#24314;#35758;#12290.

Purpose Determining which factors influence idiopathic macular hole (MH) size is important because it is a major prognostic indicator of treatment success. Foveal pit morphologic features are highly symmetrical within individuals and may influence idiopathic MH size. Using a series of patients with unilateral idiopathic MHs, we examined the foveal floor size of the fellow eye to evaluate its relationship with idiopathic MH size and postoperative outcomes. Design Retrospective observational study. Participants Two hundred forty-one participants with a unilateral idiopathic MH treated with surgery and a fellow eye with no ocular pathologic features. Methods Both eyes underwent spectral-domain (SD) OCT imaging at the time of surgery. Minimum linear diameter (MLD) and base diameter (BD) defined idiopathic MH size. Foveal floor width (FFW) and minimal foveal thickness defined foveal pit morphologic features of the fellow eye. Main Outcome Measures Baseline characteristics, SD OCT measurements, and preoperative variables were compared to determine their relationship with idiopathic MH size and postoperative visual acuity (VA) in logarithm of the minimum angle of resolution units. Results Foveal floor width was correlated with MLD (r = 0.36; P ≤ 0.001) and BD (r = 0.30; P ≤ 0.001), but not postoperative VA. Minimum linear diameter correlated with preoperative VA (r = 0.49; P ≤ 0.0001) and postoperative VA (r = 0.54; P ≤ 0.0001). A 2-stage regression model was developed to predict postoperative VA (r2 = 0.28): preoperative VA (β = 0.36; P = 0.002) explained 13% of variability and MLD (β = 0.29; P = 0.002), and idiopathic MH duration (β = 0.23; P = 0.004) explained a further 16%. Conclusions Foveal floor width of the fellow eye in patients with a unilateral idiopathic MH was correlated significantly with idiopathic MH size and may explain some of the variability in idiopathic MH size observed between individuals. However, FFW could not predict postoperative vision.

[No abstract]

Vitreoretinal (VR) surgeons have high rates of spinal pain. The aim of this study was to investigate if VR surgeons adopt more complex postures in indirect ophthalmoscopy procedures compared with procedures involving the slit-lamp or operating microscope.Postures of the neck, back, and overall spine were measured by inclinometers on 13 VR surgeons. Each doctor was measured during 3 indirect examinations and 3 slit-lamp examinations (SLE), and then during 1 operating microscope procedure (phacoemulsification/vitrectomy) and 1 indirect procedure (indirect laser or cryotherapy/buckle).The average degree of flexion of neck/back/overall spine was significantly higher in indirect examinations compared with SLE (p0.01). SLE involved mainly neutral flexion, whereas indirect examinations involved significant time in moderate flexion of the neck and overall spine (42.2% and 76.2%, respectively), lateral bending of the back and overall spine (62.5% and 38%), and rotation of the neck and overall spine (76.6% and 32.1%). For indirect procedures, the neck was in moderate flexion and rotation approximately half of the time, and the overall spine was moderately flexed in75% of the time.Based on biomechanical concepts, VR surgeons are at risk of developing spinal pain because they adopt postures that are described as ergonomically unacceptable.

To provide data on visual acuity (VA) outcomes and prognostic factors of microincision (23-gauge) vitrectomy surgery (MIVS) for retained lens fragments after complicated cataract surgery.Retrospective, interventional case series from 2012 to 2017.Precataract surgery and intraoperative (vitrectomy) parameters, postvitrectomy complications, and best-corrected visual acuities (BCVAs) were identified. Vitrectomy was performed as early as corneal clarity permitted. Univariate and multivariate logistic regression were used to characterize factors associated with achieving VA better than 20/40, or worse than 20/200 at 6 months.This study included 291 consecutive eyes (291 patients). LogMAR BCVA improved from 0.73 ± 0.70 before cataract surgery to 0.46 ± 0.63 (P.001) after vitrectomy. The previtrectomy VA was 1.43 ± 0.79. At 6 months, 183 (62.9%) and 45 patients (15.5%) achieved BCVAs better than 20/40 and worse than 20/200, respectively. Most frequent complications were de novo ocular hypertension (29 eyes, 10%) and transient cystoid macular edema (25 eyes, 8.6%). Postvitrectomy retinal detachment occurred in 9 eyes (3.1%). Final VA of 20/40 or better was independently associated only with better precataract surgery VA, age75 years, absence of preexisting diabetic macular edema (DME) or postvitrectomy persistent cystoid macular edema (P.05). Only poorer precataract surgery VA, delaying vitrectomy to later than 2 weeks, and final aphakic status were independently predictive of 20/200 or worse VA (P.05).Contemporary VA outcomes of 23-gauge vitrectomy for retained lens fragments are comparable with that of prior predominantly non-MIVS cohorts, but fall short of benchmarks for uncomplicated cataract surgery. IOL type or timing of placement do not impact final VA.

Background/aimsThe reason for visual impairment in patients with nanophthalmos and posterior microphthalmos is not completely understood. Therefore, this study aims to investigate foveal structure, and the impact of demographic, clinical and imaging parameters on best-corrected visual acuity (BCVA) in these conditions.MethodsSixty-two eyes of 33 patients with nanophthalmos (n=40) or posterior microphthalmos (n=22), and 114 eyes of healthy controls with high-resolution retinal imaging including spectral-domain or swept-source optical coherence tomography images were included in this cross-sectional case–control study. Foveal retinal layer thickness was determined by two independent readers. A mixed-effect model was used to perform structure–function correlations and predict the BCVA based on subject-specific variables.ResultsMost patients (28/33) had altered foveal structure associated with loss of foveal avascular zone and impaired BCVA. However, widening of outer nuclear layer, lengthening of photoreceptor outer segments, normal distribution of macular pigment and presence of Henle fibres were consistently found. Apart from the presence of choroidal effusion, which had significant impact on BCVA, the features age, refractive error, axial length and retinal layer thickness at the foveal centre explained 61.7% of the variability of BCVA.ConclusionThis study demonstrates that choroidal effusion, age, refractive error, axial length and retinal layer thickness are responsible for the majority of interindividual variability of BCVA as well as the morphological foveal heterogeneity in patients with nanophthalmos or posterior microphthalmos. This might give further insights into the physiology of foveal development and the process of emmetropisation, and support clinicians in the assessment of these disease entities.

PurposeThe purpose of the study was to investigate the role of ethnicity on idiopathic macular holes (IMH) structure and surgical outcome. This was a retrospective review.Patients and methodsConsecutive patients undergoing primary IMH surgery at two surgical sites of Moorfields Eye Hospital (London, UK) between April 2012 and June 2013. The main outcome measure was post surgical anatomical closure of IMH.ResultsTwo hundred and twenty two primary IMH surgeries were undertaken. A standard procedure including pars plana vitrectomy, internal limiting membrane peeling, and gas tamponade was undertaken for all cases. 61.3% of patients were Caucasian, 21.2% were South Asian, and 16% were Afro-Caribbean. The mean minimum linear diameter (MLD) for our cohort was 434.6 mcm. Mean MLD was 395.3 mcm in Caucasian patients, 490.0 mcm in South Asians (P=0.006), and 491.4 mcm in Afro-Caribbeans (P=0.007). Regression analysis demonstrated that MLD and Afro-Caribbean ethnicity were independent significant risk factors for surgical failure (OR: 1.01, P0.001 and OR: 5.73, P=0.008, respectively).ConclusionSouth Asian and Afro-Caribbean patients present with larger IMH than Caucasians. In addition to IMH diameter, Afro-Caribbean ethnicity is an independent risk factor for surgical failure.

Reported 5-year survival rates in patients undergoing vitreous surgery for proliferative diabetic retinopathy (PDR) range from 68-95%. Studies relating survival rates to medical baseline characteristics predate the millennium. This study aimed to update data on life expectancy of patients undergoing vitrectomy for PDR and identify baseline factors which may influence survival.A retrospective cohort study of consecutive patients who underwent their first pars-plana vitrectomy for PDR between April 2004 and May 2005 was performed. Survival status on 1 May 2012 was the primary endpoint. The Kaplan-Meier life table method was used to determine survival rates. Univariate and multiple variable Cox proportional hazards regressions were used to identify risk factors for mortality.A total of 148 patients were included in the study, with a mean age of 54 years (range 20-80 years) at time of surgery. The 3-, 5- and 7-year survival rates were 94%, 86% and 77%, respectively (95% confidence interval, CI, 88-97%, 79-91% and 68-84%, respectively). Renal failure was the most common cause of death. The presence of limb ulcers at baseline was the most important prognostic indicator for mortality, with a hazard ratio of 3.13 (95% CI 1.46-6.71, p = 0.003) and a survival rate at 5 years reduced to 79%.The 5-year survival rate remains comparable to those reported 20 years ago despite a lowering in threshold for vitrectomy and increased health awareness. Limb ulcers are strongly associated with increasing mortality. Clinicians should remain mindful of the systemic associations of diabetes particularly in advanced retinal disease.

To describe the widefield spectral-domain optical coherence tomography features of peripheral round retinal holes, with or without associated retinal detachment (RD).Retrospective, observational study of 28 eyes with peripheral round retinal holes, with and without RD. Patients underwent imaging with a widefield 50-degree spectral-domain optical coherence tomography (Heidelberg Engineering, Germany) and Optos ultra-widefield imaging systems (Optos, United Kingdom).Vitreous attachment at the site of the retinal hole was detected in 27/28 (96.4%) cases. Cases were split into three groups: RHs with RD (n = 12); RHs with subretinal fluid (n = 5), and flat RHs (n = 11), with minimal or no subretinal fluid. 91.6% retinal holes associated with subretinal fluid or RD had vitreous attachment at the site of the hole. Eighty percent had vitreous attachment at both edges of the retinal hole, in a U-shape configuration, which appeared to exert traction. By contrast, flat retinal holes had visible vitreous attachment only at one edge of the retinal hole in 45.4%.Vitreous attachment was commonly seen at the site of round retinal holes. Vitreous attachment at both edges of the retinal hole in a U-shape configuration was more commonly seen at holes associated with subretinal fluid or RD.

Visual impairment is a growing problem worldwide.1 By 2040, it is estimated that 288 million patients will have some forms of AMD,2 119 million with glaucoma cases,3 and 422 millions with DR.4 With ageing populations globally, most eye health services will struggle to manage these eye diseases with existing manpower and infrastructure, and face significant financial constraints.5 In this setting, new models of care with digital health technologies and platforms are urgently needed.5 Conventionally, eye care service delivery can be conducted via routine, mobile and teleophthalmology settings. With the advancement in technology and telecommunication networks, numerous novel digital health solutions and service models can streamline and automate critical aspects of the screening and monitoring processes,6 including secure telemedicine platforms that can be coupled with automated algorithms using artificial intelligence and big data analytics.6 These measures not only help screen and triage patients with new eye diseases, but can also monitor stable patients who do not require management in tertiary eye care settings. Telemedicine can be broadly divided into two types—synchronous and asynchronous models. The synchronous model usually requires good internet connectivity that enables real-time consultations between patients and physicians via a telemedicine platform. This model is useful for emergency rooms consultations in rural hospital settings where ophthalmology services are limited. Local emergency physicians could use telemedicine platforms to present their patients’ history and ocular examination, enabling ophthalmologists or specialists to help triage the urgency of referrals or …

Purpose: Our aim was to evaluate the impact of intravitreal ranibizumab pretreatment on the outcome of vitrectomy surgery for advanced proliferative diabetic retinopathy. The objective was to determine the feasibility of a subsequent definitive trial and estimate the effect size and variability of the outcome measure. Patients and methods: We performed a pilot randomised double-masked single-centre clinical trial in 30 participants with tractional retinal detachment associated with proliferative diabetic retinopathy. Seven days prior to vitrectomy surgery, participants were randomly allocated to receive either intravitreal ranibizumab (Lucentis, Novartis Pharmaceuticals UK Ltd, Frimley, UK) or subconjunctival saline (control). The primary outcome was best-corrected visual acuity 12 weeks following surgery.Results: At 12 weeks, the mean (SD) visual acuity was 46.7 (25) ETDRS letters in the control group and 52.6 (21) letters in the ranibizumab group. Mean visual acuity improved by 14 (31) letters in the control group and by 24 (27) letters in the ranibizumab group. We found no difference in the progression of tractional retinal detachment prior to surgery, the duration of surgery, or its technical difficulty. Vitreous cavity haemorrhage persisted at 12 weeks in two of the control group but none of the ranibizumab group.Conclusion: Ranibizumab pretreatment may improve the outcome of vitrectomy surgery for advanced proliferative diabetic retinopathy by reducing the extent of post-operative vitreous cavity haemorrhage. However, the effect size appears to be modest; we calculate that a definitive study to establish a minimally important difference of 5.9 letters at a significance level of P

Purpose: To describe small hyperreflective areas using spectral-domain optical coherence tomography (SD-OCT) imaging in eyes that have had silicone oil tamponade. Methods: Retrospective case series of 11 eyes of 11 patients. The authors retrospectively identified patients who underwent vitrectomy and silicone oil tamponade secondary to a rhegmatogenous retinal detachment (nine patients), panuveitis with retinal necrosis (one patient), or recurrent full-thickness macular hole surgery (one patient) who had manifestations of silicone oil emulsion on SD-OCT imaging. Patients were monitored during the postoperative period by clinical examination and using SD-OCT. A model eye in which emulsified silicone oil had been injected in the anterior chamber was used to obtain anterior segment SD-OCT images for comparison. Results: The mean age of our patients was 50 years (range, 39–76 years). In eight eyes, the SD-OCT examination was carried out after silicone oil removal, and in three eyes, the SD-OCT examination was carried out with the oil in situ. Of the nine eyes treated for rhegmatogenous retinal detachment, five had a relieving retinectomy for advanced anterior proliferative vitreoretinopathy or for traumatic retinal incarceration (one eye). The eye treated for full-thickness macular hole had a vitrectomy, internal limiting membrane peel, and silicone oil injection for recurrent macular hole. Ten eyes showed hyperreflective, spherical, tiny droplets using SD-OCT imaging. These were thought to represent silicone oil droplets intraretinally or underneath epiretinal membranes, and one eye showed hyperreflective areas subretinally (retina detached). One additional patient was found to have tiny intravitreal silicone oil droplets after silicone oil removal. Similarly, the silicone oil appeared as multiple hyperreflective spherical droplets as detected by SD-OCT. Anterior segment studies of silicone oil emulsification in the experimental model revealed a similar appearance to that seen with in vivo SD-OCT imaging. Conclusion: The authors have found small hyperreflective areas intraretinally, subretinally, and underneath epiretinal membranes on SD-OCT in eyes that have had silicone oil tamponade for a variety of indications. The authors have seen a similar appearance when silicone oil emulsification is examined in vivo. The authors conclude that the hyperreflective areas are likely (but not certain) to be very small bubbles of emulsified silicone. Further studies are required to determine the incidence, clinicopathologic, and functional significance of probable silicone oil emulsification and deposition within the retinal layers.

To examine the natural history of vitreomacular traction syndrome (VMTS) in the absence of other ocular comorbidities.Retrospective clinical case series.A total of 183 eyes of 159 patients diagnosed with VMTS with no other ocular comorbidity.Patients with VMTS were identified from an OCT database at Moorfields Eye Hospital, London. Sequential OCT scans and patient notes were reviewed over a minimum period of 6 months. Data collected included patient demographics, best-corrected visual acuity, and OCT features of vitreomacular adhesion. Contingency tests and binary logistic modeling were used to identify baseline predictors of stability and progression.The rates of spontaneous resolution (defined by release of traction), progression to full-thickness macular hole, and surgical intervention were analyzed.Presenting visual acuity was 0.3±0.3 logMAR units. The mean length of follow-up was 17.4±12.1 months. During this period, VMTS persisted in 60% and resolved in 20% (occurring on average at 15 months). Of the remainder, 12% developed a macular hole and 8% elected to proceed with surgery for symptoms. Focal adhesion1500 μm was present in 87%. A premacular membrane with macular pucker (PMM) was present in 20%. With persistent VMTS, vision and central foveal thickness remained unchanged. The relative risk of resolution increased in those cases with better presenting visual acuities, lesser foveal thicknesses, and no associated PMMs; vision significantly improved in those cases with resolution.VMTS persists in the majority of patients but despite this, visual acuities did not deteriorate significantly over the study period unless patients developed a full-thickness macular hole or required surgical intervention for symptoms. Resolution spontaneously occurred in 20%, with an improvement in vision.

PurposeTo correlate the frequency and extent of simultaneous inadvertent internal limiting membrane (ILM) peeling during idiopathic epiretinal membrane (ERM) removal with characteristics of ERM adherence demonstrated on pre-operative spectral domain optical coherence tomography (SD-OCT).Patients and methodsThis is a prospective, observational, case series of patients undergoing pars plana vitrectomy for idiopathic ERM. Inner retina-ERM adhesion was categorized as focal, broad or complete in five anatomic locations at macular area based on preoperative SD-OCT findings. The extent of spontaneous ILM peeling was quantified on a scale 0-100% in each of the aforementioned anatomic locations by the operating surgeons who were masked to the OCT characteristics. All operations were recorded with a high definition recording system and the area of simultaneous ILM peel was quantified by a second masked observer. The final extent of spontaneous ILM peel was calculated as the average of the two scores.ResultsThirty consecutive subjects who underwent surgery for idiopathic ERM were included in the study. Evidence of simultaneous ILM peeling was identified in 80.3% of individuals. With regards to the type of ERM-macula adhesion, inadvertent ILM peel was observed in 70% of the patients who pre-operatively showed complete adhesion, in 43% with broad adhesion and in only 21% with focal adhesion (P

Purpose To identify the prognostic factors affecting the surgical outcomes in patients with vitreomacular traction syndrome undergoing pars plana vitrectomy. Methods This was a retrospective clinical study of 67 eyes of 67 patients with vitreomacular traction syndrome who underwent pars plana vitrectomy. Demographic, clinical, and optical coherence tomography (OCT) characteristics were collected and analyzed. Univariate and multivariate linear regression analysis were used to examine the effect of parameters on change in best-corrected visual acuity (BCVA). Results At a mean follow-up period of 15.9±12 months (mean±SD), the BCVA improved from 0.7±0.3 LogMAR (mean±SD) to 0.5±0.3. Seven patients developed full-thickness macular hole intraoperatively and tamponade (air, 20% SF6 or 12% C3F8) was used in 41 patients. Retinal breaks were identified intraoperatively in four patients. Regression analysis demonstrated that the preoperative BCVA was the only parameter affecting the postoperative visual outcome. Conclusion In the present study, the preoperative BCVA plays a predictive role in the surgical outcome of patients with VMT undergoing pars plana vitrectomy. No other preoperative OCT characteristics demonstrated prognostic potential. Further prospective studies are needed in order to examine the role of several factors that could potentially facilitate preoperative patient counselling.

OBJECTIVE: This was a pilot randomised controlled trial (RCT) to investigate the effect of post-operative face-down positioning on the outcome of macular hole surgery and to inform the design of a larger definitive study. METHODS: In all, 30 phakic eyes of 30 subjects with idiopathic full-thickness macular holes underwent vitrectomy with dye-assisted peeling of the ILM and 14% perfluoropropane gas. Subjects were randomly allocated to posture face down for 10 days (posturing group) or to avoid a face-up position only (non-posturing group). The primary outcome was anatomical hole closure. RESULTS: Macular holes closed in 14 of 15 eyes (93.3%; 95% confidence interval (CI) 68-100%) in the posturing group and in 9 of 15 (60%; 95% CI 32-84%) in the non-posturing group. In a subgroup analysis of outcome according to macular hole size, all holes smaller than 400 μm closed regardless of posturing (100%). In contrast, holes larger than 400 μm closed in 10 of 11 eyes (91%; 95% CI 58-99%) in the posturing group and in only 4 of 10 eyes (40%; 95% CI 12-74%) in the non-posturing group (Fisher's exact test P=0.02). CONCLUSION: Post-operative face-down positioning may improve the likelihood of macular hole closure, particularly for holes larger than 400 μm. These results support the case for a RCT.

Devise simplified formulae, using preoperative clinical data, to give risk estimates of (1) failure and (2) proliferative vitreoretinpathy (PVR) following primary retinal detachment repair by vitrectomy.641 patients were analysed as part of an RCT investigating use of 5-fluorouracil and low-molecular-weight heparin. Treatment status had no effect on success rates and did not therefore form part of the analyses. Preoperative risk factors for surgical failure and for PVR within 6 months of retinal detachment surgery were identified, and a multiple variable logistic regression model developed. Further analyses were performed to devise a simple points system to produce risk estimates of failure.Three risk factors were related to failure-previous lens extraction (p=0.046), grade C PVR (p=0.039) and extent of detachment (p0.001). Three risk factors were also related to failure due to PVR-vitreous haemorrhage (p=0.088), grade C PVR (p=0.044) and extent of detachment (p0.001). There was good agreement between risk estimates produced by the points system and those calculated directly using a multivariate regression model. The points-system model gave an area under the receiver operating characteristic curve of 0.658. The receiver operating characteristic curve for the PVR model gave an area under the curve of 0.8399 suggesting greater diagnostic value.A simple points system may be used as a clinical guide to identify patients at higher risk of failure following retinal detachment repair by vitrectomy. This may help clinicians select appropriate surgical approaches and stratify cases in research and surgical training.

Conventional silicone oil provides suboptimal support of the inferior retina. In this study we evaluated the efficacy of Oxane HD in the management of complex retinal detachments involving lower quadrants of the retina. A prospective, interventional, comparative study. Eighteen patients were recruited. Treatment outcomes were compared with a historical control group of 14 patients. Patients with grade C3 PVR or greater and inferior retinal breaks, recurrent inferior retinal detachments (with or without PVR) and giant retinal tears were included. In those patients who re-detached under heavy silicone oil (n = 4), retro-oil epiretinal membranes (ERMs) were obtained at the time of subsequent surgery to analyse the immunopathological response to oxane HD. Immunohistochemistry was used to detect glia, retinal pigment epithelium cells (RPE), macrophages, T lymphocytes, or neural elements in the tissue using well-characterised monoclonal antibodies. Retinal attachment of the posterior pole following removal of silicone oil was achieved in 66.6% of the treatment group (n = 12) and 64.3% of controls (n = 9) (p = 1.0). Post-operative PVR developed in five patients in the treatment group (27.8%) and five control patients (35.8%). Following removal of silicone oil, residual oil was observed in 27.8% of the treatment group and 7.1% of controls. Median visual acuity, 3 months following removal of silicone oil, was 2.0 (IQR 0.9–2.0) in the treatment group and 1.0 (IQR 0.6–1.8) in the control group. Complications in the treatment group included, hypotony (n = 3), uveitis (n = 2), glaucoma (n = 1). All ERMs analysed demonstrated microscopic appearances typical of PVR. The membranes were fibrocellular in nature, contained RPE and glial cells, and variable amounts of intracellular and extracellular pigment. In addition, all had a dense infiltrate of vacuolated (presumed oil-filled) macrophages. We failed to observe an advantage following the use of Oxane HD in the treatment of inferior retinal detachments. Moreover, Oxane HD was difficult to remove and was associated with a higher incidence of complications.

To compare post-operative pain following 25-gauge (25G) and 20-gauge (20G) vitrectomy in the first week following surgery.The study was a pilot randomised controlled trial with patients masked to the treatment allocation. Post-operative pain was assessed using both a visual scale and verbal pain scores for 1 week following surgery. Additional data collected included intraocular pressure (IOP), time taken to perform the surgical procedure, per-operative and post-operative complications, and dropout rates.Forty patients were recruited for the study: 21 randomised to 20G vitrectomy and 19 to 25G. In the first 12 h following surgery, presence of significant post-operative pain (defined as1 cm on a visual analogue scale) was similar in both 20G (50%) and 25G (53%) patients. In the first week following surgery, 38 of the 527 scores (7.2%) were1 (median 2.1, IQR 1.3-3) cm; however, there was evidence that "significant pain" was experienced more commonly in the 20G group. There was no statistical difference in the time taken to complete the surgical procedure, although in the 25G group the time from first incision to the start of vitrectomy was significantly shorter (p = 0.043) and in the 20G group the time taken to complete the vitrectomy was less (p = 0.047). Post-operative hypotony (IOP6 mmHg) was observed in 25% of patients in the 25G group. No patients required additional surgery for hypotony.There was evidence that 25G resulted in less patient discomfort. However, pain was not a prominent feature in either group. We failed to find a significant advantage in 25G for patients or surgeons.

Aims: To carry out a histopathological analysis of retinal specimens of patients undergoing translocation surgery for age-related macular degeneration (ARMD). Methods: A histopathological analysis, using confocal microscopy, was performed on six retinal specimens. Results were compared with those from two further retinal specimens, collected during RPE transplantation, to control for the effects of vitrectomy and ARMD. In addition, a third control specimen from a cadaver with no history of ophthalmic disease was also analysed. Results: In the translocation specimens, rods and cones were relatively well preserved but showed reduced density and outer segment length. In four specimens, there were focal areas of rod opsin redistribution to the inner segment, but this was not observed in the controls. Staining with calbindin was decreased in cones compared with controls but normal in horizontal and amacrine cells. Rod bipolar cells were mildly disorganised, and in one there was evidence of neurite sprouting. Glial fibrillar acidic protein was raised in both translocation and transplantation retinae but not in the cadaver control. Conclusions: In this study, there was little evidence of cellular injury following iatrogenic detachment; however, the rate of PVR following translocation surgery infers that cellular events set in motion may continue despite early reattachment.

To study the preoperative characteristics, complications and outcomes of vitrectomy for proliferative diabetic retinopathy and to identify any factors that may predict visual outcome.Prospective study of 174 consecutive vitrectomies in 148 patients, with a minimum follow-up of 4 months.41 (27.7%) patients had a vision of6/60 in their better eye at presentation. Posterior retinal breaks occurred in 47 (27.0%) eyes. Postoperative complications included vitreous cavity haemorrhage in 37 (22.0%) eyes, retinal detachment in five eyes (3.0%), and rubeotic glaucoma in five eyes (3.0%). 124 (74.7%) eyes improved by at least 0.3 LogMAR units, and 15 (9.0%) worsened by at least 0.3 LogMAR units. 119 (71.7%) eyes had a visual acuity of 6/60 or better, and 27 (16.3%) were counting fingers or worse. Only 16 (11.1%) patients had a vision of6/60 in both eyes at latest follow-up. Preoperative vision in both the operated eye and the contralateral eye, macular detachment, and long-acting intraocular tamponade were independent predictors of poor postoperative vision, but this model accounted for only a small proportion of the observed variation in outcomes.Major complications are rare after vitrectomy for proliferative diabetic retinopathy, and70% of eyes will regain vision of 6/60 or better. Visual outcomes remain unpredictable.

Objective To determine the efficacy of a combination of 5-fluorouracil (5FU) and low-molecular-weight heparin (LMWH) in the treatment of unselected rhegmatogenous retinal detachment (RRD) undergoing primary vitrectomy. Design Double-masked, prospective, randomized, placebo-controlled clinical trial. Participants Six hundred forty-one patients presenting with primary RRD were recruited from 2 specialized vitreoretinal units—Moorfields Eye Hospital, London (n = 553) and St. Pauls Eye Unit, Liverpool (n = 88). Intervention All patients underwent primary vitrectomy and gas endotamponade. Adjuvant therapy in the treatment group consisted of 5 IU/ml LMWH and 200 μg/ml 5FU added to the perioperative infusion fluid. Main Outcome Measures The primary outcome measure was retinal reattachment after primary vitrectomy without any reoperations at 6 months. Secondary outcome measures recorded at 6 months were the occurrence and grade of proliferative vitreoretinopathy (PVR), best-corrected visual acuity in logarithm of the minimum angle of resolution, intraocular pressure (mmHg), corneal clarity, and complications. Results The overall primary success rate was 84.4%; in the treatment group, the primary success rate was 82.3% compared with 86.8% in the placebo group ( P = 0.12). At 6 months, the final complete anatomical reattachment rate was 97.9% in both treatment and placebo groups. The number of patients who failed due to the development of PVR was not statistically significant, 23 in the treatment group (7.0%) and 14 in the placebo group (4.9%) ( P = 0.309). There was no significant difference in the mean visual acuity at 6 months in the placebo group (0.48) versus the treatment group (0.53; P = 0.072). The visual acuity at 6 months of patients presenting with a macula-sparing retinal detachment was significantly worse in the treatment group ( P = 0.0091). There was no significant difference between the 2 groups in patients who presented with a macula involving retinal detachment ( P = 0.896). Conclusions Primary vitrectomy has a high anatomic and visual success rate for RRD. Adjuvant therapy with 5FU and LMWH does not improve the anatomic or visual success rate of unselected primary retinal detachments undergoing vitrectomy. After adjuvant therapy, a worse visual outcome was observed in patients presenting with macula-sparing retinal detachments. A combination of 5FU and LMWH should not be used routinely for primary RRD surgery.

Aims: To characterise the distribution of silicone oil in ocular tissues in globes enucleated after complicated retinal detachment, and to document the distribution and nature of any associated inflammatory response. Method: 9 enucleated globes that had previously undergone retinal detachment surgery with silicone oil and 7 control globes that had undergone enucleation after retinal detachment surgery (n = 2) or ocular trauma (n = 5) were studied. Sections were histologically examined using light microscopy to document the distribution of silicone oil in ocular tissues. Immunohistochemical analysis was carried out using the ABC technique and a panel of monoclonal and polyclonal antibodies. Electron microscopy was undertaken to observe the penetration of silicone oil in the trabecular meshwork of the anterior chamber drainage angle. Results: Silicone oil was distributed throughout the globes—notably in the iris, ciliary body, retina, trabecular meshwork and epiretinal membranes. Focal areas of intraretinal silicone were associated with disorganised retinal architecture, retinectomy sites or subretinal oil. The distribution of macrophages was closely related to the distribution of silicone oil. T and B lymphocytes were not associated with silicone oil unless additional pathology was also present—for example, cyclitic membrane or uveitis. One of the nine eyes had silicone oil present in the optic nerve. In the control globes, the inflammatory response was mediated primarily by macrophages and T lymphocytes, and was less marked than that observed in the silicone oil globes. Conclusion: This study shows that silicone oil may be sequestered in varied ocular tissues and is associated with localised inflammation mediated by macrophages.

Aims: To determine the inflammatory response in retina and epiretinal membranes after intraocular silicone oil tamponade. Methods: 14 proliferative vitreoretinopathy (PVR) epiretinal membranes, 33 retro-oil epiretinal membranes, 19 retinectomies, 14 retro-oil retinectomies and 37 idiopathic epiretinal membranes (controls) underwent immunohistochemical analysis using the avidin–biotin complex technique and a panel of monoclonal and polyclonal antibodies. The number of positive cells counted in five 0.5 mm diameter fields of immunohistochemical sections was graded on a score of 1–4. Results: Macrophage cell counts were significantly greater in membranes with a history of exposure to silicone oil (p

PurposeTo develop and validate a classification system for focal vitreomacular traction (VMT) with and without macular hole based on spectral domain optical coherence tomography (SD-OCT), intended to aid in decision-making and prognostication.MethodsA panel of retinal specialists convened to develop this system. A literature review followed by discussion on a wide range of cases formed the basis for the proposed classification. Key features on OCT were identified and analysed for their utility in clinical practice. A final classification was devised based on two sequential, independent validation exercises to improve interobserver variability.ResultsThis classification tool pertains to idiopathic focal VMT assessed by a horizontal line scan using SD-OCT. The system uses width (W), interface features (I), foveal shape (S), retinal pigment epithelial changes (P), elevation of vitreous attachment (E), and inner and outer retinal changes (R) to give the acronym WISPERR. Each category is scored hierarchically. Results from the second independent validation exercise indicated a high level of agreement between graders: intraclass correlation ranged from 0.84 to 0.99 for continuous variables and Fleiss' kappa values ranged from 0.76 to 0.95 for categorical variables.ConclusionsWe present an OCT-based classification system for focal VMT that allows anatomical detail to be scrutinised and scored qualitatively and quantitatively using a simple, pragmatic algorithm, which may be of value in clinical practice as well as in future research studies.

To determine the outcome of surgery in patients who presented with posterior segment intraocular foreign bodies (IOFBs) and to identify factors associated with poor visual outcome. To assess whether improvement in vitreo-retinal surgical techniques over the past 17 years has resulted in an improvement in the outcome of these patients. A retrospective cohort study carried out at Moorfields Eye Hospital, London. Patients who underwent a primary surgical repair and removal of a posterior segment IOFB were identified using a hospital database. Of the 140 patients identified, 114 (81%) were included in the study. Data on age, activity at time of injury, presenting clinical features, surgical techniques, complications and final visual outcome were recorded and analyzed. The mean age at time of injury was 34.6±12.4 years. All patients were male. The majority of IOFBs were metal (83%). Hammering and chiselling were the most common activities at the time of injury (66%). Fifty-three percent of patients presented with a visual acuity of 6/36 or better. Primary closure was achieved in a median of 1 day (interquartile range 1–3 days) following injury. A final visual outcome of 6/60 or worse was documented in 31%. Presentation with a relative afferent pupillary defect (P

Importance Panretinal photocoagulation (PRP) for proliferative diabetic retinopathy (PDR) may lead to peripheral field loss that prevents driving. Anti–vascular endothelial growth factor agents are proposed as treatments for PDR that spare peripheral vision. If multispot lasers cause less visual field loss, continuing to perform PRP may be justified. Objective To assess the effect of bilateral multispot laser PRP on retinal sensitivity and driving visual fields in PDR. Design, Setting, and Participants This prospective nonrandomized interventional cohort analysis performed at a tertiary referral center included 43 laser-naive patients with PDR that required bilateral PRP. Participants were recruited from June 27, 2012, to October 14, 2013. At baseline and 6-month follow-up, patients underwent detailed static and kinetic perimetry, microperimetry, optical coherence tomography, wide-field color fundus photography, and fluorescein angiography. Quantitative change in retinal sensitivity was assessed by comparing the mean global retinal sensitivity before and after laser treatment and by comparing the modeled hill of vision by deriving a volumetric measure. Final follow-up was completed on May 21, 2014. Interventions Multispot laser treatment was applied using standard parameters, until neovascularization regressed or complete retinal coverage was achieved. Main Outcomes and Measures Participants who passed the Esterman binocular visual field test for driving in the United Kingdom (at least 120° horizontal field with no significant defects within the central 20°) and full-field and macular retinal sensitivity. Results Of the 43 patients (17 men; 26 women; mean [SD] age, 46.6 [13.3] years), 38 (88%) completed the study. Before treatment, 41 of 43 patients (95%) passed the Esterman visual field test for driving; after completion of laser treatment, 35 of 38 patients (92%) passed. The mean (SD) change in retinal sensitivity on static perimetry was −1.4 (3.7) (95% CI, −2.7 to −0.1) dB OD and −2.4 (2.9) (95% CI, −3.4 to −1.4) dB OS. Mean (SD) 4° macular sensitivity decreased by 3.0 (5.2) dB OD and 2.6 (5.4) dB OS. Conclusions and Relevance This prospective study investigating the effects of multispot laser PRP on retinal sensitivity demonstrates a high likelihood of retaining eligibility to drive based on adequate visual field. A mild loss of retinal sensitivity was detected at 6 months after completion of laser treatment. Further change to visual fields may have occurred with longer follow-up. This study provides information that might be used to counsel patients requiring PRP and informs the debate regarding the role of anti–vascular endothelial growth factor therapy in patients with PDR who might otherwise receive laser treatment.

To identify preoperative features associated with surgical failure following vitrectomy using data collected in a large, prospective randomised controlled trial. Outcomes of patients who redetached were then examined in more detail.615 patients were analysed as part of an randomised controlled trial investigating the use of 5-fluorouracil and low-molecular-weight heparin. Treatment status had no effect on success rates and did not therefore form part of the analyses. Failure was defined as retinal redetachment within 6 months of primary vitrectomy. Univariate logistic regression analysis was used to assess association between failure and putative risk factors (age, pathological myopia, intraocular pressure, vitreous haemorrhage, previous lens extraction, uveitis, number of retinal quadrants detached, number and distribution of retinal breaks, and grade C proliferative vitreoretinopathy (PVR)). Additional characteristics of patients were then elucidated including number of operations required to achieve retinal reattachment, surgical techniques used and final logMAR visual acuity.96 patients (15.6%) redetached following surgery, and 37 failed due to PVR. Surgical failure was associated with number of retinal quadrants detached (OR per increase, 1.69 (1.33 to 2.15) p0.001) and grade C PVR (OR 3.98 (1.47 to 10.73) p=0.006). Inferior breaks were not identified as a risk factor (p=0.602). Repeat retinal detachment surgery showed a trend towards reduced visual acuity at 6 months providing PVR did not develop. PVR resulted in a significant deterioration in visual acuity.The extent of retinal detachment and preoperative PVR are risk factors for surgical failure following vitrectomy for primary retinal detachment. PVR was again confirmed as the major factor influencing visual outcomes.

Retinal detachment initiates a complex series of cellular and molecular changes. Because of the difficulty in obtaining retinal tissue from patients with retinal detachments, most investigations of the cellular changes following retinal detachment have been carried out on animal models. Animal experiments suggest that the cellular response to retinal detachment may be broadly described as; partial dedifferentiation of retinal pigment epithelium cells, proliferation and migration of retinal pigment epithelium cells into the subretinal space, degeneration of the photoreceptor outer segments and synaptic terminals, photoreceptor cell death, structural remodelling of second-order and third-order retinal neurons, proliferation of all non-neuronal cell types within the retina and Muller cell hypertrophy leading to glial scar formation. Each of these stages are considered in turn and related to findings in human proliferative vitreoretinopathy.

Retinal detachment initiates a complex series of cellular and molecular changes. Because of the difficulty in obtaining retinal tissue from patients with retinal detachments, most investigations of the cellular changes following retinal detachment have been carried out on animal models. Animal experiments suggest that the cellular response to retinal detachment may be broadly described as; partial dedifferentiation of retinal pigment epithelium cells, proliferation and migration of retinal pigment epithelium cells into the subretinal space, degeneration of the photoreceptor outer segments and synaptic terminals, photoreceptor cell death, structural remodelling of second-order and third-order retinal neurons, proliferation of all non-neuronal cell types within the retina and Muller cell hypertrophy leading to glial scar formation. Each of these stages are considered in turn and related to findings in human proliferative vitreoretinopathy.