Management of post-cataract surgery triad: Microcornea, Soemmerring’s ring and aphakia

Issue: May 10, 2024

ByAmar Agarwal, MS, FRCS, FRCOphth

ByDhivya Ashok Kumar, MD, FRCS, FICO, FAICO

BySoosan Jacob, MS, FRCS, DNB

Fact checked byChristine Klimanskis, ELS

Microcornea often presents with a cataract, sometimes in childhood because of syndromic associations and sometimes in adulthood with increasing nuclear sclerosis.

Often, this is a hard brown cataract because of reluctance on the part of both the patient and the surgeon to operate on a high-risk eye. Cataract surgery is difficult in such eyes. Small eye phenotypes such as microphthalmos, nanophthalmos, posterior microphthalmos and cornea plana have their prognosis and management influenced by coexisting ocular anomalies.

Figure 1. Illustration image showing the difference in a normal cornea (a and b) and microcornea (c and d) with a microchamber and a microbag.

*Source: Amar Agarwal, MS, FRCS, FRCOphth, Dhivya Ashok Kumar, MD, FRCS, FICO, FAICO, and Soosan Jacob, MS, FRCS, DNB*

Challenges in microcornea

Microcornea is associated with a microchamber and a microbag (Figure 1). Phacoemulsification can cause damage to all structures. Despite requiring a large incision relative to the corneal size, it is therefore often better to do an extracapsular cataract extraction (ECCE) to avoid damage to the posterior capsule, iris and endothelium. However, even with an intact posterior capsule, it is difficult to seat an IOL within the smaller than normal capsular bag. The optic fills up the bag, and the haptics fold over, unable to open fully (Figure 2). The IOL power required is generally high, and microcornea causes overcrowding of the capsular bag and the angle, increasing the risk for IOL tilt, uveitis and glaucoma postoperatively. Thus, these patients are often left aphakic after lens aspiration or ECCE. Many times, there is also a breach in the posterior capsule, sometimes following planned posterior capsulectomy and anterior vitrectomy in a child or sometimes due to a posterior capsular rent after difficult surgery.

Figure 2. Illustration image showing the optic filling up the bag and the haptics unable to unfold fully.

Emergence of clinical triad

In microcornea eyes, cortical removal is often incomplete, leading to a Soemmerring’s ring, a type of post-surgery capsular opacification, developing in the peripheral capsular fornix. This results in a triad of problems: microcornea, posterior capsular rent with aphakia and Soemmerring’s ring. What does this lead to, and why is it a special situation? These patients who otherwise need extra high plus spectacles would benefit greatly from an IOL. But the Soemmerring’s ring can complicate surgery and its results. Surgery can be difficult, and it can cause an IOL to tilt, thus distorting already poor optics even more. The cataract can drop into the vitreous during surgery, and the Soemmerring’s ring can dislodge and drop into the vitreous through the posterior capsular defect, causing vitritis and consequent problems. In addition, in the monocameral eye, it can also migrate to the anterior chamber and cause corneal endothelial decompensation.

Management of triad

We prefer performing a glued IOL scaffold in this situation. A trocar anterior chamber maintainer is inserted, and flaps are created for the glued IOL (Figure 3). Sclerotomies are made such that they enter under the Soemmerring’s ring. A glued IOL scaffold is then performed in such a way that the optic lies under the Soemmerring’s ring. Iris hooks can be used to improve visualization (Figure 4). The IOL haptics are trimmed and tucked into place (Figure 5). The Soemmerring’s ring is then removed, with the IOL optic acting as a scaffold and helping prevent vitreous drop. The flaps and conjunctiva are finally sealed with glue. This technique deepens the chamber, prevents angle crowding and angle-closure glaucoma, and gives a well-centered, stable IOL without tilt. There are no loose fragments of the Soemmerring’s ring, which can dislocate in the future.

Figure 3. Illustration images showing the position of the scleral flaps and introduction of the infusion cannula, followed by glued IOL scaffold method under the Soemmerring’s ring and haptic externalized under the flap.

Figure 4. Illustration images showing the intraoperative pupil dilatation using iris hooks followed by gentle retrieval of Soemmerring’s ring pieces from under the iris and positioning of Soemmerring’s ring material above the surface of the IOL optic in which the IOL acts as scaffold to prevent drop into vitreous.

The surgical results are thus gratifying both anatomically and visually, and the eye remains quiet postoperatively. This can also be achieved using the Yamane technique. The Soemmerring’s ring is fragile. The fragments may be cut and aspirated by the vitrector, preferably a 23-gauge vitrector. Or they may simply be brought out through the main port. Attempting to hold the Soemmerring’s ring fragments with forceps can result in crushing and breakage into multiple fragments, which are then more difficult to bring out. The haptics can be trimmed before tucking so that an unusually large amount of tuck can be avoided. Anterior vitrectomy is done to remove any vitreous strands and prevent vitreous traction while externalizing the haptics. Intravitreal triamcinolone acetonide staining helps visualize vitreous tags well.

Figure 5. Illustration images showing the process of emulsification of Soemmerring’s material on the IOL optic and the completion of removal of the Soemmerring’s material and haptic trimmed and tucked in the sclera.

Advantages of glued IOL scaffold technique

There are advantages with the glued IOL scaffold technique in these eyes. First, there is no risk for IOL tilt anymore. Second, there is no longer crowding of the IOL within the eye. The haptics are brought out, and the optic sits comfortably within the eye. The glued IOL allows the iris to fall back and prevents angle crowding. The intrascleral Scharioth tuck helps stable placement of the IOL. Third, there is no risk for postoperative dislodgement of the Soemmerring’s ring fragments. Last, the glued IOL scaffold technique helps prevent intraoperative drop of fragments.

Alternative options

The other options for such patients include:

Sulcus placement after haptic trimming: In this technique, exact sizing in the form of unequal shortening or overshortening can result in IOL decentration or even a mobile IOL.
Customized IOLs with smaller optics and smaller overall diameter: Single-piece acrylic IOLs cannot be implanted in the sulcus, and three-piece customized IOLs have to be ordered. However, customization can be expensive and may not be universally available.
Supracapsular glued IOL: In case of complete 360° Soemmerring’s ring, a supracapsular glued IOL technique may be done so that the optic sits over the anterior capsule, and the haptics are brought out for intrascleral haptic fixation. Surgical manipulation needs to be gentle without disturbing the Soemmerring’s ring. But all the above options work well only with 360° Soemmerring’s ring within an intact anterior capsule so that the anterior surface is flat to allow fixation of the IOL without tilt. In eyes with a broken anterior capsule at the time of original surgery, the proliferation may not have a uniform anterior surface, and this can result in IOL tilt if left behind.

Conclusion

The above technique for the rare triad of microcornea, posterior capsular rent with aphakia and Soemmerring’s ring allows removal of the proliferative material with a scaffold in place to prevent a drop of fragments. It allows stable IOL fixation without tilt or decentration. It also allows the optic to sit uncrowded within the posterior chamber without compressing the angle or rubbing on the posterior surface of the iris. This decreases the risk for complications such as uveitis, glaucoma and cystoid macular edema. Thus, we believe that this triad can be managed well with a glued IOL scaffold technique, resulting in a stable, well-positioned IOL.

References:
Agarwal A, et al. J Cataract Refract Surg. 2008;doi:10.1016/j.jcrs.2008.04.040.
Agarwal A, et al. J Cataract Refract Surg. 2013;doi:10.1016/j.jcrs.2013.01.019.
Gimbel HV, et al. J Cataract Refract Surg. 2008;doi:10.1016/j.jcrs.2008.03.046.
Grewal DS, et al. J Cataract Refract Surg. 2012;doi:10.1016/j.jcrs.2012.02.023.
Hazin R, et al. Middle East Afr J Ophthalmol. 2008;doi:10.4103/0974-9233.51999.
Jacob S, et al. J Cataract Refract Surg. 2017;doi:10.1016/j.jcrs.2017.02.006.
Narang P, et al. J Cataract Refract Surg. 2015;doi:10.1016/j.jcrs.2015.02.020.
Tooke FT. Trans Am Ophthalmol Soc. 1933;31:68-76.

For more information:
Amar Agarwal, MS, FRCS, FRCOphth, director of Dr. Agarwal’s Eye Hospital and Eye Research Centre, is the author of several books published by SLACK Books, sister company of Healio publisher Ocular Surgery News, including Phaco Nightmares: Conquering Cataract Catastrophes, Bimanual Phaco: Mastering the Phakonit/MICS Technique, Dry Eye: A Practical Guide to Ocular Surface Disorders and Stem Cell Surgery and Presbyopia: A Surgical Textbook. He can be reached at aehl19c@gmail.com; website: www.dragarwal.com.

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Disclosures: The authors report no relevant financial disclosures.

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