Refractive surgery

McDonnell, Peter J.

doi:10.1136/bjo.83.11.1257

Cited by 11 publications

(11 citation statements)

References 27 publications

(17 reference statements)

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“…The primary refractive constituents of the eye are the cornea and the crystalline lens. As the surgical correction of ametropia or astigmatism depends on changing the corneal and/or lenticular power of the eye, 19 determining the magnitude of corneal and lenticular astigmatism as well as ocular biometric features is essential in cases of cataract and refractive surgery. In most situations, the amount of lenticular astigmatism is so minimal that it can be disregarded; however, if the amount of lenticular astigmatism is high enough, it should be taken into account to prevent unacceptable final refractive outcomes after cataract or refractive surgery.…”

Section: Discussionmentioning

confidence: 99%

Ocular refractive and biometric characteristics in patients with thalassaemia major

Nowroozzadeh

Kalantari

Namvar

et al. 2011

Clinical and Experimental Optometry

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Background: Thalassaemia major is associated with characteristic findings in craniofacial bony structures and thereby may render abnormal bony orbit and subsequently distinctive ocular biometry. The purpose of the present study was to evaluate the ocular refractive and biometric characteristics in patients with thalassaemia major. Methods: This case-controlled study comprised 94 eyes of 47 patients with thalassaemia major and 88 eyes of 44 age-and sex-matched healthy control subjects. All participants had a complete ocular examination including slitlamp biomicroscopy, fundoscopy, ocular biometry, keratometry, refraction and analysis using Fourier transformation. Results: There were no significant differences in spherical equivalent (p = 0.66) and total astigmatism (p = 0.83) between groups. Mean uncorrected vision and visual acuities (logMar) were similar (p = 0.32 and p = 0.71, respectively). Compared with controls, thalassaemic patients had a shorter axial length (23.01 Ϯ 0.12 [SEM] mm versus 23.46 Ϯ 0.12 mm, p = 0.035), thicker crystalline lens (4.01 Ϯ 0.11 mm versus 3.87 Ϯ 0.1 mm, p = 0.046) and steeper average keratometry (44.02 Ϯ 0.24 D versus 43.44 Ϯ 0.24, p = 0.03). Fifty-seven per cent of thalassaemic patients had against-the-rule astigmatism (total), while 64.6 per cent of controls showed a with-the-rule pattern (p < 0.05). These patterns were also found for corneal astigmatism. The magnitudes of total, corneal and lenticular astigmatism were similar among groups. Regression analysis showed significant correlation between corneal ( J0 and J45) and total ( J0 and J45) astigmatism. The correlations were less prominent between lenticular and total J0 and J45. The mean intraocular pressure was 14.68 Ϯ 0.27 mmHg and 13.3 Ϯ 0.26 mmHg in the thalassaemia and control groups, respectively (p < 0.001). Six eyes (12.8 per cent) of four patients in the thalassaemia group had posterior subcapsular cataract, while the condition had not been observed in controls (p = 0.049). Conclusions: Shorter axial length, thicker lens, steeper corneal curvature and more against-the-rule pattern were characteristic findings in patients with thalassaemia major. Key words: astigmatism, biometry, refraction, thalassaemia major Haemoglobin is essential for normal oxygen delivery to tissues. Betathalassaemia is one of the most common haemoglobinopathies (with an incidence of up to 14 per cent in some populations) and has an autosomal recessive inheritance pattern. In this disorder, abnormalities in b-globin biosynthesis diminish production of haemoglobin tetramers, resulting in hypochromia and microcytosis. Management of thalassaemia major consists of regular long-life blood Functional changes such as abnormalities in the electro-retinogram, the electrooculogram, the visual-evoked potentials and contrast sensitivity function have been demonstrated in these patients. 13Thalassaemia major patients have characteristic skeletal changes, including typical craniofacial changes and deformities of the long bones that result from expansion of t...

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Section: Discussionmentioning

confidence: 99%

Ocular refractive and biometric characteristics in patients with thalassaemia major

Nowroozzadeh

Kalantari

Namvar

et al. 2011

Clinical and Experimental Optometry

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“…First, the dramatic rise in the number of refractive surgeries performed in the United States has drawn increasing numbers of patients to the field of ophthalmology for elective procedures for non-sight-threatening conditions. 7 Second, increased competition in the eye care market has led to a greater appreciation for the need to understand patient desires. 8,9 To learn more about patients' expectations for eye care, we initiated a pilot study using focus groups to determine a relevant set of concerns that patients express as expectations.…”

mentioning

confidence: 99%

Patient Expectations Regarding Eye Care

Dawn

Santiago-Turla²,

Lee³

2003

Arch Ophthalmol

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Background: Increasing emphasis on patient-centered care and other recent developments should make patient expectations increasingly important in ophthalmology. Motivated by the pivotal role of patient expectations in qualityof-care assessments and by the limited knowledge about patients' expectations regarding eye care, we initiated a pilot study using focus groups to determine a relevant set of concerns that patients express as expectations. Methods: A total of 6 focus groups were conducted with patients at Duke University Eye Center (Durham, NC). Focus groups ranged in size from 4 to 10 people. The average group size was 6. Results: Content analysis of transcripts from the 6 focus groups yielded 22 areas of expectations for eye care, which were classified into 5 categories: communication , interpersonal manner, physician's skill, logistics, and other. The 6 areas that appeared to be of greatest importance to focus group participants were the following: (1) honesty, (2) information about diagnosis and prognosis, (3) explanation in clear language, (4) ophthalmologist's experience and reputation, (5) empathy, and (6) listening and addressing concerns. Conclusions: In general, ophthalmology patients in the focus groups emphasized expectations related to communication and interpersonal manner. In contrast to previous studies with primary care patients, however, ophthalmology patients expressed few expectations for technical interventions, such as medication prescriptions, physical examination, or diagnostic testing.

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“…Laser-assisted in situ keratomileusis (LASIK) is still the most widely used technique; it is a painless, safe, and accurate method for treating refractive errors with quick recovery (3)(4)(5) . By preserving epithelial integrity in the central region of the cornea, it promotes a milder wound healing reaction.…”

Section: The Median= 0 Logmar For Both Time Points (P= 0424) For Spmentioning

confidence: 99%

“…Pallikaris was the first to promote the removal of corneal stromal tissue with excimer laser to correct refractive errors (2) . The use of excimer laser to correct myopia, hyperopia and astigmatism evolved in recent years, mainly due to the technological advancement of devices.Laser-assisted in situ keratomileusis (LASIK) is still the most widely used technique; it is a painless, safe, and accurate method for treating refractive errors with quick recovery (3)(4)(5) . By preserving epithelial integrity in the central region of the cornea, it promotes a milder wound healing reaction.…”

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confidence: 99%

Fluência do laser e tempo de parada cirúrgica, por perda de fixação, como fatores relacionados à precisão refracional

Lucena¹,

Andrade

Lucena³

et al. 2013

Rev. bras.oftalmol.

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Objective: To evaluate the correlation of flow and stopping time intraoperative loss of attachment factors as hypertension or hipocorreções of refractive errors after Lasik. Methods:The age ranged between 19 and 61 years (mean= 31.27 ± 9.99 (mean= 0.23 ± 0.69) and postoperative uncorrected 0.40-0 (x= 0.30 ± 0, 68). (mean= 0.545 ± 0.01), p = 0.762) between the flow and spherical equivalent (mean = -0.04 ± 0.38) in eyes operated. The minimal downtime during surgery was 02 seconds and maximum was 12 seconds (mean= 4.90 ± 3.47). Making a correlation (r = 0.08865, p = 0.411) p=0,424). No equivalente esférico pré e pós-operatório, notou-se uma óbvia diferença (p< 0,0001), no pré-operatório com média de -4,09 ± 2,83 e o pós com média de -0,04 ± 0,38. A mediana foi de -4,75 no pré e de 0 no pós-operatório. Sessenta e nove casos (78,3%) ficaram plano ± 0,25. A fluência mínima foi de 0,513 mJ/cm 2 e a máxima de 0,581 mJ/cm 2 com média de 0,545 ± 0,01, não se percebendo correlação (r= -0,03266; IC 95% -0,241 a 0,178; p= 0,762) entre a fluência e o equivalente esférico final (média= -0,04 ± 0,38) nos olhos operados. O tempo mínimo de parada transoperatória foi de dois segundos e o máximo de 12 segundos com média de 4,90 ± 3,47. Fazendo-se uma correlação (r= 0,08865; IC 95%= -0,123 a 0,293; p= 0,411) entre o equivalente esférico pós-operatório e o tempo de parada transoperatória, não se percebeu diferenças. Conclusão: Não houve correlação entre a fluência do laser e o tempo de parada transoperatória por perda de fixação, com hiper ou hipocorreções nas ametropias pós-Lasik. The Median= 0 logMAR for both time points (p= 0.424). For spherical equivalent before and after surgery, we found an obvious difference, with the pre (mean= -4.09 ± 2.83) and post (mean= -0.04 ± 0.38). The Median was -4.75 in the pre and zero postoperatively (p <0.0001). Sixty-nine cases (78.3%) were plan ± 0.25. Fluency minimum= 0.513 mJ/cm2 and maximum= 0.581 mJ/cm2Descritores (1) . Pallikaris was the first to promote the removal of corneal stromal tissue with excimer laser to correct refractive errors (2) . The use of excimer laser to correct myopia, hyperopia and astigmatism evolved in recent years, mainly due to the technological advancement of devices.Laser-assisted in situ keratomileusis (LASIK) is still the most widely used technique; it is a painless, safe, and accurate method for treating refractive errors with quick recovery (3)(4)(5) . By preserving epithelial integrity in the central region of the cornea, it promotes a milder wound healing reaction. The healing response triggered by the laser and the creation of a flap are important to the safety and efficacy of the procedure. However, it is a significantly complex event (6) . The literature reports great refractive stability from the 3 rd month after surgery (7)(8)(9) . However, do intraoperative factors such as daily variations in laser fluence and interruptions during laser application due to loss of fixation influence the refractive outcome?The aim of this study was to ev...

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Refractive surgery

Cited by 11 publications

References 27 publications

Ocular refractive and biometric characteristics in patients with thalassaemia major

Ocular refractive and biometric characteristics in patients with thalassaemia major

Patient Expectations Regarding Eye Care

Fluência do laser e tempo de parada cirúrgica, por perda de fixação, como fatores relacionados à precisão refracional

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