Cataract surgery was revolutionized by the reevaluation of posterior chamber intraocular lenses.1 The J-loop haptic made it possible to implant an intraocular lens in the capsular bag and maintain low complication rates.2 Many haptic designs and intraocular lens materials were developed to guarantee good centration and minimal tilt.3 However, intraocular lens decentration induced by capsular bag contraction can still occur and ideal postoperative refraction (emmetropia, spherical equivalent −0.5 to +0.5 diopters and less than 1.0 diopter of astigmatism) may be achieved in only 55% of a non-selected population..4–6
The routinely used capsulorhexis is manually demanding and cannot guarantee the exact size of an anterior capsule opening.7 Image-guided femtosecond lasers can perform an anterior capsulotomy with reproducible size and circularity.8 In this case series, we used the anterior laser capsulotomy in combination with a new intraocular lens. The 90F intraocular lens (Morcher GmbH, Stuttgart, Germany) has the design of a C-loop intraocular lens with an additional flank (Figure 1). In contrast to the femtosecond laser-assisted in-the-bag lens technique, only the anterior capsule is fixated in the side flank, whereas the posterior capsule is kept intract and the intraocular lens is implanted in the capsular bag.9 Preoperative intraocular lens power calculations were performed using noncontact partial coherence laser interferometry (IOLMaster; Carl Zeiss Meditec, Jena, Germany). The Lens Opacities Classification System III was used for nuclear opalescence grading.10 To predict changes in intraocular lens position, the anterior chamber depth (cornea posterior to intraocular lens anterior) at 1 week and 1 month postoperatively was compared.
Scanning electron microscope images of the 90F intraocular lens (Morcher GmbH, Stuttgart, Germany). (A) Overview. (B) Flank between anterior and posterior haptic lips.
The patient was seated on the operating chair and the head was fixated. The nonapplanating patient interface was placed on the sclera and filled with balanced salt solution. With the patient lying under the laser system (Catalys Precision Laser System; Abbott Medical Optics, Inc., Santa Ana, CA), the docking process was completed. The integrated three-dimensional spectral-domain optical coherence tomography automatically visualized the anterior segment of the eye and calculated a treatment plan based on preprogrammed templates.
In all cases, the anterior capsulotomy was centered on the scanned capsule, which is found by fitting spheres to the anterior and posterior surfaces of the lens. A line is calculated by subtracting the center locations of the two spheres. The point where this line intersects the anterior lens surface is the scanned capsule. The capsulotomy diameter was set to 5.2 mm and the pulse energy was set to 4 μJ. An incision depth of 600 μm (with horizontal and vertical spot spacing of 5 and 10 μm, respectively) was selected. Grid spacing of the lens was adopted depending on the density of the lens nucleus. Normally, it is set between 200 and 500 μm with a central line repetition rate of one to three. The laser application started after treatment and safety zone confirmation. For the capsulotomy, the laser cut a cylinder that started in the lens and moved anteriorly (ie, forward) into the anterior chamber. Subsequently, the lens was fragmented.
After undocking, the patient was swiveled to the operating microscope. Two 1.2-mm paracenteses were manually made with a knife at the 10- and 2-o’clock positions. The 2.75-mm clear corneal cataract main incision was made at the 12-o’clock position. The central dimple-down maneuver confirmed a free capsulotomy. In this technique, the anterior chamber is filled with ophthalmic viscosurgical device and a blunt instrument is used to exert central pressure.11 After minimal hyrodissection, the lens can be aspirated without ultrasound energy in most cases. Bimanual irrigation/aspiration is used to remove the residual cortex. The diameter of the biconvex optic of the 90Fc intraocular lens was 5.5 mm. The total diameter was 11.5 mm and the A constant was 119.1. The 90F intraocular lens has four lips near the top of the optic. The haptics and two additional lips are at the bottom (Figures 1–2).
Intraoperative photograph of the 90F intraocular lens (Morcher GmbH, Stuttgart, Germany) (prior to loading it in the cartridge).
Under ophthalmic viscosurgical device protection, the 90F intraocular lens was implanted directly in the capsular bag using an injector system (Naviject; Medicel AG, Luchten, Switzerland). First, irrigation/aspiration was used to remove ophthalmic viscosurgical device behind the intraocular lens (two-compartment technique). Subsequently, the anterior capsule was placed in the lens at the 6-o’clock position and followed by placements at the 9-, 12-, and 3-o’clock positions (Figure 3). After ophthalmic viscosurgical device removal from the anterior chamber, acetylcholine chloride was injected and one drop of pilocarpine (Pilomann 2%; Bausch & Lomb, Rochester, NY) was instilled after hydration of the incision to obtain miosis. After surgery, ofloxacin and dexamethasone ophthalmic ointment were applied. Finally, the eye was covered with a patch. There was a 1-month follow-up period including determination of corrected distance visual acuity, measurement of the anterior chamber depth (Visante OCT; Carl Zeiss Meditec), and slit-lamp biomicroscopy (retinal fundus examination after topical medical mydriasis).
Slit-lamp photograph at 1 month postoperatively.
In this feasibility consecutive prospective case series, 6 eyes of 6 patients underwent femtosecond laser-assisted capsulotomy and 90F intraocular lens implantation in the capsular bag. The mean patient age was 74 ± 9 years (range: 57 to 84 years) and mean cataract nucleus density was grade 3.17 ± 0.75 (Lens Opacities Classification System III; range: 2 to 4). In all cases, the preoperative pupil size was larger than 7 mm. No complications occurred. The anterior capsulotomy was free in all cases and no tags or adhesions were observed. Furthermore, it was possible to position the anterior capsule in the 90F intraocular lens optic in all cases. All patients achieved a significant increase in visual acuity. The preoperative mean corrected distance visual acuity (logMAR) was 0.37 ± 0.14 (range: 0.6 to 0.2). At 1 week postoperatively, the mean corrected distance visual acuity increased to 0.1 ± 0.21 (range: 0.4 to −0.2; P = .003). At 1 month postoperatively, the mean corrected distance visual acuity was 0.07 ± 0.16 (range: 0.2 to −0.2; P = .363) (Figure 4). The spherical equivalent was not statistically different between 1 week (−0.56 ± 0.53 diopters) and 1 month (−0.66 ± 0.54 diopters) postoperatively (P = .10). In this time period, the average individual anterior chamber depth differed by 0.01 ± 0.05 mm (range: −0.06 to 0.04 mm; P = .70). At the 1-month follow-up, no complications (eg, increased inflammation, fibrin reaction, tilt, optic or haptic degradation, pigment dispersion, iris capture, or macular edema) were observed. All capsulotomy edges remained within the intraocular lens optic rim. No patients reported glare sensitivity or light sensations.
Corrected distance visual acuity before surgery and 1 week and 1 month after surgery (n = 6).
Cataract surgery is now similar to a refractive procedure with high demands on the refractive outcome.12 Having a good and intraoperatively fixed position and centration is essential for toric, multifocal, and aspherical intraocular lenses.3,13
Femtosecond lasers made it technically possible to cut an anterior capsulotomy with preset size, circularity, and sufficient strength.8,14 The 90F intraocular lens used in this study has a 360° groove in which the anterior capsule is placed, whereas the intraocular lens haptics are positioned in the capsular bag (Figure 5). The first 90F intraocular lens design did not have a sharp posterior edge to prevent posterior capsule opacification. A newer design with a sharp posterior edge, thinner wings, and different design specifications is under clinical evaluation. Centering the anterior capsulotomy on the scanned capsule provides more potential advantages than centering the capsulotomy on the pupil. This is also true for asymmetrically dilating or decentered pupils and decentered docking. No complications were observed in our patients. However, all patients had a pupil size greater than 7 mm. The implantation may be more difficult and demanding with a smaller pupil. The anterior chamber depth minimally differed and was not statistically significant at 1 week and 1 month postoperatively. It can be assumed that the effective lens position changed slightly, if at all. An earlier and more predictable refractive outcome, stable sufficient intraocular lens centration, and less intraocular lens rotation seem possible with the 90F intraocular lens and laser technology. However, prospective clinical trials with a larger number of patients are necessary to confirm these early findings and to investigate long-term results, including deviation from predicted effective lens position, deviation from target refraction, and intraocular lens rotation.
Anterior segment, three-dimensional spectral-domain optical coherence tomography immediately after surgery.
- Pearce JL. New lightweight sutured posterior chamber lens implant. Trans Ophthalmol Soc U K. 1976;96:6–10.
- Shearing SP. Mechanism of fixation of the Shearing posterior chamber intra-ocular lens. Intraocul Lens Med J. 1979;5:74–77.
- Crnej A, Hirnschall N, Nishi Y, et al. Impact of intraocular lens haptic design and orientation on decentration and tilt. J Cataract Refract Surg. 2011;37:1768–1774. doi:10.1016/j.jcrs.2011.04.028 [CrossRef]
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- Chylack LT Jr, Wolfe JK, Singer DM, et al. The lens opacities classification system III. The Longitudinal Study of Cataract Study Group. Arch Ophthalmol. 1993;111:831–836. doi:10.1001/archopht.1993.01090060119035 [CrossRef]
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