Explain the effects of RGP on health
Answers
Answer:
Explanation:
Keratoconus, which was first described in detail in 1854, derives from the Greek words Kerato (cornea) and Konos (cone). [1] Keratoconus is the most common primary ectasia. The condition is noninflammatory, self-limiting ectasia of the axial portion of the cornea. It is characterized by thinning and steepening of the central or paracentral cornea that leads to a reduction in vision. [2] Corneal thinning normally occurs in the inferio-temporal and central part of the cornea. A superior portion also has found to be affected. [2] The incidence appears to be similar between females and males, with slightly higher incidence in males. [3] Keratoconus is always bilateral with 2% to 7% of the cases being unilateral. [2]
The cause of keratoconus is unknown. Some studies have found that keratoconus runs in families, [4] and it found to be happening more often in people with certain ocular and systemic conditions such as allergic conditions, chronic eye rubbing, but most often, there is no eye injury or disease that could explain why the eye starts to change. [5],[6],[7]
Keratoconus usually begins in the teenage years, [8] but it can also start in childhood or up to about age of 30 years. The changes in the shape of the cornea occur slowly and gradually, usually over several years. [9]
In the early stages, keratoconus can be treated with spectacles or regular soft contact lenses. [10] Custum soft toric contact lenses as keratosoft lenses and Novakone lenses are designed to treat mild to moderate keratoconus. [11] However, as the disease progresses the cornea becomes more irregular and spectacles or soft lenses no longer can treat it, so that rigid gas-permeable (RGP) contact lenses are the options used to correct moderate and advanced keratoconus. [12] Some patients with mild or advanced keratoconus cannot tolerate RGP contact lenses they can be corrected with piggy baking contact lenses in which RGP contact lenses are fitted over soft lenses. [11] Different hybrid contact lenses were designed specifically for keratoconus. These hybrid contact lenses combine rigid center with a soft peripheral skirt to increase comfort and tolerance. [13]
Contact lens wear can increase dry eye symptoms because all contact lens materials significantly and adversely affected tear physiology by increasing the evaporation rate and decreasing tear thinning time. [14] Keratoconus was reported to affect significantly tear functions, which seem to get worse with the extent of keratoconus. [15] Few studies have reported the effect of RGP contact lens wear on tear film of eyes with keratoconus. This study aimed to evaluate the effect of RGP contact lens wear on the tear film quality and quantity among keratoconic patients.
The study is a cross-sectional hospital based study. All keratoconus patients (wearing and not wearing RGP contact lenses) who attended Makka Eye Complex and Alfaisal Eye Hospital were included in this study. Subjects with ocular or systemic diseases or those who use any drugs that may interfere with the tear film were excluded.
Patients' demographic data (age, gender, and history of wearing contact lenses, general and ocular health) were taken. The inner eyes were examined using Heine ophthalmoscope. Shinn-Nippon corneal topographer was used for corneal mapping to determine the presence and severity of keratoconus. Based on the modified Amsler-Krumeich scale, keratoconus was classified to mild (>45.00 D), moderate (>45.00 D and <52.00 D), advanced (>52.00 D and <62 D), and severe (>62.00 D). Hagg Streit slit lamp was used to examine the outer eye, assess the fitting of contact lenses. To evaluate the tear volume a 35 mm × 5 mm Schirmer test strips was placed at the junction of medial 2/3 and lateral 1/3 of the lower lid in the fornix of the patients eye for 5 min, and after that the strip was removed and the length of moisture part was recorded in millimeters according to Khurana, [16] then the results were graded as normal (10-15 mm), dry eye (<10 mm) and watery (>15 mm). The test was done for both eyes. [17]
Tear film breakup time (TBUT) test was carried using Haag-Streit slit lamp in a bright light and cobalt blue filter. The subject's inferior bulbar conjunctiva of the eye was swiped with a saline wetted fluorescein strip (Fluorescein, Haag-Streit International, Switzerland). The patient was asked to blink several times after that he was asked to stop blinking and his eye was observed thought the slit lamp. The time between last blink and the appearance of the spots or streaks in the tear film was taken as the TBUT. Three readings were taken with stopwatch, recorded, and then the reading was calculated from the average of these readings. The results were then graded as normal (≥10 s) and abnormal
Please Mark As Brainist