How to approach a complex cataract case
When teaching my ophthalmology residents, I find that going through an entire case from initial consultation to postoperative care is a great way for them to learn how to approach a complex cataract case. This method requires them to put together a wide range of skills including detecting subtleties on the slit lamp microscope exam, determining lens power calculations, handling intraoperative challenges and managing the postoperative course.
The patient in this case is a relatively young man of 45 years who has a lifelong history of high myopia, retinal detachments and poor vision. He had bilateral scleral buckles performed in another country decades ago with a good result in the right eye but with the development of phthisis bulbi in the left eye. He is therefore monocular and relies on his right eye for all of his daily tasks, which include computer work during the day and playing in a music group in the evenings. He used larger fonts on his computer previously but now notices that in the past year or so this is insufficient, and he is unable to function because his best corrected vision is now 20/200.
He was seen by his retina specialist who noted that his vision was previously 20/50, and his retina was noted to be attached with a good result from the scleral buckle. In his most recent visit, the retina specialist noted a small superior break and peripheral detachment, which was treated with a pneumatic retinopexy. He is now being sent for cataract surgery in order to restore his vision and improve the view of the posterior segment.
The patient has a best corrected vision of 20/200 in the right eye and no light perception in the left eye. Slit lamp examination shows a fairly normal anterior segment in the right eye and phthisis bulbi in the left eye. The maximum pupil dilation is 4.5 mm in the right eye, and the cataract appears to be primarily nuclear sclerotic with a small anterior polar opacity (Figure 1). The anterior chamber is somewhat shallow, which is surprising in this highly myopic eye. There is a small degree of phacodonesis noted. The eye is unable to be measured using optical coherence biometry, but ultrasound A-scan shows an axial length of 30 mm.
Retroillumination in this patient is very important because it alerts us to two important findings: The patient has a posterior polar cataract, and there are radial wrinkles on the posterior capsule (Figure 2). This posterior polar cataract explains why the optical methods of measuring axial length were unsuccessful, and it also means that the complication rate will potentially be much higher. Studies by Robert Osher, MD, and Abhay Vasavada, MD, demonstrated that approximately one out of three patients with posterior polar cataract will have a posterior capsule defect or rupture at the time of cataract surgery. The striae in the posterior capsule indicate that the posterior capsule is likely already violated at the site of the polar opacity, and this can account for why the patient noted a recent decline in vision. As the posterior capsule defect developed, the polar cataract worsened, and the normal zonular forces induced the radial wrinkles.
This patient is young and monocular and has had multiple retinal detachments. Any complication that threatens his sight could be catastrophic for him and could severely restrict his life. What are the possible approaches to his case?
We could attempt cataract surgery alone with care taken to minimize the risks using specialized techniques for posterior polar cases, such as doing viscodissection. With a pre-existing defect in the posterior capsule, even careful viscodissection could result in a wide-open defect and dislocation of the nucleus into the vitreous cavity. This would mean a second surgery by the retina specialist to retrieve the dropped nucleus. In addition, if there is vitreous prolapse at the time of cataract surgery, the risk of retinal detachment is very high, and an anterior vitrectomy may be more traumatic than a posterior approach.
Perhaps a better approach would be to do the surgery in combination with the retina specialist so that as soon as the nucleus drops, it can be removed with a pars plana lensectomy and vitrectomy. Alternatively, the vitreoretinal surgeon can do the pars plana vitrectomy and lensectomy solo, removing the cataract from the posterior approach, and then leaving the eye aphakic. With the long axial length, the ideal IOL power for sulcus fixation was calculated to be +4 D for a postop goal of plano. At a second date, an IOL could be placed in the eye, or perhaps the eye can be permanently left aphakic because the approximate refraction would be +2.5 D spherical equivalent, which is an easy spectacle prescription to tolerate.
Surgical course and postoperative recovery
We opted for the teamwork approach with both the cataract surgeon and vitreoretinal surgeon present in the operating room for the case. The corneal incision was made, and a round capsulorrhexis was achieved even though the zonular support was noted to be weak. Very careful viscodissection was performed with a dispersive viscoelastic, and the chopper was used to bring the nucleus out of the capsular bag. During this maneuver there was a sudden deepening of the posterior chamber, which indicated that the capsule defect had enlarged. Viscoelastic was injected around and under the nucleus to support it, and the phaco probe was introduced into the eye using low-flow and low-pressure parameters. The nucleus was engaged with the phaco probe, but vitreous was noted to begin prolapsing anteriorly.
To avoid any vitreous traction and retinal stress, the decision was made to stop the anterior surgery and switch to a pars plana approach. Before withdrawing the phaco probe from the eye, dispersive viscoelastic was injected via the paracentesis into the anterior chamber. The corneal incision was sutured, and the pars plana vitrectomy and lensectomy were started. The surgery went very well with complete removal of the lens nucleus and vitreous. The prior superior retinal detachment was noted to have recurred, and it was successfully addressed as well. For IOL placement, the remaining capsular support was deemed to be insufficient for a sulcus IOL. While we could have placed an anterior chamber IOL, an iris-fixated IOL or a sclerally fixated IOL, we opted to leave the patient aphakic for the best long-term stability.
The patient did very well postoperatively, recovering a best corrected vision of 20/30 with a fully attached and stable retina. He resumed his daily activities with the help of new spectacles. The great outcome in this patient is the result of a detailed consultation, careful preoperative planning, a conservative surgical approach and teamwork to ensure the best care.
- For more information:
- Uday Devgan, MD, is in private practice at Devgan Eye Surgery, Chief of Ophthalmology at Olive View UCLA Medical Center and Clinical Professor of Ophthalmology at the Jules Stein Eye Institute, UCLA School of Medicine. He can be reached at 11600 Wilshire Blvd. #200, Los Angeles, CA 90025; email: email@example.com; website: www.DevganEye.com.
Disclosure: Devgan reports no relevant financial disclosures.