Anterior Segment Optical Coherence Tomography Findings of Acute Hydrops in a Patient with Keratoconus

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■ case report ■

Anterior Segment Optical stroma and results in intrastromal edema and clefts. Patients often present with spontaneous onset of pain, Coherence Tomography photophobia, and blurred vision; eye rubbing and al- Findings of Acute Hydrops in a lergy may be risk factors. This condition can also be seen Patient With Keratoconus in patients with pellucid marginal degeneration.2 We describe a case of acute hydrops associated with keratoconus in which we investigated the corneal mor- Beril R. Kucumen, MD phology by anterior segment optical coherence tomog- Nursal Melda Yenerel, MD raphy (AS-OCT). Ebru Gorgun, MD Umut Asli Dinc, MD CASE REPORT A 25-year-old man was referred to our University Eye ABSTRACT Clinic with complaints of spontaneous sudden onset of The authors describe the anterior segment optical coher- pain, decrease of vision, epiphora, and photophobia of the ence tomography (AS-OCT) findings of a 25-year-old left eye. He had been diagnosed as having keratoconus patient with acute hydrops associated with keratoconus. 18 months prior. The slit-lamp findings from September The patient presented with decreased visual acuity, pain, 2007 revealed Vogt stria, Munson’s sign, and apical scar and redness in the left eye. The symptoms, clinical pre- of the left cornea; the patient was contact lens intolerant sentation, and topographical findings of the right eye and scheduled for keratoplasty at that time. The oph- confirmed this condition to be acute corneal hydrops. thalmological examination from January 2009 included The patient was closely followed up with hyper-osmotic autorefraction, uncorrected visual acuity (UCVA), best (NaCl 5%) and nonsteroidal anti-inflammatory (ketoro- spectacle-corrected visual acuity, intraocular pressure, slit- lac tromethamine 0.5%) topical treatment. At the initial lamp examination, and dilated fundus examination. The examination and during follow-up, the evaluation of the follow-up examinations were performed monthly. The anterior segment was performed using optical coherence best spectacle-corrected visual acuity of the right eye was tomography. Changes in the stroma and Descemet’s mem- 20/30, whereas UCVA of the left eye was hand motions brane during the healing process of acute hydrops could and could not be raised by correction. be demonstrated by high-resolution AS-OCT. [Ophthal- Slit-lamp examination of the left eye revealed a cen- mic Surg Lasers Imaging 2010;41:S114-S116.] tral edematous corneal hydrops (Fig. 1). One month later, the UCVA increased to counting fingers from 15 INTRODUCTION cm; the edematous zone had decreased in diameter and Acute hydrops is a rare complication of keratoconus the subjective complaints of the patient regarding pain that is caused by a rupture in Descemet’s membrane.1 had decreased. The patient did not come to his regular This rupture causes endothelial dysfunction and/or ab- examination in the following month for personal rea- sence that allows aqueous humor to enter the corneal sons. Three months later, the UCVA of the left eye had

From the Department of Ophthalmology, Yeditepe University Eye Hospital, Istanbul, Turkey. Originally submitted May 12, 2009. Accepted for publication March 19, 2010. The authors have no financial or proprietary interest in the materials presented herein. Address correspondence to Beril R. Kucumen, MD, Yeditepe University Eye Hospital, Department of Ophthalmology, Gazi Umur Pasa Sok.25, Balmumcu, Besiktas, Istanbul, Turkey. E-mail: [email protected] doi: 10.3928/15428877-20101031-12

Figure 1. Appearance of acute hydrops in keratoconus by slit- lamp examination at presentation. increased to counting fingers from 30 cm and the hydrops had become smaller in diameter. A full ophthal- mological examination, photodocumentation of the anterior segment, and anterior segment optical coherence tomography (AS-OCT) were performed at each visit. Intrastromal confluent pseudocysts could be demonstrated in high-resolution cornea images by the Visante OCT (Carl Zeiss Meditec, Inc., Dublin, CA) (Fig. 2).

DISCUSSION AS-OCT is a new imaging technique that allows cross-sectional, clear visualization and accurate in-depth imaging of the anterior segment, enabling qualitative and quantitative analysis of the corneal layers at different lev- els, especially when the cornea is opaque.3 High-resolution corneal images can be recorded in any desired meridian by Figure 2. Anterior segment optical coherence tomography (AS-OCT) Visante OCT, enabling us to evaluate the posterior cor- images of acute hydrops in chronological order. The findings were simi- nea that cannot be otherwise thoroughly visualized. This lar in four quadrants; therefore, only horizontal images have been presented for comparison. (A) High-resolution corneal image on horizontal modality improved our evaluation of the posterior corneal meridian at presentation. A large defect in the Descemet’s membrane morphology that was not visible by the slit-lamp examina- is noticeable. There are numerous stromal pseudocysts with different tion. Imaging of Descemet’s membrane detachment using sizes having contact with each other in a petalloid pattern. White arrow AS-OCT has been reported previously.4 indicates the thinnest part of the cornea—the epitheliocele. The diam- In our case, AS-OCT demonstrated the detailed eter of the edematous zone in the cornea was measured as 6.03 mm; structure of intrastromal clefts in high-resolution cor- the thickness was 1.61 mm. (B) AS-OCT image of the eye 1 month later. The pseudocysts in the anterior stroma tend to coalesce and form neal images. During follow-up, it was especially valuable a big conical pseudocyst posteriorly. The epitheliocele has become in evaluating the thinnest part of the cornea that carries thicker; the Descemet’s membrane shows a double contour at one perforation risk. This portion of the cornea was previ- end. (C) AS-OCT image of the eye 2 months later. One big pseudo- ously defined as descemetocele.5 We measured the thick- cyst has formed between the Descemet’s membrane and stroma. The ness of this vulnerable location of the cornea that con- free edges of the Descemet’s membrane are rolled inward and appear thicker. (D) AS-OCT image of the eye 4 months later. The epitheliocele sisted of intact epithelium and a narrow band of anterior has disappeared. The corneal stroma appears considerably normal stroma as 150 microns by the calipers of Visante OCT with no clefts between the lamellae. The pseudocyst is narrower with (Fig. 1A). We would suggest the term epitheliocele in- a smooth lining. The diameter of the edematous zone in the cornea stead of descemetocele for the description of this lesion decreased to 5.23 mm and the thickness reduced to 0.84 mm.

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highlighted the biomechanism of acute hydrops. We were able to demonstrate the central rupture in the Descemet’s membrane and could follow up its natural healing process. The central defect was polygonal rather than linear and became smaller, similar to the healing of epithelial defects of the cornea but more slowly (Figs. 2 and 3). This is probably due to the slow formation and repair of the Descemet’s membrane by endothelial cells. The defect in Descemet’s membrane gets smaller at the same time the edematous zone in the anterior cornea gets smaller in diameter. But there may be variation in the area of the cornea actually scanned due to the centralization of the affected area; therefore, we may not be able to scan the same cross-section at every examination. Corneal perforation is a rare complication of acute hydrops that has been reported previously.5-7 Aldave et al. reported 3 cases with spontaneous perforation in acute hydrops, but they also mentioned that this condition is typically self-limited in most of the cases and resolves over a period of 6 to 10 weeks as endothelial cells migrate over the exposed stroma forming a thin portion of Descemet’s membrane.5 In our opinion, high-resolution AS-OCT may be helpful in predicting a possible spontaneous perforation that fortunately did not occur in this patient. This imaging technique is supportive in close follow-up of patients with imminent perforation. High-resolution AS-OCT is efficient in determin- ing the detailed structure of corneal changes and biomechanism causing acute hydrops in keratoconus.

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