Cytokines in human intraocular inflammation

The presence of interleukin 6 (IL-6), interleukin 1 (IL-1), interleukin 2 (IL-2) and tumour necrosis factor (TNF) was investigated in vitreous and aqueous aspirates from eyes undergoing vitrectomy for the treatment of different inflammatory conditions. Cadaveric vitreous from 10 normal subjects were used as controls. IL-6 was observed in 5 specimens from eyes with idiopathic uveitis (range = 26-264 pg/ml), in 2 specimens from eyes with uveitis complicated with retinal detachment (28 and 279 pg/ml, respectively), in 6 samples from eyes with diabetic retinopathy (range = 5-480 pg/ml), in one sample from an eye with phacolytic glaucoma (1190 pg/ml) and in one specimen from an eye with Behçet's disease (366 pg/ml). Although IL-1 was detected in 80% of all the samples investigated, concentrations of this cytokine greater than 3 pg/ml were only observed in 2 specimens from eyes with uveitis (5 and 20 pg/ml, respectively) and 2 samples from eyes with diabetic retinopathy (3 and 31 pg/ml, respectively). TNF was present in 3 specimens from eyes with uveitis (range = 2-24 pg/ml) and 1 sample from eyes with diabetic retinopathy (4 pg/ml), but was not detected in the eyes with phacolytic glaucoma or Behçet's disease. IL-2 (less than 0.1 U/ml) was detected in one sample from an eye with uveitis, one specimen from an eye with uveitis complicated with retinal detachment and 2 samples from eyes with diabetic retinopathy. None of the cytokines measured were detected in any of the control vitreous. The present observations suggest that cytokines, particularly IL-6 and IL-1, may act as local amplification signals in pathological processes associated with chronic eye inflammation.

Cytokines in proliferative vitreoretinopathy

This study determined the presence of interleukin 1 (IL-1), interleukin 6 (IL-6), tumour necrosis factor alpha (TNF alpha), tumour necrosis factor beta (TNF beta), interferon gamma (IFN gamma), transforming growth factor beta 2 (TGF beta 2) and fibroblast proliferation activity (FPA) in vitreous aspirates from eyes undergoing vitrectomy for the treatment of retinal detachment complicated by proliferative vitreoretinopathy (PVR) or uncomplicated retinal detachment (RD). Cadaveric vitreous from normal subjects were used as controls. The results showed that IL-1 and IL-6 predominated in vitreous from eyes with PVR or RD, and that concentrations of IL-6 greater than 20 pg/ml were more frequently found in PVR than in RD (p = 0.031) or control specimens (p = 0.006). Low levels of TNF alpha were observed in 4/18 eyes with PVR, 1/15 eyes with RD and 1/15 control vitreous, and small concentrations of TNF alpha were seen in 3/18 eyes with PVR, 1/15 eyes with RD and 2/15 control vitreous. IFN gamma was detected in 12/18 eyes with PVR, but only in 5/15 eyes with RD (p = 0.048) and 6/15 control specimens. TGF beta 2 was present in all vitreous samples at concentrations ranging from 100 to 4,500 pg/ml with no significant differences among the three groups. Control vitreous possessed the greatest FPA when compared with vitreous from eyes with PVR (p = 0.031) or RD (p = 0.048). These observations provide further evidence that cytokine-mediated pathways of inflammation are involved in the pathogenesis of PVR and point to the possible involvement of IL-1, IL-6 and IFN gamma in cellular interactions leading to chronicity.

Perforation of the globe--a complication of peribulbar anaesthesia

Peribulbar anaesthesia has been recommended as a safer alternative to retrobulbar anaesthesia. We report a case of perforation of the globe sustained during peribulbar anaesthesia which resulted in blindness. Orbital injections are potentially dangerous, be they peribulbar or retrobulbar. To minimise the risk, short, blunt needles are advocated for the peribulbar route.

Subretinal gas

Two cases of subretinal gas are described. The circumstances in which this complication arose are important in understanding the mechanism by which gas gains access into the subretinal space. Evacuation of subretinal gas by posturing should be avoided as this leads to an increase in the extent of the retinal detachment and its extension anterior to involve the nonpigment epithelium of the pars plana. A technique for removing subretinal bubbles of expanding gases using vitrectomy and fluid/gas exchange is recommended.

Immunoglobulins in paired specimens of vitreous and subretinal fluids from patients with rhegmatogenous retinal detachment

Evidence suggests that there is a net movement of fluid through the retinal break in eyes with rhegmatogenous retinal detachment, this net movement being directed from the vitreous humour into the subretinal space. However, it remains uncertain how much fluid exchange occurs in both directions across such breaks. The concentration ratios of IgG/IgM or IgA/IgM, derived from assay of immunoglobulins in vitreous humour, subretinal fluid, and serum from a group of 19 such patients, suggest a lack of free, two-directional, fluid movement across the retinal break. Furthermore the IgG/IgM ratios for the two intraocular fluids were significantly greater than that of serum, this suggesting that these intraocular fluids are formed, at least in part, by a selective transduction of serum.

Results and complications of conventional repair of bullous retinal detachment using posterior segment air injection

The aims of this retrospective study were to determine the outcome of retinal detachment repair using the drainage, air injection, cryotherapy and explant surgical sequence ('D-ACE' technique) for bullous retinal detachments and also to identify the complications attributable to the injection of the gas. The D-ACE technique was used to repair 206 detachments over a ten year period of which 138 (67%) were successfully re-attached with a single operation. The sub-group of these patients (n = 66) with bullous retinal detachments who would be considered suitable for repair using the technique of pneumoretinopexy (PR) showed a single operation success rate of 85% after D-ACE. Complications attributable to the gas injection occurred in 18 eyes (8.5%). In only four of these (1.9%) did retinal surgery ultimately fail as a result of complications caused by injection of the gas, which represents 10% of all the failures. The results of this series show that the serious complication rate from injecting air into the vitreous cavity is low and that the success rate for treating relatively uncomplicated bullous retinal detachments using the D-ACE technique compares favourably with the results of other published series using either the D-ACE procedure or pneumoretinopexy.

Diplopia after retinal detachment surgery

Diplopia following retinal detachment usually responds to simple measures. Fifteen out of 311 cases developed diplopia lasting more than three months after conventional retinal detachment surgery. Binocular single vision was restored in 12 of the 15 cases (80%). The mean follow-up was four years. Diplopia was eliminated stepwise. If prisms were ineffective, our first surgical procedure was removal of the scleral buckle. If the retina was flat, we were prepared to remove the buckle early. When diplopia persisted after buckle removal, we proceeded to strabismus surgery. Our most consistent results followed strabismus surgery on the untreated eye. Prisms alone restored binocular single vision in six patients (40%), one of whom preferred to adopt a compensatory head posture. Removal of the scleral buckle restored binocular single vision in three patients (20%), with the help of a prism in one case and a compensatory head posture in another. Binocular single vision was restored after buckle removal and strabismus surgery in three further patients (20%), one requiring a prism in addition. Binocular single vision was not restored in three patients (20%).

Pars plana vitrectomy for retinal detachment with unseen retinal holes

A study was made of a consecutive series of 47 cases of rhegmatogenous retinal detachment treated by pars plana vitrectomy in which no holes were identified preoperatively. The view of the fundus during preoperative examination varied from being totally clear to completely obscured by media opacities. The role of pars plana vitrectomy in finding retinal holes peroperatively is considered. The incidence of discovering holes and the locations of those found at the time of surgery are presented. The significance of these findings is discussed. Where the preoperative view was good and the extent of proliferative vitreoretinopathy (PVR) did not exceed grade C2, retinal reattachment was achieved in 75% of the cases. A review made of a similar group of patients treated with conventional retinal buckling before the introduction of pars plana vitrectomy revealed that successful retinal reattachment was achieved in 70% of cases. The study concludes that pars plana vitrectomy, while being necessary for cases of rhegmatogenous retinal detachment when the view of the retina is obscured, will not always reveal the presence of a retinal break. If the preoperative view of the retina was good and the extent of PVR did not exceed grade C2, pars plana vitrectomy did not seem to offer obvious advantages over conventional buckling procedures.

Candida endophthalmitis: a complication of prolonged intravenous therapy and antibiotic treatment

Four patients with candida endophthalmitis are discussed; three had received prolonged intravenous therapy as well as multiple and varied courses of antibiotics for underlying gastro-intestinal disease; one was an intravenous drug abuser. The visual acuity improved dramatically in two of the five affected eyes but in the remaining three eyes remained at 6/60 or less. Visual prognosis is directly related to early diagnosis and treatment, which should include pars plana vitrectomy and systemic antifungal therapy.

The treatment of macular holes by pars plana vitrectomy and internal air/SF6 exchange

The results of a series of patients with full-thickness macular holes treated by pars plana vitrectomy are described. A air/gas mixture is used to tamponade the retinal hole and no adhesion is applied. Eleven eyes, including six high myopes, were treated using this method and sustained reattachment was achieved in eight eyes (73%). Three cases failed due to the presence of preretinal membrane formation and retinal shortening. This method is technically easy, allows good tamponade of the retinal hole with controlled internal drainage of subretinal fluid, and appears much safer than previously described techniques.

Surgical treatment of superior bullous rhegmatogenous retinal detachments

The results in 90 patients with superior bullous rhegmatogenous detachments operated on over a period of 10 years are presented. In only 70% of cases treated by scleral buckling, with or without drainage of subretinal fluid, was retinal reattachment achieved with a single operation. More recently the treatment of patients by external drainage, air injection into the vitreous cavity, and subsequent buckling has improved the success rate to 96%. It is suggested that the latter method be the surgical treatment of choice in such cases.

Aphakic retinal detachment

A study of 132 cases of aphakic retinal detachment (ARD) following mainly intracapsular cataract surgery has been made. Forty-nine cases (37%) were found to have vitreous incarcerated into the cataract section out of a total of 54 (41%) cases who had suffered a vitreous complication during cataract surgery. A study of the characteristics of ARD reveals that those cases having had a vitreous complication in the management of their cataracts are more likely to develop detachment within three months than those not suffering from such a complication. The occurrence of these early post-extraction retinal detachments is not influenced by the presence of underlying axial myopia. When we compared ARD in patients whose cataract extractions had been complicated by vitreous incarceration with those ARDs following uncomplicated cataract surgery, we found that the characteristics of the detachments were very similar. Thus distribution of underlying myopia, extent of detachment, length of time of detachment, and multiplicity and type of retinal holes were generally similar. However, ARD following complicated cataract surgery is more likely to suffer from periretinal fibrosis. The findings confirmed the risk of ARD following complicated intracapsular cataract surgery and support the tendency to perform the extracapsular operation.

Shifting subretinal fluid in rhegmatogenous retinal detachment

In a consecutive series of 470 cases of rhegmatogenous retinal detachment 25 (5%) were found to have shifting subretinal fluid (SRF) at the preoperative examination. The study showed that the association between SRF and rhegmatogenous retinal detachment is unusual but not rare. Shifting SRF was most often associated with aphakic and longstanding retinal detachment, and found in cases in which the retinal holes were small.

Astigmatism following retinal detachment surgery

Eighty-three patients on whom successful retinal detachment had been performed were studied to note astigmatic changes following surgery. In the majority of cases the errors following such surgery are of no great clinical importance. However, in some situations a high degree of astigmatism may be produced. This study showed that these sequelae are particularly likely after radial buckling procedures, and surgeons favouring these techniques should be aware that astigmatic errors can be induced. The astigmatic errors may persist for several years after surgery.