Oftalʹmologiâ (Nov 2020)
The Need for the Retina’s Surface “Drying” during Macular Hole Surgery
Abstract
Purpose: to determine the relevance of retina’s surface “drying” during vitrectomy at the stage of exchange of infusion solution for air based on an experimental study and calculation of the geometric dimensions of a drop of moisture formed in the macular region.Patients and Methods. There were 10 patients (10 eyes), who had a vitrectomy for a macular tear with air injection in one eye. Their age was from 50 to 78 (64.0 ± 3.1), the size of the macular tear 250–631 (431.6 ± 44.3) mkm. After 27G subtotal vitrectomy intake of fluid formed after fluid-air exchange was performed and its volume was measured in equal time intervals 3 times. The next step is to determine the shape of a drop of intraocular fluid (IOF) that forms on the surface of the retina during BSS exchange. For example, in the cadaveric eye, the wetting of the retinal surface was studied with the volume of liquid that was obtained during the operation, and its edge wetting angle was measured. Given the fact that INFLOW during surgery formed from two sources: the result of the production of the ciliary body (CB) (2,5–4,0 μl/min) and dehydration of the vitreous body (VB) due to the pressure of the air supplied in the vitreal cavity was calculated drop diameter INFLOW first, when the product of TST and dehydration VB (CB + VB); second, only if the production CT. This made it possible to understand how a drop of HGH formed during the operation will be projected onto the surface of the macula. Results. Volume of intraocular fluid taken during surgery was 60–80 microliters (68.1 ± 2.8) for 3 minutes, or 22.7 microliters per minute. Rate of fluid formation decreased by 18–25 % for 9 minutes. Contact angle of wetting made 14.5°. Drop diameter calculated for ciliary body secretion and vitreous remnants dehydration equals 17.98 mm. Drop diameter calculated for ciliary body secretion alone equals 2.6 mm. Conclusions. “Drying” of the retina during macular hole surgery is impractical as intraocular fluid is constantly formed on the retina surface. Its volume is sufficient to cause opening of the hole. Refusal from this manipulation would not influence anatomic efficacy of the operation and would reduce surgical trauma.
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