No abstract

SummaryThirty 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 kera titis and of herpes simplex keratitis.A positive culture was obtained in 93% of cases and in contrast to microbial kera titis overall, Gram positive organisms predominated particularly streptococcus pneumoniae and staphlycoccus 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. A positive culture was defined as growth of more than one colony of an organism in the inoculating streak of any culture medium.In most cases multiple colonies were grown. Culture media routinely used were blood agar, Sabouraud's medium, thioglycol late medium, nutrient broths and where indi cated Eschrichia Coli seeded non-nutrient agar for Acanthamoeba.

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.