CASE PRESENTATION
A 75-year-old man is referred for poor vision after cataract surgery. According to the patient, surgery took place about 2 months ago. Preoperatively, he wanted to maintain his ability to read without correction but was willing to wear glasses for distance. Upon presentation, the patient can read only when the material is held close to his nose.
On examination, his UCVA is counting fingers OU, and his BCVA is approximately 20/100 OU with a refraction of -12.00 D spherical equivalent. The patient has severe kyphosis, which prevents him from straightening his neck, making a slit-lamp examination challenging, and renders diagnostics almost impossible. The limited examination that can be performed shows significant epithelial basement membrane dystrophy (EBMD; Figure 1) in both eyes. The posterior chamber IOL in each eye appears to be inside the capsular bag, but patient positioning makes a detailed assessment impossible. Biometry and topography are attempted but cannot be performed. B-scan ultrasound of the retina in each eye finds no abnormalities.
Figure 1. Representative image of severe EBMD. Both of the patient’s eyes are similar in appearance.
When contacted, the patient’s original surgeon confirms that the target refraction was -2.25 D and a 21.00 D IOL was placed in each eye.
The patient agrees to undergo a superficial keratectomy in each eye to address the irregular ocular surface. The procedure is performed with great difficulty. After the eyes heal, a repeat manifest refraction confirms a highly myopic result after cataract surgery, but the patient’s BCVA has improved to about 20/50. His inability to hold his head straight greatly increases the vertex distance from the phoropter to the eye.
The patient is anxious to improve his uncorrected near visual acuity. The ocular surface is now healthy enough to allow his high myopia to be addressed. How would you plan surgery based on the limited examination?
Once the patient is positioned in the OR (Figure 2A), you see the IOL for the first time (Figure 2B). How would you manage the implant?
Figure 2. Severe kyphosis of the neck prevents the patient from lying flat on his back. Even with the foot of the stretcher elevated as high as it can go, his head cannot be positioned parallel to the floor (A). Under the microscope (note the slight head-down position), the IOL is seen for the first time. There appears to be a discontinuous anterior capsulorhexis, and a haptic may be in the sulcus (B).
—Case prepared by Brandon D. Ayres, MD
ARIEL CHEN, MD
Before intervening surgically, I would discuss the nonsurgical options of spectacle correction and contact lenses with the patient. His poor BCVA may be caused by minification from a highly myopic refraction that contact lenses could improve. Given the variability of IOL exchange techniques selected intraoperatively, if the patient is motivated to undergo surgery, he would be counseled on the possibility that capsular compromise could necessitate a vitrectomy or the scleral fixation of an IOL.
After an examination of the eye under the OR microscope (Figure 2B), the iris would be retracted with either a Sinskey hook or an iris hook to identify the location of the haptic not visualized. The capsule would be viscodissected from the IOL. Once the IOL is mobile, it would be manipulated into the anterior chamber, cut into pieces, and removed.
Given the discontinuous anterior capsulorhexis, I suspect it would not be possible to place an IOL inside the capsular bag. If my suspicion proves to be correct and the remaining capsule is stable, a posterior capsulorhexis and anterior vitrectomy could be carefully performed. Then, the IOL could be placed in the sulcus with optic capture. Another option would be to suture the IOL to the iris. The first strategy would be my preference owing to the risk of postoperative inflammation with iris fixation.
With regard to IOL power, in light of the earlier refractive surprise, intraoperative aberrometry would be performed.
DEREK W. DELMONTE, MD
This case highlights the challenge of obtaining a desirable refractive outcome when preoperative planning is limited for any reason. An inability to obtain accurate biometry readings, perform a reliable manifest refraction, or conduct an adequate slit-lamp examination due to patient anatomy (kyphosis) all contributed to the highly myopic result. It would be imperative to explain to the patient that achieving his desired refractive outcome remains challenging.
When planning additional surgery, I would be prepared for an IOL exchange to be necessary. As for determining the proper IOL power, the advantages include the treated cornea and the known power of the current implant. Confirming the refraction with retinoscopy and loose lenses might help provide a more accurate result without the problem of increased vertex distance. If the patient’s refractive state is confirmed to be more myopic than intended, a rough estimate of the new IOL power could be obtained by multiplying the amount of additional myopia (in diopters) by 1.2 and subtracting it from the 21.00 D lens implanted. For example, if a -12.00 D outcome is confirmed and the intended outcome is -2.00 D, the estimate would be as follows: 21.00 D - (10.00 D error x 1.2) = ~9.00 D lens. Intraoperative biometry capabilities would also be helpful in this situation.
Figure 2B indicates that an IOL exchange for a 9.00 D three-piece lens in the sulcus would be the safest option, particularly if the procedure is not performed by the original surgeon, who may have a better idea of the capsular support available.
MARISA SCHOEN, MD
A smaller refractive error could be corrected with laser vision correction. The procedure is contraindicated, however, by the patient’s high myopia, severe kyphosis, and history of EBMD. An IOL exchange could be considered after appropriate patient expectations are set and he has been counseled on the procedure’s risks.
It is unclear why the patient’s BCVA is only 20/50 after the superficial keratectomy. Measurements with a retinal acuity meter would be obtained to assess his vision potential, and a refraction with loose lenses would be performed.
To calculate the lens power for a bag-to-bag IOL exchange, manual keratometry and immersion ultrasound biomicroscopy would be performed, and the refraction data obtained with loose lenses would be entered into the Barrett RX formula to mitigate inaccuracies from poor patient positioning at the phoropter. I would expect the keratometry (K) readings to be different after the superficial keratectomy. Nevertheless, I would review the preoperative measurements and IOL calculations from the initial surgeon and compare them to my measurements. I would feel more confident if there is a difference in K readings and axial length that can explain the patient’s myopic error.
Figure 2B shows a one-piece IOL with at least one haptic in the sulcus and significant fibrosis of the capsule beneath. The IOL would be carefully dissected from the capsular bag, elevated into the anterior chamber, bisected, and removed. An attempt would be made to place a new IOL in the bag. If, however, the capsular bag cannot be dissected open safely and reinflated, then a posterior capsulotomy would be performed, and a three-piece IOL would be implanted in the sulcus with optic capture.
TANYA TRINH, MBBS, FRANZCO
It would be important to set realistic patient expectations because challenges with surgical positioning and biometry and the patient’s prior complicated IOL surgery add several layers of complexity.
His ocular surface has been optimized. Keratometry, immersion A-scan ultrasound, and IOL calculations could be performed intraoperatively to confirm the IOL power.
Maximal Trendelenburg bed positioning should be employed, and the surgeon should be aware of the reduced bed-to-floor height. The microscope head could be rotated to allow an en face view of the eye, and the objective lens might have to be exchanged to account for the altered scope-to-eye distance. This is a scenario where the heads-up 3D display from the Zeiss Artevo 800 (Carl Zeiss Meditec) or Ngenuity 3D Visualization System (Alcon) would be particularly useful because it would allow the surgeon to operate in an otherwise ergonomic position. The ophthalmologist, however, would still have to adjust the positioning of their hands to account for the head tilt.
The discontinuous capsulorhexis and displaced one-piece IOL with potential tilt from a haptic in the sulcus should be explored. Only 8 weeks have elapsed since the last surgery, so it may still be possible to open the bag gently and preserve it, remove the one-piece IOL, and implant a new lens. The risks, however, of an unstable capsular bag and an errant capsular tear are high with additional intraoperative manipulation.
My approach would be to preplace pars plana ports for a vitrectomy and, if the capsular bag–IOL complex is indeed unstable, remove it and perform four-point fixation of a hydrophobic four-loop IOL such as the LuxGood (Bausch + Lomb; off-label use) or Micropure (BVI) with intrascleral passes of a PTFE suture (Gore-Tex, W.L. Gore & Associates) to reduce the risk of erosion. In my experience, this strategy provides exceptional long-term stability with no tilt—particularly beneficial in situations like this one where a return to the OR would be difficult.
Alternatively, after the original IOL is removed and the integrity of the posterior capsule is confirmed, a posterior capsulorhexis could be constructed, and a three-piece monofocal lens could be inserted in the sulcus. Posterior optic capture could be performed to prevent IOL rotation or migration, assuming only the integrity of the anterior capsule has been compromised.
WHAT I DID: BRANDON D. AYRES, MD
After conducting the most detailed examination possible, I had a long discussion with the patient during which I outlined the risks and benefits of surgery. The plan was to take him to the OR for an examination under anesthesia, axial length measurements, K readings, and probably an IOL exchange.
In the OR, the lightly sedated patient was positioned as comfortably as possible. The diagnostics team then obtained K readings and axial length measurements in both eyes. IOL calculations were performed using the new data and a refractive target of -2.00 D OU (Figure 3). Based on the calculations, I decided to perform an IOL exchange in the left eye.
Figure 3. IOL calculations for both eyes with a target refraction of -2.00 D. Each eye has a +21.00 D lens implant.
Two paracentesis incisions and a temporal incision were made (Figure 4). The capsulorhexis seemed to have a nasal defect, and capsular adhesions were visible superiorly. The capsular bag was opened carefully with an OVD, and the original IOL was brought into the anterior chamber, cut into multiple pieces, and removed. The area of capsular fibrosis was dissected away to open the capsular bag. Upon inspection, the capsular bag appeared to be capable of holding a one-piece acrylic IOL, with the haptics covered by the anterior capsule. The IOL was placed and rotated into position, and the OVD was removed with the I/A handpiece. The incisions were hydrated and found to be watertight. The patient was discharged and asked to return the next day.
Figure 4. The appearance of the patient’s left eye on presentation. Note the discontinuity of the capsulorhexis and superior fibrosis (A). After viscodissection, the IOL is rotated into the anterior chamber (B) and cut into small pieces for removal (C). The area of capsular fibrosis is carefully dissected free with microforceps (D), which allows a new one-piece acrylic IOL to be implanted (E). Final appearance of the IOL. The haptics are within the bag and covered by anterior capsular leaflets to prevent chafing of the iris (F).
One day after surgery, the patient’s uncorrected distance visual acuity was 20/100, and his uncorrected near visual acuity was J1.
He is thrilled with his ability to read at a comfortable working distance, and surgery on his right eye is being planned.
