None listed
Conditions
Brief summary
It has been estimated that 1 in every 750 individuals worldwide likely to have keratoconus, a condition that affects the front transparent structure of the eye called cornea. Whereas normal healthy corneas are generally spherical in shape, eyes with keratoconus assume conic shape thereby affecting vision of the individual. The onset of this condition is generally during adolescence and the progresses until the age of 40. Early detection of this condition is important to apply appropriate clinical management strategies. Currently keratoconus is detected early by the use of a diagnostic instrument called corneal topographer that assesses shape of the front surface of the eye and provide certain corneal indices to differentiate keratoconus from normal eyes. Unfortunately, corneal topographers are expensive and are rarely available in rural optometric practices making it difficult to detect keratoconus in the rural areas. The primary purpose of this research study is develop a smart phone based photography technique that indirectly captures the shape of the cornea, the shape indices thus determined from the reconstructed corneal shape will help differentiate keratoconus from normals, eliminating the dependency on the expensive corneal topographers that are rarely available in rural optometric practices. Individuals aged between 18 and 40 years who are diagnosed to have keratoconus from various optometry and ophthalmology practices in Sydney are enrolled in this study. Individuals with healthy corneas falling in the same age range will also be enrolled into this study but will be classified as controls. Participants who are currently rigid contact lens wearers, have intolerance to rigid contact lens wear and have astigmatism more than 2 dioptre are not eligible to participate in this study. Standard optometric tests including vision test, determination of spectacle power, assessment of corneal shape (topography) and a anterior eye health assessment using a slit lamp will be performed. Rigid contact trial lenses will be applied to one or both eyes. A standard orange dye (Sodium fluorescein) will then be applied to aid the visibility of tears under the contact lens. Anaesthetic eye drops will be used to avoid any discomfort that may arise from the applied rigid contact lenses. Anterior eye photograph, while the contact lens is in place, will be captured using a smart phone. A custom software program will analyse the dyed tear layer behind the contact lens to reconstruct underlying corneal shape providing corneal shape indices. These corneal shape indices will be used to detect keratoconus from normal eyes.
Interventions
The researchers intend to photograph participant's more severely graded eye according to the KISA index, (or the right eye for controls) using a smart phone after applying trial rigid contact lenses. In order to minimise discomfort associated with the application of the contact lens, one drop of Alcaine 0.5% (Proxymetacaine hydrochloride) will be instilled prior to the application of the trial lens. Further, participant's tears are stained using a wetted sodium fluorescein (1 mg) strip to aid t
The researchers intend to photograph participant's more severely graded eye according to the KISA index, (or the right eye for controls) using a smart phone after applying trial rigid contact lenses. In order to minimise discomfort associated with the application of the contact lens, one drop of Alcaine 0.5% (Proxymetacaine hydrochloride) will be instilled prior to the application of the trial lens. Further, participant's tears are stained using a wetted sodium fluorescein (1 mg) strip to aid the visibility of tears under the contact lens during smart phone photography. The exposure duration to contact lens, topical anaesthesia and fluorescein dye lasts approximately 10 minutes. During which time an anterior eye photograph will be obtained using a smart phone. This photograph taken with the optometrists' smartphone will be input to image processing, and these preceding steps will be collectively known as SPARK. It follows from these steps that SPARK is a technique any optometrist may employ using their personal smartphone, rather than a device sold to the optometrist. A therapeutically endorsed, qualified optometrist will conduct the study at the UNSW School of Optometry and Vision Science by applying the SPARK technique.
Sponsors
University of New South Wales
Eligibility
Sex/Gender
All
Age
18 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
Individuals who are clinically diagnosed as keratoconus in one or both eyes based on standard optometric tests (Test group) Individuals with no clinical signs of keratoconus or other corneal ectatic conditions (control/comparator group)
Exclusion criteria
Severe dry eye Sensitivity towards rigid contact lenses Allergies anaesthetic eye drops Corneal ectasia other than keratoconus, Current rigid lens wearers (including orthokeratology)
Outcome results
None listed