Publications by authors named "Mythili Natkunarajah"

3 Publications

  • Page 1 of 1

Patient Perception and Emotional Disturbance in Out-of-Hour Ophthalmic Emergency Care.

Semin Ophthalmol 2017 21;32(5):559-563. Epub 2016 Jun 21.

a Accident and Emergency Department , Western Eye Hospital, Imperial College Healthcare NHS Foundation Trust , London , UK.

Purpose: To investigate patient's perception of the severity of their symptoms, reasons for attending an ophthalmic emergency department (ED) out of hours, and to review the prevalence of anxiety and depression.

Methods: We carried out a prospective analysis of the cases presenting out of hours (8:30 PM to 8:30 AM) over a four-month period. We also conducted two questionnaire studies. First, patient's perception of the severity of their symptoms (graded from 1-10). A score of 7 or above was defined as significant. A second questionnaire study used the Hospital Anxiety and Depression Scale (HADS), with a maximum score of 21. Patients who scored between 7-10 points on either anxiety or depression scales are defined as borderline; above 10 as pathological.

Results: A total of 1,531 patients attended the out-of-hours service. The most common diagnoses were trauma (22.8%), infective conjunctivitis (10.2%), and contact-lens-related problems (6.6%). Of 175 completed questionnaires, worry about sight impairment and pain were the most common concerns for attendance. A total of 91% of patients believed their conditions were emergencies that require medical review within 24 hours. 127 HADS questionnaires were completed, showing that 18.9% and 15.0% of patients were suffering from borderline and pathological anxiety, respectively, with a mean HADS-A score of 6.5, SD=3.9. The prevalence of possible and pathological depression was 14.2% and 6.3%, mean=4.9 (SD=3.6). There was no statistical significance difference of score with the time of patient presentation.

Conclusion: The prevalence of anxiety and depression is relatively high in patients who attended the ophthalmic ED and awareness of psychological impact should be raised amongst healthcare professionals.
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December 2017

Subretinal delivery of adeno-associated virus serotype 2 results in minimal immune responses that allow repeat vector administration in immunocompetent mice.

J Gene Med 2009 Jun;11(6):486-97

Division of Molecular Therapy, UCL Institute of Ophthalmology, London, UK.

Background: Adeno-associated virus serotype 2 (AAV2) vectors show considerable promise for ocular gene transfer. However, one potential barrier to efficacious long-term therapy is the development of immune responses against the vector or transgene product.

Methods: We evaluated cellular and humoral responses in mice following both single and repeated subretinal administration of AAV2, and examined their effects on RPE65 and green fluorescent protein transgene expression.

Results: Following subretinal administration of vector, splenocytes and T-cells from draining lymph nodes showed minimal activation following stimulation by co-culture with AAV2. Neutralizing antibodies (NAbs) were not detected in the ocular fluids of any mice receiving AAV2 or in the serum of mice receiving a lower dose. NAbs were present in the serum of a proportion of mice receiving a higher dose of the vector. Furthermore, no differences in immunoglobulin titre in serum or ocular fluids against RPE65 protein or AAV2 capsid between treated and control mice were detected. Histological examination showed no evidence of retinal toxicity or leukocyte infiltration compared to uninjected eyes. Repeat administration of low-dose AAV.hRPE65.hRPE65 to both eyes of RPE65(-/-) mice resulted in transgene expression and functional rescue, but re-administration of high-dose AAV2 resulted in boosted NAb titres and variable transgene expression in the second injected eye.

Conclusions: These data, which were obtained in mice, suggest that, following subretinal injection, immune responses to AAV2 are dose-dependent. Low-dose AAV2 is well tolerated in the eye, with minimal immune responses, and transgene expression after repeat administration of vector is achievable. Higher doses lead to the expression of NAbs that reduce the efficacy of repeated vector administration.
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June 2009

Biometry and formula accuracy with intraocular lenses used for cataract surgery in extreme hyperopia.

Am J Ophthalmol 2007 Jun;143(6):920-931

Moorfields Eye Hospital, City Road, London, United Kingdom.

Purpose: To audit intraocular lens (IOL) power predictions for cataract surgery in extreme hyperopia and to compare the accuracy across different biometry formulae and IOL types.

Design: A retrospective analysis of 76 eyes from 56 patients undergoing cataract surgery with IOLs ranging in power from 30 to 35 diopters (D).

Methods: Axial lengths, corneal powers and anterior chamber depths were measured with ultrasound or optical methods, and the IOLMaster (Carl Zeiss Meditech, Inc, Dublin, California, USA) software was used to predict the refractive outcome for each IOL used. Differences between the predicted and actual postoperative refraction were then analyzed for each formula.

Results: In practice, 55% of patients were within +/-1.0 D of the refraction predicted by their surgeon. In theory, the Haigis formula would have given the smallest mean refractive error (+0.51 +/- 0.12 D), followed by the Hoffer Q (-0.70 +/- 0.14 D), Holladay 1 (-1.11 +/- 0.13 D), and SRK/T formulae (-1.45 +/- 0.14 D). The Haigis formula overpredicted the lens power required, which would have generated a myopic result. The other formulae underpredicted the lens power required and would have generated a hyperopic result. There was a significant difference between lens designs: the Haigis was more accurate for open-loop, whereas the Hoffer Q was more accurate for plate-haptic lenses. The anterior chamber depth measurement could also be used to predict changes in intraocular pressure after surgery.

Conclusion: This represents the largest published series to date of biometry predictions for cataract surgery in extreme hyperopia and confirms the Haigis formula to be the most accurate. A consistent difference between open-loop and plate-haptic lenses suggests that haptic design may influence the effective lens position in very small eyes. We further propose a simple formula to optimize the Haigis and Hoffer Q formulae in patients with extreme hyperopia.
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June 2007