Statistics from Altmetric.com
A 10-year-old woman with open globe injury sequelae (repaired) and subsequent cataract development was operated for lens aspiration. The cataractous lens had a posterior capsular defect. So after lens aspiration, limited anterior vitrectomy was done and a three-piece intraocular lens (IOL, power 24 dioptre (D)) was placed in the sulcus and optic capture behind the capsule was attempted (figure 1A,B). The patient had an inferior fibrotic hammock of corneocapsular scar, which prevented inferior optic capture and thus postoperatively there was an IOL tilt (inferior optic was relatively anteriorly placed) (figure 1C,D). The resultant postoperative refraction had a 13 D astigmatism on retinoscopy (the corneal astigmatism on autorefractor-keratometer was only 2 D), indicating the majority astigmatism to be due to lenticular tilt. An IOL repositioning was done in which localised cutting of the inferior fibrotic hammock was done and the optic was captured behind the capsule completely (figure 1E,F). The astigmatism on retinoscopy reduced to 3 D. An I-Trace (ray tracing aberrometry) was done after the first surgery and then repeated after IOL repositioning (figure 2A,B). The Tracey refraction reduced from −12.62 D sphere+9.25 D cylinder at 106o to −2.12 D sphere −1.12 D cylinder at 162o (table 1—DS=dioptres sphere, DC=dioptres cylinder).
Tilted IOL has been well documented to manifest as astigmatism.1–3 The IOL tilt in our case was measured using an online protractor and the scan with the highest amount of tilt has been displayed and was found to be 14o anteriorly (figure 3). The tilt attributed to 8.13 D of lenticular astigmatism and 5.315 D of myopic shift (difference of spherical equivalents of pre and post-IOL repositioning Tracey refraction). The tilting in our case is different from previous documented cases in that in the earlier documented cases the nasal anterior tilt had an equal amount of temporal posterior tilt (tilt was around the central diameter axis), leaving the centre of mass position of the IOL unaltered.1–3 In contrast in our case, the superior optic was well in place, only the inferior optic was anteriorly dislocated (figure 3), resulting in anterior displacement of centre of mass of the lens by half the amount, the cause of the myopic shift.4 Traumatic cataracts (open globe injury sequelae) are unique locks each with their own unique keys to surgical approach. Corneoiridic scars, lens rupture and capsular fibrotic involvement make IOL implantation a challenge in these cases due to difficulty in finding a straight plane for IOL implantation. In traumatic cases, irregularity of pupil is another major issue, which makes visibility problematic and may cause visual illusions regarding centration of IOL. The IOL in our case seemed centred intraoperatively, as we could not ascertain any tilt. On first postoperative day, slit lamp examination showed tilting (elicited by oblique slit of light on the IOL). Retinoscopy also showed significant astigmatism re-enforcing our finding. Fluctuation of anterior chamber depth intraoperative or in the immediate postoperative period may cause the IOL to change its position (which might also have been a contributing factor in our case). So, a well-formed anterior chamber with fluid-tight incision is a must, incision to be sutured if necessary. A minor IOL tilt can cause significant ocular morbidity due to lower and higher order aberrations.3 I-trace is an objective method of documenting these aberrations and localising the cause of aberrations to cornea or the lens. In the above case, I-trace was not a diagnostic but a reinforcing tool for the findings. In the current era of premium IOLs, where sometimes the patients may not be happy despite an apparently well centred IOL, ray tracing aberrometry comes to a diagnostic rescue.
Optic capture pushes the IOL optic behind the world of tilted sulcus or lenticular bag planes making them a good option in these cases. To confirm an adequate capture, the membrane/capsule (behind which the optic is captured) can be nudged with a sinskey blunt hook or viscoelastic cannula just before hydrating the side incision and closing the surgery.
Intraocular lens (IOL) tilt causes lenticular astigmatism.
Traumatic cataracts and their outcomes are less predictable than usual cataracts because of variable involvement of cornea, iris, pupil, lens and variable fibrotic changes.
IOL capture is helpful in such cases as it bypasses the above planes for resting the optic.
Contributors SK—concept, surgery. AAB—surgery, preparation of manuscript. SN—capturing of data, retrieval of data. TS—retrieval of data.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.