Characteristics of and risk factors for contact lens-related microbial keratitis in a tertiary referral hospital.

AIM: A retrospective case-control study was conducted at a tertiary referral hospital to determine the characteristics of and risk factors for contact lens (CL) related presumed microbial keratitis. METHODS: Two hundred and ninety-one cases of presumed microbial keratitis were retrospectively identified over a 2-year period. Records were reviewed for a history of CL wear and, where identified, CL, demographic, and clinical data were collected. Lens wearing controls (n=186) were identified by a community telephone survey. Multiple logistic regression estimated risk factors for infection and vision loss. RESULTS: Ninety-nine (34%) new cases of presumed microbial keratitis were associated with CL wear. Overnight soft CL use was associated with an increased risk of infection compared to daily disposable CL wear (odds ratio (OR): 8.03, 95% confidence interval (CI): 1.82-35.46). Compared with older CL wearers, 15-24 year olds had a 3.5 times greater risk of infection (OR, 95% CI: 1.7-7.4). Of the 84 cases with available data, 24 (29%) lost two or more lines of best-corrected visual acuity. Delaying treatment by 49-72 h had a 4.5 times (OR, 95% CI: 1.4-14.9) greater risk of visual loss compared to seeking treatment early. Of the 99 cases of infection, 88 were scraped and 78% (69/88) of these returned a positive culture. Gram-positive bacteria were the predominant causative organisms. CONCLUSION: Overnight use of CL and youth carry a greater risk of infection. Practitioners should reinforce the importance of proper CL care at all times, and early presentation following the onset of symptoms.

Corneal replacement using a synthetic hydrogel cornea, AlphaCor: device, preliminary outcomes and complications.

PURPOSE: Clinical assessment of outcome of corneal replacement with a synthetic cornea, AlphaCor, in patients considered at too high risk for conventional penetrating keratoplasty with donor tissue to be successful, but excluding indications such as end-stage dry eye that might be suited to traditional prosthokeratoplasty. METHODS: All patients in the multicentre clinical trial were managed according to an approved protocol, with Ethics Committee approval in each centre. Preoperative visual acuity ranged from perception of light (PL) to 6/60 (20/200). Implantation was by means of an intralamellar technique, with a conjunctival flap in most cases. Tissues anterior to the optic were removed as a secondary procedure. RESULTS: Up to 30 November 2001, 40 AlphaCor devices had been implanted in 38 patients, of mean age 60 years. Follow-up ranged from 0.5 months to 3 years. There had been one extrusion (2.5%) and four cases (10%) where a device had been removed due to melt-related complications. All five of these cases received a donor corneal graft after the device was removed, with these grafts remaining anatomically satisfactory and epithelialised to date. Corneal melts in AlphaCor recipients were found to be strongly associated with a history of ocular herpes simplex infection. Two further devices (5%) were removed owing to reduced optic clarity after presumed drug-related deposition, and have been successfully replaced with second devices. Mean preoperative best-corrected visual acuity was hand movements. Visual acuities after surgery ranged from PL to 6/6(-2) (20/20(-2)). CONCLUSIONS: Early results suggest that the AlphaCor, previously known as the Chirila keratoprosthesis (Chirila KPro), has a low incidence of the complications traditionally associated with keratoprostheses and can be effective in restoring vision in patients considered untreatable by conventional corneal transplantation. Importantly, the device can be replaced with a donor graft in the event of development of a significant complication. A history of ocular herpes simplex is a contraindication to AlphaCor implantation. Ongoing monitoring of clinical outcomes in all patients will allow the indications for AlphaCor, as opposed to donor grafts, to be determined.

Atypical presentation of Acanthamoeba keratitis.

PURPOSE: To present two cases of minimal pain Acanthamoeba keratitis to alert clinicians to remember Acanthamoeba when evaluating atypical cases of keratitis. METHODS: The histories of two cases were reviewed with attention to clinical presentation subjective complaints, treatment, and long-term outcome. RESULTS: In case 1, a 24-year-old man presented with decreased vision and an irritated feeling in his eye. He did not wear contact lenses. His initial diagnosis was adenoviral conjunctivitis. One month later, he was diagnosed with atypical herpes simplex keratitis and started on acyclovir. Two weeks later, he was referred to the Cornea Service. Further history revealed the patient to be a professional triathlete who trained by swimming in a fresh water pond. He was found to have an unusually high pain tolerance. Biopsy revealed Acanthamoeba. He was admitted for intensive therapy with neomycin, propamidine isethionate, and polyhexamethylene biguanide. Two years after diagnosis, he has best-corrected visual acuity of 20/100. In case 2, a 28-year-old man with known herpes simplex keratitis presented with decreased vision. He was started on topical trifluridine. After 6 weeks without improvement, he was referred for corneal evaluation. His eye always remained comfortable. Corneal sensation was markedly decreased. Further history revealed that he swam in fresh water. Biopsy was positive for Acanthamoeba. After 1 year of therapy with polyhexamethylene biguanide and neomycin, visual acuity was 20/200, and the patient underwent a corneal transplant. CONCLUSION: Acanthamoeba keratitis must be considered in the differential diagnosis of keratitis, even without the classic presentation of severe pain and predisposing corneal trauma, including contact lens wear.

A comparison of different depth ablations in the treatment of painful bullous keratopathy with phototherapeutic keratectomy.

AIM: To study the efficacy of phototherapeutic keratectomy (PTK) for pain relief for patients with painful bullous keratopathy and poor visual potential. METHODS: Patients with painful bullous keratopathy and poor visual potential were treated with superficial PTK (8-25 microm), intermediate (50-100 microm) or deep PTK (25% stromal thickness) using the Nidek EC5000 excimer laser after manual epithelial debridement. Follow up ranged from 1 to 24 months (mean 6.5 months). Outcome measures included symptomatic relief and need for further treatment. RESULTS: In the superficial PTK group five of eight (62%) patients improved symptomatically after treatment. The three (38%) who did not improve went on to have penetrating keratoplasty for pain relief. In the intermediate depth group only two of five (40%) patients had symptom alleviation. The three others (60%) required further procedures. 20 of 24 (83%) patients treated with deep PTK had significant or total alleviation of symptoms. Of these, one developed acute anterior uveitis 9 months after PTK and two required botulinum ptosis for persistent corneal epithelial defects, one of whom had three consecutive episodes of microbial keratitis. Three of 24 suffered occasional discomfort and one patient required a penetrating keratoplasty for continued pain. CONCLUSION: PTK can be a useful therapeutic measure in painful bullous keratopathy with poor visual potential. Deep PTK appears to be more successful in pain management than superficial treatment.

Evaluation of the myocilin (MYOC) glaucoma gene in monkey and human steroid-induced ocular hypertension.

PURPOSE: Glucocorticoid-induced ocular hypertension (the steroid response) may result in optic nerve damage that very closely mimics the pathologic course of primary open angle glaucoma (POAG). In addition, patients with glaucoma and their relatives are much more likely to exhibit the steroid response than unaffected individuals, suggesting a potential link between the steroid response and POAG. Recently, the expression of a gene (MYOC) in the trabecular meshwork was shown to be steroid-induced. MYOC variations thought to be disease-causing also were found in 3% to 5% of POAG cases. The purpose of this study was to determine whether some variations in MYOC might be involved in steroid-induced ocular hypertension. METHODS: Seventy human steroid responders and 114 control subjects were screened for variations in the coding sequence and promoter of MYOC. Also, topical doses of dexamethasone (DEX) were administered to cynomolgus monkeys to determine their steroid responsiveness, and the MYOC orthologue was cloned from the cynomolgus monkey. RESULTS: Overall, 109 instances of 20 different sequence variations were identified in the human myocilin gene. However, only four of these (each observed in a single individual) met the study criteria for a possible phenotype-altering variation. Three of these were present in steroid responders and one in a control patient, a distribution that was not statistically significant (P: = 0.3). In addition, the allele frequency of a closely flanking marker was compared between the steroid responders and the control subjects, and no evidence for linkage disequilibrium was observed. Reproducible and reversible ocular hypertension was induced in approximately 40% of the monkeys treated with DEX, similar to that seen in man. Ten monkeys were screened for MYOC mutations with single-strand conformation polymorphism (SSCP) analysis. Overall, 37 instances of 13 different sequence variations were observed. Four of these changes met the study criteria for a possible phenotype-altering variation, and these were equally distributed between responder and nonresponder monkeys. CONCLUSIONS: This study identified no statistically significant evidence for a link between MYOC mutations and steroid-induced ocular hypertension.

Management of alkali burns : an 11-year retrospective review.

OBJECTIVE: To review the spectrum of patients with alkali burns admitted over an 11-year period and to assess the clinical outcomes after the introduction of a standard alkali burn treatment protocol. DESIGN: Retrospective nonrandomized comparative study. PATIENTS AND INTERVENTIONS: A total of 121 patient records with alkali burns (n = 177 eyes) admitted to a tertiary hospital between 1987 and 1998 were reviewed. Eyes treated with a standard alkali burn treatment protocol, which included intensive topical steroids, ascorbate, citrate, and antibiotics, were compared with eyes treated by conservative management with antibiotics, and a short course of steroids. MAIN OUTCOME MEASURES: Time to corneal reepithelialization, final best-corrected visual acuity, and time to visual recovery, length of hospital stay, and complications were analyzed. RESULTS: The standard protocol tended to delay corneal reepithelialization by one day (P: = not significant) in eyes with grade 1 burns (n = 76) and by 2 days (P: = 0.04) in grade 2 burns (n = 52), with no difference in final visual outcome. There were 37 eyes with grade 3 burns. Those treated with the standard protocol showed a trend toward more rapid corneal reepithelialization. Twenty-seven of 29 (93%) eyes with grade 3 injuries achieved a final best-corrected visual acuity of 20/40 or better compared with 3 of 6 (50%) eyes not treated according to the standard protocol (P: = 0.02). Eyes with grade 4 burns (n = 12), whether treated with the standard protocol or not, required 10 to 12 weeks for corneal reepithelialization. There was no statistically significant difference in final visual acuity. CONCLUSIONS: On the basis of our findings, a number of recommendations can be made for the management of alkali injuries. Patients with a grade 1 or 2 injury do not require routine admission and do not benefit from the use of intensive treatment with ascorbate and citrate. A trend toward more rapid healing and a better final visual outcome were apparent in grade 3 burns, but our standard protocol made no difference in grade 4 burns.

Pterygium surgery in Victoria: a survey of ophthalmologists.

AIM: To determine the surgical approaches and adjunctive therapy es currently used by Victorian ophthalmologists for the treatment of primary and recurrent pterygia. METHOD: Ophthalmologists practising in Victoria were asked to complete a written survey relating to their experience with pterygium surgery. RESULTS: Responses were received from 142 of 165 ophthalmologists surveyed (86%). Of these, 107 (75%) had performed at least one pterygium operation during the preceding 2 years. Excision followed by beta irradiation was the most commonly performed procedure for both primary (57%) and recurrent (35%) pterygia. The next most commonly performed procedure for primary pterygia was excision leaving bare sclera (15%) and, for recurrent pterygia, excision with autologous conjunctival transplantation (26%). Considerable variation was observed in surgical technique, choice of adjunctive therapy, postoperative care and in the surgeons' estimates of the frequency of major complications. CONCLUSION: Although there is little consensus regarding the surgical management of pterygium, beta irradiation remains the most commonly used adjunctive therapy in Victoria.

Pyogenic granuloma of the cornea.

BACKGROUND: Ocular pyogenic granulomata are uncommon and are often associated with a chalazion or previous ocular and adnexal surgery The avascular nature of the cornea may explain the rarity of pyogenic granulomata at this site. We report on a case of corneal pyogenic granuloma following previous corneal surgery. METHODS: Ophthalmologists who had treated the patient previously were contacted and earlier clinical notes and histopathological examinations were reviewed. The clinical course following excision of the pyogenic granuloma is described, as are the histopathological findings. RESULTS: Histological examination confirmed the diagnosis of pyogenic granuloma. Excision was followed by a clinical recurrence at a different site with spontaneous resolution. CONCLUSIONS: Pyogenic granulomata of the cornea are rare. However, the present case illustrates the importance of considering benign inflammatory causes in the differential diagnosis of a corneal mass lesion so as to avoid unnecessarily aggressive intervention. To our knowledge, spontaneous resolution of a corneal pyogenic granuloma has not been previously described.

Delayed microbial keratitis following radial keratotomy.

BACKGROUND: We report on the case of a 46-year-old female who presented with delayed microbial keratitis 10 years after uncomplicated radial keratotomy. METHODS: The pre- and postoperative clinical record was reviewed following her presentation to the Corneal Clinic. Slit-lamp examination revealed a stromal inflammatory infiltrate at the site of an earlier radial keratotomy incision. The lesion was scraped and a coagulase-negative Staphylococcus aureus was cultured in enrichment broth. RESULTS: The keratitis was treated successfully with combination fortified topical antibiotics without loss of vision. CONCLUSIONS: Although microbial keratitis is a well documented complication of incisional refractive procedures, it is rarely encountered as late as one decade after surgery. Patients should be warned of this possibility and the need for prompt treatment.

Corneal and conjunctival infections.

Recent advances in the field of infectious conjunctivitis and keratitis include new diagnostic methods, the identification of new pathogens, and novel therapeutic agents. Tandem confocal microscopy has been used to diagnose Acanthamoeba keratitis, and polymerase chain reaction has proven to be a rapid and sensitive technique for detecting specific viral antigens, particularly in cases where cultures yield no growth. Two new antiviral agents, ganciclovir and carbocyclic oxetanocin G, have been shown to be as effective as acyclovir in treating herpetic epithelial disease. The fluoroquinolones, especially ofloxacin, have become the antimicrobial agents of choice in the initial management of selected cases of bacterial keratitis.

Late recurrences and the necessity for long-term follow-up in corneal and conjunctival intraepithelial neoplasia.

PURPOSE: The purpose of the study was to elucidate the natural history of corneal-conjunctival intraepithelial neoplasia (CIN) and suggest treatment and follow-up guidelines. METHODS: The records of all histologically proven cases of CIN at the Royal Victorian Eye and Ear Hospital between 1979 and 1994 were reviewed. RESULTS: Seventy-nine eyes of 76 patients had a pathologic diagnosis of CIN and were observed for up to 15 years. The lesion recurred in 31 eyes (39%) overall. There was no statistical difference shown in the likelihood of recurrence based on histologic classification. Complete excision was attempted in each case. In 18 eyes, dysplastic cells were evident at the excision margin. Ten (56%) of these tumors recurred, compared to a 33% recurrence rate in completely excised lesions. The time to the first recurrence ranged from 33.0 days to 11.5 years between the first and second surgeries, with 11 lesions recurring after more than 4 years. Incompletely excised lesions reappeared more rapidly (average, 2.5 years) than did those with clear surgical margins (average, 3.8 years). Seven cases progressed to invasive squamous cell carcinoma and four cases led to blindness or removal of the eye. CONCLUSIONS: This study suggests that excision margin at the time of surgery is the most important factor in predicting recurrence. The slow growth of the recurrent lesions combined with the ever-present malignant potential leads the authors to suggest that all patients with a history of CIN warrant annual follow-up for the remainder of their lives.

Association of keratoconus with granular corneal dystrophy.

A 23-year-old woman presented with a history of reduced vision and foreign body sensation in both her eyes. Ocular examination revealed the simultaneous presence of bilateral keratoconus and granular corneal dystrophy. To our knowledge, bilateral concurrent occurrence of keratoconus and typical granular corneal dystrophy has not been reported previously. In such a case, penetrating keratoplasty performed for keratoconus may also carry the risk of recurrence of the granular dystrophy.

Retreatment after excimer laser photorefractive keratectomy. The Melbourne Excimer Laser Group.

PURPOSE: To determine the risk factors for undercorrection of myopia after photorefractive keratectomy and to evaluate the efficacy and safety of retreatment. METHODS: A VISX Twenty/Twenty excimer laser was used to treat myopia and myopic astigmatism of up to -15.00 diopters (spherical equivalent) at the corneal plane. Retreatments were performed primarily for undercorrection with or without coexistent corneal haze or abnormalities on videokeratoscopy. Not every patient who was undercorrected requested retreatment. RESULTS: Of 645 eyes (440 patients) followed up for more than 12 months, 58 eyes (9%) required retreatment. The retreatment rate increased with increasing myopia: 17 (5%) eyes with myopia of less than -5.00 diopters, 30 (13%) eyes with myopia of -5.01 to -10.00 diopters, and 11 (19%) eyes with myopia of greater than -10.00 diopters required a second procedure. A higher retreatment rate was observed after astigmatic corrections than after spherical corrections. Corneal haze after retreatment was no greater than that observed after initial procedures. Twelve months after primary procedures, 378 (75%) of 504 eyes were within 1.00 diopter of emmetropia, whereas 27 (69%) of 39 eyes attained this result after retreatment. A total of 383 (76%) of 504 eyes attained uncorrected visual acuity of 20/40 or better after primary procedures, compared with 25 (64%) of 39 eyes after retreatment. CONCLUSIONS: The risk of undercorrection requiring retreatment after photorefractive keratectomy increases with the magnitude of the primary treatment. Although less successful than initial procedures, retreatment appears to enhance the results of photorefractive keratectomy.

Absence of effect of simvastatin on the progression of lens opacities in a randomised placebo controlled study. Oxford Cholesterol Study Group.

AIMS: A detailed assessment of ophthalmic effects of an HMG CoA reductase inhibitor, simvastatin, was performed. METHODS: Six hundred and twenty one individuals considered to be at increased risk of coronary heart disease were randomised, following an 8 week placebo 'run in' period, to receive 40 mg daily simvastatin, 20 mg daily simvastatin, or matching placebo. Patients with a baseline corrected visual acuity better than 6/24 and without a history of cataract were eligible for detailed ophthalmic assessment at 6 months (539 patients assessed) and at 18 months (474 patients assessed). RESULTS: No significant differences between the treatment groups were detected at the 6 month or 18 month visit in the refractive condition of the eye or in the mean intraocular pressure. Nor were there clear differences in the Oxford grading system scores for various measures of the major types of cataract (cortical spokes, posterior subcapsular cataract, nuclear brunescence, white scatter) or for other morphological features visible within the lens (fibre folds or focal dots). Scheimpflug slit image photographs and retroillumination analysis of the percentage of cataract within a defined region of the lens were also performed at each visit, with no clear differences observed between the treatment groups. CONCLUSION: This single centre double blind study found no good evidence of any adverse effects of 18 months of simvastatin treatment on lens opacity formation, using a variety of validated techniques to assess cataract development. Routine clinic follow up of visual symptoms and admission to hospital for ophthalmic procedures over 5 years of treatment was also reassuring, with no excess adverse outcomes observed with simvastatin.

One-year evaluation of excimer laser photorefractive keratectomy for myopia and myopic astigmatism. Melbourne Excimer Laser Group.

OBJECTIVE: To evaluate prospectively the efficacy and safety of excimer laser photorefractive keratectomy in the treatment of myopia and myopic astigmatism. METHODS: Up to 15 diopters (D) of myopia with or without astigmatism of less than 6 D was treated with an excimer laser (VISX Twenty/Twenty). One hundred fifty procedures have been followed up for more than 12 months. RESULTS: Postoperative refractions were generally stable after 3 months without significant early overcorrection. Of those eyes treated with spherical equivalents of 5 D or less, 96% were within 1 D of the targeted refraction after photorefractive keratectomy and 88% had uncorrected visual acuities of 20/40 or better. At 12 months, 77% of all 150 eyes treated achieved an uncorrected visual acuity of 20/40 or better and 81% were within 1 D of the intended correction. Nine eyes (6%) lost 2 or more lines of best corrected visual acuity and 14 (9%) gained 2 or more lines. Adverse reactions were reported in 12 patients (8%) during the postoperative period. CONCLUSIONS: Photorefractive keratectomy is capable of correcting low and moderate myopic errors with a relatively high degree of accuracy and safety. The predictability and stability of the postoperative refraction during the first 12 months seem to be good.

Necrotising anterior scleritis after pterygium surgery.

Necrotising anterior scleritis is a rare sequela of ocular surgery. Typically an intense scleral inflammation develops at or adjacent to the site of the previous surgery. Necrosis supervenes and may then progress circumferentially to involve much of the anterior sclera. Surgically induced necrotising scleritis (SINS) has been previously described after cataract extraction, trabeculectomy, retinal detachment and strabismus surgery. We report three cases of SINS following pterygium excision. In each case the disease was prolonged, progressive and required protracted immunosuppressive therapy.

Sterile ocular inflammatory reactions to monofilament suture material.

OBJECTIVE: To report six cases of sterile inflammatory reactions to fine monofilament suture materials, which is exceedingly rare in ophthalmology. METHODS: We report six patients (four underwent penetrating keratoplasty and two underwent cataract surgery) with unusually severe local inflammatory reactions to suture material. RESULTS: Patients developed multiple focal inflammatory infiltrates and corneal oedema related to 10/0 monofilament nylon sutures. Four patients had evidence of either atopy or raised serum IgE and one had an autoimmune disorder (systemic lupus erythematosis). Onset was four to 11 days in five cases and six weeks in one. Allograft reaction occurred in two of the four corneal grafts, and three grafts failed. One of the cataract patients developed significant against-the-rule astigmatism. Microbial cultures of corneal scrapings, donor corneal rims, and suture material were generally negative. Polymorphonuclear leucocytes were noted on Gram stain in four cases, and cytology of corneal scrapings demonstrated eosinophils in one case. CONCLUSIONS: Sterile inflammatory reactions to monofilament suture material are an uncommon complication of ocular surgery which may lead to corneal graft failure, and which is more common in atopic individuals. Systemic steroid therapy may be required.

Scedosporium prolificans sclerokeratitis.

BACKGROUND: The fungus Scedosporium prolificans was first described as a human pathogen in 1984, and has been associated with metastatic endophthalmitis and one previously reported case of sclerokeratitis. METHODS: We report a case of S. prolificans sclerokeratitis in the setting of late scleral necrosis complicating pterygium surgery with adjunctive beta-irradiation. RESULTS: A poor clinical response to topical natamycin and amphotericin B, and systemic itraconazole and ketoconazole was encountered. Enucleation was required, with subsequent microbiological cure. Pathological correlation is described. CONCLUSIONS: S. prolificans infections often respond poorly to medical therapy. Early surgical intervention is indicated in culture-proven scleritis due to Scedosporium prolificans.