PEDIATRICS Do bifocals reduce accommodative amplitude in convergence excess esotropia? Michela Fresina & Costantino Schiavi & Emilio C. Campos Received: 24 January 2010 / Revised: 10 May 2010 / Accepted: 14 May 2010 / Published online: 4 June 2010 # Springer-Verlag 2010 Abstract Background As therapy with bifocal lenses can generate a condition of acquired hypo-accommodation, we assessed the results of bifocal therapy in children with non-refractive accommodative esotropia in whom near point of accom- modation (NPA) was measured before the prescription of the lenses and at the end of the study. Methods We examined 28 consecutive patients orthophoric for far, but with esotropia due to excess convergence for near (group 1), and 28 matched controls, orthophoric for far and near (group 2). The patients were prescribed bifocal lenses between the age of 5 and 8. The NPA was measured at time zero and after 4 years of follow-up in both groups. Results NPA values, measured at time 0, were lower than average (10 dioptres) in ten of the 28 patients in group 1, and increased over the 4 years of follow-up without exceeding 10 dioptres. Only one of the other 18 patients in group 1, with normal NPA, had a lower value at the end of the study, although the values were still above 10 dioptres. Conclusions In several patients, excessive convergence is secondary to the extra accommodative effort required due to the presence of a primitive NPA deficit. In these subjects, the prognosis can be made on the basis of NPA measure- ment, and treatment with bifocal lenses will always be required to compensate. Furthermore, the parents of these small patients should be informed, even before the prescription of bifocals, that prospective surgery of medial rectus muscles will not eliminate the need for bifocals. Keywords Bifocals . Near point of accommodation . Non- refractive accommodative esotropia Introduction Non-refractive accommodative esotropia is characterized by excessive convergence for near which is unrelated to the refractive error [1–3]. Convergence excess esotropia is caused by a high accommodative convergence and accommodation ratio (AC/A), usually 5 or above [1], in the presence of a normal near point of accommodation (NPA). Th near point of accommodation is that part of space conjugate to the retina during the visual process, when maximum accommodation is exerted, i.e., the closest point which the eye can focus on. There are considered to be two types of convergence excess esotropia. One is due to high AC/A ratio, and the other is due to excessive convergence in response to reduced NPA (hypo-accommodation). Patients with non-refractive accommodative esotropia are usually prescribed bifocal lenses, after cycloplegic refraction, with total correction in the far lens and an addition of a sphere of +3 dioptres [4] in the near lens. Since in these cases the maintenance of binocular vision is impeded by near deviation secondary to excess convergence caused by accommodative effort, bifocal lenses eliminate the need for near accommodation. Some ophthalmologists prescribe progressive lenses, The study was performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki. All persons gave their informed consent prior to their inclusion in the study. M. Fresina : C. Schiavi : E. C. Campos Ophthalmology Service, Department of Surgery and Anaesthesiology, University of Bologna, Bologna, Italy M. Fresina (*) Clinica Oculistica dell’Università, Via Palagi, 9, 40138 Bologna, Italy e-mail: michela.fresina@libero.it Graefes Arch Clin Exp Ophthalmol (2010) 248:1501–1505 DOI 10.1007/s00417-010-1418-6