Post-capsulotomy dysphotopsia in monofocal versus multifocal lenses.

PURPOSE: To compare the photic symptoms experienced by patients with the monofocal SI30 intraocular lens (IOL) with the refractive multifocal SA40 Array IOL after capsulotomy. METHODS: In this prospective cohort study, 49 eyes of 49 patients (20 multifocal, 29 monofocal IOLs) were assessed following uncomplicated cataract extraction and Nd:YAG capsulotomy equal to the scotopic pupillary diameter. Subjects with post-operative refraction of +/-1.00 or more DS, +/-1.00 or more DC, concurrent ocular pathology, LogMAR acuity of worse than 0.3 for distance or 1.0 for near were excluded. Glare and halo were assessed objectively with computer-generated psychophysical tests (Glare and Halo) and subjective dysphotopic symptoms were evaluated with Tester, Javitt, Winther-Neilsen and Sedgewick questionnaires. RESULTS: No significant difference was found for mean halo size (square degrees) between monofocals (121.33) and multifocals (97.32, p = 0.207) or for mean glare (percentage contrast), monofocals (7.881) and multifocals (7.353, p = 0.812). No significant differences in the subjective appreciation of dysphotopsia were found: Tester (p = 0.358), Javitt (p = 0.29), Winther-Neilson (p = 0.54) and Sedgewick questionnaires (p = 0.134). CONCLUSION: The posterior capsule is an important optical medium, which has not been fully considered in other comparative studies and its complete removal eliminates any confounding contribution. The results suggest that after capsulotomy, there is no significant difference in objective or subjective photic phenomena between monofocal and multifocal silicone lenses. Dysphotopic symptoms in patients with refractive multifocal IOLs were comparable to monofocal IOL patients after capsulotomy.

The laparotomy incision: a technique to facilitate capsulorhexis in microincision cataract surgery.

Microincision cataract surgery is a new technique in the development of cataract surgery and is not without difficulties. Creation of the continuous curvilinear capsulorhexis as performed in conventional coaxial phacoemulsification surgery does not apply as readily. The authors describe a method for initiating the continuous curvilinear capsulorhexis (the laparotomy incision) using only an inexpensive 25-gauge bent needle cystototome. The technique involves a long linear incision in the anterior capsule down the belly of the lens as a means of initiating the capsulorhexis. Advantages of the technique include the creation of a large capsular flap, which allows easier completion of the continuous curvilinear capsulorhexis through a smaller range of movement, avoiding "oar locking" in the small incision and creation of striae in the cornea. It also allows better maintenance of anterior chamber depth, minimizing risk of radial tears.

Glare and halo with refractive correction.

BACKGROUND: The aim of this investigation was to compare glare and halo with various methods of refractive correction. METHODS: Ninety-eight eyes of healthy pre-presbyopes were analysed for the presence of glare and halo using computer-generated stimuli. Subjects were divided into three groups: emmetropes without correction, single vision plastic lens spectacle wearers (with clean and dirty lenses) or single-vision soft contact lens wearers. RESULTS: No significant difference in glare was found among groups. Significant differences were noted in halos between emmetropes and both contact lens (p<0.001) and uncleaned spectacle groups (p<0.05) but not with cleaned spectacles. The reduction in halo size after cleaning the lenses was significant (p<0.0187). CONCLUSIONS: Contact lens and unclean spectacle wearers both have significantly larger halos than emmetropes and those wearing cleaned spectacle lenses. Unclean spectacles may affect the accuracy of results in psychophysical and clinical testing.

Fourier analysis of induced irregular astigmatism. Photorefractive keratectomy versus laser in situ keratomileusis in a bilateral cohort of hyperopic patients.

PURPOSE: To analyze corneal topographic data by Fourier analysis to determine differences in irregular astigmatism following spherical hyperopic correction by photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK). SETTING: Department of Ophthalmology, St. Thomas' Hospital, London, United Kingdom. METHODS: Thirty-six eyes of 18 patients with moderate hyperopia had LASIK in 1 eye and PRK in the other eye. The flap was cut on a nasal hinge with a Moria LSK One microkeratome. The laser was a Summit SVS Apex Plus with an optical zone of 6.5 mm and a blending zone of 1.5 mm. Corneal topographic data were acquired with a TMS-1 topographer (Computed Anatomy Inc.) preoperatively and 1, 3, 6, and 12 months postoperatively. The ASCII files containing the dioptric power values were extracted and analyzed with custom-written software to extract the Fourier harmonics. RESULTS: The irregular astigmatism increased in both groups postoperatively, peaking at 3 months and then decreasing over the next 9 months. There was no statistically significant difference between the 2 groups at any time point (P<.05). The change in the topographically derived equivalent sphere showed undercorrection in both groups at all time points. Regular astigmatism showed a marginal statistically significant increase in the LASIK group at 12 months (P =.049). CONCLUSION: Irregular astigmatism, equivalent sphere, and regular astigmatism were not significantly different in the PRK and LASIK groups during the follow-up. Based on the corneal topography, the 2 procedures induced an equal amount of irregular astigmatism.

Periocular Mohs micrographic surgery: Results of a dual-site day-surgery service.

PURPOSE. To assess the feasibility of day-surgery Mohs Micrographic Surgery (MMS) at dual sites. METHODS. MMS now has an established position for the management of skin tumour removal. The literature reports excellent results in terms of tissue preservation, complete tumour excision and recurrence rate. MMS involves an initial stage undertaken by dermatologists. The subsequent reconstructive phase can be undertaken either by the dermatologist or by an oculoplastic surgeon in cases of extensive defects. In the latter cases, special expertise is needed in order to achieve satisfactory cosmetic results. Centres offering MMS are few and are usually located in tertiary referral hospitals. In a large city of 12 million inhabitants like London there is only one centre offering MMS on the National Health Scheme. We have set up a dual-site day-surgery service since 1997, whereby a Mohs trained dermatologist in the first unit undertakes the initial ablative stage. The patient is then transferred to the second location, which is approximately three miles away; a trained oculoplastic surgeon then undertakes the reconstruction the same day. Rarely, defects are deemed too large for reconstruction and the patient discharged on the same day; patients are then admitted as inpatients for reconstruction the following day with oculoplastic, plastic, craniofacial and facio-maxillary services at hand. RESULTS. To date we have operated on 59 patients for removal of basal cell carcinomas (BCC). All patients had a biopsy-proven diagnosis of BCC before being referred to the dermatologist. Following liaison with the Dermatology Unit, surgery was scheduled so that the reconstruction could be undertaken in the Oculoplastic Unit at the second hospital on the same day. All patients' defects were reconstructed successfully. With the longest follow-up being 39 months so far, tumour recurrence has been 0%. CONCLUSIONS. A dual-site day-surgery service seems to be a feasible option where a MMS dermatologist is not present onsite. The logistic problem can be easily overcome with a proper liaison between the departments. A dual-site day-surgery MMS service provides a superior service compared with the 2 mm tumour-free margin excision and delayed surgical repair following histological examination advocated by other authors where MMS is not available on site. It is only with MMS that one can ensure complete tumour excision. Day-surgery is the preferred choice, both for patients and for financial considerations. We would therefore support the establishment of dual-site day-surgery MMS services where the reconstruction is undertaken in hospitals located away from the MMS dermatology unit, provided close collaboration exists between the two units to ensure the smooth transfer of patients.

The transnasal advancement flap: A technique for medial canthal area defects.

AIM. To illustrate an alternative technique for reconstructing defects in the medial canthal area following tumour removal. MATERIALS AND METHODS. Eight consecutive patients who underwent Mohs(1) micrographic surgery for removal of a basal cell carcinoma in the medial canthal area were prospectively recruited. An experienced dermatologist trained in Mohs(1) micrographic surgery removed the tumour, and subsequently an oculoplastic surgeon reconstructed the defect. An incision is made from the superior end of the defect superomedially towards the midline of the dorsum of the nose following one of the natural lines of the skin (spec name). The incision runs in arcuate fashion just medial to the eyebrow and then reaches the dorsum of the nose and extends on the contralateral aspect of the nose towards the medial canthal area. The skin is then undermined to free up the newly formed flap. The flap is advanced towards the lesion and fixed intra-dermally with Vicryl Rapide(R) sutures to ensure anchoring into the concavity of the medial canthal region. The skin is then sutured with prolene sutures. RESULTS. The defects presented were oval or round in shape with diameters ranging from 0.5 to 2 cm. In all cases the transnasal flap covered the entire area and the defect was successfully reconstructed. Mean follow-up is 10.8 months (+/-4.5 SD) (range 4-17 months); all patients had an excellent cosmetic result and were subjectively satisfied. CONCLUSIONS. The transnasal advancement flap seems to have some advantages over the usual reconstruction techniques in use to repair medium defects in the medial canthal area. These are the avoidance of vertical scars in the glabellar area, eyebrow hair is not transposed into the medial canthal area, the skin match is excellent, both in colour and thickness, and surgical scars are hidden within the natural lines of the nasal bridge. We advocate the use of this technique for all minor to medium skin defects.