KERATOCONUSCASE: Profilometry-Based Scleral Lenses in Advanced Keratoconus
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 allergies to dust, mold, and pollen.
- He had never worn contact lenses.
- His goal 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):
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)
Figure 2
K Max Front: 76.10 D
Thinnest Location: 398 µm
-
- Corneoscleral Profilometry (Figure 3: OS data are only reported)
Figure 3
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: For 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 settled on 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)
Figure 5: Peripheral corneal and limbal staining caused by scleral lens limbal touch
- New lenses were designed, increasing peripheral corneal and limbal vault.
-
- One-week follow-up visit: The new scleral lenses were well-centered and aligned on the conjunctiva, with no clinical signs indicating blanching or edge lifting. The central vault was around 350 µm with adequate peripheral corneal and limbal clearance. VA: 20/16 in both eyes. The lenses had settled, but there was still a sufficient vault over the limbus. VA: 20/16 in both eyes.
- One-month follow-up visit: All findings remained consistent with the one-week follow-up, and the patient was satisfied with the quality of vision and wearing time comfort.
-
- Plan: Lenses were finalized.
Clinical Pearls
- Listening to patients’ needs is crucial when fitting specialty contact lenses.
- Scleral lenses are an optimal option for patients with keratoconus to consider for visual rehabilitation, offering comfort and lens stability in the eyes, especially for those with advanced keratoconus who practice sports activities.
- Proper evaluation of the lens fit is crucial for maintaining corneal health over time.
- Limbal touch may cause staining and edema.
- Pachymetry is essential when fitting scleral lenses to monitor corneal health and detect edema less than 4%, which does not present clinical signs visible at slit lamp observation.
- Scleral lens fitting is considered successful if ocular health is maintained over time.