PubMed Health⌕ Search

Biomedical subjects

P K Leaver

Publications and source records attributed to P K Leaver.

At least 19 recordsLinked to original sources
PubMed1992

Four-quadrant local anaesthesia technique for vitreoretinal surgery.

We report our experience of a recently described local anaesthetic technique which seeks to avoid risk of perforation of the globe, damage to the optic nerve, or injection into the subarachnoid space, whilst providing prolonged and reliable anaesthesia. A prospective series of 19 patients who underwent vitreoretinal surgery using this technique were compared with 19 patients who had retrobulbar anaesthesia for cataract extraction. The vitreoretinal group had excellent akinesia and very good anaesthesia, allowing prolonged retinal reattachment surgery lasting up to 3 hours. Patient evaluation of discomfort or pain experienced in the two groups was assessed using a visual analogue pain score chart. The pain scores for the two groups were not significantly different (p = 0.03) and 16 of 19 patients in each group (84%) experienced only slight pain or less. Satisfaction with local anaesthesia, in both groups, was also assessed by asking patients which method of anaesthesia they would prefer if future surgery were to be performed. In the vitreoretinal group, 18 of 19 patients expressed a preference for local anaesthesia and in the cataract group 17 ot 19 also favoured local anaesthesia. The vitreoretinal patients' median pain score was 0 compared with 1 for the cataract patients. This study demonstrates that local anaesthesia provides pain relief for vitreoretinal surgery which is comparable to the experience of patients undergoing cataract surgery by retrobulbar anaesthesia. The technique described can provide successful local anaesthesia for vitreoretinal procedures. The success of this technique for pain relief and akinesia calls for a reappraisal of the number of patients suitable for vitreoretinal surgery under local anaesthesia.

Anesthesia, Local↗
PubMed1992

Mathematical modelling of retinal tear formation: implications for the use of heavy liquids.

When force is applied to detached retina it elevates, stretches, and becomes irreversibly deformed. Finally it tears, and the timing and location of tear formation are determined by the distribution of stress within the retina. This stress distribution is dependent upon the retinal contour. We have tested this using retinas of freshly enucleated bovine eyes. A suture was attached to isolated retinal tissue using butylacrylate (Histoacryl) glue and traction was applied to this suture so stretching the retina. We present a mathematical model of the in vitro data obtained, with predictions for local retinal internal tensions. We show that these are altered by the addition of hydrostatic forces due to the presence of heavy liquids. These findings have implications for epiretinal membrane dissection during surgery and for the use of heavy liquids during membrane peeling.

Animals↗
PubMed1991

Removal of silicone oil--rewards and penalties.

Silicone oil is a useful tool in retinal reattachment surgery in selected cases, but complications, particularly cataract, glaucoma and keratopathy, have led to worries about its use for prolonged internal tamponade. Removal of silicone oil has been recommended to preempt or reverse these complications. A retrospective review of 120 eyes in which temporary silicone oil tamponade had been employed is presented. One hundred and twelve eyes were examined six months and two years after removal of silicone oil. Retinal redetachment occurred in 21 eyes (19%). Cataract formation was delayed by early removal of silicone oil, but after two years the majority of eyes had undergone surgery for cataract or had developed lens opacities. Removal of silicone oil was ineffective in reversing an established pressure rise in nearly all cases. Three phakic eyes developed glaucoma after removal of silicone oil but no new cases occurred in phakic eyes in the two years following silicone oil removal. Keratopathy was uncommon and was arrested and occasionally reversed by silicone oil removal. Visual acuities improved in the majority of eyes after removal of silicone oil.

Adult↗
PubMed1990

Extended criteria for vitrectomy and fluid/silicone oil exchange.

The results of vitrectomy combined with fluid/silicone oil exchange at six months after surgery in 39 eyes with complex retinal detachments without (initially) severe proliferative vitreoretinopathy, proliferative diabetic retinopathy or giant retinal tears, are reported. Eyes with detachments as a result of macular holes, large multiple or posterior breaks, and eyes which had undergone previous, unsuccessful vitreoretinal surgery are included. In 90% the retina remained reattached, with functional improvement in 72%. These findings, together with the relatively low incidence of complications observed, lead us to recommend this technique in the management of selected detachments falling outside the parameters within which its use is generally accepted.

Cataract↗
PubMed1989

Vitrectomy and fluid/silicone-oil exchange for giant retinal tears: 5 years follow-up.

A series of 64 eyes, in 64 patients with giant retinal tears, treated by vitrectomy and fluid/silicone-oil exchange, has been reviewed after 5 years. Anatomical success was achieved in 73% of cases and visual function in successful cases ranged from 6/6 to NPL; 66% achieved acuities of 6/60 or better and 32% had vision of 6/18 or better. These results compare favourably with those in a previous series reported after 6 months and 18 months. Epiretinal membrane proliferation and shortening accounted for the majority of retinal redetachments while macular abnormalities, especially pucker, were responsible for a poor visual outcome. Glaucoma is the most serious long-term complication of the surgical method and occurs most frequently in aphakic eyes. Retention of the crystalline lens, whenever possible, the creation of a 6 o'clock iridectomy in aphakic eyes, early removal of silicone oil and a conservative approach to the use of scleral buckles are recommended.

Adolescent↗
PubMed1989

Retinal detachments--when to refer? Identifying the complicated case.

Cases of retinal detachment are usually referred by one ophthalmologist to another, because of their complexity. The complicated nature of such cases can be judged by their likely response to conventional methods of retinal reattachment surgery. When the causative retinal breaks cannot be identified or closed by conventional means, it is reasonable to call detachments complicated. The prompt identification of such cases and their referral, if appropriate facilities and expertise to undertake them are not at hand, are essential steps in the correct management of rhegmatogenous retinal detachments.

Humans↗
PubMed1989

Silicone oil in the aphakic eye: the influence of a six o'clock peripheral iridectomy.

Complications after six months, in a series of 44 aphakic eyes treated by vitrectomy and fluid/silicone-oil exchange with six o'clock (Ando) peripheral iridectomy, are reported. Comparisons are made with the complications after six months in a similar series treated prior to the introduction of the six o'clock iridectomy. It is concluded that a patent six o'clock iridectomy is effective in reducing the complications of intraocular silicone oil in the aphakic eye.

Adolescent↗
PubMed1988

Behaviour of intraocular gases.

The changes in volume of intraocular bubbles of air, sulphur hexafluoride, perfluoropropane and mixtures of these gases, were studied in human eyes, following vitrectomy for treatment of retinal detachment. The implications of these findings, for the provision of optimal internal tamponade in the treatment of retinal detachment, are discussed.

Air↗
PubMed1988

Retinal compression folds.

Twelve cases of retinal compression folds occurring after successful retinal re-attachment surgery are reported. In all 12 eyes surgery included the use of a circumferential buckle, internal tamponade with gas or silicone oil and drainage of sub-retinal fluid. The mechanism of retinal fold formation is discussed.

Female↗
PubMed1987

Intraocular argon laser photocoagulation.

Intraoperative photocoagulation using an endolaser delivery system is an important recent development in the field of vitreous microsurgery. Endolaser photocoagulation is indicated in a wide variety of vitreoretinal disorders and offers important advantages over previous techniques of endophotocoagulation using xenon energy. We review our experiences of argon laser endophotocoagulation to identify the role of this technique, the potential hazards and stringent precautions required for theatre personnel.

Animals↗
PubMed1987

Closed microsurgery for the sequelae of neovascularisation from veno-occlusive retinopathies.

Our experience of closed microsurgery for vitreous haemorrhage and/or traction retinal detachment complicating extraretinal neovascularisation after retinal vein occlusion or Eales' and Behçet's periphlebitis is discussed. Many of these eyes represented a relatively simple management problem, but the visual outcome was often compromised by intrinsic macular damage. Some eyes had complicated vitreoretinal relationships which presented unexpected technical difficulties, while persisting retinal ischaemia posed the risk of rubeosis iridis or post-operative vitreous haemorrhage unless scatter endophotocoagulation was used.

Cataract Extraction↗
PubMed1987

Retinal relieving incisions.

Retinal relieving incisions were undertaken during closed microsurgery for the treatment of retinal detachment complicated by retinal shortening as a result of incarceration or irresectable epiretinal membranes. In 16 of 20 eyes the retina remained attached after a minimum follow up of six months. Visual acuity of 2/60 or better was achieved in eleven of the 20 eyes and seven eyes had an acuity of 6/60 or better. Retinal relieving incisions are required in a minority of retinal re-attachment procedures and are compatible with useful visual function.

Adult↗
PubMed1986

Vitrectomy and fluid/silicone-oil exchange for giant retinal tears: results at 18 months.

Sixty-five eyes with giant retinal tears previously reviewed at 6 months after vitrectomy and fluid/silicone-oil exchange were again reviewed 18 months after surgery. The retina remained attached in 54 eyes (83%), and of these 32 (57%) had visual acuities of 6/60 or better. Poor acuities were attributed in most cases to cataract associated with silicone-oil contact or macular damage from preoperative macular detachment. Glaucoma occurred chiefly in those eyes which were aphakic prior to surgery, or were rendered aphakic at surgery, but did not influence the visual outcome at this stage. Encouraging results of surgery after 6 months were confirmed after 18 months, although the level of vision had fallen in some cases due to the development of lens opacities.

Adolescent↗
PubMed1986

Xenon-arc endophotocoagulation during vitrectomy for diabetic vitreous haemorrhage.

The value of scatter xenon-arc endophotocoagulation in stabilising eyes with respect to post-operative rubeosis iridis and vitreous haemorrhage is demonstrated in a consecutive series of 100 vitrectomies undertaken for diabetic vitreous haemorrhage. Seventy eyes ultimately achieved 6/36 or better vision. Endophotocoagulation of untreated ischaemic retina is recommended in eyes undergoing vitrectomy for diabetic vitreous haemorrhage.

Diabetes Complications↗
PubMed1986

Long-standing retinal detachments--the role of internal tamponade.

Internal tamponade with gases or silicone-oil is useful in the management of long-standing retinal detachments complicated by retinal folds, posterior breaks or PVR and to close breaks after vitrectomy. Such complications and the needs for vitrectomy are particularly common in cases of persistent or recurrent long-standing detachment after unsuccessful retinal reattachment surgery.

Air↗