Biomedical subjects

Gerard L Sutton

Publications and source records attributed to Gerard L Sutton.

8 recordsLinked to original sources

PubMed2005

Laser in situ keratomileusis for refractive error after cataract surgery.

PURPOSE: To evaluate the safety and efficacy of laser in situ keratomileusis (LASIK) to correct refractive error following cataract surgery. SETTING: The Eye Institute, Sydney, Australia. METHODS: This retrospective study reviewed 23 eyes (19 patients; 10 female, 9 male) treated with LASIK for refractive error following cataract surgery. The Summit Apex Plus and Ladarvision excimer laser and the SKBM microkeratome were used. The mean age was 63.5 years (range 50 to 88 years). The mean length of follow-up was 8.4 months (range 1 to 12 months) and mean interval between cataract surgery and LASIK was 12 months (range 2.5 to 46 months). RESULTS: The mean preoperative spherical equivalent refraction (SEQ) for myopic eyes was -3.08 +/- 0.84 diopters (D) (range -4.75 to -2.00 D) and for hyperopic eyes was +1.82 +/- 1.03 D (range +0.75 to +3.00 D). The mean improvement following LASIK surgery was greater for myopic than hyperopic eyes (myopic, 2.54 +/- 1.03 D versus hyperopic, 1.73 +/- 0.62 D; P=.033). The percentage of patients within +/-0.5 D of intended refraction post-LASIK surgery was 83.3% for myopic eyes and 90.9% for hyperopic eyes and all eyes were within +/-1.0 D of intended (P<.001). The percentage of eyes with uncorrected visual acuity of 20/40 or better in the myopic group improved from none preoperatively to 91.7% postoperatively (P<.001) and in the hyperopic group improved from 27.3% preoperatively to 90.9% postoperatively (P=.008). No eyes lost 2 or more lines of best corrected visual acuity. CONCLUSION: Laser in situ keratomileusis appears to be effective in correcting refractive error following cataract surgery. Longer-term studies are required to determine refractive stability.

Aged↗

PubMed2005

Six-year review of Acanthamoeba keratitis in New South Wales, Australia: 1997-2002.

AIM: To assess the incidence and risk factors for Acanthamoeba keratitis (AK), the diagnostic interval, and the efficacy and outcome of current treatment among the population of New South Wales, Australia. METHODS: A retrospective review was carried out of all cases of AK treated at the Sydney Eye Hospital between January 1997 and December 2002. RESULTS: Twenty patients were identified with a mean follow up of 24.8 +/- 21.5 months. Acanthamoeba keratitis constitutes 4.7% of severe infective keratitis treated at Sydney Eye Hospital. The mean interval from first presentation to diagnosis was 26.6 +/- 35.1 days overall; 17.2 +/- 33.1 days for those presenting directly to our unit (69% being diagnosed within 72 h of presentation), and 44.1 +/- 34.0 days for those first presenting elsewhere. Of those with a diagnostic delay >1 month, 57% had been mistakenly diagnosed with Herpes simplex keratitis. Sixteen (80%) wore contact lenses, and eight (40%) had additional risk factors including poor lens hygiene. Complications occurred in 16 (80%), with seven (35%) requiring surgical intervention. Visual acuity improved in 18 (90%), worsened in two patients (10%), and 75% achieved 6/12 or better at last follow up. CONCLUSIONS: Acanthamoeba keratitis is a rare infection, and contact lens wear remains the commonest association, with poor hygiene constituting significant additional risk. The visual outcome has improved with the availability of effective amoebicidal agents, but patients with a diagnostic delay and non-contact lens wearers are at increased risk of recurrent disease. A high index of clinical suspicion remains the most effective strategy in implementing early treatment, and enabling a favourable outcome.

Acanthamoeba Keratitis↗

PubMed2003

AlphaCor cases: comparative outcomes.

PURPOSE: To describe clinical outcomes after a novel type of corneal surgery, implantation of an artificial cornea, AlphaCor , and to evaluate outcomes in comparison with alternative keratoprostheses and high-risk grafts. METHODS: Case reports and data from a noncontrolled clinical trial and a literature review. RESULTS: The probability of AlphaCor retention to 1 year is 80%. Postoperative best corrected visual acuity ranges from Perception Light to 20/30. The most significant complications are stromal melts and optic depositions, for both of which the main risk factors have been identified. Complications can be managed without loss of the eye. CONCLUSION: Results from the clinical trial period have helped to determine the indications and risk factors for AlphaCor surgery and to refine surgical techniques. Continued monitoring of outcomes as the series increases will allow a more accurate determination of comparative outcomes. The series provides preliminary evidence that AlphaCor may have a lower incidence of complications than traditional keratoprostheses and may prove to be preferable to a donor graft in high-risk cases.

Aged↗

PubMed2002

Laser in situ keratomileusis for residual myopia after photorefractive keratectomy.

PURPOSE: To evaluate the efficacy and safety of laser in situ keratomileusis (LASIK) for myopic regression and undercorrection after photorefractive keratectomy (PRK). SETTING: The Eye Institute, Sydney, Australia. METHODS: Fifty eyes of 32 patients were treated by LASIK for residual myopia following primary PRK. The mean spherical equivalent refraction (SEQ) was -2.92 diopters (D) +/- 1.57 (SD) (range -0.75 to -7.88 D). The mean refractive cylinder was 0.96 +/- 0.74 D (range 0 to 3.50 D). For analysis, the eyes were divided into 2 groups: those with 0 or low corneal haze (Group 1) and those with severe corneal haze (Group 2). In Group 1, the SEQ was -1.99 +/- 0.79 D (range -0.75 to -3.75 D) and in Group 2, -3.77 +/- 1.62 D (range -0.75 to -7.90 D). The procedure was performed using the Chiron Automated Corneal Shaper and the Summit Apex Plus laser. The mean interval between PRK and LASIK was 25 months (range 9 to 59 months). The following parameters were studied before and after LASIK retreatment: SEQ, mean refractive cylinder, uncorrected visual acuity (UCVA), and best corrected visual acuity (BCVA). Complications after LASIK retreatment were evaluated. RESULTS: Six months after LASIK, the mean SEQ in all eyes was -0.65 +/- 0.86 D (range +1.50 to -3.35 D); 70.0% of eyes were within +/-1.00 D of emmetropia and the UCVA was 6/12 or better in 72.5%. The mean SEQ in Group 1 was -0.22 +/- 0.55 D (range -0.88 to -1.50 D) and in Group 2, -0.97+/- 0.92 D (range 0.12 to -3.25 D); the UCVA was 6/12 or better in 94.0% of eyes in Group 1 and in 56.0% in Group 2. No statistically significant between-group difference was found in lines of Snellen acuity lost or gained at 6 months. No eye lost more than 1 line of BCVA. CONCLUSIONS: Laser in situ keratomileusis appears to be a safe, effective, and predictable procedure for treating eyes with 0 or low haze with residual myopia after PRK. It is less predictable in eyes with severe haze.

Adult↗

PubMed2002

Outcomes of implantation of an artificial cornea, AlphaCor: effects of prior ocular herpes simplex infection.

PURPOSE: To review outcomes of AlphaCor artificial cornea implantation in patients with and without a history of ocular herpes simplex virus (HSV) and to determine whether herpetic eye disease is an indication for AlphaCor surgery. METHODS: Outcomes of the initial 40 implantations were reviewed and stratified by the presence of a history of ocular disease caused by HSV. Outcomes measures (complications, visual acuity gained) were compared. RESULTS: Eight of the 40 AlphaCor implantations (20%) were in patients with a history of ocular HSV. Six of these eight patients (75%) developed melt-related complications after AlphaCor insertion. Half of the affected patients required removal of the AlphaCor and replacement with a donor corneal graft to restore ocular integrity. In comparison, only six of the 32 (18.8%) patients without HSV developed a melt after AlphaCor insertion. Patients with HSV with devices in situ exhibited a mean loss of 0.3 line of best-corrected visual acuity compared with the preoperative visual acuity, whereas patients without HSV exhibited a mean gain of 1.4 lines of best-corrected visual acuity. CONCLUSIONS: The extensive lamellar corneal surgery involved in AlphaCor implantation may precipitate reactivation of latent HSV such that reactivation and resultant inflammation reduce device biointegration and facilitate melting of corneal stromal tissue anterior to the device. Although there may be some benefit from systemic antiviral medication, the current series is not large enough to demonstrate such a benefit, and melting can occur despite medication. The statistically significant difference in outcomes between recipients of AlphaCor with and without HSV is evidence that a history of HSV should be an exclusion factor for AlphaCor surgery.

Artificial Organs↗

PubMed2002

The effect of laser-assisted in situ keratomileusis on retinal nerve fiber layer measurements obtained with scanning laser polarimetry.

PURPOSE: Scanning laser polarimetry provides indirect measurements of retinal nerve fiber layer thickness by measuring the retardation of polarized laser light as it passes through the retinal nerve fiber layer. Laser-assisted in situ keratomileusis is a refractive technique by which corneal stromal photoablation is achieved by the structural and refractive changes induced by the excimer laser. Both techniques are becoming widely performed and there is some evidence that scanning laser polarimetry measurements are significantly changed after laser-assisted in situ keratomileusis. The authors performed a larger study to determine whether laser-assisted in situ keratomileusis induces predictable and consistent alterations in the measurement of retinal nerve fiber layer thickness. METHODS: Retinal nerve fiber layer thickness measurements using scanning laser polarimetry were performed 1 week before and 1 week after laser-assisted in situ keratomileusis in 30 consecutive eyes (16 patients) undergoing the procedure at The Eye Institute. RESULTS: Mean +/- SD preoperative spherical equivalent refraction was -4.66 +/- 2.40 D, mean ablation depth was 73.0 +/- 36.23 microm, and mean patient age was 40.6 +/- 8.7 years. Six of 12 retinal nerve fiber layer thickness measurements showed significant change (P < 0.05) after laser-assisted in situ keratomileusis. There was no correlation with corneal ablation depth (P > 0.05) for all parameters. CONCLUSION: Laser-assisted in situ keratomileusis significantly affects retinal nerve fiber layer thickness measurements obtained by scanning laser polarimetry. Sequential images should be interpreted with caution and new postoperative baseline images should be obtained.

Adult↗

PubMedDate not supplied

Laser in situ keratomileusis with Alcon CustomCornea.

PURPOSE: To report the 3-month results of our first cases of laser in situ keratomileusis (LASIK) with Alcon's CustomCornea. METHODS: Wavefront analysis was performed using the LADARWave aberrometer and ablation was performed with the LADARVision4000 system. Thirty-one eyes of 17 patients were analyzed prospectively, at 1 and 3 months after CustomCornea surgery. Psychophysical tests were performed, including high and low contrast acuity, and contrast sensitivity under scotopic and photopic conditions. In addition, psychometric testing was performed using a subjective vision questionnaire. RESULTS: Mean spherical equivalent refraction improved from a baseline -3.05 +/- 1.92 D to +0.02 +/- 0.28 D at 3 months (28 eyes). At 3 months, 46.4% (13 eyes) had uncorrected visual acuity of 20/16, 92.7% (26 eyes) had 20/20, and 100% (28 eyes) had 20/25 uncorrected visual acuity. Three months after CustomCornea surgery, there was a statistically significant improvement in contrast sensitivity under both scotopic and photopic conditions, and a statistically significant increase in third and fourth order aberrations. There was a statistically significant improvement in visual quality as measured by the subjective vision index, increasing from a preoperative mean 66.62 to 87.63 at 3 months after surgery. CONCLUSIONS: CustomCornea was an improvement over conventional LASIK as measured by most psychophysical and psychometric parameters. The relationship between higher order aberrations and other psychophysical and psychometric measurements needs more analysis.

Adult↗

PubMedDate not supplied

Development of a questionnaire to assess subjective vision score in myopes seeking refractive surgery.

PURPOSE: To assess vision in patients with myopia and myopic astigmatism before and after refractive surgery. METHODS: A prospective controlled study of visual quality amongst myopes and astigmatic myopes. Focus groups, ophthalmic surgeons, and questionnaire experts devised a Subjective Vision Questionnaire (SVQ), modified after a pilot trial. Participants were administered the SVQ before clinical evaluation. Items answered by over 95%, with factor loadings > 0.55 were included. Test-retest reliability was assessed by repeat testing. Factor analysis identified groups of questions measuring particular dimensions of data. RESULTS: Sixty-seven items were answered by 128 patients and reduced to 24 items in a final questionnaire. Factor analysis identified six types of questions within the questionnaire, the most important of which was related to driving. CONCLUSION: The simplicity, low cost, and psychometric properties of the Subjective Vision Questionnaire support its use clinically and in research.

Adult↗