Öèòàòà:
Ñîîáùåíèå îò ainakoz
3. Óâ. Îôòàëüìèñò! Ãäå â ETDRS óêàçàíû òî÷íûå ïàðàìåòðû ËÊ? Ïðîñâÿòèòå òóãîäóìà, à òî ìîæåò ÿ çðÿ íåñêîëüêî ëåò ïîòðàòèë íà òî ÷òîáû ïîíÿòü è íàó÷èòüñÿ ëå÷èòü ÄÐ?
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Áîëüøèíñòâî ðóêîâîäñòâ ïðè îïèñàíèè òåõíè÷åñêèõ ïàðàìåòðîâ ëàçåðíûõ êîàãóëÿöèé â ETDRS ññûëàþòñÿ íà ðåïîðò ¹3 ETDRS: The Early Treatment Diabetic Retinopathy Study Research Group. Techniques for scatter and local photocoagulation treatment of diabetic retinopathy: Early Treatment Diabetic Retinopathy Study Report no. 3. Int Ophthalmol Clin. 1987;27:254–264.
Ñðåäè íèõ îïðåäåëåíû ðàçìåð ëàçåðíîãî ïÿòíà, èíòåíñèâíîñòü íàíîñèìîãî îæîãà, ðàçìåð ýòîãî êîàãóëÿòà, ýêñïîçèöèÿ ëàçåðíîãî èçëó÷åíèÿ, íåîáõîäèìîå ÷èñëî êîàãóëÿòîâ, ÷èñëî ñåññèé äëÿ çàâåðøåíèÿ ïåðâè÷íîé êîàãóëÿöèè... Ò.å. âñ¸ ïðîäóìàíî çà íàñ. Ïðè ýòîì â ýòèõ æå ðåïîðòàõ ETDRS äåéñòâèòåëüíî åñòü äîïóùåíèÿ, ïîçâîëÿþùèå ìåíÿòü ýòè ïàðàìåòðû â îïðåäåë¸ííûõ ñëó÷àÿõ.
Öèòàòà:
The intensity of the laser burn was described in the ETDRS as ‘‘moderately intense white burns that do not spread to become appreciably larger than
500 mm.’’68
To achieve a desired intensity the treating
ophthalmologist may make adjustments in several
laser parameters. The laser spot size and duration
are first selected after which the power is adjusted to
reach the desired goal of retinal whitening.68 The
ETDRS protocol called for a setting of 500 mm for
the diameter of the laser spot using a Goldmann
lens. This setting was adjusted to 250–300 mm when
using the Rodenstock lens to achieve a similar effect
without changing the number of burns required for
a complete initial treatment. However, calculations
suggest that a photocoagulator spot size setting of
383 mm using a Rodenstock panfundoscopic lens
might more closely approximate the retinal photocoagulative
effect of a spot setting of 500 mm while
using a Goldmann lens (Table 9.6).156–158 In the
ETDRS, allowance was made for adjusting to a
smaller spot size to reach the desired intensity in
eyes with opaque media (cataract or vitreous
hemorrhage).68 The spot size may also be reduced
to allow for better pain control.128,132 When using
smaller spot sizes, a greater number of burns are
needed to treat a comparable area of the retina.
The laser flash duration in the ETDRS was 0.1 s,
but longer duration was allowed if needed to reach
the intensity goal as needed in eyes with opaque
media.68 Alternatively, the flash duration may be
shortened in an effort to decrease pain with
treatment.128 Laser flashes with shorter duration
(0.01–0.05 s) are less painful than longer duration
(0.1 s) controlling for end point laser intensity.131,132
Burns longer than 0.1 s duration may
increase the risk of traction retinal detachment following
treatment for PDR.160 Shorter pulse duration
is associated with increased risk of chorioretinal
hemorrhage.161,162
With some exceptions the ETDRS required
direct, confluent treatment (200–1000 mm, 0.1–0.5
s, moderately intense whitening) of small, flat areas
of NVE (not more than 2 disk areas, i.e., circle of 1.5
disk diameter) avoiding treatment closer than
500–1000 mm from the center of the macula. The
base of elevated NVE was treated confluently as
well. Although direct photocoagulation may be currently
less popular for the purpose of regression of
NV, there may be a role for treating NVE to create
an adhesion in order to reduce the risk of retinal
detachment from future vitreous/membrane contraction.
119,174
The ETDRS protocol specified the details regarding
the duration of a laser session, the number of
sessions, the time between sessions, and the definition
of completion of PRP. The number of laser burns per
session did not exceed 900 in order to avoid complications
from excessive treatment.68 However, when
urgent treatment completion is needed, exceeding this
guideline is not proscribed in clinical practice.178
Alternatively, fewer laser burns per session may be
considered in a sensitive patient or when shallow
anterior chamber angles threaten closure.67
The number of sessions to complete initial PRP
was two or more in the ETDRS.68
The ETDRS protocol defined the completion of
PRP in terms of total laser applications from all
initial treatment sessions. Between 1200 and 1600
laser burns were required for initial PRP to be complete.
68
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Diabetic Retinopathy: Evidance Based Management (David J. Browning) 2010
23.12.2011, 22:14
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