NEGATIVE DYSPHOTOPSIA
Negative dysphotopsia (ND) is an enigmatic condition with no clearly established mechanism. US researchers conducted a retrospective study asking how best to manage ND linked with cataract surgery. They compared various strategies in second eye surgery in patients who had reported IOL exchange, reducing posterior chamber depth, piggyback secondary IOL placement, bag-to-sulcus IOL exchange and reverse optic capture. ND was associated with acrylic or silicone IOLs of square- or round-edge design. It was reduced, eliminated or prevented when the IOL optic overlaid the anterior capsulotomy rather than when the capsule edge overlaid the optic. Bag-to-sulcus IOL exchange and reverse optic capture were highly successful in managing or preventing ND.
S Masket et al., JCRS, “Surgical management of negative dysphotopsia”, Volume 44, Issue 1, 6–16.
OPTIMISING IOL POWER CALCULATION
The Wang-Koch method for optimisation of IOL formulas was developed to reduce hyperopic surprises in eyes with long axial lengths (AL). The current study attempts to provide external validation for this approach. The study looked at 262 eyes with an AL of 25.0mm or longer and compared the predicted postoperative spherical equivalents as calculated from the Holladay 1 formula with the three-week postoperative spherical equivalents. The secondary outcomes of mean absolute error and median absolute error were also analysed. The refractive targets were achieved more often with use of the Wang-Koch adjustment in eyes with ALs longer than 27.0mm, but not in eyes with ALs between 25.0mm and 27.0mm.
M Popovic et al., JCRS, “Wang-Koch formula for optimization of intraocular lens power calculation: Evaluation at a Canadian centre”, Volume 44, Issue 1, 17–22.
PAEDIATRIC TRAUMATIC CATARACT
Between 12% and 46% of all paediatric cataracts are attributable to ocular injury. Cataract surgery with IOL placement, when possible, is considered the safest and best practice in cases of traumatic cataract. However, because of the risk for amblyopia and the ongoing growth of the eye, refractive rehabilitation following surgery is clinically challenging. The current study evaluated 106 children, mean age 7.6 years, looking at refractive and visual outcomes of paediatric traumatic cataract requiring surgery and evaluating the factors influencing success. Seventy-nine children had open-globe injuries and 27 had closed-globe injuries. The study concluded that surgical intervention for traumatic cataract had generally good visual and refractive outcomes. Intraocular lens management as a secondary or staged procedure had low complication rates and can lead to higher accuracy of the target refraction. Closed-globe injuries and older age were associated with better visual outcomes and refractive accuracy.
A Yardley et al., JCRS, “Refractive and visual outcomes after surgery for Pediatric traumatic cataract”, Volume 44, Issue 1, 85–90.
