Delhi Journal of Ophthalmology

Predictors of Unwanted Prismatic Effect Among Bespectacled Symptomatic Ammetropes (Refractive Error Less Than 4D) With Displaced Optical Centre

Babitha Valiyaveettil, Padma B. Prabhu, Asmin P.T., Raju Kuzhippally Vallon 
Department of Ophthalmology, Govt Medical College, Kozhikode, Kerala, India

Editor-in-Chief, Delhi Journal of Ophthalmology, Dr R.P.Centre, AIIMS.

Corresponding Author:

Babitha Valiyaveettil MS
Assistant Professor, 
Department of Ophthalmology, 
Govt Medical College, Kozhikode, Kerala, India
Email Id: 

Received: 07-JUL-2017 Accepted: 29-NOV-2017 Published Online: 01-MAR-2018

Aim and objectives:- This study tries to estimate the relationship between alignment of spectacle, decentration, spherical equivalent and type of lens with induced prism in spectacles.

Design:- Descriptive cross sectional study.

Materials and Methods:- Symptomatic cooperative ammetropes, using spectacles and between the age of 10 and 70 years were included in this study. Induced prism in spectacles were calculated by the Prentice formula. 

Results:- The study group included 29 ammetropic patients having asthenopic symptoms while using spectacles. 65.52% (n=19) were females. The mean age of this group was 48.33 years, with a SD of ± 17.45. This study showed a statistically significant positive correlation between spherical equivalent and induced prism and there is no significant correlation between decentration and induced prism. 

Conclusion:- Spherical equivalent is considered as an important factor affecting the induced prism rather than decentration and alignment problem. 

Keywords :Induced prism, spherical equivalent, decentration