Patient is female, 25 years old and was referred to our clinic (Dec 2008) with the following noteworthy history and findings:
On Examination:Unaided eye vision RE = 6/60 LE =6/12Best corrected visual acuity with glasses: RE -3.00Dcyl x 20 6/18 LE -1.25DSph 6/6p RE shows obvious 360 degree surgical scar of keratoplasty with healthy graft. Keratometry: (Ref index of 1.332 CZ)(irregular mires + in all meridians) RE 52.0 @ 130 LE 45.0 @ 40↔ RE 6.38mm @ 130 LE 7.38mm @ 40 While LE was fitted with regular RGP lens and VA of 6/9 (clear) was achieved, RE did not tolerate regular RGP. The lens on RE was unstable, poorly tolerated and with marginal visual reward.
Patient was explained about Rose K Post Graft lens and she consented to try.
The trial lens tried was:
BC 6.60 (calculated empirically as 0.3mm steeper than average K). This was too flat.
Thus the final selected trial lens was:
Fluorescein pattern was practically parallel with good centration, stable vision and good subjective comfort.
VA on the dispensing visit OD = 6/6p, Fluoroscein fit good and ame as in trial fitting. Vision was stable and patient was very happy on achieving good vision in RE again.
A) The Rose K Post Graft lens performed better than regular RGP due to:
b) The power was calculated by adding the vertexed over-refraction to trial lens power.
c) Boston XO material was chosen because of the high Dk value (in order to provide near-natural oxygen flux through the lens to this already 'eventful' cornea).
D) Fluoroscein pattern through this Ultrviolet protected lens could be seen through the Wratten filter (Kodak filter #12)
E) Violet colour was chosen because our clinic fits Rose K2 lenses in blue. Just looking at violet colour in future (even before seeing patient data sheet) will give us an indication that this is Rose K PG lens.
In all, this was a very gratifying experience and a 'win-win' situation for manufacturer, dispenser and the patient.Rajesh WadhwaOptometrist, New Delhi, IndiaM.Optom.B.Ophth.Tech Hons.(AIIMS)B.Sc.Hons. (DU),Fellow of International Assoc. of Contact Lens Educators (Australia),PG Dip. in Management