than just a camera. It is a diagnosticunit able to perform a host of dif-ferent measurements and analyseson the anterior segment of the eye.Using an automatic rotating camera,this innovation examines the ante-rior segment without ever touchingthe eye. The examination takesapproximately two seconds, timeenough to take about 50 picturesof the eye’s different anatomicallayers. There are several different

Five in One: An Innovation That Combines Several Diagnostic Strategies

Pentacam – The World’s First 3 D-Scheimpflug Camera

For any ophthalmologist whoconsiders buying a new device

for his private surgery or clinic, thecost-benefit ratio of such an in-vestment is of primary importance.Besides asking “What is this instrument able to do what otherscan’t” there is – for most doctors –the space issue: “Do I have roomfor another unit?”. It is a compactinstrument which combines severaldiagnostic strategies and promisesto fulfill the highest clinical, aswell as practical demands, and tofit in a very restrictive budget.

A symposium at the 17th Congressof Germany’s ophthalmic surgeonsin Nuremberg left the audience withthe impression that such a deviceis now available: the Pentacam,the world’s first three-dimensionalrotating Scheimpflug camera. Thismost intriguing innovation was pre-sented by experts like O. Kermani(Cologne), T. Neuhann (Munich)and O. Schneider (Wetzlar).The most striking feature of thePentacam is that it is much more

modules which analyze and inter-pret the tasks performed: Scheim-pflug picture, pachymetry, densito-metry, corneal topography, 3-Dchamber analysis and tomography.The data acquired is extremelyuseful for a number of ophthalmo-logical indications: refractive sur-gery, glaucoma, cataract and patho-logical conditions of the cornea likekeratoconus.

3-D analysis of the anteriorchamber helps to assess

the risk of glaucoma

Scheimpflug pictures can be takenas a series of single exposures fromdifferent angles as well as a 3-Dscan. The 3-D analysis presents thedifferent layers (anterior cornealsegment, the cornea’s posteriorlayer, iris and lens) in an easily recognizable way. In addition, thePentacam automatically measuresthe anterior chamber angle, cham-ber volume, chamber depth, cor-

Oculus Pentacam: Complete diagnosisof the anterior ocular segments

neal eccentricity, pupillary diame-ter, the cornea’s central radius andcorneal astigmatism at the same time. Pictures taken as a 3-D scan can be analyzed individually. According to O. Kermani, there isno significant difference betweenPentacam´s pachymetric results andthose of comparable (though ex-clusively pachymetric) instrumentsalready on the market. The sameapplies if the Pentacam’s kerato-metry is compared to that of devicesalready in use. An additional, andsometimes crucial benefit is mea-suring the anterior chamber depth.This gives the ophthalmologist arealistic idea of how seriously hispatient may be threatened byglaucoma. That knowledge can bedecisive in the preoperative plan-ning of corneal or lens surgerywhich might lead to a (further)shallowing of the chamber. T.Neuhann made it quite clear if thesurgeon has to deal with a chamberdepth of less than 2 millimeters, a

Pentacam

prophylactic YAG iridotomy shouldbe performed as an efficient wayto prevent angle closure.

Measuring the cornea’sthickness helps to evaluate

the “true” IOP

Glaucoma is in the literal crosshairsof another examination, measure-ment of the corneal thickness,which in some European countrieslike Germany has gained wide acceptance among the population.It is known that measuring theintraocular pressure (IOP) using aGoldmann is not the only test inglaucoma diagnostics. Intra-ocularpressure alone is only one of severalfactors that determine the existenceof glaucoma. This decision requiresa careful examination of the opticdisc. But the IOP measured by tonometry might not be exactlythe pressure that actually exists

inside the eye. The reason for thisconfusion, corneal thickness influ-ences the results of tonometry to a sometimes significant degree. If the patient’s cornea matchesexactly the statistically “normal”thickness of 550 µm, the IOP mea-sured is indeed the IOP that keepsthe eye in shape or, in glaucoma,threatens to damage the neuronalaxons. If the cornea is thinner,however, it is easier for Goldmann’sdevice to flatten its surface – theresult is an IOP reading which is unrealistically low. A resultmight give both the doctor and hisor her patient an undue sense ofsecurity – the threat of glaucomahides behind a false interpretationof Goldmann’s tonometry. The opposite can happen with a corneaof above-normal thickness: an “increased” IOP will be measuredwhich might lead to glaucomatherapy that – given the real, lowerIOP – comes too early or is too in-tense.

2 OPHTHALMO-CHIRURGIE SPECIAL EDITION NOVEMBER 2004

The cornea’s thickness is displayed for the whole surfacefrom limbus to limbus.

How Pentacam portrays a case of cataracta coronaria.

Pentacam

OPHTHALMO-CHIRURGIE SPECIAL EDITION NOVEMBER 2004 3

Using Pentacam’s pachymetricabilities puts these data into itsproper place again. If the ophthal-mologist knows the exact cornealthickness, calculating the real IOPwith some formulas is no problemat all. One of these formulas to determine the IOP, after havingmeasured corneal thickness, hasbeen developed by Professor LutzPillunat and his team at the Uni-versity Eye Hospital in Dresden.Using it on patients with an ex-tremely thin or an extremely thickcornea gives you an idea of howmisleading tonometry can become.A cornea that is only 450 µm thickmay have an IOP that is no lessthan 4,0 mm below the real thing– and in daily ophthalmologicalpractice, it makes a differencewhether a patient’s intra-ocularpressure is 20 mm Hg or 24 mmHg. A difference like this may be important to decide betweeninitiating treatment and a wait-and-see attitude. In dealing with athick cornea, the IOP has to be adjusted to a lower value. If, for example, the Pentacam detects acorneal thickness of 630 µm in apatient, according to the Dresdenformula 3,20 mm Hg has to be takenaway from the IOP measured withGoldmann’s tonometry.

Refractive surgery withoutknowing corneal thickness?

Never !

Pachymetry provided by Pentacamnot only plays a major role in glau-coma diagnostics, but also in thepre- and postoperative care of patients undergoing refractive sur-

gery T. Neuhann has pointed out –to know the exact location of thecornea’s thinnest spot. The Penta-cam’s keratometry gives the oph-thalmic surgeon an excellent over-view of the patient’s corneal topo-graphy and puts him or her in a position to operate even in areaswith a relatively thin stroma whilekeeping the necessary safety dis-tance. A postoperative assessmentof the flap is easily done and doesn’t bother the patient at all.The most important features of thisexamination are• automatic initiation of the mea-

surement,• a high reproducibility,• non-contact measuring,• less than two seconds required.Pentacam’s pachymetry providesdata from one limbus to the other.

Densitometry of the lens: a great tool for the long-term

control of cataracts

The cataract surgeon enjoys thesame benefits by relying on a pre-operative scan done with Pentacam.Pentacam’s densitometry of thehuman lens provides the ophthal-mologist with an analysis of thelens thickness and of structural alterations like radial opacitiesand early or advanced calcificationof the lens core. Densitometry comeswith advantages:• the evolution of a cataract can be

made visible even at an earlystage,

• it makes classification of the cata-ract easy,

• long-term controls of cataractsare possible and

• the extension of the cataract canbe measured.

Knowing the thickness of the lens ishelpful for the ophthalmic surgeonin deciding which type of IOL (intra ocular lens) to use for im-plantation. Furthermore, it hints –together with data on the anteriorchamber’s depth – to possible causesfor postoperative trouble. Hyper-opic eyes which are relativelyshort sometimes are a major causefor concern. In the event of anglereduction they tend to react with apostoperative IOP increase. Theyalso have a higher risk to developa macular degeneration followingphacoemulsification (or to worsenif macular degeneration alreadyexists at the time of cataract surgery). Assessing the anteriorchamber’s depth map is also pos-sible when using Artisan intra-ocular lenses, a task that, accor-ding to O. Kermani, both OrbScanII and IOL-Master can not perform.

Examination by Pentacam isboth efficient and fast...

Using Pentacam in your daily sur-gery is both easy and time-saving.According to O. Schneider the in-strument takes about 50 Scheim-pflug pictures within just two se-conds and can deliver up to 25.000true elevation points of topogra-phical information when measu-ring corneal topography. Due tothe high amount of data collectedthere usually is enough informationto come to a reasonable diagnosis.Even situations traditionally consi-dered artifacts like a narrow lidmargin or shadow zones can’t

Pentacam

OPHTHALMO-CHIRURGIE-Special Edition in collaboration with Oculus Optikgeräte GmbH, Münchholzhäuser Straße 29, 35582 Wetzlar, Germany

Editor: KIM – Kommunikation in der MedizinAuthor: Dr. med. Ronald D. GersteProject manager: Dr. med. S. Kaden

Dr. R. Kaden Verlag GmbH & Co. KGRingstraße 19b69115 HeidelbergGermany

4 OPHTHALMO-CHIRURGIE SPECIAL EDITION NOVEMBER 2004

prevent the Pentacam from produ-cing sufficient Scheimpflug pictu-res for clinical assessment

...and makes it easy for the patient to see his

doctor again

An examination is absolutelypain-free and is done within theshortest time span it’s most likely to become a favorite with the patients and thus strengthens thepatient-doctor relationship. Every-thing with Pentacam happens in a

non-contact way which reassureseven the most timid patient. It is also an educational tool because aprintout of his or her own clinicalpicture as captured by Pentacamcan be handed over to the patient.It is quite an impressive document.T. Neuhann compares its psycho-logical impact on the patient withthe sonographic picture of a babyin utero that usually is a source ofjoy to any expecting mother (andfather).The price for such an ex-tensive clinical examination cur-rently is about 75 Euro. The factthat operating Pentacam can bedelegated to the practice’s person-

Cataracta pulverulenta, as seen by Pentacam. 3 D Tomography of the eyes’ anterior segment.

nel also contributes to its economicefficiency. Analyzing the resultsand discussing them with the patient should be done only by theophthalmologist. Neuhann’s con-clusion: the Pentacam is a diagnostictool which helps all ophthalmolo-gists. With its ability to focus on several aspects like diagnosingglaucoma, preparing for cataractsurgery, the pre-operative planningand follow-up of refractive surgeryand the evaluation of keratoconusit enables the ophthalmologist toget an excellent overview of every-thing that matters in the anteriorsegment of the eye.