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The role of bifocals in the management of accommodative esotropia
Published in Jan-Tjeerd de Faber, 28th European Strabismological Association Meeting, 2020
Bifocals should be used in patients who are ortophoric for distance, or have a minimal residual esotropia after full cycloplegic correction, and who still have an esotropia for near, which is converted into esophoria with the help of additional plus lenses. In case of amblyopia, or a residual esotropia, in spite of additional plus lenses, bifocals are contraindicated. The smallest additional plus lens that converts the esotropia for near to an esophoria, should be prescribed. It is, however, noteworthy that the bifocal segment is placed properly and high enough to facilitate the child to use it for near work. Although small bifocal segments and progressive glasses are cosmetically attractive, they do not always achieve this goal. Finally, children with bifocal glasses must repeatedly be refracted in cycloplegia and the near addition should gradually be weaned off.
Optics and refractive errors
Published in Mostafa Khalil, Omar Kouli, The Duke Elder Exam of Ophthalmology, 2019
Nemat Ahmed, Omar Kouli, Mostafa Khalil, Obaid Kousha
Methods that may be helpful in slowing myopic progression but there is no strong evidence for any strategy: Use of atropine (lower doses of atropine were more effective with fewer side effects than higher doses [1]) and pirenzepine drops.Outdoor activity: It is thought that too much near work may contribute in myopic progression (2).Bifocals and progressive lenses.
Ophthalmic lenses
Published in Pablo Artal, Handbook of Visual Optics, 2017
The first bifocal lenses were invented by Benjamin Franklin in 1784, by joining in a single ring two half lenses with different focal lengths. Bifocal lenses are made with two different concepts: (1) with two different materials, glasses or plastics having different refractive indices, as in Figure 10.16a and b, or (2) with a single material but with two different curvatures, as in Figure 10.16c and d.
Bilateral Subluxation of Microspherophakic Lens in a Child with Cohen Syndrome
Published in Journal of Binocular Vision and Ocular Motility, 2023
Elizabeth A. Chu, Alexandria Cummings, Nicholas Sala, Nicholas Sala
Prior to the lensectomy OS, a brief EUA was performed primarily in the right eye for refraction. Retinoscopy of the aphakic right eye revealed a +18.50D spherical refractive error. Lensectomy OS was performed with a vitrector, and the patient was again left aphakic with follow-up the next day. On post-op day #1 of lensectomy OS, there was resolving hyphema in the anterior chamber that revealed an iridodialysis superotemporally in the left eye from 11 to 5 o’clock from surgical trauma. As management of iridodialysis typically involves observation and bed rest, the decision was made to monitor the patient. She was seen 3 weeks later, at which point all post-op medications were completed. The patient had improved ability to fix and follow compared to the initial presentation. Intraocular pressures were 10 mmHg OD and 9 mmHg OS using iCare tonometer. There was complete resolution of the hyphema and iridodialysis OS. Retinoscopy revealed +18.50D spherical refractive error OU. Of note, calculated average aphakic refraction in a 5-and-a-half-year-old child is +12.84D.1 Spectacles were prescribed as the patient’s full refractive correction. Bifocal addition was considered but withheld due to the patient’s severe developmental delay.
Blur adaptation: clinical and refractive considerations
Published in Clinical and Experimental Optometry, 2020
Matthew P Cufflin, Edward Ah Mallen
The visual diet presented to the human visual system has undergone considerable change in the last decade, with increasing reliance on handheld devices for work, communication and entertainment. Such devices can expose the eyes to stimuli that differ from natural images in terms of spatial frequency content and chromatic spectrum. This offers the potential of a chronic blur stimulus, which may induce adaptive effects. In the area of myopia management, the role of relative myopic retinal blur as a ‘stop’ signal for eye growth is building in the evidence base of clinical effectiveness. Radhakrishnan et al.2014 examined the effect of simultaneous vision from a bifocal correction. Shifts in the perception of blur were observed with simultaneous vision bifocal designs, and the magnitude of the shifts in perception were related to the proportions of defocus. The impact of chronic exposure to myopic defocus provides considerable opportunity for the study of blur adaptation. It may be the case that blur adaptation has a role to play in the refinement of myopia management strategies.
Optical and pharmacological strategies of myopia control
Published in Clinical and Experimental Optometry, 2018
Earlier studies exploring the influence of bifocal spectacle lenses on myopia progression in children similarly reported minimal impact on myopia progression compared to single vision correction.2000 However, a recent trial of bifocal and prismatic bifocal lenses have demonstrated one of the greatest myopia control effects. This three‐year randomised clinical trial required children to be assigned to one of three treatments: single vision distance correction lenses, executive bifocal lenses with a +1.50 D near addition or executive prismatic bifocals with a 3 PD base‐in correction incorporated into +1.50 D near addition segment of both lenses.2014 After three years of treatment, bifocal lenses reduced myopia progression by approximately 50 per cent compared to the single vision control group. Mean difference in myopia progression between the single vision group and bifocal and prismatic bifocal groups were −0.81 and −1.05 D, respectively (Figure 1).