|Year : 2021 | Volume
| Issue : 1 | Page : 2-4
Visual rehabilitation using miniscleral lens in advanced keratoconus
Sudhakar Potti, Aparna N Nayak
Department of Cornea, Sankara Eye Hospital, Guntur, Andhra Pradesh, India
|Date of Submission||03-Sep-2020|
|Date of Acceptance||05-Dec-2020|
|Date of Web Publication||27-Mar-2021|
Dr. Aparna N Nayak
Sankara Eye Hospital, Guntur - Vijayawada Expressway, Pedakakani, Guntur - 522 509, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
Aim: The aim of this study is to visually rehabilitate patients with advanced keratoconus with miniscleral contact lens. Materials and Methods: Miniscleral lens were prescribed in 11 eyes of 8 patients with advanced keratoconus. Inclusion criteria Amsler Krumeich Grade 2 with poor spectacle corrected visual acuity (<0.5logMAR) for the duration of 1 year. Results:Mean age was 18.75 years. Males and females were 50% each. Mean of uncorrected, spectacle corrected, best-corrected visual acuity with contact lens was 1.28logMAR, 0.96logMAR, and 0.12logMAR, respectively. Visual improvement was minimal with spectacles (0.5 Snellen lines, 0.32logMAR), whereas miniscleral contact lens showed additional improvement of 4.5 Snellen lines (1.16logMAR), respectively. Conclusion: Visual rehabilitation with miniscleral contact lens in advanced keratoconus showed excellent improvement in visual acuity and reduced the need for corneal transplantation.
Keywords: Advanced keratoconus, miniscleral lens, nonsurgical management of advanced keratoconus
|How to cite this article:|
Potti S, Nayak AN. Visual rehabilitation using miniscleral lens in advanced keratoconus. TNOA J Ophthalmic Sci Res 2021;59:2-4
| Introduction|| |
Keratoconus is an asymmetrical, noninflammatory, progressive ectatic condition of the central cornea that results in diminution of vision because of irregular astigmatism. In general, spectacles are prescribed in the early stages when the astigmatism is mild. In moderate stages, rigid contact lenses play a major role in visual improvement. In advanced cases, deep anterior lamellar keratoplasty (DALK) or penetrating keratoplasty (PKP) is the treatment of choice. Gomes and a group of Global Delphi Panel of keratoconus panelists came to a conclusion that contact lens intolerance was the leading indication for DALK, while corneal scarring was the most important indication for PKP. In our study, we have tried miniscleral lens in visual rehabilitation in advanced keratoconus.
Contact lens technology has advanced over the years, with emphasis on scleral contact lenses. These lenses mainly rest on the perilimbal sclera and vault over the cornea and limbus. Both rigid corneal lens and sclera lens correct irregular astigmatism with the help of the tear lens and the rigid anterior surface. The advantages of scleral over corneal lenses in the correction of irregular astigmatism are multiple: scleral lens provides a stable and better-centered fit; do not touch the cornea and is very comfortable, thereby improving the quality of life. They can be adapted to fit in almost any degree of corneal ectasia by changing the optic zone vault. Deloss et al. showed that eyes with advanced corneal ectasia can be successfully fitted with prosthetic replacement of the ocular surface ecosystem scleral contact lenses. They concluded that the visual outcomes for Stage 4 corneal ectasia was better and rapid with nonsurgical management (scleral contact lens) compared to surgical (PKP). We selected the cases of advanced keratoconus and rehabilitated with miniscleral lens, the outcomes of which are described in this study.
| Materials and Methods|| |
This is a retrospective case series of patients attending Cornea Clinic in Sankara Eye Hospital, Guntur, Andhra Pradesh, India, over a 1-year period. Ethics committee approval for data collection and analysis was obtained from the Institutional Ethics Committee.
Eleven eyes of eight advanced keratoconus patients were included in the study. Diagnosis was done using the slit-lamp examination and Pentacam (Wavelight® Oculyzer™ II). Keratoconus was classified using Amsler Krumeich Criteria and more than Grade 2 with poor spectacle corrected visual acuity (<0.5logMAR; Snellen 6/12) were included in our study. All these patients were intolerant to corneal rigid lens or had an unstable fit. A trial fitting of miniscleral contact lens was offered to all patients [Figure 1] and [Figure 2]. The lens design used was the Purecon McAsfeer Mini-Scleral lens. The lenses are made of highly gas-permeable materials and have a diameter of 16 mm. Anterior segment optical coherence tomography was done to check the vault of the lens in all cases [Figure 3].
|Figures 1: Slit-lamp photograph showing ideal fit of miniscleral lens in advanced keratoconus. Diffuse and fluoroscein stained, respectively|
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|Figure 2: Slit-lamp photograph showing ideal fit of miniscleral lens in advanced keratoconus. Diffuse and fluoroscein stained respectively|
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|Figure 3: Anterior segment optical coherence tomography showing vault of the miniscleral contact lens|
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| Results|| |
Eleven eyes of eight patients were included in our study [Table 1]; mean age was 18.75 years. Proportion of males and females was equal (50%). Mean of uncorrected, spectacle corrected, and best-corrected visual acuity (BCVA) with contact lens was 1.28logMAR, 0.96logMAR, and 0.12logMAR, respectively. Visual improvement was minimal with spectacles (0.5 Snellen lines, 0.32logMAR), whereas miniscleral contact lens showed additional improvement of 4.5 Snellen lines (1.16logMAR), respectively. One patient had exotropia with amblyopia did not benefit from contact lens wear, whereas the other eye had good improvement in visual acuity. Another patient came with unilateral iatrogenic keratoconus, postlaser-assisted in situ keratomileusis both eyes, showed reasonable improvement in visual acuity from 6/60 (logMAR1.00) to 6/12 (logMAR0.3). Opposite eye was stable with BCVA of 6/9 (logMAR0.9).
|Table 1: Patient demographic data and outcomes of miniscleral lens in advanced keratoconus|
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| Discussion|| |
There have been advances in the management of keratoconus. Multiple studies have been published that have rewritten the options for keratoconus management. McGhee et al. described a management paradigm for moderate-to-severe keratoconus with poor BCVA. For mild-to-moderate cases, contact lenses are classified as a conservative mode of treatment. Parker et al. reviewed the treatment options available for advanced keratoconus, although contact lenses are only discussed in the context of cases where lens wear is mainly needed to supplement transplant or keratorefractive surgery. With presently available lens designs, there is technically no limit for which keratoconus cases can be successfully treated with contact Lenses. Our study shows that eyes with advanced keratoconus can achieve satisfactory functional visual acuity with miniscleral contact lens.
Barnett et al. showed that the learning aspect of insertion and removal of scleral lenses was an obstacle to contact lens wear in one-third of the patients. Before scleral lenses became available, corneal contact lens intolerant patients would have undergone keratoplasty, instead, they are now wearing scleral lenses with good success rate. However, scleral lenses are looked upon as unpractical and costly. Mannis quotes why patients should not lightly make the choice for keratoplasty: “The patient who opts for a corneal transplant trades one set of problems for another.” One gives up contact lens for better visual acuity postkeratoplasty. With this procedure, comes the risk of complications such as corneal astigmatism, anisometropia, cataract, infection, glaucoma, graft rejection, and ocular surface inflammation. DALK has solved some of these issues mentioned, specifically with respect to vision and graft rejection. Patients should be carefully informed regarding the risk of requiring additional refractive surgery and/or contact lens correction to correct postkeratoplasty astigmatism. One patient in our study had undergone DALK in the opposite eye previously and his BCVA was 6/12 (logMAR0.3) which is lesser than that of patients who were visually rehabilitated with miniscleral lens. This clearly demonstrates the superiority of miniscleral lens over DALK for visual rehabilitation in advanced keratoconus. The major advantage of scleral lens over keratoplasty is total reversibility. Our treatment strategy for advanced keratoconus is mainly focused on miniscleral contact lens. Almost all have satisfactory vision and the need for surgical intervention and its complications can be prevented with the use of miniscleral lenses. Patients are explained regarding all the nonsurgical and surgical options available and are tailored based on individual's need.
| Conclusion|| |
Strength of the study that it is a large case series and limitations are that there are no controls in our study. From our study, we can interpret that we can visually rehabilitate patients with advanced keratoconus without the need for keratoplasty. In future, prospective study with larger sample size maybe required.
Visual rehabilitation with miniscleral contact lens in advanced keratoconus showed excellent improvement in visual acuity and reduced the need for corneal transplantation.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Gomes J, Tan D, Rapuano CJ, Belin MW, Ambrosio R Jr., Guell JL, et al
. Global concensus on keratoconus and ectatic diseases. Cornea 2015;34:359-69.
Deloss K, Fatteh NH, Hood CT. Prosthetic replacement of the ocular surface ecosystem scleral device comparted to keratoplasty for the treatment of corneal ectasia. Am J Ophthalmol 2014;158:974-82.
Mcghee CN, Kim BZ, Wilson PJ. Contemporary treatment paradigms in keratoconus. Cornea 2015;34 Suppl 10:S16-23.
Parker J, van Dijk K, Melles GR. Treatment options for advanced keratoconus: A review. Surv Ophthalmol 2015;60:459-80.
Barnett M, Lien V, Li JY, Durbin-Johnson B, Mannis MJ. Use of scleral lenses and miniscleral lenses after penetrating keratoplasty. Eye Contact Lens 2016;42:185-9.
Mannis MJ. Keratoconus: Why and when do we turn to surgical therapy. Am J Ophthalmol 2006;142:1044-5.
[Figure 1], [Figure 2], [Figure 3]