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Biomedical subjects

G R Kirkby

Publications and source records attributed to G R Kirkby.

At least 19 recordsLinked to original sources
PubMed2002

Biometry of the silicone oil-filled eye: II.

PURPOSE: In phakic silicone oil-filled eyes, removal of the silicone oil can be combined with phacoemulsification and intraocular lens (IOL) implantation. True axial length (AL) of the silicone oil-filled (viscosity 1300 centistokes) eye can be estimated from the measured AL (MAL) obtained on A and/or B scan echography, by multiplying MAL by a conversion factor of 0.71. IOL power can then be calculated using current biometry formulae (SRK/T). This study aims to evaluate the conversion factor in clinical practice. METHODS: Eleven patients undergoing combined removal of silicone oil and phacoemulsification with IOL implant were studied. Patients were divided into two groups. In Group 1 (seven patients), the IOL was placed in the capsular bag and in Group 2 (four patients) the IOL was placed in the ciliary sulcus. Calculated AL (CAL) was obtained by multiplying the MAL of the silicone oil-filled eye (as measured on A or B scan ultrasonagraphy) by the conversion factor of 0.71. IOL power was then estimated using the CAL in the SRK/T formula. The spherical equivalent of the postoperative refractive error was compared to predicted refractive error. RESULTS: The mean difference in actual and predicted refractive error was 0.74 dioptres (D) (standard deviation 0.75 D) for Group 1 and 1.31 D (standard deviation 1.4 D) for Group 2. CONCLUSIONS: The conversion factor of 0.71 corrects for the apparent increase in AL induced by silicone oil of viscosity 1300 centistokes. This allows accurate prediction of the required IOL power in eyes undergoing combined cataract extraction, removal of silicone oil and lens implant. Sulcus placement of the IOL gives a less predictable result than placement in the capsular bag.

Biometry↗
PubMed2002

Arrangements for the management of urgent retinal detachments in the United Kingdom and Eire in the year 2000: results of a survey.

PURPOSE: To ascertain the current provision of facilities for the management of vitreo-retinal (V-R) emergencies, and attitudes of V-R surgeons towards the management of V-R emergencies within the United Kingdom and Eire. METHODS: To obtain this information, all 82 consultant members of the Britain and Eire Association of Vitreo-Retinal Surgeons (BEAVRS) were requested to complete a 14-part postal questionnaire in the year 2000. Seventy-eight questionnaires were completed and returned. Data from the questionnaires were collated on a Microsoft Access Database and then statistically analysed using SPSS. The Student's t-test was used to assess relationships between continuous variables, and the Chi-squared and Fisher's Exact tests were used to compare non-parametric data. Analyses of the first 13 parts of the questionnaire are presented in this report. RESULTS: The majority of V-R surgeons (59%) practise in teaching hospitals. There are greater numbers of V-R surgeons per unit in teaching hospitals as compared to District General Hospitals (DGHs). Ophthalmic theatre and ophthalmic theatre staff availability are theoretically high (92.3% and 84.6% respectively) and evenly distributed between teaching hospitals and DGHs, but in reality, access may be difficult. Most V-R surgeons take part in an on-call rota with general ophthalmology colleagues. This formal commitment may be infrequent. Only a small proportion of V-R surgeons (28.3%) officially provide a continuous fixed on-call V-R rota, though in practice, a larger proportion do seem to provide this type of cover informally. Most V-R fellows are located in teaching hospitals (89.5%), and are usually on either a formal or informal on-call rota. Only one unit has a formal continuous on-call rota for fellows allowing no more than 72 hours duty per week. The mean time given in response to the question as to the ideal time within which surgery of an acute macula on supero-temporal retinal detachment should be carried out was 29 hours. Most V-R surgeons would not support, in court, a colleague whose patient lost vision through delay in treating a macula on detachment. CONCLUSIONS: The findings of this survey have important implications for providing a reliable service and for proper cover for doctors in training.

Attitude of Health Personnel↗
PubMed2001

Pars plana vitrectomy with silicone oil in the management of combined rhegmatogenous retinal and choroidal detachment.

PURPOSE: Rhegmatogenous retinal detachment combined with spontaneous pre-operative choroidal detachment (RDCD) represents a rare but specific entity, which has in the past been associated with a poor prognosis. This study was designed to determine the efficacy of pars plana vitrectomy with silicone oil injection in the management of this very difficult vitreoretinal problem. METHODS: A retrospective analysis was carried out of 13 eyes of 13 consecutive patients who underwent vitrectomy and silicone oil exchange. RESULTS: In a total of 10 eyes (77%) the first procedure produced anatomical success. Two eyes required a further procedure to achieve retinal reattachment, producing a final anatomical success rate of 92%. CONCLUSION: Pars plana vitrectomy with silicone oil exchange is an effective technique for managing RDCD.

Adult↗
PubMed2001

Vitrectomy for retinal detachments with both peripheral retinal breaks and macular holes. An assessment of outcome and the status of the macular hole.

PURPOSE: To establish the effectiveness of vitrectomy and gas tamponade for treating retinal detachments due to peripheral retinal breaks with an associated macular hole and to discover the status of the macular hole at long-term follow-up. METHODS: Twenty-three consecutive patients with combined peripheral break and macular hole retinal detachments were treated by pars plana vitrectomy. The main outcome measures were reattachment of the retina and status of the macular hole. RESULTS: Seventy-eight percent of the operations were successful in reattaching the retina initially, improving to 87% after two patients had another operation. Three patients declined further surgery. Long-term follow-up of macular hole status was possible in 16 cases. Closure rate was 31%. CONCLUSION: Pars plana vitrectomy with gas tamponade is an effective method of treating this form of retinal detachment. Some macular holes close after this surgery.

Adult↗
PubMed2000

Pigmented paravenous retinochoroidal atrophy: a literature review supported by a unique case and insight.

Pigmented paravenous retinochoroidal atrophy (PPRCA) is a rare disorder of unknown origin characterised by bone corpuscle pigmentation accumulation along the distribution of the retinal veins. In addition there are peripapillary pigmentary changes as well as areas of chorioretinal atrophy adjacent to the perivenular pigmentary changes. The finding of PPRCA is usually incidental and does not affect vision. The literature regarding this condition is reviewed. Its natural course has been considered controversial. Observation of the initial insult leading to PPRCA has not previously been reported. A case that provides a photographic record over 20 years of the development of this condition from the initial insult, including the gradual development of the characteristic fundus appearance, is described. The initial presentation was with a sudden reduction of vision and gross diffuse macular oedema in one eye, which was rapidly followed by similar involvement of the fellow eye despite treatment. Thus it was possible to examine the patient at the stage of the initial insult, 5 years before the development of the typical and pathognomonic retinal changes of PPRCA. The clinical and electrophysiological findings are discussed, as also is the relevance of this case to the literature reviewed.

Adolescent↗
PubMed2000

The role of preoperative subconjunctival mydricaine and topical diclofenac sodium 0.1% in maintaining mydriasis during vitrectomy.

PURPOSE: To establish the role of preoperative subconjunctival mydricaine and diclofenac 0.1% in maintaining mydriasis during vitrectomy. METHODS: Fifty-seven patients were entered into the study. All were given cyclopentolate 1% and phenylephrine 2.5% preoperatively. Each patient was randomly allocated to one of three groups. In Group 1, patients received mydricaine by subconjunctival injection and diclofenac 0.1% topically preoperatively. In Group 2, patients received only subconjunctival mydricaine. Group 3 patients received only topical diclofenac preoperatively. Pupil diameter was measured with calipers before and at the end of the operation. RESULTS: There was no statistically significant difference in the change in pupil size between Groups 2 and 3. In all patients in Group 1 (who received both subconjunctival mydricaine and diclofenac preoperatively), pupil size was either maintained or increased after vitrectomy. This result was statistically significant when compared with the other groups (for Group 1 versus Group 2, P<0.005; for Group 1 versus Group 3, P<4.7x10(-06)). CONCLUSION: Topical diclofenac is useful for maintaining pupil size during vitrectomy only when used in conjunction with subconjunctival mydricaine, especially in patients in whom prolonged surgery is anticipated.

Adolescent↗
PubMed1999

The posterior vitreous detachment clinic: do new retinal breaks develop in the six weeks following an isolated symptomatic posterior vitreous detachment?

PURPOSE: Symptomatic posterior vitreous detachment (PVD) is sometimes associated with sight-threatening retinal tears or retinal detachment. Patients are usually reviewed twice because it is believed that retinal breaks may develop within 6 weeks of a PVD and as such the management of a PVD consumes significant resources. The aim of this study was to find the frequency of retinal breaks developing within 6 weeks of an isolated PVD using the same experienced examiner at both visits. METHOD: Patients presenting to the eye casualty with symptomatic PVD were examined by the casualty staff. Those with a retinal break or retinal detachment were referred directly for treatment and those with only a PVD were seen within 8 days in the PVD clinic. They were examined by a vitreo-retinal Fellow using indirect ophthalmoscopy and a 20 D lens with scleral indentation. The position and nature of any retinal abnormalities were noted and compared with those described in the casualty notes. Those with sight-threatening breaks were referred for treatment and the remainder were reviewed 5 weeks later when the presence of any new breaks was noted. RESULTS: One hundred and seven patients were referred to the PVD clinic over a 6-month period, of whom 2 did not have a PVD. At the first visit to the PVD clinic 6 patients had round holes anterior to the equator, 2 had equatorial horseshoe tears and 1 had lattice with holes. At the second visit, 2 additional patients had round holes anterior to the equator but in both the retina had been obscured by vitreous haemorrhage at the first visit. No patient in whom a full examination was possible at the first visit developed further retinal pathology. CONCLUSION: These results demonstrate the need to perform a full examination of the peripheral retina with scleral indentation at the time of presentation and emphasise the importance of finding a vitreous haemorrhage following a symptomatic PVD. If no retinal breaks are detected by thorough examination at presentation, further reviews, in the absence of increasing symptoms, may not be necessary.

Adult↗
PubMed1999

Biometry of the silicone oil-filled eye.

PURPOSE: The advent of silicone oil tamponade has resulted in improved success rates in complicated retinal detachment surgery. Its use, however, can induce cataract formation in phakic eyes. In selected patients, removal of silicone oil can be combined with phacoemulsification of the cataract and intraocular lens (IOL) implantation, thus avoiding a further operation. This, however, poses a problem when trying to decide the power of IOL to be used, since the echographically measured axial length (AL) of an eye is greater in the presence of silicone oil. We performed ultrasound examination in the presence of silicone oil of viscosity 1300 centistokes, in order to determine whether the measured AL varied from the true AL by a constant factor. METHODS: The ALs of 7 phakic eyes were measured by A-mode echography, with and without silicone oil of viscosity 1300 centistokes in the posterior segment. The retina was attached in all cases. The control group consisted of 6 phakic eyes with attached retinae undergoing vitrectomy without the use of silicone oil. The ALs in the control group were measured before and after vitrectomy. RESULTS: The mean ratio of true AL to measured AL in the presence of silicone oil was 0.71 (standard deviation 0.01; range 0.70-0.73; median 0.71) in the 7 eyes in this study. In the control group, vitrectomy appeared to have no significant effect on AL. CONCLUSIONS: We have established a constant which corrects for the apparent increase in AL induced by silicone oil of viscosity 1300 centistokes. This conversion factor, when used in existing biometry formulae (SRK/T), allows estimation of the power of IOL required in eyes undergoing combined cataract extraction, removal of silicone oil and lens implantation.

Biometry↗
PubMed1998

The role of ophthalmic triage and the nurse practitioner in an eye-dedicated casualty department.

PURPOSE: To evaluate the appropriateness of triage decisions in a busy ophthalmic casualty department and to assess the diagnostic and management skills of eye-dedicated nurse practitioners. METHODS: Three hundred and one consecutive patients attending the Birmingham and Midland Eye Centre (BMEC) accident and emergency (A&E) department over a 2 week period were included in this prospective study. Patients were categorised in terms of urgency in concordance with strict guidelines, and the agreement between the final diagnosis and this system of prioritisation was then investigated. To evaluate nurse practitioner (NP) skills, all patients seen and managed by a NP were also assessed by the most senior doctor in casualty at the time in a masked fashion. Waiting times and a breakdown of waiting times were also calculated. RESULTS: Upon establishment of a diagnosis, triage category allocation was found to be appropriate in all 301 cases. Fifty patients (16.67%) were seen by the NP. Of these the supervising doctor concurred with the NP diagnosis in all cases and with the proposed management in 96% of cases. The mean waiting time (+/- SD) was 83.43 +/- 45.84 min, with a range of 5-335 min. The delay before being attended to was greater for less urgent cases as categorised by the triage system. CONCLUSION: This study confirms the high standard of diagnostic and management skills of the ophthalmic NP and indicates that the triage system of patient prioritisation is accurate. Waiting times in the A&E department remain unacceptable and ways of addressing this include improved ophthalmic training of general practitioners, diverting a greater proportion of non-acute cases to the primary care clinic and expanding the role of the NP.

Adolescent↗
PubMed1998

Simultaneous posterior chamber intraocular lens implant combined with vitreoretinal surgery for intraocular foreign body injuries.

UNLABELLED: To evaluate the safety of simultaneous posterior chamber intraocular lens (IOL) implant combined with complex vitreoretinal surgery for ocular trauma due to intraocular foreign body (IOFB). METHODS: We undertook a retrospective analysis of 10 patients who had undergone simultaneous cataract extraction, vitreoretinal surgery, removal of IOFB and posterior chamber IOL implant, for ocular trauma due to IOFB. The visual outcome and complications were noted. The surgical procedure is described. RESULTS: Ten young, male patients were followed for 5-30 months post-operatively. The post-operative visual acuity in the operated eye remained the same or improved as compared with their pre-operative vision. Eight patients had a visual acuity of 6/9 or better. One patient developed post-operative infective endophthalmitis. Three patients had retinal detachment post-operatively. The IOL was stable in all patients. CONCLUSIONS: Simultaneous posterior chamber IOL implant with vitreoretinal surgery is safe in selected cases of severe ocular trauma due to IOFB. It allows early visual rehabilitation of young, working patients.

Adult↗