Visual performance of Rose K2 lenses in various corneal disorders- A case series Gauri Shankar Shrestha, M.Optom Fellow of International Association of Contact lens Educators Assistant Professor and Program Coordinator B.P. Koirala Lions Center for Ophthalmic Studies Institute of Medicine

Abstract Visual performance of Rose K2 contact lenses in various corneal refractive disorders- case series Gauri Shankar Shrestha, M.Optom, FIACLE, Assistant Professor, Maharajgunj Medical Campus, Tribhuvan University, email: gaurishshrestha@yahoo.com, phone: 9841019594 Background: Rose K2 family of lenses which are computer controlled complex geometric lenses that mimic the the cornea topography and are fitted in complex corneal refractive disorders to deliver optimal comfort, vision and physiological compatibility. These lenses are indicated in keratoconus, pellucid marginal degeneration, post-graft, corneal irregularities, corneal dystrophies and degenerations, post- refractive surgeries and so on where vision couldn’t be improved satisfactorily with other optical corrections. Purpose: To determine the visual performance of Rose K2 lenses in various refractive disorders. Method: seven patients with various corneal disorders that include four cases of keratoconus, two cases of corneal repair following penetrating injury, one case of corneal degeneration were enrolled in to the study. All the cases with keratoconus had experience of wearing ordinary RGP lenses. Visual acuity was measured with habitual lenses when applicable at baseline visit and with Rose K2 lenses at the completion of study. Questionnaires were used to assess contact lens comfort and self reported assessment of vision. Result: There was significant improvement in visual acuity in low and high contrast visual acuity chart. There were significant improvement in self reported comfort (79%) and self reported vision (90%) especially in advanced keratoconus, extreme toric cornea and unilateral cases of corneal disorders. Conclusion: Rose K2 has a successful fit rate in advanced keratoconus, extremely toric cornea, and unilateral cases. Patients’ preference also demonstrates the usefulness of Rose K2 lenses in clinical practice. Key Words: Rose K2, keratoconus, corneal degeneration, corneal truama

Vision in corneal disorders Cornea- an unique refracting element that has received interventional or non-interventional refractive correction Corneal disorders that causing corneal astigmatism can’t sometimes restore vision to normal even with proper refractive correction Fitting contact lens in such cases is itself a challenge in restoring vision, comfort and corneal physiology It is even challenging when the condition is unilateral Cornea- a uniquely structured refracting element of eye- 2/3 of total refractive power of eye Corneal disorders such as keratoconus, pellucid marginal disorders, corneal degenerations, corneal trauma results in irregular corneal astigmatism and a complex visual problem which sometimes can’t be restored with ordinary therapeutic measures Fitting contact lens in such cases is itself a challenge in maintaing optimal comfort and corneal physiology apart from restoring vision This effect is even challenging when the condition is unilateral

Contact lens for vision correction in corneal disorders There is a lack of general consensus on visual correction that suits in corneal disorders 40+ design available Recently Rose-K lens is being used to provide better visual performance and lens comfort

What is Rose K lens Rose K2 lenses are unique geometrically designed CL The goal is to bring all focal points onto the retina at a single point, regardless of BOZR or lens power by incorporating a specific eccentricity value in BOZ, stretching the optic zone without changing the fit Incorporating an aspheric base curve Manufacturing anterior curves relative to the posterior curves directly outside the BOZ Rose K2 lenses are unique geometric designed series of contact lenses. The design goal of the Rose K2 is to bring all focal points onto the retina at a single point, regardless of base curve radii or lens power incorporate a specific eccentricity value in BOZ, as well as stretching the optic zone without changing the fit, to create the desired results in improved vision and comfort The posterior surface has an aspheric base curve incorporated into the lens design and anterior curves are manufactured relative to the posterior curves directly outside the BOZ, which effectively increases the effective optic zone of the lens.

Lens very tight /Narrow bearing zone Large OZ ---advanced cone Advanced keratoconus

Wide bearing area Pooling eliminated I tried this but it didn’t work. WHY ask audience

ROSE K1 vs ROSE K2 ROSE K1 ROSE K2 Aspheric back surface Multiple back curves ROSE K2 Aspheric back surface

No Aberration Control Rose K 6.20 8.70 -17.75 Graph of power across optic zone -17.75 Again the power of the same lens in graph form showing the power increase that effectively occurs on a non aberration controlled lens. There is almost a dioptre of difference over an optic zone size of just under 5.00mm on a lens with a power in the centre of -17.75. -18.60 2.00 1.0 1.0 2.0 9

Aberration Control Rose K2 6.20 8.70 -17.75 Graph of power across optic zone This is the same lens showing the power readings in graph form. Across the optic zone of 5.00mm you can see that the power is consistent. Patients who require lenses with high power correction clearly benefit from lenses that are manufactured using aberration control. Keratoconus patients are an obvious group but not the only ones that will benefit from this type of manufacturing capability. Aberration controlled curves are applicable to both RGP and soft lenses whether moulded or lathe cut. -17.75 2.0 1.0 0.0 1.0 2.0 10

Eg 5.5/9.0/–16.50 std decreased lift ROSE K2 ECC VALUE OVER THE BOZ WILL CHANGE DEPENDANT ON : BASE CURVE POWER REFRACTIVE INDEX THICKNESS Eg 5.5/9.0/–16.50 std decreased lift Rose K2 -16.50 ecc = 0.578 If Power changed to –26.50 ecc = 0.628 If Base changed to 6.5 @-16.50 ecc = 0.593

Features of Rose K Lens Easy fitting Flexible edge lift system Extensive diameter and base curve Aberration control Advanced fitting options Fit all corneal shapes, sizes and stages of keratoconus

Rose K2 Designs Rose K2 Rose K2 NC Rose K2 IC Rose K2 PG Rose K2 XL Primary application Oval Cone NC Moderate and steep NC PMD, Keratoglobus, LASIK, Induced ectasia, PK, Keratoconus, PMD, PG, LASIK, any irregular cornea, 2ndary application Early PMD All NC Oval cone, Decentered cone, post trauma oval cone, NC, LASIK Polluted work condition, stability for sport or working environment Advanced fitting options Toric peripheral curve Asymmetric corneal quadrantic specific Toric back, front bitoric surfaces Reverse geometry lens periphery-IC design (Ghosting, glare and flare eliminated/reduced)

Identifying cone type using a topographer

Fitting characteristics Steep fit Flat fit Optimal fit

Edge Profile

Asymmetric corneal technology (ACT) Aapplied to posterior surface of lens at 6 o’clock to resove nferior edge lift Improve cornea to lens fitting relationship Improve comfort and lens positioning Asymmetric Corneal Technology is applied to the posterior surface of the lens at the 6 o’clock position to more closely fit a steeper inferior zone. The result is enhanced lens fit, comfort and stability, which helps resolve inferior edge lift-off and lower lid interact Traditionally, the only way to deal with inferior corneal steepening was to decrease the overall lens diameter to fit above or inside the steeper inferior quadrant. Unfortunately, this approach yields smaller optic zone diameters and associated halos, glare, ghosting and unstable Asymmetric Corneal Technology improves lens performance for the irregular cornea patient. lens positioning. Asymmetric Corneal Technology can be applied to any Rose K2 lens design (Figure 2). It simplifies fitting, is easy to use and will optimize final lens performance by improving the cornea-to-lens fitting relationship. This will improve comfort, lens positioning and corneal health, while reducing the number of office visits (chair time) needed to arrive at the final lens fit Traditional approach- ↓TD- Small OZD

Toric Peripheral curve

Materials and method Subjects 12 eyes of 7 patients 5 cases of B/L keratoconus as confirmed by Corneal topography One case with RE terrien’s marginal degeneration one case with LE corneal scars (traumatic) with pseudophakia

Keratoconus Experience with wearing spherical RGP lenses Visual acuity was measured with habitual lenses at baseline visit and with Rose K2 lenses at the completion of study (minimum 6 months) Topographic analysis was performed in each case Location of apex of the cone was determined select trial lens based on Sim K and type of corneal irregularities (Fitting guidelines)

Traumatic corneal scar with pseudophakia & Terrien’s marginal degeneration Have experience with trial of spherical RGP lenses BSCVA and Visual acuity with Rose K2 lenses at the completion of study was measured Keratometry/topography was performed

Severity of cone (Keratoconus) Mild <47D Moderate 47-52D Severe cone >52 D Classification of Astigmatism High astigmatism>3.00Dc Irregular- principal axis scews >10⁰

Fitting procedure A Rose K diagnostic lens set and fitting procedure were followed according to Rose K guidelines Based on initial lens fit on slit lamp, new trial lens base curve was chosen unless successful fitting was achieved A fit was considered successful if the patient achieved acceptable vision, comfort and corneal health. Final over refraction was determined after 30 minutes of lens fittings A Rose K diagnostic lens set and fitting procedure were followed according to Rose K guidelines. Based on initial lens fit on slit lamp, new trial lens base curve was chosen unless satisfactory/optimal fitting is achieved feather touch as the steepest curve, light bearing at mid-periphery and adequate edge lift and clearance Final over refraction was determined after 30 minutes of lens fittings.

Procedures After ordered Rose K lens was procured, patients were followed up in a week to make sure fitting of lens is OK Then patients were followed up in a month, three months and every six months Evaluation of contact lens comfort and self reported assessment of vision was considered for evaluation at least after 6 months

Procedures The questionnaire Patients were asked to report contact lens wearing time, number of lens removals per day, and self assessment of vision and comfort for each eye they were asked if they preferred the Rose K lenses or the habitual CLs Score: grade 1 to 10 (Comfort, vision & lens preference) (10 very comfortable, 1 very irritating)

Analysis Visual acuity was analysed by comparing the baseline visual acuity to the outcome visual acuity for each eye. A “flat eye” and a “steep eye” were designated for each patient based on the steep keratometric reading for each eye.

Case 1 (RK)- 19 yrs/M (Keratoconus) VA Unaided BSCVA Sph RGP Rose K Rx Sim K Remark Steep eye 1/60 6/18 6/6 -6.0/ -6.25 45.1/ 52.3 ACT/SFL Flat eye 5/60 6/5 -2.5/-1.75 43.1/ 45.3

Case 2 (JS)- 16 yrs/M (keratoconus) VA Unaided BSCVA Sph RGP Rose K Rx Sim K Remark Steep eye 4/60 6/12 6/6 6/5 -1.5/ -2.0 43/47.1 ACT Flat eye -2.0/-2.25 42.5/45.6 SSL

Case-3 (RK)- 20yrs /M Keratoconus VA Unaided BSCVA Sph RGP Rose K Rx Sim K Remark Steep eye 1/60 6/60 6/12 6/6 -12.0/ -4.5 56.7/ 63.5 ACT / TPC Flat eye 6/36 6/9 -8.0/ -4.0 54.2/56 ACT/ TPC

Case- 4 (AR)- 24yrs /M Keratoconus VA Unaided BSCVA Sph RGP Rose K Rx Sim K Remark Steep eye 6/36 6/18 6/9 +0.5/ -3.5 49.8/ 59.2 RK2 Flat eye 6/60 0.0/ -3.0 49.9/ 55.4 RK 2

Case 5 (MK), 15yr/F VA Unaided BSCVA Sph RGP Rose K Rx Steep eye CFCF 6/36 6/12 6/9 -18.0/ -6.0 Flat eye 6/6 +1.0/ -3.0

Case 6 (PH)- 20 yr/F VA Unaided BSCVA Sph RGP Rose K Rx Sim K Remark Steep eye CF 1ft 6/60 6/12 6/9 -8.0/-6.0 45.0/41.2 IC Flat eye 6/6 Soft lens -2.75 42.9/41.5

Case 7, 17yrs/F VA Unaided BSCVA Rose K Rx Sim K Remark Steep eye 6/60 6/18 6/6 +2.0/-6.0 39.0/ 50.5 XL Flat eye - -NA 0.00

Table: Analysis of variables b/w steep eye and flat eye Description Steep eye Flat eye p Mean Sim K±SD 52.15±5.81 51.06± 5.21 0.10 Q(4.5mm) -2.33±0.55 -2.01±0.86 0.14 Spherical equivalent RE -8.3±6.96 -6.1±5.84 0.13 No of trial 1.76±0.6 1.84±0.7 0.7 BSCVA (MAR) 5.28±3.45* 3.85±3.03** 0.04 S RGP (MAR) 1.41±0.49NS 1.2±0.40NS 0.40 Rose K (MAR)* 1.2±0.28 0.82 *0.01 * * 0.03

Self reported vision and comfort Eye Wearing time (hrs) Number of lens removal Self assessment of vision Comfort Lens preferences Case 1 SE 12 1 9 8 FE 5 6 Case 2 Case 3 14 2 7 Case 4 12-14 Case 5 Case 6 Case 7 10

Self reported vision and comfort Variables Steep Eye Flat Eye p Wearing time 12.14±2.03 12.33±2.01 0.71 Self assessment of vision 9±0.0 8±1.7 0.15 Comfort 7.3±0.75 7.6±0.54 0.44 Lens preferences 7.4±0.78 7.4±0.89 0.95

Self reported vision in Keratoconus Mild (<47.00D) Moderate (47-52.00 D) Severe (>52D) 7.66 ±2.3 9 8.83± 0.40 Self reported vision in toric cornea Up to 3.00 DC >3.00DC 7.75±1.98 9.0±0.0 Self reported vision in unilateral cases Self reported vision 9±0.0

Self reported comfort in keratoconus Mild (<47.00D) Moderate (47-52.00 D) Severe (>52D) 7.75±0.5 8 7.44± 0.83 Self reported comfort in toric cornea Up to 3.00 DC >3.00DC 7.25±0.5 7.41±0.67 Self reported comfort in unilateral cases Comfort 7±0.0

Discussion and Conclusion A practitioner with rose K lens may require average two lenses/trial for determining appropriate fitting Preliminary report suggest a successful fitting rate Regarding vision, No significant difference in visual acuity b/w SE and FE b/w Sph RGP and Rose K

Discussion and Conclusion relative appraisal of self reported vision and comfort Self reported vision apparently seen better with corneal steepening, high corneal toricity and unilateral cases

References Rose P. Unanswered questions letter. Contact Lens Spectrum 1999;14:15. Betts AM, Mitchell GL, Zadnik K. Visual Performance and Comfort with the Rose K Lens for Keratoconus. Optom Vis Sci 2002;79:493-501. Sudharman PM, Rathi V, Dumapati S. Rose K Lenses for Keratoconus—An Indian Experience. Eye Contact Lens 2010; 36(4):1-3. Jain AK, Sukhija J. Rose-K contact lens for keratoconus. Indian J Ophthalmol 2007;55:121-5.

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