Corneal Ectasia and Hydrops in Ocular Hypotony: the Corneal Crease

CASE REPORT

Corneal Ectasia and Hydrops in Ocular Hypotony: The Corneal Crease

Asim V. Farooq, MD, Ketki Soin, MD, Samantha Williamson, MD, Charlotte E. Joslin, OD, PhD, Maria S. Cortina, MD, and Elmer Y. Tu, MD

corneal curvature. Usually, the area of greatest steepening is Purpose: To report the association of chronic ocular hypotony with paracentral or inferior; the topographic patterns among ectatic the development of progressive corneal ectasia and hydrops. diseases are thought to comprise a spectrum of manifestations 1,2 fi Methods: Retrospective case series. of the same disease process. There exists signi cant controversy about the pathophysiology of corneal ectasias, Results: Three patients with ocular hypotony were referred for including the contributions of genetic, inflammatory, and – corneal evaluation and found to have ectasia and acute corneal mechanical factors.3 5 hydrops in their hypotonous eye(s). Clinically, the globes were easily A significant number of patients provide a history of deformable with either external digital palpation and/or simple eye rubbing, although the precise pathophysiology of its blinking. All 3 patients had a history of chronic iridocyclitis, relationship to progressive ectasia is unclear.3 There is including one with juvenile idiopathic arthritis. In each case, the evidence that eye rubbing and pressure exerted by the eyelids area of thinning was narrow and arcuate in configuration, distinctive can cause temporary, reversible changes in corneal curvature from other ectatic disorders. Also uncharacteristically, the acute accentuated by concomitant acute ocular hypotony.6–13 We hydrops resolved rapidly within 2 to 3 weeks without surgical present a unique clinical entity in which permanent corneal intervention. In 1 case, severe thinning with perforation occurred ectasia and associated hydrops developed in the setting of requiring urgent penetrating keratoplasty. chronic, stable hypotony resulting in a pattern of corneal Conclusions: thinning and clinical course distinct from previously This case series demonstrates a unique clinical entity described forms of ectasia. This entity is a cause of significant in which corneal ectasia and hydrops developed in the setting of ocular visual and ocular morbidity and may provide additional hypotony and easily deformable corneas, in a pattern unlike previously insight into the pathophysiology of classic forms of ectasia. described forms of ectasia. Acute hydrops, even with associated corneal perforation, demonstrated a short and self-limited course. Corneal ectasia and irregular astigmatism should be suspected as MATERIALS AND METHODS a cause of unexplained visual loss in the ever-increasing number of The charts of 3 patients with corneal ectasia and patients with chronic, stable ocular hypotony. Further study is thinning in the setting of chronic ocular hypotony were warranted to determine the pathophysiology of corneal ectasia in this reviewed. Case descriptions of each of the 3 patients are given fl setting, which may include mechanical and in ammatory factors. below. This review was performed in accordance with the Key Words: hypotony, ectasia, hydrops, corneal crease, keratoco- Institutional Review Board at the University of Illinois at nus, uveitis Chicago (UIC) and the Declaration of Helsinki. (Cornea 2015;34:1152–1156) CASE REPORTS

nown common corneal ectatic diseases include keratoco- Knus, pellucid marginal degeneration, and postrefractive Case 1 surgery ectasia. These disorders are characterized by irregular A 27-year-old African American man presented with a 1-day astigmatism, progressive corneal thinning, and steepening of complaint of decreased vision and pain in the right eye. He had a history of chronic hypotony OD in the setting of long-standing bilateral idiopathic uveitis, which was previously treated with oral Received for publication March 22, 2015; revision received May 9, 2015; prednisone, triamcinolone injections, and a ﬂuocinolone implant OD accepted May 17, 2015. Published online ahead of print July 10, 2015. approximately 1 year ago. A thorough workup by a uveitis specialist From the Department of Ophthalmology, University of Illinois at Chicago, was unrevealing. The ocular history also included bilateral cataract Chicago, IL. extraction with intraocular lens placement 3 years ago. Visual acuity Supported, in part, by an Unrestricted Departmental Award for Research to at presentation measured hand motions OU. Intraocular pressure Prevent Blindness. ﬂ measurement was initially deferred. The central corneal thickness The authors have no funding or con icts of interest to disclose. m Reprints: Elmer Y. Tu, MD, Department of Ophthalmology, University of (CCT) was 508 m OD and was not measured OS. Illinois at Chicago, 1855 W. Taylor St, M/C 648, Chicago, IL 60612 Anterior segment examination revealed an arcuate area of (e-mail: [email protected]). corneal steepening and edema with a break in Descemet Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved. membrane OD, consistent with corneal hydrops (Fig. 1A), within

1152 | www.corneajrnl.com Cornea Volume 34, Number 9, September 2015

FIGURE 1. A, External photograph of the right eye of case 1 at presentation demonstrating an area of hydrops temporally. B, External photograph of the same eye after less than 2 weeks shows signiﬁcant resolution of hydrops with a residual area of thinning in an arcuate con- ﬁguration. C, Axial topography (Keratron; Optikon 2000, Rome, Italy) of the right eye demonstrating corneal irregularity. D, External photograph of the right eye at follow-up. A bandage contact lens is in place. There is a large area of corneal edema with an area of severe thinning paracentrally corresponding to the smaller air bubble (located between the contact lens and the corneal epithelium). A break in Descemet membrane was seen clinically in the nasal cornea (not at the location of severe thinning).

which was an area of subtle, intermittent Seidel positivity. The 9to3o’clock, consistent with mild corneal hydrops (Fig. 3). The left cornea was opaciﬁed centrally with a large area of band edema largely resolved over the next 3 weeks, although persistent keratopathy. Intraocular pressures on subsequent outpatient ectasia and thinning were noted with a CCT of 518. He continues to follow-up ranged from 5 to 7 mm Hg OD and from 13 to 18 be followed on an outpatient basis 7 years later with 20/300 vision mm Hg OS. The subtle leak resolved by the next visit, and the and progressive thinning. hydrops showed signiﬁcant resolution within 2 weeks, with an eventual residual area of corneal thinning with a CCT of 490 mm (Fig. 1B). Topography was obtained (Fig. 1C). The patient subsequently returned months later with another episode of hydrops in the same eye, with a Descemet break seen at a different location. He was found to be slowly Seidel positive at the area of greatest thinning (Fig. 1D), and he underwent penetrating keratoplasty OD shortly thereafter. The host corneal tissue was sent for pathologic analysis (Fig. 2).

Case 2 A 25-year-old African American man was referred to the UIC Cornea Service for corneal thinning in the left eye. He had been followed for juvenile idiopathic arthritis (JIA) and chronic iridocyclitis by the UIC Uveitis Service for the previous 18 years. His right eye became phthisical after 2 unsuccessful retinal detachment repairs. He had undergone cataract extraction without intraocular lens placement, silicone oil placement, and removal with the last procedure occurring 11 years ago, with subsequent intraocular pressures between 0 to 1 mm Hg in the left eye. He had been treated with chronic topical corticosteroids and anterior sub-Tenon FIGURE 2. Pathology specimen from case 1 (original magni- corticosteroid injections. ﬁcation ·40). This slide shows severe thinning and a desce- On examination, visual acuity was no light perception OD and metocele centrally, with surrounding stromal edema on both 20/400 OS. Intraocular pressure was not measured OD and was 6 sides. The basal epithelium on the left side of the image shows mm Hg OS. CCT measurement was initially deferred. Anterior a hydropic change. The descemetocele corresponds to the segment examination revealed phthisis OD and paracentral corneal area of severe thinning observed clinically, which was rela- edema OS with an arcuate area of severe thinning extending from tively distant from the Descemet tear.

5 mm Hg over the previous year, having been previously in the low teens. Aphakic contact lens fittings, topography, and manifest refraction with the UIC Contact Lens Service before the development of hypotony were not suggestive of corneal irregularity. On presentation, her visual acuity measured hand motions OD and 20/25 OS. She was noted to have an arcuate area of corneal thinning inferotemporally OD with a surrounding area of corneal edema, a corresponding break in Descemet membrane and a slowly Seidel positive leak (Fig. 4A). Topography of the left eye showed central thinning but normal anterior and posterior curvatures. CCT was 566 mm OD and 514 mm OS. A bandage contact lens was placed with resolution of the leak by day 3 and the hydrops by day 9 after onset (Fig. 4B). Vision in the right eye improved to 20/25 with aphakic correction. On follow-up visits for rigid gas-permeable lens fitting, she was noted to have progressive corneal steepening OD. She eventually underwent a penetrating keratoplasty in the right eye with a contact lens–corrected distance visual acuity of 20/100 and intraocular pressure of 7 mm Hg on follow-up. Over the past 11 FIGURE 3. External photograph of the left eye from case 2. years, her left eye has developed a similar pattern of severe arcuate Examination revealed corneal thinning in an arcuate configu- thinning, without hydrops, in the setting of chronic uveitis and ration superiorly and mild hydrops paracentrally. hypotony treated with local corticosteroids without a fluocinolone implant (Figs. 4C, D). This eye is under consideration for corneal Case 3 transplantation with a last corrected distance visual acuity of 20/200 and an intraocular pressure of 7.5 mm Hg. A 38-year-old African American woman was referred to the UIC Cornea Service in 2003 for acute pain and corneal edema occurring on the same day. She had been followed for chronic DISCUSSION idiopathic iridocyclitis by the UIC Uveitis Service since 2000, undergoing cataract extraction OU with resultant aphakia in 2001 This series of 4 eyes of 3 patients demonstrates a unique and a fluocinolone implant OD in 2002. Despite her corticosteroid clinical entity in which corneal ectasia developed in the implant, her intraocular pressures in the right eye remained under setting of ocular hypotony, resulting in a significant reduction

FIGURE 4. A, External photograph of the right eye from case 3 at presentation demonstrating an area of hydrops inferotemporally in an arcuate configuration. The patient was noted to be Seidel positive. B, External photograph of the same eye 9 days later shows significant resolution of hydrops. C, Axial topography (Keratron; Optikon 2000) demonstrating corneal irregularity of the left eye in 2005. There is inferotemporal steepening in an arcuate configuration D, External photograph of the left eye at follow- up in 2015. There is an arcuate area of thinning inferotemporally, along with ectasia as demonstrated by the slit beam. This eye has shown progressive ectasia in the setting of chronic hypotony that has been followed for more than a decade.

in vision and ocular integrity. All 3 patients were diagnosed patients did have significant chronic topical corticosteroid with chronic iridocyclitis, which was in one case associated exposure, which has been shown in experimental models to with JIA. Three eyes developed corneal hydrops, which in modulate corneal rigidity.16,17 All affected eyes also had each patient was the initial sign of keratectasia. The fourth eye a history of chronic hypotony, which affects roughly 4.5% of (case 3) has developed an identical clinical picture while patients with JIA.18 Other factors were cataract extraction (3 under close observation over more than a decade, strongly eyes aphakic), previous vitrectomy with fluocinolone im- supporting the possible association of hypotony with this plants (2 eyes), and previous vitrectomy with silicone oil entity. As the number of patients achieving stable hypotony placement and removal (1 eye). Cases 1 and 2 presented increases (eg, those with uveitis or surgically treated glau- acutely with corneal hydrops, making it possible that coma), it is important to recognize that low intraocular keratoconus preceded ocular hypotony, whereas both eyes pressures may be associated with an increased risk of corneal of case 3 were observed for years for aphakic contact lens thinning as a cause of unexplained visual loss, hydrops, and fittings only developing ectasia 1 to 3 years after the onset of even acute corneal perforation. It is also important to consider hypotony in the right and left eyes, respectively. the potential pathophysiology of this entity as it may apply to On clinical examination, all of our patients had easily other corneal ectasias. deformable globes when external digital pressure was applied. The clinical presentation and disease course of these In some patients, when their intraocular pressures were patients was certainly unique. The corneal thinning was especially low, the upper eyelid could be observed linearly uncharacteristic of keratoconus or pellucid marginal degen- deforming the globe with each blink. We hypothesize that this eration in that it occurred in a thin arcuate pattern, either repeated mechanical stress in the setting of poor ocular rigidity superiorly or inferiorly, resembling a “corneal crease” and contributed to a narrow area of corneal flexion and consequent eventually involving greater than 6 clock hours of the characteristic thinning (ie, a corneal crease) common to all 3 paracentral and/or peripheral cornea. Although thin, the patients, similar to bending a wire repeatedly in the same central cornea was comparatively less affected, perhaps location until a critical threshold of weakness is reached. It is contributing to their referral only after the development of unclear whether aphakia or vitrectomy would further compro- hydrops. Clinical signs of corneal ulceration, neovasculariza- mise ocular rigidity, with the few studies on the corneal tion, or inflammation were absent throughout their follow-up. hysteresis of postcataract surgery and vitrectomized eyes Furthermore, 2 of the patients presented with acute exhibiting mixed results.19–21 Although the pattern of corneal perforation associated with a Descemet tear distant from the ectasia was unique in our series, the effect of repetitive corneal anterior communication. This was confirmed by pathology in trauma in this extreme setting of corneal deformability could case 1, which demonstrated an area of severe thinning support the contribution of mechanical factors in the patho- corresponding to the area of thinning observed clinically, genesis of more traditional forms of corneal ectasia. and a relatively robust stromal thickness on either side with an Previous studies have demonstrated changes in corneal intact Descemet membrane in this region. Although intra- curvature, albeit temporary, with external forces. The influ- stromal clefts are seen in corneal hydrops, perforations are ence of eyelid pressure on corneal curvature has been uncommon, suggesting that an area of stromal compromise demonstrated in patients performing visual tasks with the may have existed before the break in Descemet membrane. greatest change occurring near the eyelid margin.6–9 It has The resolution of the hydrops, even with perforation, was also been shown that there is a decrease in with-the-rule astigma- distinctly more rapid than in keratoconus, occurring initially tism after medically indicated botulinum toxin A injection in all 3 eyes in less than 3 weeks without surgical (eg, for blepharospasm) and that this effect reverses as the intervention.14 effect of the medication wears off.10 Digital pressure in the Corneal ectasia is an uncommon but not rare disorder, form of eye rubbing also induces temporary changes in with prevalence rates of keratoconus ranging from 8.8 to 54.4 corneal topography.11 per 100,000.15 For keratoconus, the pathogenesis remains Although hypotony has not previously been associated unclear with sometimes conflicting evidence for genetic, with corneal ectasia, it has been reported to reversibly affect inflammatory, and mechanical factors.3–5 Studies have sug- corneal astigmatism. In a series of 2 patients, reversal of gested an association with inflammatory mediators, although hypotony led to a significant reduction of several diopters of it is unknown whether these are causative or consequential. corneal astigmatism.12 The authors postulated that hypoto- Numerous genetic loci have been described but their consis- nous eyes are more susceptible to changes in corneal tent role has not yet been determined. The association of curvature induced by mechanical pressure exerted by the keratoconus with a history of mechanical eye rubbing has eyelids. This is consistent with the concept of corneal been well documented, but its role in pathophysiology is hysteresis, in which eyes with lower intraocular pressure somewhat unclear. have less corneal rigidity.13 Together, these studies suggest None of our patients had the common corneal risk that corneal curvature can be altered by external pressure factors for ectasia including a known personal or family (from blinking, eye movements, and eye rubbing) and that history of keratoconus or pellucid marginal degeneration, these changes may be amplified in the setting of hypotony. atopy, eye rubbing, or previous refractive surgery. Chronic Interestingly, 1 report showed that reduction of intraocular iridocyclitis alone, to our knowledge, has not been associated pressure within the normal range reversed postrefractive with corneal ectasia, and none of our patients had any signs of surgery ectasia, which the authors postulated was due to active or previous corneal inflammation or ulceration. All a reduction of internal pressure on the cornea.22

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