Biomedical subjects

C M Kirkness

Publications and source records attributed to C M Kirkness.

At least 19 recordsLinked to original sources

PubMed1992

Criteria for intravitreal antibiotics during surgical removal of intraocular foreign bodies.

Published opinion supports the early use of prophylactic antibiotics soon after presentation of a potentially contaminated intraocular foreign body (IOFB) in the posterior segment, preferably within 12 hours of trauma when the visual acuity is still good. Recommended treatment includes topical, subconjunctival, parenteral and especially intravitreal antibiotic therapy to reduce the chance of endophthalmitis. Intravitreal therapy should include gentamicin with vancomycin or clindamycin to cover Bacillus spp., since this organism is responsible for half the endophthalmitis cases and produces beta-lactamase giving resistance to penicillins and cephalosporins. Intravitreal therapy is important because systemic and topical antibiotics do not penetrate the globe in sufficient concentration to control a fulminant infection associated with damaged tissue. Early therapy is essential, as delaying treatment until endophthalmitis occurs is less likely to save useful vision. All vitreous aspirated, plus pus if present, and the IOFB should be cultured for bacteria and fungi to identify pathogens and gain antibiotic sensitivities. The prevention of IOFB-associated endophthalmitis requires early recognition of the IOFB and enthusiastic antibiotic therapy at the time of its removal.

Anti-Bacterial Agents↗

PubMed1992

Risk factors for the development of postkeratoplasty glaucoma.

From a database of 1,122 penetrating keratoplasties performed under the care of the surgeons of the Corneal Clinic, Moorfields Eye Hospital (London, U.K.), 153 (14%) were identified as being complicated by postkeratoplasty glaucoma. The relative risk for its development varied with the indication for keratoplasty. Keratoconus had the lowest incidence along with some dystrophies, such as macular or granular dystrophy, and these were taken as the baseline for comparison. Anterior chamber dysgenesis syndromes had the highest risk among the indications for keratoplasty. Combined cataract or lens implant surgery was also found to be a risk factor, with anterior vitrectomy, anterior segment revision, and anterior chamber lens implant removal representing a greater risk than extracapsular extraction and posterior chamber lens implantation. Postkeratoplasty glaucoma was also strongly associated with peripheral anterior synechiae formation seen after keratoplasty.

Cataract Extraction↗

PubMed1992

Corneal endothelial irregularity with long-term contact lens wear.

A case is presented of a 49-year-old woman who has worn hard contact lenses for 26 years. Specular microscopy of the central corneal endothelium revealed marked bilateral polymegethism and a large coefficient of variation in cell size. Of greater significance was the presence of clumps of small cells. This may be related to the way the corneal endothelium responds to long-term anoxia.

Cell Count↗

PubMed1992

Coexistent corneal disease and glaucoma managed by either drainage surgery and subsequent keratoplasty or combined drainage surgery and penetrating keratoplasty.

The results of penetrating keratoplasty following trabeculectomy in 26 eyes where there was coexistent corneal disease and glaucoma are presented. Patients were aged 16-80 years at the time of drainage surgery (mean = 51 years) and there was a mean of 33.5 months between trabeculectomy and keratoplasty. The mean pressure fell from 35.3 mm Hg prior to trabeculectomy to 14.9 mm Hg at the time of keratoplasty and 20 mm Hg 12 months after keratoplasty. There was a 0.45 probability of maintaining normal intraocular pressure with medication at 5 years after keratoplasty; and a similar graft survival probability. The probability of maintaining both a clear graft and a normal pressure was only 0.27 at 5 years. In another 22 eyes combined trabeculectomy and penetrating keratoplasty was performed. Patients' ages ranged from 21-82 years (mean 55) at surgery, and 73% were aphakic. The intraocular pressure dropped from a mean of 28.9 mm Hg preoperatively to 14 mm Hg at 12 months. There was a 5 year probability of 0.7 of maintaining a clear graft but if both a clear graft and normal intraocular pressure are considered then the probability falls to 0.5 at 5 years. The hazard ratio for intraocular pressure control and graft survival between the two groups suggests that combined surgery may offer a better prognosis.

Adolescent↗

PubMed1992

Recurrent malignant melanoma of the corneal stroma: a case of 'black cornea'.

A 39-year-old Caucasian woman with a history of recurrent conjunctival melanoma of her right eye developed an intrastromal heavily pigmented malignant melanoma, which involved the whole corneal diameter. The patient was treated by corneoscleral lamellar keratoplasty and there has been no evidence of recurrent neoplasm during 4 years of follow-up. This apparently unique presentation of malignant melanoma of the cornea is illustrated and the differential diagnosis of corneal pigmentation is discussed.

Adult↗

PubMed1991

Refractive surgery for graft-induced astigmatism after penetrating keratoplasty for keratoconus.

Of a series of 201 corneal transplants for keratoconus over a 20-year period, 42 grafts (39 eyes of 38 patients) required further surgery because of intolerable astigmatism (range, -3 diopters [D] to -18 D; mean, 8.9 D). Relaxing incisions, compressive resuturing, and augmented relaxing incisions were the techniques used. All procedures resulted in a similar mean reduction in cylinder -3.6 to 5 D, but the outcome with augmented relaxing incisions was less predictable. Six grafts required two or more procedures for a satisfactory outcome. All patients had corrected visual acuity of 20/30 or better after surgery, and 75% had visual acuity of 20/20 or better. The cumulative time until 90% of the grafts had useful vision was 32 months after refractive surgery. Relaxing incisions offer the prospect of more rapid visual rehabilitation than compressive resuturing.

Astigmatism↗

PubMed1991

Is raised intraocular pressure a bad prognostic sign in acute corneal graft rejection?

One hundred and forty acute corneal rejection episodes in 94 patients were studied retrospectively. Sixteen episodes in 15 eyes were associated with raised intraocular pressure (IOP) on admission, three of whom had had previously elevated IOP. At six weeks, six (37.5%) still required hypotensive therapy. Five eyes with raised IOP at rejection had lost vision at six weeks. Five of the six eyes with graft failure at review had raised IOP either pre-graft, at rejection or at follow-up. Eyes grafted for herpes simplex keratitis with hypertensive rejection episodes had a higher mean admission IOP, with a more short-lived rise than other eyes.

Adult↗

PubMed1991

The role of penetrating keratoplasty in the management of microbial keratitis.

Penetrating keratoplasty was performed as an emergency procedure in 52 eyes which had perforated from acute microbial keratitis and in a further 11 where perforation had not yet occurred. The results are compared with those of keratoplasty in 33 non-infected perforations and 20 eyes where there had been microbial keratitis which had responded to medical therapy leaving a scarred cornea. This latter group had both a better five year survival (90%) compared to all the others (51%), p less than 0.05, and achieved significantly better visual acuities, p less than 0.005.

Graft Survival↗

PubMed1991

Sphaeropsis subglobosa keratomycosis--first reported case.

Recurrent keratomycosis is reported due to the coelomycete Sphaeropsis subglobosa, which has not been recognised previously as a human pathogen. Infection followed corneal injury by a frayed bamboo cane with implantation of its splinters. Initial successful therapy with 2% clotrimazole topically, to which it was sensitive, was followed by recurrent infection after 39 months, initially a keratitis but progressing to an endophthalmitis. Penetrating keratoplasty was necessary to eradicate the infection. Further isolation of the fungus showed that it had not developed resistance to clotrimazole but had survived dormant, deep in the corneal stroma. S. subglobosa should be considered in bamboo-associated and horticultural injuries.

Aged↗

PubMed1990

The success and survival of repeat corneal grafts.

The results of 99 second grafts in individual eyes are reported. The five-year survival of these grafts was 49%. Allograft rejection was responsible for the majority of failures, but recurrence of host disease and endothelial decompensation were also important. Glaucoma was an important complication in 38% of eyes. Only 12 eyes in the series had no significant complication and 18 eyes achieved a corrected visual acuity of 6/12 or better.

Adolescent↗

PubMed1990

Ocular enlargement following infantile corneal opacification.

Congenital hereditary endothelial dystrophy (CHED) is not generally thought to be associated with other ocular abnormalities. Ultrasonography in a series of twenty eyes (ten patients) with CHED shows ocular enlargement similar to that occurring in uncomplicated axial myopia. There was an inverse relationship between the degree of enlargement and the visual acuity or visual result following penetrating keratoplasty suggesting that infantile corneal oedema sufficient to cause stimulus deprivation may result in abnormal enlargement of the globe.

Adolescent↗

PubMed1990

Microbial keratitis after penetrating keratoplasty.

Thirty cases of microbial keratitis after penetrating keratoplasty were reviewed to examine the associated risk factors, the spectrum of pathogens and the prognosis for graft survival and visual outcome. The indications for keratoplasty in this group differed markedly from those for all corneal grafts performed with a much higher incidence of previous microbial keratitis and of herpes simplex keratitis. A positive culture was obtained in 93% of cases and in contrast to microbial keratitis overall, Gram positive organisms predominated particularly streptococcus pneumoniae and staphylococcus aureus. Risk factors identified were loose or broken sutures, graft decompensation and a poor ocular surface environment. There was a poor prognosis for graft survival with only 23% of cases retaining a clear graft. Overall 53% of cases were regrafted.

Adult↗

PubMed1990

The success of penetrating keratoplasty for keratoconus.

We report the results, over a 20 year period up to 1989, of 201 penetrating keratoplasties in 198 eyes of 158 patients. The five year graft survival was 97%. A corrected visual acuity of 6/12 or better was attained by 91%. The mean spherical equivalent refraction on removal of sutures was -2.68 Ds and the mean cylindrical correction was -5.56 Ds. The cumulative time to dispensing final refractive correction was 38 months for 90% of patients. Rejection episodes occurred in 20% of grafts and were associated with loosening of sutures and bilateral grafts. Atopic patients (28%) were not at greater risk from rejection. Graft refractive surgery was undertaken in 18% and, of these, 55% achieved 6/12 vision or better with an refractive correction which could be dispensed and tolerated within 6 months.

Adolescent↗

PubMed1990

Intraocular surgery following penetrating keratoplasty: the risks and advantages.

Graft survival has been evaluated for patients who underwent subsequent intraocular surgery (extra-capsular cataract surgery or trabeculectomy) between 1983 and 1989. The patients were different from the majority of keratoplasty patients as evidenced by the indications for keratoplasty; corneal perforation was the indication in 24% of cases. Perforated and inflamed eyes were treated aggressively at the time of the acute event, including emergency keratoplasty and intensive topical steroids. Visco-elastic fluids were routinely used during secondary surgery and topical steroids were administered intensively post-operatively. The incidence of post-operative graft rejection was low (less than 14%). Rejection episodes were diagnosed early, prior to the appearance of a Khodadoust line, and were treated aggressively with intensive topical steroids. Glaucoma which was not controlled by topical therapy was surgically managed by trabeculectomy in the first instance. If this failed, tube drainage was performed and long-term topical steroids were administered. The only risk factor identified was uncontrolled glaucoma, P = 0.1. The probability of graft survival (at five years) was 0.83 after cataract surgery and 0.62 after trabeculectomy, but wide confidence limits indicate the difference is not significant.

Cataract↗

PubMed1990

Recurrent macular corneal dystrophy following penetrating keratoplasty.

The recurrence of macular corneal dystrophy within a corneal graft has been described in a number of case reports. In this study, we reviewed 41 transplants in 31 eyes of 16 patients undergoing keratoplasty for macular corneal dystrophy confirmed by histopathological examination. The follow-up time ranged between 25 and 408 months from initial diagnosis. Six eyes of four patients had repeat keratoplasty because of clinical recurrence and visual impairment. Pathological confirmation was available in five of the six eyes. Peripheral clinical recurrence was observed in two more eyes. The size of the graft used was inversely related to the recurrence.

Adult↗

PubMed1989

The changing management and improved prognosis for corneal grafting in herpes simplex keratitis.

Graft survival in a previously reported cohort of patients recruited between 1967 and 1978 (10.6 years' mean follow-up) was reviewed and compared with that for a cohort recruited between 1979 and 1987 (3.8 years' mean follow-up). This allowed analysis of improved graft survival due to changes in management, introduced after critical review of the first group in 1978. The salient changes included transition from intracapsular to extracapsular cataract surgery (P = 0.001) and treatment of rejection episodes with antiviral prophylaxis. Extracapsular cataract surgery improved graft survival (P = 0.07) benefiting inflamed eyes which more frequently required concomitant surgery (P = 0.005). Survival of rejection episodes was improved by antiviral prophylaxis (P = 0.02), and the incidence of recurrent keratitis was reduced (P = 0.0005). The complete and prompt removal of loose sutures improved graft survival (P = 0.025). Long-term survival of first grafts was 70%, and management changes improved overall survival (P = 0.036) despite an increased number of eyes (P = 0.05) grafted when inflamed.

Cataract Extraction↗

PubMed1989

Endocapsular cataract extraction.

Endocapsular (intercapsular) cataract surgery has recently gained popularity, particularly in Europe. We describe our technique of endocapsular cataract extraction and insertion of an intraocular lens and prospectively compare 93 eyes which underwent endocapsular cataract extraction with 83 which underwent a standard extracapsular procedure. There was no apparent difference between the two groups in visual outcome. Preoperative and post-operative complications were more common in the endocapsular group: posterior synechiae formation in the latter occurred in 19%. In 90% of the endocapsular cataract extractions, the lens was placed 'in the bag' at the time of surgery but at three months only 53% remained 'in the bag'. Displacement of one haptic from the capsular bag was associated with symptomatic lens decentration requiring repositioning in four eyes in the endocapsular group and two eyes in the extracapsular group.

Adult↗

PubMed1989

The management of post-keratoplasty glaucoma by trabeculectomy.

The results of 35 consecutive trabeculectomies in eyes developing medically uncontrollable glaucoma following penetrating keratoplasty are presented, with a mean follow-up of 3 years from the time of drainage surgery. Five eyes remained phakic until trabeculectomy was performed. Additional medical therapy was necessary to control the intraocular pressure in 32 eyes, which therefore were considered to have failed to be controlled by trabeculectomy and 90% of these failed within 6 months of filtration surgery. Despite additional medical therapy, in 17 eyes, further drainage surgery was required and 90% of this surgery took place within the first 14 months. Adverse prognostic factors were multiple grafts and synechiae closure of the drainage angle.

Acetazolamide↗