From the Department of Ophthalmology, University of Oklahoma College of Medicine, Oklahoma City, Oklahoma.
Supported in part by an unrestricted grant from Research to Prevent Blindness to the the Dean McGee Eye Institute and the Department of Ophthalmology, University of Oklahoma.
The authors have no financial or proprietary interest in the materials presented herein.
Address correspondence to Donald U. Stone, MD, 608 S.L. Young Boulevard, Oklahoma City, OK 73104. E-mail: Donald-Stone@dmei.org
The high incidence of posterior capsular opacification following cataract surgery is well described in patients with retinitis pigmentosa.1,2 Cataract surgery in patients with retinitis pigmentosa can also be complicated by excessive fibrosis and contracture of the anterior capsule.3–5 There have been several hypotheses proposed to explain this association, including increased lens epithelial cell proliferation and zonular insufficiency. We present a case of acute bilateral anterior capsule phimosis in a patient with retinitis pigmentosa after uncomplicated phacoemulsification with a continuous curvilinear capsulorrhexis and single-piece acrylic intraocular lens (IOL) implantation. The onset of capsular contraction in this patient was more rapid than any case we could identify in the literature, and may have implications for surgical planning, technique, and follow-up.
A 43-year-old man with retinitis pigmentosa with classic findings (retinal pigment epithelial atrophy and migration, optic nerve pallor, retinal vascular attenuation, and constriction of visual fields in both eyes) presented with recent difficulty with visual tasks. Examination revealed a best-corrected visual acuity of 20/70 in the right eye and 20/60 in the left eye with −7.50 spherical refraction in both eyes; slit-lamp examination revealed a posterior subcapsular cataract in each eye. Cataract surgery was performed in the left eye, followed by identical surgery in the right eye 15 days later. The procedure used was clear cornea phacoemulsification with a 4.5- to 5-mm continuous curvilinear capsulorrhexis and a single-piece acrylic AcrySof SN60WF IOL (Alcon Laboratories, Fort Worth, TX) posterior chamber IOL was placed in the capsular bag. No intraoperative phacodonesis was noted and no intracameral injection was administered. On the first postoperative day, the patient was found to be more myopic in the left eye than expected based on preoperative immersion A-scan calculations with a spherical equivalent of −2.50, but no other abnormalities were noted; the patient did not undergo pupillary dilation at the first postoperative visit. The postoperative drop regimen was nepafenac 0.1% (Nevanac; Alcon Laboratories), prednisolone acetate 1% (Pred Forte 1%; Allergan, Irvine, CA), and moxifloxacin 0.5% (Vigamox; Alcon Laboratories), all used four times daily for 1 week and tapering thereafter.
By postoperative day 17 for the left eye, the patient presented complaining of worsening blurry vision in his left eye since his first postoperative visit. On examination, the patient was found to have anterior capsular contracture with complete occlusion of the anterior capsulotomy; the lens haptics were bent forward and inward. Anterior chamber examination revealed 2+ pigmented cells in the left eye; the right eye was examined on postoperative day 2 and demonstrated 4+ pigmented cells. There was no indication of endophthalmitis such as vitreous cells or hypopyon, and after opening the left anterior capsule with the YAG laser there was no cystoid macular edema noted.
On postoperative day 21 for the right eye, the patient presented with decreased visual acuity in the right eye. Visual acuity was found to be 20/125, which did not improve with refraction. Severe anterior capsule phimosis with inward distortion of the lens haptics, similar to the left eye prior to laser, was noted. The YAG laser was again used in the same fashion as in the left eye. The figure demonstrates the appearance of the anterior lens capsule and IOL after laser treatment, with residual distortion of the lens haptics in the capsular bag. At the last postoperative visit, corrected visual acuity in both eyes was 20/40 with spectacles. No pseudophakodonesis was visible in either eye and both eyes had stabilized within 0.5 diopters of expected refractive outcome.
Figure. Slit-Lamp Photography of the Right Eye After Anterior Capsulotomy with a YAG Laser.
Although the exact etiology of capsular phimosis following cataract surgery in patients with retinitis pigmentosa is unknown, there are two hypotheses. First, cytokines, such as interleukin-6 and interleukin-1, may be more abundant in eyes with retinitis pigmentosa, thereby inducing fibrosis by affecting lens epithelial cells.3 The proposed mechanism is disruption of the blood–aqueous barrier and blood–retina barrier in eyes of patients with retinitis pigmentosa. This may allow increased release of circulating cytokines into the aqueous humor. Activation of lens epithelial cells by the cytokines may result in the anterior capsular contraction and increased fibrosis associated with patients with retinitis pigmentosa.3,4 Second, zonular weakness may be responsible because dehiscence of zonules has been postulated to be associated with retinitis pigmentosa.4,5 This weakness may provide less resistance to capsular contracture. Ando et al. also proposed that zonular weakness may lead to wrinkling or folding of the posterior capsule, thereby providing a scaffolding for lens epithelial cell migration.1 Therefore, it is possible that the two potential mechanisms are linked and are either additive or synergistic.
Notably, Ando et al. found no relationship between diabetes mellitus or diabetic retinopathy and the probability of laser posterior capsulotomy.1 For this reason, they question the compromised blood–ocular barrier function as a sole contributor to the increased risk for posterior capsulotomy in patients with retinitis pigmentosa. They also found that the number and viability of lens epithelial cells was greater in immature cataracts when compared with advanced cataracts. This may be relevant given the younger age of onset of cataract in patients with retinitis pigmentosa.
Although there is disagreement as to the mechanism, there is little doubt that patients with retinitis pigmentosa are more susceptible to capsular opacification, contracture, and phimosis after cataract surgery with continuous curvilinear capsulorrhexis. Several studies have reported an association of retinitis pigmentosa with in-the-bag IOL dislocation.1–6 Sudhir et al. reported a patient with retinitis pigmentosa with severe anterior capsule fibrosis and contraction of the capsulorrhexis opening 4 months after surgery.5 Hayashi et al. reported that 10.5% of patients with retinitis pigmentosa experienced in-the-bag IOL dislocation following implantation.6 However, it is worth noting that these patients did not experience IOL dislocation until several years after cataract surgery, and this was thought to depend on slowly progressive dehiscence of zonules.6 However, we found no reports of rapid anterior capsular phimosis similar to what occurred in our patient. This case highlights the consideration that must be given to techniques to prevent or minimize capsular contracture following cataract surgery in patients with retinitis pigmentosa.
The symmetric behavior of the lens capsule after surgery in our patient implies a predisposition to capsular contraction beyond most patients with retinitis pigmentosa; it is plausible that certain variants of retinitis pigmentosa have a greater risk of certain complications, or that the IOL material or design may have an impact on capsular contracture. In this case, a single-piece foldable IOL was used. Using a three-piece IOL, a capsular tension ring,5 or intraoperative radial relaxing incisions in the anterior lens capsule after lens implantation may be useful methods to minimize or eliminate the abovementioned complications in patients with retinitis pigmentosa undergoing cataract surgery. We recommend that if none of these modifications in technique are employed then physicians should be cognizant of the complications likely to occur in patients with retinitis pigmentosa and closely monitor for these developments. Our case also illustrates that YAG capsulotomy can be effective in treating the anterior capsular phimosis resulting from cataract surgery in patients with retinitis pigmentosa.5 These steps may also prevent the potential complication of IOL dislocation into the vitreous, although longitudinal prospective studies will be necessary to confirm this hypothesis.
- Ando H, Ando N, Oshika T. Cumulative probability of neodymium: YAG laser posterior capsulotomy after phacoemulsification. J Cataract Refract Surg. 2003;29:2148–2154. doi:10.1016/S0886-3350(03)00353-5 [CrossRef]
- Smith M, Pappas G, Evans N. Intraocular lens migration following posterior capsulotomy in retinitis pigmentosa. Eye. 2007;21:867–869. doi:10.1038/sj.eye.6702739 [CrossRef]
- Nishi O, Nishi K. Intraocular lens encapsulation by shrinkage of the capsulorhexis opening. J Cataract Refract Surg. 1993;19:544–545.
- Hayashi K, Hayashi H, Matsuo K, Nakao F, Hayashi F. Anterior capsule contraction and intraocular lens dislocation after implant surgery in eyes with retinitis pigmentosa. Ophthalmology. 1998;105:1239–1243. doi:10.1016/S0161-6420(98)97028-2 [CrossRef]
- Sudhir RR, Rao SK. Capsulorrhexis phimosis in retinitis pigmentosa despite capsular tension ring implantation. J Cataract Refract Surg. 2001;27:1691–1694. doi:10.1016/S0886-3350(01)00869-0 [CrossRef]
- Hayashi K, Hirata A, Hayashi H. Possible predisposing factors for in-the-bag and out-of-the-bag intraocular lens dislocation and outcomes of intraocular lens exchange surgery. Ophthalmology. 2007;114:969–975. doi:10.1016/j.ophtha.2006.09.017 [CrossRef]