Journal of Pediatric Ophthalmology and Strabismus

Short Subjects 

Unilateral Posterior Polymorphous Corneal Dystrophy Associated With Ipsilateral Anisometropic Amblyopia

Mohammed Al-Amry, MD; Arif O. Khan, MD

Abstract

Posterior polymorphous corneal dystrophy is typically considered asymptomatic unless visual opacity develops. However, some have suggested that asymmetric disease without visual opacity might be associated with asymmetric refractive error, which would have the potential to be the cause of amblyopia in young children. In support of this concept, a case of unilateral posterior polymorphous dystrophy with ipsilateral anisometropic amblyopia is reported. [J Pediatr Ophthalmol Strabismus 2013;50:e55–e57.]

From the Divisions of Anterior Segment (MA) and Pediatric Ophthalmology (AOK), King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia.

The authors have no financial or proprietary interest in the materials presented herein.

Correspondence: Arif O. Khan, MD, Division of Pediatric Ophthalmology, King Khaled Eye Specialist Hospital, P.O. Box 7191, Riyadh 11462, Saudi Arabia. E-mail: arif.khan@mssm.edu

Received: March 23, 2013
Accepted: October 10, 2013
Posted Online: October 29, 2013

Abstract

Posterior polymorphous corneal dystrophy is typically considered asymptomatic unless visual opacity develops. However, some have suggested that asymmetric disease without visual opacity might be associated with asymmetric refractive error, which would have the potential to be the cause of amblyopia in young children. In support of this concept, a case of unilateral posterior polymorphous dystrophy with ipsilateral anisometropic amblyopia is reported. [J Pediatr Ophthalmol Strabismus 2013;50:e55–e57.]

From the Divisions of Anterior Segment (MA) and Pediatric Ophthalmology (AOK), King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia.

The authors have no financial or proprietary interest in the materials presented herein.

Correspondence: Arif O. Khan, MD, Division of Pediatric Ophthalmology, King Khaled Eye Specialist Hospital, P.O. Box 7191, Riyadh 11462, Saudi Arabia. E-mail: arif.khan@mssm.edu

Received: March 23, 2013
Accepted: October 10, 2013
Posted Online: October 29, 2013

Introduction

Posterior polymorphous corneal dystrophy is characterized by round and/or placoid lesions at the level of Descemet’s membrane with both polymorphism and polymegathism of the endothelium. Although childhood onset has been documented, there are few reports that describe affected children. Most authors consider the condition to be asymptomatic unless significant opacity develops; however, anisometropic amblyopia of the more affected eye has been reported in a few children with asymmetric disease. In support of this association, we describe a case of unilateral posterior polymorphous dystrophy with ipsilateral anisometropic amblyopia.

Institutional board approval was obtained for this case report.

Case Report

An 18-year-old man without a significant medical history had best-corrected and best pinhole visual acuity of 20/40 in the right eye and 20/20 in the left eye. When specifically questioned, there was no history of eye trauma or traumatic birth. There was no history for childhood eye examinations. There was no strabismus, microstrabismus, duction defect, or pupillary abnormality. Intraocular pressure was 12 mm Hg in both eyes by Goldmann applanation tonometry. Slit-lamp examination was significant in the right posterior cornea for central placoid changes with grey borders at the level of Descemet‘s membrane as is characteristic for posterior polymorphous corneal dystrophy.1 These lesions followed a vertical meridian and were not associated with clinically evident corneal thickening (Figure 1). The anterior segment was otherwise normal in both eyes. Keratometry (Pentacam HR; Oculus, Wetzlar, Germany) in diopters (D) was 44.1/47.5@090 in the right eye and 43.4/43.9@090 in the left eye. Central corneal thickness (Pentacam HR) was 567 μm in the right eye and 531 μm in the left eye. Specular microscopy (SP-3000P; Topcon, Tokyo, Japan) revealed an endothelial cell count (cell/mm2) of 700 in the right eye and 2,620 in the left eye with both polymorphism and polymegathism in the right but not the left eye (Figure 2). Cycloplegic refraction (cyclopentolate 1%) was +3.00-3.75 × 020 D in the right eye and +1.50-0.25 × 075 D in the left eye. Both eyes had a clear retinoscopy reflex. The posterior pole was normal in both eyes.

Slit-lamp examination of the right eye revealed deep rounded and placoid vesicular lesions at the level of Descemet membrane centrally and following a vertical axis. The left eye was normal.

Figure 1.

Slit-lamp examination of the right eye revealed deep rounded and placoid vesicular lesions at the level of Descemet membrane centrally and following a vertical axis. The left eye was normal.

(A) Specular microscopy of the right eye (original magnification ×150) revealed both polymorphism and polymegathism and an endothelial cell count of 700 per square millimeter. (B) Specular microscopy of the left eye (original magnification ×150) was normal, with an endothelial cell count of 2,620 per square millimeter.

Figure 2.

(A) Specular microscopy of the right eye (original magnification ×150) revealed both polymorphism and polymegathism and an endothelial cell count of 700 per square millimeter. (B) Specular microscopy of the left eye (original magnification ×150) was normal, with an endothelial cell count of 2,620 per square millimeter.

Discussion

This man had unilateral posterior polymorphous corneal dystrophy and ipsilateral anisometropic amblyopia related to corneal steepening in the meridian of the lesions. The left eye was unaffected and had no significant astigmatism. This case supports the concept that when the lesions of posterior polymorphous corneal dystrophy occur asymmetrically during childhood, there is a risk for visual loss from anisometropic amblyopia in the more affected eye.

The literature is limited regarding the subject of refractive amblyopia and posterior polymorphous cornea dystrophy. The only pediatric series of posterior polymorphous corneal dystrophy cases is of 4 consecutive children seen over a 3-year period by DeRespinis et al.2 The authors described all cases as asymmetric and with unilateral amblyopia related to greater corneal steepening in the more affected eye, which had its steepest meridian along the axis of the posterior polymorpous corneal dystrophy lesions when these lesions were well-defined rather than diffuse. Studies of patients with diffuse posterior polymorphous corneal dystrophy also support a corneal steepening effect from the lesions. In 14 diffuse cases (6 familial and 4 sporadic), patients were documented as having steep corneas without evidence for keratoconus (range: 46.47 to 59.86 D; mean: 52.21).3 This was also described for 5 diffuse cases from a single family.4 Less commonly, posterior polymorphous corneal dystrophy has also been reported in association with ectatic corneal disease such as keratoconus5–7 or keratoglobus8,9; however, because keratoconus is relatively common, the possibility exists that associations with keratoconus could be coincidental rather than causal.

In posterior polymorphous corneal dystrophy, corneal endothelial cells are replaced with cells that have epithelial properties (eg, tonofilaments, cytokeratin, and desmosomes).1,10 The condition is typically autosomal dominant and is genetically heterogeneous. At least three loci have been identified to date and potential candidate genes include COL8A2 and ZEB1.1 Clinically, at the level of the posterior stroma and Descemet’s membrane there are small aggregates of variously shaped vesicular lesions bordered by gray haze and there are gray placoid areas.1,10 The previous literature2–4 and the current case support that these findings are associated with non-ectatic corneal steepening but infrequently can be associated with corneal ectasia.7–9 Corneal haze from endothelial decompensation, when it occurs, is considered the major reason for visual loss in patients.1 However, even in the setting of clear corneas, children with posterior polymorphous corneal dystrophy are at risk for visual loss from refractive amblyopia, particularly those with asymmetric disease.

References

  1. Weiss JS, Møller HU, Lisch W, et al. The IC3D classification of the corneal dystrophies. Cornea. 2008;27(Suppl 2):S1–S83. doi:10.1097/ICO.0b013e31817780fb [CrossRef]
  2. DeRespinis PA, Norden RA, Rispoli LC. Posterior polymorphous dystrophy associated with astigmatism and amblyopia in children. J Refract Surg. 1996;12:709–714.
  3. Raber IM, Fintelmann R, Chhabra S, Ribeiro MP, Eagle RC Jr, Orlin SE. Posterior polymorphous dystrophy associated with nonkeratoconic steep corneal curvatures. Cornea. 2011;30:1120–1124. doi:10.1097/ICO.0b013e3182114452 [CrossRef]
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  6. Gasset AR, Zimmerman TJ. Posterior polymorphous dystrophy associated with keratoconus. Am J Ophthalmol. 1974;78:535–537.
  7. Mazzotta C, Baiocchi S, Caporossi O, et al. Confocal microscopy identification of keratoconus associated with posterior polymorphous corneal dystrophy. J Cataract Refract Surg. 2008;34:318–321. doi:10.1016/j.jcrs.2007.09.028 [CrossRef]
  8. Harissi-Dagher M, Dana MR, Jurkunas UV. Keratoglobus in association with posterior polymorphous dystrophy. Cornea. 2007;26:1288–1291. doi:10.1097/ICO.0b013e3181557692 [CrossRef]
  9. Patel SP, Sajnani MM, Pineda R. Posterior Polymorphous dystrophy and keratoglobus in a child. [published online ahead of print January 18, 2010]. J Pediatr Ophthalmol Strabismus. doi:10.3928/01913913-20100118-05 [CrossRef]
  10. Henriquez AS, Kenyon KR, Dohlman CH, et al. Morphologic characteristics of posterior polymorphous dystrophy. A study of nine corneas and review of the literature. Surv Ophthalmol. 1984;29:139–147. doi:10.1016/0039-6257(84)90171-1 [CrossRef]

10.3928/01913913-20131022-02

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