Keratoconus is a slow progressive corneal disease that induces thinning of the cornea that will eventually cause the cornea to protrude and distort vision. Many will complain of blur, double vision, glare, and a general decrease in visual performance. This may impede one unable to function in
the way needed for work or even leisure. Fortunately, there are many companies creating scleral lenses to help with patients diagnosed with keratoconus. In many cases, keratoconus is first diagnosed in the teen years, in which corneal cross-linking is recommended to strengthen and halt
the progression of ectasia.
The best way to follow and manage keratoconus is with the use of a corneal topographer and an Ocular Coherence Tomography (OCT) instrument to evaluate the steepness and thickness of the compressed cornea. A corneal topographer is an instrument that maps the front surface of the cornea and will show the steepened area caused by keratoconus. OCT is an imagining technique that uses light to analyze the structures of the eye at a microscopic level, and in this case, we are able to image measure the thickness of the cornea and see the area of impairment. Using OCT, we are able to properly customize a scleral lens for ocular therapy and vision. With annual examinations, we will be able to analyze the topographical maps and OCT images to check for progression.
Usually, in the early stages of keratoconus, glasses, soft contact lenses, and rigid gas permeable corneal contact lenses will provide acceptable vision quality. This is also the time to consider corneal cross-linking to reduce the progression by strengthening the corneal fibers.
If the disease progresses, glasses and soft contacts lenses will not work well and the patient may be unable to achieve quality vision. This is a time to consider other modes of treatment, such as but not inclusive to, hybrid contact lenses, Rose K lenses, or scleral lenses.
At this point, careful monitoring is required to ensure the disease is not progressing. As the cornea continues to thin, the patient is at risk for hydrops which is when the corneal endothelium and Descemet’s membrane ruptures and the aqueous humor flows into the cornea causing pain, edema, and cloudy vision. Recent studies have shown a scleral lens can provide increased comfort and vision, and may reduce the need of a corneal transplant by 50%. In rare cases where keratoconus is untreatable with scleral lenses or other non-invasive techniques, a corneal transplant may be necessary.
Scleral lens technology is an amazing tool that can positively change lives by providing comfort and increasing visual acuity. I have witnessed many patients with severe keratoconus that have been stable with a clear vision for years without the need for a transplant with scleral lens treatment.
Other treatment modalities
There are various surgeries to help treat mild to severe keratoconus or other corneal ectatic pathologies. Corneal cross-linking (CXL) is a relatively new procedure in the United States. Using riboflavin (Vitamin B2) and ultraviolet light, the procedure strengthens the fibers of the cornea to strengthen the integrity of the cornea in order to try and halt the progression of ectasia. Many times surgeons will use CXL in combination with INTACS.
INTACS is a small intrastromal ring implanted into the cornea in order to flatten the steepened area of the cornea affected by keratoconus. Even though INTACS have helped many patients achieve better vision, studies have shown many may still need additional aid from glasses or even a scleral lens to produce sharper visual acuity.
Corneal transplants have become specialized and nuanced with advances in medical technology. When keratoconus is evaluated and deemed necessary for a transplant, a referral to a corneal ophthalmologist is necessary and at that time there will be a discussion on which type of transplant is best suited per case.
- Scleral Lenses Reduce the Need for Corneal Transplants in Severe Keratoconus. Koppen C, Kreps EO, Anthonissen L, Van Hoey M3, Dhubhghaill SN, Vermeulen L. Am J Ophthalmol. 2018 Jan;185:43-47. doi: 10.1016/j.ajo.2017.10.022. Epub 2017 Nov 16.
- Assessment of the Prosthetic Replacement of Ocular Surface Ecosystem (PROSE) scleral lens on visual acuity for corneal irregularity and ocular surface disease. ParraAS, Roth BM, Nguyen TM, et al. Ocul Surf. 2018 Apr;16(2):254-258. doi: 10.1016/j.jtos.2018.01.003. Epub 2018 Feb 6.
- Scleral lenses in the treatment of post-LASIK ectasia and superficial neovascularization of intrastromal corneal ring segments.Kramer EG, Boshnick EL. Cont LensAnterior Eye. 2015 Aug;38(4):298-303. doi: 10.1016/j.clae.2015.02.003. Epub 2015 Mar 4.
- Intracorneal Rings (INTACS SK) Might be Beneficial in Keratoconus; A Prospective Nonrandomized Study. A Ibrahim T, Elmor O. Med Hypothesis Discov InnovOphthalmol. 2013 Summer;2(2):35-40.