we present the case of a 17-year - old female diagnosed with chronic herpes simplex virus ( hsv ) keratitis   on her left eye , affected at a very young age ( 20 months of age ) .
informed consent was obtained from the subject at the time of the first clinical visit .
this study adhered to the tenets of the declaration of helsinki and was approved by the ethics committee of our institution .
we have treated her aggressively with topical corticosteroid therapy and oral antibiotics over the last year .
we decided to assess the cornea irregularity caused by the inflammatory stromal response since this case was stable over the last 6 months .
 80. the affected left eye had uncorrected distance visual acuity 20/40 , manifest refraction + 2.00 7.50  170 , and best - spectacle corrected distance visual acuity with this prescription of 20/32 .
we have recently reported   the clinical results of a novel topography clinical system based on anterior corneal surface imaging by reflection of color - coded light - emitting diode ( led ) spots array .
topography systems with color - coded point - source reflection forward ray - tracing have been proposed   as alternatives to placido ring imaging , enabling , among other , the proper imaging of radial , rather than only contour topographic changes .
the vu topographer ( vrije universiteit medical center , amsterdam , the netherlands )   introduced a color - coded square chess - pattern array projected on the cornea instead of the placido rings .
the surface reconstruction algorithm employed data from the pattern crossing points to eliminate source - image mismatch . in principle , this color - coded topographer was found to be efficient in reconstructing the nonrotationally symmetric anterior corneal surface .
the cassini ( i - optics bv , the hague , the netherlands ) topography system is a novel topographer employing multispot ( up to 700 ) , multicolor ( red , yellow and green ) led tear film - reflection - imaging , following the steps of the vu topographer .
the difference is that instead of a limited number of color - coded squares , there are over 600 led spots on the radial and contour arrangement imaged on the cornea .
image processing algorithm locates feature points in the reflection image and accounts for smearing and deformation in irregular corneas .
every three spots identified by the software are processed by ray tracing , and the relevant 
this process is theoretically unbiased by media opacity and differs from the center to periphery dependence of data processing that occurs with placido - disk topographers .
the system has been recently introduced   and has received us food and drug administration ( fda ) approval for clinical use in corneal topography .
due to the novelty , clinical validation of such systems and their clinical implications has yet to be investigated .
the scope of this paper is to examine the clinical feasibility of a newly introduced point - source color - coded corneal topography in a case of keratitis imaging .
placido topography was provided by the alcon / wavelight allegro topolyzer ( alcon surgical , fort worth , tex .
the topolyzer is a wide - cone corneal topographic placido system with 22 concentric rings for the detection of up to 22,000 elevation points .
scheimpflug topometry was provided by the wavelight oculyzer ii ( alcon surgical ) , a pentacam hr ( high - resolution ) camera providing corneal pachymetry and topometry maps .
anterior - segment optical coherence tomography ( as - oct ) was employed for cornea cross - section , corneal pachymetry , and epithelial thickness maps .
usa ) , running on analysis and report software version a6 ( 9,0,27 ) was employed for this purpose .
finally , the cassini ( running on software version 1.3 , updated december 2013 ) was employed to provide anterior surface imaging .
the system produces anterior elevation , tangential and axial curvature , and refractive power 3-dimensional maps covering the 7.5-mm diameter area .
the report provides keratometry data ( steep and flat simk , simulated astigmatism ) , and computes topographic and keratoconus indices .
1 presents an oct high - resolution meridian scan of the affected eye , and the corresponding scheimpflug imaging raw scan .
we observed the intracorneal scar , appearing as a stromal opacity associated with the residual stromal scarring , located in the near inferior nasal area .
2 presents a placido ring imaging and the axial curvature map obtained with the topolyzer .
it is evident that the system was unsuccessful to register proper information , as the axial curvature map was poorly calculated .
fig . 3 presents corneal pachymetry derived from scheimpflug imaging ( 9 mm diameter ) and the corresponding oct - derived ( 6 mm diameter ) corneal and epithelial thickness maps .
the imaging depicts successfully the corneal opacity , and produces a nearly complete axial curvature map . as it can be noticed in fig .
3a , the posterior surface is poorly identified at the lesion , as expected due to the corneal opacity .
thinnest pachymetry was reported by the scheimpflug data at 380 m , while by oct at 480 m .
4 presents comparatively data from the imaging on the affected eye indicating impressive agreement of the anterior surface elevation and curvature maps between the cassini topographer and the scheimpflug device .
scheimpflug imaging reports a bump ( about 50 d ) on the superior side of the map that is not present in the color led topography map .
this partial agreement may be attributed to incomplete imaging by either device over the specific area or to imaging interpolation difficulties over the scarred region .
one - year of follow - up has been recommended to validate the anterior - segment imaging findings .
ocular scatter and cornea densitometry measurements may further establish the scar morbidity on visual performance of the patient .
hsv keratitis and its sequelae is the most frequent cause of corneal blindness in the united states and the most common source of infectious blindness in the western world [ 11 , 12 ] .
subsequent corneal scarring , which may have severe impact on the anterior surface and tear film regularity , as well as stromal density , as indicated by the oct imaging , renders placido and scheimpflug imaging in this case challenging . in this work
, we examined the clinical feasibility of a newly introduced multicolored - spot reflection corneal topographer in a case of hsv keratitis in comparison to established methods of clinical imaging , namely oct , placido and scheimpflug imaging .
thinnest cornea pachymetry with scheimpflug imaging ( measured 380 m ) was in large disparity with the oct thinnest pachymetry ( 480 m ) .
we believe that this is a disadvantage of the scheimpflug imaging principle , which assumes clear cornea interpolation of the posterior surface .
when comparing the cassini to the placido system , this case suggests that the increased sensitivity , which includes both radial and contour differences based on spot imaging , enabled proper imaging of this highly irregular cornea . particularly considering the extent of the abnormality present in this case , and the fact that significant distortion was also located at the center , the placido device was not successful in imaging this case .
the scheimpflug imaging was successful in imaging the anterior surface , but not the posterior .
the clinical relevance lies in cases where cornea curvature accuracy is needed , such as iol power calculations .
this case report , based on led color reflection topography imaging in comparison to scheimpflug and placido imaging , verifies the clinical applicability of the new technology in the imaging of disturbed and highly asymmetric cornea .
the facility and comparable results offered by the cassini , in comparison to established placido and scheimpflug imaging , as well as the possibility of increased predictability that may be offered by the novel corneal imaging in highly irregular corneas , may hold promise for wider clinical application , such as screening of corneas either highly asymmetric and/or with highly coinciding opacities . the potential higher specificity in the central cornea that seems to be unaffected by cornea opacities may offer a differential advantage in relation to other contemporary cornea imaging devices .
additionally , concerning highly distorted corneas , the every-3-spots - ray tracing calculation used with the cassini may offer higher predictability in correlation to placido - derived topography were a central irregularity may bias axially the relevant section of the map .
 this case report aims to evaluate safety , efficacy and feasibility of anterior surface imaging by a novel point - source reflection topographer , in comparison to four other corneal imaging modalities . 
 a 17-year - old female patient , clinically diagnosed with chronic herpetic keratitis in her left eye was imaged by a novel multicolored - spot reflection topography system . 
 we comparatively investigated elevation and curvature maps between the novel topographer and established placido disk topography and scheimpflug tomography systems . 
 pachymetry maps were compared between the scheimpflug system and anterior - segment optical coherence tomography system . 
 the placido system failed to properly register the abnormal anterior surface due to incomplete mire registration , while the scheimpflug topometry device imaged the anterior surface properly , but not the posterior ( due to media opacity ) , and thus pachymetry was highly irregular and erroneous in this case . 
 imaging of corneas infected with herpes simplex virus keratitis has been rare ; we have not identified any such documentation in the peer review literature in the last 10 years 
 . this novel multicolored - spot reflection topography imaging may offer successful corneal imaging in cases where established clinical topography systems may fail to produce accurate reconstruction of the corneal shape . 
 this is an important case demonstrating exceptional clinical feasibility in such rare cases offered by a newly introduced technology in ophthalmic imaging . 
Case Presentation
Investigations
Differential Diagnosis
Discussion
Conclusions