# Lens Calc - Optical Dispensing

> Optical dispensing calculations for eye care professionals. (iPhone/iPad app by Optical Directions Consulting.)

- Source: https://appshunter.io/ios/app/lens-calc-optical-dispensing/id359616750 (this page in markdown: same URL + `.md`)
- Developer: [Optical Directions Consulting](https://appshunter.io/developer/309309098)
- Category: Medical, Utilities
- Price: $1.99
- Rating: 5.00/5 from 1 App Store ratings · 2 written reviews indexed
- Age rating: 4+
- Requires: iOS 12.0 · 8 MB
- Languages: American English
- Released: 2010-03-06
- Data updated: 2026-08-31
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/lens-calc-optical-dispensing/id359616750/reviews.md

## What is Lens Calc?

LensCalc: The six most important calculations for all optical retail assistants, optical dispensers or dispensing optician. Oh, and optometrists might benefit too. LensCalc includes Vertex Distance, Effective Diameter, Lensmeter Helper, Transposition, Lens Thickness Estimation and Induced Prism, in a quick & easy to use format. It also includes a progressive lens markup helper!

Vertex Distance: Enter the lens power & two vertex distances. LensCalc will give you the new power required, and tell you if the difference is significant.

Effective Diameter: Enter the Frame PD, Widest Diameter & Patient's PD. LensCalc tells you the required blank lens diameter.

Vertometer / Lensmeter Helper: Enter the two powers and the axis of the second power. LensCalc gives you the proper minus cyl form. Because sometimes those plusses and minuses are just a bit too confusing!

Transposition: Enter the lens power in plus cyl form, and LensCalc will give you the minus cyl form. Useful when you've got to deal with those dinosaur Rxs. Or, if you are a dinosaur, convert those new-fangled minus cyl prescriptions into that old favourite, plus cyls.

Induced Prism: Enter the power, decentration and direction of decentration. LensCalc tells you how much prism and the base direction. It'll also tell you the effective power of the lens in that direction, to aid with dispensing advice.

Lens Thickness: Enter power, centre/edge thickness, lens diameter and refractive index. LensCalc tells you the resulting edge or centre thickness.

So, they're all there: the six most common calculations, and designed for speed and ease of use. What an excellent idea.

Multifocal markup: Place your marked-up lens on the iPhone screen, drag the top, bottom & centre markers to the appropriate place and LensCalc tells you the optical centre height, the frame depth and the datum measurement. Use it when fitting or when checking jobs!

## Key features

- Vertex Distance calculation
- Effective Diameter calculation
- Lensmeter Helper
- Transposition tool
- Lens Thickness Estimation
- Induced Prism calculation
- Progressive lens markup helper

## Recent user reviews (2 of 2)

All indexed reviews: https://appshunter.io/ios/app/lens-calc-optical-dispensing/id359616750/reviews.md

### 3/5 — Good

*2012-05-14*

Useful easy to use found simple and good as a back up guide

### 5/5 — Awesome app

*2011-01-26*

Very very helpful app. The lens thickness calculator is very accurate and particularly helpful. Well worth the money!

## Frequently asked questions about Lens Calc

### What are the main optical calculations Lens Calc offers?

Lens Calc offers six key calculations: Vertex Distance, Effective Diameter, Lensmeter Helper, Transposition, Lens Thickness Estimation, and Induced Prism. It also includes a progressive lens markup helper.

### Is Lens Calc suitable for optometrists?

Yes, the app is designed for optical retail assistants and dispensing opticians, but optometrists may also find its calculations beneficial for their practice.

### How does Lens Calc help with lens transposition?

The Transposition feature allows you to enter a lens power in plus cylinder form and receive the minus cylinder form, and vice versa. This is useful for dealing with various prescription formats.

### Can Lens Calc assist with lens thickness?

Yes, by entering the lens power, center/edge thickness, lens diameter, and refractive index, Lens Calc will calculate the resulting edge or center thickness.

### What is the price of Lens Calc?

Lens Calc is a paid application, priced at $1.99.

### On which devices can I use Lens Calc?

Lens Calc is supported on iPhone and iPod devices.

### How often is Lens Calc updated?

The latest version, 2.5, was released on July 27, 2025, indicating recent updates and ongoing support for the application.

### Does Lens Calc have ads?

No, Lens Calc does not contain advertisements, providing an uninterrupted user experience.

## Version history (last 5 releases)

### 2.5 — 2025-07-27

Bug fix for effective diameter screen.

### 2.4 — 2025-07-24

Updated to work with modern devices.
Fixed bug with Vertex Distance screen.

### 2.3 — 2022-06-04

Version 2.3:
Oh dear. Version 2.1 had more bugs in it than an entomologist's office. Sorry about that.
This version fixes the inability to even use the Effective Diameter tab.

For 2.2:
Fixed bugs on the Vertex Distance page which kept flipping around the vertex of Rx and specs values. Also fixed the precision value not being remembered.
Also the plus cyl form switch on the power entry screen was messing up the cyl power.

For 2.1:
Fixed bugs on lens thickness page which always showed "edge thickness" even for a minus lens, and only allowed 1 decimal point for the refractive index.
Also updated to work well with iOS 15.

If you want new features or calculations, don't hesitate to contact me!

### 2.2 — 2022-05-29

For 2.2:
Fixed bugs on the Vertex Distance page which kept flipping around the vertex of Rx and specs values. Also fixed the precision value not being remembered.
Also the plus cyl form switch on the power entry screen was messing up the cyl power.

For 2.1:
Fixed bugs on lens thickness page which always showed "edge thickness" even for a minus lens, and only allowed 1 decimal point for the refractive index.
Also updated to work well with iOS 15.

If you want new features or calculations, don't hesitate to contact me!

### 2.1 — 2022-05-26

Fixed bugs on lens thickness page which always showed "edge thickness" even for a minus lens, and only allowed 1 decimal point for the refractive index.

Also updated to work well with iOS 15.

If you want new features, don't hesitate to contact me!

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## More apps by Optical Directions Consulting

- [Opticalc Contact Lens Calc](https://appshunter.io/ios/app/opticalc-contact-lens-calc/id309309095)
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All apps by Optical Directions Consulting: https://appshunter.io/developer/309309098

## Related topics

[dispensing](https://appshunter.io/ios/topics/dispensing) · [optical](https://appshunter.io/ios/topics/optical)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-31.*