I have been updating some calculators, here are the links:

  • Prisms: calculate the magnitude and angle resultant of two prisms, useful to know the orientation and magnitude of a fresnel prism in glasses. 

prisms

 


  •  Optotypes: Calibrate your optotypes or see what is the visual acuity if you change the intended distance of the test.

optotypes


sia calculator


  • Glaucoma guide: Based on the flow charts of the European Glaucoma Society 2nd edition.

glaucoma guide

 


  • And of course RSG, much more than a calculator, the best tool to monitor your refractive surgery outcomes.

RSGintro

 


In the clinical study The Royal College of Ophthalmologists’ National Ophthalmology Database study of cataract surgery: report 1, visual outcomes and complications the aim is to describe the outcomes of cataract surgery in the United Kingdom. The data is of 118 114 eyes from 127 685 patients that underwent cataract surgery between 2006 and 2010. 

The first table shows the ocular co-pathologies in the operated eye by grade of the operating surgeon, as the number of co-pathologies and by co-pathology. About the number of co-pathologies in the operated eye I made the following graphic:

catComplications1

 

We can easily see that consultant surgeons have more eyes with co-pathologies than the independent non-consultants and the trainees. The Y axis distance is not linear as you may have noticed, it's the cubic root of the value. The following graphic shows the recorded co-pathologies:

catComplications2

 

This could be a good indication of what co-pathologies we can expect in cataract surgery in the UK. The second table shows the intraoperative complications in the operated eye by grade of the operating surgeon, here is the graphic, you can click on it to see a larger version:

catComplications3

 

We can see that the most common complication is the posterior capsule rupture and/or vitreous loss. Because of the number of operated eyes this is a nice benchmark for a surgeon to see how you are doing in your practice.


The EUREQUO database (I quote from their website) provides a means to audit surgical results and encourages surgeons to make adjustments to their techniques and improve their outcomes. One important use of the database is benchmarking. EUREQUO is funded by ESCRS. The study The European registry of quality outcomes for cataract and refractive surgery (EUREQUO): a database study of trends in volumes, surgical techniques and outcomes of refractive surgery is based on it and there are several tables. I will make two graphics from the first two tables.

The first one is Number of refractive procedures (eyes), reported into the database, between February 4th 2004 and June 30th 2014umber of refractive procedures (eyes), reported into the database, between February 4th 2004 and June 30th 2014. Well to put the percentages by procedure in a graphic is really straight forward:

 

eurequo1

 

The number of eyes is different from the one reported in the study of 27339 but 26598 is the number of procedures I get by adding all the number of procedures from the table.

The second table is Type of (primary) procedure, indication, mean age and range of preoperative refraction. This one is more interesting since it gives procedure, indication, mean age at surgery, maximum and mean refraction preop by indication and number of eyes. Now, leaving aside mean age at surgery I will show you all the other data in a single graphic:

 

eurequo2

 

Each bar shows the range, the bar width is proportional to the number of eyes, and the vertical lines are the mean refraction for that bar, that means that for PRK for myopes the mean is -3.2 D and for the hyperopes +1.5 and you can see very easy that there are many more myopes than hyperopes for PRK (3693 myopes and 308 hyperopes from the table). We can also see that although for lasik and hyperopes the range is larger than for RLE, the mean is smaller.