Boston ocular surface prosthesis: An Indian experience

Abstract

Context:Boston ocular surface prosthesis (BOSP) is a scleral contact lens used in the management of patients who are rigid gas permeable (RGP) failures as with corneal ectasias such as keratoconus and in those patients who have ocular surface disease such as Stevens–Johnson syndrome (SJS).Aim:To report utilization of BOSP in a tertiary eye care center in India.Materials and Methods:We retrospectively reviewed charts of 32 patients who received BOSP from July 2008 to May 2009. Indications for fitting these lenses, improvement in visual acuity (VA) before and after lens fitting and relief of symptoms of pain and photophobia were noted. Paired t-test was used for statistical analysis using SPSS version 16.0 for Windows.Results:Thirty-two patients (43 eyes) received these lenses. These consisted of 23 eyes of 17 patients who failed RGP trials for irregular astigmatism and corneal ectasia such as keratoconus and post radial keratotomy and scar and 20 eyes of 15 patients with SJS. Mean age of RGP failures was 27.94 years. Pre- and post-BOSP wear mean LogMAR VA was 1.13 and 0.29, respectively, in RGP failures. The P value was statistically significant (P < 0.001). In patients with SJS, LogMAR VA was 0.84 ± 0.92 before and 0.56 ± 0.89 after lens wear. The P value was statistically significant (P < 0.001). VA improved by >2 lines in 7/20 eyes (35%) with SJS, with improvement in symptoms.Conclusion:BOSP improves VA in patients who have irregular astigmatism as in ectasias and RGP failures and improves vision and symptoms in patients with SJS.

Management of advanced corneal ectasias

“…The Rose-K CL provides greater comfort, better quality of vision and requires less chair time in cases with keratoconus 29 30 33. The Rose K2 IC is a large diameter, intralimbal lens that can be used for large or oval cones 28 .…”

“…These lenses rest on the sclera and do not touch the cornea. There is a constant pool of tears over the cornea, which acts as a liquid corneal bandage and avoids any friction between the posterior surface of the CL and the corneal apex 33. In addition these lenses mask corneal surface astigmatism and improve best-corrected VA 33.…”

“…There is a constant pool of tears over the cornea, which acts as a liquid corneal bandage and avoids any friction between the posterior surface of the CL and the corneal apex 33. In addition these lenses mask corneal surface astigmatism and improve best-corrected VA 33. Thus these lenses are extremely useful in patients with advanced ectasia where the patients are intolerant to CL, or immediate surgery is not possible, or when surgery is refused by the patient.…”

“…Thus these lenses are extremely useful in patients with advanced ectasia where the patients are intolerant to CL, or immediate surgery is not possible, or when surgery is refused by the patient. These lenses have also been found to be useful in various ocular surface disorders such as Stevens-Johnson syndrome, Sjogren syndrome graft versus host disease, chemical injuries, dry eyes, limbal stem cell deficiency, ocular cicatricial pemphigoid, exposure keratitis and toxic epidermal necrolysis 33. The limitation of the  use of scleral lenses is high cost, reduced tear exchange and difficult insertion-removal, which requires considerable practice 28 32–34 Table 2.…”

Contact lens in keratoconus

“…There is renewed interest over the last few years because of the availability of high Dk material and newer designs. [13252627] These lenses are indicated when all other contact lenses fail to improve the vision or because of inability to get an optimal fit with RGP, RGP intolerance, 3 and 9 O’ clock staining of the cornea, vascularisation with PBCL, advanced keratoconus or scarring in the cornea[25262728] [Fig. 6].…”