CLINICAL COMMUNICATION

In vivo confocal microscopy of climatic droplet keratopathy

Clin Exp Optom 2013; 96: 430–432 DOI:10.1111/cxo.12030

Riyaz Bhikoo* MBChBRachael L Niederer* PhD MBChBRichard Hart† FRANZCOTrevor Sherwin* PhDCharles NJ McGhee* PhD FRCS FRANZCO* Department of Ophthalmology, Faculty of Medicaland Health Sciences, The University of Auckland,Auckland, New Zealand† Department of Ophthalmology, Greenlane ClinicalCentre, Auckland, New ZealandE-mail: riyazbhikoo@gmail.com

We describe the corneal microstructural changes in a patient with spheroidal degenerationusing in vivo confocal microscopy. Multiple hypo- and hyper-reflective spherical lesions wereobserved in the anterior corneal stroma and Bowman’s layer ranging from 45 to 220 mm insize. The corneal epithelium, posterior stroma and endothelium were otherwise unaffected.In vivo confocal microscopy demonstrates good correlation with excised histological samplesin climatic droplet keratopathy. It provides a non-invasive technique to examine the livingcornea for degenerative disease and acts as a bridge between clinical and laboratoryobservations.

Submitted: 26 February 2012Revised: 1 September 2012Accepted for publication: 11 September2012

Key words: climatic droplet keratopathy, in vivo confocal microscopy, spheroidal degeneration

Climatic droplet keratopathy (CDK) is adegenerative disease characterised by theappearance of golden spheroid-like depo-sits in the superficial corneal stroma. Expo-sure to ultraviolet (UV) light is the mainaetiological factor responsible for the devel-opment of CDK; however, the risk is com-pounded in patients with a history ofrecurrent ocular inflammation or trauma.1

Although often mild, CDK can be visuallysignificant in advanced disease, yet ourcurrent understanding of the pathologicalprocess has come from a limited number ofhistological studies.2

In vivo confocal microscopy enableshigh magnification examination of the liv-ing human cornea in physiological condi-tions, providing a bridge between clinicaland laboratory observations.3 It has gainedclinical applications principally in the diag-nosis of corneal infection, corneal surgery,corneal dystrophies and in the elucidation ofendothelial disorders.3,4

We report the use of in vivo confo-cal microscopy to assess the microstruc-tural changes seen in CDK.

CASE REPORT

A 60-year-old Caucasian male suffered ablunt injury to his left eye, while playingrugby 20 years earlier, resulting in verticaltransection of the central superior tarsalplate. Consequently, there was non-unionhealing of the injury, which resulted in adegree of upper lid entropion and anirregular palpebral conjunctival surface.The patient reported a foreign body sensa-tion with irritation and constant rubbingof the left eye; however, his vision wasunaffected.

He had a past medical history of invasivesquamous cell carcinoma on his righthand which had been excised and on exami-nation, diffuse dermatological changesconsistent with chronic UV exposure wereobserved.

His visual acuity was 6/5-2 R and 6/5-1 L.Slitlamp examination revealed left upper

lid entropion and a non-union healing ofthe tarsal plate (Figure 1). The left corneashowed golden-yellow circular deposits(droplets) situated within the interpalpeb-

ral strip at the level of the anterior stromaand Bowman’s layer (Figure 2). There wasno corneal neovascularisation. The rightcornea was clinically normal.

In vivo confocal microscopyAfter detailed explanation and informedconsent, using a laser scanning in vivoconfocal microscopy (Heidelberg RetinaTomograph II Rostock Corneal Module;Heidelberg Engineering, Heidelberg,Germany) of the central cornea was per-formed. This microscope uses a 670 nm redwavelength diode laser source. A 60 timesobjective water immersion lens with anumerical aperture of 0.9 and a workingdistance, relative to the applanating cap,of 0.0 to 3.0 mm was employed. The sub-sequent images are 400 by 400 mm withtransverse resolution and optical sectionthickness of 2.0 and 4.0 mm, respectively.The eye was anaesthetised with one drop of0.4 per cent benoxinate hydrochloride. Vis-cotears was used as a coupling agent betweenthe applanating lens and the cornea.

C L I N I C A L A N D E X P E R I M E N T A L

OPTOMETRY

Clinical and Experimental Optometry 96.4 July 2013 © 2013 The Authors

430 Clinical and Experimental Optometry © 2013 Optometrists Association Australia

The patient was asked to fixate on a distanttarget and the full thickness of the centralcornea was observed. The total durationof in vivo confocal examination was twominutes per eye. No visual symptoms orcorneal complications were experienced as aresult of the examination.

In vivo confocal microscopy examina-tion of the central cornea showed multi-ple hyper- and hypo-reflective well-circum-scribed spherical changes at the level of theanterior corneal stroma and Bowman’s layer(Figure 3). These corneal alterations rangedin size from 45 to 220 mm in width and cor-responded to the spheroidal degenerativedeposits as seen clinically. Radial lines wereobserved radiating from the central lesion(Figure 3B). Most likely this representsalteration of the corneal architecture dueto the spheroidal degenerative deposit.

The basal epithelium, posterior stroma andendothelium were normal. No activatedkeratocytes were observed.

The patient underwent entropion repairwith wedge excision and direct closure ofthe upper lid. Despite the central loca-tion of the spheroidal deposits, the patientwas largely asymptomatic with excellentvisual acuity. He was discharged back tohis general medical practitioner, who wasadvised to refer him to an anterior segmentspecialist should the deposits become visu-ally significant.

DISCUSSION

Previous studies of CDK degeneration haveexamined the histological characteristics ofthe disease from human corneal specimensobtained following penetrating keratoplasty

or at autopsy, many eyes having associatedchronic angle glaucoma and/or diabeticretinopathy.5 Confocal microscopy enablesexamination of eyes with mild disease thatwould not normally require penetratingkeratoplasty and thus would not normally beavailable for histological analysis.

Climatic droplet keratopathy or spheroi-dal degeneration can be classified intoprimary or secondary types. Both advancingage and UV light exposure are thought tobe related to the development of primaryCDK, a bilateral condition, characterisedby well circumscribed translucent goldendeposits commonly seen at the limbus (3and 9 o’clock positions) extending to theconjunctiva.1 Secondary CDK is observed inpatients with a history of UV exposure andocular injury or inflammation. Much likethe case we have presented, the findings are

Figure 1. Slitlamp examination demonstrated malunion of the superior tarsal plate (A and B)

Figure 2. Multiple golden, well-circumscribed deposits in the superficial cornea (A and B)

In vivo confocal microscopy of climatic droplet keratopathy Bhikoo, Niederer, Hart, Sherwin and McGhee

© 2013 The Authors Clinical and Experimental Optometry 96.4 July 2013

Clinical and Experimental Optometry © 2013 Optometrists Association Australia 431

unilateral with deposits aggregating in areasof repeated microtrauma, which in this casewas a consequence of an irregular tarsal con-junctival surface and upper lid entropion.

The distribution of corneal involvementidentified with confocal microscopic exami-nation was similar to previously reportedhistological specimens, with changes involv-ing Bowman’s layer and the superficialcorneal stroma, sparing the corneal epithe-lium, Desçemet’s membrane and endothe-lium. Histological findings show multipleglobules of variable size, which accumul-ate in the epithelial basement membrane,Bowman’s layer and/or anterior cornealstroma.5–7

In the majority of cases, the lesions areasymptomatic and treatment is directedtoward reducing UV exposure and manag-ing other underlying ocular diseases, for

example, entropion. Superficial keratec-tomy or excimer laser excision is usuallyreserved for patients with visually incapaci-tating disease.1

The use of in vivo confocal microscopy hasexpanded our understanding of the livingcornea at the microstructural level and thecurrent study demonstrates good correla-tion with excised histological samples inCDK. This evolving, non-invasive imagingtechnique provides clinicians with a usefultool for accurate assessment of the livinghuman cornea in health and disease.

REFERENCES1. American Academy of Ophthalmology. External

disease and cornea. In: Basic and Clinical ScienceCourse, Section 8. 2004–2005.

2. Johnson GJ, Overall M. Histology of spheroidaldegeneration of the cornea in Labrador. Br J Oph-thalmol 1978; 62: 53–61.

3. Niederer RL, McGhee CNJ. Clinical in vivo confocalmicroscopy of the cornea in health and disease.Progress Ret Eye Res 2010; 29: 30–58.

4. Vincent AL, Patel DV, McGhee CNJ. Inheritedcorneal disease: the evolving molecular, genetic andimaging revolution. Clin Experiment Ophthalmol2005; 33: 303–316.

5. Klintworth GK. Chronic actinic keratopathy—a condition associated with conjunctival elastosis(pingueculae) and typified by characteristic extra-cellular concretions. Am J Pathol 1972; 67: 327–348.

6. Johnson GJ, Ghosh M. Labrador keratopathy: clini-cal and pathological findings. Can J Ophthalmol 1975;10: 119–135.

7. Magovern M, Wright JD Jr, Mohammed A. Spheroi-dal degeneration of the cornea: a clinicopathologiccase report Cornea 2004; 23: 84–88.

Figure 3. In vivo confocal microscopic appearance of climatic droplet keratopathy.All images 400 ¥ 400 mm. (A) Normal appearance of the basal epithelium. (B) Largehypo-reflective and smaller hyper-reflective lesions at Bowman’s layer. (C and D) Lesionsin anterior corneal stroma.

In vivo confocal microscopy of climatic droplet keratopathy Bhikoo, Niederer, Hart, Sherwin and McGhee

Clinical and Experimental Optometry 96.4 July 2013 © 2013 The Authors

432 Clinical and Experimental Optometry © 2013 Optometrists Association Australia