A. D. M. Steele

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.

Conjunctival autografting in the surgical management of pterygium.

In a retrospective survey of 117 operations for primary or recurrent pterygium, conjunctival autografting was compared with both excision without conjunctival closure (‘bare sciera excision’) and excision with complete conjunctival closure. The probability of corneal recurrence at 36 months after surgery was determined by survival curve analysis. In previously unoperated cases conjunctival autografting (n = 15) resulted in a 14% probability of recurrence, compared with 70% for bare sciera excision (n = 50) and 69% for excision with complete conjunctival closure (n = 20). In previously operated cases conjunctival autografting (n = 17) resulted in a 7% probability of recurrence, compared with 82% for bare sciera excision (n = 15). Hazard ratio analysis confirmed the statistical significance of these results at the 95% confidence level. Conjunctival autografting was more likely to produce an improvement in visual acuity than other forms of surgery.

Granular Corneal Dystrophy: Visual Results and Pattern of Recurrence after Lamellar or Penetrating Keratoplasty

BACKGROUND Granular corneal dystrophy is a rare indication for corneal transplantation. Both penetrating and lamellar keratoplasty have been recommended, but because granular corneal dystrophy is known to recur within the donor material and multiple grafts may be necessary, the best surgical option has not been clearly established. The cellular cause of the dystrophy is unknown and the authors hypothesized that the rate and pattern of recurrence within lamellar and penetrating grafts might give clues to its etiology. METHODS The authors compared the visual outcome, rate, and pattern of recurrence after 20 penetrating keratoplasties and 11 lamellar keratoplasties for granular corneal dystrophy. RESULTS Penetrating keratoplasty and lamellar keratoplasty have a good visual outcome in granular corneal dystrophy. Visual acuities after both procedures were not statistically different. Recurrence of the dystrophy within the graft material was almost universal within 4 years. It first appeared centrally and superficially, occasionally adopting a vortex pattern suggesting epithelial involvement. The recurrence-free interval was independent of size and type of graft performed. CONCLUSION The authors recommend lamellar keratoplasty as a primary procedure in managing visually disabling granular corneal dystrophy if the deposits are limited to the superficial cornea. This is particularly applicable in younger patients in whom multiple procedures may be necessary over a lifetime due to recurrence of the dystrophy, and the lower morbidity rate associated with lamellar keratoplasty becomes appreciable. Although granular corneal dystrophy generally is classified as a stromal dystrophy, the pattern of recurrence is more consistent with an epithelial or tear-borne abnormality than a disease of the stromal keratocyte.

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.

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 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.

Longterm prognosis for corneal grafting in herpes simplex keratitis

A previously reported cohort of patients4 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.

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 synechial closure of the drainage angle.

Excimer laser photorefractive keratectomy for myopia: 12 month follow-up

A prospective study of excimer laser photorefractive keratectomy was performed with the aim of correcting a range of myopic errors between −1.00 and −10.00 dioptres. Corneal healing was monitored through the first post-operative year by serial assessments of refraction, contrast sensitivity, corneal haze, pachymetry and keratometry. Eighty-one patients were recruited for the study. At 12 months 81% were within ± 1.00 dioptre of desired emmetropia and with unaided vision of 6/12. Contrast sensitivity was found by Pelli–Robson assessment to be reduced throughout the 12 months and regression analysis predicted recovery by 2 years. At 12 months, however, only 15% of patients were found to have lost a single line of best corrected Snellen acuity. Predictability of results was found to be greatest for initial errors less than −4.00 dioptres. No serious complications were observed during the follow-up period, but refraction had not stabilised in all cases and patients remain under review.

Repair of Descemet's membrane detachment after intraocular surgery

Abstract We repaired three unselected cases of Descemet’s membrane detachment. A visually successful outcome was achieved in one case, an anatomically successful outcome in another, and no improvement in the last. We believe that large detachments should be repaired early rather than waiting for possible spontaneous reattachment, and we advocate sulfur hexafluoride fluid‐gas exchange as the procedure of choice.

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.