Man presents for refractive surgery consultation
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A 36-year-old Hispanic man presented to the refractive surgery clinic at the New England Eye Center for surgical consultation. He was motivated to be free of contact lenses and glasses.
Ocular history was significant for 10 years of soft contact lens wear for 3 hours per day, 2 days per week, on average. He denied any history of eye trauma or eye surgery. Medical history was notable for hyperlipidemia and obesity; he had no history of keloid scars or oral herpes. Family history was negative for ocular disease. Social history included occupation as a construction worker, with minimal computer work but significant time spent on his phone. His hobbies included soccer and gym workouts. He denied any upcoming travel plans, pets or children.
Examination
Best corrected visual acuity with myopic correction measured 20/30+2 in the right eye and 20/80-2 in the left eye. Refraction was –15.25 +1.50 × 005 in the right eye and –16.75 +1.75 × 155 in the left eye. Pupils were unremarkable in both eyes with no relative afferent pupillary defect. Confrontation visual fields were full, and extraocular motility was normal in both eyes. IOP measured 15 mm Hg in both eyes by Goldmann applanation tonometry.
Anterior segment examination revealed mild blepharitis and meibomitis in both eyes, nasal pinguecula in both eyes and a clear lens in both eyes. The right cornea was clear. The left cornea was noted to have two round paracentral areas of posterior stromal haze with overlying superficial neovascularization located nasally and superotemporally, with mild thinning in the superotemporal area. Posterior segment examination showed myopic fundi in both eyes with posterior staphylomas, tilted optic discs and severe peripapillary atrophy, and diffuse white without pressure and dark without pressure in both eyes. Furthermore, the right eye showed mild mottling of the retinal pigment epithelium (RPE) in the macula and a vitreous tuft at 6 o’clock; the left eye showed evidence of severe myopic degenerative changes, without choroidal neovascular membrane or hemorrhage (Figure 1).
Workup and surgical planning
Outside records were requested to compare BCVA and refraction from the patient’s last eye exam 1 year prior, which noted a history of high myopic degeneration in both eyes, lattice degeneration of the left eye treated with laser retinopexy 12 years ago, and a history of left orbital trauma 4 years ago resulting in fractures of the medial and inferior walls, commotio retinae, and choroidal rupture vs. choroidal neovascularization related to myopic degeneration treated with two intravitreal Avastin (bevacizumab, Genentech) injections. His BCVA post-trauma was documented as 20/70 in the left eye, with a stable refraction. The patient’s provided history regarding the trauma was unreliable.
Pentacam corneal topography (Oculus) showed central corneal thicknesses of 519 µm and 516 µm in the right and left eyes, respectively. Keratometry values were 43.8 D (K1) and 44.5 D (K2) with corneal astigmatism of 0.7 D in the right eye and 43.2 D (K1) and 45.6 D (K2) with corneal astigmatism of 2.4 D in the left eye. Topographic maps showed against-the-rule astigmatism with skew in the right eye and oblique astigmatism in the left eye, with normal Belin/Ambrósio enhanced ectasia total derivation indices in both eyes (Figure 2). Endothelial cell density measured 2,890 cells/mm2 and 2,762 cells/mm2 in the right and left eyes, respectively (Figure 3). IOLMaster 700 (Zeiss) calculations showed axial lengths of 29.26 mm and 30.48 mm in the right and left eyes, respectively, with white-to-white measurements of 11.8 mm and 11.9 mm. Anterior chamber depth was 3.41 mm in the right eye and 3.62 mm in the left eye measured from the corneal endothelium to the anterior surface of the crystalline lens based on Scheimpflug photography on Pentacam. Based on these measurements, the patient met the minimum endothelial cell requirements for the EVO Visian Implantable Collamer Lens (ICL, STAAR Surgical).
The refractive surgery plan was for a posterior chamber phakic IOL for the right eye first, followed by the left eye. The toric EVO Visian ICL was selected to treat the patient’s manifest astigmatism, with this model benefiting from a central port that eliminates the need for a laser peripheral iridotomy. The model comes in four sizes, and the 12.6 mm ICL was selected based on the calculations from STAAR Surgical toric ICL software using the white-to-white horizontal distance and anterior chamber depth measurements. LASIK, PRK and SMILE were contraindicated given the extent of myopic treatment required in already thin corneas, which would result in an unacceptably low residual stromal bed and excessively flat keratometry. Refractive lens exchange was not an option in this young patient with high myopic degeneration due to removal of accommodative ability and increased risk for retinal tears.
Before surgery, the patient was referred to the retina service for evaluation. OCT of the macula revealed a normal macular contour in the right eye and a relatively normal contour with atrophy of the RPE and outer retina in the left eye but no active choroidal neovascular membrane (Figure 4). Laser retinopexy was performed in both eyes, and the limited visual potential in the left eye due to macular atrophy was discussed.
The patient underwent placement of a toric EVO Visian ICL in the right eye, and by postoperative week 1, the uncorrected visual acuity was 20/40-3, with pinhole to 20/30-3, and the ICL was in good position. The team then proceeded with a toric EVO Visian ICL placement in the left eye. The postoperative day 1 uncorrected vision in the left eye was 20/70, with no improvement on pinhole. IOP was 15 mm Hg. On exam, the cornea had stable stromal haze and superficial neovascularization temporally with a 10-0 nylon suture at the incision; the ICL was partially displaced inferotemporally and touching the natural lens superiorly, but no phacodonesis was noted (Figure 5).
What is your diagnosis?
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Dislocated ICL
The most likely etiology for this spontaneous early dislocation of the ICL was a weak posterior chamber support system due to a history of trauma. The patient’s high axial myopia may have also contributed to a weak support system; however, he had no issues in the other eye. He had no history of surgery, no pseudoexfoliation, no connective tissue disease and no retinitis pigmentosa. It was also important to consider improper sizing of the ICL, postoperative trauma or eye rubbing, which the patient denied, or ICL friction due to zonular fibers, which would be unlikely to occur so quickly the day after surgery, especially given the absence of phacodonesis and the placement of the ICL haptics in the sulcus.
Management
The following week, the toric ICL remained with stable dislocation. Anterior segment OCT revealed a 386 µm central vault between the crystalline lens and the posterior surface of the dislocated ICL (Figure 6a). Ultrasound biomicroscopy was performed to evaluate the ICL position; however, the scan could not fully capture the ciliary body or zonules to visualize the ICL placement or rule out any anatomical abnormalities (Figures 6b and 6c).
At postoperative month 1, the uncorrected vision in the left eye had worsened to 20/125-1 (with pinhole to 20/60), and exam showed that the toric ICL was now rotated vertically (Figure 7a).
At this point, management options for the patient included observation, repositioning and rotation of the toric ICL, removal of the ICL altogether, or a lens exchange. The decision was made to proceed with an ICL exchange to replace the toric lens with a spherical lens in the event of further rotation. The team elected to upsize the ICL from 12.6 mm to 13.2 mm. Intraoperatively, the sulcus was found to be deeper temporally, necessitating the placement of the ICL with a vertical orientation instead of horizontal to keep it away from the temporal side.
On postoperative day 1 after ICL exchange in the left eye, the patient reported some visual distortion, with uncorrected vision of 20/300 (pinhole to 20/80). The spherical ICL was noted to be partially dislocated inferonasally (Figure 7b). Anterior segment OCT measured a central vault of 363 µm. One week later, the uncorrected vision improved to 20/80-2, with stable mild inferonasal ICL dislocation (Figure 7c) and anterior segment OCT measuring a central vault of 554 µm. One month after surgery, his vision was 20/100-2 with the spherical ICL found to be slightly inferior and again rotated diagonally into a similar orientation as the prior dislocated toric ICL (Figure 7d). After further discussion, the patient elected for observation for the left eye given that his vision was similar to his baseline BCVA. He was satisfied with the vision in the right eye, which measured 20/25.
Discussion
Historically, the search for the optimal tool to correct high myopia has presented many challenges. However, promising developments have emerged in the field of phakic IOLs. The concept of the phakic IOL is the implantation of a new refractive surface inside the eye without altering the two innate refractive structures of the eye, the cornea and the natural crystalline lens. This contrasts with laser corneal ablation surgery to modify the shape and thickness of the cornea or replacement of the natural lens with an IOL such as in cataract surgery or refractive lens exchange. The phakic IOL was first invented in 1953 by Benedetto Strampelli and designed for placement in the anterior chamber, with numerous associated complications. Significant improvements have resulted in today’s modern phakic IOLs, including the Verisyse phakic IOL (Ophtec) approved by the FDA in 2004, the Visian posterior chamber ICL (STAAR Surgical) approved by the FDA in 2005, and the EVO Visian ICL with a central port approved by the FDA in 2022.
Phakic IOL placement is a good refractive option for patients aged 21 to 45 years who meet the minimum requirements for anterior chamber depth (3 mm) and age-dependent endothelial cell density (1,900 cells/mm2 to 3,875 cells/mm2). The benefits include the ability to treat moderate to high myopia and/or astigmatism (sphere: –3 D to –20 D; cylinder: up to 4 D) beyond the treatment ranges of LASIK, PRK or SMILE. Further advantages are that the procedure avoids the dry eye disease and spherical aberrations encountered in corneal ablation surgery, can be performed even in slightly thin or irregular corneas, has a quick recovery with no corneal flap that would preclude active lifestyles, and allows for easy exchange of the lens if needed. The disadvantages of the phakic IOL are an increased risk for cataract, risk for acute pupillary block necessitating the creation of a patent laser peripheral iridotomy or use of a newer central port-containing model, risk for IOL dislocation, symptoms of halo and glare, possibility of low or high vault, accelerated endothelial cell loss and the need to monitor annually, risk for retinal detachment, and the risks associated with intraocular surgery such as infection or inflammation.
Dislocation of an ICL is an exceedingly rare complication and has been described by Zhang and colleagues in their literature review of several cases, most of which were related to ocular trauma. They found that nine out of 10 of these dislocated ICLs required additional surgery for explantation of the lens (two cases) or repositioning of the lens (seven cases). Spontaneous dislocation of an ICL in the absence of trauma is especially rare, with three prior reports in the literature, one of which was attributed to mydriasis induced by oral antidepressants and one due to abnormal ciliary body morphology altering the sulcus anatomy.
The differential for a dislocated ICL includes trauma, weak support system or improper ICL sizing. Predisposing conditions that may increase the risk for posterior chamber instability or zonular weakness include history of trauma, prior surgery, axial myopia, uveitis, retinitis pigmentosa, atopic dermatitis (repeated eye rubbing), connective tissue disorders (pseudoexfoliation syndrome, Marfan syndrome, homocystinuria, Ehlers-Danlos syndrome, Weill-Marchesani syndrome) and diabetes.
The diagnosis of a dislocated ICL involves a detailed clinical examination including slit lamp biomicroscopy to assess the ICL intraocular position, rotation, vault and anterior chamber depth. Diagnostic imaging includes anterior segment OCT to evaluate the vault size, ultrasound biomicroscopy to assess the position of the ICL relative to the ciliary body and sulcus, specular microscopy to measure endothelial cell density, and finally slit lamp photography to document the lens position for comparison at follow-up visits.
Management of a dislocated ICL involves a thorough discussion of options with the patient according to their goals and lifestyle. These options include observation, lens rotation or repositioning, lens explantation or lens exchange. The key factors to consider in lens selection when exchanging a phakic IOL include size, location (ciliary sulcus or iris claw) and type (spherical, toric or presbyopic).
Sizing of the ICL is a critical step in the process of selecting a new lens for ICL exchange. The appropriate size ICL is one that can be positioned to create a vault of 250 µm to 750 µm and avoid complications from friction against other structures such as cataract, pupillary block or corneal endothelial cell loss. The EVO Visian ICL is a new popular single-piece ICL that comes in four sizes (12.1 mm, 12.6 mm, 13.2 mm and 13.7 mm). While there are various methods to calculate the appropriate ICL size, the FDA study utilized the white-to-white horizontal distance method in conjunction with the anterior chamber depth according to the software of STAAR Surgical. Moshirfar and colleagues performed a retrospective study of 73 ICL patients to assess the efficacy of four methods for predicting appropriate ICL size, and they found that the method of ultrasound biomicroscopy sulcus-to-sulcus distance using the Parkhurst nomogram was the best predictor of appropriate ICL size according to ideal postoperative vault measurements.
Location of the ICL is the other crucial factor in obtaining phakic IOL support. Theoretically, there are three locations to place the phakic IOL: the sulcus, the iris via claw fixation or the anterior chamber angle. The EVO Visian ICL and its predecessor, the Visian ICL, are designed to be placed in the sulcus, which provides the aesthetic benefit of making the lens hidden. The downsides of this location include proximity to the natural lens leading to cataract, low or high vault, and risk for pupillary block with the Visian ICL. The Artisan and Artiflex from Ophtec are iris claw lenses that benefit from a one-size-fits-all model but have increased risk for pigment dispersion, a large 6-mm corneal incision and poor aesthetic appearance. Finally, the AcrySof Cachet lens from Alcon was designed for placement in the anterior chamber angle location, but due to excessive risk for endothelial damage, this model did not receive FDA approval.
Case resolution
On follow-up, the patient developed a new asymptomatic hemorrhage in the macula of the left eye and was evaluated by the retina service. OCT of the macula revealed a small defect in Bruch’s membrane and possible choroidal neovascularization nasal to the fovea in the setting of myopic degeneration. Intravitreal injection was considered; however, given the risk of affecting the ICL position due to possibly weak temporal zonules from the previous trauma, the decision was made to observe. At follow-up 6 months after the ICL exchange, uncorrected vision measured 20/25 in the right eye and 20/100 with pinhole to 20/80 in the left eye, and the retinal hemorrhage was resolved. IOP was well controlled on dorzolamide/timolol in the left eye, which had been initiated for an IOP spike postoperatively. The patient endorsed trouble driving at night due to starbursts in the left eye, so the decision was made to switch the dorzolamide/timolol to brimonidine to reduce the pupil size and potentially help minimize the starbursts.
Given the patient’s recurrent ICL dislocations when placed in the ciliary sulcus despite vertical rotation and upsizing the lens, further dislocation would likely require an alternative location for phakic IOL support. If additional surgery were indicated, the next option would be to perform an ICL exchange for an iris claw phakic IOL.
This case highlights the challenges of obtaining good phakic IOL support when a rare spontaneous ICL dislocation is encountered, as well as the important role of the surgeon in guiding the refractive patient at every step of the journey to ensure his or her lifestyle goals are achieved.
- References:
- Alfonso JF, et al. J Refract Surg. 2019;doi:10.3928/1081597X-20190118-01.
- Espinosa-Mattar Z, et al. Ophthalmic Surg Lasers Imaging. 2012;doi:10.3928/15428877-20120712-04.
- EVO/EVO+ VISIAN Implantable Collamer Lens – P030016/S035. https://www.fda.gov/medical-devices/recently-approved-devices/evoevo-visian-implantable-collamer-lens-p030016s035. Updated April 18, 2022.
- Kaufer RA, et al. J Cataract Refract Surg. 2005;doi:10.1016/j.jcrs.2005.04.015.
- Kong J, et al. Ophthalmology. 2010;doi:10.1016/j.ophtha.2009.09.010.
- Moshirfar M, et al. J Refract Surg. 2022;doi:10.3928/1081597X-20211109-01.
- Moshirfar M, et al. Open Ophthalmol J. 2014; doi:10.2174/1874364101408010024.
- Phakic IOLs: An overview. https://crstodayeurope.com/articles/2013-may/phakic-iols-an-overview/. Published May 2013.
- Phakic IOLs for high myopia: History and evolution. https://millennialeye.com/articles/july-aug-19/phakic-iols-for-high-myopia-history-and-evolution/. Published July/August 2019.
- Schmitz JW, et al. J Refract Surg. 2012;doi:10.3928/1081597X-20120410-02.
- Song JS, et al. J Cataract Refract Surg. 2005;doi:10.1016/j.jcrs.2005.01.024.
- Takagi Y, et al. Clin Case Rep. 2019;doi:10.1002/ccr3.2055.
- Wang R, et al. Digit J Ophthalmol. 2019;doi:10.5693/djo.02.2019.09.002.
- Zhang L, et al. Int J Ophthalmol. 2023;doi:10.18240/ijo.2023.01.20.
- For more information:
- Edited by Jonathan T. Caranfa, MD, PharmD, and Angell Shi, MD, of New England Eye Center, Tufts University School of Medicine. They can be reached at jcaranfa@tuftsmedicalcenter.org and ashi@tuftsmedicalcenter.org.
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