Abstract
An adolescent female with underlying bilateral pseudophakia and idiopathic intermediate uveitis had reduced visual acuity due to posterior capsule opacification (PCO). The rapid progression and different morphological formations of Elschnig pearls were not influenced by the uveitis and immunosuppressive treatment. No capsulotomy was performed, and the PCO regressed spontaneously over time.
Keywords: ophthalmology, anterior chamber
Background
Defined as an opaque layer of tissue that forms on the lens posterior capsule behind the intraocular lens (IOL), posterior capsule opacification (PCO) is one of the most common sequelae of cataract surgery.1 The incidence of PCO is known to range from as high as 40% to as low as 20% in patients 2–5 years after cataract surgery.2 Previous research has established that the incidence of PCO increases with younger age, diabetes mellitus, uveitis and traumatic cataracts,3–5 whereas, certain surgical methods and types of IOL are known to reduce the incidence of PCO. Additionally, the use of cold irrigation balance salt solution during cataract surgery has been shown to cause a less traumatic surgical procedure.6
PCO is generated by lens epithelial cells (LECs) that remain in the lens capsular bag after cataract surgery. The wound-healing response postcataract surgery triggers the residual LECs to proliferate and migrate across the posterior capsule, where they undergo lens fibre regeneration and epithelial-to-mesenchymal transition. Encroachment of LECs on the central visual axis causes obscuration and leads to decreased visual acuity. The higher incidence of PCO in the younger age group is due to a higher LECs rate of proliferation capacity as compared with adults. Whereas, in patients with diabetes mellitus and concomitant ocular pathologies, the postcataract surgery inflammatory response is intense due to the impaired blood–aqueous barrier. The resulting chemical mediators stimulate LECs mitotic activity, which eventually leads to PCO formation. PCO may appear as Elschnig pearls, fibrosis, Soemmering rings or capsular wrinkling.
The treatment of vision impairment due to PCO is Nd:YAG laser posterior capsulotomy, although spontaneous regression of PCO has been reported.7 8 We report a case of rapid progression and different evolutions of Elschnig pearls despite being on immunosuppressive therapy.
Case presentation
An adolescent female with underlying bilateral pseudophakia and idiopathic intermediate uveitis (IU) developed rapid progression of Elschnig pearls regardless of being on immunosuppressive therapy.
Her IU was complicated by high intraocular pressure secondary to corticosteroid use, which was controlled with topical anti-glaucoma eyedrops. She had a history of vision-limiting band keratopathy, which required EDTA chelation 4 years prior to cataract surgery.
She developed cataracts in both eyes (posterior subcapsular cataract 2+ and nuclear sclerosis 1+) with a best corrected visual acuity (BCVA) of 4/60 in the right eye and 3/60 in the left eye, 4 years after the diagnosis of IU. She underwent continuous curvilinear capsulorhexis, lens aspiration and complete-in-the-bag implantation of a single-piece hydrophobic acrylic IOL, and her BCVA improved to 6/24 in both eyes.
Preoperatively and postoperatively, she continued with topical dexamethasone 0.1%, systemic prednisolone and mycophenolate mofetil therapy. On average, she received intravitreal Ozurdex (dexamethasone) every 3 months for each eye to control her IU. She had a total of seven intravitreal Ozurdex injections for each eye, three preoperative and four postoperative.
At 14 months postcataract surgery, an incidental finding of newly formed Elschnig pearls was noted in both eyes during her 2 weekly follow-ups for IU stabilisation. For the right eye, Elschnig pearls started to form from the nasal side of the posterior capsule (figure 1A). The pearl’s appearance was small and round. From then onwards, the Elschnig pearl formation progressed toward the visual axis over a period of 3 months (figure 1B,C) before coming to a halt (BCVA 6/36) (figure 1D).
Figure 1.
Retroillumination of the anterior segment of the right eye shows the Elschnig pearls. Note the formation of Elschnig pearls on the nasal side of the posterior capsule that progressed toward the visual axis. (A) 14 months postcataract surgery. (B) 14 months and 2 weeks postcataract surgery. (C) 15 months postcataract surgery. (D) 17 months postcataract surgery.
In the left eye, Elschnig pearls started from the inferonasal and superotemporal sides (figure 2A), and gradually coalesced at the visual axis over a period of 3 months (figure 2B,C). The pearls’ appearance was variable in size and shape. Thenceforth, Elschnig pearls started to resolve at the visual axis and remained solidified at the side of the posterior capsule (BCVA 6/24) (figure 2D).
Figure 2.
Retroillumination of the anterior segment of the left eye shows the Elschnig pearls. Note the formation of Elschnig pearls on the inferonasal and superotemporal sides of the posterior capsule, which gradually coalesce at the visual axis over a period of 3 months before resolving. (A) 14 months postcataract surgery. (B) 14 months and 2 weeks postcataract surgery. (C) 15 months postcataract surgery. ((D) 17 months postcataract surgery.
Throughout the period of Elschnig pearls observation, the degree of IU was 1+ of cells in the anterior chamber and 1+ to 2+ of cells in the vitreous cavity. She required a supplemental dose of intravitreal Ozurdex in each eye to control the IU. There was no change in Elschnig pearls’ progression with the addition of intravitreal Ozurdex injections.
Outcome and follow-up
In the fourth month of Elschnig pearls observation, her vision improved to baseline BCVA 6/24 bilaterally. She did not proceed with the Nd:YAG laser posterior capsulotomy due to signs of Elshnig pearl regression at the visual axis, and the fundus view was not obstructed by the PCO.
Discussion
The incidence of PCO formation following cataract surgery in uveitic patients ranges from 35.5% to 50.9%.4 9 Despite several preventive interventions such as continuous curvilinear capsulorhexis, in-the-bag capsular fixation of optic and haptics, and hydrophobic acrylic IOL use, this patient developed PCO. The period between cataract surgery and the development of PCO in this patient was 14 months. This is in line with previous studies on uveitic patients, which reported PCO formation 14.9–17.2 months postoperatively.9
The morphological short-term changes of Elschnig pearls in both eyes were studied in this case report. We found noticeable changes in pearls between every follow-up examination in each eye. The shape, size and number of Elschnig pearl emergences and disappearances varied between eyes. On the right eye, there was little regression after the formation of Elschnig pearls, while on the left, there was a highly active progression and regression of Elschnig pearls. This finding is consistent with that of Findl et al, who reported that the rate of formation and disappearance of pearls may occur within 1 week.10
This case reports the rapid progression and different evolution of Elschnig pearls in different eyes of the same patient. This highlights that it is possible to observe different patterns of Elschnig pearls in the absence of variable factors. As manifested in this case, both eyes had the same severity of IU and received the same IOL material and immunosuppressive medications.
Although it is known that there is a strong relationship between PCO and uveitis,3 there has been no report on the association between the severity of uveitis and the dynamic behaviour of PCO development. This case demonstrated that the severity of uveitis did not have an effect on the Elschnig pearls’ pattern of emergence and disappearance. Uncontrolled inflammation postoperatively may cause PCO; therefore, surgical techniques that reduce intraoperative inflammation should be implemented to decrease the incidence of PCO. The use of cold balance salt solution intraoperatively may also help in reducing postop inflammation.11
The findings in regards to corticosteroids as a pharmacological prevention of PCO have been inconclusive. For example, some studies showed that corticosteroids did not prevent the formation of PCO, while other studies indicated the usage of corticosteroids was associated with a lower rate of PCO.12 13 Steroids indirectly inhibit cyclo-oxygenase and prevent the production of inflammatory mediators such as prostaglandin. A decrease in inflammatory reactions prevents activation of antiapoptotic pathways and may possibly limit LECs proliferation. In reviewing the literature, no data was found on the association between Ozurdex and PCO formation. This case reports the formation of PCO despite multiple Ozurdex injections.
Caballero et al suggest three theories for the spontaneous regression of Elschnig pearls: first, Elschnig pearls fall through the posterior capsulotomy into the vitreous; second, phagocytosis of Elschnig pearls by vitreous macrophages; and third, apoptosis or cell autolysis.14 15 This case report supports the third theory of Cabalerro et al: LECs’ capacity to proliferate and migrate will eventually cease with time, before they undergo apoptosis and disappear.
Patient’s perspective.
I was initially diagnosed with inflammation of the eyes during my teenage years. At that point in time, I did not really understand what was happening. Most of the time, the attending doctors would discuss my illness and treatments with my mother. As I grew older, I was included more in the discussion, and I slowly came to understand that my inflamed eyes were difficult to control without medications and that each medication has its own side effects. With my mother’s support, I managed to get through the obstacles.
When the doctor broke the news to me regarding the opacification behind my implanted lens, I was initially upset. The possibility of living my life with poor vision made me dread it. Fortunately, the attending doctor explained to me that there was a solution to it; a laser treatment, should the opacification worsen. It gave me peace of mind to know that there was a treatment for it should the worse happen.
The doctors monitor my condition carefully and ask at every check-up if my vision is interfering with my daily activities. So far, it hasn’t affected my life. To my surprise, the lens opacification lessened on its own over subsequent follow-ups. I am grateful for it and I hope it stays that way.
Learning points.
The Elschnig pearls’ formation and spontaneous resolution can occur over a short period of time.
Clinicians should provide a reasonable waiting period to ensure no spontaneous posterior capsule opacification (PCO) resolution prior to proceeding to the Nd:YAG laser.
There is no association between the severity of uveitis and the rate of Elschnig pearls’ progression and regression.
Long-term usage of steroids does not prevent the formation of PCO.
Acknowledgments
We would like to thank the Director General of Health Malaysia for his permission to publish this article.
Footnotes
Contributors: SFAB collect data, write the case report and obtain patients’ consent. AMLK, TC and OO provide comments on the report and guidance.
Funding: The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.
Competing interests: None declared.
Provenance and peer review: Not commissioned; externally peer reviewed.
Ethics statements
Patient consent for publication
Consent obtained directly from patient(s)
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