Case studies

Advanced dispensing principles

This case record was submitted by Pragna Raghwani.

At Specsavers Barnet, we recently managed a complex spectacle prescription combining high myopia, significant astigmatism, and both horizontal and vertical prism correction. The case was dispensed by trainee dispensing optician Priya under the supervision of Pragna, providing an excellent opportunity to apply advanced dispensing principles in practice.

Prescription

Right: −5.00 / −4.25 × 105 VA 6/9−2
Left: −5.25 / −2.50 × 75 VA 6/7.5−2

Prism (distance): 6Δ Base Out OU with 2.5Δ Base up
Prism (near): 4.50 Δ Base Out OU with 2.5Δ Base down

The combination of high cylindrical power and significant prism placed the lenses within a special-order category, requiring careful planning and precise measurements. To manage lens thickness and optimise optical performance, Priya selected a compact, well-centred frame. High-index lenses were specified, and accurate monocular PD measurements and frame alignment were essential to ensure appropriate prism delivery.

Given the complex binocular requirements, the finished spectacles needed to provide the prescribed prism correction without introducing additional unwanted prismatic effects through lens decentration.

The outcome was highly successful. The patient reported clear, stable vision and excellent comfort with the spectacles. Their satisfaction with the result was reflected in their return to order a second pair.

This case highlights how skilled dispensing, careful measurement and effective clinical collaboration can transform even complex prescriptions into successful visual outcomes.

The team at Specsavers Barnet is proud to contribute to the profession and to celebrate the work of dispensing opticians as part of the Association of British Dispensing Opticians centenary celebrations.