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Biomedical subjects

N S Rice

Publications and source records attributed to N S Rice.

At least 37 records · Page 2Linked to original sources

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↗

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↗

Endophthalmitis caused by exogenous nocardial infection in a patient with Sjögren's syndrome.

A 60-year-old woman receiving prednisolone therapy for Sjögren's syndrome presented with corneal perforation. Therapeutic penetrating keratoplasty was performed, but no causative organism was identified. Focal inflammatory infiltrates in both donor and host cornea and anterior uveitis developed postoperatively. Five months later the inflammation rapidly became much worse, with fulminating abscesses, and the eye was eviscerated because of severe endophthalmitis. Nocardia organisms were identified in the cornea, conjunctiva and vitreous by means of acridine orange and modified Ziehl-Neelsen stains. The infection produced both suppurative and granulomatous inflammation. Reexamination of the penetrating keratoplasty specimen with a modified Ziehl-Neelsen stain revealed a few Nocardia organisms, which suggested that infection had occurred at the time of corneal perforation.

Chloramphenicol↗

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↗

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↗

Macular corneal dystrophy in Iceland.

This study includes the fourteen Icelanders who had penetrating keratoplasty for macular corneal dystrophy during 1974 through 1988, and a further five patients whose deterioration of vision has so far not led to surgery. The clinical presentation, mode of inheritance and the course of the disease were similar to those seen in other studies. The genealogical part of this study indicates that the gene responsible for the disease was already present in Iceland in the 18th century. Though consanguinity, as usually defined, was found to be uncommon, the relatively small pool of genes in the Icelandic population which numbers at present about 250,000 has led to higher prevalence of macular corneal dystrophy than elsewhere. The histopathological findings concur with the conventional description of macular corneal dystrophy, with the exception of two patients with unusually severe photophobia. In these two cases, electron microscopy revealed that the most anteriorly situated deposits were sometimes associated with increased electron-density of small clusters of basal epithelial cells in the overlying epithelium, such cells also being reduced in size and exhibiting few organelles other than swollen mitochondria.

Adolescent↗

Large corneal grafts can be successful.

Seventeen grafts of 10 mm in diameter or larger have been performed on 16 eyes of 15 patients. The major indications for surgery were infections or perforations or both. Follow-up has ranged from 8-54 months (mean 26.4). The 4 year survival probability was 0.64. Although the procedure was successful in saving all but one eye and restored useful vision in the majority, complications including cataract, glaucoma, graft rejection episodes and infections were encountered. The management of these complications is described. At final review, 13 eyes had clear grafts including those in whom regraft had been performed. These results have only been achieved by close co-operation between patients and the medical team responsible for their care.

Adolescent↗

The use of silicone drainage tubing to control post-keratoplasty glaucoma.

A series of 20 patients who developed severe post-keratoplasty glaucoma unresponsive to medical therapy and trabeculecetomy were treated using silicone drainage tubing and an anterior encircling gutter. The results indicate a four year probability of maintaining vision and normal intraocular pressure (less than 21 mmHg) of 0.68. In contrast, an earlier series of 13 patients receiving cycloablation with cryotherapy did significantly worse.

Anastomosis, Surgical↗

Longterm prognosis for corneal grafting in herpes simplex keratitis.

A previously reported cohort of patients was reviewed after mean follow-up of 10.9 years. The overall probability of survival was 45%, but first grafts had a greater probability of survival than second (P = 0.12) or further (P = 0.19) grafts. Preoperative active keratitis adversely affected survival (P = 0.123). The major cause of failure was graft rejection. Regrafts were more likely to fail from rejection episodes (P = 0.0005). Antiviral prophylaxis improved the outcome for rejection (P = 0.005) and reduced the incidence of HSK recurrence complicating rejection. Suppurative keratitis occurred in 12.4% of grafts as a complication of epitheliopathy including HSK recurrence. The outcome in these cases was particularly poor. Loose continuous graft sutures resulted in graft failure in 10.6% of grafts which may be improved by using interrupted suturing. Our results suggest the longterm prognosis for grafting in herpes simplex keratitis are not as good as may have been predicted from previous analyses.

Cornea↗

Congenital hereditary corneal oedema of Maumenee: its clinical features, management, and pathology.

The clinical and histological features of congenital hereditary corneal oedema in 23 patients are presented. The series includes cases of both recessive and dominant inheritance. Although the condition is present at birth or in early childhood, visual development appears to be little impaired, if at all. Penetrating keratoplasty carries a relatively good surgical prognosis and can produce a substantial visual gain even when carried out late in life.

Adolescent↗

Partial galactose disorders in families with premature cataracts.

Minor and major deficiencies of enzymes affecting galactose metabolism may be associated with cataracts of early onset. Results are presented for 10 such families with minor enzymatic disorders. Expression of the major disorders probably involves galactitol accumulation and osmotic lens damage but this mechanism is not obviously associated with minor disorders. The observed incidence of minor incomplete enzymatic disorders of galactose metabolism in families with an incidence of cataracts of early onset may be at least partly incidental.

Adolescent↗

Corneal graft rejection: a new rabbit model and cyclosporin-A.

In order to test the efficacy of topically applied cyclosporin-A in preventing corneal allograft rejection, existing rabbit models were modified to produce a new model in which the allograft reaction could be consistently initiated solely as a result of corneal transfer without any additional means of sensitisation. With this model, which reflects clinical corneal grafting more closely than many previous models, cyclosporin-A 1% drops applied to the recipient eye 5 times daily for 4 weeks inhibited corneal graft rejection. When cyclosporin-A 1% drops were applied to corneal allografts for 13 weeks, 44% of grafts remained clear 180 days after transplantation. No side effects were observed that could be attributed to topically applied cyclosporin-A.

Animals↗