Sir,

Lamellar cataract usually develops after the establishment of fixation, involves the lamellae surrounding the fetal nucleus peripheral to the Y sutures, and is usually progressive and bilateral.1 Herein, we describe challenges in intraoperative imaging and the software modifications required for successful femtosecond laser cataract surgery (FLACS) in such cataracts.

Case report

A 26-year-old male presented with bilateral lamellar cataracts visualized on slitlamp examination and Scheimpflug Imaging (Figure 1). His best-corrected visual acuity was 20/60 OD and 20/40 OS. He elected to undergo bilateral FLACS followed by implantation of a multifocal intraocular lens (IOL).

Figure 1
figure 1

Preoperative Scheimpflug image (a) and intraopertive anterior-segment optical coherence tomography (AS-OCT) (b) demonstrating the lamellar cataract.

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During femtosecond laser treatment (Catalys Precision Laser System, Optimedica, Sunnyvale, CA, USA), in-built spectral-domain anterior-segment optical coherence tomography imaging software incorrectly detected the posterior margins of the lamellar portion of the cataract and the posterior lens margin. Lens surface fitting error messages were noted precluding further treatment (Figure 2a). Adjustments were made with the software calipers to manually delineate the correct posterior boundary of the lens with adequate safety zones (Figure 2b). Both eyes had similar lens morphology and densitometry on Scheimpflug images and a similar error was encountered in the other eye as well. The laser energy settings were maximized with three passes and set at five micro-joules. Lens fragmentation was performed using the quadrant grid pattern with a 350-μm grid size.

Figure 2
figure 2

(a) Segmentation error (inset) using intraoperative AS-OCT that incorrectly identified the posterior boundary of the lamellar portion of the cataract as the posterior lens margin. (b) Manual segmentation (inset) permitted accurate delineation of anatomical landmarks including the posterior lens margin with an adequate safety zone, which allowed the femtosecond laser to proceed with clear corneal incisions, limbal relaxing incisions, anterior capsulotomy, and lens fragmentation.

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Following the femtosecond procedure, the capsulotomy was found to be free floating and nuclear removal was completed using the irrigation–aspiration probe only. A single-piece multifocal IOL ZMBOO with a +4D add was placed in the capsular bag. At the 2-week follow-up his best-corrected vision was 20/20 OU and J1 OU.

Comment

FLACS has been used for pediatric cataracts.2, 3 Primary multifocal IOL implantation has been shown to be effective for teenage-onset bilateral cataracts.4, 5 This report highlights intraoperative modifications required in cases of lamellar cataracts to accurately identify the lens anatomic boundaries permitting successful FLACS. It is possible that this issue can be encountered with other types of congenital and acquired cataracts as well and warrants careful confirmation of the anatomical boundaries and readjustment as required. It is important for surgeons using FLACS to be aware of how laser and software settings may need to be modified intraoperatively.