E. Rodríguez de la Rúa

Proliferative vitreoretinopathy: risk factors and pathobiology

Proliferative vitreoretinopathy (PVR) is still a major cause of failure of retinal detachment surgery. Despite a dramatic increase in our pathobiologic knowledge of PVR during the last 10 years, little of this information has been used to modify the surgical management of the disease, and, thus, the anatomic and functional results are still unsatisfactory. Collaborative research involving clinicians and basic researchers must be encouraged. PVR must be considered a multifactorial disease caused by interaction of several cells and intra- and extraocular factors. Therefore, therapeutic options based on the inhibition of one factor or phenomenon may be regarded with scepticism. To prevent PVR, it is necessary to determine the factors involved in its development, and because of its relatively small prevalence, large, prospective, multicenter studies seem necessary. In addition, clinical research must not be underestimated. PVR affects both sides of the retina and the retina itself, a point to which little attention has been paid and that is critical for surgical results. Therefore, a new classification that provides information about clinical relevance, such as the evolutionary stages of the disease (biologic activity) and the degree of surgical difficulty (location of the fibrotic process), seems necessary.

Surgical outcomes for primary rhegmatogenous retinal detachments in phakic and pseudophakic patients: the Retina 1 Project—report 2

Aims: To compare anatomical and functional outcomes for 546 phakic and pseudophakic primary rhegmatogenous retinal detachments (RDs) treated by pars plana vitrectomy or scleral buckling. Methods: Prospective, non-randomised, interventional study in 15 centres in Spain and Portugal, with data from RDs consecutively treated from January 2005 to May 2007. Cases with preoperative proliferative vitreoretinopathy grade C-1 or higher and perforating trauma were excluded. Minimum follow-up was 3 months. Twenty-seven pre-, intra- and post-surgical variables for each patient were analysed. Multivariate analysis was carried out by logistic regression analysis with stepwise selection of variables. Results: Data from 546 patients were analysed. Global anatomical success was 94.7%. Logistic regression analysis showed that only the development of postoperative proliferative vitreoretinopathy was associated with a poor anatomical outcome. The poorest functional results were associated with macular involvement, extension of RD, previous RD surgery, time of evolution of RD, and age of patient. Hierarchical log-linear analysis showed no effect of the lens status (phakic versus pseudophakic) on the functional results. However, pars plana vitrectomy was most often performed in pseudophakic eyes and resulted in a worse final visual acuity (p<0.001). Conclusions: No differences in anatomical success between phakic and pseudophakic eyes were found in this series. Pars plana vitrectomy was most often performed in pseudophakic eyes and had a greater probability of a worse final visual acuity than scleral buckling.

Interaction between surgical procedure for repairing retinal detachment and clinical risk factors for proliferative vitreoretinopathy.

Purpose: To asses risk factors of proliferative vitreoretinopathy (PVR) and a model for predicting it. Methods: Observational, case-control. 335 patients with non-complicated retinal detachment (RD) were included: 134 developed PVR (Cases); 201 patients did not (Controls). Risk factors for PVR were identified by multivariate analysis. Influence of variables was assayed according to the surgical approach. By logistic regression analysis a model to predict the risk of developing PVR and odds ratio (OR) values for each clinical factor were estimated. Results: Risk was higher in patients > 70 years and with intraocular pressure lower than 14 (OR: 3.84; CI 95%: 2.04–7.30) and in retinal breaks larger than “1 clock hour” (OR: 2.54; CI: 1.28–5.05), extended retinal detachments (OR: 4.01; CI: 1.98–8.10) and reinterventions (OR: 1.55; CI: 1.14–9.22). Scleral surgery also was a risk factor (OR: 3.89; CI: 2.12–7.14) and aphakia/pseudophakia when scleral surgery is performed (OR: 3.33; CI: 1.54–7.22). A model to predict PVR was proposed with these results. Conclusions: Surgical approach modifies risk factors of PVR, and should be taken into account to improve the models for predicting it.

Factores clínicos de riesgo para el desarrollo de la vitreorretinopatía proliferante (VRP) postquirúrgica: Estudio prospectivo

espanolObjetivo: Identificar los factores de riesgo de VRP, la incidencia y el momento de aparicion de esta complicacion en una serie prospectiva de desprendimientos de retina regmatogenos (DR). Metodos: Se ha realizado un estudio multicentrico y prospectivo de 223 casos de DR. Se han incluido 83 variables referentes a caracteristicas preoperatorias, intraoperatorias y postquirurgicas. Se ha efectuado un analisis de regresion logistica. Resultados: De los 223 casos de DR, 22 desarrollaron una VRP (incidencia 9,9%, intervalo de confianza al 95%: 5,9-13,9). Se han detectado 4 factores con una «odds-ratio» superior a 1,0 (la existencia de un DR de 4 cuadrantes, el empleo de crioterapia, la afaquia o pseudofaquia y la necesidad de utilizar cerclaje). Ninguno de estos factores ha presentado una p EnglishPurpose: To identify clinical risk factors for development of postoperative PVR, to determine the incidence of this complication and its time of onset by a prospective multicentric study. Methods: A multicentric and prospective study of 223 patients with rhegmatogenous retinal detachment (RD) was conducted. Logistic regression analysis was used to identify risk factors for PVR among 83 variables related to preoperative, intraoperative and postoperative characteristics. Results: 22 out of 223 RD developed PVR (incidence 9.9%, confidence interval 95%: 5.9-13.9). After logistic regression analysis, four variables showed an odds ratio higher than 1.0 (RD affecting 4 quadrants, cryopexy, aphakia/pseudophakia and those RD in which an encircling band was implanted). None of these factors showed a «p» value lower than 0.05. Most of postoperative PVR (77.2%) appeared in the first month after surgery. Conclusions: This study establishes the incidence of PVR, and its time of onset, but it was not effective to identify clinical risk factors with a high level of confidence.

Acortamiento retinado: la forma más grave de la vitreorretinopatía proliferante (VRP)

espanolObjetivo: Identificar las caracteristicas clinicas de los pacientes que presentan una VRP con acortamiento retiniano no producido por membranas perirretinianas. Metodo: Estudio observacional, retrospectivo, de una cohorte de 110 pacientes intervenidos por VRP en 2000 y 2001. Durante la cirugia, tras eliminar las membranas epirretinianas y comprobar que no existian subretinianas, se inyecto un perfluorocarbono liquido. Los ojos en los que no se consiguio la reaplicacion retiniana se catalogaron como VRP intrarretiniana (grupo 1). Los casos en los que se consiguio una reaplicacion que permitio la aplicacion de endolaser sin realizar otras maniobras, constituyeron el grupo control (grupo 2). Se han comparado las caracteristicas clinicas preoperatorias de ambos grupos mediante el test de la chi- cuadrado. Resultados: 60 casos (54,5%, IC 95%: 40,5-68,5) se incluyeron en el grupo 1 y 24 casos (21,8%, IC 95%: 12,9-30,7) en el grupo 2. En los casos restantes, 26 (23,6%), la evaluacion presento dudas. En 9 (15%) de los 60 casos del grupo 1 fue necesario realizar una retinectomia. No hubo diferencias estadisticamente significativas en ninguna de las variables preoperatorias comparadas entre ambos grupos. Unicamente se observo un mayor numero de casos con larga evolucion (mas de 2 meses) entre los pacientes del grupo 1 que requirieron una retinectomia (20,7%), que en los que no fue necesaria (3,7%) (p=0,04). Conclusion: La aparicion de fenomenos de acortamiento retiniano es frecuente en la VRP. Son necesarios mas estudios para caracterizar mejor esta presentacion clinica de la VRP y para conocer los mecanismos patogenicos que la provocan. EnglishPurpose: To identify the clinical characteristics of patients developing retinal shortening due to intraretinal PVR. Methods: Observational and retrospective cohort study on 110 PVR patients operated on between 2000 and 2001. During surgery, after removing epiretinal membranes and ruling out the presence of subretinal membranes, a perfluorocarbon liquid was injected. Those cases in which retinal flattening was not accomplished, were considered intraretinal PVR (group 1). Those in which retinal flattening allowed endolaser application, were taken as the control group (group 2). Clinical features of both groups were compared by chi-square test. Results: 60 cases (54.5%, CI 95%: 40.5-68.5) showed retinal shortening (group 1). In 24 cases (21.8%, CI 95%: 12.9-30.7) complete retinal flattening was accomplished (group 2). In 26 cases (23.6%), evaluation was inconclusive. In 9 out of the 60 cases of group 1 (15%) a retinectomy was necessary to reattach the retina. Differences between both groups were not statistically significant for any of the clinical variables. However, the number of retinal detachments of more than 60 days of evolution was significantly higher in retinectomized eyes (20.7%) than in group 1 (3.7%) (p=0.04). Conclusions: Retinal shortening is a relatively frequent phenomenon in PVR. Further studies are necessary to characterize this clinical presentation of PVR and its pathogenesis.

Effectiveness and safety of nutritional supplements in the treatment of hereditary retinal dystrophies: a systematic review

The hereditary retinal dystrophies (HRDs) are a group of genetically determined disorders that result in loss of the visual function. There is a lack of standard pharmacological treatments or widely accepted nutritional recommendations. The objective of this review is to summarise the scientific evidence on the effectiveness and safety of nutritional supplements for the treatment of HRDs. We conducted a scientific literature search on Medline and PreMedline, EMBASE, SCI-EXPANDED, SSCI, and The Cochrane Library up to August 2014. Experimental, quasi-experimental and controlled observational studies were selected. Eight studies were ultimately included, seven on retinitis pigmentosa (RP) and one on Best disease. Vitamin A, vitamin E, docosahexaenoic acid (DHA), lutein and β-carotene were assessed. A 15 000 IU daily dose of vitamin A was reported to have shown a small protective effect on the progression of RP, as was the use of the carotenoids lutein and β-carotene. Different DHA doses has no effect on RP or Best disease. No supplement showed severe adverse effects in the selected studies although strong evidence of toxicity exists for high doses of vitamin A and β-carotene in certain populations. The selected studies concluded that there may be a small beneficial effect of vitamin A, lutein and β-carotene on the progression of RP. The limited evidence available indicates some well-designed additional studies on combined supplements strategies may achieve more robust conclusions. Moreover, the scarcity of evidence available on the treatment of HRD other than RP with nutritional supplements supports the need for further research efforts.