Optimizing the intraocular lens formula constant according to intraocular lens diameter.

AIM: To determine whether the different diameters of a specific intraocular lens (IOL) have significantly different optimized SRK/T A constants and whether these new A constants can improve refractive outcomes. METHODS: Data were collected prospectively from Jan. 2011 to Dec. 2012 on all patients undergoing routine cataract surgery at a district general hospital in the UK. Patients were divided into three groups according to the size of the Akreos AO MI60 IOL used. A constants for the SRK/T formula were optimized according to the size of the IOL. These optimized A constants were then used to select future refractive outcomes. RESULTS: A total of 2398 cataract operations were performed during the study period of which 1131 met the inclusion criteria. The three optimized A constants for the different sized IOLs were 118.98, 119.13, 119.32. The difference between them was highly significant (P≤0.0001). Two optimized A constants for three sizes of IOL led to an improvement in refractive outcomes (from 93.4% to 94.6% of refractive outcomes within 1.00 D of predicted spherical equivalent). The optimized A constant for the largest IOL was based on a small number of cases and was not used. CONCLUSION: Optimizing the A constant for the three distinct sizes of the Bausch & Lomb Akreos MI60 lens lead to three significantly different A constants. In our practice, using two different optimized A constants for three different sized IOLs give the least refractive error, however, using three optimized A constants may give better results with a larger dataset.

Ophthalmic photographer virtual clinics in medical retina.

AIM: To determine whether ophthalmic photographers (OPs) can conduct virtual clinics (VCs) in medical retina appropriately and whether this increases clinic capacity. METHODS: Three OPs underwent a training programme to learn how to assess and manage macular edema secondary to diabetes or retinal vein occlusion. The 300 consecutive patients over a 7-month observation period in 2018 were assessed in VCs by both OPs and medical retina consultants. The degree of agreement in treatment decisions between doctors and photographers, as well as adverse events, was recorded. The change in number of patients seen in VCs over two years was also measured. RESULTS: There was 100% agreement in management decisions between doctors and photographers during the 300-patient observation period. No adverse events were recorded. In 2017, 572 patients were seen in VCs by doctors. After OP clinics were introduced in 2018, this number increased by 24% to 709 patients seen by both photographers and doctors. There was a significant increase in mean number of patients seen per month between 2017 (47.7±11.7) and 2018 (59.1±14.4; P=0.045, 95%CI -22.5 to -0.296). CONCLUSION: OPs can manage certain medical retina patients in VCs appropriately and can increase clinic capacity significantly for particular conditions.

Accuracy of intraocular lens calculations based on fellow-eye biometry for phacovitrectomy for macula-off rhegmatogenous retinal detachments.

OBJECTIVES: To determine the accuracy of using fellow-eye biometry for intraocular lens calculations for phacovitrectomy for macula off rhegmatogenous retinal detachments. METHODS: Retrospective case review of phacovitrectomies for consecutive macula off retinal detachments over 10 years. Optical and/or ultrasound biometry was performed for affected and fellow eyes. Prediction error was determined by calculating the difference between predicted and actual refractive outcomes. Results from fellow- and same-eye biometry were compared. RESULTS: Forty-two eyes were included. The mean prediction errors for fellow- and same-eye biometry were -0.01 ± 1.09 and -1.22 ± 2.32 dioptres, respectively, indicating a myopic shift for same eye biometry calculations. The mean absolute prediction errors for fellow and same eye biometry were 0.73 ± 0.80 and 1.57 ± 2.08 dioptres, respectively. The difference was statistically significant (P = 0.016). CONCLUSIONS: When appropriate, intraocular lens calculations using fellow-eye biometry for phacovitrectomy for macula off rhegmatogenous retinal detachments are accurate and better than those from same-eye biometry.

A Case Report of Conservative Management for a Roller-Coaster-Related Vitreous Haemorrhage.

The purpose of this report is to describe the case and management of an unexplained vitreous haemorrhage that occurred after repeated roller-coaster riding. The authors inadvertently demonstrate the value of observation over immediate surgery in certain situations and review the literature on vitreoretinal and other ocular complications after roller-coaster riding. A 26-year-old male presented 12 h after riding high-velocity roller-coasters with a left vitreous haemorrhage. A hazy view of the retina and B-scan revealed a bullous area of superior-temporal retinal lifting. A diagnosis of a presumed macula-on retinal detachment was made and the patient was listed for a pars plana vitrectomy retinal detachment repair. An abnormal clotting result, which was subsequently found out to be erroneous, ultimately delayed the procedure. During this delay the vision and retinal view improved to an extent whereby the diagnosis of a retinoschisis with an intraretinal cyst was made and surgery was avoided. The patient regained 6/6 vision, without the need to undergo surgery. Historically the management of an unexplained vitreous haemorrhage was observation with serial B-scans. The current evidence and practice for treating unexplained vitreous haemorrhage have since moved towards early surgical intervention. The authors highlight that despite the current trend, a place remains for conservative management for selected cases.