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Biomedical subjects

Y K Au

Publications and source records attributed to Y K Au.

At least 19 recordsLinked to original sources
PubMed2001

A young male patient with persistent fever due to tuberculous peritonitis.

Tuberculous peritonitis is an uncommon disease in Hong Kong. We report a case of tuberculous peritonitis in a young male. The patient presented with persistent fever and intermittent cough for 1 month, but had no gastrointestinal symptoms. It was only through detection of slight abdominal ascites that subsequent abdominal paracentesis and laparoscopic biopsy confirmed the diagnosis. Appropriate antituberculous treatment was prescribed. Progress was complicated by persistent fever and liver function derangement, successfully managed by careful titration of antituberculous medications.

Adult↗
PubMed2000

Changes of cytochemical markers in the conjunctival and corneal epithelium after corneal debridement.

1. The aim of this study was to determine the epithelial changes of the conjunctiva and cornea up to 7 days after corneal debridement and the changes highlighted included (1) proliferation, (2) production of growth factor, (3) changes in calcium binding protein marker, (4) production of cytokine, and (5) maturity of the regeneration corneal epithelium. 2. The cytochemical changes of the corneal and conjunctival epithelia of rabbit were analyzed up to 7 days after debridement. 3. An increase in proliferating cell nuclear antigen (PCNA) was observed in the limbal epithelia 12 hr after lesion and reached a peak by 48 hr. 4. Some proliferating limbal cells also contained epidermal growth factor (EGF) beginning 24 hr after injury. The early limbal cell proliferation and the EGF production and their persistence until 7 days after lesion were likely involved with the process of regeneration. 5. Other positive markers appeared after lesion included tumor necrosis factor (TNFalpha) and calcium binding proteins S100A and S100B, which appeared mainly within the first 48 hr after lesion and then started to decline. The short appearance and the relatively small quantity of TNFalpha indicated that this cytokine was probably not very important in the repair process and its appearance might be related to the injury induced. The presence of S100A and S100B could be associated with both cell death after injury and the proliferation of new epithelium. 6. The cornea epithelium was still immature 7 days after lesion in that it still contained cytokeratin. 7. In conclusion, the critical hours of peak conjunctival and corneal changes after corneal debridement were in the first 2 days.

Animals↗
PubMed1997

Spontaneous corneal rupture in Noonan syndrome. A case report.

PURPOSE/METHODS: A variety of ocular and periocular manifestations have been described in Noonan syndrome. Collagen abnormalities have been described; however, to our knowledge spontaneous corneal rupture has not been reported. A forty-three-year-old female who presented with spontaneous corneal rupture was later diagnosed as having Noonan syndrome. RESULTS/CONCLUSIONS: Collagen abnormalities have been described with Noonan syndrome and this is likely the cause of corneal rupture in this patient.

Adult↗
PubMed1996

Increasing OR efficiency with a specialty services manual.

The successful operation of a modern ophthalmology OR is dependent on a knowledgeable, well-educated nursing staff. To improve communication and teamwork between ophthalmology surgeons and nursing staff members at the Louisiana State University Medical Center University Hospital, Shreveport, we developed an OR manual. We reduced our level of frustration by producing a manual that facilitates the day-to-day operation of the surgical services department. The manual provides consistent information for our ophthalmic surgical procedures; functions as a reference source; and promotes an efficient, productive OR. Although we designed this manual for the ophthalmology surgical service at our medical center, its structure can be applied to other surgical specialties.

Efficiency, Organizational↗
PubMed1996

Epikeratophakia to correct traumatic aphakia after penetrating keratoplasty.

A 19-year-old man with keratoconus sustained ocular trauma and became aphakic in his operated left eye 2 months after penetrating keratoplasty. Original corneal wound repair was performed without intraocular lens implantation. Attempts to correct his aphakia with a contact lens failed when the patient became intolerant to its use. As an alternative, the patient had elective epikeratophakia. A standard 8.5 mm lenticule was placed over existing corneal graft. This operation resulted in +12.25 diopters of correction and a best corrected visual acuity of 20/25 at 30 months postoperatively. There was no sign of abnormalities at the host cornea or the transplanted lenticule. This case indicates that epikeratophakia may be successfully performed over existing corneal grafts.

Adult↗
PubMed1996

Removal of a corneal foreign body through a lamellar corneal pocket.

A piece of glass was found in the posterior central cornea of a 43-year-old victim of a motor vehicle accident. The original entry of the foreign body had healed and epithelialized. This foreign body was removed through a peripheral corneal incision and corneal stromal pocket extended to the glass particle. This technique avoids creation of a corneal incision near the optical axis and prevents unwanted distortion of the corneal topography. The authors report this case to emphasize the importance of preserving corneal topography in corneal surgery.

Accidents, Traffic↗
PubMed1993

Radial keratotomy in an elderly patient.

A 74-year-old male complained of poor vision and diplopia as a result of cataract extraction and intraocular lens implantation. On refraction, we found -6.25 diopters (D) of myopia in his right eye. The patient, dissatisfied with wearing contact lenses and spectacles to correct vision, opted to have refractive corneal surgery. We performed a four-incision radial keratotomy with a 4 mm clear zone. This resulted in a 3.75 D (-2.5 D residual myopia) reduction in myopia at two months of follow-up. Our results indicate that radial keratotomy may be useful for correcting unacceptable myopia in older patients.

Aged↗
PubMed1993

Coagulase-negative staphylococci in conjunctivitis and blepharitis.

Coagulase-negative staphylococcus (C-NS) are regarded as normal flora of the lids and conjunctiva. The ability of these organisms to cause conjunctivitis and blepharitis can be overlooked or disregarded. To elucidate the role of individual C-NS species in these eye diseases we compared Staphylococcus sp. isolated from the conjunctiva and lids of 50 healthy volunteers with 248 strains of Staphylococcus isolated from patients with staphylococcal conjunctivitis or blepharitis. S. epidermidis was the most frequent species isolated from the conjunctiva and lids of both groups. S. aureus was isolated only from infected patients. No individual C-NS species was found to be significantly associated with eye disease, but the colony count of C-NS after isolation was a useful indicator of conjunctivitis and blepharitis. The ability of Staphylococcus to ferment mannitol or mannose was associated with isolates only from infected patients.

Blepharitis↗
PubMed1993

Lateral tarsorrhaphy and disposable soft contact lenses in aniridia patients after penetrating keratoplasty.

We report our experience with two patients with familial aniridia who underwent combined cataract extraction and penetrating keratoplasty. Persistent epithelial defects developed in all four eyes within 4 months. Combined lateral tarsorrhaphy and application of disposable soft contact lenses restored the integrity of the corneal epithelium, and 21 months after surgery, the grafts were clear and avascular.

Adult↗
PubMed1992

Bipolar cautery and internal thermal sclerostomy in a rabbit model.

Internal thermal sclerostomy (ITS) was performed unilaterally in 35 adult New Zealand rabbits using a pinpoint bipolar cautery probe and radio-frequency power supply, with the nonoperated eyes serving as controls. Standard trabeculectomy using a limbal-based flap was also performed on 10 additional rabbits, and served as a second bench mark for comparison with the ITS technique. Intraocular pressure (IOP) was measured in all eyes preoperatively and on postoperative days 2, 4, 6, and 8. A significant (P = .005) difference between the reduction in IOP in the ITS eyes and in the control eyes was found up to postoperative day 8; on that day the reduction in IOP was 5.2 mm Hg. IOP in the eyes undergoing standard trabeculectomy was significantly (P = .05) reduced up to postoperative day 2, and gradually decreased, to 2.5 mm Hg, on postoperative day 8. The greatest reduction in IOP (2.9 mm Hg) for these eyes also occurred on postoperative day 2. Complications of ITS included iris burn (23%), peripheral corneal edema (17%), and iritis (9%). No ruptured blebs, flat anterior chambers, hyphemas, or lens damage occurred. The potential advantages of the ITS procedure using the bipolar cautery probe include a decreased risk of cataract formation because of the curved probe design. The procedure is also technically simple to perform and requires only inexpensive and readily-available equipment.

Animals↗
PubMed1991

Peripartum haemoperitoneum.

We report the case of a young pregnant woman who presented with abdominal discomfort and giddiness. After an induced labour, the patient collapsed. Mid-line laparotomy revealed a ruptured and bleeding secondary deposit in the liver. A tumour of the sigmoid colon was also found.

Adult↗
PubMed1991

Goldmann tonometry and fluorescein solution: a way to avoid contact lens staining.

Topical instillation of fluorescein during standard Goldmann tonometry may cause subsequent contact lens staining. We evaluated a method of Goldmann tonometry that uses only a small amount of fluorescein. In this experimental technique, the fluorescein is applied only to the tip of the applanation cone with fluorescein-coated tissue paper. Thirty patients had their intraocular pressures (IOPs) determined by this method. The IOP measurements were then repeated on the same eyes after instillation of fluorescein directly onto their eyes. In addition, 20 soft contact lens wearers had their IOPs determined by the experimental method, with contact lenses fitted immediately after the measurements. There was no statistically significant difference between the IOPs measured by the standard technique and by the experimental method. In addition, no fluorescein staining was detected in the 20 soft contact lenses examined. Our results suggest that the proposed method is accurate and useful in determining IOP prior to soft contact lens fitting.

Contact Lenses, Hydrophilic↗
PubMed1990

A comparison of the wound integrity produced by various suture patterns in penetrating keratoplasty: a cadaver eye model.

We tested the watertightness of wound closure in penetrating keratoplasty as a function of suture pattern by performing a 7.5-mm penetrating keratoplasty on 12 human cadaver eyes using a variety of suture patterns. We then tested wound integrity by hydrostatically raising the intraocular pressure. In this cadaver eye model, we demonstrated that running sutures produced better wound closure than interrupted sutures using the same number of bites. A 16-bite running or a combined running-interrupted pattern produced more than ample watertightness in penetrating keratoplasty wound closure.

Cadaver↗
PubMed1990

Suture patterns and corneal graft rotation in the cadaver eye.

Torque and antitorque running sutures as described by Eisner are commonly used in penetrating keratoplasty. We tested the rotational effect of three different 16-bite running suture patterns on eight cadaver eyes, with the following results: (1) the torque pattern rotates the corneal graft counterclockwise by 0.7 +/- 0.1 mm at the wound or 11 degrees; (2) the antitorque pattern rotates the corneal graft clockwise by 0.7 +/- 0.1 mm at the wound or 11 degrees; (3) an intermediate "no torque" pattern, the bites of which form an isosceles triangle, produces no rotational effect. We recommend the use of a "no torque" pattern to minimize corneal graft rotation.

Cadaver↗
PubMed1990

Astigmatism and tissue-shape disparity in penetrating keratoplasty.

Tissue-shape disparity between the donor and recipient cornea is a major cause of astigmatism following penetrating keratoplasty. We studied the topographic effects of recipient or donor tissue deficiency (oval donor button or recipient hole) in a penetrating keratoplasty rabbit model. The results demonstrated that a crescent-shape block resection of 0.5 mm x 6.0 mm during penetrating keratoplasty induces 4 to 7 diopters of corneal astigmatism, with the steeper meridian along the axis of tissue deficiency. Corneal topography and vector analysis of astigmatism showed steepening along the axis of tissue deficiency and flattening 90 degrees away.

Animals↗
PubMed1989

A partial-thickness epithelial defect increases the adherence of Pseudomonas aeruginosa to the cornea.

Some patients with infectious keratitis have no clinically demonstrable corneal abrasion predisposing them to infection. Subtle, undetectable corneal injuries may facilitate bacterial adherence to the cornea, eventually leading to keratitis. To study this concept, we have developed a rabbit model in which a partial-thickness corneal epithelial defect was induced by filter paper impression on the cornea that removed one to two layers of corneal epithelium. Following this injury, the corneas were incubated with Pseudomonas aeruginosa, washed, and the number of bacteria adhering to the injured corneas as well as to control corneas was quantitated. Corneas treated with filter paper, either ex vivo or in vivo, allowed 20 times more bacteria to adhere than did the untreated control corneas (P less than 0.01). This superficial epithelial defect increased Pseudomonas adherence to the cornea for up to 72 hr after injury. When corneal injury was extended to the stroma, the adherence of Pseudomonas was further augmented as compared to adherence to the superficially injured cornea. Thus, we conclude that a clinically subtle, partial-thickness corneal epithelial injury can markedly facilitate the adherence of Pseudomonas aeruginosa, which may be an important predisposing factor for infectious keratitis.

Animals↗