Vision is rarely affected in patients with AH and SS, probably because the smooth surfaces of the AH bodies minimize light scattering and visual disturbances. Other types of vitreous opacities, however, such as aggregates of vitreous collagen within the vitreous body occurring after posterior vitreous detachment or in myopic vitreopathy, have irregular surfaces and induce considerable straylight and light scattering. In addition, the more anterior location of AH opacities in the vitreous body may preclude visual disturbances. Even if AH and SS do not cause visual impairment, they can sometimes interfere with the eye fundus examination, with the result that special imaging techniques such as fluorescein angiography and ultrasonography may be required to obtain a more precise evaluation.
To our knowledge, this is the first study to evaluate the performance of trifocal IOLs in eyes with AH or SS.
For patient satisfaction and spectacle independence, the results obtained for patients with unilateral AH or SS were similar in the postoperative survey performed 3 months after the surgical procedure to those of patients without these vitreous opacities and published previously by our group in a very large cohort study.1 After laser enhancement when needed, patients achieved 100% spectacle independence at all distances in this study group and in the previous population without AH and SS, namely, 99%, 98%, and 95% at distance, intermediate, and near vision, respectively, with the FineVision trifocal IOL. Satisfaction scores are also similar: 98.2% of patients were satisfied, and 98.2% would undergo surgery again in this group, whereas in the previous group (no AH and SS and implantation of a FineVision IOL), 98% were satisfied, and 97% would undergo surgery again.
Comparison of visual acuity results in the control and AH/SS groups revealed similar outcomes both before and after surgery. Preoperative visual acuity results confirm previously published findings, which show that vision is unaffected in most AH/SS cases. Equivalent postoperative results in both groups provide evidence that AH/SS vitreous opacities do not interfere with the visual performance of trifocal IOL. There was a statistically significant difference in CDVA between the groups, although it was not clinically significant (logMAR 0.03 vs 0.04).
Very few patients with AH and SS experience significant symptoms of visual disturbance or sequelae of vitrectomy surgery. No patients with these conditions were included in the study group. Although optimal results have been published after pars plana vitrectomy for various vitreoretinal conditions in patients who receive trifocal IOLs,12 caution should be exercised in patients with AH or SS and extremely dense vitreous opacities. Patients should receive careful counselling with realistic expectations before lens surgery and trifocal IOL implantation, with emphasis on the persistence of visual disturbances related to the vitreous opacities and the unlikely possibility that vitrectomy could be required in the future.
Besides, no interference in the eye fundus examination (which currently includes funduscopy and macular optical coherence tomography) was recorded in any of the patients in the AH/SS group before or after the lens surgery. Although AH and SS have not been associated with any other specific vitreoretinal disorder, a detailed macular evaluation is mandatory before implantation of a trifocal IOL. Thereafter, patients with AH or SS and dense vitreous opacities may require special care and ancillary tests to rule out macular or optic nerve disorders that may affect the performance of the diffractive trifocal IOL.
Regarding refractive results, no statistically significant differences were found in terms of predictability, efficacy, efficacy index, and percentage requiring laser enhancement. However, a clear trend towards better refractive outcomes was found in the control group. The difference was non-significant, probably because of the small sample size and the low incidence. These relatively poorer refractive outcomes could be due to the interference of the vitreous opacities in the optical interferometry system used (IOLMaster 500) to calculate axial length during ocular biometry. A falsely short axial length measurement with automated ultrasound biometry has previously been described in patients with AH.3,4 The finding was related to the interference of the increased vitreous opacities in the ultrasound measurements. However, to our knowledge, this type of artifact or interference has not been specifically described with the IOLMaster 500 partial coherence interferometry system.
The current study is subject to a series of limitations. It is retrospective, includes data from multiple surgical centers, and is based on 3 different trifocal IOL models. However, surgeons and optometrists from all the centers followed the same protocol for patient management. In addition, visual outcomes with both trifocal models are equivalent,1 and although a larger number of cases could have influenced the significance of certain results (see above), the number of cases seems sufficiently large to confirm the optimal clinical outcomes achieved, especially given the comparison with a control group.
In summary, this study, which is the first to assess the performance of diffractive trifocal IOLs in patients with unilateral slight and moderate AH and SS, confirms favorable outcomes for trifocal IOLs and supports implantation of this type of multifocal IOL in patients with this type of vitreous opacities.