Penetrating keratoplasty for pseudophakic corneal oedema.

AIMS: The study was designed to investigate the results of penetrating keratoplasty (PK) for pseudophakic corneal oedema (PCO). METHODS: Retrospective analysis of 80 consecutive patients (82 eyes) who underwent PK for PCO between the years 1980-1992 with a minimum follow up of 12 months. RESULTS: PKs for PCO have accounted for as many as 20% of all grafts performed in the hospital in recent years. The interval between cataract extraction and PK ranged from 6 to 161 months (mean 51 months). The intraocular lens was removed in 45 (55%), left in situ in 30 (37%), and exchanged in seven (8%) of cases respectively. Of the intraocular lenses involved 62% were iris supported, 31% angle supported, and 7% were posterior chamber lenses. Actuarial analysis shows graft survival to be 91% at 1 year and 86% at 2 years after surgery. The likelihood of graft survival was significantly enhanced by removal of the intraocular lens (p < 0.01). A corrected Snellen visual acuity worse than 6/60 was present in 36% of patients with a clear corneal graft. Ocular comfort was achieved in all patients with a clear corneal graft. CONCLUSION: PK for PCO resulted in a disappointing visual result in a large proportion of patients. PK was, however, successful in relieving pain and corneal ulceration when present.

Preoperative ultrasound biomicroscopy to assess ease of haptic removal before penetrating keratoplasty combined with lens exchange.

PURPOSE: To evaluate a method of assessing anterior chamber intraocular lens (IOL) haptics before combined penetrating keratoplasty and IOL exchange in eyes with poor corneal clarity resulting from pseudophakic bullous keratopathy (PBK). SETTING: Department of Ophthalmology, Toronto Hospital, Ontario, Canada. METHODS: Twelve eyes (25 haptics) with PBK were studied using ultrasound biomicroscopy (UBM). The degree of haptic encasement was graded. The result was compared with the degree of difficulty and the complications encountered in removing the IOL at the time of surgery. The surgeons were masked as to the UBM results. RESULTS: All haptics were easily visualized with UBM, with 23 in the angle and 2 passing through a peripheral iridectomy. On UBM, 9 haptics were noted to lie free in the angle, and 16 were encased by fibrotic tissue. Eight were covered by less than 100 microns and 8 by more than 100 microns of tissue. Calculations using Kappa statistics found a strong predictive value for the UBM in identifying the presence or absence of fibrotic encasement and degree of difficulty in removing the anterior chamber IOL haptics. Ultrasound biomicroscopy also allowed assessment of the adjacent angle for synechias. CONCLUSION: Ultrasound biomicroscopy provides an alternative method for evaluating anterior chamber IOL haptics when gonioscopy is not possible because of corneal opacity. This method allows the surgeon to predict preoperatively the degree of difficulty that will be encountered in explanting the IOL.

Disposable soft contact lens ulcers: a study of 43 cases seen at Manchester Royal Eye Hospital.

We report an outbreak of 43 episodes of presumed microbial keratitis in 42 disposable soft contact lens wearers seen in the Accident Room of Manchester Royal Eye Hospital during a period of 20 months, and compare this with the general incidence of contact lens-related corneal infection found in a retrospective survey of 6 months' Accident Room attendances during the same period. Thirty-seven patients had worn Acuvue lenses, three had worn Nuvue, and there was no record in two cases. Corneal scrapes were taken for microbiological examination in 27 patients, and 6 of these were culture positive. Conjunctival swabs were taken from eight eyes and one was culture positive. The contact lenses of 11 patients were sent for culture and all grew pathogenic organisms. Pseudomonas spp. were the most common organisms grown, having been found in three of six corneal scrapes and six of 11 contact lens cultures. All affected eyes responded promptly to cessation of contact lens wear and topical antibiotic therapy, with none sustaining severe or permanent visual loss. Reasons for the associated high risk of microbial keratitis are discussed. Thirty-three of the 42 patients responded to a questionnaire regarding lens wear and care and their responses are reported. In consequence, we consider disposable soft contact lenses to be relatively high-risk devices for the cosmetic management of simple myopia, and their continued use must be called into question.

Microphthalmos with cyst in monozygous twins.

We present two cases of microphthalmos with cyst affecting monozygotic twins. The etiology and pathogenesis of this developmental anomaly are discussed. The diagnostic evaluation, differential diagnoses, and management options of this unique disorder are also considered.

General practitioner referrals to an eye hospital: a standard referral form.

To assess general practitioner (GP) referrals to an eye hospital, 500 consecutive referral letters were analysed for content, diagnosis, ocular examination, and medical and drug history. Inadequate information was provided. Visual acuity was measured by general practitioners in only 3.7% of referrals. The standard of ocular examination compared unfavourably with that of ophthalmic opticians. A standard ophthalmic referral form is proposed, and referral protocols are desirable. Undergraduate education in ophthalmology is inadequate and requires more curricular time.

Evaluation of the long-term rotational stability of single-piece, acrylic intraocular lenses.

OBJECTIVES: To assess rotational stability beyond 3 months and compare the different designs and materials of two acrylic intraocular lenses (Akreos Adapt (Bausch & Lomb, Rochester, New York, USA) and AcrySof SA60AT (Alcon, Fort Worth, Texas, USA)). METHODS: Post hoc analysis of retro-illumination images from a previous multicentre, contralateral eye study was used to assess intraocular lens (IOL) position and rotational stability for up to 24 months postoperatively. The image of IOL and capsular bag enabled any rotation to be calculated by measuring the angle from the horizontal to an arbitrary point on the IOL edge. The difference between the angle at the first and subsequent visits was subtracted to give a measure of IOL rotational stability. RESULTS: Data were collected from 64 eyes fitted with the Akreos IOL and 58 eyes fitted with the AcrySof IOL. Mean (SD) absolute rotation values for the two IOLs were small over the 2-year period, ranging from 2.53 degrees (2.40 degrees) to 3.2 degrees (2.57 degrees) with Akreos Adapt and 2.67 degrees (2.22 degrees) to 3.33 degrees (3.06 degrees) with AcrySof SA60AT at 6 and 24 months, respectively. The differences were not statistically significant. Using the ANSI draft toric IOL standard, the percentage of lenses rotating < or =5 degrees was 90% at 6 months, 91% at 12 months and 80% at 24 months for the Akreos lens and 89% at 6 months, 75% at 12 months and 81% at 24 months for the AcrySof lens. CONCLUSION: Spherical, single-vision acrylic IOLs continue to show some tendency to rotate for up to 24 months postoperatively, although this is usually small. The Akreos Adapt lens may be a good platform for a toric lens product.

Diplopia following head injury.

Two cases of traumatic fourth cranial nerve palsy are described. The treatment is discussed.

Three wall orbital decompression for Graves' ophthalmopathy via a coronal approach.

Ten patients with dysthyroid eye disease who underwent a three wall orbital decompression procedure performed via a coronal approach were reviewed. The indications, results, complications and surgical techniques involved in this surgery are discussed. We believe that this approach offers a number of advantages over other techniques and has a role in the management of carefully selected patients with dysthyroid eye disease who have severe unilateral or bilateral proptosis, with or without dysthyroid optic neuropathy.

The 'baseball' orbital implant: a prospective study.

The 'baseball' orbital implant was described by Frueh and Felker in 1976. Although this implant was originally described for use as a secondary implant, it has also been widely used as a primary implant at the time of enucleation. This prospective study evaluated the effectiveness of this implant used both primarily and secondarily. Forty-four patients were implanted between April 1990 and May 1991, 19 of the implants being primary and 25 secondary. A standardised operative and post-operative protocol was followed. The mean follow-up time was 31 months (range 24-36 months). The patients were evaluated for the degree of volume replacement, implant and associated prosthesis motility, secondary eyelid and socket problems, patient satisfaction, the need for further surgery and post-operative complications. The overall results achieved by primary implantation were superior to those of secondary implantation. Our results suggest that this implant provides a satisfactory functional and cosmetic rehabilitation of the anophthalmic patient with few complications.

Assessment of the diurnal variation in central corneal thickness and intraocular pressure for patients with suspected glaucoma.

OBJECTIVE: To assess whether a single daily measurement using ultrasonic pachymetry gives a representative assessment of mean central corneal thickness (CCT) in patients with suspected glaucoma and whether diurnal changes in CCT are related to diurnal variations in intraocular pressure (IOP). DESIGN: Cross-sectional study. METHOD: Central CCT and IOP were measured by a single observer in 56 eyes of 28 patients with suspected glaucoma using an ultrasonic pachymeter and a Goldmann tonometer. Four measurements were made over a 24-hour period: at 8:00 AM, 12:00 PM, 4:00 PM, and 8:00 PM. MAIN OUTCOME MEASURES: Intraocular pressure and pachymetry. RESULTS: Mean IOP was 19.80 mmHg at 8:00 AM (95% confidence interval [CI], 18.95-20.66 mmHg), 20.38 mmHg at 12:00 PM (95% CI, 19.49-21.26 mmHg), 19.91 mmHg at 4:00 PM (95% CI, 19.99-21.83 mmHg), and 19.23 mmHg at 8:00 PM (95% CI, 18.35-20.11 mmHg). Mean CCT was 569.4 microm (95% CI, 560.2-578.7 microm), 567.6 microm (95% CI, 558.4-576.7 microm), 569.1 microm (95% CI, 559.5-578.6 microm), and 567.2 microm (95% CI, 557.9-576.4 microm) at the four respective time points. There was no significant correlation between IOP and CCT in any patient (Pearson rank correlation coefficient); nor was there any significant correlation between the mean diurnal variations of IOP and CCT. CONCLUSIONS: In this group of patients with suspected glaucoma, there was no significant variation in CCT. Therefore, a single measurement of CCT is sufficient when assessing patients with suspected glaucoma. There was no correlation between change of IOP and change of CCT.

Relationship between corneal thickness and measured intraocular pressure in a general ophthalmology clinic.

OBJECTIVE: To assess whether central corneal thickness (CCT) is a confounding factor in the classification of patients attending for glaucoma assessment in a district general hospital. DESIGN: Cross-sectional study by a single observer. PARTICIPANTS: Patients attending a general ophthalmic clinic: 235 clinically normal eyes, 52 eyes with normal-tension glaucoma (NTG), 335 eyes with primary open-angle glaucoma (POAG), 12 eyes with pseudoexfoliative glaucoma (PXE), 42 eyes with chronic angle closure glaucoma (CACG), and 232 glaucoma suspect (GS) eyes. INTERVENTION: Central corneal thickness was measured using ultrasonic pachymetry. MAIN OUTCOME MEASURE: Correlation of CCT and diagnosis. RESULTS: Mean CCT was 553.9 microm (95% confidence intervals [CI] for the mean, 549.0-558.8 microm) in the clinically normal eyes, 550.1 microm (95% CI, 546.6-553.7 microm) in the POAG eyes, 514.0 microm (95% CI, 504.8-523.3 microm) in the NTG eyes, 530.7 microm (95% CI, 511.2-550.1 microm) in the PXE eyes, 559.9 microm (95% CI, 546.8-573.0 microm) in the CACG eyes, and 579.5 microm (95% CI, 574.8-584.1 microm) in the GS eyes. The differences of mean CCT between the groups were highly significant (P< 0.001 analysis of variance). Eighty-five percent of eyes with NTG and only 36% of eyes with POAG had a mean CCT of 540 microm or less. Thirteen percent of eyes with POAG and 42% of GS eyes had a mean CCT greater than 585 microm. CONCLUSIONS: The CCT measurement is desirable in patients attending for glaucoma assessment in a district general hospital to avoid misclassification resulting from the relationship between CCT and tonometric pressure. Central corneal thickness alone is not an accurate predictor for the clinical diagnosis in this group of eyes. However, many eyes diagnosed as having NTG have thin corneas, which would tend to lower the tonometrically recorded intraocular pressure (IOP), so the finding of a less-than-normal thickness cornea introduces some doubt as to the diagnosis of NTG. For the GS eyes, most eyes had thick corneas, which would tend to increase the tonometrically recorded IOP. Thus, GS eyes with modest elevation of IOP and a thick cornea may be at low risk of progressing to POAG. Thus, many patients with "high IOPs" and a thick CCT do not necessarily have high IOPs and may not need to be followed as GS eyes.