Search PubMed⌕ Search

Biomedical subjects

H Maclean

Publications and source records attributed to H Maclean.

At least 19 recordsLinked to original sources
PubMed2005

Enucleation with reverse replacement of sclera as an alternative to conventional evisceration.

BACKGROUND AND OBJECTIVE: To objectively review the results of a technique combining enucleation with evisceration in patients listed for traditional evisceration with preservation of the rectus muscles. MATERIALS AND METHODS: Ten patients who underwent combined enucleation and evisceration with 3 to 36 months of follow-up were identified (average follow-up 14 months). Three eyes were phtihisical, 1 microphthalmic, 1 buphthalmic, 1 a secondary implant following conventional evisceration and 4 non-phtihisical painful eyes. The technique involved enucleation followed by evisceration of the eye contents. Implants, either coral or acrylic, were wrapped in the eviscerated sclera and replaced in the orbit with the posterior pole of the sclera facing anteriorly. The rectus muscles were then resutured onto the sclera. The patients were subsequently recalled and volume replacement, cosmesis and complications were assessed. RESULTS: Three coral and 7 acrylic implants were placed, 2 of 22 mm, 7 of 20 mm and 1 of 18 mm. No complications were encountered, in particular no implant extrusions. Cosmesis was graded good in 9 out of 10 patients. CONCLUSION: Combined enucleation and evisceration allows the selection and placement of an appropriately large-sized implant to achieve good volume replacement with no extrusions in our series. This technique is particularly pertinent as an alternative to standard evisceration in phtihisical eyes.

Adolescent↗
PubMed2001

Origins of the desire for euthanasia and assisted suicide in people with HIV-1 or AIDS: a qualitative study.

BACKGROUND: Euthanasia and assisted suicide, and policies to address them are the subjects of contentious debate in many countries. However, the question of why people desire euthanasia or assisted suicide has not been coherently answered. We aimed to answer this question in a specific group of patients. METHODS: We did a qualitative study of 32 people with HIV-1 or AIDS, who were enrolled in the HIV-1 Ontario Observational Database at Sunnybrook and Women's College Health Sciences Centre, Toronto, Ontario, Canada. We elicited participants' experiences of deliberation about euthanasia or assisted suicide, and the meaning of these experiences with in-depth, face-to-face interviews. We analysed our data with grounded theory methods. FINDINGS: Participants' desire for euthanasia and assisted suicide were affected by two main factors: disintegration, which resulted from symptoms and loss of function; and loss of community, which we defined as progressive diminishment of opportunities to initiate and maintain close personal relationships. These factors resulted in perceived loss of self. Euthanasia and assisted suicide were seen by participants as means of limiting loss of self. INTERPRETATION: These determinants of desire for euthanasia or assisted suicide in people with HIV-1 or AIDS have implications for the debate on these practices, and development of policies to regulate them.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Variability in digital assessment of cortical and posterior subcapsular cataract.

To identify validity of the standardised Nidek EAS-1000 retroillumination image analysis, images of 450 consecutive patients were analysed for the standard 6.5 mm and for the maximal pupil size. The software allows for separation of cortical and posterior subcapsular opacities and defines threshold for cataract automatically at 12% below the brightest point of the histogram of pixel luminescence. The results were compared with clinical Wilmer cataract grading. Correlation between clinical and digital assessment was 0.48* for cortical opacities in maximal pupil size, 0. 47* in 6.5 mm pupil size analyses, and 0.71* for posterior subcapsular opacities (*p < 0.001). In 24.6% of maximal pupil size analyses and in 11.7% of standard pupil size analyses standardisation revealed confounding features, such as other opacities of media, refractive shadows etc., that masqueraded as cataract and interfered with the cortical opacity measurements. Automatic standardized analysis has reduced many sources of observer variation (level of illumination, pupil size and threshold adjustment), but the revealed range of confounding opacities and artifacts still requires observer interpretation.

Aged↗
PubMed1998

[A simplified screening test for the identification of individuals with diminished vision in developing countries].

Simple but effective tests have been produced for screening subjects with low vision in developing countries. These tests of distance and near vision, based on the E test, were evaluated and validated in trials with people aged 4-90 years, and have been field tested in the health, education and rehabilitation services in 32 developing countries. Their sensitivity and specificity as screening tools for low vision have been calculated: sensitivity of 85% and specificity of 96% for the distance vision test, and sensitivity of 100% and specificity of 84% for the near vision test. The content and format of the tests have been demonstrated to be appropriate for developing countries, and their effectiveness for screening for low vision has been confirmed.

Adolescent↗
PubMed1997

Patient comfort during cataract surgery with modified topical and peribulbar anesthesia.

PURPOSE: To evaluate patient comfort during cataract surgery performed using modified topical and peribulbar anesthesia. SETTING: Sunderland Eye Infirmary Cataract Treatment Centre, Sunderland, United Kingdom. METHODS: In this prospective study, 50 consecutive patients scheduled for cataract surgery with local anesthesia were randomly assigned to receive topical bupivacaine hydrochloride plus 0.1 mL subconjunctival lignocaine or standard peribulbar anesthesia. All surgery was performed by one surgeon using a scleral pocket bimanual phacoemulsification technique. Patients were asked to grade the pain experienced during administration of the anesthetic and during cataract surgery using a visual analog scale. RESULTS: No statistically significant difference in patient comfort was demonstrated between the two groups during cataract surgery (P < .4, Wilcoxon rank-sum test), and all patients were satisfied with the anesthesia. However, administration of topical bupivacaine was significantly less painful than peribulbar injections (P < .001, Wilcoxon rank-sum test). In eight patients in the topical anesthesia group, the cataract in the fellow eye was removed using peribulbar anesthesia; seven of these patients stated a preference for the modified topical method, while one patient thought there was no difference between the two methods. There was no difference between the groups in surgical complications, but 24% of the peribulbar group had a minor subconjunctival hemorrhage at the needle entry site. CONCLUSION: The modified topical technique provided satisfactory patient comfort during cataract surgery; it was comparable to the comfort achieved using peribulbar injections. The speed and ease of administering topical anesthesia coupled with the rapid visual recovery after surgery makes this method a suitable and safe choice for day-case phacoemulsification cataract surgery.

Administration, Topical↗
PubMed1997

A computer-generated test of acuity for multi-handicapped children.

Assessment of visual function in severely intellectually handicapped children is difficult but necessary for educational purposes. The difficulties encountered include: lack of literacy skills; lack of verbal and fine motor skills; and low interest level of the optotypes. A computer-generated test has been developed that helps overcome these difficulties. This test presents pictures equivalent in line width to Snellen, which are manipulated on screen to provide movement and change of size to facilitate non-verbal responses and to increase interest level. Evaluation trials were conducted with 96 cognitively normal children and 37 multi-handicapped children. The computer test facilitated testing of significantly more of the multi-handicapped children. Data from both trial groups indicated a good positive correlation between the computer test and a standard optotype test. Further refinement and evaluation of this computer test is continuing.

Adolescent↗
PubMed1996

Squamous cell carcinoma of the eyelid and the acquired immunodeficiency syndrome.

PURPOSE: We studied a case of squamous cell carcinoma of the eyelid in a 42-year-old homosexual man with the acquired immunodeficiency syndrome (AIDS) to explore the link between squamous cell carcinoma and human Papillomavirus infection. METHOD: A rapidly growing, 3-mm lesion was removed from the right lower eyelid by excisional biopsy. RESULTS: Examination of the lesion confirmed squamous cell carcinoma. Polymerase chain reaction for human Papillomavirus 16 was positive. CONCLUSION: This case suggests a role for human Papillomavirus infection in the cause of squamous cell carcinoma in AIDS patients.

AIDS-Related Opportunistic Infections↗
PubMed1996

AIDS and the eye. A 10-year experience.

BACKGROUND: The AIDS database at Fairfield Hospital, Melbourne, maintains information on eye pathology as identified by the three visiting ophthalmologists. Patients underwent an eye consultation: if they had ocular symptoms; if signs were seen on direct ophthalmoscopy by physicians; or when their CD4+ve cell count fell below 50/microL. The first AIDS-associated eye signs were identified in mid-1984. In the subsequent decade, 3257 patients in Victoria tested positive for HIV, and 845 of the 1123 who developed AIDS were treated at Fairfield Hospital. METHODS: We undertook a retrospective review of the Fairfield Hospital database to identify the AIDS-associated ocular problems seen. RESULTS: Some 723 patients had an eye consultation. In the earliest stage of HIV infection, minor non-specific ophthalmic involvement may occur. As the disease progresses, microvasculopathy (cottonwool spots and haemorrhages) appears. External disease also occurs such as molluscum contagiosum and Kaposi's sarcoma of the conjunctiva. With more suppression of the immune system, opportunistic infections become common, and have a considerable visual morbidity. Cerebral toxoplasmosis (117 patients) is only rarely associated with ocular involvement (three patients), but cytomegalovirus (CMV) commonly causes retinitis [204 patients (24%)]. It has been the AIDS-defining illness in 26 patients. A majority had the disease confined to one eye. Mean CD4 cell count at onset is 15 +/- 5 microL and it has been associated with a viraemia in all but two patients. Late complications of CMV retinitis include relapse in 41 (20%), spread to the other eye in 24 (12%), and retinal detachment in 30 (15%). Visual impairment follows from retinal destruction, optic nerve involvement, and retinal detachment. CONCLUSION: The ophthalmic workload from late ocular complications of AIDS is increasing. Newer and more effective methods of treatment are being developed. Ophthalmologists are becoming more aware of the need for universal precautions to avoid risks from this and other blood-borne infections.

AIDS-Related Opportunistic Infections↗
PubMed1996

Excimer phototherapeutic keratectomy for recurrent granular dystrophy.

PURPOSE: Corneal grafting is a standard treatment for visually disabling granular dystrophy. The visual results of this procedure are generally good, but can be marred by recurrences of granular deposits some years later. We report the results of phototherapeutic keratectomy (PTK) for recurrent granular dystrophy in three eyes from two patients and discuss the possibilities of treating de novo granular dystrophy with excimer laser. METHODS: The records of two patients (three eyes) treated with excimer PTK for recurrent granular deposits on the donor cornea were reviewed. RESULTS: In all cases visual acuity was improved and repeat corneal grafting avoided. No significant complications occurred although one eye had further recurrence of granular deposits which was also successfully retreated with excimer PTK. Follow-up on these cases varies between five months and three years. CONCLUSIONS: We believe that excimer PTK offers a simple, safe and repeatable way of restoring visual acuity to most cases of recurrent granular dystrophy. Visual recovery is fast and all the incumbent problems of repeat grafting are avoided.

Cornea↗
PubMed1996

Measured changes in cataract over six months: sensitivity of the Nidek EAS-1000.

Lens opacities in 98 eyes from 63 consecutive outpatients with cataract were recorded by both retroillumination and Scheimpflug slit methods by one operator. This was repeated at 26 +/- 1 weeks. Image analysis used the EAS-1000 software. Cortical and posterior subcapsular (PSC) cataracts were measured in retroillumination images as density more than 14 cct units below background density. Linear densitometry of white scattered light along the optical axis was measured for slit images by both peak density and mean density ('area under the curve'). Retroillumination images showed no discernible change over 6 months (the regression coefficient being as for the intersession reliability). Half of the Scheimpflug slit images could not be analysed because overlying cortical changes masked the more posterior parts of the lens. The other 49 eyes showed a significant increase in nuclear white scatter after 6 months, with greater degrees of change occurring in those eyes with the greatest amount of nuclear cataract initially. This is reflected by the decreased intraclass correlation coefficient (R = 0.42). The area of lens showing greatest change was the anterior fetal nucleus. The Nidek EAS-1000 is able to detect changes over a 6-month period in nuclear density but not in cortical or PSC cataract. The rate of progression of nuclear white scatter increases as the lens opacity becomes more dense. The ability to detect change in cataract over 6 months has implications for epidemiological studies and for trials of anti-cataract drugs.

Cataract↗
PubMed1996

A simplified screening test for identifying people with low vision in developing countries.

Simple but effective tests have been produced for screening subjects with low vision in developing countries. These tests of distance and near vision, based on the E test, were evaluated and validated in trials with people aged 4-90 years, and have been field tested in the health, education and rehabilitation services in 32 developing countries. Their sensitivity and specificity as screening tools for low vision have been calculated; sensitivity of 85% and specificity of 96% for the distance vision test, and sensitivity of 100% and specificity of 84% for the near vision test. The content and format of the tests have been demonstrated to be appropriate for developing countries, and their effectiveness for screening for low vision has been confirmed.

Adolescent↗
PubMed1995

Fetal tissue transplantation and abortion decisions: a survey of urban women.

OBJECTIVE: To describe women's attitudes and predicted behaviour regarding the potential for fetal tissue transplantation (FTT) to influence abortion decisions. DESIGNS: Self-administered questionnaire survey by mail. SETTING: Academic family practice in Toronto. PARTICIPANTS: Random sample of 475 women 18 to 40 years of age selected from the family practice registry of an urban teaching hospital. Family physicians were blind to their patients' participation, and investigators were blind to the subjects' identity. Forty questionnaires were undeliverable. Of the remaining 435, 272 (62.5%) were completed. Six of the women were over 40 years of age or did not indicate their age and were excluded, which left 266 (61.1%) questionnaires for analysis. OUTCOME MEASURES: Number of women who would (a) be more likely to have an abortion if they could donate tissue for FTT and (b) feel better or worse about choosing abortion if FTT were an option, and open-ended comments about the potential for FTT to influence abortion decisions. RESULTS: Of the 266 respondents 32 (12.0%) reported that they would be more likely to have an abortion if they could donate tissue for FTT, 178 (66.9%) stated that they would not be more likely to do so, and 56 (21.1%) were uncertain. Of the 122 who indicated that they would consider an abortion if they were pregnant, 21 (17.2%) stated that they would be more likely to have an abortion if they could donate tissue for FTT, 77 (63.1%) replied that they would not be more likely to do so, and 24 (19.7%) were uncertain. The women 25 to 33 years of age were more likely to be influenced by FTT than the younger or older women, and the women 18 to 24 years were more uncertain about the influence of FTT on abortion decisions than the older women. In written responses some of the women felt that FTT might make abortion decisions easier; many were troubled that FTT might be used to justify a morally problematic abortion decision and felt that FTT should not be used to justify abortion. CONCLUSION: The data, the first of their kind gathered from from women, suggest that some women's abortion decisions may be influenced by the option to donate tissue for FTT. Further research is necessary to explore the mechanism of influence.

Abortion, Induced↗