KERATOCONUS: Profilometry-Based Scleral Lenses in Advanced Keratoconus Case
Daddi Fadel DOptom, FBCLA, FAAO, FSLS
History
- A 19-year-old Caucasian male was diagnosed with advanced keratoconus OU at age 19.
- He was not a candidate for corneal crosslinking as corneal thickness was less than 400um.
- He had an allergy to dust, mold, and pollen.
- He had never worn contact lenses.
- His request was to restore his vision and have comfortable contact lenses for sports, as he is a professional soccer player.
Examination
- Entering visual acuities (VAs):
OD: 20/66
OS: 20/40
- Refraction:
OD: +1.25 -3.25 x 93, 20/28
OS: +0.25 -2.00 x 96, 20/28
- Slit Lamp Examination:
| Lids/Lashes | Clean and Clear |
| Tarsal Conjunctiva | 1+ papillae |
| Bulbar Conjunctiva | No apparent irregularities or elevations, no staining with lissamine green |
| Cornea | Vogt’s Striae, enlarged corneal nerves, Fleischer’s ring, no staining with fluorescein application |
- Corneal Topography (Figure 1):
Cone Type: Centered
Cone Stage: Advanced
Sim K’s: OD Keratometry: 52.85 @ 040 / 73.06 @ 130
OS: 57.35 @ 125 / 63.75 @ 035
Eccentricity: OD: 1.37 / 1.40 OS: 1.28 / 1.37
Mesopic Pupil Diameter: OD: 7.1 mm OS: 7.00 mm
-
- Corneal Tomography (Figure 2: OS data are only reported)
K Max Front: 76.10 D
Thinnest Location: 398 µm
-
- Corneoscleral Profilometry (Figure 3: OS data are only reported)
At 16.90 mm Chord:
Ocular Sag: 4762 / 5046 µm
Scleral Toricity: 284 µm
-
- Horizontal Visible Iris Diameter (HVID): OD 12.30 mm, OS 12.20 mm
- Dilated Fundus Examination: No holes, breaks or tears OD, OS
Decision-Making Process
Considering the patient’s requests for comfort and correction during sports (soccer), scleral lenses were selected as the option to rehabilitate his vision.
Fitting and Evaluation
-
- Scleral lenses were designed empirically from corneoscleral profilometry, taking into consideration HVID, ocular sagittal height at 16.9 mm, similar to lens diameter. Over-refraction was performed for lens back vertex power (BVP).
- First dispense: In both eyes, the scleral lenses were well-centered and aligned on the conjunctiva, with no clinical signs indicating blanching or edge lifting. The central vault was around 300 µm. VA: 20/16 in both eyes.
- One-week follow-up visit: Scleral lenses have settled in both eyes with limbal touch, causing edema and myopic shift in both eyes. After lens removal, limbal arcuate staining was observed with epithelial bullae.
Figure 4: Corneal pachymetry – Baseline (left); After one week of lens wear (right)
