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Dive into the research topics where Joan S.K. Ng is active.

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Featured researches published by Joan S.K. Ng.


Ophthalmology | 1997

Ocular-hypertensive Response to Topical Steroids in Children

Alvin K H Kwok; Dennis S.C. Lam; Joan S.K. Ng; Sek-Jin Chew; Mark O M Tso

OBJECTIVE The purpose of the study is to investigate the rate and degree of ocular-hypertensive response to topical steroids in Chinese children. DESIGN The study design was an institutional, randomized, clinical trial. PARTICIPANTS A total of 19 consecutive patients were studied. INTERVENTION Topical steroids were administered to Chinese children younger than 10 years of age who underwent bilateral strabismus surgery. One eye was randomized to receive topical 0.1% dexamethasone (DMS), whereas the fellow eye received 0.1% fluorometholone (FML) six times per day for up to 4 weeks. Intraocular pressure (IOP) was measured on the day before operation and at postoperative days 1, 3, 6, 10, 13, and 27, then every 2 weeks thereafter until the IOP fell to preoperative levels. Topical steroids would be stopped if IOP was 30.00 mmHg or greater. MAIN OUTCOME MEASURES Peak IOP and maximal change of IOP from baseline were measured and categorized into low, intermediate, and high levels. Time to peak IOP also was studied. RESULTS A total of 16 patients were included. The peak IOP for DMS-treated eyes was 30.66 +/- 8.35 mmHg (range, 13.00-48.00 mmHg), whereas that in FML-treated eyes was significantly lower at 20.66 +/- 6.03 mmHg (range, 11.30-36.30 mmHg) (P = 0.001). The maximal change in IOP ranged from -2.60 to +31.00 mmHg in DMS-treated eyes (mean, 15.48 +/- 8.71 mmHg), almost double that of FML-treated eyes (range, +1.00 to +17.00 mmHg; mean, 5.83 +/- 4.96 mmHg) (P = 0.001). When the ocular-hypertensive responses of both DMS and FML groups were categorized into three levels of severity, significant differences were found between the two treatment groups (P = 0.001). In the DMS group, nine patients (56.25%) were high responders and six patients (37.5%) were intermediate responders. In the FML group, only one patient (6.25%) was a high responder. CONCLUSIONS The ocular-hypertensive response to topical DMS in children occurs more frequently, more severely, and more rapidly than that reported in adults. A total of 56% of the studied children, all younger than 10 years of age, were high responders to topical DMS. Of these, 89% attained their peak IOP within 8 days. Its use in children should best be avoided if possible. It would be desirable to monitor the IOP when it is being used. Conversely, FML produced a much less ocular-hypertensive effect and therefore poses an acceptable risk of clinically significant pressure elevation.


American Journal of Ophthalmology | 1998

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

Dennis S.C. Lam; Joan S.K. Ng; George P.M. Cheng; Randa T.H. Li

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.


Journal of Cataract and Refractive Surgery | 2000

Scleral fixation of a capsular tension ring for severe ectopia lentis

Dennis S.C. Lam; Alvin L. Young; Alfred T.S Leung; Srinivas K Rao; Joan S.K. Ng

A 4-year-old boy with bilateral idiopathic and progressive ectopia lentis had phacoaspiration of the lens and capsular tension ring (CTR) insertion in his left eye. Postoperatively, lens capsule centration remained poor. Single-point scleral fixation of the CTR was performed and centration of the lens capsule achieved. In-the-capsule intraocular lens (IOL) implantation was tried, but excessive IOL manipulation sliced open the capsule at the equator. Anterior vitrectomy and scleral IOL fixation were required. A similar approach was adopted in the right eye with meticulous attention given to gentle maneuvers. The operation was uneventful, with good IOL centration. Three and 11 months after surgery in the right and left eye, respectively, best corrected visual acuity was 20/50 in both eyes. Scleral fixation of the CTR, accompanied by gentle IOL manipulation, is an option to improve IOL centration in patients with severe zonular deficiency.


Journal of Cataract and Refractive Surgery | 1998

Short-term results of scleral intraocular lens fixation in children

Dennis S.C. Lam; Joan S.K. Ng; John K. H. Chua; Alfred T.S Leung; Clement C.Y. Tham

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.


Eye | 1997

Cystic schwannoma of the orbit

Dennis S.C. Lam; Joan S.K. Ng; Ka F. To; Victor Abdulah; Ct Liew; Mark O M Tso

Cystic schwannoma of the orbit is unreported in the world literature. A 54-year-old Caucasian man presented to our clinic with a 5 year history of progressive right-sided proptosis and diplopia. A large paramedian cystic mass displacing the right globe downwards and laterally was demonstrated. From the clinical and radiological features, the presumptive diagnosis of right frontal sinus mucocoele was made. However, the excisional biopsy of the lesion revealed the rare diagnosis of cystic schwannoma, arising from a branch of the first division of the trigeminal nerve. Post-operatively, the patient had a smooth recovery with visual acuity of 20/20 in each eye; full binocular single vision was also re-established. The differential diagnoses of cystic orbital mass, and the radiological and histological findings of the lesion, are described and discussed.


Cornea | 2002

Bilateral congenital corneal keloids and anterior segment mesenchymal dysgenesis in a case of Rubinstein-Taybi syndrome.

Srinivas K Rao; C P Pang; Winnie W. Y. Li; Joan S.K. Ng; William V. Good; Dennis S.C. Lam

Purpose. To report the unusual association of bilateral corneal keloids and anterior segment mesenchymal dysgenesis in a child with Rubinstein–Taybi syndrome. Methods. Case report of a 2-year-old boy. Results. Excision of the epicorneal mass in the right eye was followed by recurrence of the lesion. Multiple penetrating keratoplasties were unsuccessful in reconstructing the anterior segment because of recurrent corneal epithelial breakdown, suggesting limbal stem cell insufficiency. Histopathology and electron microscopy of the excised mass lesion showed features typical of a corneal keloid: thickened keratinized epithelium, absent Bowmans layer, and fibrovascular hyperplasia, with haphazard orientation of the collagen lamellae. Ultrasound biomicroscopy and intraoperative findings suggested a diagnosis of Peter anomaly, but genetic analysis did not show a PAX6 mutation. Conclusion. The findings in our patient add to the spectrum of ocular changes described in Rubinstein–Taybi syndrome and confirm earlier reports of poor ocular prognosis in corneal keloids and Rubinstein–Taybi syndrome.


Journal of Cataract and Refractive Surgery | 2001

Cystoid macular edema after pediatric intraocular lens implantation: fluorescein angioscopy results and literature review

Srinivas K Rao; Krishnamoorthy Ravishankar; G Sitalakshmi; Joan S.K. Ng; Christopher B O Yu; Dennis S.C. Lam

Purpose: To evaluate the occurrence of cystoid macular edema (CME) after lens extraction, anterior vitrectomy, and intraocular lens implantation (IOL) in children using angioscopy after administration of oral fluorescein. Setting: Centers in Tamil Nadu, India, and Hong Kong, China. Methods: This study comprised 18 children (28 eyes) who had cataract extraction, posterior capsulorhexis, anterior vitrectomy, and in‐the‐bag IOL implantation. The presence of CME was evaluated 1 week and 4 to 6 weeks after surgery using fluorescein angioscopy. Results: Anterior chamber fibrin occurred in 4 eyes (14.3%). Fluorescein angioscopy was performed 1 week after surgery in all eyes and after 1 month in 25 eyes (89.3%). No eye demonstrated the presence of CME on fluorescein angioscopy. Conclusions: Cystoid macular edema did not occur in the early period after pediatric cataract surgery using current surgical techniques. Longer follow‐up is required to ascertain the incidence of CME in the late postoperative period.


Eye | 1997

EARLY CORRECTION OF SEVERE UNILATERAL INFANT PTOSIS WITH THE MERSILENE MESH SLING

Dennis S.C. Lam; Sonal Gandhi; Joan S.K. Ng; Ivan Ngan Chen; Peter S.K Kwok; Guy H Chan

Ten consecutive cases of severe unilateral congenital ptosis were surgically corrected before 1 year of age (range 3-11 months) in an attempt to achieve early functional and cosmetic improvement. In all cases, a frontalis suspension using Mersilene mesh was performed. With a mean follow-up of 40.3 months (range 33-54 months), all patients achieved normal or near normal eyelid position and all had their chin-up head posture resolved. One patient developed a mild exposure keratitis that was treated successfully with topical antibiotics and lubricants. Our findings suggest that the Mersilene mesh sling has good potential for ptosis management in infants who are too young for fascial harvesting. However, a larger series with a longer follow-up period is required before the eventual safety and efficacy of the Mersilene mesh sling can be properly ascertained.


British Journal of Ophthalmology | 2003

Efficacy of lignocaine 2% gel in chalazion surgery

R T H Li; Jimmy S. M. Lai; Joan S.K. Ng; Ricky W.K. Law; E M C Lau; Dennis S.C. Lam

Background/aims: To determine whether topical 2% lignocaine (lidocaine) gel is an effective anaesthetic agent for chalazion surgery. Methods: In a randomised controlled clinical trial, 57 subjects aged 12 years or over requiring incision and curettage for chalazion were recruited over an 8 month period. Patients were randomised into two groups. One group received 1.5 ml of lignocaine 2% injection and the other 1.5 ml of lignocaine 2% gel topically. Standard incision and curettage was then performed. The primary outcome of interest was the total pain experienced during the entire procedure including anaesthetic administration as well as incision and curettage. The pain from the local anaesthetic administration and during incision and curettage was assessed independently using a visual analogue scale (0–100). The sum of these two scores would be the total pain score out of 200. “Fear of injection” score (0–100) was also assessed. Results: There was a statistically significant difference in the mean total pain scores between the injection and the gel groups (95.6 v 57.0) (p <0.001) (α = 0.05) (1 − β = 0.9394). There was a statistically significant difference in the mean scores on “pain of anaesthetic administration” (47.0 v 5.5) (p <0.000). There was no statistically significant differences in the mean scores on “fear of injection” (43.9 v 47.7) (p = 0.668) and “pain during incision and curettage” (48.28 v 51.4) (p=0.679). Conclusions: Lignocaine 2% gel is effective in chalazion surgery especially in lowering the pain caused by anaesthetic administration.


Eye | 1999

Primary orbital Ewing's sarcoma: Report of a case and review of the literature

Dennis S.C. Lam; Chi K. Li; Lulu L Cheng; Jennifer Gek Choo Teo; K. W. Chik; Wing Hong Kwan; Joan S.K. Ng; William W L Poon; Patrick Man Pan Yuen

Primary orbital Ewings sarcoma is a very rare condition. Since the first case was reported in 1950, only 7 other cases have been reported in the English literature. Herein we describe the ninth, the only bilateral and the youngest case of primary orbital Ewings sarcoma occurring in a 2-year-old boy, who presented to us with bilateral painless proptosis. Tissue biopsy of the tumour was obtained through the nasal sinus. Immunohistological studies of the biopsy tissue confirmed the diagnosis of Ewings sarcoma. No distant site of the tumour was found so this was considered a primary orbital tumour. Combined chemotherapy and radiotherapy without surgical resection achieved an encouraging result in that the patient has remained in remission for 30 months after completion of treatment. The successful use of combined chemotherapy and radiotherapy, without surgery, adds further support to evidence that surgical excision may be avoided in selected cases of primary orbital Ewings sarcoma.

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Dennis S.C. Lam

The Chinese University of Hong Kong

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Christopher B O Yu

The Chinese University of Hong Kong

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Alfred T.S Leung

The Chinese University of Hong Kong

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Alvin L. Young

The Chinese University of Hong Kong

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K. W. Chik

The Chinese University of Hong Kong

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Randa T.H. Li

The Chinese University of Hong Kong

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Ricky W.K. Law

The Chinese University of Hong Kong

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Chi Pui Pang

The Chinese University of Hong Kong

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Hunter K. L. Yuen

The Chinese University of Hong Kong

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