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Bulgarian Review of Ophthalmology

Investigation of the functional vision of low-vision children after long-term visual rehabilitation

Ivelina Pitakova, Zornitsa Zlatarova



According to the definition of WHO, blind children aged 0 to 15 years are those with the best corrected visual acuity of the better eye being less than or equal to 0.1 (6/60). For severe visual disability in children, the corrected visual acuity of the better eye is less than or equal to 0.3 (6/18). For visually impaired children the term visual aid is used, and for adults - visual rehabilitation.


The aim of this article is to study the functional vision of children from the school for the blind “Prof. Dr. Ivan Shishmanov” – Varna, assessing the effect of long-term specialized training and visual rehabilitation.

Materials and Methods

The children from the specialized school for blind “Prof. Dr. Ivan Shishmanov” – Varna were studied in 2009 and 2018. During the initial study 23 children were examined and in 2018 the children were 16. The visual acuity and the objective state of the eye were examined at the first visit. During the second one, in addition to visual acuity, we checked functional vision through a specially developed and adapted questionnaire. Low vision rehabilitation in the school is provided by auxiliary magnification devices.


At the first visit in 2009, a total of 23 children from grades 1–3 were examined. During the second visit in 2018, 16 students were examined. There were five children with one-eye blindness and 18 with low vision in both eyes. Ten children were recommended for visual aids through a magnifier, six were targeted for correction with dioptric glasses, for four only Braille was possible, and three did not get any specific recommendation, as they did well without aids, according to the visual therapist. Nine years later, it was found that eleven children used a magnifier, seven of them using a magnifying glass and an electronic magnifier, and only one child used dioptric glasses and a magnifier. The remaining three children used a magnifying glass. The most preferred magnification was 5x, used by six children (37.5%). Three students learned only be means of Braille. The assessment of functional vision showed positive development of near vision skills. The students held the optical devices correctly in 93.75% of the cases and recognized a face in 81.25%. The evaluation of the activities at distance showed 100% success in climbing stairs. Additional training with a magnifying device is still need in 50 %. In 12.5% of the cases the aid device was completely rejected.


Our study found that most of the children with visual impairment in the school had enough useful sight capacity. The learning of Braille was often combined with the flatbed font, in addition to enlarged or bigger-sized fonts on optical or electronic devices. All students in the specialized school knew Braille, but a large part of them also use the flatbed fonts. Their high motivation to cope with magnifying devices coincided with their good adaptation and developed skills. This confirms the effective need for visual rehabilitation also for children as early as possible.


childhood blindness, visual rehabilitation, Braille, magnifier, visual aids, functional vision

Full Text


Lea Hyvärinen. Understanding paediatric low vision, WHO 2003. Available at:

Steinkuller PG, Du L, Gilbert C, Foster A, Collins ML, Coats DK. Childhood blindness. J AAPOS. 1999;3(1):26–32.

Gerinec A, Chynoranský M, Smyková T. Causes of blindness and low vision in children in Slovakia. Cesk Oftalmol. 1990; 46(2):121–7.

Aleksieva G, Popova A, Dimitrova L, Chernodrinska V. Dynamics of clinical forms, cause of pedagogical blindness in children from school for visually impaired. Bulgarian Rev Ophtalmol. 2001; 2:53-7.

Vassileva P, Kirilova Y. SI. Childhood blindness in Eastern Europe. Abstract book WOC 2012.

Dougherty BE, Flom RE, Bullimore MA. An evaluation of the Mars Letter Contrast Sensitivity Test. Optom Vis Sci. 2005; 82(11):970–5.

Kamei-Hannan C. Reading connections : strategies for teaching students with visual impairments. AFB Press; 2015.

Knapp A. N. Bishop Harman, M.B. 1869—1945. Arch Ophthalmol. 1945;34(4):336. doi:10.1001/archopht.1945.00890190338012.

Barraga N. ED014166. 1964; Available from:

Radulov V. 2004. Pedagogy of the visually impaired. Sofia; 2004

Finger RP, Fenwick E, Marella M, Dirani M, Holz FG, Chiang PPC, et al. The impact of vision impairment on vision-specific quality of life in Germany. Investig Ophthalmol Vis Sci. 2011; 52(6):3613–9.

Radulov, V. MC-A. Psychology of the visually impaired. 2011, SIC Phenomenon, pp. 38-107

Pattillo ST, Heller KW, Smith M. The impact of a modified repeated-reading strategy paired with optical character recognition on the reading rates of students with visual impairments. J Vis Impair Blind. 2004; 98(1):28–46.

Toussaint KA, Tiger Jh. Teaching early Braille literacy skills within a stimulus equivalence paradigm to children with degenerative visual impairments. J Appl Behav Anal. 2010; 43(2):181–94. doi: 10.1901/jaba.2010.43-181.

Muranaka Y, Nuruta F, Aoki S, Gohke K. Use of the simplified color video magnifier by young children with severely impaired vision. J Vis Impair Blind. 1984; 79(9):391–5.

Chavda S, Hodge W, Si F, Diab K. Low-vision rehabilitation methods in children: A systematic review. Can J Ophthalmol. 2014;49(3):e71-3. doi: 10.1016/j.jcjo.2014.03.011.

Farmer J, Morse SE. Project Magnify: Increasing reading skills in students with low vision. J Vis Impair Blind. 2007;101(12):763–8.

Mcleish E. A study of the effect of letter spacing on the reading speed of young readers with low vision. Br J Vis Impair. 2007; 25(2):133–43.

Zammitt N, O’Hare A, Mason J, Elliot G. Use of low vision aids by children attending a centralized multidisciplinary visual impairment. J Vis Impair Blind. 1999; 3:351–9.



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About The Authors

Ivelina Pitakova
Eye Clinic “St. Nikolay Chudotvorets”, Varna


Zornitsa Zlatarova
Medical University of Varna

Department of Ophthalmology and Visual Sciences, Faculty of Medicine

Specialized Eye Hospital-Varna