IOBA | Optometry Research Group of the IOBA Eye Institute of the University of Valladolid

We are Calculens

What We Do
about-calculens

About Calculens

CALCULENS.com is an on line tool to support Contact Lens Practitioner in contact lenses fitting procedure. This tool helps during the fitting procedure of soft and gas permeable contact lenses (spherical and toric) even in cases of irregular cornea due to keratoconus, because with CALCULENS.com is simple to know the first diagnostic lens parameters, reducing practitioner chair time and patients visits.
Moreover, CALCULENS.com allows to improve practitioner’s experience with the possibility to save the fitting procedures, helping to achieve the professional training necessary to fit and prescribe all type of contact lenses with confident.

Contact lens fitting calculator

You can calculate the parameters of soft contact lenses; gas permeable lenses (spherical and toric) and corneal designed contact lenses for keratoconus.

Tools

We have tools to support contact lens fitting process.

Articles

Papers published by the Optometry Research Group of the IOBA Eye Institute of the University of Valladolid related with contact lenses.

Blog

A blog with posts about the Optometry Research Group of the IOBA Eye Institute of the University of Valladolid.

CALCULENS.com is the results of the doctoral thesis of Sara Ortiz Toquero, supervised by Dr. Raul Martin Herranz with the final aim to help contact lens and eye care practitioners. This doctoral thesis has been supported by the program: Estrategia Regional de Investigación Científica, Desarrollo Tecnológico e Innovación 2007-2013 co-funding from the Social European Fund of the Consejería de Educación - Junta de Castilla y León (Spain) and with the Convocatoria Lanzadera TC 2015 of the Fundación General de la Universidad de Valladolid (FGUVa). Finally, the contact lens company, CONOPTICA SL (Barcelona, Spain) has collaborated in this project as well.

our-team

Our Team

The Optometry Research Group of the IOBA Eye Institute of the University of Valladolid involves an experienced group of professionals, with national and international experience in Optometry and visual sciences research, teaching and clinic (eye exams and contact lens).

The development team of CALCULENS.COM have been:

Head of Optometry Research Group. PhD in Vision Science from the University of Valladolid (2010) and registered optometrist in Spain and the UK. He has over 20 years of clinical experience, teaching and research. He has collaborated with several national and international universities: Glasgow Caledonian University, Cardiff University, Plymouth University, between others.

Dr. Raúl Martín Herranz

Master in Research Vision Sciences (2012); Master in Optometry (2011) and Degree in Optometry from the University of Valladolid (2010). She is specialist in gas permeable contact lens fitting in keratoconus.

Sara Ortiz Toquero

Master in Optometry and Master in Research Vision Sciences (2008); Degree in Optometry from the University of Valladolid (1999). She is a contact lens expert with extensive experience in special fittings (irregular cornea, cosmetic, paediatric, etc.).

Guadalupe Rodríguez Zarzuelo

PhD in Vision Science from the University of Valladolid (2013); Master in Optometry and Master in Researc Vision Sciences (2008); Degree in Optometry from the University of Valladolid (2003). She is expert in contact lens and ocular surface, with extensive experience in calculating IOL, anterior segment surgery, etc.).

Dr. Victoria de Juan Herráez

calculator

Calculator

Contact lens fitting calculator

You can calculate the parameters of soft contact lenses; gas permeable lenses (spherical and toric) and corneal designed contact lenses for keratoconus; just typing the prescription and keratometry of your patient (these data could be completed with topographer data if you want).

If you register like user, you can save the parameters (base curve, power, diameter, etc.) of the contact lens that CALCULENS propose for your patient and moreover you can attach the parameters of the final fitted or prescribed lens. This will permit you a record of your fitted lenses and assess your professional evolution with the statistic tools of CALCULENS.

Go to Calculator
tools

Tools

Calculate the keratometry corneal radius of curvature in dioptres and millimetres.

Enter a value or move the bar to convert to millimeters or dioptres:

Corneal power

dioptres

Corneal radius

mm

Calculate the contact lens power with the spectacle prescription; designed for 12 millimetres vertex distance (use it in prescriptions higher of 4 dioptres).

Enter the values to calculate the distometry:

Power in glasses:

Sphere
Cylinder
Axis

Power lens:

Calculate the corneal astigmatism with corneal keratometry in millimetres or dioptres.

Enter the values to calculate the corneal astigmatism:

Keratometry:

K1
K1 Axis
K2
K2 Axis

Corneal astigmatism:

Calculate the refractive effect of the tear meniscus in gas permeable contact lenses fitting.

Enter the values to calculate the refractory effect:

Keratometry (in millimetres):

Kmin
Kmin Axis
Kmax
Kmax Axis
BOZR

Meniscus power:

Sphere
Cylinder
Axis

Calculate the induced astigmatism in gas permeable toric contact lenses fitting.

Insert both BOZR and the keratometry values to calculate the refractive effect of tear meniscus. If the induced astigmatism is greater than 1 D is recommended to fit a bitoric lens that compensate this induced astigmatism in anterior surface of the lens, verified by over-refraction.

Enter the values to calculate the induced astigmatism:

Keratometry (in millimetres):

Kmin
Kmin Axis
Kmax
Kmax Axis
BOZR1
BOZR2

Induced astigmatism:

Axis:

articles

Articles

Papers published by the Optometry Research Group of the IOBA Eye Institute of the University of Valladolid related with contact lenses.

Success of rigid gas permeable contact lens fitting.
Ortiz-Toquero S, Martin M, Rodriguez G, de Juan V, Martin R. Eye Contact Lens. 2016. In press

The influence of the refractive correction on the vision-related quality of life in keratoconus patients.
Ortiz-Toquero S, Perez S, Rodriguez G, de Juan V, Mayo-Iscar A, Martin R. Qual Life Res. 2016; 25: 1043-51.

Rigid gas permeable contact lens fitting using new software in keratoconic eyes.
Ortiz-Toquero S, Rodriguez G, de Juan V, Martin R. Optom Vis Sci. 2016; 93: 286-92.

Repeatability of placido-based corneal topography in keratoconus.
Ortiz-Toquero S, Rodriguez G, de Juan V, Martin R. Optom Vis Sci. 2014; 91: 1467-73.

Optical quality and intraocular scattering assessed with a double-pass system in eyes with contact lens induced corneal swelling.
de Juan V, Aldaba M, Martin R, Vilaseca M, Herreras JM, Pujol J. Cont Lens Anterior Eye. 2014; 37: 278-84.

Bitoric rigid gas permeable contact lens fitting for the management of a corneal scar caused by herpes zoster ophthalmicus.
de Juan V, Martín R, Rodríguez G. Clin Exp Optom. 2012; 95: 229-32.

Constancy of the Orbscan acoustic factor to detect contact lens-induced corneal swelling.
Martin R, Nuñez L, Sastre J, de Juan V, Rodriguez G. Clin Exp Optom. 2011; 94: 352-60.

Ocular tolerance of a new multipurpose solution specifically formulated for daily wear of silicone hydrogel contact lenses.
Martin R, Rodriguez G, de Juan V, Fernandez I, Sanchez I, de la Rosa C, de Paz I, Zalama M. Cont Lens Anterior Eye. 2011; 34: 17-21.

Differences in the daily symptoms associated with the silicone hydrogel contact lens wear.
Martin R, Sanchez I, de la Rosa C, de Juan V, Rodriguez G, de Paz I, Zalama M. Eye Contact Lens. 2010; 36: 49-53.

Contact lens-induced corneal peripheral swelling: Orbscan repeatability.
Martin R, de Juan V, Rodriguez G, Fonseca S, Martin S. Optom Vis Sci. 2009; 86: 340-9.

Corneal conjunctivalization management with high Dk RGP contact lenses.
Martin R. Cont Lens Anterior Eye. 2009; 32: 147-50.

Contact lens-induced corneal peripheral swelling differences with extended wear.
Martin R, de Juan V, Rodriguez G, Fonseca S, Martin S. Cornea. 2008; 27: 976-9.

Measurement of corneal swelling variations without removal of the contact lens during extended wear.
Martin R, de Juan V, Rodríguez G, Cuadrado R, Fernandez I. Invest Ophthalmol Vis Sci. 2007; 48: 3043-50.

Reverse geometry contact lens fitting in corneal scar caused by perforating corneal injuries.
Martin R, de Juan V. Cont Lens Anterior Eye. 2007; 30: 67-70.

Initial comfort of lotrafilcon A silicone hydrogel contact lenses versus etafilcon A contact lenses for extended wear.
Martin R, de Juan V, Rodriguez G, Martin S, Fonseca S. Cont Lens Anterior Eye. 2007; 30: 23-8.

Corneal conjunctivalisation in long-standing contact lens wearers.
Martin R. Clin Exp Optom. 2007; 90: 26-30.

Reverse geometry contact lens fitting after corneal refractive surgery.
Martin R, Rodriguez G. J Refract Surg. 2005; 21: 753-6.

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