In the 25 years since the introduction of pars plana vitrectomy (PPV) into the UK, there have been dramatic changes in the surgical management of posterior segment pathology. Initially, these were largely exploratorythe new found ability to access the structures and surgical pathology of the posterior segment enabling a wide range of treatment methods previously impossible to contemplate, let alone accomplish. Control of the intraocular environment, improved delivery of internal tamponade and the design of a battery of common gauge micro instruments led rapidly to an explosion of innovative techniques.

During the past 15 years, the initial explosion has given way to a (largely) quiet revolution, with the development and refinement of established and proved methods and their direction along logical paths of treatment, in conditions which hitherto caused severe and permanent loss of sight.

The paper by Ah-Fat et al, in this issue of the BJO (p 396), reminds us that PPV offers an alternative to previously effective and well tried methods of treatment, as well as providing the means of treating hitherto untreatable conditions and those arising as a consequence of new techniques in other fields of eye surgery. The authors make the disturbing observation, however, that their successful development of PPV techniques (coupled no doubt with the pressures of uncertain outcomes and clinical governance) has led to other ophthalmologists referring cases to their unit in greatly increased numbers, such that the time from diagnosis to surgery has increased.

Thus, while more sophisticated surgery has improved anatomical results, there has been a concurrent increase in the proportion of rhegmatogenous retinal detachments (RRDs) in which the macula is detached at the time of operation, with (possibly) a detrimental effect on visual outcomes.

A number of studies have shown that PPV, combined with internal tamponade, is effective in the treatment of RRDs,^1-3 particularly those with complex retinal breaks and especially in pseudophakic and aphakic eyes. Similarly, it is generally acknowledged that PPV, combined with adjunctive techniques and various forms of internal tamponade, is effective in the surgical management of proliferative fibrovascular^4 5 and fibrocellular disease,^6 7 macular holes,^8-10 and dropped lens nuclei.^11 12 Its role in the management of age related macular degeneration (ARMD) is much less clear and the value of surgical removal of subretinal neovascular membranes,^13 14 retinal pigment epithelial cell transplantation,¹⁵ and retinal translocation^16 17 has yet to be proved.

The results of the study by Ah-Fat et al serve to highlight one of the pitfalls encountered when attempting to evaluate improvements in health care by looking only at a narrow spectrum of outcome measures. They also demonstrate the dangers of becoming a victim of one's own success, or to be more accurate, patients becoming the victims of their surgeons' success. Indeed, in the case of surgery for ARMD, one might question the wisdom of inviting publicity for a surgical method of, as yet, unproved value which will inevitably place even greater demands on an already overburdened service.

Given that clinical governance will increase the pressure on surgeons to achieve results in line with, or better than, national audit figures and that provision of resources will depend on the conduct of evidence based medicine, vitreoretinal surgeons would be well advised to contain their surgical enthusiasm and offer only well proved treatments to their patients, unless or until they have the knowledge and resources to offer them more.

The trends in vitreoretinal surgery identified by Ah-Fat et al provide a useful insight into the problems we are likely to experience in the future, in all branches of the specialty, in the face of ever increasing demands and limited resources. As it seems inevitable that expansion of the role of vitreoretinal surgery in the treatment of an ever widening range of conditions and increased tertiary referral to specialised vitreoretinal units will continue, under the watchful gaze of the National Institute for Clinical Excellence and Commission for Health Improvement, we must be ready to provide the appropriate resources.

This means that trusts must not only make available the financial wherewithal to employ more vitreoretinal surgeons and provide equipment, but they must also encourage teaching, training, and research. Only in this way can the knowledge, expertise, and spirit of inquiry be developed to ensure that new surgical methods are properly designed and evaluated before being offered to their patients. Not only is the promised consultant expansion vitally important, but high quality fellowship programmes, clinical academic appointments, and Culyer funding must all be encouraged if we are to support the training and research necessary to develop new and better vitreoretinal surgical methods for our patients in the future.