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Biomedical subjects

D S Lam

Publications and source records attributed to D S Lam.

At least 145 records · Page 8Linked to original sources
PubMed1998

An uncommon malignant neoplasm of the caruncle: report of a case of undifferentiated carcinoma.

The caruncle is an uncommon site for the occurrence of neoplasm despite its diverse histological composition of conjunctival, lacrimal, and skin tissues. The following case report describes a 66-year-old man who suffered from a primary undifferentiated carcinoma of the left caruncle. He remained well with no evidence of recurrence 24 months after a complete surgical excision. To our knowledge, this could represent the first case of undifferentiated carcinoma of the caruncle to be reported in the English literature. Early detection and complete excision for this type of lesion could lead to a satisfactory clinical outcome.

Aged↗
PubMed1998

Autogenous palmaris longus tendon as frontalis suspension material for ptosis correction in children.

PURPOSE: To determine the safety and efficacy of autogenous palmaris longus tendon as a sling material in frontalis suspension surgery for ptosis correction in children. METHODS: In a prospective study, the authors evaluated 15 frontalis sling suspension surgeries using palmaris longus tendon in 14 consecutive children with congenital ptosis. The method of harvesting the palmaris longus tendon is described in detail. RESULTS: The mean age of the patients was 4.7 years (range, 2 to 7 years). At a mean follow-up of 30 months (range, 20 to 40 months), all ptotic eyelids were successfully corrected with good final lid position. No recurrence of ptosis was encountered. In one eye, knot slippage of the sling was related to upper eyelid trauma, which was readily repaired. Otherwise, no exposure keratitis, wound infection, eyelid contour abnormality, or ptosis overcorrection occurred. There were no complications associated with the palmaris longus tendon donor site. CONCLUSION: Frontalis suspension with autogenous palmaris longus tendon appears to be an effective treatment for congenital ptosis with poor levator function in children. Its use as an alternative material to fascia lata for sling surgery in children can be considered.

Blepharoptosis↗
PubMed1998

An analysis of the incidence and risk factors of developing severe keratopathy in eyes after megavoltage external beam irradiation.

OBJECTIVE: To investigate the incidence and risk factors of developing severe keratopathy in eyes exposed to megavoltage external beam irradiation. DESIGN: Retrospective noncomparative case series. PARTICIPANTS: The authors evaluated 88 eyes of 88 consecutive patients who had received irradiation of an entire orbit during radiation therapy for nasopharyngeal carcinoma. Mean follow-up was 40 months (range, 24-106 months). INTERVENTION: Slit-lamp biomicroscopic findings of the cornea after irradiation were categorized into four grades in accordance with a standard protocol. Grade 3 or above changes were defined as severe radiation keratopathy. MAIN OUTCOME MEASURES: The incidence of severe radiation keratopathy was evaluated along with patient's age, radiation dose, lacrimal shielding, and tumor involvement of the trigeminal nerve. RESULTS: Severe radiation keratopathy developed in 32 patients. Mean latency was 15 months (range, 4-36 months). Its incidence increased from 0% after doses less than 59 Gy to 100% after doses greater than 70 Gy. Between 59 Gy and 69 Gy, the adverse factor was omission of lacrimal shield during radiation therapy (P < 0.01). CONCLUSION: Radiation dose to the cornea is the most important factor in determining the outcome of radiation keratopathy. When the threshold dose is reached, visual prognosis is grave despite protection of the lacrimal gland. Clinical trials on newer strategies to treat ocular surfaces exposed to heavy irradiation are necessary.

Adult↗
PubMed1998

Immediate argon laser peripheral iridoplasty as treatment for acute attack of primary angle-closure glaucoma: a preliminary study.

OBJECTIVE: This study aimed to examine the intraocular pressure (IOP)-lowering effects and safety of immediate argon laser peripheral iridoplasty (ALPI) as a first-line treatment for acute primary angle-closure glaucoma (PACG). DESIGN: A prospective cohort study. PARTICIPANTS: Ten consecutive patients with their first attack of PACG, with IOP of 40 mmHg or greater, were recruited into the study. INTERVENTION: On presentation, each patient received topical pilocarpine (4%) and timolol (0.5%) and immediate ALPI as primary treatment. The IOPs at 15, 30, and 60 minutes after ALPI were documented by applanation tonometry. When the corneal edema had settled, laser peripheral iridotomy was performed as a definitive treatment. MAIN OUTCOME MEASURES: The IOP, corneal edema, and complications from ALPI were measured. RESULTS: The mean IOP of this group of patients was reduced from 59.5+/-10.4 mmHg to 28.7+/-14.9 mmHg at 15 minutes, 21.7+/-13.1 mmHg at 30 minutes, and 16.0+/-9.4 mmHg at 60 minutes after ALPI. No complications from the laser procedure were encountered during the study period. In nine of the ten patients, the corneal edema cleared up 1 hour after ALPI. In the remaining patient, the cornea cleared up 2 hours after ALPI. CONCLUSION: From this preliminary study, immediate ALPI, without adjunctive systemic antiglaucoma treatment, appeared to be very effective in controlling the IOP and returning corneal clarity in acute PACG. Its safety also appeared reassuring and did not have the risks associated with conventional systemic therapies.

Acute Disease↗
PubMed1998

Intraoperative mitomycin C to prevent recurrence of pterygium after excision: a 30-month follow-up study.

OBJECTIVE: The purpose of the study was to examine the efficacy of intraoperative mitomycin C (MMC) in preventing recurrence of pterygium after excision and the postoperative complications encountered. DESIGN: The study design was a prospective, randomized, clinical trial. PARTICIPANTS: A total of 180 primary and recurrent pterygia were recruited for the study. They were randomized into five groups: A, control with no MMC; B, 0.02% MMC for 5 minutes; C, 0.04% MMC for 5 minutes; D, 0.02% MMC for 3 minutes; and E, 0.04% MMC for 3 minutes. INTERVENTION: All patients received pterygium excision with or without the above four modes of intraoperative MMC application. MAIN OUTCOME MEASURES: Recurrence of pterygium and postoperative complications such as superficial scleral melting were measured. RESULTS: At a mean follow-up of 30 (groups A-C) and 20 months (groups D and E), the respective recurrence rates in groups A through E were 75%, 8.3%, 8.6%, 42.9%, and 22.9%. There were two cases of postoperative superficial scleral melting in group C. Otherwise, no major postoperative complications were encountered. CONCLUSIONS: The midterm results of a single intraoperative application of MMC at the concentration of 0.02% for 5 minutes are encouraging. Its application as an adjunctive therapy for the surgical treatment of pterygium appeared to be safe and effective. However, because of the possibility of serious late complications, the authors suggest that this procedure be reserved for patients who have high probability of recurrence after excision of pterygium.

Adult↗
PubMed1998

Phacoemulsification, primary posterior capsulorhexis, and capsular intraocular lens implantation for uveitic cataract.

PURPOSE: To evaluate the safety and efficacy of phacoemulsification, primary posterior capsulorhexis (PCCC), and primary intraocular lens (IOL) implantation for uveitic cataracts. SETTING: Institutional practice. METHODS: Fifteen consecutive eyes of 13 patients with various causes of uveitis received anterior capsulorhexis, phacoemulsification, PCCC, and in-the-bag implantation of a heparin-surface-modified IOL for visually disabling cataract. The safety and efficacy of the combined operation were studied prospectively. RESULTS: At a mean follow-up of 16.9 months (range 8 to 30 months), all eyes had a clear central visual area. Fourteen of 15 eyes (93.3%) had good visual improvement after surgery. Eight eyes (53%) achieved a best corrected visual acuity (BCVA) of 20/30 or better and 6 (40%), 20/20 or better. Seventy-three percent of eyes attained a BCVA of 20/80 or better. The mean improvement in visual acuity was 5.2 Snellen lines (range 0 to 11 lines). No cases of uveitis flare-up or other major complications related to the cataract surgery occurred. CONCLUSIONS: The study's preliminary results are encouraging and indicate that phacoemulsification, PCCC, and IOL implantation can be considered in patients with visually disabling uveitic cataract.

Adolescent↗
PubMed1998

Short-term results of scleral intraocular lens fixation in children.

PURPOSE: To study the safety and efficacy of scleral intraocular lens (IOL) fixation in children. SETTING: A university practice. METHODS: This retrospective review evaluated the results and complications in 6 consecutive eyes of 3 children who had anterior vitrectomy, with or without lensectomy, and scleral IOL fixation to correct ectopia lentis or aphakia. RESULTS: At a mean follow-up of 17.3 months (range 13 to 21 months), all eyes had a stable and well-positioned posterior chamber IOL and good visual improvement. The only complication was asymptomatic pupillary capture of the IOL in 3 eyes. Reversal of the pupillary capture was achieved by pupil dilation with the patient in a supine position. CONCLUSIONS: The preliminary results of scleral IOL fixation in children are encouraging. The procedure's application in well-selected cases can be considered. However, its long-term safety and efficacy must be further assessed through studies with larger sample sizes and a longer follow-up.

Aphakia, Postcataract↗
PubMed1998

The use of combined intravenous pulse methylprednisolone and oral cyclosporin A in the treatment of corneal graft rejection: a preliminary study.

PURPOSE: Oral cyclosporin A used in addition to high-dose intravenous pulse methylprednisolone has been shown to have an adjunctive effect in reversing the rejection of liver and renal transplants. The aim of this prospective study was to evaluate the benefits and risks of this combined drug therapy in acute corneal graft rejection. METHODS: Eleven patients with acute corneal graft rejection received the combined regimen of a single pulse of intravenous methylprednisolone (500 mg) and a low dose of oral cyclosporin A (to maintain a trough blood level of 100-200 micrograms/l). RESULTS: At a mean follow-up of 16.5 months (range 8-22 months) from the presentation of the graft rejection, reversal of graft rejection was achieved in 10 of 11 cases (90.9%). No recurrence of graft rejection was encountered during the study period. One patient developed a duodenal ulcer, which healed after medical treatment. No other complications were encountered. CONCLUSIONS: The high efficacy and low risk of the combined regimen demonstrated in this preliminary study call for a larger-scale prospective double-masked study to confirm the value of this treatment protocol.

Acute Disease↗
PubMed1998

Post-keratoplasty endophthalmitis caused by Proteus mirabilis.

A diabetic patient who underwent a triple procedure (penetrating keratoplasty, cataract extraction and posterior chamber intraocular lens implantation), developed endophthalmitis caused by Proteus mirabilis. The source of infection was the infected donor cornea, which was imported from Sri Lanka. The organism was resistant to gentamicin, which was the only antibiotic present in the storage medium. On top of an aggressive antibiotic treatment regime (topical, systemic and intravitreal), exchange of the infected with a fresh corneal graft and pars plana vitrectomy were performed. The patient had a speedy recovery and the visual outcome was 20/40 two and a half years after the incident. To our knowledge, post-keratoplasty endophthalmitis caused by P. mirabilis has never been reported in the literature. We report herein such a case with good visual outcome. Newer storage medium, such as Optisol GS, might have a role in preventing keratoplasty-related infection.

Aged↗
PubMed1998

Benign fibrous histiocytoma of the choroid.

Benign fibrous histiocytoma (BFH) is a common soft tissue tumour. However, its occurrence in the orbit was not well recognised in the past. It is only in recent years that this condition has become more frequently diagnosed. Now, it is believed to be the commonest mesenchymal tumour of the orbit in adults. Its occurrence in the uveal tract is, however, exceedingly rare. Only one case of presumed fibrous histiocytoma of the choroid has been reported in the literature. We report herein a case of BFH of the choroid in the left eye of a Chinese woman. The patient presented with a huge but asymptomatic raised choroidal mass. Results of choroidal biopsy showed no sign of malignancy but definitive diagnosis could not be made. Enucleation was finally performed. The diagnosis was made on detailed evaluation of the results of the immunohistochemical staining and the ultrastructural findings. The patient remained well at the latest follow-up, which was 33 months after enucleation. Although BFH of the choroid is vary rare, its benign nature and the availability of choroidal biopsy for tissue diagnosis make it important to include this as one of the differential diagnoses for amelanotic choroidal mass.

Aged↗
PubMed1998

Combined phacoemulsification, pars plana vitrectomy, removal of intraocular foreign body (IOFB), and primary intraocular lens implantation for patients with IOFB and traumatic cataract.

PURPOSE AND METHODS: Small-incision cataract extraction by phacoemulsification through an anterior continuous circular capsulorhexis, pars plana vitrectomy, forceps removal of intraocular foreign body (IOFB) and primary intraocular lens implantation were performed in 4 eyes (4 patients) with IOFB and traumatic cataract, as an emergency combined procedure. RESULTS: At a mean follow-up of 12.3 months (range 7-19 months) the best corrected visual acuity of the 4 eyes ranged from 6/6 to 6/12. The only complication encountered in our series was an opacified posterior capsule that developed 10 months post-operatively in one case. This was easily dealt with by neodymium:YAG laser capsulotomy, with good final visual outcome. CONCLUSIONS: The results of combined one-stage instead of sequential surgeries, and phacoemulsification instead of lensectomy or extracapsular cataract extraction for patients with IOFB and cataract are encouraging. It could be a good option in selected cases. However, the safety and efficacy of this combined procedure need to be evaluated further by a larger-scale, longer follow-up study.

Adult↗
PubMed1998

Bilateral arteritic central retinal artery occlusion in a Chinese patient.

PURPOSE: To report the first case of bilateral central retinal artery occlusion caused by giant cell arteritis in a Chinese patient. METHODS: We studied a Chinese patient who had a history of weight loss, calf claudication and sequential right and left central retinal artery occlusion. RESULTS: The erythrocyte sedimentation rate was greater than 150 mm/h. Temporal artery biopsy confirmed the diagnosis of giant cell arteritis. Systemic steroid prevented further visual loss in the second eye. CONCLUSIONS: We believe that this is the first report in literature on the ophthalmological presentation of giant cell arteritis in a Chinese patient. Giant cell arteritis as a cause of central retinal artery occlusion should always be on the list of differential diagnosis, as early diagnosis and treatment may help to salvage the first eye and prevent blindness from developing in the second eye.

Aged↗