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Biomedical subjects

O B Hadden

Publications and source records attributed to O B Hadden.

At least 19 recordsLinked to original sources
PubMed1999

Visual, refractive, and subjective outcomes after photorefractive keratectomy for myopia of 6 to 10 diopters using the Nidek laser.

PURPOSE: To analyze the results of photorefractive keratectomy (PRK) for myopia of 6.0 to 10.0 diopters (D) using the Nidek laser and compare them with those in other series, including LASIK, and to analyze the subjective aspects of vision. SETTING: Remuera Eye Clinic, Auckland, New Zealand. METHOD: One hundred ninety-two eyes of 162 consecutive PRK patients with a 6 month follow-up were studied. All had myopia in the range of 6.0 to 10.0 D by spherical equivalent. Astigmatism of up to 3.5 D was treated by laser simultaneously. At 6 months, uncorrected visual acuity, best spectacle-corrected visual acuity, residual refractive error, and corneal haze were recorded. After the 6 month examination, a questionnaire was sent to all patients. RESULTS: Uncorrected visual acuity of 20/20 was achieved in 59% of eyes and of 20/40 or better in 94%. The accuracy of correction was +/- 0.5 D of emmetropia in 77% and +/- 1.0 D in 94%. In 2 eyes (1.0%), corneal haze was assessed as 2+ and 2 Snellen lines of best corrected visual acuity were lost. The questionnaire revealed that 45% of patients had difficulties with night vision. This was better than before surgery in 35% but worse in 31%. Halos were seen around lights by 52%, but these were less than before surgery in 21% and worse in 26%. There was undue sensitivity to glare in 29%, but this was better than before surgery in 19% and worse in 28%. The overall quality of vision was better than before surgery in 60% and worse in 17%. Seventy-seven percent did not need spectacles. Ninety-eight percent said they would have the surgery again. CONCLUSIONS: As long as the patients are informed of the limitations of PRK for myopia, the results are acceptable.

Adolescent↗
PubMed1996

Comparison of photorefractive keratectomy for myopia using 5 mm and 6 mm diameter ablation zones.

BACKGROUND: We compared the 5 mm and 6 mm ablation zones of the Summit Omnimed in the treatment of myopia in 2 eyes of the same patient. METHOD: One hundred and twenty-four consecutive patients with myopia less than 6 diopters (D) has one eye treated with a 5 mm ablation zone and the other eye with a 6 mm ablation zone. Minimum follow up was 6 months. RESULTS: Follow-up was achieved in 101 patients of the total 124. In the 5 mm group 79% achieved 20/30 uncorrected visual acuity while 68% of the 6 mm group achieved 20/30 acuity. Ninety-seven percent of all eyes in both groups achieved 20/40. Some of the disparity between the 20/30 acuity in the two groups is that initial corrections with the 6 mm zones were conservative. Corneal haze was less in the 6 mm group; subjectively they had better night vision. CONCLUSIONS: Both lasers with the different ablation zones gave reasonably predictable correction of myopia of up to -6 D. Overcorrection and corneal haze were less in the 6 mm group and night vision was subjectively better.

Corneal Opacity↗
PubMed1995

Excimer laser surgery for myopia and myopic astigmatism.

Photorefractive keratectomy using the Summit Excimer Laser has been carried out on 1333 eyes with myopia or myopic astigmatism which have been followed up for six months or longer. Of those, 607 have been followed up for one year. Of the eyes with myopia or myopic astigmatism of up to 3 dioptres spherical equivalent, at one year 85.6% had unaided vision of 6/6, 97.2% 6/9 or better, and 99.4% 6/12 or better. Of the eyes between -3.25 and -6.00 dioptres spherical equivalent at one year 72.1% achieved 6/6 vision unaided, 88.8% 6/9 or better, and 94.2% 6/12 or better. Of the eyes between -6.25 and -10.00 dioptres, at one year 49.6% achieved 6/6 vision unaided, 76.1% 6/9 or better and 88.0% 6/12 or better. To achieve these figures, 28% of the patients had astigmatic keratotomy, either two or three weeks before photorefractive keratectomy, or at the same time as photorefractive keratectomy. Photorefractive keratectomy is as predictable as radial keratotomy in eyes of under 6 dioptres myopia, but is more predictable than radial keratotomy in higher myopia. Photorefractive keratectomy has the advantages of leaving an eye which is structurally sound, and without diurnal variation of focusing.

Adult↗
PubMed1990

The management of intraocular foreign bodies.

This study of 69 cases of retained intraocular foreign body confirms that eyes with anterior segment foreign bodies fare better than those with posterior segment foreign bodies, that eyes with smaller foreign bodies fare better than those with larger, and that the magnet is the safest method of removal. There is no evidence to support primary vitrectomy in every case of posterior segment foreign body. Computerised tomography is the best method of localisation, but a foreign body can be missed on computerised tomography, and a plain x-ray is still the best method of detection.

Adolescent↗
PubMed1986

Infection after retinal detachment surgery.

In 250 consecutive retinal detachment operations performed by the author, there were 14 cases (5.6%) of infection of the scleral buckle. The commonest infecting organism was Staphylococcus aureus. The surgery in these infected cases took longer than average, and utilized more than the usual amount of silicone sponge; a higher proportion were reoperations. After an average follow-up of 22 months, only six of the 14 had vision of 6/36 or better and of these, two had persisting inferior traction detachments. On the basis of this study and others, the preferred management of infected scleral buckles is to remove the sponge as soon as the diagnosis is made. The risk of redetachment is a lesser evil than the sequelae of prolonged inflammation which include traction retinal detachment, massive periretinal proliferation, and premacular fibrosis.

Humans↗
PubMed1982

Closed-system intra-ocular surgery: the first six years in Auckland.

The advent of the combined infusion-suction-cutting and illuminating instruments has opened up new possibilities in intra-ocular surgery. Tissue can now be removed from the interior of the eye through small water-tight incisions, with maintenance of the normal ocular pressure during surgery. In the posterior segment of the eye, opaque vitreous can be removed and replaced. In the anterior segment, opacities such as complicated cataracts and fibrous membranes can be removed. We have used this new instrumentation on 81 eyes with a successful outcome in 49 (60 percent).

Eye Diseases↗
PubMed1981

Vitrectomy in the management of endophthalmitis.

Four cases of endophthalmitis were managed with pars plana vitrectomy and intravitreal antibiotics. All four cases made a good structural recovery, but the only cases which regained good vision were the two which had vitrectomy within three days of the first signs of endophthalmitis. The vitreous aspirate in all four cases showed polymorphonuclear leukocytes, but in only one case were organisms cultured. Vitrectomy is a means of removing the bulk of the infected material, of allowing dispersion of intra-ocular antibiotic, of removing membranes which may lead to later traction detachment of the ciliary body or retina, and of clearing the visual pathway. Microbiological diagnosis is best made by culture of vitreous aspirate. Retinal function is affected early in the course of the inflammatory process. Vitrectomy is recommended as the emergency primary treatment of acute endophthalmitis.

Adult↗