Search PubMed⌕ Search

Biomedical subjects

Seo-Wei Leo

Publications and source records attributed to Seo-Wei Leo.

5 recordsLinked to original sources

Loop myopexy for treatment of myopic strabismus fixus.

In myopic strabismus fixus, there is acquired esotropia and hypotropia associated with restricted elevation and abduction. One possible etiology is an enlarged globe herniating superotemporally through the muscle cone. High-resolution magnetic resonance imaging (MRI) has demonstrated the inferolateral displacement of the lateral rectus (LR) muscle in this restrictive motility disorder. Surgical treatment is difficult. We report two cases of myopic strabismus fixus that were treated with a loop myopexy of the LR and superior rectus (SR) muscles.

Adult↗

Visual experience during phacoemulsification under topical anaesthesia: a nationwide survey of Singapore ophthalmologists.

BACKGROUND: All patients undergoing phacoemulsification under topical anaesthesia experience a variety of visual sensations that may be frightening in a small proportion of patients. This study evaluates Singapore ophthalmologists' knowledge and practices regarding patients' visual experience during phacoemulsification under topical anaesthesia. METHODS: A nationwide survey of all ophthalmologists in Singapore who had performed at least one cataract surgery within the last year was carried out. Questions regarding patients' experience were asked. Surgeons were also asked about patients' fear during surgery, usefulness of preoperative counselling and feedback from patients postoperatively. RESULTS: Of 105 ophthalmologists 89 responded, of which 44 performed phacoemulsification under topical anaesthesia. The percentage of respondents who thought that the patients experienced the various visual sensations were: no light perception (4.6%), light perception (97.7%), one or more colours (95.5%), flashes of light (77.3%), movements (90.9%), instruments (61.4%), surgeon's hands/fingers (56.8%), surgeon (47.7%) and change in brightness of light (90.9%). Although 52.3% of surgeons believed that patients may be frightened by their visual experience and 50.0% felt that preoperative counselling would be useful in reducing such fear, only 11.4% routinely offered preoperative counselling and 18.2% counselled their patients occasionally. In total, 50.0% ophthalmologists had patients who reported to them that they could see during surgery, whereas 20.5% had been told by patients that they were frightened by the visual experience. CONCLUSION: Despite the awareness of patients' visual experience and the belief that preoperative counselling may be useful, most ophthalmologists do not counsel their patients preoperatively.

Anesthesia, Conduction↗

Modulation transfer functions in children: pupil size dependence and meridional anisotropy.

PURPOSE: This study quantified preschool children's optical quality in terms of their aberrations and modulation transfer function (MTF), and examined the dependence of MTF on pupil size and grating orientation. METHODS: Aberrometry was used to measure Zernike coefficients in 34 Chinese preschool children (18 males, 16 females; aged 4.95-6.89 years; mean, 5.91 +/- 0.56). For each subject, after mathematical correction for refractive error, these wavefront errors were used to calculate MTF (lambda = 550 nm) for pupil sizes from 1 to 5 mm and for gratings at orientations in 15 degrees intervals. RESULTS: Aberrations were correlated between right and left eyes, for wavefront RMS and some Zernike coefficients. Average aberrometry results showed that third-order terms predominated, in addition to some positive spherical aberration with an average higher order root mean square (RMS) of 0.20 micro m over a 5-mm pupil. Average MTFs were optimal for 3-mm pupil sizes at lower spatial frequencies (<69 cyc/deg) and slightly better than those found by similar techniques in young adults. Heights of MTFs were significantly related to higher order RMS (Spearman rho = -0.926). MTFs showed a small meridional anisotropy for 3-mm pupils, with average MTF for vertical gratings (horizontal modulation) being slightly, but significantly better than for horizontal gratings (vertical modulation). There was no evidence of an oblique effect in the optics of these children. CONCLUSIONS: In these children, ocular optical quality is pupil dependent, shows slight meridional anisotropy and is slightly better than that for young adults.

Anisotropy↗