PENTACAM and PENTCAM HR Instruction Manual June 2008

Foreword We thank you for the trust you have put in this OCULUS product. With the purchase of this instrument, you have chosen a modern, sophisticated product, which was manufactured and tested according to strict quality standards. Our company has been doing business for over 100 years. Today, OCULUS is a mediumsized company concentrating competely on helping ophthalmologists, optometrists and opticians to carry out their responsible work by supplying an optimal range of instruments for examinations and surgery on the eye. The Pentacam is based on the Scheimpflug principle, which generates precise and sharp images of the anterior eye segment. Oculus has produced an instrument that takes extremely accurate measurements and is easy to use. If you have questions or desire further informations on this product, call, fax or email us. We will be glad to help you. OCULUS Optikgeräte Managing director and The Management Team

OCULUS is certified according to DIN EN ISO 9001:2000 and 13485:2003, setting high standards of quality where development, manufacture, quality assurance and service regarding the entire range of products are concerned.

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Interpretation Guideline Pentacam® / Pentacam HR® (IG/70700/0608/en)

Table of Contents

Table of Contents 1 Introduction ...1 2 Description of unit and general remarks...1 3 Corneal Ectasia ...2 3.1 Case 1, Ectasia after RK, Renato Ambrósio, Jr, MD ...2 3.2 Case 2, Ectasia after LASIK?, Prof. Michael Belin ...4 4 Glaucoma...7 4.1 4.2

Case 1, General screening, Tobias Neuhann, MD...7 Case 2, YAG Laser Iridectomy, Eduardo Viteri, MD...8 4.2.1

Comments ... 10

5 Screening for refractive surgery, Prof. Michael Belin ...10 5.1

Screening Parameters, 4 maps refractive display Prof. Michael Belin ... 10 5.1.1 5.1.2 5.1.3

Suggested Installation Settings... 10 Strategy on how to go through the exams ... 11 Proposed screening parameters ... 11

5.2 Normal, astigmatic cornea, Prof. Michael Belin ... 13 5.3 Normal, astigmatic cornea, Prof. Michael Belin... 14 5.4 Normal, astigmatic cornea, Prof. Michael Belin ... 15 5.5 Astigmatism on the posterior cornea, Prof. Michael Belin ... 16 5.6 Spherical cornea, Prof. Michael Belin ... 17 5.7 Thin, spherical cornea, Prof. Michael Belin... 18 5.8 Thin cornea, Prof. Michael Belin... 19 5.9 Borderline case, Prof. Michael Belin ... 20 5.10 Displaced apex, Prof. Michael Belin... 21 5.11 Pellucid Marginal Degeneration, Prof. Michael Belin... 22 5.12 Asymmetric Keratoconus, Prof. Michael Belin ... 23 5.13 False negative on curvature map, Prof. Michael Belin... 25 5.14 Keratoconus OD > OS, Prof. Michael Belin... 26 5.15 Classic Keratoconus map, Prof. Michael Belin ... 27 6 Corneal Thickness profile, Renato Ambrosio, MD ...28 6.1 Screening for Ectacia Renato Ambrosia, Jr. MD, Marcela Q. Salomão, MD... 31 6.2 6.2 Case 1, Fuchs Dystrophy, R. Ambrosio, Jr. MD, M. Salomão, MD... 35 6.3 Case 2, Ocular Hypertension, R. Ambrosio, JR. MD, M. Salomão, MD ... 36 6.4 Case 3, Early Fuchs Dystrophy with Glaucoma, R. Ambrosio, Jr. MD, M. Salomão, MD ... 38 6.5 Screening parameter’s, Renato Ambrosio, Jr. MD... 41 7 Belin/Ambrosio Enhanced Ectasia...42 7.1 Introduction... 42 7.2 Basics... 42 7.3 Standard and enhanced fitted reference sphere (BFS)... 42 7.4 Interpretation of the Belin/Ambrosio Enhanced Ectasia Display ... 45 7.5 Pachymetry evaluation ... 46 8 Ectasia susceptibility shown in the Belin/Ambrosio (B/A) Enhanced Ectasia Display...47

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Table of Contents

9 Locating the cone, Prof. Michael Belin...50 10 INTACS® implantation ...51 10.1 Case 1, Prof. Michael Belin ... 51 10.2 Case 2, INTACS® after PRK, Alain-Nicolas Gilg, MD... 53 11 Differences between Placido and elevation derived curvature maps ...56 11.1 Keratoconus, OD & OS?, Prof. Michael Belin... 56 11.2 Form Fruste Keratoconus?, Prof. Michael Belin ... 59 12 Diagnosing ectasia and pseudo-ectasia: P. Vinciguerra M.D, M.I. Torres Munoz M.D ...62 12.1 12.2 12.3 12.4

Introduction... 62 The normal Cornea... 62 Ectasia: the key to diagnosis ... 64 Interlocking relationships between curvature-elevation-pachymetry maps ... 64 12.4.1 12.4.2 12.4.3 12.4.4 12.4.5

Preliminary considerations... 64 Maximum curvature, maximum anterior and posterior elevation and the point with minimal pachymetry... 65 Analysis of the highest points of the anterior and posterior face... 66 Eccentric position of the thinnest point... 68 Map patterns... 68

12.5 Conclusions and noteworthy points ... 69 13 Holladay Report...70 13.1 Detecting forme fruste Keratoconus... 70 14 IOL calculation for patients after refractive surgery ...72 14.1 EKR’s in the Holladay Report... 72 14.2 Details of the Holladay Report... 73 14.3 High myopic refractive change after LASIK, Tobias Neuhann, MD... 75 15 phakic IOL implantation...76 15.1 Manual pre-op simulation and post-op control, Eduardo Viteri, MD ... 76 15.1.1 15.1.2

Preoperative evaluation... 76 Postoperative evaluation... 77

15.2 3D - phakic IOL simulation, Burkhard Dick, MD, Sabine Buchner, Optometrist... 78 15.2.1 15.2.2

Myopic Artisan / Verisyse 6 / 8.5 mm ... 78 Toric Artisan / Verisyse, 5 / 8.5mm... 81

15.3 Patients selection criteria, Burkhard Dick, MD, Sabine Buchner, Optometrist... 84 16 From the daily practice ...85 16.1 Case 1, Cortical Cataract, Tobias Neuhann, MD... 85 16.2 Case 2, Corneal transplant, removing the sutures?, Tobias Neuhann, MD... 86 16.3 Case 3, Keratoconus and Cataract, Tobias Neuhann, MD... 87 16.4 Case 4, Corneal Infiltrate, Renato Ambrósio, Jr, MD... 90 16.5 Case 5, Incisional Edema, Renato Ambrósio, Jr, MD ... 92 16.6 Case 6, Corneal Thinning after Herpetic Keratitis, Renato Ambrósio, Jr, MD... 93 16.7 Case 7, Epithelial Ingrowth after Keratomileusis in situ, Renato Ambrósio, Jr, MD... 94 17 Scheimpflug and Slit lamp images ...96 17.1 Corneal Dystrophy ... 96

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Table of Contents

17.2 Congenital anterior pyramid cataract ... 97 17.3 Posterior Capsular Cataract ... 98 17.4 Nuclear Cataract... 99 17.5 Posterior Synechia ...100 17.6 Pterygium ...101 18 Orthokeratology ... 102 18.1 Case 1, General Screening, Alain-Nicolas Gilg, MD ...102 19 Recommended Settings and Color Maps ... 104 19.1 Recommended Settings...105 19.2 Recommended Color Maps ...105 19.2.1 19.2.2 19.2.3 19.2.4

Screening for LASIK, PRK etc. ...105 Screening for pIOL implantation...105 Glaucoma Screening ...106 IOL Calculation for Treated and Untreated Corneas ...106

20 List Of illustrations ... 104 21 References and Contact Addresses ... 107

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1 Introduction

1

Introduction

This guideline should help all Pentacam users to interpret the results and screens the Pentacam provides. We may not have covered everything which might be of interest. Therefore we ask each Pentacam user for help to improve this guideline step by step. Please forward your special cases to us and we will be happy to implant them. Of course, this guideline cannot replace the years of experience and the medical studies, but it will be a help in questionable cases as well as a help for beginners. The personal experience and impression from each of you and the cross connection of the results from different instruments linked with the individual patient’s history may sometimes lead to different results as shown in this guideline.

2

Description of unit and general remarks

The OCULUS Pentacam/Pentacam HR is a rotating Scheimpflug camera. The rotational measuring procedure generates Scheimpflug images in three dimensions, with the dot matrix fine-meshed in the center due to the rotation. It takes a maximum of 2 seconds to generate a complete image of the anterior eye segment. Any eye movement is detected by a second camera and corrected for in the process. The Pentacam calculates a 3-dimensional model of the anterior eye segment from as many as 25.000 (HR: 138.000) true elevation points. The topography and pachymetry of the entire anterior and posterior surface of the cornea from limbus to limbus are calculated and depicted. The analysis of the anterior eye segment includes a calculation of the chamber angle, chamber volume and chamber height and a manual measuring function at any location in the anterior chamber of the eye. In a moveable virtual eye, images of the anterior and posterior surface of the cornea, the iris and the anterior and posterior surface of the lens are generated. The densitometry of the lens is automatically quantified. The Scheimpflug images taken during the examination are digitalized in the main unit and all image data are transferred to the PC. When the examination is finished, the PC calculates a 3D virtual model of the anterior eye segment, from which all additional information is derived.

Attention OCULUS Optikgeräte GmbH emphasizes that the user bears the full responsibility for the correctness of data measured, calculated or displayed using the Pentacam. The manufacturer will not accept claims based on erroneous data and wrong interpretation. This interpretation guideline has to be understood as a help only to interpret the examination data the Pentacam provides. The doctors and physicians have to consider all medical information which can be collected by using other diagnostic instruments e.g. slit lamp examination, ultrasound biomicroscopy, etc. to make the diagnosis. The results of the different diagnostic instruments have to be compared and closely scrutinized. This interpretation guideline has to be understood as a completion to the Users Guide. The current version of the Users Guide and the Interpretation Guideline are on every Pentacam Software CD-ROM and should be read by all users prior to use.

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3 Corneal Ectasia

3

Corneal Ectasia

3.1

Case 1, Ectasia after RK, Renato Ambrósio, Jr, MD

A 28-year old male patient had RK in 1995 for myopic astigmatism with RK enhancement three years later in OS. Corneal topography was not performed prior to surgery according to patient information. Uncorrected VA was 20/30 in OD and 20/200 in OS. Patient refers severe glare and starburst all day, mainly at night. Refraction is –0.25 –3.00 x 156, giving 20/20 in OD and –5.00 –2.25 x 39, giving 20/30 in OS. Patient was fit with a RGPCL with significant improvement of the symptoms in both eyes. The Pentacam Quad map demonstrates corneal Ectasia in both eyes, more advanced in OS (Figure 2). In OD, (Figure 1) the patient has a central cornea with less distortion than OS, which enables relatively good uncorrected vision. However, the patient refers quality of vision was terrible in both eyes.

Figure 1, Pentacam, OD post LASIK, Ectasia

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3 Corneal Ectasia

Figure 2, Pentacam, OS post LASIK, Ectasia

Figure 3, Pachymetry Progression, OD

Figure 4, Pachymetry Progression, OS

The pachymetric progression is abrupt in both eyes as an important sign of Ectasia, (Figure 3 and Figure 4). Probably mild Ectasia could have been diagnosed prior to surgery if corneal topography and tomography would have performed and well interpreted. This case would have been considered as a bad candidate for RK.

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3 Corneal Ectasia

3.2

Case 2, Ectasia after LASIK?, Prof. Michael Belin

A 46 year old female had previous LASIK 2 years prior. She presented interested in an enhancement to her dominant right eye. BSCVA was 20/20+ with – 1.25 D. The referring surgeon was concerned about Post LASIK Ectasia based on Orbscan topography. Orbscan topography shows significant posterior elevation (Figure 5).

Figure 5, ORB Scan post LASIK, Ectasia

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3 Corneal Ectasia

Evaluation with the OCULUS Pentacam reveals no posterior elevation abnormality and no evidence of post-operative Ectasia (Figure 6). Patient underwent a routine LASIK enhancement without incident.

Figure 6, Pentacam 4 maps, post LASIK no Ectasia

This case demonstrates one of the limitations with the current version of the B&L Orbscan®. The Orbscan® routinely fails to correctly identify the posterior corneal surface in post-operative patients leading to underestimates of residual bed thickness and frequent incorrect diagnosis of post LASIK Ectasia.

☞

Discussion

Here the Orbscan® incorrectly reads the corneal thickness 37µm thinner than the Pentacam and shows an incorrect Ectasia (Figure 5). The Pentacam shows a normal post-operative appearance (Figure 7).

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3 Corneal Ectasia

Orbscan Pachymetry is 37 µm thinner

Figure 7, Orbscan® 4 Maps, Pentacam 4 Maps Refractive

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4 Glaucoma

4

Glaucoma

4.1

Case 1, General screening, Tobias Neuhann, MD

A 48 year old white male patient wants to have a second opinion about his glaucoma treatment. His father and grandfather have had glaucoma. He himself has had ten years of glaucoma medical treatment. His ophthalmologist recommends now a second medication. We measured 24mmHG with Goldmann applanation tonometer.

Figure 8, Pentacam 4 maps

After taking a Pentacam examination, looking to the 4 maps display (Figure 8), we put the 24mmHg in the Dresdner scale and the corrected IOP was displayed with 11mmHg because of a corneal thickness of about 728µm in the apex.

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4 Glaucoma

The additional examination on HRT resulted in a healthy optic nerve and we recommend the patient to stop his medication. His IOP today is during daytime between 19 and 22mmHg. We still see him 4 times a year for IOP and HRT check (Figure 9, Figure 10).

Figure 9, HRT Image

4.2

Figure 10, HRT Image

Case 2, YAG Laser Iridectomy, Eduardo Viteri, MD

This is a 64 year old female patient who was complaining of episodes of blurred vision and tearing. The IOP was 18 mm Hg in both eyes. Anterior chamber was shallow on slit lamp examination and optic nerve had a C/D ratio of 0.6 in both eyes. The lens was clear and gonioscopy exam revealed a narrow angle in both eyes (grade I-II). The anterior segment exam with the Pentacam (Figure 11) documented an irido-corneal angle of 22.5 degrees with an ACD (epithelial) of 2.43 mm. The patient was reluctant to have YAG laser Iridectomy until she was able to compare her anterior segment biometry with that of other normal patients.

Figure 11, Pentacam Overview post op to YAG laser Iridectomy

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4 Glaucoma

After YAG Laser Iridectomy was performed, several of her anterior segment measurements changed (Figure 12). This is quite evident in the differential display (Figure 13).

Figure 12, Pentacam Overview, 10 days after YAG Laser Iridectomy

Figure 13, Pentacam, 2 maps comparison

The irido-corneal angle is 4º wider, and, although the ACD only deepened 0.09 mm centrally, the main difference is evident in the periphery, where you can see changes ranging from 0.19 mm to 0.30 mm. This was enough to increase the AC volume from 64 to 92 mm3.

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5 Screening for refractive surgery, Prof. Michael Belin

4.2.1

Comments

In narrow angle Glaucoma, the Pentacam is quite useful in measuring the irido-corneal angle, although this may be difficult in 360º because of the eyelid interference. We can obtain more consistent data when measuring peripheral ACD and AC volume. The exam has been of great help also in educating the patient about this disease, and making evident the effect of the treatment.

5

Screening for refractive surgery, Prof. Michael Belin

5.1

Screening Parameters, 4 maps refractive display Prof. Michael Belin

5.1.1

Suggested Installation Settings

The following are my guidelines for pre-operative refractive surgery screening for Keratoconus: „

Use the 4 maps refractive display showing Anterior Elevation, Posterior Elevation, Pachymetry and anterior Sagittal Curvature. It is based to keep the display, scales and colors constant for refractive screening as this will allow for a rapid visual inspection.

Pachymetry Î Right click on the scale and set "ABS NORMAL", (300-900 µm) Î

Right click on the actual display for the drop down menu. Turn ON the following (Apex #1), Thinnest ( #2), Pupil Edge ( #6), Nasal/Temp ( #7), Max Diam 9.0 ( #11) and Show Numeric ( #13).

Anterior Elevation & Posterior Elevation Î Right click on scale and set to

"Belin Intuitive" +/- 75 microns for refractive practice „ "Belin Intuitive" +/- 150 microns for medical practice „ BFS Sphere, Float, MAN, BFS diameter set to 9.0 mm or 8.0 mm. „ On the 9.0 mm display you should have none or minimal extrapolated data for the study to be valid. Î Right click on display and turn ON Apex (#1), Thinnest (#2), Pupil Edge (#6), Nasal/Temp (#7), Max Diam9.0 (#11) and Numeric (#12). „

Sagittal Curvature Î Right click on scale and set to ABS NORMAL, AMERICAN and Diopter Î

Right click on the display and set to Min Radius (#3), Pupil Edge (#6), Nasal/Temp (#7), Max Diam 9.0 (#11), Numeric (#12) and Min/Max (#13).

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5 Screening for refractive surgery, Prof. Michael Belin

Note The different borderline numbers for the elevation maps are depending on the BFS diameter you are using, 9 mm or 8 mm.

5.1.2

Strategy on how to go through the exams

The way I am usually going through the exams is: Î Î Î Î Î

Look at anterior elevation first Look at posterior elevation Look at the Pachymetry and thickness distribution off center distribution of corneal thickness is highly suspicious Look at the symmetry of both eyes if one eye is abnormal, usually both eyes are abnormal Look at curvature last

5.1.3

Proposed screening parameters

It is essential to check the settings for the fitting zone of the BFS in the settings of the Pentacam since this influences the borderline numbers (Figure 14).

Figure 14, BFS fitting zone

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5 Screening for refractive surgery, Prof. Michael Belin

„

If you are using the 9mm zone for fitting the BFS, the proposed screening parameters I am using are:

In the anterior elevation map differences between the BFS and the corneal contour less than +12µm are considered normal between +12 µm and +15µm are suspicious more than +15µm are typically indicative of keratoconus Similar numbers about 5µm higher apply to posterior elevation maps „

If you are using the 8mm zone for fitting the BFS, the proposed screening parameters I am using are: Anterior Elevation differences less than +8µm are considered in the normal range Anterior Elevation differences > +8µm are typically indicative of keratoconus or other ectatic disorders (in the central zone) Posterior Elevation differences >11µm are considered in the normal range Posterior Elevation differences >16µm are suspicious

Note The above relate to elevation ISLAND patterns, not astigmatism. These numbers pertain to elevation in the central and paracentral region in an island pattern.

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5 Screening for refractive surgery, Prof. Michael Belin

5.2

Normal, astigmatic cornea, Prof. Michael Belin

This 4 picture composite map (Figure 15) shows a normal with the rule astigmatic cornea (both anterior and posterior surfaces). The sagittal curvature appears normal as would be expected from the normal symmetric anterior elevation and the pachymetry map reveals a normal thickness with a normal pachymetry distribution. DIAGNOSIS - Normal Astigmatic Cornea

Figure 15, Pentacam, astigmatic cornea

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5 Screening for refractive surgery, Prof. Michael Belin

5.3

Normal, astigmatic cornea, Prof. Michael Belin

This map (Figure 16) demonstrates a normal with-the-rule astigmatic cornea (2.6 D cylinder), Figure 15. Both the anterior and posterior elevations demonstrate a similar pattern as does the anterior sagittal curvature. The curvature maps reveals a steep cornea (K1 = 47.6, K2 = 50.2) but the elevation maps do not reveal any suspicious areas. The pachymetry map is well centered with a thinnest reading of 546 microns. This is a normal astigmatic corneal with steep curvature, but otherwise normal. DIAGNOSIS - Normal Astigmatic Eye

Figure 16, Pentacam, astigmatic cornea

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5 Screening for refractive surgery, Prof. Michael Belin

5.4

Normal, astigmatic cornea, Prof. Michael Belin

This map (Figure 17) demonstrates a normal with-the-rule astigmatic cornea (4.1 D). Both the anterior and posterior elevations demonstrate a similar pattern as does the anterior sagittal curvature. The anterior elevation map is symmetric the curvature shows a symmetric astigmatic pattern. The pachymetry map is well centered with a thinnest reading of 522 microns. DIAGNOSIS - Normal Astigmatic Eye

Figure 17, Pentacam, astigmatic cornea

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