Biomedical subjects

Paul D O'Brien

Publications and source records attributed to Paul D O'Brien.

6 recordsLinked to original sources

PubMed2006

Subjective difficulty of each stage of phacoemulsification cataract surgery performed by basic surgical trainees.

PURPOSE: To measure the relative difficulty of each stage of phacoemulsification surgery performed by basic surgical trainees. SETTING: Mater Misericordiae University Hospital, Dublin, Ireland. METHODS: This prospective study comprised 100 consecutive cases of phacoemulsification performed by 8 trainee surgeons over an 11-month period. The trainees completed a questionnaire at the end of surgery, rating the degree of difficulty of 8 individual stages of phacoemulsification on a 5-point scale from 1 (very easy) to 5 (very difficult). RESULTS: At the start of the study, trainees had spent a mean of 9.4 months training. The mean preoperative best corrected decimal visual acuity was 20/70. The most difficult stages were phacoemulsification and capsulorhexis with the highest mean scores of 3.32 +/- 1.00 (SD) and 3.30 +/- 1.24, respectively and the lowest completion rates of 66.7% and 74.4%, respectively. The first 3 stages of peribulbar blockade (1.72 +/- 0.75), draping the surgical field (1.35 +/- 0.70) and corneal incision (1.97 +/- 0.72) were easiest and had close to a 100% completion rate. Hydrodissection, irrigation/aspiration, and intraocular lens insertion had difficulty rates of 2.42 +/- 0.92, 2.80 +/- 1.10, and 2.58 +/- 1.08, respectively, and completion rates of 92.3%, 78.4%, and 83.1%, respectively. Posterior capsule tear occurred in 9%, including 4% with vitreous loss; there was 1 case of zonular dehiscence. CONCLUSIONS: Trainee surgeons found phacoemulsification and capsulorhexis the most difficult stages of cataract surgery early in the learning curve. More time can be dedicated to mastering these steps in the wet lab.

Aged↗

PubMed2005

Visual experiences during vitreous surgery under regional anesthesia: a multicenter study.

PURPOSE: To investigate patients' subjective intraoperative visual experiences during vitreous surgery performed under regional anesthesia, to ascertain if patients were frightened by their visual experiences, and to determine the risk factors associated with a frightening visual experience. DESIGN: Multicenter, prospective study. METHODS: Sixty-five patients who had vitreous surgery under regional (retrobulbar or peribulbar) anesthesia in five centers in Ireland, Singapore, and Hong Kong were interviewed within 2 hours of their operation using a standardized questionnaire. RESULTS: Thirty patients (46.2%) perceived light perception throughout the entire operation, 19 patients (29.2%) experienced transient loss of light perception, and 16 patients (24.6%) experienced no light perception throughout the entire duration of the surgery. Nine patients (13.8%) were frightened by their intraoperative visual experiences. Patients who were frightened by their visual experiences were more likely to see color (100%) than those who were not frightened (55.4%) (P = .010). The mean age of the patients who were frightened was lower (51.8 years) compared with those who were not frightened (64.6 years) (P = .003). The mean duration of surgery was longer for patients who were frightened (118.9 minutes) compared with those who were not frightened (91.2 minutes) (P = .047). CONCLUSIONS: Most patients undergoing vitreous surgery under regional anesthesia retained at least light perception intraoperatively. Importantly, 13.8% of patients were frightened by their visual experiences. A younger age, longer duration of surgery, and perception of color were risk factors for a frightening visual experience.

Adult↗

PubMed2005

Patient pain during stretching of small pupils in phacoemulsification performed using topical anesthesia.

PURPOSE: To assess the pain experienced by patients with small pupils during pupil stretching in phacoemulsification performed using topical anesthesia. SETTING: Royal Victoria Eye & Ear Hospital and Mater Misericordiae University Hospital, Dublin, Ireland. METHODS: This was a prospective study that included 26 eyes with small pupils requiring mechanical pupil stretching during phacoemulsification cataract surgery performed under topical anesthesia without sedation. RESULTS: The mean pain score for the instillation of anesthetic drops (2.02) was higher than the mean pain score for the pupil stretch (1.63), but this difference was not significant (signed rank test = -32; P = .2738). There was no significant correlation between the duration of surgery and the overall pain score (r = 0.345; P = .08). There was no significant correlation between change in pupil size and either the pupil stretch score (r = -0.069; P = .74) or the overall pain score (r = -0.032; P = .8739). CONCLUSIONS: Pupil stretching during phacoemulsification in patients with small pupils was performed with minimal patient-reported pain using topical anesthesia. Stretching small pupils with a mechanical device during phacoemulsification performed under topical anesthesia was a safe procedure and did not result in significant patient discomfort.

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PubMed2005

Does extended wear of a tight necktie cause raised intraocular pressure?

PURPOSE: To investigate the effect that extended wear of a tight necktie has on the intraocular pressure (IOP), measured by Goldmann applanation tonometry in a normal and aged-matched glaucoma group. METHODS: One eye of 18 normal and 19 primary open-angle glaucoma patients was included in this prospective study. The intraocular pressure of each patient's randomly selected eye was measured with the patient dressed in an open shirt collar, again 3 minutes after their collar was fastened and necktie tightened, again after a further 12 minutes, and finally 3 minutes after the necktie was loosened and collar unfastened. The same examiner performed all measurements in a masked fashion. RESULTS: The mean intraocular pressure in the normal group (n = 18) increased by 0.56 mm Hg (P = 0.30) and increased significantly (*) in the glaucoma group (n = 19) by 1.58 mm Hg (P = 0.001*) after tightening the necktie for 3 minutes. The mean IOP then decreased after leaving the necktie on for a further 12 minutes, by 0.89 mm Hg (P = 0.08) in the normal group and decreased significantly by 0.94 mm Hg (P = 0.04*) in the glaucoma group. Finally after loosening the necktie for 3 minutes (immediately after 15 minutes of continuous necktie wear) the mean IOP decreased in the normal group by 0.89 mm Hg (P = 0.02*) but only minimally in the glaucoma group by 0.16 mm Hg (P = 0.72). The patient's age or collar size showed no significant correlation with the change in mean IOP following tight necktie wear. CONCLUSION: A significant increase in IOP after 3 minutes of tight necktie wear occurred only in the glaucoma group, but this increase was followed by a significant decrease in IOP after 15 minutes of tight necktie wear. Avoidance of wearing a tight necktie over an extended period is therefore not necessary in patients with glaucoma.

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PubMed2004

Dry eye: diagnosis and current treatment strategies.

One in four patients attending ophthalmic clinics report symptoms of dry eye, making it one of the most common complaints seen by ophthalmologists. Aqueous-layer deficiency is the most common form of dry eye and is frequently caused by decreased secretion of tears by the lacrimal glands. Evaporative dry eye is often secondary to meibomian gland disease and results in a defective lipid layer. Tear replacement or preservation using artificial tears and/or punctal occlusion are the mainstay of treatment. Newer forms of therapy were designed to modify the underlying disease process. These include the use of topical cyclosporin A, autologous serum, and sodium hyaluronate drops, which suppress underlying inflammation, provide growth factors, and prevent the onset of squamous metaplasia in ocular surface epithelium. Hormonal therapy might have a role in the future of dry eye therapy.

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PubMed2004

Risk factors for endothelial cell loss after phacoemulsification surgery by a junior resident.

PURPOSE: To assess the risk factors for endothelial cell loss after phacoemulsification cataract surgery performed by a junior resident. SETTING: Ophthalmic teaching hospital, Dublin, Ireland. METHODS: This prospective study included 40 eyes having divide-and-conquer phacoemulsification cataract surgery by a junior resident under the supervision of an experienced surgeon. Nine variables were examined to assess the risk for corneal endothelial cell loss postoperatively. RESULTS: The mean overall endothelial cell loss was 11.6%. Longer surgery time, longer absolute and effective phaco time, higher mean ultrasound power, and higher cataract density were significantly associated with endothelial cell loss on univariate analysis. Multivariate analysis identified a grade 3 nucleus (severely dense) and long absolute phaco time as independent predictors for endothelial cell loss, with longer absolute phaco time the stronger predictor. CONCLUSIONS: Divide-and-conquer phacoemulsification cataract surgery was a safe technique in the hands of an ophthalmic trainee. This study supports advice to junior surgeons to choose cases with less dense cataracts as this will help reduce the absolute phaco time and thus minimize endothelial cell loss.

Adult↗